以下是代码：

1. package thread2;
   
2. 
   
3. class Res {
   
4. private String name;
   
5. private String sex;
   
6. private boolean flag = false;
   
7. 
   
8. public synchronized void set(String name, String sex) {
   
9. if (flag)
   
10. try {
    
11. this.wait();
    
12. } catch (InterruptedException e) {
    
13. e.printStackTrace();
    
14. }
    
15. this.name = name;
    
16. this.sex = sex;
    
17. flag = true;
    
18. this.notify();
    
19. }
    
20. 
    
21. public synchronized void out() {
    
22. if(!flag)
    
23. try {
    
24. this.wait();
    
25. } catch (InterruptedException e) {
    
26. e.printStackTrace();
    
27. flag=false;
    
28. this.notify();
    
29. }
    
30. 
    
31. System.out.println((name + "........." + sex));
    
32. }
    
33. }

复制代码

1. package thread2;
   
2. 
   
3. public class Input implements Runnable {
   
4. private Res r;// 建立一个引用
   
5. Input(Res r) {
   
6. this.r = r;
   
7. }
   
8. 
   
9. public void run() {
   
10. int x = 0;
    
11. while (true) {
    
12. if (x == 0)
    
13. r.set("milk", "man");
    
14. else
    
15. r.set("丽丽", "女女女女女女女女女");
    
16. x = (x + 1) % 2;
    
17. 
    
18. }
    
19. 
    
20. }
    
21. }

复制代码

1. package thread2;
   
2. 
   
3. public class Output implements Runnable {
   
4. private Res r;
   
5. 
   
6. Output(Res r) {
   
7. this.r = r;
   
8. }
   
9. 
   
10. public void run() {
    
11. while(true){
    
12. r.out();
    
13. }
    
14. }
    
15. }

复制代码

1. package thread2;
   
2. 
   
3. 
   
4. public class InputOutputDemo
   
5. {
   
6. public static void main(String[] args)
   
7. {
   
8. Res r=new Res();
   
9. 
   
10. new Thread(new Input(r)).start();
    
11. new Thread(new Output(r)).start();
    
12. 
    
13. 
    
14. 
    
15. }
    
16. 
    
17. }

复制代码

以下是打印结果，打印的全部都是这样的，不应该是交替打印吗？如打印完milk....man后再打印丽丽......女女女女女女？：
milk.........man
milk.........man
milk.........man
milk.........man
milk.........man
milk.........man

package thread2;

class Res {
private String name;
private String sex;
private boolean flag = false;

public synchronized void set(String name, String sex) {
if (flag)
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
this.name = name;
this.sex = sex;
flag = true;
this.notify();
}

public synchronized void out() {
if(!flag)
try {
this.wait();
} catch (InterruptedException e)
{
     e.printStackTrace();
  //   flag=false;
   //  this.notify();//写代码不够仔细啊，咋能把这两句代码放在catch（）里面啊。
}
     flag=false;
     this.notify();
System.out.println((name + "........." + sex));
}
}

问题已解决，谢谢