BeanUtils组件学习笔记

目录：

1.什么是BeanUtils组件
2.导入jar包
3.如何使用BeanUtils
4.在Servelt中使用BeanUtils组件处理请求的封装

1.什么是BeanUtils组件？

BeanUtils是apache提供的一套开源的api，方便对javabean进行操作

2.导入jar包

1.引入：commons-beanutils-1.8.3.jar 核心包

2.引入：commons-logging-1.1.3.jar 日志包

百度云链接: https://pan.baidu.com/s/1c2vhE3u 密码: d6x9

3.如何使用BeanUtils

• 首先要写一个javaBean文件

package com.huan.beans;

import java.util.Date;

/**
 * Created by pc on 17-5-10.
 */
public class Admin {
    private String username;
    private String password;
    private int age;
    private Date brith;

    public Date getBrith() {
        return brith;
    }

    public void setBrith(Date brith) {
        this.brith = brith;
    }



    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

1).对象属性的拷贝

对基本数据类型，会自动进行类型转换

package com.huan.beans;

import org.apache.commons.beanutils.BeanUtils;
import org.junit.Test;

import java.lang.reflect.InvocationTargetException;

/**
 * Created by pc on 17-5-10.
 */
public class App {
    @Test
   public void test () throws Exception {
        //基本实现
       Admin admin = new Admin();
//       admin.setUsername("mahuan");
//       admin.setPassword("123456");
       //BeanUtils组件实现对象属性的拷贝（两种写法）
        BeanUtils.copyProperty(admin,"username","mahuan");
        BeanUtils.setProperty(admin,"password","123456");

        System.out.println(admin.getUsername());
        System.out.println(admin.getPassword());
   }
}

2).对象的拷贝

package com.huan.beans;

import org.apache.commons.beanutils.BeanUtils;
import org.junit.Test;

import java.lang.reflect.InvocationTargetException;

/**
 * Created by pc on 17-5-10.
 */
public class App {
    @Test
   public void test () throws Exception {
        //基本实现
       Admin admin = new Admin();
//       admin.setUsername("mahuan");
//       admin.setPassword("123456");
       //BeanUtils组件实现对象属性的拷贝
        BeanUtils.copyProperty(admin,"username","mahuan");
        BeanUtils.setProperty(admin,"password","123456");
       
        //拷贝对象
        Admin newAdmin = new Admin();
        BeanUtils.copyProperties(newAdmin,admin );
        System.out.println(newAdmin.getUsername());
        System.out.println(newAdmin.getPassword());
   }
}

3).map数据拷贝到对象中

map中key要和javaBean中的属性一致

@Test
  public void test2() throws Exception {
       Admin adminMap = new Admin();
      Map<String,Object> map = new HashMap<String,Object>();
      map.put("username","xiaoming");
      map.put("age",22);
      BeanUtils.populate(adminMap,map);
      System.out.println(adminMap.getUsername());
      System.out.println(adminMap.getAge());
  }

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4).日期类型转换器

• （1）自定义

  @Test
   public void test3() throws Exception {
       String name = "xiaohuan";
       int age = 20;
       String birth = "1995-09-09";
       //注册日期类转换器
       //方式1.自定义
       ConvertUtils.register(new Converter() {
           public Object convert(Class aClass, Object o) {
               if (aClass != Date.class) {
                   return null;
               }
               if (o == null || "".equals(o.toString().trim())) {
                   return null;
               }
               try {
                   SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
                   return sdf.parse(o.toString());
               } catch (ParseException e) {
                   e.printStackTrace();
               }
                   return null;
           }

       }, Date.class);
       Admin adminData = new Admin();
       BeanUtils.copyProperty(adminData, "username", name);
       BeanUtils.copyProperty(adminData, "age", age);
       BeanUtils.copyProperty(adminData, "brith", birth);

       System.out.println(adminData.getBrith());
   }

• （2）使用组件实现日期类型转换器

 @Test
    public void test3() throws Exception {
        String name = "xiaohuan";
        int age = 20;
        String birth = "1995-09-09";
        //注册日期类转换器
        //方式1.使用组件
        ConvertUtils.register(new DateLocaleConverter(),Date.class);

        Admin adminData = new Admin();
        BeanUtils.copyProperty(adminData, "username", name);
        BeanUtils.copyProperty(adminData, "age", age);
        BeanUtils.copyProperty(adminData, "brith", birth);

        System.out.println(adminData.getBrith());
    }

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4.在Servelt中使用BeanUtils组件处理请求的封装

• 在servlet中调用封装好的数据处理

Admin admin = wecUtils.copyToBean(request,Admin.class);

• 新建webUtils.java文件

  package com.huan.beans;

import org.apache.commons.beanutils.BeanUtils;
import javax.servlet.http.HttpServletRequest;
import java.util.Enumeration;

/**
 * Created by pc on 17-5-10.
 */
public class WebUtils {
    public static <T> T copyToBean(HttpServletRequest request, Class<T> tClass){
        try {
            T t = tClass.newInstance();
            Enumeration<String> enums = request.getParameterNames();
            while (enums.hasMoreElements()) {
                String name = enums.nextElement();
                String value = request.getParameter(name);
                BeanUtils.copyProperty(t, name, value);
            }
        }catch (Exception e){
            throw new RuntimeException(e);
        }
        return null;
    }
}

文章文集：JavaEE--学习笔记