文章目录
【Java对象转换】002- Java 对象与 Map 互转
一、Java 对象与 Map 概述
1、Java 对象
- Java对象是数据定制网站和处理可用数据的过程的组合；
- 对象既有状态又有行为 。 在Java中，定制网站使用关键字“ new”创建对象；
- 定制网站对象是从称为类的模板创建的；
- 定制网站对象是类的实例。
2、Map
定制网站参考本人文章：使用详解 https://blog.csdn.net/qq_29689343/article/details/109853787
二、Java 对象与 Map 互转
定制网站下面的工具类在具体使定制网站用的时候需要做具体调整，定制网站比如捕捉异常！
1、使用 commons. 转换
第一步：在 pom.xml 定制网站下引入依赖
<dependency> <groupId>commons-beanutils</groupId> <artifactId>commons-beanutils</artifactId> <version>1.9.4</version></dependency>- 1
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第二步：写个工具类
package com.zibo.study.object_switch.beanutils;import org.apache.commons.beanutils.BeanMap;import org.apache.commons.beanutils.BeanUtils;import java.util.Map;public class ObjectAndMapUtil { private ObjectAndMapUtil() {} // map 转 java 对象 public static <T> T mapToObject(Map<String, Object> map, Class<T> clazz) throws Exception { if (map == null) { return null; } T t = clazz.newInstance(); BeanUtils.populate(t, map); return t; } // java 对象转 map public static Map<?, ?> objectToMap(Object obj) { if (obj == null) return null; return new BeanMap(obj); }}- 1
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第三步：代码演示
package com.zibo.study.object_switch.beanutils;import java.util.Arrays;import java.util.HashMap;import java.util.Map;public class Main { public static void main(String[] args) { // 1、创建 Java 对象 Dog dog = new Dog("瓦豆", 2, 20.5, Arrays.asList("吃骨头", "玩球")); // 2、使用工具类转 map System.out.println("2、使用工具类转 map"); Map<?, ?> dogMap = ObjectAndMapUtil.objectToMap(dog); System.out.println(dogMap.get("name")); System.out.println(dogMap.get("age")); System.out.println(dogMap.get("weight")); System.out.println(dogMap.get("hobbies")); // 3、使用工具类转 object System.out.println("3、使用工具类转 object"); try { Map<String, Object> map = new HashMap<>(); map.put("name", "瓦豆"); map.put("age", 2); map.put("weight", 20.5); map.put("hobbies", Arrays.asList("吃骨头", "玩球")); Dog mapToDog = ObjectAndMapUtil.mapToObject(map, Dog.class); // Dog mapToDog = ObjectAndMapUtil.mapToObject((Map<String, Object>) dogMap, Dog.class); System.out.println(mapToDog); } catch (Exception e) { e.printStackTrace(); } }}- 1
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第四步：运行结果
2、使用工具类转 map瓦豆220.5[吃骨头, 玩球]3、使用工具类转 object（中间忽略了一些日志）Dog(name=瓦豆, age=2, weight=20.5, hobbies=[吃骨头, 玩球])- 1
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2、使用Introspector转换
第一步：写个工具类
package com.zibo.study.object_switch.beanutils;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;import java.util.HashMap;import java.util.Map;public class ObjectAndMapUtil2 { // map 转 java 对象 public static <T> T mapToObject(Map<String, Object> map, Class<T> clazz) throws IntrospectionException, InstantiationException, IllegalAccessException, InvocationTargetException { if (map == null) return null; T t = clazz.newInstance(); BeanInfo beanInfo = Introspector.getBeanInfo(t.getClass()); PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors(); for (PropertyDescriptor property : propertyDescriptors) { Method setter = property.getWriteMethod(); if (setter != null) setter.invoke(t, map.get(property.getName())); } return t; } // java 对象转 map public static Map<String, Object> objectToMap(Object obj) throws IntrospectionException, InvocationTargetException, IllegalAccessException { if (obj == null) return null; Map<String, Object> map = new HashMap<>(); BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass()); PropertyDescriptor[] propertyDescriptors = beanInfo .getPropertyDescriptors(); for (PropertyDescriptor property : propertyDescriptors) { String key = property.getName(); if (key.compareToIgnoreCase("class") == 0) continue; Method getter = property.getReadMethod(); Object value = getter != null ? getter.invoke(obj) : null; map.put(key, value); } return map; }}- 1
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第二步：代码演示
package com.zibo.study.object_switch.beanutils;import java.util.Arrays;import java.util.HashMap;import java.util.Map;public class Main { public static void main(String[] args) throws Exception { // 1、创建 Java 对象 Dog dog = new Dog("瓦豆", 2, 20.5, Arrays.asList("吃骨头", "玩球")); // 2、使用工具类转 map System.out.println("2、使用工具类转 map"); Map<?, ?> dogMap = ObjectAndMapUtil2.objectToMap(dog); System.out.println(dogMap.get("name")); System.out.println(dogMap.get("age")); System.out.println(dogMap.get("weight")); System.out.println(dogMap.get("hobbies")); // 3、使用工具类转 object System.out.println("3、使用工具类转 object"); try { Map<String, Object> map = new HashMap<>(); map.put("name", "瓦豆"); map.put("age", 2); map.put("weight", 20.5); map.put("hobbies", Arrays.asList("吃骨头", "玩球")); Dog mapToDog = ObjectAndMapUtil2.mapToObject(map, Dog.class); // Dog mapToDog = ObjectAndMapUtil.mapToObject((Map<String, Object>) dogMap, Dog.class); System.out.println(mapToDog); } catch (Exception e) { e.printStackTrace(); } }}- 1
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第三步：运行结果
2、使用工具类转 map瓦豆220.5[吃骨头, 玩球]3、使用工具类转 objectDog(name=瓦豆, age=2, weight=20.5, hobbies=[吃骨头, 玩球])- 1
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3、使用reflect转换
第一步：写个工具类
package com.zibo.study.object_switch.beanutils;import java.lang.reflect.Field;import java.lang.reflect.Modifier;import java.util.HashMap;import java.util.Map;public class ObjectAndMapUtil3 { // map 转 java 对象 public static <T> T mapToObject(Map<String, Object> map, Class<T> clazz) throws InstantiationException, IllegalAccessException { if (map == null) return null; T t = clazz.newInstance(); Field[] fields = clazz.getDeclaredFields(); for (Field field : fields) { int mod = field.getModifiers(); if (Modifier.isFinal(mod) || Modifier.isStatic(mod)) continue; field.setAccessible(true); field.set(t, map.get(field.getName())); } return t; } // java 对象转 map public static Map<String, Object> objectToMap(Object obj) throws IllegalAccessException { if (obj == null) return null; Map<String, Object> map = new HashMap<>(); Field[] declaredFields = obj.getClass().getDeclaredFields(); for (Field field : declaredFields) { field.setAccessible(true); map.put(field.getName(), field.get(obj)); } return map; }}- 1
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第二步：代码演示
package com.zibo.study.object_switch.beanutils;import java.util.Arrays;import java.util.HashMap;import java.util.Map;public class Main { public static void main(String[] args) throws Exception { // 1、创建 Java 对象 Dog dog = new Dog("瓦豆", 2, 20.5, Arrays.asList("吃骨头", "玩球")); // 2、使用工具类转 map System.out.println("2、使用工具类转 map"); Map<?, ?> dogMap = ObjectAndMapUtil3.objectToMap(dog); System.out.println(dogMap.get("name")); System.out.println(dogMap.get("age")); System.out.println(dogMap.get("weight")); System.out.println(dogMap.get("hobbies")); // 3、使用工具类转 object System.out.println("3、使用工具类转 object"); try { Map<String, Object> map = new HashMap<>(); map.put("name", "瓦豆"); map.put("age", 2); map.put("weight", 20.5); map.put("hobbies", Arrays.asList("吃骨头", "玩球")); Dog mapToDog = ObjectAndMapUtil3.mapToObject(map, Dog.class); // Dog mapToDog = ObjectAndMapUtil.mapToObject((Map<String, Object>) dogMap, Dog.class); System.out.println(mapToDog); } catch (Exception e) { e.printStackTrace(); } }}- 1
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第三步：运行结果
2、使用工具类转 map瓦豆220.5[吃骨头, 玩球]3、使用工具类转 objectDog(name=瓦豆, age=2, weight=20.5, hobbies=[吃骨头, 玩球])- 1
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4、使用 net.sf..beans.BeanMap 转换
第一步：在 pom.xml 下引入依赖
<dependency> <groupId>cglib</groupId> <artifactId>cglib</artifactId> <version>3.3.0</version></dependency>- 1
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第二步：写个工具类
package com.zibo.study.object_switch.beanutils;import com.google.common.collect.Maps;import net.sf.cglib.beans.BeanMap;import java.util.Map;public class ObjectAndMapUtil4 { // map 转 java 对象 public static <T> T mapToObject(Map<String, Object> map, Class<T> clazz) throws InstantiationException, IllegalAccessException { T t = clazz.newInstance(); BeanMap beanMap = BeanMap.create(t); beanMap.putAll(map); return t; } // java 对象转 map public static Map<String, Object> objectToMap(Object obj) { if (obj == null) return null; Map<String, Object> map = Maps.newHashMap(); BeanMap beanMap = BeanMap.create(obj); for (Object key : beanMap.keySet()) { map.put(key + "", beanMap.get(key)); } return map; }}- 1
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第三步：代码演示
package com.zibo.study.object_switch.beanutils;import java.util.Arrays;import java.util.HashMap;import java.util.Map;public class Main { public static void main(String[] args) { // 1、创建 Java 对象 Dog dog = new Dog("瓦豆", 2, 20.5, Arrays.asList("吃骨头", "玩球")); // 2、使用工具类转 map System.out.println("2、使用工具类转 map"); Map<?, ?> dogMap = ObjectAndMapUtil4.objectToMap(dog); System.out.println(dogMap.get("name")); System.out.println(dogMap.get("age")); System.out.println(dogMap.get("weight")); System.out.println(dogMap.get("hobbies")); // 3、使用工具类转 object System.out.println("3、使用工具类转 object"); try { Map<String, Object> map = new HashMap<>(); map.put("name", "瓦豆"); map.put("age", 2); map.put("weight", 20.5); map.put("hobbies", Arrays.asList("吃骨头", "玩球")); Dog mapToDog = ObjectAndMapUtil4.mapToObject(map, Dog.class); // Dog mapToDog = ObjectAndMapUtil.mapToObject((Map<String, Object>) dogMap, Dog.class); System.out.println(mapToDog); } catch (Exception e) { e.printStackTrace(); } }}- 1
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第四步：运行结果
2、使用工具类转 map瓦豆220.5[吃骨头, 玩球]3、使用工具类转 objectDog(name=瓦豆, age=2, weight=20.5, hobbies=[吃骨头, 玩球])- 1
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5、使用 json 转换
第一步：在 pom.xml 下引入依赖
<dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.80</version></dependency>- 1
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第二步：写一个工具类
package com.zibo.study.object_switch.beanutils;import com.alibaba.fastjson.JSONObject;import java.util.Map;public class ObjectAndMapUtil5 { // map 转 java 对象 public static <T> T mapToObject(Map<String, Object> map, Class<T> clazz) { String jsonStr = JSONObject.toJSONString(map); return JSONObject.parseObject(jsonStr, clazz); } // java 对象转 map public static Map<String, Object> objectToMap(Object obj) { if(obj == null) return null; String jsonStr = JSONObject.toJSONString(obj); return JSONObject.parseObject(jsonStr); }}- 1
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第三步：代码演示
package com.zibo.study.object_switch.beanutils;import java.util.Arrays;import java.util.HashMap;import java.util.Map;public class Main { public static void main(String[] args) { // 1、创建 Java 对象 Dog dog = new Dog("瓦豆", 2, 20.5, Arrays.asList("吃骨头", "玩球")); // 2、使用工具类转 map System.out.println("2、使用工具类转 map"); Map<?, ?> dogMap = ObjectAndMapUtil5.objectToMap(dog); System.out.println(dogMap.get("name")); System.out.println(dogMap.get("age")); System.out.println(dogMap.get("weight")); System.out.println(dogMap.get("hobbies")); // 3、使用工具类转 object System.out.println("3、使用工具类转 object"); try { Map<String, Object> map = new HashMap<>(); map.put("name", "瓦豆"); map.put("age", 2); map.put("weight", 20.5); map.put("hobbies", Arrays.asList("吃骨头", "玩球")); Dog mapToDog = ObjectAndMapUtil5.mapToObject(map, Dog.class); // Dog mapToDog = ObjectAndMapUtil.mapToObject((Map<String, Object>) dogMap, Dog.class); System.out.println(mapToDog); } catch (Exception e) { e.printStackTrace(); } }}- 1
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第四步：运行结果
2、使用工具类转 map瓦豆220.5["吃骨头","玩球"]3、使用工具类转 objectDog(name=瓦豆, age=2, weight=20.5, hobbies=[吃骨头, 玩球])- 1
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三、 后记
暂仅记录这么多，后续若有更好的方法会进行补充！
参考文章：https://blog.csdn.net/liuyunyihao/article/details/86597002