org.json.JSONObject & org.json.J

引入org.json依赖

在 maven 项目中使用 org.json ，需引入依赖：

        <!-- 引入org.json所需依赖 -->
        <dependency>
            <groupId>org.json</groupId>
            <artifactId>json</artifactId>
            <version>20160810</version>
        </dependency>

构建JSONObject

直接构建

可以直接使用 new 关键字实例化一个JSONObject对象，然后调用它的 put() 方法对其字段值进行设置。

image.png

范例：

        JSONObject jsonObj = new JSONObject();
        jsonObj.put("female", true);
        jsonObj.put("hobbies", Arrays.asList(new String[] { "yoga", "swimming" }));
        jsonObj.put("discount", 9.5);
        jsonObj.put("age", "26");
        jsonObj.put("features", new HashMap<String, Integer>() {
            private static final long serialVersionUID = 1L;
            {
                put("height", 175);
                put("weight", 70);
            }
        });
        System.out.println(jsonObj);

结果：

{
    "features": {
        "weight": 70,
        "height": 175
    },
    "hobbies": ["yoga", "swimming"],
    "discount": 9.5,
    "female": true,
    "age": 26
}

使用Map构建

范例：

        Map<String, Object> map = new HashMap<String, Object>();
        map.put("female", true);
        map.put("hobbies", Arrays.asList(new String[] { "yoga", "swimming" }));
        map.put("discount", 9.5);
        map.put("age", "26");
        map.put("features", new HashMap<String, Integer>() {
            private static final long serialVersionUID = 1L;
            {
                put("height", 175);
                put("weight", 70);
            }
        });
        JSONObject jsonObj = new JSONObject(map);
        System.out.println(jsonObj);

程序执行结果与上例相同。

使用JavaBean构建

范例：

import java.util.Map;
 
public class UserInfo {
 
    private Boolean female;
    private String[] hobbies;
    private Double discount;
    private Integer age;
    private Map<String, Integer> features;
 
    public Boolean getFemale() {
        return female;
    }
 
    public void setFemale(Boolean female) {
        this.female = female;
    }
 
    public String[] getHobbies() {
        return hobbies;
    }
 
    public void setHobbies(String[] hobbies) {
        this.hobbies = hobbies;
    }
 
    public Double getDiscount() {
        return discount;
    }
 
    public void setDiscount(Double discount) {
        this.discount = discount;
    }
 
    public Integer getAge() {
        return age;
    }
 
    public void setAge(Integer age) {
        this.age = age;
    }
 
    public Map<String, Integer> getFeatures() {
        return features;
    }
 
    public void setFeatures(Map<String, Integer> features) {
        this.features = features;
    }
 
}

        UserInfo userInfo = new UserInfo();
        userInfo.setFemale(true);
        userInfo.setHobbies(new String[] { "yoga", "swimming" });
        userInfo.setDiscount(9.5);
        userInfo.setAge(26);
        userInfo.setFeatures(new HashMap<String, Integer>() {
            private static final long serialVersionUID = 1L;
            {
                put("height", 175);
                put("weight", 70);
            }
        });
        JSONObject jsonObj = new JSONObject(userInfo);
        System.out.println(jsonObj);

程序执行结果与上例相同。

解析JSONObject

JSONObject为每一种数据类型都提供了一个getXXX(key)方法，例如：获取字符串类型的字段值就使用getString()方法，获取数组类型的字段值就使用getJSONArray()方法。

image.png

范例：

        // 获取基本类型数据
        System.out.println("Female: " + jsonObj.getBoolean("female"));
        System.out.println("Discount: " + jsonObj.getDouble("discount"));
        System.out.println("Age: " + jsonObj.getLong("age"));
        
        // 获取JSONObject类型数据
        JSONObject features = jsonObj.getJSONObject("features");
        String[] names = JSONObject.getNames(features);
        System.out.println("Features: ");
        for (int i = 0; i < names.length; i++) {
            System.out.println("\t"+features.get(names[i]));
        }
 
        // 获取数组类型数据
        JSONArray hobbies = jsonObj.getJSONArray("hobbies");
        System.out.println("Hobbies: ");
        for (int i = 0; i < hobbies.length(); i++) {
            System.out.println("\t"+hobbies.get(i));
        }

结果：

Female: true
Discount: 9.5
Age: 26
Features: 
    70
    175
Hobbies: 
    yoga
    swimming

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原文链接：https://blog.csdn.net/pengjunlee/article/details/83985602