java json对象和json字符串互转的方法_将json字符串转换成对象

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包名：import net.sf.json.JSONObject;

1.maven地址

<dependency>    
		<groupId>net.sf.json-lib</groupId>    
		<artifactId>json-lib</artifactId>    
		<version>2.4</version>    
		<classifier>jdk15</classifier>    
</dependency>

2.People对象详情如下：

package pojo;
public class People {


	private int id;
	private int age;
	private String name;
	
	
	public People(int id, int age, String name) {
		super();
		this.id = id;
		this.age = age;
		this.name = name;
	}
	
	public People() {
		super();
	}


	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public int getAge() {
		return age;
	}
	public String getName() {
		return name;
	}
	public void setAge(int age) {
		this.age = age;
	}
	public void setName(String name) {
		this.name = name;
	}
	@Override
	public String toString() {
		return "People [id=" + id + ", age=" + age + ", name=" + name + "]";
	}
	
}

 3.json字符串转为JSONObject对象：

String jsonStr = "{\"name\":\"1\",\"age\":1,\"id\":0}";
// json字符串转为JSONObject 对象
JSONObject jsonObject = JSONObject.fromObject(jsonStr);
System.out.println("name:" + jsonObject.get("name"));
System.out.println("age:" + jsonObject.get("age"));
System.out.println("id:" + jsonObject.get("id"));

4.JSONObject转为json字符串：

// JSONObject转为json字符串
String string = jsonObject.toString();
System.out.println("string" + string);

5.JSONObject对象转化为javaBean对象：

// JSONObject转为javaBean
People people = (People)JSONObject.toBean(jsonObject, People.class);
System.out.println(people);

6.有时候，我们需要将一个集合json转化为一个java的List<T>集合：

例如如下的一个json字符串：

[{"age":1,"id":1,"name":"first"},
{"age":2,"id":2,"name":"second"},
{"age":3,"id":3,"name":"third"}]

这个json字符串中包含的数据可以转化为一个List<People>集合，代码如下：

// 将List的Json字符串转化为List<T>集合
		String listStr = "[{\"age\":1,\"id\":1,\"name\":\"first\"},{\"age\":2,\"id\":2,\"name\":\"second\"},{\"age\":3,\"id\":3,\"name\":\"third\"}]";
		JSONArray jsonArray2 = JSONArray.fromObject(listStr);
		List<People> peopleList2 = (List<People>)JSONArray.toCollection(jsonArray2, People.class);
		for(People peo : peopleList2)
		{
			System.out.println(peo);
		}

7.JSONArray的遍历：

List<People> peopleList = new ArrayList<People>();
		peopleList.add(new People(1,1,"first"));
		peopleList.add(new People(2,2,"second"));
		peopleList.add(new People(3,3,"third"));
		JSONArray jsonArray = JSONArray.fromObject(peopleList);
		// JSONArray的遍历
		for (int i = 0; i < jsonArray.size(); i++) {
			JSONObject jsonObject2 = jsonArray.getJSONObject(i);
			People people1 = (People)jsonObject.toBean(jsonObject2, People.class);
			System.out.println(people1);
		}