Java中的这个 - 线程“main”中的异常java.lang.StackOverflowError
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This in Java - Exception in thread "main" java.lang.StackOverflowError
提问by Erran Morad
Why am I getting a stackoverflow error ?
为什么会出现计算器溢出错误？
My class -
我的课 -
public class Tester {
int id;
Tester(int id){
this.id = id;
}
public String toString(){
String rep = "Hex: " + this + ", Id: " + this.id;
return rep;
}
}
The main method -
主要方法——
class Driver{
public static void main(String [] args){
Tester t = new Tester(123);
System.out.println(t);
}
}
Error -
错误 -
Exception in thread "main" java.lang.StackOverflowError
at java.lang.String.length(Unknown Source)
at java.lang.AbstractStringBuilder.append(Unknown Source)
at java.lang.StringBuilder.append(Unknown Source)
at java.lang.StringBuilder.<init>(Unknown Source)
at com.examscam.model.Tester.toString(Tester.java:13)
at java.lang.String.valueOf(Unknown Source)
at java.lang.StringBuilder.append(Unknown Source)
---------REPEAT !!!
采纳答案by Parul S
You wrote:
你写了：
String rep = "Hex: " + this + ", Id: " + this.id;
In java simply writing thismeans that you are indirectly invoking this.toString().
在 Java 中，简单的写法this意味着您间接调用this.toString().
I believe you are trying to override the toString()method of Objectand inside your version of toString()you want to print the id you have passed along with the hashcodeof the object.
我相信你正试图重写toString()的方法Object和你的版本里面toString()你想打印已与一起传入的idhashcode的对象。
So to get the output replace
所以要得到输出替换
String rep = "Hex: " + this + ", Id: " + this.id;
with
和
String rep = "Hex: "+ this.getClass().getName().hashCode() +", Id: " + id;
and you will get the output as:
你会得到如下输出：
Hex: 1800024669, Id: 123
回答by Rahul
you are using thiskeyword.
您正在使用this关键字。
String rep = "Hex: " + this + ", Id: " + this.id;
This represent the current object. Your current object is being called again and again recursivley so you are getting
这代表当前对象。你当前的对象被一次又一次地递归调用，所以你得到
java.lang.StackOverflowError
java.lang.StackOverflowError
回答by MrP
You are appending "this". This calls the toString() method, which again calls toString(), ... It's an infinite recursion loop, which does not have an end.
您正在附加“这个”。这将调用 toString() 方法，该方法再次调用 toString()，...这是一个无限递归循环，没有结束。
回答by geoand
Because you are referencing thisin toString()
因为您this在 toString()中引用
That means that this.toString()is being called, therefor infinite recursion is occurring
这意味着this.toString()正在被调用，因此正在发生无限递归
回答by JB Nizet
Because
因为
"Hex: " + this
is equivalent to
相当于
"Hex: " + this.toString()
and you're doing that from the toString(), so toString()calls itself, which calls itself, which calls itself...
你是从toString(), 所以toString()调用它自己，它调用它自己，它调用它自己......
回答by Elliott Frisch
Your toString method is the culprit,
你的 toString 方法是罪魁祸首，
String rep = "Hex: " + super.toString() /* Not this */
+ ", Id: " + this.id;
回答by niiraj874u
thi line
这条线
String rep = "Hex: " + this + ", Id: " + this.id;
would become
会成为
String rep = "Hex: " + this.toString() + ", Id: " + this.id;
at run-time and will again call your class's toString..wi again..
在运行时，将再次调用您班级的 toString..wi..
回答by Vineet Singla
In the line String rep = "Hex: " + this + ", Id: " + this.id;
在行中 String rep = "Hex: " + this + ", Id: " + this.id;
this
is equivalent to
相当于
this.toString()
and calling it from the toString(), will again call toString and again...
并从 toString() 调用它，将再次调用 toString 并再次...
回答by Blue Ocean
I think you are overriding toString method and in your overrided method body your calling your method again! you are calling toString by writing this+"" in toString method
我认为您正在覆盖 toString 方法，并且在您覆盖的方法主体中再次调用您的方法！您通过在 toString 方法中写入 this+"" 来调用 toString
回答by Naveen
String rep = "Hex: " + this + ", Id: " + this.id;
equal to String rep = "Hex: " + this.toString() + ", Id: " + this.id;internally
等于 String rep = "Hex: " + this.toString() + ", Id: " + this.id;内部
this will leads to recursive method call that will result in
这将导致递归方法调用，这将导致
java.lang.StackOverflowError
