题目:有三个线程分别打印A、B、C,请用多线程编程实现,在屏幕上循环打印10次ABCABC…
方法一:使用wait()、notify()控制打印次序
public class Test {
public static Object a = new Object();
public static Object b = new Object();
public static Object c = new Object();
public class Runner1 implements Runnable {
public void run() {
for (int i = 0; i < 10; i++) {
try {
synchronized (a) {
// System.out.println("a is locked by t1");
synchronized (b) {
// System.out.println("b is locked by t1");
System.out.print("A");
b.notify();
// System.out.println("t1 notify b");
}
if (i < 9) {
a.wait();
}
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
public class Runner2 implements Runnable {
public void run() {
for (int i = 0; i < 10; i++) {
try {
synchronized (b) {
// System.out.println("b is locked by t2");
synchronized (c) {
// System.out.println("c is locked by t2");
System.out.print("B");
c.notify();
// System.out.println("t2 notify c");
}
if (i < 9) {
b.wait();
}
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
public class Runner3 implements Runnable {
public void run() {
for (int i = 0; i < 10; i++) {
try {
synchronized (c) {
// System.out.println("c is locked by t3");
synchronized (a) {
// System.out.println("a is locked by t3");
System.out.print("C");
a.notify();
// System.out.println("t3 notify a");
}
if (i < 9) {
c.wait();
}
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
public static void main(String[] args) {
Test t = new Test();
Thread t1 = new Thread(t.new Runner1(), "t1");
Thread t2 = new Thread(t.new Runner2(), "t2");
Thread t3 = new Thread(t.new Runner3(), "t3");
t1.start();
try {
Thread.sleep(1);
} catch (InterruptedException e1) {
e1.printStackTrace();
}
t2.start();
try {
Thread.sleep(1);
} catch (InterruptedException e) {
e.printStackTrace();
}
t3.start();
}
}
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方法二:使用管道流在进程间传递消息控制打印次序
import java.io.*;
class RunnerA implements Runnable{
DataInputStream disA=null;
DataOutputStream dosA=null;
public RunnerA(PipedInputStream pisA,PipedOutputStream posA){
disA=new DataInputStream(pisA);
dosA=new DataOutputStream(posA);
}
public void run(){
try{
for(int i=0;i<10;i++){
if(i==0){
System.out.print("A");
dosA.writeChar('A');
}else if(i==9){
char c=disA.readChar();
System.out.print("A");
dosA.writeChar('O');
}else{
char c=disA.readChar();
System.out.print("A");
dosA.writeChar('A');
}
}
}catch(IOException e){
e.printStackTrace();
}
}
}
class RunnerB implements Runnable{
DataInputStream disB=null;
DataOutputStream dosB=null;
public RunnerB(PipedInputStream pisB,PipedOutputStream posB){
disB=new DataInputStream(pisB);
dosB=new DataOutputStream(posB);
}
public void run(){
try{
char c=disB.readChar();
while(true){
if(c=='O'){
System.out.print("B");
dosB.writeChar('O');
break;
}
if(c=='A'){
System.out.print("B");
dosB.writeChar('B');
c=disB.readChar();
}
}
}catch(IOException e){
e.printStackTrace();
}
}
}
class RunnerC implements Runnable{
DataInputStream disC=null;
DataOutputStream dosC=null;
public RunnerC(PipedInputStream pisC,PipedOutputStream posC){
disC=new DataInputStream(pisC);
dosC=new DataOutputStream(posC);
}
public void run(){
try{
char c=disC.readChar();
while(true){
if(c=='O'){
System.out.print("C");
break;
}
if(c=='B'){
System.out.print("C");
dosC.writeChar('C');
c=disC.readChar();
}
}
}catch(IOException e){
e.printStackTrace();
}
}
}
public class Test{
public static void main(String[] args){
PipedOutputStream posA=new PipedOutputStream();
PipedInputStream pisA=new PipedInputStream();
PipedOutputStream posB=new PipedOutputStream();
PipedInputStream pisB=new PipedInputStream();
PipedOutputStream posC=new PipedOutputStream();
PipedInputStream pisC=new PipedInputStream();
try{
pisA.connect(posC);
pisB.connect(posA);
pisC.connect(posB);
}catch(IOException e){
e.printStackTrace();
}
Thread ta=new Thread(new RunnerA(pisA,posA),"ta");
Thread tb=new Thread(new RunnerB(pisB,posB),"tb");
Thread tc=new Thread(new RunnerC(pisC,posC),"tc");
ta.start();
tb.start();
tc.start();
}
}
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