Java中toString()的使用

Java中提供了toString()方法，但如何使用？
先看个例子：

//代码1public class hw {    public static void main(String[] args) {        hw w = new hw();        System.out.println(w.toString());    }}

打印出来的是类名加地址形式的字符串。

那么如何对toString()方法进行使用？
再看一个例子：

//代码2public class Fan {    final int slow = 1;    final int medium = 2;    final int fast = 3;    public int speed = 1;    public boolean on = false;    public double radiu = 5;    String color = "blue";    public int getSpeed() {        return speed;    }    public void setSpeed(int speed) {        this.speed = speed;    }    public boolean isOn() {        return on;    }    public void setOn(boolean on) {        this.on = on;    }    public double getRadiu() {        return radiu;    }    public void setRadiu(double radiu) {        this.radiu = radiu;    }    public String getColor() {        return color;    }    public void setColor(String color) {        this.color = color;    }    public String toString() {        if (on == true) {            return "fan is on: " + on +" "+ "[color: " + color + "]" + "[radius: " + radiu + "] " + "[speed: " + speed                    + "] ";        } else {            return "fan is off:  " + "[color: " + color + "]" + " " + "[radius: " + radiu + "] ";        }    }}public class test {    public static void main(String[] args) {        Fan f1 = new Fan();        f1.setSpeed(3);        f1.setOn(true);        f1.setRadiu(10);        f1.setColor("yellow");        Fan f2 = new Fan();        f2.setOn(false);        f2.setSpeed(2);        f2.setRadiu(5);        f2.setColor("blue");        System.out.println(f1.toString());        System.out.println(f2.toString());        }    }

从中看出调用toString()方法要对其进行重写将原来的toString()方法覆盖。

拓展阅读：
各种面向对象程序语言的toString方法实现
http://blog.iderzheng.com/how-to-implement-tostring-in-different-languages/

JAVA中toString方法的作用
http://www.cnblogs.com/zhangjs8385/archive/2011/10/10/2205281.html