如何使用 Java JSON Parser 解析复杂 JSON

要使用Java JSON Parser解析复杂JSON，您需要首先了解JSON结构并选择合适的JSON库

1. 添加Gson依赖项

在您的项目中，首先需要添加Gson库的依赖项。如果您使用Maven，请将以下代码添加到pom.xml文件中：

<dependencies>
  <dependency>
    <groupId>com.google.code.gson</groupId>
    <artifactId>gson</artifactId>
    <version>2.8.9</version>
  </dependency>
</dependencies>

如果您使用Gradle，请将以下代码添加到build.gradle文件中：

dependencies {
    implementation 'com.google.code.gson:gson:2.8.9'
}

2. 创建Java类以映射JSON对象

为了解析复杂JSON，您需要创建与JSON结构相对应的Java类。例如，假设我们有以下复杂JSON：

{
  "name": "John",
  "age": 30,
  "address": {
    "street": "123 Main St",
    "city": "New York",
    "state": "NY",
    "zipCode": "10001"
  },
  "phoneNumbers": [
    {
      "type": "home",
      "number": "555-555-1234"
    },
    {
      "type": "work",
      "number": "555-555-5678"
    }
  ]
}

为这个JSON创建对应的Java类：

public class Person {
    private String name;
    private int age;
    private Address address;
    private List<PhoneNumber> phoneNumbers;

    // Getters and Setters
}

public class Address {
    private String street;
    private String city;
    private String state;
    private String zipCode;

    // Getters and Setters
}

public class PhoneNumber {
    private String type;
    private String number;

    // Getters and Setters
}

3. 使用Gson解析JSON字符串

现在您可以使用Gson库将JSON字符串解析为Java对象：

import com.google.gson.Gson;

public class Main {
    public static void main(String[] args) {
        String json = "{\"name\":\"John\",\"age\":30,\"address\":{\"street\":\"123 Main St\",\"city\":\"New York\",\"state\":\"NY\",\"zipCode\":\"10001\"},\"phoneNumbers\":[{\"type\":\"home\",\"number\":\"555-555-1234\"},{\"type\":\"work\",\"number\":\"555-555-5678\"}]}";

        Gson gson = new Gson();
        Person person = gson.fromJson(json, Person.class);

        System.out.println("Name: " + person.getName());
        System.out.println("Age: " + person.getAge());
        System.out.println("Street: " + person.getAddress().getStreet());
        System.out.println("City: " + person.getAddress().getCity());
        System.out.println("State: " + person.getAddress().getState());
        System.out.println("Zip Code: " + person.getAddress().getZipCode());
        System.out.println("Home Phone: " + person.getPhoneNumbers().get(0).getType() + ": " + person.getPhoneNumbers().get(0).getNumber());
        System.out.println("Work Phone: " + person.getPhoneNumbers().get(1).getType() + ": " + person.getPhoneNumbers().get(1).getNumber());
    }
}

这将输出：

Name: John
Age: 30
Street: 123 Main St
City: New York
State: NY
Zip Code: 10001
Home Phone: home: 555-555-1234
Work Phone: work: 555-555-5678

这就是如何使用Java JSON Parser（Gson库）解析复杂JSON的方法。您可以根据需要调整代码以适应您的具体需求。