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1、1.進程和線程有何區(qū)別，Java是如何實現(xiàn)多線程的。
答：區(qū)別：一個程序至少有一個進程,一個進程至少有一個線程；線程的劃分尺度小于進程；進程在執(zhí)行過程中擁有獨立的內存單元，而多個線程共享內存，從而極大地提高了程序的運行效率。
Java程序一般是 繼承Thread 類 或者實現(xiàn) Runnable接口，從而實現(xiàn)多線程。
2.簡述線程的生命周期，重點注意線程阻塞的幾種情況，以及如何重回就緒狀態(tài)。
答：線程的聲明周期：新建-就緒-（阻塞）-運行--死亡
線程阻塞的情況：休眠、進入對象wait池等待、進入對象lock池等待；
休眠時間到回到就緒狀態(tài)；在wait池中獲得notify（）進入lo
2、ck池，然后獲得鎖棋標進入就緒狀態(tài)。
3.隨便選擇兩個城市作為預選旅游目標。實現(xiàn)兩個獨立的線程分別顯示10次城市名，每次顯示后休眠一段隨機時間（1000毫秒以內），哪個先顯示完畢，就決定去哪個城市。分別用Runnable接口和Thread類實現(xiàn)。
（注：兩個類，相同一個測試類）
//Runnable接口實現(xiàn)的線程runable類
public class runnable implements Runnable {
?private String city;
?public runnable() {}
?public runnable(String city) {
? this
3、.city = city;
?}
?public void run() {
? for (int i = 0; i < 10; i++) {??
?? System.out.println(city);
?? try {
??? //休眠1000毫秒。
??? Thread.sleep(1000);
?? } catch (InterruptedException e) {
??? e.printStackTrace();
?? }
? }?
?}
?}
// Thread類實現(xiàn)的線程thread類
public class runnable extends
4、Thread {
?private String city;
?public runnable() {}
?public runnable(String city) {
? this.city = city;
?}
?public void run() {
? for (int i = 0; i < 10; i++) {??
?? System.out.println(city);
?? try {
??? //休眠1000毫秒。
??? Thread.sleep(1000);
?? } catch (InterruptedException e) {
??? e.
5、printStackTrace();
?? }
? }?
?}
?}
?
//test8_3
public class test8_3 {
?public static void main(String[] args) {
??// 將創(chuàng)建一個線程對象，這個對象接受一個實現(xiàn)了Runnable接口。實際上這里也就是使用run()方法
??runnable r1=new runnable("廣州");
??runnable r2=new runnable("烏魯木齊");
??Thread t1 = new Thread(r1);
??Thread t2 = new T
6、hread(r2);
??// 啟動線程
??t1.start();
??t2.start();
?}
}
運行結果分別為：
???
4.編寫一個多線程程序實現(xiàn)如下功能：線程A和線程B分別在屏幕上顯示信息“…start”后，調用wait等待；線程C開始后調用sleep休眠一段時間，然后調用notifyall，使線程A和線程B繼續(xù)運行。線程A和線程B恢復運行后輸出信息“…end”后結束，線程C在判斷線程B和線程A結束后自己結束運行。
//test8_4
public class test8_4 {
?Thread A = new Thread("A") {
7、
??public void run() {
???Wait("A");
??}
?};
?Thread B = new Thread("B") {
??public void run() {
???Wait("B");
??}
?};
?Thread C = new Thread("C") {
??public void run() {
???while (true) {
????if (!A.isAlive() && !B.isAlive())
?????return;
????try {
?????Thread.sleep(2000);
????} ca
8、tch (InterruptedException e) {
?????e.printStackTrace();
????}
????notifyall();
???}
??}
?};
?
?public synchronized void Wait(String name) {
??System.out.println(name + "..start");
??try {
???wait();
??} catch (InterruptedException e) {
???e.printStackTrace();
??}
??System.out.println
9、(name + "..end");
?}
?public synchronized void notifyall() {
??notifyAll();
?}
?public static void main(String args[]) {
??test8_4 test = new test8_4();
??//A、B兩線程一起輸入start和輸出end，不過中間有C讓線程休眠2秒，沒法全部一次性輸出，
??//之后再喚醒，讓AB繼續(xù)輸出下半部分end
??test.A.start();
??test.B.start();
??test.C.start();
?}
}
10、
運行結果：
?
4.
lass test implements Runnable{
public test(){ }
public void run(){
if(Thread.currentThread().getName().equals("A")){
System.out.println("A...start");
synchronized(this)
{
try{
wait();
System.out.println("A...end");
notify();
}catch(Exception e){
11、 }
}
}
else if(Thread.currentThread().getName().equals("B")){
System.out.println("B...start");
synchronized(this){
try{
wait();
System.out.println("B...end");
}catch(Exception e){
}
}
}else if(Thread.currentThread().getName().equals("C")){
try{
Thread.sleep(10);
12、
synchronized(this){
notify();
}
}catch(Exception e){
}
}
}
}
public class d {
public static void main(String args[]) {
test show=new test();
Thread A=new Thread(show,"A");
Thread B=new Thread(show,"B");
Thread C=new Thread(show,"C");
A.start();
B.start();
C.start()
13、;
}
}
5.實現(xiàn)一個數(shù)據(jù)單元，包括學號和姓名兩部分。編寫兩個線程，一個線程往數(shù)據(jù)單元中寫，另一個線程往外讀。要求沒寫一次就往外讀一次。
//Data類
import java.util.Scanner;
public class Data{
?String studentId;
?String name;
?boolean available = false;// 判斷是讀是寫
?Scanner in = new Scanner(System.in);// 定義一個輸入對象
?public synchronized void read()
?{
?
14、?if(available)
???try
???{
????wait();
???}
???catch(Exception e)
???{
????
???}
??System.out.printf("請輸入學號:");
??try
??{
???studentId=in.next();
??}
??catch(Exception e)
??{
???System.out.println("輸入學號出錯！");
??}
??System.out.printf("請輸入姓名:");
??try
??{
???name=in.next();
??}
15、??catch(Exception e)
??{
???System.out.println("輸入姓名出錯！");
??}
??System.out.println();
??available=true;
??notify();
?}
?public synchronized void write()
?{
??if(!available)
???try
???{
????wait();
???}
???catch(Exception e)
???{???
???}
??System.out.println("輸出學生學號："+studentId+" 姓
16、名："+name+"\n");
??available=false;
??notify();
?}
}
//Read類
public class Read extends Thread{
?Data d1 = null;
?public Read(Data d){
??this.d1=d;?
?}
?public void run(){
??while(true)
??{
???d1.read();
??}
?}
}
//Write類
class Write extends Thread{
?Data d2=null;
?public Write(Da
17、ta d)
?{
??this.d2=d;
?}
?public void run()
?{
??while(true)
??{
???d2.write();
??}
?}
}
//test8_5類
public class test8_5 {
?public static void main(String[] args){
??Data data=new Data();
??new Read(data).start();
??new Write(data).start();
??
?}
}
運行結果：
?
6.創(chuàng)建兩個不同優(yōu)先級的線程，都
18、從1數(shù)到10000，看看哪個數(shù)得快。
(注：線程的優(yōu)先級別越高低與執(zhí)行速度沒有絕對關系！)
//Count類
public class Count extends Thread {
?int which;
?int n = 10000;
?public Count(int which){
??this.which=which;?
?}
?public void run() {
??for (int i = 1; i <= n; i++) {
???if (i == n) {
????System.out.println(which+"號進程"+ "結束！");
???
19、}
??}
?}
}
//test8_6
public class test8_6 {
?public static void main(String[] args) {
??Count count1 = new Count(1);
??Count count2 = new Count(2);?
??Thread t1 = new Thread(count1);
??Thread t2 = new Thread(count2);??
??t1.setPriority(2);//1號進程優(yōu)先級是2
??t2.setPriority(8);//2號進程優(yōu)先級是8
??t1
20、.start();
??t2.start();
?}
}
運行結果：
都有可能。
7.編寫一個Java程序，以說明較高優(yōu)先級的線程通過調用sleep方法，使較低優(yōu)先級的線程獲得運行的機會。
（這里可以借鑒課本例8—13）
//TestThread類
public class TestThread extends Thread {
?private int tick = 1;
?private int num;
?public TestThread(int i) {
??this.num = i;
?}
?public void run() {
??while
21、 (tick < 400000) {
???tick++;
???if ((tick % 50000) == 0) {
????System.out.println("Thread #" + num + "，tick =" + tick);
????yield();
????try {
?????sleep(1);
????} catch (Exception e) {
????}
???}
??}
?}
}
//test8_7
public class test8_7 {
?public static void main(String[] args){
??T
22、estThread[] runners = new TestThread[2];
??for(int i=0;i<2;i++){
???runners[i]=new TestThread(i);
??}
??runners[0].setPriority(2);
??runners[1].setPriority(5);
??for(int i=0;i<2;i++){
???runners[i].start();
??}
?
?}
}
運行結果：
?
8.主線程控制新線程的生命，當主線程運行一段時間后，控制新線程死亡，主線程繼續(xù)運行一段時間后結束。
(注：main函數(shù)
23、就是主線程，程序里其他的Thread都屬于子線程。可以參考課本的例8—1)
//SonThread類
public class SonThread extends Thread{
?private int num;
?public SonThread(int num){
??this.num=num;
?}
?public void run(){
??int i=num;
??int result=1;
??System.out.println("new thread start.");
?/*?while(i>0){
???result=result*i;
???i
24、--;
??}*/
??System.out.println("the new thread of "+num+"is "+result);
??System.out.println("new thread ends");
?}
}
//test8_8
public class test8_8 {
?public static void main(String[] args){
??System.out.println("main tread start.");
??SonThread newThread = new SonThread(10);
??newThread.
25、start();
??//；浪費時間的循環(huán)
??int i=1;
??while(i<=100000){
???i++;
??}
??newThread.stop();//結束新進程
??System.out.println("main thread ends");
??
?}
}
運行結果：(這個結果很難把握，通常都會出現(xiàn)2那樣的結果，知道原理就好。)
2
?
9.用兩個線程模擬存、取貨物。一個線程往一對象里放貨物（包括品名、價格），另外一個線程取貨物。分別模擬“放一個、取一個”和“放若干個、取若干個”兩種情況。
//Good貨物類
public cla
26、ss Good {
?String name;
?int price;
?public Good(){
??
?}
?public Good(String name,int price){
??this.name=name;
??this.price=price;
?}
?public Good(Good g){
??this.name=g.name;
??this.price=g.price;?
?}
}
//WareHouse倉庫類
import java.util.ArrayList;
import java.util.List;
import jav
27、a.util.Scanner;
public class WareHouse {
?Good good = null;
?Scanner in = new Scanner(System.in);
?List list = new ArrayList();//用來存放商品對象
?int count;//想存入商品的個數(shù)
?boolean available = true;
?public WareHouse() {
?}
?
?public WareHouse(int count) {
??this.count = count;
?}
?public WareHouse
28、(List list) {
??this.count = count;
??for (int i = 0; i < list.size(); i++) {
???this.list.add((Good) list.get(i));
??}
?}
?public synchronized void saveGood() {
??if (available==false) {
???try {
????wait();
???} catch (InterruptedException e) {
????// TODO Auto-generated catch block
??
29、??e.printStackTrace();
???}
??}??
??for (int i = 0; i < count; i++) {
???String n;
???int p;
???System.out.println("請輸入" + (i+1) + "號商品的名稱：");
???n = in.next();
???System.out.println("價格：");
???p = in.nextInt();
???good = new Good(n, p);
???list.add(good);
??}
??available = false;
??no
30、tify();????
?}
?public synchronized void takeGood() {
??if (available==true) {
???try {
????wait();
???} catch (InterruptedException e) {
????// TODO Auto-generated catch block
????e.printStackTrace();
???}
??}
??for (int i = 0; i < list.size(); i++) {
???good = (Good) list.get(i);
???S
31、ystem.out.print((i+1)+ "號商品的名稱為：" + good.name);
???System.out.println("\t價格為：" + good.price);
??}
??available = true;
??notify();
?}
}
//Save存貨物類
public class Save extends Thread{
?WareHouse wareHouse = null;
?public Save(WareHouse w){
??this.wareHouse=w;?
?}
?public void run(){
??
??
32、?wareHouse.saveGood();??
?}
}
//Take取貨物類
public class Take extends Thread{
?WareHouse wareHouse = null;
?public Take(WareHouse w){
??this.wareHouse=w;?
?}
?public void run(){??
??
???wareHouse.takeGood();??????
?}
}
//test8_9測試類
import java.util.Scanner;
public class test8_9 {
?publ
33、ic static void main(String[] args){??
??Scanner in =new Scanner(System.in);
??System.out.println("請輸入倉庫的容量：");
??int i=in.nextInt();
??WareHouse wareHouse=new WareHouse(i);
??Thread saveGood=new Save(wareHouse);
??Thread takeGood=new Take(wareHouse);
?
??saveGood.start();
??takeGood.start()
34、;?????
?}
}
運行結果：?
10.用兩個線程模擬對話，任何一個線程都可以隨時收發(fā)信息。
(這道題本人搞不清楚，暫且用網上的給大家參考下。
聽說要用到：
Socket.getInputStream()獲取輸入流用于“接收”
Socket.getOutputStream()獲取輸出流用于“發(fā)送”
)
//test8_10
import java.io.*;
import .*;
import java.util.*;
public class test8_10 {
??? public static void main(String[] args
35、) {
??????? try {
??????????? // establish server socket
??????????? ServerSocket s = new ServerSocket(8189);
??????????? // wait for client connection
??????????? Socket incoming = s.accept();
??????????? try {
??????????????? InputStream inStream = incoming.getInputStream();
??????????????
36、? OutputStream outStream = incoming.getOutputStream();
??????????????? Scanner in = new Scanner(inStream);
??????????????? PrintWriter out = new PrintWriter(outStream, true);
??????????????? out.println("Hello! Enter BYE to exit.");
??????????????? // echo client input
??????????????? boolean d
37、one = false;
??????????????? while (!done && in.hasNextLine()) {
??????????????????? String line = in.nextLine();
??????????????????? out.println("Echo: " + line);
??????????????????? if (line.trim().equals("BYE"))
??????????????????????? done = true;
??????????????? }
??????????? } finally {
??????????????? incoming.close();
??????????? }
??????? } catch (IOException e) {
??????????? e.printStackTrace();
??????? }
??? }
}
java第八章答案
