Java 创建单个对象时如何执行多个构造函数
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How to execute multiple constructor, when creating single object
提问by CodeCrypt
I want to execute multiple constructor, while creating a single object. For example, I have a class definition like this-
我想在创建单个对象的同时执行多个构造函数。例如，我有一个这样的类定义-
public class Prg
{
public Prg()
{
System.out.println("In default constructor");
}
public Prg(int a)
{
System.out.println("In single parameter constructor");
}
public Prg(int b, int c)
{
System.out.println("In multiple parameter constructor");
}
}
And I am trying to achieve it by the following code -
我正在尝试通过以下代码来实现它 -
public class Prg
{
public Prg()
{
System.out.println("In default constructor");
}
public Prg(int a)
{
Prg();
System.out.println("In single parameter constructor");
}
public Prg(int b, int c)
{
Prg(b);
System.out.println("In multiple parameter constructor");
}
public static void main(String s[])
{
Prg obj = new Prg(10, 20);
}
}
But in this case it is generating errors like -
但在这种情况下，它会产生如下错误 -
Prg.java:11: error: cannot find symbol
Prg();
^
symbol: method Prg()
location: class Prg
Prg.java:16: error: cannot find symbol
Prg(b);
^
symbol: method Prg(int)
location: class Prg
2 errors
Thanks
谢谢
采纳答案by Manuel Manhart
Use this()instead of Prg()in your constructors
在构造函数中使用this()而不是Prg()
回答by ahmedalkaff
When calling other constructors Use this()instead of Prg()
调用其他构造函数时使用this()代替Prg()
回答by Jayamohan
You should use thisstatement.
你应该使用this语句。
e.g.
例如
public Prg(int b, int c)
{
this(b);
System.out.println("In multiple parameter constructor");
}
回答by Prasad Kharkar
Use thisinstead of Prg
使用this代替Prg
public Prg()
{
System.out.println("In default constructor");
}
public Prg(int a)
{
this();
System.out.println("In single parameter constructor");
}
public Prg(int b, int c)
{
this(b);
System.out.println("In multiple parameter constructor");
}
回答by SpringLearner
use thiskeyword.Full running code is as follows
使用this关键字。完整运行代码如下
public class Prg
{
public Prg()
{
System.out.println("In default constructor");
}
public Prg(int a)
{
this();
System.out.println("In single parameter constructor");
}
public Prg(int b, int c)
{
//Prg obj = new Prg(10, 20);
this(b); System.out.println("In multiple parameter constructor");
}
public static void main(String s[])
{
Prg obj = new Prg(10, 20);
}
}
