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十.Java 集合

1.Java 实例 – 数组转集合

import java.util.*;
import java.io.*;public class ArrayToCollection{public static void main(String args[]) throws IOException{int n = 5;         // 5 个元素String[] name = new String[n];for(int i = 0; i < n; i++){name[i] = String.valueOf(i);}List<String> list = Arrays.asList(name); System.out.println();for(String li: list){String str = li;System.out.print(str + " ");}}
}

2.Java 实例 – 集合比较

import java.util.Collections;
import java.util.Set;
import java.util.TreeSet;class Main {public static void main(String[] args) {String[] coins = { "Penny", "nickel", "dime", "Quarter", "dollar" };Set<String> set = new TreeSet<String>();for (int i = 0; i < coins.length; i++) {set.add(coins[i]);}System.out.println(Collections.min(set));System.out.println(Collections.min(set, String.CASE_INSENSITIVE_ORDER));for (int i = 0; i <= 10; i++) {System.out.print("-");}System.out.println("");System.out.println(Collections.max(set));System.out.println(Collections.max(set, String.CASE_INSENSITIVE_ORDER));}
}

3.Java 实例 – HashMap遍历

import java.util.*;public class Main {public static void main(String[] args) {HashMap< String, String> hMap = new HashMap< String, String>();hMap.put("1", "1st");hMap.put("2", "2nd");hMap.put("3", "3rd");Collection cl = hMap.values();Iterator itr = cl.iterator();while (itr.hasNext()) {System.out.println(itr.next());}}
}

4.Java 实例 – 集合长度

import java.util.*;public class Main {public static void main(String [] args) {   System.out.println( "集合实例!\n" ); int size;HashSet collection = new HashSet ();String str1 = "Yellow", str2 = "White", str3 = "Green", str4 = "Blue";  Iterator iterator;collection.add(str1);    collection.add(str2);   collection.add(str3);   collection.add(str4);System.out.print("集合数据: ");  iterator = collection.iterator();     while (iterator.hasNext()){System.out.print(iterator.next() + " ");  }System.out.println();size = collection.size();if (collection.isEmpty()){System.out.println("集合是空的");}else{System.out.println( "集合长度: " + size);}System.out.println();}
}

5.Java 实例 – 集合打乱顺序

import java.util.*;public class Main {public static void main(String[] args) {List<Integer> list = new ArrayList<Integer>();for (int i = 0; i < 10; i++)list.add(new Integer(i));System.out.println("打乱前:");System.out.println(list);for (int i = 1; i < 6; i++) {System.out.println("第" + i + "次打乱：");Collections.shuffle(list);System.out.println(list);}}
}

6.Java 实例 – 集合遍历

import java.util.ArrayList;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;public class Main {public static void main(String[] args) {// List集合的遍历listTest();// Set集合的遍历setTest();}private static void setTest() {Set<String> set = new HashSet<String>();set.add("JAVA");set.add("C");set.add("C++");// 重复数据添加失败set.add("JAVA");set.add("JAVASCRIPT");// 使用iterator遍历set集合Iterator<String> it = set.iterator();while (it.hasNext()) {String value = it.next();System.out.println(value);}// 使用增强for循环遍历set集合for(String s: set){System.out.println(s);}}// 遍历list集合private static void listTest() {List<String> list = new ArrayList<String>();list.add("菜");list.add("鸟");list.add("教");list.add("程");list.add("www.runoob.com");// 使用iterator遍历Iterator<String> it = list.iterator();while (it.hasNext()) {String value = it.next();System.out.println(value);}// 使用传统for循环进行遍历for (int i = 0, size = list.size(); i < size; i++) {String value = list.get(i);System.out.println(value);}// 使用增强for循环进行遍历for (String value : list) {System.out.println(value);}}
}

7.Java 实例 – 集合反转

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.ListIterator;class Main {public static void main(String[] args) {String[] coins = { "A", "B", "C", "D", "E" };List l = new ArrayList();for (int i = 0; i < coins.length; i++)l.add(coins[i]);ListIterator liter = l.listIterator();System.out.println("反转前");while (liter.hasNext())System.out.println(liter.next());Collections.reverse(l);liter = l.listIterator();System.out.println("反转后");while (liter.hasNext())System.out.println(liter.next());}
}

8.Java 实例 – 删除集合中指定元素

import java.util.*;public class Main {public static void main(String [] args) {   System.out.println( "集合实例!\n" ); int size;HashSet collection = new HashSet ();String str1 = "Yellow", str2 = "White", str3 = "Green", str4 = "Blue";  Iterator iterator;collection.add(str1);    collection.add(str2);   collection.add(str3);   collection.add(str4);System.out.print("集合数据: ");  iterator = collection.iterator();     while (iterator.hasNext()){System.out.print(iterator.next() + " ");  }System.out.println();collection.remove(str2);System.out.println("删除之后 [" + str2 + "]\n");System.out.print("现在集合的数据是: ");iterator = collection.iterator();     while (iterator.hasNext()){System.out.print(iterator.next() + " ");  }System.out.println();size = collection.size();System.out.println("集合大小: " + size + "\n");}
}

9.Java 实例 – 只读集合

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;public class Main {public static void main(String[] argv) throws Exception {List stuff = Arrays.asList(new String[] { "a", "b" });List list = new ArrayList(stuff);list = Collections.unmodifiableList(list);try {list.set(0, "new value");} catch (UnsupportedOperationException e) {}Set set = new HashSet(stuff);set = Collections.unmodifiableSet(set);Map map = new HashMap();map = Collections.unmodifiableMap(map);System.out.println("集合现在是只读");}
}

10.Java 实例 – 集合输出

import java.util.*;public class Main{public static void main(String[] args) {System.out.println("TreeMap 实例！\n");TreeMap tMap = new TreeMap();tMap.put(1, "Sunday");tMap.put(2, "Monday");tMap.put(3, "Tuesday");tMap.put(4, "Wednesday");tMap.put(5, "Thursday");tMap.put(6, "Friday");tMap.put(7, "Saturday");System.out.println("TreeMap 键：" + tMap.keySet());System.out.println("TreeMap 值：" + tMap.values());System.out.println("键为 5 的值为: " + tMap.get(5)+ "\n");System.out.println("第一个键: " + tMap.firstKey() + " Value: " + tMap.get(tMap.firstKey()) + "\n");System.out.println("最后一个键: " + tMap.lastKey() + " Value: "+ tMap.get(tMap.lastKey()) + "\n");System.out.println("移除第一个数据: " + tMap.remove(tMap.firstKey()));System.out.println("现在 TreeMap 键为: " + tMap.keySet());System.out.println("现在 TreeMap 包含: " + tMap.values() + "\n");System.out.println("移除最后一个数据: " + tMap.remove(tMap.lastKey()));System.out.println("现在 TreeMap 键为: " + tMap.keySet());System.out.println("现在 TreeMap 包含: " + tMap.values());}
}

11.Java 实例 – 集合转数组

import java.util.*;public class Main{public static void main(String[] args){List<String> list = new ArrayList<String>();list.add("菜"); list.add("鸟"); list.add("教");list.add("程");list.add("www.runoob.com");String[] s1 = list.toArray(new String[0]); for(int i = 0; i < s1.length; ++i){String contents = s1[i];System.out.print(contents);} }
}

12.Java 实例 – List 循环移动元素

import java.util.*;public class Main {public static void main(String[] args) {List list = Arrays.asList("one Two three Four five six".split(" "));System.out.println("List :"+list);Collections.rotate(list, 3);System.out.println("rotate: " + list);}
}

13.Java 实例 – 查找 List 中的最大最小值

import java.util.*;public class Main {public static void main(String[] args) {List list = Arrays.asList("one Two three Four five six one three Four".split(" "));System.out.println(list);System.out.println("最大值: " + Collections.max(list));System.out.println("最小值: " + Collections.min(list));}
}

14.Java 实例 – 遍历 HashTable 的键值

import java.util.Enumeration;
import java.util.Hashtable;public class Main {public static void main(String[] args) {Hashtable ht = new Hashtable();ht.put("1", "One");ht.put("2", "Two");ht.put("3", "Three");Enumeration e = ht.keys();while (e.hasMoreElements()){System.out.println(e.nextElement());}}
}

15.Java 实例 – 使用 Enumeration 遍历 HashTable

import java.util.Enumeration;
import java.util.Hashtable;public class Main {public static void main(String[] args) {Hashtable ht = new Hashtable();ht.put("1", "One");ht.put("2", "Two");ht.put("3", "Three");Enumeration e = ht.elements();while(e.hasMoreElements()){System.out.println(e.nextElement());}}
}

16.Java 实例 – 集合中添加不同类型元素

import java.util.Map;
import java.util.Set;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.TreeMap;
import java.util.TreeSet;import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedHashSet;
import java.util.LinkedList;
import java.util.List;public class Main {public static void main(String[] args) {List lnkLst = new LinkedList();lnkLst.add("element1");lnkLst.add("element2");lnkLst.add("element3");lnkLst.add("element4");displayAll(lnkLst);List aryLst = new ArrayList();aryLst.add("x");aryLst.add("y");aryLst.add("z");aryLst.add("w");displayAll(aryLst);Set hashSet = new HashSet();hashSet.add("set1");hashSet.add("set2");hashSet.add("set3");hashSet.add("set4");displayAll(hashSet);SortedSet treeSet = new TreeSet();treeSet.add("1");treeSet.add("2");treeSet.add("3");treeSet.add("4");displayAll(treeSet);LinkedHashSet lnkHashset = new LinkedHashSet();lnkHashset.add("one");lnkHashset.add("two");lnkHashset.add("three");lnkHashset.add("four");displayAll(lnkHashset);Map map1 = new HashMap();map1.put("key1", "J");map1.put("key2", "K");map1.put("key3", "L");map1.put("key4", "M");displayAll(map1.keySet());displayAll(map1.values());SortedMap map2 = new TreeMap();map2.put("key1", "JJ");map2.put("key2", "KK");map2.put("key3", "LL");map2.put("key4", "MM");displayAll(map2.keySet());displayAll(map2.values());LinkedHashMap map3 = new LinkedHashMap();map3.put("key1", "JJJ");map3.put("key2", "KKK");map3.put("key3", "LLL");map3.put("key4", "MMM");displayAll(map3.keySet());displayAll(map3.values());}static void displayAll(Collection col) {Iterator itr = col.iterator();while (itr.hasNext()) {String str = (String) itr.next();System.out.print(str + " ");}System.out.println();}
}

17.Java 实例 – List 元素替换

import java.util.*;public class Main {public static void main(String[] args) {List list = Arrays.asList("one Two three Four five six one three Four".split(" "));System.out.println("List :"+list);Collections.replaceAll(list, "one", "hundrea");System.out.println("replaceAll: " + list);}
}

18.Java 实例 – List 截取

import java.util.*;public class Main {public static void main(String[] args) {List list = Arrays.asList("one Two three Four five six one three Four".split(" "));System.out.println("List :"+list);List sublist = Arrays.asList("three Four".split(" "));System.out.println("子列表 :"+sublist);System.out.println("indexOfSubList: "+ Collections.indexOfSubList(list, sublist));System.out.println("lastIndexOfSubList: "+ Collections.lastIndexOfSubList(list, sublist));}
}

十一.Java 网络实例

1.Java 实例 – 获取指定主机的IP地址

import java.net.InetAddress;
import java.net.UnknownHostException;public class GetIP {public static void main(String[] args) {InetAddress address = null;try {address = InetAddress.getByName("www.runoob.com");}catch (UnknownHostException e) {System.exit(2);}System.out.println(address.getHostName() + "=" + address.getHostAddress());System.exit(0);}
}

2.Java 实例 – 查看端口是否已使用

import java.net.*;
import java.io.*;public class Main {public static void main(String[] args) {Socket Skt;String host = "localhost";if (args.length > 0) {host = args[0];}for (int i = 0; i < 1024; i++) {try {System.out.println("查看 "+ i);Skt = new Socket(host, i);System.out.println("端口 " + i + " 已被使用");}catch (UnknownHostException e) {System.out.println("Exception occured"+ e);break;}catch (IOException e) {}}}
}

3.Java 实例 – 获取本机ip地址及主机名

import java.net.InetAddress;
import java.net.UnknownHostException;public class NetworkInfo {public static void main(String[] args) {try {// 获取本地主机对象InetAddress localHost = InetAddress.getLocalHost();// 获取主机名String hostName = localHost.getHostName();System.out.println("主机名: " + hostName);// 获取IP地址String hostAddress = localHost.getHostAddress();System.out.println("IP地址: " + hostAddress);} catch (UnknownHostException e) {System.err.println("无法获取本机IP地址及主机名: " + e.getMessage());e.printStackTrace();}}
}

4.Java 实例 – 获取远程文件大小

import java.net.URL;
import java.net.URLConnection;public class Main {public static void main(String[] args) throws Exception {int size;URL url = new URL("http://www.runoob.com/wp-content/themes/runoob/assets/img/newlogo.png");URLConnection conn = url.openConnection();size = conn.getContentLength();if (size < 0)System.out.println("无法获取文件大小。");elseSystem.out.println("文件大小为：" + size + " bytes");conn.getInputStream().close();}
}

5.Java 实例 – Socket 实现多线程服务器程序

import java.io.*;
import java.net.*;public class MultiThreadedServer {public static void main(String[] args) {int port = 12345; // 定义服务器端口try (ServerSocket serverSocket = new ServerSocket(port)) {System.out.println("服务器已启动，等待客户端连接...");while (true) {Socket clientSocket = serverSocket.accept(); // 接受客户端连接System.out.println("客户端已连接: " + clientSocket.getInetAddress().getHostAddress());// 为每个客户端连接启动一个新的线程ClientHandler clientHandler = new ClientHandler(clientSocket);new Thread(clientHandler).start();}} catch (IOException e) {e.printStackTrace();}}
}class ClientHandler implements Runnable {private Socket clientSocket;public ClientHandler(Socket socket) {this.clientSocket = socket;}@Overridepublic void run() {try (InputStream input = clientSocket.getInputStream();OutputStream output = clientSocket.getOutputStream();BufferedReader reader = new BufferedReader(new InputStreamReader(input));PrintWriter writer = new PrintWriter(output, true)) {String clientMessage;while ((clientMessage = reader.readLine()) != null) {System.out.println("收到客户端消息: " + clientMessage);writer.println("服务器回应: " + clientMessage); // 发送回应消息给客户端}} catch (IOException e) {e.printStackTrace();} finally {try {clientSocket.close();} catch (IOException e) {e.printStackTrace();}}}
}

6.Java 实例 – 查看主机指定文件的最后修改时间

import java.net.URL;
import java.net.URLConnection;
import java.util.Date;
import java.text.SimpleDateFormat;public class Main {public static void main(String[] argv) throws Exception {URL u = new URL("http://127.0.0.1/test/test.html");URLConnection uc = u.openConnection();SimpleDateFormat ft = new SimpleDateFormat ("yyyy-MM-dd hh:mm:ss");uc.setUseCaches(false);long timestamp = uc.getLastModified();System.out.println("test.html 文件最后修改时间 :" + ft.format(new Date(timestamp)));}
}

7.Java 实例 – 使用 Socket 连接到指定主机

import java.net.InetAddress;
import java.net.Socket;public class WebPing {public static void main(String[] args) {try {InetAddress addr;Socket sock = new Socket("www.runoob.com", 80);addr = sock.getInetAddress();System.out.println("连接到 " + addr);sock.close();} catch (java.io.IOException e) {System.out.println("无法连接 " + args[0]);System.out.println(e);}}
}

8.Java 实例 – 网页抓取

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.InputStreamReader;
import java.net.URL;public class Main {public static void main(String[] args) throws Exception {URL url = new URL("http://www.runoob.com");BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));BufferedWriter writer = new BufferedWriter(new FileWriter("data.html"));String line;while ((line = reader.readLine()) != null) {System.out.println(line);writer.write(line);writer.newLine();}reader.close();writer.close();}
}

9.Java 实例 – 获取 URL响应头的日期信息

import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Date;public class Main{public static void main(String args[]) throws Exception {URL url = new URL("http://www.runoob.com");HttpURLConnection httpCon = (HttpURLConnection) url.openConnection();long date = httpCon.getDate();if (date == 0)System.out.println("无法获取信息。");elseSystem.out.println("Date: " + new Date(date));}
}

10.Java 实例 – 获取 URL 响应头信息

import java.io.IOException;
import java.net.URL;
import java.net.URLConnection;
import java.util.Map;
import java.util.Set;public class Main {public static void main(String[] args) throws IOException{URL url = new URL("http://www.runoob.com");URLConnection conn = url.openConnection();Map headers = conn.getHeaderFields();Set<String> keys = headers.keySet();for( String key : keys ){String val = conn.getHeaderField(key);System.out.println(key+"    "+val);}System.out.println( conn.getLastModified() );}
}

11.Java 实例 – 解析 URL

import java.net.URL;public class Main {public static void main(String[] args) throws Exception {URL url = new URL("http://www.runoob.com/html/html-tutorial.html");System.out.println("URL 是 " + url.toString());System.out.println("协议是 " + url.getProtocol());System.out.println("文件名是 " + url.getFile());System.out.println("主机是 " + url.getHost());System.out.println("路径是 " + url.getPath());System.out.println("端口号是 " + url.getPort());System.out.println("默认端口号是 " + url.getDefaultPort());}
}

12.Java 实例 – ServerSocket 和 Socket 通信实例

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.net.ServerSocket;
import java.net.Socket;public class Server {public static void main(String[] args) {try {ServerSocket ss = new ServerSocket(8888);System.out.println("启动服务器....");Socket s = ss.accept();System.out.println("客户端:"+s.getInetAddress().getLocalHost()+"已连接到服务器");BufferedReader br = new BufferedReader(new InputStreamReader(s.getInputStream()));//读取客户端发送来的消息String mess = br.readLine();System.out.println("客户端："+mess);BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(s.getOutputStream()));bw.write(mess+"\n");bw.flush();} catch (IOException e) {e.printStackTrace();}}
}

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.Socket;
import java.net.UnknownHostException;public class Client {public static void main(String[] args) {try {Socket s = new Socket("127.0.0.1",8888);//构建IOInputStream is = s.getInputStream();OutputStream os = s.getOutputStream();BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));//向服务器端发送一条消息bw.write("测试客户端和服务器通信，服务器接收到消息返回到客户端\n");bw.flush();//读取服务器返回的消息BufferedReader br = new BufferedReader(new InputStreamReader(is));String mess = br.readLine();System.out.println("服务器："+mess);} catch (UnknownHostException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}}
}

十二.Java 线程

1.Java 实例 – 查看线程是否存活

public class TwoThreadAlive extends Thread {public void run() {for (int i = 0; i < 10; i++) {printMsg();}}public void printMsg() {Thread t = Thread.currentThread();String name = t.getName();System.out.println("name=" + name);}public static void main(String[] args) {TwoThreadAlive tt = new TwoThreadAlive();tt.setName("Thread");System.out.println("before start(), tt.isAlive()=" + tt.isAlive());tt.start();System.out.println("just after start(), tt.isAlive()=" + tt.isAlive());for (int i = 0; i < 10; i++) {tt.printMsg();}System.out.println("The end of main(), tt.isAlive()=" + tt.isAlive());}
}

2.Java 实例 – 获取当前线程名称

public class TwoThreadGetName extends Thread {public void run() {for (int i = 0; i < 10; i++) {printMsg();}}public void printMsg() {Thread t = Thread.currentThread();String name = t.getName();System.out.println("name=" + name);} public static void main(String[] args) {TwoThreadGetName tt = new TwoThreadGetName();tt.start();for (int i = 0; i < 10; i++) {tt.printMsg();}}
}

3.Java 实例 – 状态监测

class MyThread extends Thread{boolean waiting= true;boolean ready= false;MyThread() {}public void run() {String thrdName = Thread.currentThread().getName();System.out.println(thrdName + " starting.");while(waiting) System.out.println("waiting:"+waiting); System.out.println("waiting...");startWait(); try {Thread.sleep(1000);}catch(Exception exc) {System.out.println(thrdName + " interrupted.");}System.out.println(thrdName + " terminating.");}synchronized void startWait() {try {while(!ready) wait();}catch(InterruptedException exc) {System.out.println("wait() interrupted");}}synchronized void notice() {ready = true;notify();}
}
public class Main {public static void main(String args[]) throws Exception{MyThread thrd = new MyThread();thrd.setName("MyThread #1");showThreadStatus(thrd);thrd.start();Thread.sleep(50);showThreadStatus(thrd);thrd.waiting = false;Thread.sleep(50); showThreadStatus(thrd);thrd.notice();Thread.sleep(50);showThreadStatus(thrd);while(thrd.isAlive()) System.out.println("alive");showThreadStatus(thrd);}static void showThreadStatus(Thread thrd) {System.out.println(thrd.getName() + "Alive:=" + thrd.isAlive() + " State:=" + thrd.getState());}
}

4.Java 实例 – 线程优先级设置

public class SimplePriorities extends Thread {private int countDown = 5;private volatile double d = 0; public SimplePriorities(int priority) {setPriority(priority);start();}public String toString() {return super.toString() + ": " + countDown;}public void run() {while(true) {for(int i = 1; i < 100000; i++)d = d + (Math.PI + Math.E) / (double)i;System.out.println(this);if(--countDown == 0) return;}}public static void main(String[] args) {new SimplePriorities(Thread.MAX_PRIORITY);for(int i = 0; i < 5; i++)new SimplePriorities(Thread.MIN_PRIORITY);}
}

5.Java 实例 – 死锁及解决方法

import java.util.Date;public class LockTest {public static String obj1 = "obj1";public static String obj2 = "obj2";public static void main(String[] args) {LockA la = new LockA();new Thread(la).start();LockB lb = new LockB();new Thread(lb).start();}
}
class LockA implements Runnable{public void run() {try {System.out.println(new Date().toString() + " LockA 开始执行");while(true){synchronized (LockTest.obj1) {System.out.println(new Date().toString() + " LockA 锁住 obj1");Thread.sleep(3000); // 此处等待是给B能锁住机会synchronized (LockTest.obj2) {System.out.println(new Date().toString() + " LockA 锁住 obj2");Thread.sleep(60 * 1000); // 为测试，占用了就不放}}}} catch (Exception e) {e.printStackTrace();}}
}
class LockB implements Runnable{public void run() {try {System.out.println(new Date().toString() + " LockB 开始执行");while(true){synchronized (LockTest.obj2) {System.out.println(new Date().toString() + " LockB 锁住 obj2");Thread.sleep(3000); // 此处等待是给A能锁住机会synchronized (LockTest.obj1) {System.out.println(new Date().toString() + " LockB 锁住 obj1");Thread.sleep(60 * 1000); // 为测试，占用了就不放}}}} catch (Exception e) {e.printStackTrace();}}
}

6.Java 实例 – 获取线程id

public class Main extends Object implements Runnable {private ThreadID var;public Main(ThreadID v) {this.var = v;}public void run() {try {print("var getThreadID =" + var.getThreadID());Thread.sleep(2000);print("var getThreadID =" + var.getThreadID());} catch (InterruptedException x) {}}private static void print(String msg) {String name = Thread.currentThread().getName();System.out.println(name + ": " + msg);}public static void main(String[] args) {ThreadID tid = new ThreadID();Main shared = new Main(tid);try {Thread threadA = new Thread(shared, "threadA");threadA.start();Thread.sleep(500);Thread threadB = new Thread(shared, "threadB");threadB.start();Thread.sleep(500);Thread threadC = new Thread(shared, "threadC");threadC.start();} catch (InterruptedException x) {}}
}class ThreadID extends ThreadLocal {private int nextID;public ThreadID() {nextID = 10001;}private synchronized Integer getNewID() {Integer id = new Integer(nextID);nextID++;return id;}protected Object initialValue() {print("in initialValue()");return getNewID();}public int getThreadID() {Integer id = (Integer) get();return id.intValue();}private static void print(String msg) {String name = Thread.currentThread().getName();System.out.println(name + ": " + msg);}
}

7.Java 实例 – 线程挂起

public class SleepingThread extends Thread {private int countDown = 5;private static int threadCount = 0;public SleepingThread() {super("" + ++threadCount);start();}public String toString() { return "#" + getName() + ": " + countDown;}public void run() {while (true) {System.out.println(this);if (--countDown == 0)return;try {sleep(100);}catch (InterruptedException e) {throw new RuntimeException(e);}}}public static void main(String[] args) throws InterruptedException {for (int i = 0; i < 5; i++)new SleepingThread().join();System.out.println("线程已被挂起");}
}

8.Java 实例 – 终止线程

public class ThreadInterrupt extends Thread 
{ public void run() { try { sleep(50000);  // 延迟50秒 } catch (InterruptedException e) { System.out.println(e.getMessage()); } } public static void main(String[] args) throws Exception { Thread thread = new ThreadInterrupt(); thread.start(); System.out.println("在50秒之内按任意键中断线程!"); System.in.read(); thread.interrupt(); thread.join(); System.out.println("线程已经退出!"); } 
}

9.Java 实例 – 生产者/消费者问题

/*author by runoob.comProducerConsumerTest.java*/public class ProducerConsumerTest {public static void main(String[] args) {CubbyHole c = new CubbyHole();Producer p1 = new Producer(c, 1);Consumer c1 = new Consumer(c, 1);p1.start(); c1.start();}
}
class CubbyHole {private int contents;private boolean available = false;public synchronized int get() {while (available == false) {try {wait();}catch (InterruptedException e) {}}available = false;notifyAll();return contents;}public synchronized void put(int value) {while (available == true) {try {wait();}catch (InterruptedException e) { } }contents = value;available = true;notifyAll();}
}class Consumer extends Thread {private CubbyHole cubbyhole;private int number;public Consumer(CubbyHole c, int number) {cubbyhole = c;this.number = number;}public void run() {int value = 0;for (int i = 0; i < 10; i++) {value = cubbyhole.get();System.out.println("消费者 #" + this.number+ " got: " + value);}}
}class Producer extends Thread {private CubbyHole cubbyhole;private int number;public Producer(CubbyHole c, int number) {cubbyhole = c;this.number = number;}public void run() {for (int i = 0; i < 10; i++) {cubbyhole.put(i);System.out.println("生产者 #" + this.number + " put: " + i);try {sleep((int)(Math.random() * 100));} catch (InterruptedException e) { }}}
}

10.Java 实例 – 获取线程状态

// Java 程序 - 演示线程状态
class thread implements Runnable 
{ public void run() { //  thread2  - 超时等待try{ Thread.sleep(1500); }  catch (InterruptedException e)  { e.printStackTrace(); } System.out.println("State of thread1 while it called join() method on thread2 -"+ Test.thread1.getState()); try{ Thread.sleep(200); }  catch (InterruptedException e)  { e.printStackTrace(); }      } 
} public class Test implements Runnable 
{ public static Thread thread1; public static Test obj; public static void main(String[] args) { obj = new Test(); thread1 = new Thread(obj); // 创建 thread1，现在是初始状态System.out.println("State of thread1 after creating it - " + thread1.getState()); thread1.start(); // thread1 - 就绪状态System.out.println("State of thread1 after calling .start() method on it - " +  thread1.getState()); } public void run() { thread myThread = new thread(); Thread thread2 = new Thread(myThread); // 创建 thread1，现在是初始状态System.out.println("State of thread2 after creating it - "+ thread2.getState()); thread2.start(); // thread2 - 就绪状态System.out.println("State of thread2 after calling .start() method on it - " +  thread2.getState()); // moving thread1 to timed waiting state try{ //moving - 超时等待Thread.sleep(200); }  catch (InterruptedException e)  { e.printStackTrace(); } System.out.println("State of thread2 after calling .sleep() method on it - "+  thread2.getState() ); try { // 等待 thread2 终止thread2.join(); }  catch (InterruptedException e)  { e.printStackTrace(); } System.out.println("State of thread2 when it has finished it's execution - " +  thread2.getState()); } }

11.Java 实例 – 获取所有线程

public class Main extends Thread {public static void main(String[] args) {Main t1 = new Main();t1.setName("thread1");t1.start();ThreadGroup currentGroup = Thread.currentThread().getThreadGroup();int noThreads = currentGroup.activeCount();Thread[] lstThreads = new Thread[noThreads];currentGroup.enumerate(lstThreads);for (int i = 0; i < noThreads; i++)System.out.println("线程号：" + i + " = " + lstThreads[i].getName());}
}

12.Java 实例 – 查看线程优先级

public class Main extends Object {private static Runnable makeRunnable() {Runnable r = new Runnable() {public void run() {for (int i = 0; i < 5; i++) {Thread t = Thread.currentThread();System.out.println("in run() - priority="+ t.getPriority()+ ", name=" + t.getName());try {Thread.sleep(2000);}catch (InterruptedException x) {}}}};return r;}public static void main(String[] args) {System.out.println("in main() - Thread.currentThread().getPriority()=" + Thread.currentThread().getPriority());System.out.println("in main() - Thread.currentThread().getName()="+ Thread.currentThread().getName());Thread threadA = new Thread(makeRunnable(), "threadA");threadA.start();try {Thread.sleep(3000);}catch (InterruptedException x) {}System.out.println("in main() - threadA.getPriority()="+ threadA.getPriority());}
}

13.Java 实例 – 中断线程

public class Main extends Object 
implements Runnable {public void run() {try {System.out.println("in run() - 将运行 work2() 方法");work2();System.out.println("in run() - 从 work2() 方法回来");}catch (InterruptedException x) {System.out.println("in run() - 中断 work2() 方法");return;}System.out.println("in run() - 休眠后执行");System.out.println("in run() - 正常离开");}public void work2() throws InterruptedException {while (true) {if (Thread.currentThread().isInterrupted()) {System.out.println("C isInterrupted()=" + Thread.currentThread().isInterrupted());Thread.sleep(2000);System.out.println("D isInterrupted()=" + Thread.currentThread().isInterrupted());}}}public void work() throws InterruptedException {while (true) {for (int i = 0; i < 100000; i++) {int j = i * 2;}System.out.println("A isInterrupted()=" + Thread.currentThread().isInterrupted());if (Thread.interrupted()) {System.out.println("B isInterrupted()=" + Thread.currentThread().isInterrupted());throw new InterruptedException();}}}public static void main(String[] args) {Main si = new Main();Thread t = new Thread(si);t.start();try {Thread.sleep(2000);}catch (InterruptedException x) {}System.out.println("in main() - 中断其他线程");t.interrupt();System.out.println("in main() - 离开");}
}