JAVA核心知识点--使用org.json.JSONObject处理Json数据

目录

引入org.json依赖

构建JSONObject

直接构建

使用Map构建

使用JavaBean构建

解析JSONObject

---

引入org.json依赖

在 maven 项目中使用 org.json ，需引入依赖：

		
		
			org.json
			json
			20160810
		

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。

 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() {
			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 map = new HashMap();
		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() {
			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 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 getFeatures() {
		return features;
	}

	public void setFeatures(Map 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() {
			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。

 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