【java】多线程同步生产者消费者问题

 package 多线程;
 class Producer implements Runnable{
     private Data data;
     public Producer(Data data){
         this.data=data;
     }
     @Override
     public synchronized void run() {
         for(int i=0;i<50;i++){
             if(i%2==0){
                 this.data.setTitle("饼干");
                 try {
                     Thread.sleep(100);
                 } catch (InterruptedException e) {
                     e.printStackTrace();
                 }
                 this.data.setValue("麦香饼干");
             }else{
                 this.data.setTitle("饮料");
                 try {
                     Thread.sleep(100);
                 } catch (InterruptedException e) {
                     e.printStackTrace();
                 }
                 this.data.setValue("果汁好喝");
             }
         }
     }
 }
 class Consumer implements Runnable{
     private Data data;
     public Consumer(Data data){
         this.data=data;
     }
     @Override
     public synchronized void run() {
         for(int i=0;i<50;i++){
             try {
                 Thread.sleep(100);
             } catch (InterruptedException e) {
                 e.printStackTrace();
             }
             System.out.println("消费："+this.data.getTitle()+"->"+this.data.getValue());
         }
     }
 }
 class Data{
     private String title;
     private String value;
     public void setTitle(String title) {
         this.title = title;
     }
     public String getTitle() {
         return title;
     }
     public void setValue(String value) {
         this.value = value;
     }
     public String getValue() {
         return value;
     }
 }
 public class TestProducerConsumer {
     public static void main(String[] args) {
         Data data=new Data();
         new Thread(new Producer(data)).start();
         new Thread(new Consumer(data)).start();
     }
 }

数据错乱

 package 多线程;
 class Producer implements Runnable{
     private Data data;
     public Producer(Data data){
         this.data=data;
     }
     @Override
     public void run() {
         for(int i=0;i<50;i++){
             if(i%2==0){
                 this.data.set("饼干","麦香饼干");
             }else{
                 this.data.set("饮料","果汁好喝");
             }
         }
     }
 }
 class Consumer implements Runnable{
     private Data data;
     public Consumer(Data data){
         this.data=data;
     }
     @Override
     public void run() {
         for(int i=0;i<50;i++){
             System.out.println("消费："+this.data.get());
         }
     }
 }
 class Data{
     private String title;
     private String value;
     public synchronized void set(String title,String value) {
         //若不加synchronized仍会有数据错乱现象
         this.title = title;
         try {
             Thread.sleep(100);
         } catch (InterruptedException e) {
             e.printStackTrace();
         }
         this.value=value;
     }
     public synchronized String get() {
         try {
             Thread.sleep(100);
         } catch (InterruptedException e) {
             e.printStackTrace();
         }
         return title+"->"+value;
     }
 }
 public class TestProducerConsumer {
     public static void main(String[] args) {
         Data data=new Data();
         new Thread(new Producer(data)).start();
         new Thread(new Consumer(data)).start();
     }
 }

解决错乱，但有重复现象（非奇偶交替）

 package 多线程;
 class Producer implements Runnable{
     private Data data;
     public Producer(Data data){
         this.data=data;
     }
     @Override
     public void run() {
         for(int i=0;i<50;i++){
             if(i%2==0){
                 this.data.set("饼干","麦香饼干");
             }else{
                 this.data.set("饮料","果汁好喝");
             }
         }
     }
 }
 class Consumer implements Runnable{
     private Data data;
     public Consumer(Data data){
         this.data=data;
     }
     @Override
     public void run() {
         for(int i=0;i<50;i++){
             System.out.println("消费："+this.data.get());
         }
     }
 }
 class Data{
     private boolean flag=true;//如果不初始设置为true可能会在第一个消费时取得null
     private String title;
     private String value;
     public synchronized void set(String title,String value) {
         if(this.flag==false)
             try {
                 super.wait();
             } catch (InterruptedException e1) {
                 e1.printStackTrace();
             }
         //若不加synchronized仍会有数据错乱现象
         this.title = title;
         try {
             Thread.sleep(100);
         } catch (InterruptedException e) {
             e.printStackTrace();
         }
         this.value=value;
         this.flag=false;
         super.notify();
     }
     public synchronized String get() {
         if(this.flag==true)
             try {
                 super.wait();
             } catch (InterruptedException e1) {
                 e1.printStackTrace();
             }
         try {
             Thread.sleep(100);
         } catch (InterruptedException e) {
             e.printStackTrace();
         }
         this.flag=true;
         super.notify();
         return title+"->"+value;
     }
 }
 public class TestProducerConsumer {
     public static void main(String[] args) {
         Data data=new Data();
         new Thread(new Producer(data)).start();
         new Thread(new Consumer(data)).start();
     }
 }

解决重复问题