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1．toString()方法e69da5e887aa3231313335323631343130323136353331333262353935

Object类具有一个toString()方法，你创建的每个类都会继承该方法。它返回对象的一个String表示，并且对于调试非常有帮助。然而对于默认的toString()方法往往不能满足需求，需要覆盖这个方法。

toString()方法将对象转换为字符串。看以下代码：

package sample;

class Villain {

private String name;

protected void set(String nm) {

name = nm;

}

public Villain(String name) {

this.name = name;

}

public String toString() {

return "I'm a Villain and my name is " + name;

}

}

public class Orc extends Villain {

private int orcNumber;

public Orc(String name, int orcNumber) {

super(name);

this.orcNumber = orcNumber;

}

public void change(String name, int orcNumber) {

set(name);

this.orcNumber = orcNumber;

}

public String toString() {

return "Orc" + orcNumber + ":" + super.toString();

}

public static void main(String[] args) {

Orc orc = new Orc("Limburger", 12);

System.out.println(orc);

orc.change("Bob", 19);

System.out.println(orc);

}

}

结果：

sample.Orc@11b86e7

sample.Orc@11b86e7

如果去掉注释，即加入2个toString()方法后，得到

结果：

Orc12:I'm a Villain and my name is Limburger

Orc19:I'm a Villain and my name is Bob

2．在容器类中使用toString()

编写一个工具类，用于在控制台输出Iterator。

import java.util.Iterator;

public class Printer {

static void printAll(Iterator e){

while(e.hasNext()){

System.out.println(e.next());

}

}

}

在Hamster类中重写父类的toString()方法。

public class Hamster {

private int hamsterNumber;

public Hamster(int hamsterNumber){

this.hamsterNumber=hamsterNumber;

}

public String toString(){

return "This is Hamster #"+hamsterNumber;

}

}

在HamsterMaze类中使用容器类加载Hamster类对象并输出结果。

import java.util.ArrayList;

import java.util.List;

public class HamsterMaze {

@SuppressWarnings("unchecked")

public static void main(String[] args){

List list=new ArrayList();

for(int i=0;i<3;i++)

list.add(new Hamster(i));

Printer.printAll(list.iterator());

}

}

结果：

This is Hamster #0

This is Hamster #1

This is Hamster #2

3．一个实现toString()的通用的Bean

在作一个项目时发现,许多bean需要实现toString()方法,就实现一个通用的bean,然后通过其他继承即可。

import java.lang.reflect.Field;

public class BaseBean {

public String toString() {

StringBuffer sb = new StringBuffer();

try {

Class t = this.getClass();

Field[] fields = t.getDeclaredFields();

for (int i = 0; i < fields.length; i++) {

Field field = fields[i];

field.setAccessible(true);

sb.append("{");

sb.append(field.getName());

sb.append(":");

if (field.getType() == Integer.class) {

sb.append(field.getInt(this));

} else if (field.getType() == Long.class) {

sb.append(field.getLong(this));

} else if (field.getType() == Boolean.class) {

sb.append(field.getBoolean(this));

} else if (field.getType() == char.class) {

sb.append(field.getChar(this));

} else if (field.getType() == Double.class) {

sb.append(field.getDouble(this));

} else if (field.getType() == Float.class) {

sb.append(field.getFloat(this));

} else

sb.append(field.get(this));

sb.append("}");

}

} catch (Exception e) {

e.printStackTrace();

}

return sb.toString();

}

}

测试类

public class TestBean extends BaseBean {

private int id;

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public static void main(String[] args) {

TestBean testBean = new TestBean();

testBean.setId(9);

System.out.println(testBean.toString());

}

}

结果

{id:9}

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/liumx2007/archive/2008/08/23/2817567.aspx

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