java如何解析json数据

Java可使用Json库来解析JSON数据。以下是使用Jackson库来解析JSON数据的示例代码：
1. 导入Jackson库的依赖：
```xml

com.fasterxml.jackson.core
jackson-databind
2.12.4

```
2. 使用ObjectMapper类将JSON数据转换为Java对象：
```java
import com.fasterxml.jackson.databind.ObjectMapper;
public class JsonParser {
public static void main(String[] args) {
String jsonData = "{"name":"John", "age":30, "city":"New York"}";
try {
ObjectMapper objectMapper = new ObjectMapper();
Person person = objectMapper.readValue(jsonData, Person.class);
System.out.println("Name: " + person.getName());
System.out.println("Age: " + person.getAge());
System.out.println("City: " + person.getCity());
} catch (Exception e) {
e.printStackTrace();
}
}
}
class Person {
private String name;
private int age;
private String city;
// 一定要有没有参数的构造方法
public Person() {}
// getters and setters
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
}
```
以上代码将输出：
```
Name: John
Age: 30
City: New York
```
这里使用了ObjectMapper类的readValue()方法来将JSON数据转换为Person对象。Person类是一个简单的POJO类，具有与JSON数据对应的属性和相应的getter和setter方法。