JSON对象转换为JAVA对象

我们在做项目的时候通常会遇到JSON字符串，我们所需要的数据就在这JSON字符串中，所以我们需要把JSON字符串中的数据拿出来，接下来我将告诉大家如何操作。

{
    "country": "中国",
    "province": [{
            "city": "西安",
            "postoffice": 710126,
            "school": {
                "name": "西安电子科技大学",
                "major": "computer"
            },
            "capital": "true"
        },
        {
            "city": "北京",
            "postoffice": 826123,
            "school": {
                "name": "北京大学",
                "major": "fiance"
            },
            "capital": "true"
        },
        {
            "city": "温州市",
            "postoffice": 236556,
            "school": {
                "name": "浙江大学",
                "major": "accounting"
            },
            "capital": "false"
        }
    ]
}

首先查看我么接收到的JSON字符串在JSON校验器上检验查看JSON是否合法，如果校验器显示为正确的JSON这时候我们开始进行对象转换工作。

image.png

接着我们在我们项目的pom文件中中加入相关的依赖。

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

然后对照JSON的形式编写对应的java类（一般{} 对应的java类，[]对应的数组, ：对应java类中的属性）

public class InternationalSchool implements Serializable{
    private String country;
    private List<Province> province;

    public String getCountry() {
        return country;
    }

    public void setCountry(String country) {
        this.country = country;
    }

    public List<Province> getProvince() {
        return province;
    }

    public void setProvince(List<Province> province) {
        this.province = province;
    }

    @Override
    public String toString() {
        return "InternationalSchool{" +
                "country='" + country + '\'' +
                ", province=" + province +
                '}';
    }
}

public class Province implements Serializable{ {
    private String city;
    private String postoffice;
    private List<School> school;
    private boolean capital;

    public String getCity() {
        return city;
    }

    public void setCity(String city) {
        this.city = city;
    }

    public String getPostoffice() {
        return postoffice;
    }

    public void setPostoffice(String postoffice) {
        this.postoffice = postoffice;
    }

    public List<School> getSchool() {
        return school;
    }

    public void setSchool(List<School> school) {
        this.school = school;
    }

    public boolean isCapital() {
        return capital;
    }

    public void setCapital(boolean capital) {
        this.capital = capital;
    }

    @Override
    public String toString() {
        return "Province{" +
                "city='" + city + '\'' +
                ", postoffice='" + postoffice + '\'' +
                ", school=" + school +
                ", capital=" + capital +
                '}';
    }
}

public class School implements Serializable{ {
    private String name;
    private String major;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getMajor() {
        return major;
    }

    public void setMajor(String major) {
        this.major = major;
    }

    @Override
    public String toString() {
        return "School{" +
                "name='" + name + '\'' +
                ", major='" + major + '\'' +
                '}';
    }
}

接着我们编写测试类进行测试。

import net.sf.json.JSONObject;
import java.util.List;

public class Demo {
    public static void main(String[] args) {
        String jsonData = "{\n" +
                "\t\"country\": \"中国\",\n" +
                "\t\"province\": [{\n" +
                "\t\t\t\"city\": \"西安\",\n" +
                "\t\t\t\"postoffice\": 710126,\n" +
                "\t\t\t\"school\": {\n" +
                "\t\t\t\t\"name\": \"西安电子科技大学\",\n" +
                "\t\t\t\t\"major\": \"computer\"\n" +
                "\t\t\t},\n" +
                "\t\t\t\"capital\": \"true\"\n" +
                "\t\t},\n" +
                "\t\t{\n" +
                "\t\t\t\"city\": \"北京\",\n" +
                "\t\t\t\"postoffice\": 826123,\n" +
                "\t\t\t\"school\": {\n" +
                "\t\t\t\t\"name\": \"北京大学\",\n" +
                "\t\t\t\t\"major\": \"fiance\"\n" +
                "\t\t\t},\n" +
                "\t\t\t\"capital\": \"true\"\n" +
                "\t\t},\n" +
                "\t\t{\n" +
                "\t\t\t\"city\": \"温州市\",\n" +
                "\t\t\t\"postoffice\": 236556,\n" +
                "\t\t\t\"school\": {\n" +
                "\t\t\t\t\"name\": \"浙江大学\",\n" +
                "\t\t\t\t\"major\": \"accounting\"\n" +
                "\t\t\t},\n" +
                "\t\t\t\"capital\": \"false\"\n" +
                "\t\t}\n" +
                "\t]\n" +
                "}";

        JSONObject jsonObject= JSONObject.fromObject(jsonData);
        InternationalSchool inSchool = (InternationalSchool) JSONObject.toBean(jsonObject,InternationalSchool.class);
        System.out.println(inSchool);
        String country = inSchool.getCountry();
        List<Province> provinces = inSchool.getProvince();
        System.out.println("打印provinces的到的是provinces中的结果");
    }
}

最后查看运行结果

image.png

总结：JSON对象和JAVA对象转换常见的情况。
JSON 对象装换为JAVA对象

JSONObject jsonObject= JSONObject.fromObject(jsonData);
 InternationalSchool inSchool = (InternationalSchool) JSONObject.toBean(jsonObject,InternationalSchool.class);

JAVA对象转换为JSON对象

School school = new School();
school.setMajor("computer");
school.setName("西安电子科技大学");
JSONObject jsonData = JSONObject.fromObject(school);
System.out.println(jsonData);

JSONArray对象转为JAVA对象

JSONArray array = JSONArray.fromObject("province ");
 List<Person> list = JSONArray.toList(array, Person.class);