该类主要完成查找密码，完成密码匹配。

package testthread;
import java.util.ArrayList;
import java.util.List;
public class GetPasswd extends Thread{private  List<String> passwds;private String passwd;public GetPasswd(List<String> passwds,String passwd) {this.passwds = passwds;this.passwd = passwd;}public  void getPasswd(String passwd) {char ch[] = new char[3];for (int i = 48; i < 122; i++) {for (int j = 48; j <  122; j++) {for (int k = 48; k < 122; k++) {ch[0] = (char)i;ch[1] = (char)j;ch[2] = (char)k;String str = new String(ch);passwds.add(str);if(str.equals(passwd)) {System.out.println("破解成功，密码是:" + str);return ;//return后面也可以不带参数，不带参数就是返回空，其实主要目的就是用于想中断函数执行，返回调用函数处。//为啥不能用break，因为break只终止最内层的循环}}}}}public void run() {getPasswd(passwd);}
}

该类主要完成log打印，完成守护线程。

/**  
package testthread;
import java.util.List;
public class TestDaemon extends Thread{private List<String> slist;public TestDaemon(List<String> s) {this.slist = s;this.setDaemon(true);}public void run() {while(slist.isEmpty()) {try {Thread.sleep(1000);} catch (InterruptedException e) {// TODO Auto-generated catch blocke.printStackTrace();}}while(true) {String s = slist.remove(0);System.out.println("穷举法本次生成的密码是：" +s);}	}
}

以下是测试类

package testthread;
import java.util.ArrayList;
import java.util.List;public class TestGetPasswd {public static void main(String[] args) {String a = generateRandomString(3);System.out.println("产生的原始密码为:"+a);List<String> s = new ArrayList<>();GetPasswd gp = new GetPasswd(s, a);gp.start();TestDaemon td = new TestDaemon(s);td.start();}public static String generateRandomString(int len) {StringBuffer sb = new StringBuffer();for(int i = 0; i < len; i++) {while(true) {char ch = (char)(Math.random()*'z');if(Character.isDigit(ch)||Character.isLetter(ch)) {sb.append(ch);break;}}}return sb.toString();}
}