java初学者题目，求详细解答

import java.io.BufferedReader;

import java.io.InputStreamReader;

import java.util.Random;

public class TestNumber {

private A a;

public void setA(A a) {

this.a = a;

}

public A getA() {

return a;

}

public boolean judge(int num) {

if (a.getV() > num) {

System.out.println("小了");

return false;

}

if (a.getV() < num) {

System.out.println("大了");

return false;

} else {

System.out.println("猜对了");

return true;

}

}

public static void main(String[] args) {

TestNumber t = new TestNumber();

A a = new A(new Random().nextInt(100));

t.setA(a);

BufferedReader str = new BufferedReader(

new InputStreamReader(System.in));

while (true) {

System.out.println("请输入要猜的数：");

try {

if (t.judge(Integer.parseInt(str.readLine()))) {

break;

}

} catch (Exception e) {

System.out.println("输入错误请重新输入：");

}

}

}

}

class A {

private int v = 100;

public A(int v) {

this.setV(v);

}

public A() {

}

public void setV(int v) {

this.v = v;

}

public int getV() {

return v;

}

}