java-Map和实体模型类和json的相互转化（运用反射）

冷不防 2023-11-02 06:56 140阅读 0赞

### 实体模型类： ###

public class model {
    
    	private String Name1;
    	private String Name2;
    	private String Name3;
    	public model() {
    		super();
    	}
    	public model(String name1, String name2, String name3) {
    		super();
    		Name1 = name1;
    		Name2 = name2;
    		Name3 = name3;
    	}
    	@Override
    	public String toString() {
    		return "model [Name1=" + Name1 + ", Name2=" + Name2 + ", Name3="
    				+ Name3 + "]";
    	}
    	public String getName1() {
    		return Name1;
    	}
    	public void setName1(String name1) {
    		Name1 = name1;
    	}
    	public String getName2() {
    		return Name2;
    	}
    	public void setName2(String name2) {
    		Name2 = name2;
    	}
    	public String getName3() {
    		return Name3;
    	}
    	public void setName3(String name3) {
    		Name3 = name3;
    	}
    	
    }

###  ###

### 实体类转map： ###

public class Map_ModelUtil {
             /**  实体类转化成Map
    	 * @param classModel
    	 * @return
    	 */
    	public static Map ClassToMap( Object classModel) {
    		Object temp = classModel;
    		Map<Object,Object> map = new HashMap<Object, Object>();
    		Class<?> clz = temp.getClass();
    		Field[] fields = clz.getDeclaredFields();
    		for (Field field : fields) {
    			field.setAccessible(true);
    			try {
    				map.put(field.getName(), field.get(temp));//键值对为  属性名：属性值
    			} catch (Exception e) {
    				System.out.println("转换异常：" + e.getMessage());
    			}
    		}
    		return map;
    	}
    }

**测试：**

public static void main(String[] args) {
    		model test = new model("value1","value2","value3");
    		System.out.println(Map_ModelUtil.ClassToMap(test));
            }

**结果：**

{Name3=value3, Name2=value2, Name1=value1}

### Map转实体类： ###

public class Map_ModelUtil {
    
    	/** map转化成实体类
    	 * @param map
    	 * @param classModel
    	 * @return
    	 */
    	public static Object MapToClassp( Map map , Object classModel) {
    		Map<Object,Object> tempMap = map;
    		Object tempClass = classModel;
    		Class<?> clz = tempClass.getClass();
    		Field[] fields = clz.getDeclaredFields();
    		for (Field field : fields) {
    			field.setAccessible(true);
    			try {
    				if (tempMap.containsKey(field.getName())) { //如果map集合存在与属性名相同的键
    					field.set(tempClass, tempMap.get(field.getName())); //把属性值赋予给目标类对应属性
    				}
    			} catch (Exception e) {
    				System.out.println("转换异常：" + e.getMessage());
    			}
    		}
    		return tempClass;
    	}
    	
    
    }

**测试：**

public static void main(String[] args) {
    		Map<String,String> test = new HashMap<String, String>();
    		test.put("Name1", "value1");
    		test.put("Name2", "value2");
    		test.put("Name3", "value3");
    		System.out.println(Map_ModelUtil.MapToClassp(test, new model()).toString());
    	}

**结果：**

model [Name1=value1, Name2=value2, Name3=value3]

## Map转JSON： ##

/** map转化成Json数据
    	 * @param map
    	 * @param classModel
    	 * @return
    	 */
    	public static JSONObject mapToJson( Map map  ) { 
    		Set<Entry<Object, Object>> dataEntrys = map.entrySet();
    		JSONObject jsonObject = new JSONObject();
    		
    		for (Entry<Object, Object> data : dataEntrys) { 
    			System.out.println("key:" + data.getKey() + " --- value:" + data.getValue());
    			jsonObject.put((String) data.getKey(), data.getValue());
    		}
    		
    		return jsonObject;
    	}

**测试：**

public static void main(String[] args) { 
    		
    		Map<String, String> datas = new HashMap<String, String>();
    		datas.put("key1", "value1");
    		datas.put("key2", "value2");
    		datas.put("key3", "value3");
    		JSONObject result = mapToJson(datas );
    		System.out.println(result);
    		}

**结果：**

key:key1 --- value:value1
    key:key2 --- value:value2
    key:key3 --- value:value3
    {"key1":"value1","key2":"value2","key3":"value3"}

## JSON转Map： ##

/** Json转化成map数据
    	 * @param map
    	 * @param classModel
    	 * @return
    	 */
    	public static Map jsonToMap(  String jsonString ) { 
    		Map<Object, Object> result = new HashMap<Object, Object>();
    		JSONObject json = JSON.parseObject(jsonString);  
    		Set<String> setList = json.keySet(); 
    		for (String data : setList) { 
    			System.out.println("key:" + data + " --- value:" + json.get(data));
    			result.put(data, json.get(data));
    		} 
    		return result;
    	}

**测试：**

public static void main(String[] args) { 
    		 
    		Map mapMsg = jsonToMap("{\"key1\":\"value1\",\"key2\":\"value2\",\"key3\":\"value3\"}");
    		System.out.println("mapMsg:" + mapMsg);
    		
    		}

**结果：**

key:key1 --- value:value1
    key:key2 --- value:value2
    key:key3 --- value:value3
    mapMsg:{key1=value1, key2=value2, key3=value3}

## JSON转实体类： ##

/** Json转化成model数据
    	 * @param map
    	 * @param classModel
    	 * @return
    	 */
    	public static Object jsonToModel(  String jsonString , Object classA ) {  
    		try{
    			JSONObject json = JSON.parseObject(jsonString);  
    			Set<String> setList = json.keySet(); 
    			for (String data : setList) { 
    				System.out.println("key:" + data + " --- value:" + json.get(data));
    				 Field value = classA.getClass().getDeclaredField(data);//在目标类中查看是否有相同名称的属性
    	             value.setAccessible(true);
    	             value.set(classA, json.get(data)); //把属性值赋予给目标类对应属性
    			} 
    			return classA;
    		}catch (Exception e) {
    			System.out.println("转化异常！");
    			return null;
    		}
    	}

**测试：**

public static void main(String[] args) { 
    	 
    		model model = (model) jsonToModel("{\"Name1\":\"value1\",\"Name2\":\"value2\",\"Name3\":\"value3\"}" , new model() );
    		System.out.println(model.toString());
    
            //JSON也有自带的转化方法
            model model2 = JSON.parseObject("{\"Name1\":\"value1\",\"Name2\":\"value2\",\"Name3\":\"value3\"}" , model.getClass() );
     		System.out.println("model2:" + model.toString());
    	}

**结果：**

key:Name3 --- value:value3
    key:Name1 --- value:value1
    key:Name2 --- value:value2
    model [Name1=value1, Name2=value2, Name3=value3]
    model2:model [Name1=value1, Name2=value2, Name3=value3]

## 实体类转JSON： ##

这里不写了，这个用 JSON 自带的方法 JSON.toJSONString(model2); 就可以了，返回的就是 json 的字符串；

#### 在系统的开发中，有时候我们需要把实体类的每一个属性名和值都拿出来，如果靠传统的get方法和手写的属性名，效率低而且复用性差，尤其是当出现一个模型有几十上百个属性字段时，一个一个写简直浪费时间，用这个转化，把实体类的属性名和属性值直接转化成键值对，方便遍历。 ####