这篇文章给大家分享的是有关Java怎么实现实体类转Map、Map转实体类的内容。小编觉得挺实用的,因此分享给大家做个参考,一起跟随小编过来看看吧。实体类转Map、Map转实体类1、创建entity(User.java)package&nbs
这篇文章给大家分享的是有关Java怎么实现实体类转Map、Map转实体类的内容。小编觉得挺实用的,因此分享给大家做个参考,一起跟随小编过来看看吧。
package com.jeff.entity;public class User { private String userName; private String passWord; private Integer age; public User() { super(); } public User(String userName, String password, Integer age) { super(); this.userName = userName; this.password = password; this.age = age; } 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 Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } @Override public String toString() { return "User [userName=" + userName + ", password=" + password + ", age=" + age + "]"; }}
package com.jeff.utils;import java.lang.reflect.Field;import java.util.HashMap;import java.util.Map;public class EntityUtils { public static Map<String, Object> entityToMap(Object object) { Map<String, Object> map = new HashMap<>(); for (Field field : object.getClass().getDeclaredFields()) { try { boolean flag = field.isAccessible(); field.setAccessible(true); Object o = field.get(object); map.put(field.getName(), o); field.setAccessible(flag); } catch (Exception e) { e.printStackTrace(); } } return map; } public static <T> T mapToEntity(Map<String, Object> map, Class<T> entity) { T t = null; try { t = entity.newInstance(); for (Field field : entity.getDeclaredFields()) { if (map.containsKey(field.getName())) { boolean flag = field.isAccessible(); field.setAccessible(true); Object object = map.get(field.getName()); if (object != null && field.getType().isAssignableFrom(object.getClass())) { field.set(t, object); } field.setAccessible(flag); } } return t; } catch (InstantiationException e) { e.printStackTrace(); } catch (IllegalAccessException e) { e.printStackTrace(); } return t; }}
package com.jeff;import java.util.HashMap;import java.util.Map;import com.jeff.entity.User;import com.jeff.utils.EntityUtils;public class TestCopyObj3 { public static void main(String[] args) throws Exception { Map<String, Object> map = new HashMap<String, Object>(); map.put("userName", "Jeff"); map.put("password", "123456"); map.put("age", 18); System.out.println("Map对象:" + map); User user = EntityUtils.mapToEntity(map, User.class); System.out.println("User对象:" + user); }}
package com.jeff;import java.util.Map;import com.jeff.entity.User;import com.jeff.utils.EntityUtils;public class TestCopyObj4 {public static void main(String[] args) throws Exception {User user = new User("Jeff", "123456", 18);System.out.println("User对象:" + user);Map<String, Object> map = EntityUtils.entityToMap(user);System.out.println("Map对象:" + map);}}
因为做项目,需要取出复杂的map里的value转为实体类对象和List,在博客里找了很久没有找到合适的方法,于是只能默默探索。。。
map里包含了实体类,list数组,还有普通的key-value,取出我们想要的数据呢?直接取我是取不出来,后来想先转JSON,在从json里去出对象和list,然后就这么干,废话少说,撸代码!!!
<!--alibaba json --><dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.46</version></dependency>
import com.alibaba.fastjson.JSON;import com.alibaba.fastjson.JSONArray;import com.alibaba.fastjson.JSONObject;import java.util.List;import java.util.Map;public class JsonUtil<T>{ public static JSONObject mapToJson(Map<String, Object> map) { String data = JSON.toJSONString(map); return JSON.parseObject(data); } public String mapToString(Map<String, Object> map, String key) { JSONObject jsonObject = mapToJson(map); return jsonObject.getString(key); } public static <T> T mapToObject(Map<String, Object> map, Class<T> clazz, String key) { T t = null; JSONObject jsonObject = mapToJson(map); JSONObject object = jsonObject.getJSONObject(key); t = object.toJavaObject(clazz); return t; } public List<T> mapToList(Map<String, Object> map, Class<T> clazz, String key) { List<T> t = null; JSONObject jsonObject = mapToJson(map); JSONArray array = jsonObject.getJSONArray(key); t = array.toJavaList(clazz); return t; }}
@RequestMapping(value = "/subjects/subject", method = {RequestMethod.POST}) public Result addSubject(@RequestBody Map<String, Object> map) { //使用json JsonUtil jsonUtil = new JsonUtil(); //获取Subject对象 Subject subject = jsonUtil.mapToObject(map, Subject.class, "subject"); //获取List数组 List<Progress> progressList = jsonUtil.mapToList(map, Progress.class, "progress"); //获取key对应的值 String specid = jsonUtil.mapToString(map, "specid"); //打印输出 System.out.println(subject); for(Progress progress : progressList) { System.out.println(progress); } System.out.println(specid); return null; }
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