java - 调用setMod()方法时出现异常

Question

这是我的代码:

package dsboy08.BattleX;

import java.util.Scanner;
import java.util.Random;
/**
* Created by dsboy08 on 11/23/14.
*/
public class Start {
public String enemyName;
public int playerHP;
public int enemyHP;
public int playerMinDamageHit;
public int playerMaxDamageHit;
public int enemyMinDamageHit;
public int enemyMaxDamageHit;
public int playerHealMin;
public int playerHealMax;
public void setMod(String LocalModName, String LocalEnemyName, int LocalPlayerHP, int LocalEnemyHP, int LocalPlayerMinDamageHit, int LocalPlayerMaxDamageHit, int LocalEnemyMinDamageHit, int LocalEnemyMaxDamageHit, int LocalPlayerHealMin, int LocalPlayerHealMax){
    playerHP = LocalPlayerHP;
    enemyName = LocalEnemyName;
    enemyHP = LocalEnemyHP;
    playerMinDamageHit = LocalPlayerMinDamageHit;
    playerMaxDamageHit = LocalPlayerMaxDamageHit;
    enemyMinDamageHit = LocalEnemyMinDamageHit;
    enemyMaxDamageHit = LocalEnemyMaxDamageHit;
    playerHealMin = LocalPlayerHealMin;
    playerHealMax = LocalPlayerHealMax;
    print("Welcome to BattleX! Press 1 to start and 2 to exit.");
    print("Mod: "+LocalModName+" loaded.");
    Scanner menuItem = new Scanner(System.in);
    String menuItem2 = menuItem.nextLine();
    if(menuItem2.equals("1")) {
        startGame();
    }else {
        if (menuItem2.equals("2")) {
            System.exit(0);
        } else {
            System.exit(0);
        }
    }
}

public void print(String text){
    System.out.println(text);
}

public void startGame(){
    print("Current "+enemyName+" HP: "+playerHP);
    print("Your current HP: "+enemyHP);
    print("1: Attack");
    print("2: Heal");
    Scanner battleOption = new Scanner(System.in);
    String battleOption2 = battleOption.nextLine();
    if(battleOption2.equals("1")) {
        attack();
    }else {
        if (battleOption2.equals("2")) {
            heal();
        }else{
            startGame();
        }
    }
}

public void attack(){
    Random humanAttack = new Random();
    int attackDamage = humanAttack.nextInt((playerMinDamageHit - playerMaxDamageHit) + 1) + playerMinDamageHit;
    print("Attacking for " + attackDamage + " damage.");
    enemyHP = enemyHP - attackDamage;
    int bearAttackDamage = humanAttack.nextInt((enemyMinDamageHit - enemyMaxDamageHit) + 1) + enemyMinDamageHit;
    print("The "+enemyName+" attacked for "+bearAttackDamage+" damage.");
    playerHP = playerHP - bearAttackDamage;
    if(playerHP <= 0){
        print("You failed! The "+enemyName+" killed you ;)");
        System.exit(0);
    }
    if(enemyHP <= 0){
        print("You defeated the "+enemyName+"! Good job!");
        System.exit(0);
    }
    startGame();
}

public void heal(){
    Random healAmount = new Random();
    int randomHealAmount = healAmount.nextInt((playerHealMin - playerHealMin) + 1) + playerHealMin;
    int bearAttackDamage = healAmount.nextInt((enemyMinDamageHit - enemyMaxDamageHit) + 1) + enemyMinDamageHit;
    playerHP = playerHP + randomHealAmount;
    if(playerHP + randomHealAmount >= 100){
        playerHP = 100;
    }
    playerHP = playerHP - bearAttackDamage;
    print("You have healed "+randomHealAmount+" health, but you have also lost "+bearAttackDamage+" health.");
    if(playerHP <= 0){
        print("You failed! The "+enemyName+" killed you ;)");
        System.exit(0);
    }
    if(enemyHP <= 0){
        print("You defeated the "+enemyName+"! Good job!");
        System.exit(0);
    }
    startGame();
}
}

这是我的“主要”代码:

 public static void main(String[] args){
    new dsboy08.BattleX.Start().setMod("ExampleMod", "Death", 100, 50, 5, 10, 5, 15, 3, 10);
}

我得到一个异常(似乎是静态上下文，但我似乎无法修复它)。

这是我的异常调用:

Exception in thread "main" java.lang.IllegalArgumentException: bound must be positive
at java.util.Random.nextInt(Random.java:388)
at dsboy08.BattleX.Start.attack(Start.java:67)
at dsboy08.BattleX.Start.startGame(Start.java:55)
at dsboy08.BattleX.Start.setMod(Start.java:33)
at dsboy08.BattleX.ModStart.main(ModStart.java:8)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:483)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:134)

我试图通过使方法不是静态的来修复它，但它并没有真正起作用。

Answer 1

这里会发生什么:

humanAttack.nextInt((enemyMinDamageHit - enemyMaxDamageHit) + 1)

如果.nextInt(...)方法的参数为负数？你会得到一个异常(exception)，就是这样。由于 Max > Min，所以这是可能的。您最好确保参数实际上是正数。

我自己，我会通过改变来交换它们

humanAttack.nextInt((enemyMinDamageHit - enemyMaxDamageHit) + 1)

到

humanAttack.nextInt((enemyMaxDamageHit - enemyMinDamageHit) + 1)

<小时/><小时/>

最重要的是，您需要批判性地阅读所有异常消息，因为它们传递给您的信息不是胡言乱语，而是经常(在您的情况下准确地)告诉您哪里出了问题。

您的异常消息告诉您:

Exception in thread "main" java.lang.IllegalArgumentException: bound must be positive

所以你知道用作方法或构造函数参数的某些数字是负数，但实际上应该是正数。

at java.util.Random.nextInt(Random.java:388)

好的，它涉及到 Random 对象的 nextInt(...) 调用。

at dsboy08.BattleX.Start.attack(Start.java:67)

问题出在 Start 类的第 67 行，在攻击方法中。