bomberlhl

synchronized(欲同步的对象obj) {
需要同步的代码块
}

public class HelloSynchronized {
public static void main(String[] args) {
//
HelloSynchronized helloSynchronized = new HelloSynchronized();
//创建2个线程t1, t2，分别调用HelloSynchronized helloSynchronized的2个方法method1，与method2
Thread t1 = new Thread(new HelloSynchronizedRunnalbe(helloSynchronized, "method1"), "t1");
Thread t2 = new Thread(new HelloSynchronizedRunnalbe(helloSynchronized, "method2"), "t2");
t1.start();
t2.start();
}
//synchronized public void method1() {    //同步方法
public void method1() {
synchronized (this) {    //同步块
System.out.println(Thread.currentThread().getName()
+ " enter method1");
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
// do nothing
}
System.out.println(Thread.currentThread().getName()
+ " exit method1");
}
}
//synchronized public void method2() {    //同步方法
public void method2() {
synchronized (this) {    //同步块
System.out.println(Thread.currentThread().getName()
+ " enter method2");
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
// do nothing
}
System.out.println(Thread.currentThread().getName()
+ " exit method2");
}
}
}
class HelloSynchronizedRunnalbe implements Runnable {
private HelloSynchronized helloSynchronized;
private String methodName;
public HelloSynchronizedRunnalbe(HelloSynchronized helloSynchronized, String methodName) {
this.helloSynchronized = helloSynchronized;
this.methodName = methodName;
}
public void run() {
if (methodName.equals("method1")) {
helloSynchronized.method1();
} else if (methodName.equals("method2")) {
helloSynchronized.method2();
}
}
}

synchronized private void sellBook(Book book) {
...
}

private void sellBook(Book book) {
synchronized(this) {
...
}
}

public class Book {
private String name;
private boolean sold = false;
public Book(String name) {
this.name = name;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public boolean isSold() {
return sold;
}
public void setSold(boolean sold) {
this.sold = sold;
}
}

import java.util.List;
public class SellBookRunnable implements Runnable {
private String saleMan;
private List<Book> bookList;
public SellBookRunnable(String saleMan, List<Book> bookList) {
this.saleMan = saleMan;
this.bookList = bookList;
}
public void run() {
for (int i = 0; i < bookList.size(); i++) {
Book book = bookList.get(i);
sellBook(book);
}
}
/**
* 售货员卖书。我们这样描述售货员的卖书过程。
*
* @param book Book
*/
private void sellBook(Book book) {
//从开始售书-到售书完成，使用synchronized (book)保证book不被其他售货员售出
synchronized (book) {
if (book.isSold()) {
return;
} else {
try {
//为了让各线程有执行机会，设置平均售书时间为0.5秒
Thread.sleep(500);
} catch (Exception e) {
}
//设置已售标志
book.setSold(true);
//打印该书已售信息
System.out.println("[" + saleMan + "]" + book.getName() + " sold out:"
+ book.isSold() + ". by "
+ Thread.currentThread().getName());
}
}
}
}

import java.util.List;
public class SellBookThread extends Thread {
private String saleMan;
private List<Book> bookList;
public SellBookThread(String saleMan, List<Book> bookList) {
this.saleMan = saleMan;
this.bookList = bookList;
}
public void run() {
for (int i = 0; i < bookList.size(); i++) {
Book book = bookList.get(i);
sellBook(book);
}
}
/**
* 售货员卖书。我们这样描述售货员的卖书过程。
*
* @param book Book
*/
private void sellBook(Book book) {
//从开始售书-到售书完成，使用synchronized (book)保证book不被其他售货员售出
synchronized (book) {
if (book.isSold()) {
return;
} else {
try {
//为了让各线程有执行机会，设置平均售书时间为0.5秒
Thread.sleep(500);
} catch (Exception e) {
}
//设置已售标志
book.setSold(true);
//打印该书已售信息
System.out.println("[" + saleMan + "]" + book.getName() + " sold out:"
+ book.isSold() + ". by "
+ Thread.currentThread().getName());
}
}
}
}

import java.util.ArrayList;
import java.util.List;
//该类调用SellBookXxx类
public class CallSellBook {
/**
* 用线程模拟这个售书的过程
*/
public static void main(String[] args) {
//方法1：
callSellBookThread();
//or
//方法2：
//callSellBookRunnable();
}
//调用SellBookRunnable（Runnable接口实现类）模拟售书过程
public static void callSellBookThread() {
List <Book>bookList = getBookListForSale();
//将预售书籍清单交给售货员SaleMan1
Thread t1 = new SellBookThread("SaleMan1", bookList);
//将预售书籍清单交给售货员SaleMan2
Thread t2 = new SellBookThread("SaleMan2", bookList);
//售货员SaleMan1开始售书
t1.start();
//售货员SaleMan2开始售书
t2.start();
}
//调用SellBookRunnable（Runnable接口实现类）模拟售书过程
public static void callSellBookRunnable() {
List <Book>bookList = getBookListForSale();
//将预售书籍清单交给售货员SaleMan1
Thread t1 = new Thread(new SellBookRunnable("SaleMan1", bookList));
//将预售书籍清单交给售货员SaleMan2
Thread t2 = new Thread(new SellBookRunnable("SaleMan2", bookList));
//售货员SaleMan1开始售书
t1.start();
//售货员SaleMan2开始售书
t2.start();
}
//准备预售书籍
public static List<Book> getBookListForSale() {
List <Book>bookList = new ArrayList();
for (int i = 0; i < 20; i++) {
Book book = new Book("Book" + i);
bookList.add(book);
}
return bookList;
}
}