JAVA 对象转换为JSON

蔚落 2024-03-23 23:06 33阅读 0赞

转载：[如何把java对象转换为json java对象怎么转成json\_clghxq的技术博客\_51CTO博客][java_json java_json_clghxq_51CTO]

1、Java对象列表转换为JSON对象数组，并转为字符串

JSONArray jsonArray = JSONArray.fromObject(list);  
String jsonArrayStr = jsonArray.toString();

2、把Java对象转换成JSON对象，并转化为字符串

JSONObject jsonObject = JSONObject.fromObject(obj);  
String jsonObjectStr = jsonObject.toString();

3、过滤不需要转换为JSON格式的属性

使用jsonConfig对象的setExcludes()方法，传入参数为待过滤属性组成的数组。

JsonConfig cfg = new JsonConfig();  
cfg.setExcludes(new String\[\] \{“待过滤属性1”, “待过滤属性2”, ..., “待过滤属性n”\});

4. json转bean

JSONObject.toBean(targetJson, targetClass);

5、实例

package com.ajax.test;  
import java.util.ArrayList;  
import java.util.List;  
import com.fasterxml.jackson.core.JsonProcessingException;  
import net.sf.json.JSONArray;  
import net.sf.json.JSONObject;  
import net.sf.json.JsonConfig;  
public class Customer \{  
public Customer(String name, String id) \{  
super();  
this.name = name;  
this.id = id;  
\}  
private String name;  
private String id;  
public String getName() \{  
return name;  
\}  
public void setName(String name) \{  
this.name = name;  
\}  
public String getId() \{  
return id;  
\}  
public void setId(String id) \{  
this.id = id;  
\}  
public static void main(String\[\] args) throws JsonProcessingException \{  
//包含多个对象的List集合转换为JSON格式  
List<Customer> list = new ArrayList<Customer>();  
Customer c1 = new Customer("Alice", "001");  
Customer c2 = new Customer("Bruce", "002");  
Customer c3 = new Customer("Cindy", "003");  
list.add(c1);  
list.add(c2);  
list.add(c3);  
JsonConfig config1 = new JsonConfig();  
//过滤List集合中的Customer对象的id属性不生成JSON  
config1.setExcludes(new String\[\] \{"id"\});  
JSONArray jsonArray = JSONArray.fromObject(list, config1);  
System.out.println(jsonArray.toString());  
//一个对象转换为JSON格式  
Customer c = new Customer("Boss", "004");  
JsonConfig config2 = new JsonConfig();  
//过滤Customer对象的id属性不生成JSON  
config2.setExcludes(new String\[\] \{"id"\});  
JSONObject jsonObject = JSONObject.fromObject(c, config2);  
System.out.println(jsonObject.toString());  
\}  
\}

6.将父类对象转化为子类对象：

创建父类实例，将父类实例化

将子类实例转化成json

将父类实例转化成json

遍历父类json实例，使用子类json获取vaule值，设置到父类json中。

代码如下：

public static Object createBeanWith(Class targetClass, Object source) {
            Object target = null;
            try {
                target = targetClass.newInstance();
            } catch (Exception e) {
                return null;
            }
            JSONObject targetJson = JSONObject.fromObject(target);
            JSONObject sourceJson = JSONObject.fromObject(source);
            for (Object key : targetJson.keySet()) {
                if (sourceJson.containsKey(key)) {
                    targetJson.put(key, sourceJson.get(key));
                }
            }
            return JSONObject.toBean(targetJson, targetClass);
        }

精简写法：

Object result = JSONObject.parseObject(JSONObject.toJSONString(source), targetClass);

maven依赖的包：

<dependency>
        <groupId>net.sf.json-lib</groupId>
        <artifactId>json-lib</artifactId>
        <version>2.4</version>
        <classifier>jdk15</classifier>
    </dependency>
    
    <dependency>
        <groupId>org.json</groupId>
        <artifactId>json</artifactId>
        <version>20230227</version>
    </dependency>
    
    <dependency>
        <groupId>net.sf.ezmorph</groupId>
        <artifactId>ezmorph</artifactId>
        <version>1.0.6</version>
    </dependency>
    
    
    <dependency>
        <groupId>commons-beanutils</groupId>
        <artifactId>commons-beanutils</artifactId>
        <version>1.9.4</version>
    </dependency>
    
    
    <dependency>
        <groupId>commons-collections</groupId>
        <artifactId>commons-collections</artifactId>
        <version>3.2.2</version>
    </dependency>
    
    
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-lang3</artifactId>
        <version>3.4</version>
    </dependency>
    
    
    <dependency>
        <groupId>commons-lang</groupId>
        <artifactId>commons-lang</artifactId>
        <version>2.6</version>
    </dependency>
    
    
    <dependency>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
        <version>1.2</version>
    </dependency>
    
    
    <dependency>
        <groupId>commons-io</groupId>
        <artifactId>commons-io</artifactId>
        <version>2.4</version>
    </dependency>

7、使用hutool工具类

import cn.hutool.json.JSONObject;
    import cn.hutool.json.JSONUtil;

public static Object createBeanWith(Class targetClass, Object source) {
            Object target = null;
            try {
                target = targetClass.newInstance();
            } catch (Exception e) {
                return null;
            }
            JSONObject targetJson = JSONUtil.parseObj(target, false);
            JSONObject sourceJson = JSONUtil.parseObj(source, false);
            for (String key : targetJson.keySet()) {
                if (sourceJson.containsKey(key)) {
                    targetJson.set(key, sourceJson.get(key));
                }
            }
            return JSONUtil.toBean(targetJson, targetClass);
        }

8、 使用Spring类的方法：

/**
     * 这种方式是用了Spring的工具类， 不关乎是否有继承关系，
     * 只要有相同的属性就会拷贝进去
     */
    Foo foo = new Foo();
    Son son = new Son();
    BeanUtils.copyProperties(foo, son);

参考：

[父类转换成子类， 或者是类之间属性拷贝\_父类对象转换为子类对象\_孔先生在吗的博客-CSDN博客][_-CSDN]

[java_json java_json_clghxq_51CTO]: https://blog.51cto.com/u_14457/6398153
[_-CSDN]: https://blog.csdn.net/qq_37230634/article/details/108603980