您当前的位置： 首页 > 慢生活 > 程序人生 网站首页程序人生

11_JSON_解析器Jackson_java对象转json

发布时间：2022-09-30 18:10:22编辑：雪饮阅读（）

处理maven依赖：

* 所需要的类ObjectMapper

* 关键字：jackson-databind

* File=>Project Structure...=>Project Settings=>Libraries=>+=>From Maven...=>搜索jackson-databind并勾选Download to

* 将下载下来的那个lib目录复制到web/WEB-INF下面，其它的就正常ok、apply。

建立待转换的类Company（并创建好getter和setter以及constructor(用过安卓Gjson的经验直觉)）:

package package3.servlet;

import java.util.ArrayList;

public class Company {
    private String company_name;
    private double salary;
    private ArrayList<Person> persons;
    private Person legalPerson;

    public Company(String company_name, double salary, ArrayList<Person> persons, Person legalPerson) {
        this.company_name = company_name;
        this.salary = salary;
        this.persons = persons;
        this.legalPerson = legalPerson;
    }

    public String getCompany_name() {
        return company_name;
    }

    public void setCompany_name(String company_name) {
        this.company_name = company_name;
    }

    public double getSalary() {
        return salary;
    }

    public void setSalary(double salary) {
        this.salary = salary;
    }

    public ArrayList<Person> getPersons() {
        return persons;
    }

    public void setPersons(ArrayList<Person> persons) {
        this.persons = persons;
    }

    public Person getLegalPerson() {
        return legalPerson;
    }

    public void setLegalPerson(Person legalPerson) {
        this.legalPerson = legalPerson;
    }
}

Company依赖类Person：

package package3.servlet;
 
 public class Person {
     private String name;
     private int age;
 
     public Person(String name, int age) {
         this.name = name;
         this.age = age;
     }
 
     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;
     }
 }

objectMapper.writeValueAsString一键转换java对象到json字符串

package package3.servlet;
 
 import com.fasterxml.jackson.databind.ObjectMapper;
 
 import javax.servlet.ServletException;
 import javax.servlet.annotation.WebServlet;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
 import java.util.ArrayList;
 /*
 *
 * 所需要的类ObjectMapper
 * 关键字：jackson-databind
 * File=>Project Structure...=>Project Settings=>Libraries=>+=>From Maven...=>搜索jackson-databind并勾选Download to
 * 将下载下来的那个lib目录复制到web/WEB-INF下面，其它的就正常ok、apply
 *
 *
 * */
 @WebServlet("/ServletTest")
 public class ServletTest extends HttpServlet {
     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         /*
         * 可能会抛出异常：
         * javax.servlet.ServletException: Servlet执行抛出一个异常
    org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
    *可能的原因：下载后的lib目录没有放在web/WEB-INF下面
         *
         * */
        ObjectMapper objectMapper = new ObjectMapper();
         ArrayList<Person> persons=new ArrayList<Person>();
         Person legalPerson=new Person("布鲁斯韦恩",28);
         persons.add(new Person("雪饮",24));
         persons.add(legalPerson);
         Company compay=new Company("韦恩企业",130000.00,persons,legalPerson);
         String jsonString = objectMapper.writeValueAsString(compay);
         response.setContentType("text/html;charset=utf-8");
         response.getWriter().write(jsonString);
     }
 
     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         this.doPost(request, response);
     }
 }