package pri.lee.demo;public class HelloWord {	public static void main(String[] args) {		for (int i = 0; i < 100; i++) {			System.out.println("helloword");		}	}}

import java.io.*;import java.lang.reflect.Array;import java.lang.reflect.Method;import java.net.URL;import java.net.URLClassLoader;import java.util.ArrayList;import java.util.Enumeration;import java.util.jar.JarEntry;import java.util.jar.JarFile;import java.util.jar.Manifest;/** * @Author:li * @Date:created in 2018/1/13 11:39 */public class JarTest {    public static void main(String[] args) throws Exception {        String fileName = "C:\\Users\\marje\\Desktop\\HelloWord.jar";        File file = new File(fileName);        String mainClassName = null;        JarFile jarFile;        jarFile = new JarFile(fileName);        //获取主类        Manifest manifest = jarFile.getManifest();        if (manifest != null) {            mainClassName = manifest.getMainAttributes().getValue("Main-Class");        }        jarFile.close();        if (mainClassName == null) {            if (args.length < 2) {                System.exit(-1);            }            // 如果MANIFEST.MF未设置Main-Class,则用户输入        }        mainClassName = mainClassName.replaceAll("/", ".");        final File workDir = File.createTempFile("unjar", "",                new File(System.getProperty("user.dir")));        workDir.delete();        workDir.mkdirs();        if (!workDir.isDirectory()) {            System.err.println("Mkdirs failed to create " + workDir);            System.exit(-1);        }        unJar(file, workDir);        // 设置classPath        ArrayList
    
      classPath = new ArrayList
     
      ();        classPath.add(new File(workDir + "/").toURL());        classPath.add(file.toURL());        ClassLoader loader = new URLClassLoader(classPath.toArray(new URL[0]));        Thread.currentThread().setContextClassLoader(loader);        // 利用反射取得class和method        Class
       mainClass = Class.forName(mainClassName, true, loader);        Method main = mainClass.getMethod("main", Array                .newInstance(String.class, 1).getClass());        Object ob = mainClass.newInstance();        // 运行方法        String[] a = new String[3];        main.invoke(ob, (Object) a);        System.out.println(1);    }    public static void unJar(File jarFile, File toDir) throws IOException {        JarFile jar = new JarFile(jarFile);        try {            Enumeration entries = jar.entries();            while (entries.hasMoreElements()) {                JarEntry entry = (JarEntry) entries.nextElement();                if (!entry.isDirectory()) {                    InputStream in = jar.getInputStream(entry);                    try {                        File file = new File(toDir, entry.getName());                        if (!file.getParentFile().mkdirs()) {                            if (!file.getParentFile().isDirectory()) {                                throw new IOException(                                        "Mkdirs failed to create "                                                + file.getParentFile()                                                .toString());                            }                        }                        OutputStream out = new FileOutputStream(file);                        try {                            byte[] buffer = new byte[8192];                            int i;                            while ((i = in.read(buffer)) != -1) {                                out.write(buffer, 0, i);                            }                        } finally {                            out.close();                        }                    } finally {                        in.close();                    }                }            }        } finally {            jar.close();        }    }}