怎么实现多线程

怎样实现多线程

案例：下载工具

一、DownLoadJFrame1.java

package util;import java.awt.Container;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.io.File;import java.io.InputStream;import java.io.RandomAccessFile;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JTextField;public class DownLoadJFrame1 extends JFrame implements ActionListener{// 声明组件private JLabel loadJLable;private JTextField loadJTextField;private JButton lodeJButton;//随机文件private RandomAccessFile accessFile;public DownLoadJFrame1() {     //设置标题super("下载工具");//设置大小this.setSize(400,300);   //设置居中this.setLocationRelativeTo(null);//关闭this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//设置可见性this.setVisible(true);//设置容器对象Container c=this.getContentPane();//设置容器面板c.setLayout(null);//实例化组件loadJLable=new JLabel("下载的地址");loadJTextField=new JTextField("http://localhost:8080/day31/image/ff.jpg");lodeJButton=new JButton("下载");//设置组件位置loadJLable.setBounds(10,20,80,30);loadJTextField.setBounds(90,20,280,30);lodeJButton.setBounds(120,100,100,30);//添加到面板c.add(loadJLable);c.add(loadJTextField);c.add(lodeJButton);//添加监听事件lodeJButton.addActionListener(this);}public static void main(String[] args) {new DownLoadJFrame1();}@Overridepublic void actionPerformed(ActionEvent e) {  lodeJButton.setEnabled(false);  //获取下载的路径  final String path=loadJTextField.getText();  try {  //根据路径创建URL对象URL url=new URL(path);//打开连接HttpURLConnection httpURLConnection=(HttpURLConnection) url.openConnection();    //设置请求方式httpURLConnection.setRequestMethod("GET");//设置连接的超时时间httpURLConnection.setConnectTimeout(5000);//设置请求的头信息httpURLConnection.setRequestProperty("User-Agent","Mozilla/5.0 (Windows NT 6.2; rv:21.0) Gecko/20100101 Firefox/21.0");       //获取下载的文件大小int size=httpURLConnection.getContentLength();//根据下载文件的名称 设置本地保存的文件File file=new File("E:"&#43;path.substring(path.lastIndexOf("/")));//根据文件创建出对象accessFile=new RandomAccessFile(file, "rw");//设置大小accessFile.setLength(size);//释放资源accessFile.close();httpURLConnection.disconnect();//定义线程的数据量int threadNum=3;//往里边写数据for (int i = 1; i &lt; threadNum; i&#43;&#43;) {//计算出每个线程下载的平均量（大小）int blockSize=size/threadNum;//计算机每个线程的开始下载的位置final int startSize=(i-1)*blockSize;int temp=i*blockSize-1;if (i==threadNum) {if (temp&lt;size) {temp=size;}}//计算出每个线程下载的结束位置final int endSize=temp;//文件随机读取的对象final RandomAccessFile threadFile=new RandomAccessFile(file,"rw");//创建线程new Thread(){public void run() {try {//根据路径创建URL对象URL url=new URL(path);//打开连接HttpURLConnection httpURLConnection=(HttpURLConnection) url.openConnection();  //设置请求方式httpURLConnection.setRequestMethod("GET");//设置连接的超时时间httpURLConnection.setConnectTimeout(5000);//设置请求的头信息httpURLConnection.setRequestProperty("User-Agent","Mozilla/5.0 (Windows NT 6.2; rv:21.0) Gecko/20100101 Firefox/21.0");    System.out.println(Thread.currentThread().getName()&#43;"从--"&#43;startSize&#43;"---开始下载，到"&#43;endSize&#43;"结束");    //设置读取的range的范围    httpURLConnection.setRequestProperty("Range","bytes="&#43;startSize&#43;"-"&#43;endSize);    //获取输入流对象    InputStream is=httpURLConnection.getInputStream();    //设置文件开始写入的位置    threadFile.seek(startSize);    //缓冲区    byte  buffer[]=new byte[1024];    //读取长度    int len=0;    while((len=is.read(buffer))!=-1){    //写入    threadFile.write(buffer,0,len);    }    //释放资源    is.close();    threadFile.close();    httpURLConnection.disconnect();    } catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}};}.start();}//写文件  } catch (Exception e1) {// TODO Auto-generated catch blocke1.printStackTrace();}}}

怎么实现多线程

DownLoadJFrames2.java

package util;import java.awt.Container;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import java.io.File;import java.io.RandomAccessFile;import java.net.HttpURLConnection;import java.net.URL;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JProgressBar;import javax.swing.JTextField;public class DownLoadJFrames2 extends JFrame {// 声明组件private JLabel downlodeJlable;private JTextField downlodeJTextField;private JButton downlodeJButton;private JLabel threadNumJable;private JTextField threadNumJTextField;private JProgressBar downlodeJProgressBar;public DownLoadJFrames2() {super("下载工具");// 设置大小this.setSize(400, 300);// 设置居中显示this.setLocationRelativeTo(null);// 设置窗体关闭即退出程序this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);// 可见性this.setVisible(true);// 获取容器对象Container c = this.getContentPane();// 设置容器面板布局为nullc.setLayout(null);// 实例化组件downlodeJlable = new JLabel("下载的地址");downlodeJTextField = new JTextField("http://localhost:8080/day31/image/ff.jpg");downlodeJButton = new JButton("下载");threadNumJable=new JLabel("开启线程数");threadNumJTextField=new JTextField("3");downlodeJProgressBar=new JProgressBar();// 设置组件的位置downlodeJlable.setBounds(10, 20, 80, 30);downlodeJTextField.setBounds(95, 20, 280, 30);threadNumJable.setBounds(10,60,80,30);threadNumJTextField.setBounds(95,60,280, 30);downlodeJProgressBar.setBounds(10,100,360, 10);downlodeJButton.setBounds(120, 120, 100, 30);// 添加到面板中c.add(downlodeJButton);c.add(downlodeJTextField);c.add(downlodeJlable);c.add(threadNumJTextField);c.add(threadNumJable);c.add(downlodeJProgressBar);// 添加点击事件downlodeJButton.addActionListener(new MyActionListener());}/** * 内部类 *  * @param args */class MyActionListener implements ActionListener {// 随机文件private RandomAccessFile accessFile;@Overridepublic void actionPerformed(ActionEvent e) {downlodeJButton.setEnabled(false);// 获取下载的路径String path = downlodeJTextField.getText();String txThreadNun=threadNumJTextField.getText();try {// 根据路径创建URL对象URL url = new URL(path);// 打开连接HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();// 设置请求的方式httpURLConnection.setRequestMethod("GET");// 设置连接的超时时间httpURLConnection.setConnectTimeout(5000);// 设置请求的头信息httpURLConnection.setRequestProperty("User-Agent","Mozilla/5.0 (Windows NT 6.2; rv:21.0) Gecko/20100101 Firefox/21.0");//获取状态码int startusCode=httpURLConnection.getResponseCode();//是否响应成功的判断if (startusCode==200) {//获取下载的文件大小int size=httpURLConnection.getContentLength();//根据下载文件的名称 设置本地保存的文件File file=new File("E:"&#43;path.substring(path.lastIndexOf("/")));//根据文件创建出RandomAccessFile对象accessFile=new RandomAccessFile(file,"rw");                //设置文件大小accessFile.setLength(size);//设置进度条大小downlodeJProgressBar.setMaximum(size);downlodeJProgressBar.setValue(0);accessFile.close();httpURLConnection.disconnect();//定义线程的数据量int threadNum=Integer.parseInt(txThreadNun);//往里边写数据for (int i = 1; i &lt;=threadNum; i&#43;&#43;) {//计算出每个线程下载的平均量（大小）int blockSize=size/threadNum;//计算出每个线程的开始下载的位置int startSize=(i-1)*blockSize;//计算出每个线程下载的结束位置                    int endSize=i*blockSize-1;                    if (i==threadNum) {if (endSize&lt;size) {endSize=size;}}                    //文件随机读取的对象                    RandomAccessFile threadFile=new RandomAccessFile(file, "rw");               new DownLodeThread(path, startSize, endSize, threadFile, downlodeJProgressBar).start();                    //写文件}}} catch (Exception e1) {// TODO Auto-generated catch blocke1.printStackTrace();}}}public static void main(String[] args) {new DownLoadJFrames2();}}

怎么实现多线程

工具包DownLodeThread.java

package util;import java.io.InputStream;import java.io.RandomAccessFile;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;public class DownLodeThread extends Thread {// 下载的路径private String path;// 开始位置private int startSize;// 结束位置private int endSize;// 随机读取文件的对象private RandomAccessFile threadFile;// 实例化public DownLodeThread(String path, int startSize, int endSize,RandomAccessFile threadFile) {super();this.path = path;this.startSize = startSize;this.endSize = endSize;this.threadFile = threadFile;}@Overridepublic void run() {try {// 根据路径创建URL对象URL url = new URL(path);// 打开连接HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();// 设置请求的方式httpURLConnection.setRequestMethod("GET");// 设置连接的超时时间httpURLConnection.setConnectTimeout(5000);// 设置请求的头信息httpURLConnection.setRequestProperty("User-Agent","Mozilla/5.0 (Windows NT 6.2; rv:21.0) Gecko/20100101 Firefox/21.0");System.out.println(Thread.currentThread().getName() &#43; "从--"&#43; startSize &#43; "---开始下载，到" &#43; endSize &#43; "结束");// 设置你读取的range的范围httpURLConnection.setRequestProperty("Range", "bytes=" &#43; startSize&#43; "-" &#43; endSize);// 获取输入流对象InputStream is = httpURLConnection.getInputStream();// 设置文件开始写入的位置threadFile.seek(startSize);// 缓冲区byte buffer[] = new byte[1024];// 读取的长度int len = 0;// 读取while ((len = is.read(buffer)) != -1) {// 写入threadFile.write(buffer, 0, len);}// 释放资源is.close();threadFile.close();httpURLConnection.disconnect();} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}}

二、怎样查询AVI("video/x-msvideo")的类型

用枚举类FileType.java

package util;/** * 枚举 * @author yanmei * */public enum FileType {/** * type &lt;mime-mapping&gt; &lt;extension&gt;avi&lt;/extension&gt; * &lt;mime-type&gt;video/x-msvideo&lt;/mime-type&gt; &lt;/mime-mapping&gt; */AVI("video/x-msvideo");private String value;private FileType(String value){this.value=value;}public String getValue(){return value;}public static FileType FindByValue(String value){FileType fileType=null;FileType  types[]=FileType.values();for(FileType type:types){if (type.getValue().equals(value)) {fileType=type;break;}}return fileType;}}

测试类FileTest.java

package util;import static org.junit.Assert.*;import org.junit.Test;public class FileTest {@Testpublic void test() {FileType fileType=FileType.FindByValue("video/x-msvideo");System.out.println(fileType.name());}}

怎么实现多线程

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