操作Beans的属性

/**
*@ author StormMaybin
*@ date 2016-10-06
*/

生命不息，奋斗不止！

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使用内省API操作Bean的属性

API

package com.stormma.introspector;

import java.util.Date;

public class Person
{
    private String name;
    private int age;
    private Date birthday;
    public String getName()
    {
        return name;
    }
    public void setName(String name)
    {
        this.name = name;
    }
    public int getAge()
    {
        return age;
    }
    public void setAge(int age)
    {
        this.age = age;
    }
    public Date getBirthday()
    {
        return birthday;
    }
    public void setBirthday(Date birthday)
    {
        this.birthday = birthday;
    }
}

操作bean的属性

package com.stormma.introspector;

import java.beans.BeanInfo;
import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class Demo1
{
    public static void main(String[] args) throws IntrospectionException, IllegalAccessException, IllegalArgumentException, InvocationTargetException
    {
//      getBean();
        setGetBean();
    }
    private static void setGetBean() throws IntrospectionException,
            IllegalAccessException, InvocationTargetException
    {
        Person p = new Person ();
        PropertyDescriptor pd = new PropertyDescriptor ("age", Person.class);
        //得到bean的属性的set方法
        Method method = pd.getWriteMethod();
        method.invoke(p, 20);

        //得到bean的属性的get方法
        Method getMethod = pd.getReadMethod();
        System.out.println(getMethod.invoke(p, null));
        System.out.println(p.getAge());
    }
    /**
     * 得到bean的属性
     * @throws IntrospectionException
     */
    private static void getBean() throws IntrospectionException
    {
        //剔除Object的bean的属性
        BeanInfo info = Introspector.getBeanInfo(Person.class, Object.class);
        PropertyDescriptor [] pds = info.getPropertyDescriptors();
        for (PropertyDescriptor pd : pds)
        {
            System.out.println(pd.getName());
        }
    }
}

使用apache 的BeanUtils操作bean的属性

ps： 需要jar包commons-beanutils-x.x.x.jar同时commons-beanutils-x.x.x.jar。需要commons-logging.jar日志记录器来支持。所以用beanUtils的时候需要导入两个jar包。

package com.stormma.beanutils;

import java.lang.reflect.InvocationTargetException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.apache.commons.beanutils.BeanUtils;
import org.apache.commons.beanutils.ConversionException;
import org.apache.commons.beanutils.ConvertUtils;
import org.apache.commons.beanutils.Converter;
import org.apache.commons.beanutils.locale.converters.DateLocaleConverter;


public class Main
{
    public static void main(String[] args)
    {
        try
        {
            // test1();
            // test2();
            // test3();
//          test4();
            test5();
        } catch (IllegalAccessException | InvocationTargetException e)
        {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    /**
     * 用BeanUtils操作bean的属性
     * 
     * @throws InvocationTargetException
     * @throws IllegalAccessException
     */
    private static void test1() throws IllegalAccessException,
            InvocationTargetException
    {
        Person p = new Person();
        BeanUtils.setProperty(p, "name", "StormMa");
        System.out.println(p.getName());
    }

    /**
     * 找到数据封装对象
     * 
     * @throws IllegalAccessException
     * @throws InvocationTargetException
     */
    private static void test2() throws IllegalAccessException,
            InvocationTargetException
    {
        Person p = new Person();

        String name = "StormMa";
        String age = "20";

        BeanUtils.setProperty(p, "name", name);
        // 转换器(String --> int)
        // 但是只支持八种基本数据类型的转换
        // 如果要转换其他的类型，可以自定义转换器
        BeanUtils.setProperty(p, "age", age);

        System.out.println(p.getName() + "   " + p.getAge());
    }

    /**
     * 有问题代码String cannot convert to Date
     * 
     * @throws IllegalAccessException
     * @throws InvocationTargetException
     */
    private static void test3() throws IllegalAccessException,
            InvocationTargetException
    {
        Person p = new Person();

        String name = "StormMa";
        String age = "20";
        String birthday = "1996-02-16";

        BeanUtils.setProperty(p, "name", name);
        // 转换器(String --> int)
        // 但是只支持八种基本数据类型的转换
        // 如果要转换其他的类型，可以自定义转换器
        BeanUtils.setProperty(p, "age", age);
        // 错误，只支持八种基本数据类型转换
        BeanUtils.setProperty(p, "birthday", birthday);

        System.out.println(p.getName() + "   " + p.getAge() + "   "
                + p.getBirthday());
    }

    /**
     * 自定义转换器
     * 
     * @throws IllegalAccessException
     * @throws InvocationTargetException
     */
    private static void test4() throws IllegalAccessException,
            InvocationTargetException
    {
        Person p = new Person();

        String name = "StormMa";
        String age = "20";
        String birthday = "1996-02-16";

        // 注册日期转换器
        ConvertUtils.register(new Converter()
        {
            @Override
            public <T> T convert(Class<T> type, Object value)
            {
                // TODO Auto-generated method stub
                // 先检查数据
                if (value == null)
                {
                    return null;
                } else if (!(value instanceof String))
                {
                    throw new ConversionException("只支持String转换");
                } else if (((String) value).trim().equals(""))
                {
                    return null;
                }

                SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
                try
                {
                    return (T) df.parse((String) value);
                } catch (ParseException e)
                {
                    // TODO Auto-generated catch block
                    // 异常链不能断
                    throw new RuntimeException(e);
                }
            }

        }, Date.class);

        BeanUtils.setProperty(p, "name", name);
        // 转换器(String --> int)
        // 但是只支持八种基本数据类型的转换
        // 如果要转换其他的类型，可以自定义转换器
        BeanUtils.setProperty(p, "age", age);
        // 错误，只支持八种基本数据类型转换
        BeanUtils.setProperty(p, "birthday", birthday);

        System.out.println(p.getName() + "   " + p.getAge() + "   "
                + p.getBirthday().toLocaleString());
    }
    /**
     * apache内置Date转换器，有小bug
     * @throws IllegalAccessException
     * @throws InvocationTargetException
     */
    private static void test5() throws IllegalAccessException,
            InvocationTargetException
    {
        Person p = new Person();

        String name = "StormMa";
        String age = "20";
        String birthday = "1996-02-16";

        //提供转换器
        ConvertUtils.register(new DateLocaleConverter(), Date.class);
        BeanUtils.setProperty(p, "name", name);
        // 转换器(String --> int)
        // 但是只支持八种基本数据类型的转换
        // 如果要转换其他的类型，可以自定义转换器
        BeanUtils.setProperty(p, "age", age);
        // 错误，只支持八种基本数据类型转换
        BeanUtils.setProperty(p, "birthday", birthday);

        System.out.println(p.getName() + "   " + p.getAge() + "   "
                + p.getBirthday().toLocaleString());
    }
}

附上jar下载地址

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beanutils
commons-logging