Question

当我运行javac Hero.java然后java Hero程序会吐出大量看起来像这样的行：

Hero@322ba3e4
Hero@4f14e777
Hero@65685e30
Hero@26ffd553
Hero@660e5025
Hero@35afe17b

这是什么？ Hero@322ba3e4

然后显示，

Exception in thread "main" java.lang.StackOverflowError
    at sun.nio.cs.UTF_8.updatePositions(UTF_8.java:77)
    at sun.nio.cs.UTF_8$Encoder.encodeArrayLoop(UTF_8.java:564)
    at sun.nio.cs.UTF_8$Encoder.encodeLoop(UTF_8.java:619)
    at java.nio.charset.CharsetEncoder.encode(CharsetEncoder.java:561)
    at sun.nio.cs.StreamEncoder.implWrite(StreamEncoder.java:271)
    at sun.nio.cs.StreamEncoder.write(StreamEncoder.java:125)
    at java.io.OutputStreamWriter.write(OutputStreamWriter.java:207)
    at java.io.BufferedWriter.flushBuffer(BufferedWriter.java:129)
    at java.io.PrintStream.write(PrintStream.java:526)
    at java.io.PrintStream.print(PrintStream.java:669)
    at java.io.PrintStream.println(PrintStream.java:823)
    at Hero.DrowRanger(Hero.java:78)
    at Hero.DrowRanger(Hero.java:79)

这一行重复了100次：

at Hero.DrowRanger(Hero.java:79)

这是该行的方法，

            private static Object DrowRanger() {
            Hero DrowRanger = new Hero(
                  0,
                  "Agility",
                  "Ranged",
                  "Frost Arrows",
                  "Gust",
                  "Precision Aura",
                  "Marksmanship",
                  17,
                  1.9,
                  26,
                  1.9,
                  15,
                  1.4,
                  473,
                  195,
                  44,
                  55,
                  625,
                  0.64,
                  300);

       System.out.println(DrowRanger);
 return DrowRanger();                // Line 79 Is Here      
}

这是完整的课程

public class Hero implements NPC {

        private int level;
        private String primaryAttribute;
        private String attackType;
        private String ability1;
        private String ability2;
        private String ability3;
        private String ability4;
        private double strength;
        private double strengthMultiplier;
        private double agility;
        private double agilityMultiplier;
        private double intelligence;
        private double intelligenceMultiplier;
        private int health;
        private int mana;
        private int damageMin;
        private int damageMax;
        private int range;
        private double armor;
        private int movement;

        //default constructor
        public Hero(
                int level,
                String primaryAttribute,
                String attackType,
                String ability1,
                String ability2,
                String ability3,
                String ability4,
                double strength,
                double strengthMultiplier,
                double agility,
                double agilityMultiplier,
                double intelligence,
                double intelligenceMultiplier,
                int health,
                int mana,
                int damageMin,
                int damageMax,
                int range,
                double armor,
                int movement
                    ) {

        } // End Constructor

        public static void main (String[] args) {
            DrowRanger();

            }

        private static Object DrowRanger() {
        Hero DrowRanger = new Hero(
              0,
              "Agility",
              "Ranged",
              "Frost Arrows",
              "Gust",
              "Precision Aura",
              "Marksmanship",
              17,
              1.9,
              26,
              1.9,
              15,
              1.4,
              473,
              195,
              44,
              55,
              625,
              0.64,
              300);

        System.out.println(DrowRanger);
        return DrowRanger();
}


        // getters and setters - required to implement ALL from interface
        public int getLevel() {
            return this.level;
        }

        public String getPrimaryAttribute() {
            return this.primaryAttribute;
        }

        public String getAttackType() {
            return this.attackType;
        }

        public String getAbility1() {
            return this.ability1;
        }

        public String getAbility2() {
            return this.ability2;
        }

        public String getAbility3() {
            return this.ability3;
        }

        public String getAbility4() {
            return this.ability4;
        }

        public double getStrength() {
            return this.strength;
        }

        public double getStrengthMultiplier() {
            return this.strengthMultiplier;
        }

        public double getAgility() {
            return this.agility;
        }

        public double getAgilityMultiplier() {
            return this.agilityMultiplier;
        }

        public double getIntelligence() {
            return this.intelligence;
        }

        public double getIntelligenceMultiplier() {
            return this.intelligenceMultiplier;
        }

        public int getHealth() {
            return this.health;
        }

        public int getMana() {
            return this.mana;
        }

        public int getDamageMin() {
            return this.damageMin;
        }

        public int getDamageMax() {
            return this.damageMax;
        }

        public int getRange() {
            return this.range;
        }

        public double getArmor() {
            return this.armor;
        }

        public int getMovement() {
            return this.movement;
        }

    // This is where the setters are.

        public void setLevel(int level) {
            this.level = level;
        }

        public void setPrimaryAttribute(String primaryAttribute) {
            this.primaryAttribute = primaryAttribute;
        }

        public void setAttackType(String attackType) {
            this.attackType = attackType;
        }

        public void setAbility1(String ability1) {
            this.ability1 = ability1;
        }

        public void setAbility2(String ability2) {
            this.ability2 = ability2;
        }

        public void setAbility3String(String ability3) {
            this.ability3 = ability3;
        }

        public void setAbility4(String ability4) {
            this.ability4 = ability4;
        }

        public void setStrength(double strength) {
            this.strength = strength;
        }

        public void setStrengthMultiplier(double strengthMultiplier) {
            this.strengthMultiplier = strengthMultiplier;
        }

        public void setAgility(double agility) {
            this.agility = agility;
        }

        public void setAgilityMultiplier(double agilityMultiplier) {
            this.agilityMultiplier = agilityMultiplier;
        }

        public void setIntelligence(double intelligence) {
            this.intelligence = intelligence;
        }

        public void setIntelligenceMultiplier(double intelligenceMultiplier) {
            this.intelligenceMultiplier = intelligenceMultiplier;
        }

        public void setHealth(int health) {
            this.health = health;
        }

        public void setMana(int mana) {
            this.mana = mana;
        }

        public void setDamageMin(int damageMin) {
            this.damageMin = damageMin;
        }

        public void setDamageMax(int damageMax) {
            this.damageMax = damageMax;
        }

        public void setRange(int range) {
            this.range = range;
        }

        public void setArmor(double armor) {
            this.armor = armor;
        }

        public void setMovement(int movement) {
            this.movement = movement;
        }

    } // End Character Class
`

Answer 1

您的DrowRanger方法无限地调用自己。这几乎总是StackOverflowException的原因。

这一行：

return DrowRanger();

调用DrowRanger方法，但由于您在DrowRanger方法内，它只是无限地调用自己。我想你的意思是返回本地对象：

return DrowRanger;

通常，给方法和对象赋予相同的名称是个坏主意。此外，java惯例始终是start方法，变量/字段名称是小写字母。

您看到的输出是java打印未覆盖toString()方法的对象的方式。有关toString()方法的工作原理的说明，请参见this post。

Answer 2

到第一个：println打印对象的toString方法的输出。因为它只是Object类继承的普通方法，所以它只返回类的名称和对象的哈希值。对于你的错误：看起来某处有一个无限循环（已找到）。

Java程序在崩溃前无限打印

2 个答案: