新手求大神解，这两者的不同，和优劣。虚心求教！！

[Yanpevg]

import java.util.*;
public class game{
public static void main(String[] arges){
System.out.println("-----猜拳游戏-----");
System.out.println("1石头，2剪刀，3布");
System.out.println("请输入");
Scanner in=new Scanner(System.in);
Random number=new Random();
int number3=number.nextInt(3)+1;
int number1=in.nextInt();
if(number1==1&&number3==3){
System.out.println("你出的石头,电脑是布,-_-你输了");
}else if(number1==1&&number3==2){
System.out.println("你出的石头,电脑是剪刀,^_^你赢了");
}else if(number1==1&&number3==1){
System.out.println("你出的石头,电脑是石头,平局");
}else if(number1==2&&number3==2){
System.out.println("你出的剪刀,电脑是剪刀,平局");
}else if(number1==2&&number3==3){
System.out.println("你出的剪刀,电脑是布,^_^你赢了");
}else if(number1==2&&number3==1){
System.out.println("你出的剪刀,电脑是石头,-_-你输了");
}else if(number1==3&&number3==3){
System.out.println("你出的布,电脑是布,平局");
}else if(number1==3&&number3==2){
System.out.println("你出的布,电脑是剪刀,-_-你输了");
}else if(number1==3&&number3==1){
System.out.println("你出的是布,电脑是石头,^_^你赢了");
}

}
}

[为谁烽火连城]

前者代码节俭，会节省很多运行成本的！

[zhuangqingch]

1、从运行效率上看，前者与后者相比判断次数较少一些（其实也只少了一点点，else if中用了几个或||），所以会快一点点。 2、从代码简洁及可读性上看，前者相比后者会简洁一些，可读性也要比较后者要好且易理解，后者判断太多，虽然穷举出所有可能的判断，但有时难免会有一些遗漏。 根据楼主想要实现的效果，对楼主的代码做了点调整，楼主可以参考下： 第一种实现（优化输出描述）：

import java.util.Scanner;
/**
 * @author zhuangqing
 */
public class Test {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String[] msg = {"剪刀","石头", "布"};
        System.out.println("-----猜拳游戏-----");
        System.out.println("请出拳（1剪刀，2石头，3布）");
        int person = in.nextInt();
        int computer = (int)(Math.random()*3) + 1;
        String result = "电脑出的是：" + msg[computer-1] + "，你出的是：" + msg[person - 1];
        if (person == computer) {
            System.out.println("平局，" + result);
        } else if (person == 1&&computer==2||person==2&&computer==3||person==3&&computer==1) {
            System.out.println("你输了，" + result);
        } else {
            System.out.println("你赢了，" + result);
        }
    }
}

第二种实现（优化判断次数）：

import java.util.Scanner;

/**
 * @author zhuangqing
 */
public class Test2 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String[] msg = {"剪刀","石头", "布"};
        System.out.println("-----猜拳游戏-----");
        System.out.println("请出拳（1剪刀，2石头，3布）");
        int person = in.nextInt();
        int computer = (int)(Math.random()*3) + 1;
        String result = "电脑出的是：" + msg[computer-1] + "，你出的是：" + msg[person - 1];
        int naturalEnemy = (person+1)%3; //天敌
        if (naturalEnemy == computer) {
            System.out.println("你输了，" + result);
        } else if (person == computer) {
            System.out.println("平局，" + result);
        } else {
            System.out.println("你赢了，" + result);
        }
    }
}

第三种实现：（优化面向对象设计）

import java.util.Scanner;
/**
 * @author zhuangqing
 */
public class Test3 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        GuessingResult[] results = {GuessingResult.SCISSOR, GuessingResult.ROCK, GuessingResult.PAPER};
        System.out.println("-----猜拳游戏-----");
        System.out.println("请出拳（1剪刀，2石头，3布）");
        int person = in.nextInt();
        int computer = (int)(Math.random()*3) + 1;
        GuessingResult personResult = results[person - 1];
        GuessingResult computerResult = results[computer-1];
        String result = "电脑出的是：" + computerResult.getDesc() + "，你出的是：" + personResult.getDesc();

        if (personResult.naturalEnemy() == computerResult) {
            System.out.println("你输了，" + result);
        } else if (personResult.defeatedByMe() == computerResult) {
            System.out.println("你赢了，" + result);
        } else {
            System.out.println("平局，" + result);
        }
    }
}

/**
 * 猜拳结果枚举类
 */
enum GuessingResult {
    SCISSOR("剪刀"){
        public GuessingResult  naturalEnemy() {
            return ROCK;
        }
        public GuessingResult defeatedByMe() {
            return PAPER;
        }
    },
    ROCK("石头"){
        public GuessingResult  naturalEnemy() {
            return PAPER;
        }
        public GuessingResult defeatedByMe() {
            return SCISSOR;
        }
    },
    PAPER("布"){
        public GuessingResult  naturalEnemy() {
            return SCISSOR;
        }
        public GuessingResult defeatedByMe() {
            return ROCK;
        }
    },
    ;
    private String desc;
    GuessingResult(String desc) {
        this.desc = desc;
    }

    public String getDesc() {
        return desc;
    }

    /**
     * 天敌
     * @return
     */
    public abstract GuessingResult  naturalEnemy();

    /**
     * 能击败的对象
     * @return
     */
    public abstract GuessingResult defeatedByMe();
}

就这些吧，希望这些代码能对楼主有所帮助，有不明白的，欢迎追问！