Ctrl+d    //复制当前行到下一行
Ctrl+Alt+I    //自动对齐
Ctrl+左键    //查看文档
Shift+点第一个和点最后一个    //多选
Alt+Insert    //生成构造器
Ctrl+H    //继承关系
Ctrl+Alt+T    //将代码包在一个块中，例如try/catch
Ctrl+B    //看方法的源码
Alt+7    //打开一个窗口，可以看到类的所有信息
Alt    //多选

低 -------------------------------------> 高
byte,short,char-> int-> long-> float-> double

运算中，不同数据类型的数据先转化为同一类型，然后进行运算

//操作比较大的数的时候，注意溢出问题
//JDK7新特性，数字之间可以用下划线分割
int money = 10_0000_0000;
int years = 20;
int tota1 = money*years;//-1474836480,计算的时候溢出了
int total2 = money*(long)years;//20000000000

public class Hello {
    //类变量 static
    static double salary = 2500;

    //实例变量；从属于对象；
    String name;
    int age;

    public static void main(String[] args) {
        //局部变量；必须声明和初始化值
        int i = 10;
        System.out.println(i);

        //变量类型 变量名字 = new Hello();
        Hello h = new Hello();
        System.out.println(h.name);
        System.out.println(h.age);

        //类变量 static
        System.out.println(salary);
    }
}

static final double PI = 3.14;
//常量名一般用大写字母和下划线:MAX_VALUE
//类名一般首字母大写+驼峰

幂运算
double pow = Math.pow(2,3);

package pkg1[.pk2[.pkg3...]];

javadoc -encoding UTF-8 -charset UTF-8 Doc.java

Tools->Generate JavaDoc

//创建一个扫面器对象，用于接收键盘数据
     Scanner scanner = new Scanner(System.in);

     System.out.println("使用next方式接收：");

     //判断用户有没有输入字符串
     if(scanner.hasNext()){
         //使用next方式接收
         String str = scanner.next();
         System.out.println("输出的内容为："+str);
     }

     System.out.println("使用nextLine方式接收：");

     //判断用户有没有输入字符串
     if(scanner.hasNextLine()){
         //使用next方式接收
         String str = scanner.nextLine();
         System.out.println("输出的内容为："+str);
     }


     //凡是属于IO流的类如果不关闭会一直占用资源，用完就关
     scanner.close();

if(布尔表达式1){

}else if(布尔表达式2){

}else if(布尔表达式3){

}

switch(expression){

	case value:
		//语句
		break;
	case value:
		//语句
		break;
	default:
		//语句
}

while(布尔表达式){
	//循环内容
}

do{
	//代码语句
}while(布尔表达式)

for(初始化;布尔表达式;更新){
	//代码语句
}

int[] number = {10,20,30,40,50};

for(int x:number){
	System.out.println(x);
}

修饰符 返回值类型 方法名（参数类型 参数名）{

	...

	方法名

	...

	return 返回值；

}

public static void max(int num1,int num2){
	
}

dateType[] arrayRefVar;
dateType[] arrayRefvar = new dataType[arraySize];

//静态初始化
int[] a = {1,2,3};
Man[] mans = {new Man(),new Man()};

//动态初始化
int [] a = new int[2];
a[0]=1;
a[1]=2;

for(int array : arrays){
	System.out.println(array);
}

int[][] a = {{},{}};

int[][] array1 = new int[11][11];
array1[1][2] = 1;
array1[2][3] = 2;

int sum = 0;
for(int i = 0; i < 11; i++)
	for(int j = 0; j < 11; j++)
		if(array1[i][j] != 0)
			sum++;

int[][] array2 = new int[sum+1][3];

array2[0][0] = 11;
array2[0][1] = 11;
array2[0][2] = sum;

int count = 0;
for(int i = 0; i < array1.length; i++)
	for(int j = 0; j < array1.length; j++)
		if(array1[i][j] != 0){
			count++;
			array2[count][0] = i;
			array2[count][1] = j;
			array2[count][2] = array1[i][j];
		}

Student s = new Student();
System.out.println(s instanceof Student);    //true

public class text {
    public static void main(String[] args) {
        int a = 1;
        int b = 0;

		//捕获多个异常：从小到大
        try {//try监控区域
            System.out.println(a / b);
        }catch(Error e){//catch（想要捕获的异常类型！）捕获异常
            System.out.println("Error");
        }catch (Exception e) {
            System.out.println("Exception");
        }catch(Throwable e){
            System.out.println("Throwable");
        } finally{
            System.out.println("finally");
        }
    }
}

public class text {
    public static void main(String[] args) {
        try {
            new text().test(1,0);
        } catch (ArithmeticException e) {
            e.printStackTrace();
        }
    }
    public void test(int a,int b) throws ArithmeticException{
        if(b==0){
            throw new ArithmeticException();//主动抛出异常，一般在方法中使用
        }
    }
}

public class Test {
    static void test(int a)throws MyException{
        System.out.println("传递的参数为："+a);

        if(a>10){

                throw new MyException(a);
        }

        System.out.println("OK");
    }

    public static void main(String[] args)  {
        try {
            test(11);
        } catch (MyException e) {
            e.printStackTrace();
        }
    }
}

public class MyException extends Exception{

    //传递数字>10
    private int detail;

    public MyException(int x) {
        this.detail=x;
    }

    @Override
    public String toString() {
        return "MyException{" +
                "detail=" + detail +
                '}';
    }
}

public class Test {
    //jak5之前，手动装箱和手动拆箱
    int n1 = 100;
    Integer integer = new Integer(n1);
    Integer integer1 = Integer.valueOf(n1);
    
    int i = integer.intValue();
    
    //jdk5后，就可以自动装箱和自动拆箱
    int n2 = 200;
    //自动装箱 int->Integer
    Integer integer2 = n2;
    //自动拆箱 Integer->int
    int n3 = integer2;
}

//包装类（Integer）->String
Integer i = 100;
//方式1
String str1 = i + "";
//方式2
String str2 = i.toString();
//方式3
String str3 = String.valueOf(i);

//String -> 包装类(Integer)
String str4 = "123456";
Integer i2 = Integer.parseInt(str4);
Integer i3 = new Integer(str4);

String s1 = new String();    //初始化新创建的 String对象，使其表示空字符序列。

char[] chs = {'a','b','c'};
String s2 = new String(chs);    //根据字符数组的内容来创建字符串对象

byte[] bys = {97,98,99};
String s3 = new String(bys);    //根据字节数组的内容来创建字符串对象

String s4 = "abc";    //直接赋值的方式创建字符串对象

public class StringTest {
    public static void main(String[] args) {
        String name = "xingchuwu";
        String password = "123456";
        Scanner scanner = new Scanner(System.in);
        String name1;
        String password1;
        for(int i=0;i<3;i++){

            System.out.print("请输入用户名：");
            name1 = scanner.nextLine();
            System.out.print("请输入密码：");
            password1 = scanner.nextLine();
            if(name1.equals(name) && password1.equals(password)){
                System.out.println("登录成功！");
                break;
            }else if(i==2) {
                System.out.println("您的账号已被锁定！");
            }else {
                    System.out.println("登录失败！你还有" + (2-i) + "次机会");
            }
        }
    }
}

public class StringTest {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String line = sc.nextLine();
        for(int i=0;i<line.length();i++){
            System.out.println(line.charAt(i));
        }
    }
}

//创建一个空白可变字符串对象，不含任何内容
StringBuilder sb = new StringBuilder();
System.out.println("sb:"+sb);
System.out.println("sb.length():"+sb.length());

//根据字符串的内容，来创建可变字符串对象
StringBuilder sb2 = new StringBuilder("hello");
System.out.println("sb2:"+sb2);
System.out.println("sb2.length():"+sb2.length());

public class StringTest {
    public static void main(String[] args) {
        StringBuilder sb = new StringBuilder();

        //public StringBuilder append(任意类型); 添加数据，返回对象本身
//        sb.append("hello");
//        sb.append(" ");
//        sb.append("world");

        //链式编程
        sb.append("hello").append(" ").append("world");
        System.out.println(sb);
		
		//public StringBuilder reverse(); 返回相反的字符序列
        sb.reverse();
        System.out.println(sb);
    }
}

StringBuilder sb = new StringBuilder("hello")

String s = sb.toString;

StringBuilder sb1 = new StringBuilder(s);

//public Date();分配一个Date对象，并初始化，以便它代表它被分配的时间，精确的毫秒
   Date d1 = new Date();
       System.out.println(d1);    //Sun Dec 26 23:28:48 CST 2021

       //public Date(long date); 分配一个Date对象，并将其初始化为便是从标准基准时间起指定的毫秒数
       long date = 1000*60*60;
       Date d2 = new Date(date);
       System.out.println(d2);    //Thu Jan 01 09:00:00 CST 1970

Date d = new Date();
//public long getTime();获取的是日期对象从1970年1月1日 00：00：00到现在的毫秒值。
System.out.println(d.getTime());

//public void setTime(long time);设置时间，给的时毫秒值。
long time = System.currentTimeMillis();//当前时间
d.setTime(time);
System.out.println(d);

//格式化，从Date到String
//public final String format(Date date);将日期格式化成日期/时间字符串
Date d = new Date();
SimpleDateFormat sdf = new SimpleDateFormat();
String s = sdf.format(d);
System.out.println(s);//21-12-27 上午12:53

SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");
String s1 = sdf1.format(d);
System.out.println(s1);//2021年12月27日 00:53:06

//解析：从String到Date
//public Date parse(String source);从给定的字符串开始解析文本以生成日期
String s2 = "2016-12-13 05:02:01";
SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date d2 = sdf2.parse(s2);
System.out.println(d2);//Tue Dec 13 05:02:01 CST 2016

//Calendar提供了一个类方法getInstance用于获取Calendar对象，其日历字段已实验当前日期和时间初始化
Calendar c = Calendar.getInstance();
//public int get(int field);返回给定日历字段的值
int year = c.get(Calendar.YEAR);
int month = c.get(Calendar.MONTH) + 1;
int date = c.get(Calendar.DATE);
System.out.println(year + "年" + month + "月" + date + "日");

//public abstract void add(int field,int amount);根据日历的规则，将指定的时间量添加或减去给定的日历字段
//10年前的5天后
c.add(Calendar.YEAR,-10);
c.add(Calendar.DATE,5);
int year = c.get(Calendar.YEAR);
int month = c.get(Calendar.MONTH) + 1;
int date = c.get(Calendar.DATE);
System.out.println(year + "年" + month + "月" + date + "日");

//public final void set(int year,int month,int date);设置当前日历的年月日
Calendar c1 = Calendar.getInstance();
c1.set(2016,11,13);
int year1 = c1.get(Calendar.YEAR);
int month1 = c1.get(Calendar.MONTH)+1;
int date1 = c1.get(Calendar.DATE);
System.out.println(year1 + "年" + month1 + "月" + date1 + "日");

      Scanner sc = new Scanner(System.in);
      System.out.println("请输入年份：");
      int year = sc.nextInt();

      Calendar c = Calendar.getInstance();
      c.set(year,2,1);
      c.add(Calendar.DATE,-1);
      int date = c.get(Calendar.DATE);
      System.out.println(year + "年的2月份有" + date + "天");
      
      
      //请输入年份：
//2016
//2016年的2月份有29天

public class ArrayListDemo01 {
    public static void main(String[] args) {
        //public ArrayList();创建一个空的集合对象
        ArrayList<String> array= new ArrayList<String>();

        //public boolean add(E e);将指定的元素追加到此集合的末尾
        array.add("hello");
        array.add("world");
        array.add("java");

        //public void add(int index,E element)；在此集合中的指定位置插入指定的元素

        array.add(1,"javase");
        System.out.println("arrat:" + array);
    }
}

public class ArrayListDemo02 {
    public static void main(String[] args) {
        //创建一个空的集合对象
        ArrayList<String> array= new ArrayList<String>();

        //添加元素
        array.add("hello");
        array.add("world");
        array.add("java");

        //public boolean remove(Object o);删除指定的元素，返回删除是否成功
//        System.out.println(array.remove("world"));
//        System.out.println(array.remove("world"));

        //public E remove(int index);删除指定索引处的元素，返回被删除的元素
        System.out.println(array.remove(1));

        //public E set(int index,E element);修改指定索引处的元素，返回被修该的元素
        System.out.println(array.set(1,"javaee"));

        //public E get(int index);返回指定索引处的元素
        System.out.println(array.get(0));
        System.out.println(array.get(1));
       // System.out.println(array.get(2));

        //public int size();返回集合中的元素的个数
        System.out.println(array.size());
        
        //输出集合
        System.out.println("arrat:" + array);
    }
}

//创建Collection集合的对象，通过多态的方式，ArrayList()
Collection<String> c = new ArrayList<String>();

//添加元素：boolean add (E e)
c.add("hello");
c.add("hello1");
c.add("hello2");

System.out.println(c);

Collection<String> c = new ArrayList<String>();

      c.add("hello1");
      c.add("hello2");
      c.add("hello3");

      Iterator<String> it = c.iterator();

      while(it.hasNext()){
          System.out.println(it.next());
      }

List<String> list = new ArrayList<>();

        list.add("hello");
        list.add("hello");
        list.add("hello");
        list.add("hello");

        Iterator<String> iterator = list.iterator();
        while(iterator.hasNext()){
            System.out.println(iterator.next());
        }

for(元素数据类型 变量名 : 数组或者Collection集合){
	//在此处使用变量即可，该变量就是元素
}

int[] arr = {1,2,3,4};
for(int i : arr){
	System.out.println(i);
}

List<String> list = new ArrayList<String>();
list.add("hello");
list.add("hello2");
list.add("hello3");

for(String s : list){
	System.out.println(s);
}

Set<String> set = new HashSet<String>();
set.add("hello1");
set.add("hello2");
set.add("hello3");
for(String s : set){
	System.out.println(s);
}

public int compareTo(Student s){
	int num = this.age - s.age;
	int num2 = num == 0?this.name.compareTo(s.name):num;
	return num;
}

TreeSet<Student> ts = new TreeSet<Student>(new Comparator<Student>(){
	public int compare(Student s1,Student s2){
		int num = s1.getAge() - s2.getAge();
    	int num2 = num == 0?s1.getName().compareTo(s2.getName()):num;
    	return num2;
	}
})

public class Generic<T> {
    private T t;

    public T getT() {
        return t;
    }

    public void setT(T t) {
        this.t = t;
    }
}

public class GenericDemo {
    public static void main(String[] args) {
        Generic<String> g1 = new Generic<>();
        g1.setT("xingchuwu");
        System.out.println(g1.getT());

        Generic<Integer> g2 = new Generic<>();
        g2.setT(100);
        System.out.println(g2.getT());
    }
}

public class Generic{
   public <T> void show(T t){
   	   System.out.println(t);	
   }
}

public class GenericDemo {
    public static void main(String[] args) {
        Generic g = new Generic();
        g.show("xingchuwu");
        g.show(100);
    }
}

public interface Generic1<T> {
    void show(T t);
}

public class GenericImpl<T> implements Generic1<T> {
    @Override
    public void show(T t) {
        System.out.println(t);
    }
}

public class GenericDemo1 {
    public static void main(String[] args) {
        GenericImpl<String> g = new GenericImpl<>();
        g.show("xingchuwu");

        GenericImpl<Integer> g1 = new GenericImpl<>();
        g1.show(100);
    }
}

List<?> list1 = new ArrayList<Object>();
      List<?> list2 = new ArrayList<Number>();
      List<?> list3 = new ArrayList<Integer>();
      
      List<? extends Number> list4 = new ArrayList<Number>();
      List<? extends Number> list5 = new ArrayList<Integer>();

      List<? super  Number> list6 = new ArrayList<Object>();
      List<? super  Number> list7 = new ArrayList<Number>();

public class ArgsDemo {
    public static void main(String[] args) {
        System.out.println(sum(10,20));
        System.out.println(sum(10,20,30));
        System.out.println(sum(10,20,30,40));
    }

    public static int sum (int...a){
        int sum = 0;
        for(int i : a){
            sum += i;
        }
        return sum;
    }
}

public class MapDemo1 {
    public static void main(String[] args) {
        Map<String,String> map = new HashMap<>();

        map.put("xingchuwu","qianxiyun");
        map.put("52","1213");
        map.put("52","121399");

        System.out.println(map);
    }
}

public class MapDemo2 {
    public static void main(String[] args) {
        Map<String,String> map = new HashMap<>();

        map.put("xingchuwu","qianxiyun");
        map.put("52","1213");


//        System.out.println(map.remove("52"));

//        map.clear();

        System.out.println(map.containsKey("xingchuwu"));
        System.out.println(map.containsValue("qianxiyun"));
        System.out.println(map.size());
        System.out.println(map.isEmpty());


    }
}

public class MapDemo2 {
    public static void main(String[] args) {
        Map<String,String> map = new HashMap<>();

        map.put("xingchuwu","qianxiyun");
        map.put("52","1213");

        Set<Map.Entry<String,String>> entrySet = map.entrySet();
        for(Map.Entry<String,String> me : entrySet){
            String key = me.getKey();
            String value = me.getValue();
            System.out.println(key + ',' + value);
        }

    }
}

public class MapDemo3 {
    public static void main(String[] args) {
        ArrayList<HashMap> arrayList = new ArrayList<>();
        HashMap<String,String> hm1 = new HashMap<>();

        hm1.put("hello1","world1");
        hm1.put("hello2","world2");
        hm1.put("hello3","world3");

        HashMap<String,String> hm2 = new HashMap<>();
        hm2.put("hello4","world4");
        hm2.put("hello5","world5");
        hm2.put("hello6","world6");

        arrayList.add(hm1);
        arrayList.add(hm2);

        for(HashMap<String,String> hm : arrayList){
            Set<String> keySet = hm.keySet();
            for(String key : keySet){
                String value = hm.get(key);
                System.out.println(key + ',' + value);
            }
        }
    }
}

public class MapDemo4 {
    public static void main(String[] args) {
        HashMap<String, ArrayList<String>> hm =new HashMap<>();

        ArrayList<String> arrayList1 = new ArrayList<>();

        arrayList1.add("hello1");
        arrayList1.add("hello2");
        arrayList1.add("hello3");

        ArrayList<String> arrayList2 = new ArrayList<>();

        arrayList2.add("hello4");
        arrayList2.add("hello5");
        arrayList2.add("hello6");

        hm.put("hh",arrayList1);
        hm.put("hhh",arrayList2);

        Set<String> keySet = hm.keySet();
        for(String key : keySet){
            ArrayList<String> value = hm.get(key);
            for(String s : value)
                System.out.println(key + ' ' + s);
        }
    }
}

public class MapDemo5 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String str = sc.nextLine();

        HashMap<Character,Integer> hm = new HashMap<>();


        for(int i=0;i<str.length();i++){
            char key = str.charAt(i);

            if(!hm.containsKey(key)){
                hm.put(key,1);
            }else{
                int num = hm.get(key);
                hm.put(key,num+1);
            }
        }

//        Set<Character> set = hm.keySet();
//        for(Character c : set){
//            Integer value = hm.get(c);
//            System.out.print(c);
//            System.out.print("(");
//            System.out.print(value);
//            System.out.print(")");
//        }

        StringBuilder sb = new StringBuilder();

        Set<Character> keySet = hm.keySet();
        for(Character key : keySet){
            Integer value = hm.get(key);
            sb.append(key).append("(").append(value).append(")");
        }
        System.out.println(sb);
    }
}

public class CollectionsDemo11 {
    public static void main(String[] args) {
        List<Integer> list = new ArrayList<>();

        list.add(30);
        list.add(50);
        list.add(20);
        list.add(40);
        list.add(10);

        System.out.println(list);

        Collections.sort(list);
        System.out.println(list);

        Collections.reverse(list);
        System.out.println(list);

        Collections.shuffle(list);
        System.out.println(list);
    }
}

public class CollectionsDemo2 {
    public static void main(String[] args) {
        ArrayList<Student> arrayList = new ArrayList<>();

        Student s1 = new Student("xingchuwu",20);
        Student s2 = new Student("qianxiyunu",19);
        Student s3 = new Student("xxx",35);
        Student s4 = new Student("aaa",20);

        arrayList.add(s1);
        arrayList.add(s2);
        arrayList.add(s3);
        arrayList.add(s4);

        Collections.sort(arrayList, new Comparator<Student>() {
            @Override
            public int compare(Student s1, Student s2) {
                int num = s1.getAge() -s2.getAge();
                int num2 = num == 0 ? s1.getName().compareTo(s2.getName()) : num;
                return num2;
            }
        });

        for(Student s : arrayList){
            System.out.println(s.getName() + ' ' + s.getAge());
        }
    }
}

public class CollectionsDemo3 {
    public static void main(String[] args) {
        ArrayList<String> arrayList = new ArrayList<>();

        String[] colors = {"♦","♠","♥","♣"};
        String[] numbers = {"2","3","4","5","6","7","8","9","10","J","Q","K","A"};
        for(String color : colors){
            for(String number : numbers)
                arrayList.add(color+number);
        }
        arrayList.add("大王");
        arrayList.add("小王");

        Collections.shuffle(arrayList);

        ArrayList<String> dzArray = new ArrayList<>();
        ArrayList<String> nmArray1 = new ArrayList<>();
        ArrayList<String> nmArray2 = new ArrayList<>();
        ArrayList<String> dpArray = new ArrayList<>();

        for(int i=0; i<arrayList.size();i++){
            String poker = arrayList.get(i);

            if(i >= arrayList.size()-3){
                dpArray.add(poker);
            }else if(i%3==0){
                dzArray.add(poker);
            }else if(i%3==1){
                nmArray1.add(poker);
            }else if(i%3==2){
                nmArray2.add(poker);
            }
        }

        lookPoker("地主",dzArray);
        lookPoker("农民1",nmArray1);
        lookPoker("农民2",nmArray2);
        lookPoker("地牌",dpArray);
    }

    //看牌方法
    public static void lookPoker(String name,ArrayList<String> arrayList){
        System.out.println(name + "的牌是");
        for(String poker : arrayList){
            System.out.print(poker + " ");
        }
        System.out.println();
    }
}

public class CollectionsDemo4 {
    public static void main(String[] args) {

        HashMap<Integer,String> hm = new HashMap<>();

        String[] colors = {"♦","♠","♥","♣"};
        String[] numbers = {"2","3","4","5","6","7","8","9","10","J","Q","K","A"};
        hm.put(0,"大王");
        hm.put(1,"小王");
        int num = 2;
        for(String number : numbers){
            for(String color : colors){
                hm.put(num,color+number);
                num++;
            }
        }

        Set<Integer> keySet = hm.keySet();
        for(Integer key : keySet){
            String value = hm.get(key);
            StringBuilder sb = new StringBuilder();
            sb.append(key).append(":").append(value);
            System.out.println(sb);

        }
        ArrayList<Integer> arrayList = new ArrayList<>();
        for(int i=0;i<52;i++)
            arrayList.add(i);
        Collections.shuffle(arrayList);

        TreeSet<Integer> dzArray = new TreeSet<>();
        TreeSet<Integer> nmArray1 = new TreeSet<>();
        TreeSet<Integer> nmArray2 = new TreeSet<>();
        TreeSet<Integer> dpArray = new TreeSet<>();

        for(int i=0; i<arrayList.size();i++){
            Integer poker = arrayList.get(i);

            if(i >= arrayList.size()-3){
                dpArray.add(poker);
            }else if(i%3==0){
                dzArray.add(poker);
            }else if(i%3==1){
                nmArray1.add(poker);
            }else if(i%3==2){
                nmArray2.add(poker);
            }
        }

        lookPoker("地主",dzArray,hm);
        lookPoker("农民1",nmArray1,hm);
        lookPoker("农民2",nmArray2,hm);
        lookPoker("地牌",dpArray,hm);
    }

    public static void lookPoker(String name,TreeSet<Integer> arrayList,HashMap<Integer,String> hm){
        System.out.println(name + "的牌是");
        for(Integer poker : arrayList){
            System.out.print(hm.get(poker) + " ");
        }
        System.out.println();
    }
}

long start = System.currentTimeMillis();
for(int i = 0; i < 10000; i++){
	System.out.println(i);
}
long end = System.currentTimeMillis();
	System.out.println("共耗时：" + (end - start) + "毫秒");

public class FileDemo1 {
    public static void main(String[] args) {
        File f1 = new File("E:\\javadProgram\\javaIOTest\\java.txt");
        System.out.println(f1);

        File f2 = new File("E:\\javadProgram\\javaIOTest","java.txt");
        System.out.println(f2);

        File f3 = new File("E:\\javadProgram\\javaIOTest");
        File f4 = new File(f3,"java.txt");
        System.out.println(f4);
    }
}

public class FileDemo2 {
    public static void main(String[] args) throws IOException {
        File f1 = new File("E:\\javadProgram\\javaIOTest\\java.txt");
        System.out.println(f1.createNewFile());

        File f2 = new File("E:\\javadProgram\\javaIOTest\\javaSE");
        System.out.println(f2.mkdir());

        File f3 = new File("E:\\javadProgram\\javaIOTest\\javaWeb\\html");
        System.out.println(f3.mkdirs());
    }
}

public class FileDemo3 {
    public static void main(String[] args) {
        File f1 = new File("javaStudy.iml");

        System.out.println(f1.isDirectory());
        System.out.println(f1.isFile());
        System.out.println(f1.exists());

        System.out.println(f1.getAbsoluteFile());
        System.out.println(f1.getPath());
        System.out.println(f1.getName());

        File f2 = new File("E:\\javadProgram\\javaIOTest");
        String[] strArrays = f2.list();
        for(String str : strArrays)
            System.out.println(str);

        File[] fileArrays = f2.listFiles();
        for(File file : fileArrays){
            if(file.isFile())
                System.out.println(file.getName());
        }
    }
}

public class FileDemo4 {
    public static void main(String[] args) {
        File f = new File("E:\\javadProgram\\javaIOTest");
        if(f.exists())
            getAllFilePath(f);
    }
    public static void getAllFilePath(File f){
        File[] fileArray = f.listFiles();
        if(fileArray != null){
            for(File file : fileArray){
                if(file.isDirectory()){
//                    System.out.print(file.getPath());
//                    System.out.println(":");
                    getAllFilePath(file);
                }else if(file.isFile()){
                    System.out.println(file.getAbsoluteFile());
                }
            }
        }
    }
}

public class FileOutputStreamDemo1 {
    public static void main(String[] args) throws IOException {
        FileOutputStream fos = new FileOutputStream("E:\\javadProgram\\javaStudy\\src\\com\\chang\\base\\myIO\\ByteStreamDemo\\fos.txt");

        fos.write(97);
        
        fos.close();
    }
}

public class FileOutputStreamDemo2 {
    public static void main(String[] args) throws IOException {
        FileOutputStream fos = new FileOutputStream("E:\\javadProgram\\javaStudy\\src\\com\\chang\\base\\myIO\\ByteStreamDemo\\fos.txt");

        fos.write(97);
        byte[] bys = "abcde".getBytes();
        fos.write(bys);

        fos.write(bys,1,2);

        fos.close();
    }
}

public class FileOutputStreamDemo3 {
    public static void main(String[] args) {
        FileOutputStream fos = null;

        try {
            fos = new FileOutputStream("fos.txt");
            fos.write("hello".getBytes());
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if(fos != null){
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

public class FileInputStreamDemo1 {
    public static void main(String[] args) throws IOException {
        FileInputStream fis = new FileInputStream("fos.txt");

        int by;
        while((by = fis.read()) != -1){
            System.out.print((char)by);
        }

        fis.close();
    }
}

public class FileInputStreamDemo3 {
    public static void main(String[] args) throws IOException {
        FileInputStream fis = new FileInputStream("fos.txt");

        byte[] bys = new byte[1024];    //1024及其倍数
        int len;
        while((len = fis.read(bys)) != -1){
            System.out.println(new String(bys,0,len));
        }
        fis.close();
    }
}

public class FileInputStreamDemo2 {
    public static void main(String[] args) throws IOException {
        FileInputStream fis = new FileInputStream("fos.txt");
        FileOutputStream fos = new 					       FileOutputStream("E:\\javadProgram\\javaIOTest\\java.txt"); 

        int by;
        while((by = fis.read()) != -1){
            fos.write(by);
        }

        fis.close();
        fos.close();

    }
}

public class FileInputStreamDemo4 {
    public static void main(String[] args) throws IOException {
        FileInputStream fis = new FileInputStream("E:\\UpupooWallpaper\\1800011075\\previewFix.jpg");
        FileOutputStream fos = new FileOutputStream("E:\\javadProgram\\javaIOTest\\test.jpg");

        int by;
        while((by = fis.read()) != -1){
            fos.write(by);
        }

        fis.close();
        fos.close();
    }
}

public class CopyAviDemo {
    public static void main(String[] args) throws IOException {
        long startTime = System.currentTimeMillis();


//        method1();
//        method2();
//        method3();
        method4();

        long endTime = System.currentTimeMillis();
        System.out.println(endTime-startTime);
    }
    //基本字节流一次读写一个字节   107610ms
    public static void method1() throws IOException{
        FileOutputStream fos = new FileOutputStream("E:\\javadProgram\\javaIOTest\\1111.avi");
        FileInputStream fis = new FileInputStream("C:\\Users\\10923\\Videos\\Captures\\1111.avi");

        int by;
        while((by = fis.read()) != -1){
            fos.write(by);
        }

        fos.close();
        fis.close();
    }

    //基本字节流一次读写一个字节数组    143ms
    public static void method2() throws IOException{
        FileOutputStream fos = new FileOutputStream("E:\\javadProgram\\javaIOTest\\1111.avi");
        FileInputStream fis = new FileInputStream("C:\\Users\\10923\\Videos\\Captures\\11112.avi");

        byte[] bys = new byte[1024];
        int len;
        while((len = fis.read(bys)) != -1){
            fos.write(bys,0,len);
        }

        fos.close();
        fis.close();
    }

    //字节缓冲流一次读写一个字节    189ms
    public static void method3() throws IOException{

        BufferedInputStream bis = new BufferedInputStream(new FileInputStream("C:\\Users\\10923\\Videos\\Captures\\1111.avi"));
        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("E:\\javadProgram\\javaIOTest\\11113.avi"));

        int by;
        while((by = bis.read()) != -1){
            bos.write(by);
        }

        bos.close();
        bis.close();
    }

    //字节缓冲流一次读写一个字节数组    35ms
    public static void method4() throws IOException{
        BufferedInputStream bis = new BufferedInputStream(new FileInputStream("C:\\Users\\10923\\Videos\\Captures\\1111.avi"));
        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("E:\\javadProgram\\javaIOTest\\11114.avi"));

        byte[] bys = new byte[1024];
        int len;
        while((len = bis.read(bys)) != -1){
            bos.write(bys,0,len);
        }

        bos.close();
        bis.close();
    }

}

public class BufferStreamDemo {
    public static void main(String[] args) throws IOException {
        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("fos.txt"));

        bos.write("hello\r\n".getBytes());
        bos.write("world\r\n".getBytes());

        bos.close();

        BufferedInputStream bis = new BufferedInputStream(new FileInputStream("fos.txt"));

        byte[] bys = new byte[1024];
        int len;
        while((len = bis.read(bys)) != -1){
            System.out.println(new String(bys,0,len));
        }
    }
}

public class ConversionStreamDemo1 {
    public static void main(String[] args) throws IOException {
        OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("fos.txt"),"GBK");

        osw.write("行初雾");
        osw.close();

        InputStreamReader isr = new InputStreamReader(new FileInputStream("fos.txt"),"GBK");
        int ch;
        while((ch = isr.read()) != -1){
            System.out.println((char)ch);
        }
    }
}

public class OutputStreamWriterDemo {
    public static void main(String[] args) throws IOException {
        OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("fos.txt"));

        osw.write(97);
        osw.flush();

        char[] chs = {'a','b','c','d','e'};
        osw.write(chs);
        osw.flush();

        osw.write(chs,1,3);
        osw.flush();

        osw.write("hello");
        osw.flush();

        osw.write("hello",1,3);
        
        osw.close();
    }
}

public class InputStreamReaderDemo {
    public static void main(String[] args) throws IOException {
        InputStreamReader isr = new InputStreamReader(new FileInputStream("fos.txt"));

//        int ch;
//        while((ch = isr.read()) != -1){
//            System.out.println((char)ch);
//        }

        char[] chs = new char[1024];
        int len;
        while((len = isr.read(chs)) != -1){
            System.out.println(new String(chs,0,len));
        }

        isr.close();
    }
}

public class CopyJavaDemo01 {
    public static void main(String[] args) throws IOException {
        InputStreamReader isr = new InputStreamReader(new FileInputStream("E:\\javadProgram\\javaStudy\\src\\com\\chang\\base\\myIO\\ConversionStreamDemo\\ConversionStreamDemo1.java"));
        OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream("E:\\javadProgram\\javaIOTest\\copy.java"));

//        int ch;
//        while((ch = isr.read()) != -1){
//            osw.write(ch);
//        }

        char[] chs = new char[1024];
        int len;
        while((len = isr.read(chs)) != -1){
            osw.write(chs,0,len);
        }
        isr.close();
        osw.close();
    }
}

public class CopyJavaDemo02 {
    public static void main(String[] args) throws IOException {
        FileReader fr = new FileReader("E:\\\\javadProgram\\\\javaStudy\\\\src\\\\com\\\\chang\\\\base\\\\myIO\\\\ConversionStreamDemo\\\\ConversionStreamDemo1.java");
        FileWriter fw = new FileWriter("E:\\\\javadProgram\\\\javaIOTest\\\\copy.java");

//        int ch;
//        while((ch = fr.read()) != -1){
//            fw.write(ch);
//        }

        char[] chs =new char[1024];
        int len;
        while((len = fr.read(chs)) != -1){
            fw.write(chs,0,len);
        }

        fr.close();
        fw.close();

    }
}

public class CopyJavaDemo3 {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new FileReader("E:\\javadProgram\\javaStudy\\src\\com\\chang\\base\\myIO\\ConversionStreamDemo\\ConversionStreamDemo1.java"));
        BufferedWriter bw = new BufferedWriter(new FileWriter("E:\\javadProgram\\javaIOTest\\copy3.java"));

//        int ch;
//        while((ch = br.read()) != -1){
//            bw.write(ch);
//        }

        char[] chs = new char[1024];
        int len ;
        while((len = br.read(chs)) != -1){
            bw.write(chs,0,len);
        }

        br.close();
        bw.close();
    }
}

public class BufferedStreamDemo {
    public static void main(String[] args) throws IOException {
        BufferedWriter bw = new BufferedWriter(new FileWriter("fos.txt"));

        bw.write("hello\r\n");
        bw.write("hello\r\n");
        bw.close();

        BufferedReader br = new BufferedReader(new FileReader("fos.txt"));

        int ch;
        while((ch = br.read()) != -1){
            System.out.print((char)ch);
        }
        br.close();
    }
}

public class BufferedStreamDemo2 {
    public static void main(String[] args) throws IOException {
        BufferedWriter bw = new BufferedWriter(new FileWriter("fos.txt"));
        for(int i=0;i<10;i++){
            bw.write("hello"+i);
            bw.newLine();
            bw.flush();
        }

        bw.close();

        BufferedReader br = new BufferedReader(new FileReader("fos.txt"));
        String line;
        while ((line = br.readLine()) != null){
            System.out.println(line);
        }
        br.close();
    }
}

public class ArrayListToTxtDemo {
    public static void main(String[] args) throws IOException {
        ArrayList<String> arrayList = new ArrayList<>();
        arrayList.add("hello1");
        arrayList.add("hello2");
        arrayList.add("hello3");

        BufferedWriter bw = new BufferedWriter(new FileWriter("fos.txt"));

        for(String array : arrayList){
            bw.write(array);
            bw.newLine();
            bw.flush();
        }
        bw.close();
    }
}

public class TxtToArrayListDemo {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new FileReader("fos.txt"));

        ArrayList<String> arrayList = new ArrayList<>();
        String line;
        while((line = br.readLine()) != null){
            arrayList.add(line);
        }
        br.close();

        for(String s : arrayList){
            System.out.println(s);
        }
    }
}

public class CopyFolderDemo {
    public static void main(String[] args) throws IOException {
        File srcFolder = new File("E:\\javadProgram\\javaIOTest\\javaSE");

        String srcFolderName = srcFolder.getName();

        File destFolder = new File("E:\\javadProgram\\javaIOTest\\javaWeb",srcFolderName);

        if(!destFolder.exists()){
            destFolder.mkdir();
        }

        File[] files = srcFolder.listFiles();
        for(File srcFile : files){
            String srcFileName = srcFile.getName();
            File destFile = new File(destFolder,srcFileName);
            copyFile(srcFile,destFile);
        }
    }
    private static void copyFile(File srcFile,File destFile) throws IOException{
        BufferedInputStream bis = new BufferedInputStream(new FileInputStream(srcFile));
        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(destFile));

        byte[] bys = new byte[1024];
        int len;
        while((len = bis.read(bys)) != -1){
            bos.write(bys,0,len);
        }
        bis.close();
        bos.close();
    }
}

public class CopyFoldersDemo {
    public static void main(String[] args) throws IOException {
        File srcFile = new File("E:\\javadProgram\\javaIOTest");

        File destFile = new File("E:\\javadProgram\\javaIOTest2");

        copyFolder(srcFile,destFile);

    }

    private static void copyFolder(File srcFile,File destFile) throws IOException {
        if(srcFile.isDirectory()){
            String srcFileName = srcFile.getName();
            File destFolder = new File(destFile,srcFileName);
            if(!destFolder.exists()){
                destFolder.mkdir();
            }
            File[] files = srcFile.listFiles();
            for(File file : files){
                copyFolder(file,destFolder);
            }
        }else if(srcFile.isFile()){
            File newFile = new File(destFile,srcFile.getName());
            copyFile(srcFile,newFile);
        }
    }

    private static void copyFile(File srcFile, File destFile) throws IOException {
        BufferedInputStream bis = new BufferedInputStream(new FileInputStream(srcFile));
        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(destFile));

        byte[] bys = new byte[1024];
        int len;
        while((len = bis.read(bys)) != -1){
            bos.write(bys,0,len);
        }
        bis.close();
        bos.close();
    }
}

//总结：注意，线程开启不一定立即执行，由CPU调度执行
public class ThreadDemo1 extends Thread {
    @Override
    public void run() {
        for (int i = 0; i < 200; i++) {
            System.out.println("run------------" + i);
        }
    }

    public static void main(String[] args) {
        ThreadDemo1 threadDemo1 = new ThreadDemo1();
        threadDemo1.start();
        for (int i = 0; i < 1000; i++) {
            System.out.println("main-" + i);
        }
    }
}

public class ThreadDemo2 extends Thread{
    private String url;    //网络图片地址
    private String name;    //保存的文件名

    public ThreadDemo2(String url,String name){
        this.name = name;
        this.url = url;
    }

    @Override
    public void run() {
        WebDownloader webDownloader = new WebDownloader();
        webDownloader.downloader(url,name);
        System.out.println("下载了文件：" + name);
    }

    public static void main(String[] args) {
        ThreadDemo2 t1 = new ThreadDemo2("https://bkimg.cdn.bcebos.com/pic/730e0cf3d7ca7bcb3700f79abe096b63f624a80f?x-bce-process=image/resize,m_lfit,w_220,limit_1/format,f_auto","E:\\javadProgram\\javaIOTest\\1.jpg");
        ThreadDemo2 t2 = new ThreadDemo2("https://bkimg.cdn.bcebos.com/pic/730e0cf3d7ca7bcb3700f79abe096b63f624a80f?x-bce-process=image/resize,m_lfit,w_220,limit_1/format,f_auto","2.jpg");
        ThreadDemo2 t3 = new ThreadDemo2("https://bkimg.cdn.bcebos.com/pic/730e0cf3d7ca7bcb3700f79abe096b63f624a80f?x-bce-process=image/resize,m_lfit,w_220,limit_1/format,f_auto","3.jpg");

        t1.start();
        t2.start();
        t3.start();
    }
}

//下载器
class WebDownloader{
    //下载方法
    public void downloader(String url,String name){
        try {
            FileUtils.copyURLToFile(new URL(url),new File(name));
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("IO异常，downloader方法出现问题");
        }
    }
}