经常面试的时候，让写各种乱七八糟的多线程面试题，收集了很多，有些还是挺好玩的。
1、编写程序实现,子线程循环10次,接着主线程循环20次,接着再子线程循环10次,主线程循环20次,如此反复,循环50次.
package com.zhikui.interview;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
/**@autor http://www.cnblogs.com/fingerboy/p/5352880.html
* @method 编写程序实现,子线程循环10次,接着主线程循环20次,接着再子线程循环10次,主线程循环20次,如此反复,循环50次.
*/
public class interviewTest1{
public static void main(String[] args) {
final Function fc= new Function();
//子线程
new Thread(new Runnable() {
@Override
public void run() {
for(int i =0;i<50;i++){
fc.sub();
}
}
}).start();
//主线程
for(int i =0;i<50;i++){
fc.main();
}
}
}
class Function {
private boolean flag = false;
//Lock lock=new ReentrantLock();
// Condition con=lock.newCondition();
//子线程实现
public synchronized void sub(){
while(flag){
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
for(int i =0;i<10;i++){
System.out.println("[sub]"+i);
}
flag = true;
this.notify();
}
//主线程实现
public synchronized void main(){
while(!flag){
try {
this.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
for(int i =0;i<20;i++){
System.out.println("[main]"+i);
}
flag = false;
this.notify();
}
}
2、设计四个线程,其中两个线程每次对变量i加1,另外两个线程每次对i减1.
package com.zhikui.interview;
/**
* @methord设计四个线程,其中两个线程每次对变量i加1,另外两个线程每次对i减1.
* @author http://www.cnblogs.com/fingerboy/p/5352880.html
*
*/
public class interviewTest2 {
private int i = 0;
public static void main(String[] args) {
//执行线程
interviewTest2 it = new interviewTest2();
Add add = it.new Add();
Sub sub = it.new Sub();
for(int i=1;i<=2;i++){
new Thread(add,"线程"+i).start();
new Thread(sub,"线程"+i).start();
}
}
class Add implements Runnable {
@Override
public void run() {
for(int j=0;j<10;j++){
addOne();
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
class Sub implements Runnable{
@Override
public void run() {
for(int j=0;j<10;j++){
subOne();
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
public synchronized void addOne(){
i++;
System.out.println(Thread.currentThread().getName()+"[加一的值为]"+i);
}
public synchronized void subOne(){
i--;
System.out.println(Thread.currentThread().getName()+"[减一的值为]"+i);
}
}
3、T2 T3三个线程，怎样保证T2在T1执行完之后执行 T3在T2执行完之后执行
package com.zhikui.interview;
/**
* @methor现在有T1 T2 T3三个线程，怎样保证T2在T1执行完之后执行 T3在T2执行完之后执行
* @author http://blog.csdn.net/caohaicheng/article/details/38071097
*
*/
public class interviewTest3 {
public static void main(String[] args) {
interviewTest3 it = new interviewTest3();
T1 t1 = it.new T1("t1");
T1 t2 = it.new T1("t2");
T1 t3 = it.new T1("t3");
t1.start();
try {
t1.join();
} catch (Exception e) {
e.printStackTrace();
}
t2.start();
try {
t2.join();
} catch (Exception e) {
e.printStackTrace();
}
t3.start();
try {
t3.join();
} catch (Exception e) {
e.printStackTrace();
}
}
class T1 extends Thread{
private String name;
public T1(String name){
this.name = name;
}
@Override
public void run(){
for(int i=0;i<5;i++){
try {
sleep(5);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(this.name+"循环"+i);
}
}
}
class T2 extends Thread{
private String name;
public T2(String name){
this.name = name;
}
@Override
public void run(){
for(int i=0;i<5;i++){
try {
sleep(5);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(this.name+"循环"+i);
}
}
}
class T3 extends Thread{
private String name;
public T3(String name){
this.name = name;
}
@Override
public void run(){
for(int i=0;i<5;i++){
try {
sleep(5);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(this.name+"循环"+i);
}
}
}
}
4、写一个死锁的例子
package com.zhikui.interview;
/**
* 写一个死锁的例子
* @author author
*/
public class interviewTest4 {
private static Object A = new Object();
private static Object B = new Object();
public static void main(String[] args) {
//第一个线程
new Thread(new Runnable() {
@Override
public void run() {
while(true){
synchronized (A) {
synchronized (B) {
System.out.println("死锁A");
}
}
}
}
},"T1").start();
//第二个线程
new Thread(new Runnable() {
@Override
public void run() {
while(true){
synchronized (B) {
synchronized (A) {
System.out.println("死锁B");
}
}
}
}
},"T1").start();
}
}
5、两个线程，一个线程输出1，一个线程输出2，循环输出
package com.zhikui.interview;
/**
* @methor两个线程，一个线程输出1，一个线程输出2，循环输出
* @author http://blog.csdn.net/fufengrui/article/details/30232603
*
*/
public class interviewTest5 {
public static void main(String[] args) {
OneThread one = new OneThread();
TwoThread two = new TwoThread();
one.start();
two.start();
}
}
class OneThread extends Thread {
@Override
public void run() {
synchronized (interviewTest5.class) {
while (true) {
System.out.println("1");
try {
interviewTest5.class.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
interviewTest5.class.notify();
}
}
}
}
class TwoThread extends Thread {
@Override
public void run() {
synchronized (interviewTest5.class) {
while (true) {
System.out.println("2");
interviewTest5.class.notify();
try {
interviewTest5.class.wait();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
}
}
6、有1-26个数字和a-z字母,用Java多线程实现先输出2和数字再输出2个字母
package com.zhikui.interview;
/**
* 有1-26个数字和a-z字母,用Java多线程实现先输出2和数字再输出2个字母
*
* @author https://zhidao.baidu.com/question/201633880.html
*
*/
public class interviewTest6 {
public static void main(String[] args) {
Print p = new Print();
new numThread(p).start();
new charThread(p).start();
}
}
class Print {
boolean boo = true;
char ch = ‘A‘;
int num = 1;
public synchronized void printNum() {
if (boo) {
try {
wait();
} catch (Exception e) {
}
System.out.print(num++);
System.out.print(num++);
}
boo = false;
notify();
if (num == 52)
num++;
}
public synchronized void printChar() {
if (!boo) {
try {
wait();
} catch (Exception e) {
}
System.out.print(ch++);
System.out.print(ch++);
}
boo = true;
notify();
}
}
class numThread extends Thread {
Print p = null;
public numThread(Print p) {
this.p = p;
}
public void run() {
while (p.num <= 53)
p.printNum();
}
}
class charThread extends Thread {
Print p = null;
public charThread(Print p) {
this.p = p;
}
public void run() {
while (p.ch <= ‘Z‘)
p.printChar();
}
}
时间： 2024-12-20 08:58:06