java工具类-bean转map-白红宇

java工具类-bean转map

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发布时间：2019-05-27

本文共 4959 字，大约阅读时间需要 16 分钟。

工作常常遇到将java的Bean对象转化为Map，或者将Map转为Bean对象。

常见的手段

通过json工具，将Bean转json，再将json转Map

效率低

jdk的反射，获取类的属性，进行转化

比较麻烦，书写代码比较多

通过工具类BeanMap来完成

效率高，底层也是基于反射，不过做了些优化，比如缓存等手段 (推荐)

通过Apache的BeanUtils来完成

bean转化map是Map<String, String>类型

循环转化1w次，对比下BeanMap和BeanUtils的耗时(毫秒)

方式	bean转map	map转bean
BeanMap	593	364
BeanUtils	1254	2430

由上测试结果，我们可以看出BeanMap效率高，所以推荐使用BeanMap

更多内容可以关注：

1.BeanMap方式

BeanMap是org.springframework.cglib.beans.BeanMap，在springcore中

1-1.工具类BeanMapTool

package com.iworkh.test.restassured.utils;import org.springframework.cglib.beans.BeanMap;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;/** * bean和map互转 * * @author: iworkh-沐雨云楼 * @date: 2020-06-18 */public class BeanMapTool {
       public static 
   
     Map
    
      beanToMap(T bean) {
           BeanMap beanMap = BeanMap.create(bean);        Map
     
       map = new HashMap<>();        beanMap.forEach((key, value) -> {
               map.put(String.valueOf(key), value);        });        return map;    }    public static 
      
        T mapToBean(Map
       
         map, Class
        
          clazz) throws IllegalAccessException, InstantiationException { T bean = clazz.newInstance(); BeanMap beanMap = BeanMap.create(bean); beanMap.putAll(map); return bean; } public static 
         
           List
          
           
            > objectsToMaps(List
            
              objList) { List
             
              
               > list = new ArrayList<>(); if (objList != null && objList.size() > 0) { Map
               
                 map = null; T bean = null; for (int i = 0, size = objList.size(); i < size; i++) { bean = objList.get(i); map = beanToMap(bean); list.add(map); } } return list; } public static 
                
                  List
                 
                   mapsToObjects(List
                  
                   
                    > maps, Class
                    
                      clazz) throws InstantiationException, IllegalAccessException { List
                     
                       list = new ArrayList<>(); if (maps != null && maps.size() > 0) { Map
                      
                        map = null; for (int i = 0, size = maps.size(); i < size; i++) { map = maps.get(i); T bean = mapToBean(map, clazz); list.add(bean); } } return list; }}

1-2.调用

public class BeanMapToolTest {
       @Test    public void testBeanToMap() {
           String[] hobbies = {
   "football", "sing"};        UserVo user = new UserVo(1, "zhangsan", System.currentTimeMillis(), false, Arrays.asList(hobbies));        Map
   
     map = BeanMapTool.beanToMap(user);        System.out.println(map.get("name"));    }    @Test    public void testMapToBean() {
           String[] hobbies = {
   "football", "sing"};        Map
    
      map = new HashMap<>();        map.put("id", 1);        map.put("name", "zhangsan");        map.put("birthday", System.currentTimeMillis());        map.put("vip", false);        map.put("hobbies", Arrays.asList(hobbies));        try {
               UserVo userVo = BeanMapTool.mapToBean(map, UserVo.class);            System.out.println(userVo.getHobbies());        } catch (IllegalAccessException | InstantiationException e) {
               e.printStackTrace();        }    }}

2.BeanUtils方式

导入pom依赖


       
    
     commons-beanutils
        
    
     commons-beanutils
        
    
     1.9.3

2-1.工具类BeanUtilsTool

package com.iworkh.test.restassured.utils;import org.apache.commons.beanutils.BeanUtils;import java.lang.reflect.InvocationTargetException;import java.util.Map;/** * Apache BeanUtils工具类 * * @author: iworkh-沐雨云楼 * @date: 2020-06-19 */public class BeanUtilsTool {
       public static 
   
     Map
    
      beanToMap(T bean)            throws IllegalAccessException, NoSuchMethodException, InvocationTargetException {
           return BeanUtils.describe(bean);    }    public static 
     
       T mapToBean(Map
      
        map, Class
       
         bean)            throws IllegalAccessException, InstantiationException, InvocationTargetException {
           T t = bean.newInstance();        BeanUtils.populate(t, map);        return t;    }}

2-2.调用

public class BeanUtilsToolTest {
       @Test    public void testBeanToMap() {
           String[] hobbies = {
   "football", "sing"};        UserVo user = new UserVo(1, "zhangsan", System.currentTimeMillis(), false, Arrays.asList(hobbies));        try {
               Map
   
     map = BeanUtilsTool.beanToMap(user);            System.out.println(map.get("name"));        } catch (IllegalAccessException | NoSuchMethodException | InvocationTargetException e) {
               e.printStackTrace();        }    }    @Test    public void testMapToBean() {
           String[] hobbies = {
   "football", "sing"};        Map
    
      map = new HashMap<>();        map.put("id", 1);        map.put("name", "zhangsan");        map.put("birthday", System.currentTimeMillis());        map.put("vip", false);        map.put("hobbies", Arrays.asList(hobbies));        try {
               UserVo userVo = BeanUtilsTool.mapToBean(map, UserVo.class);            System.out.println(userVo.getHobbies());        } catch (IllegalAccessException | InstantiationException | InvocationTargetException e) {
               e.printStackTrace();        }    }}