j2me中的线程间同步测试

 notify和wait用于线程间同步，下面是3个简单的例子；

例子一：

public class synObject {private Thread m_synT;Object obj = new Object();public void start(){m_synT = new synT(1);m_synT.start();new synT(2).start();}public void process(){synchronized(obj){obj.notify();}}private class synT extends Thread{int id = 0;public synT(int value){id = value;}public void run(){int iCount = 0;while(true){System.out.println("id:"+id+" run:"+iCount++);try{sleep(100);}catch(InterruptedException ie){}synchronized(obj){try{obj.wait();}catch(InterruptedException ie){System.out.println("ie:"+ie.getMessage());}}}}}} 

在Midlet中，按键触发process，每按一次，循环运行一次；通过Object对象obj控制！

 

例子二：

简单的生产者---消费者问题：一个生产者、一个消费者

public class Queue {int value;boolean bFull = false;public synchronized void put(int i) {//synchronized(this){if (!bFull) {value = i;bFull = true;notify();}try {wait();} catch (Exception e) {e.printStackTrace();}//}}public synchronized int get() { //synchronized(this){if(!bFull) { try { wait(); }catch(Exception e){ e.printStackTrace(); } } bFull=false; notify();//} return value; }} 

生产者：

class Producer extends Thread {Queue q;static int s_id = 0;int m_id = 0;Producer(Queue q) {this.q = q;m_id = s_id++;}public void run() {//synchronized(q){for (int i = 0; i < 100; i++) {q.put(i);System.out.println("id:"+m_id+" Producer put " + i);}//}}} 

消费者：

class Consumer extends Thread {Queue q;static int s_id = 0;int m_id = 0;Consumer(Queue q) {this.q = q;m_id = s_id++;}public void run(){ int value = 0;while(true){//synchronized(q){value = q.get();if(m_id == 1){System.out.println(value);}//System.out.println("id:"+m_id+" Consumer get "+q.get());//}} }} 

 

例子三：多个生产者和多个消费者

public class Queue2 extends Queue{private static final int BUFF_LEN = 2;int[] m_iQueue = new int[BUFF_LEN];int m_iReadIndex = 0;int m_iWriteIndex = 0;private static final int STATE_EMPTY = 0;private static final int STATE_NORMAL = 1;private static final int STATE_FULL = 2;int m_iState = STATE_NORMAL;Object m_objR = new Object();Object m_objW = new Object();public void put(int value){synchronized(m_objW){if(((m_iWriteIndex+1)%BUFF_LEN) == m_iReadIndex){//fullSystem.out.println("full");m_iState = STATE_FULL;try{m_objW.wait();}catch(InterruptedException ie){}}}synchronized(m_objR){m_iWriteIndex = (m_iWriteIndex+1)%BUFF_LEN;m_iQueue[m_iWriteIndex] = value;if(m_iState == STATE_EMPTY){//System.out.println("put notify");m_iState = STATE_NORMAL;m_objR.notify();}}}public int get(){synchronized(m_objR){if(m_iReadIndex == m_iWriteIndex){//emptym_iState = STATE_EMPTY;System.out.println("empty");try{m_objR.wait();}catch(InterruptedException ie){}}}int value = 0;synchronized(m_objW){m_iReadIndex = (m_iReadIndex + 1)%BUFF_LEN;value = m_iQueue[m_iReadIndex];if(m_iState == STATE_FULL){//System.out.println("get notify");m_iState = STATE_NORMAL;m_objW.notify();}}return value;}} 

这时，需要使用两个Object来控制同步，一个用来控制生产者，一个用来控制消费者；