import java.io.*;
import java.util.*;
public class wren4255
{
private String msg;
public wren4255() { this("good morning"); }
public wren4255(String msg) { this.msg = msg; }
public String toString() { return ("msg:" + msg); } public static void main(String args[]){
System.out.print(new wren4255());
}
}
结果是 msg:good morning我认为,程序没有执行public String toString() 函数,怎么会输出东西呢??
import java.util.*;
public class wren4255
{
private String msg;
public wren4255() { this("good morning"); }
public wren4255(String msg) { this.msg = msg; }
public String toString() { return ("msg:" + msg); } public static void main(String args[]){
System.out.print(new wren4255());
}
}
结果是 msg:good morning我认为,程序没有执行public String toString() 函数,怎么会输出东西呢??
然后是在String的valueOf(Object o)中调用这个o.toString()方法的.
write(String.valueOf(obj));
}
---------------- public static String valueOf(Object obj) {
return (obj == null) ? "null" : obj.toString();
}
看多了自然会知道.
toString()原来是这样用的~~