一道经典的面试题目：两个线程，分别打印ab，其中线程a打印a，线程b打印b，各打印10次，使之出现ababababa.. 的效果
package com.shangshe.path;
public class threadab {
/**
* @param args
*/
public static void main(string[] args) {
final print business = new print();
new thread(new runnable() {
public void run() {
for(int i=0;i<10;i++) {
business.print_a();
}
}
}).start();
new thread(new runnable() {
public void run() {
for(int i=0;i<10;i++) {
business.print_b();
}
}
}).start();
}
}
class print {
private boolean flag = true;
public synchronized void print_a () {
while(!flag) {
try {
this.wait();
} catch (interruptedexception e) {
// todo auto-generated catch block
e.printstacktrace();
}
}
system.out.print("a");
flag = false;
this.notify();
}
public synchronized void print_b () {
while(flag) {
try {
this.wait();
} catch (interruptedexception e) {
// todo auto-generated catch block
e.printstacktrace();
}
}
system.out.print("b");
flag = true;
this.notify();
}
}
由上面的例子我们可以设计出3个线程乃至于n个线程的程序，下面给出的例子是3个线程，分别打印a，b，c 10次，使之出现abcabc.. 的效果
public class threadabc {
/**
* @param args
*/
public static void main(string[] args) {
final print business = new print();
new thread(new runnable() {
public void run() {
for(int i=0;i<100;i++) {
business.print_a();
}
}
}).start();
new thread(new runnable() {
public void run() {
for(int i=0;i<100;i++) {
business.print_b();
}
}
}).start();
new thread(new runnable() {
public void run() {
for(int i=0;i<100;i++) {
business.print_c();
}
}
}).start();
}
}
class print {
private boolean should_a = true;
private boolean should_b = false;
private boolean should_c = false;
public synchronized void print_a () {
while(should_b || should_c) {
try {
this.wait();
} catch (interruptedexception e) {
// todo auto-generated catch block
e.printstacktrace();
}
}
system.out.print("a");
should_a = false;
should_b = true;
should_c = false;
this.notifyall();
}
public synchronized void print_b () {
while(should_a || should_c) {
try {
this.wait();
} catch (interruptedexception e) {
// todo auto-generated catch block
e.printstacktrace();
}
}
system.out.print("b");
should_a = false;
should_b = false;
should_c = true;
this.notifyall();
}
public synchronized void print_c () {
while(should_a || should_b) {
try {
this.wait();
} catch (interruptedexception e) {
// todo auto-generated catch block
e.printstacktrace();
}
}
system.out.print("c");
should_a = true;
should_b = false;
should_c = false;
this.notifyall();
}
}
再一次证明了软件工程的重要性了；在多线程程序中，应该说在程序中，我们应该把那些业务逻辑代码放到同一个类中，使之高内聚，低耦合
更多java多线程实现同时输出。