基于常用json框架介绍和Jackson返回结果处理方式

json框架介绍，Jackson返回结果处理

介绍常用json框架和注解的使用，自定义返回json结构和格式

1、常用框架 阿里 fastjson,谷歌gson等

JavaBean序列化为Json，性能：Jackson > FastJson > Gson > Json-lib 同个结构

Jackson、FastJson、Gson类库各有优点，各有自己的专长

空间换时间，时间换空间

2、jackson处理相关自动

• 指定字段不返回：@JsonIgnore
• 指定日期格式：@JsonFormat(pattern="yyyy-MM-dd hh:mm:ss",locale="zh",timezone="GMT+8")
• 空字段不返回：@JsonInclude(Include.NON_NUll)
• 指定别名：@JsonProperty

实体类代码如下：

public class rData {
  
  @JsonIgnore
  private String code;
  @JsonProperty(value = "agenum")
  private int age;
  @JsonFormat(pattern="yyyy-MM-dd hh:mm:ss",locale="zh",timezone="GMT+8")
  private Date createDate;
  @JsonInclude(JsonInclude.Include.NON_NULL)
  private String name;
  public String getName() {
      return name;
  }
  public void setName(String name) {
      this.name = name;
  }
  public Date getCreateDate() {
      return createDate;
  }
  public void setCreateDate(Date createDate) {
      this.createDate = createDate;
  }
  public int getAge() {
      return age;
  }
  public void setAge(int age) {
      this.age = age;
  }
  public String getCode() {
      return code;
  }
  public void setCode(String code) {
      this.code = code;
  }
  
  public rData(String code, int age) {
      this.code = code;
      this.age = age;
  }
  public rData(String code, int age, Date createDate, String name) {
      this.code = code;
      this.age = age;
      this.createDate = createDate;
      this.name = name;
  }
}

测试类代码：

@RestController
public class HttpController {
  @GetMapping("/testjson")
  public Object param6(){
      return new rData("jackson",1,new Date(),"lion");
  }
}

结果：

{"createDate":"2018-09-18 09:36:31","name":"lion","agenum":1}

code被忽略了，所以不显示；age被别名代替"agenum"

使用jackson返回json数据

1、SpringMVC如何返回json数据

1.1、添加jar包

<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.5</version>
</dependency>

1.2、配置spring文件，添加mvc命名空间和约束等

xmlns:mvc="http://www.springframework.org/schema/mvc"
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd
<mvc:annotation-driven/>

1.3、方法上添加@ResponseBody

@ResponseBody

2、例子

2.1、配置pom.xml

<dependencies>
  <dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.11</version>
    <scope>test</scope>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.0.8.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>5.0.8.RELEASE</version>
  </dependency>
  <!-- Spring的核心工具包-->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-core</artifactId>
    <version>5.0.8.RELEASE</version>
  </dependency>
  <!--在基础IOC功能上提供扩展服务，还提供许多企业级服务的支持，有邮件服务、任务调度、远程访问、缓存以及多种视图层框架的支持-->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context</artifactId>
    <version>5.0.8.RELEASE</version>
  </dependency>
  <!-- Spring IOC的基础实现，包含访问配置文件、创建和管理bean等 -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-beans</artifactId>
    <version>5.0.8.RELEASE</version>
  </dependency>
  <!-- Spring context的扩展支持，用于MVC方面 -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-context-support</artifactId>
    <version>5.0.8.RELEASE</version>
  </dependency>
  <!-- Spring表达式语言 -->
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-expression</artifactId>
    <version>5.0.8.RELEASE</version>
  </dependency>
  <!--springAop开发必须加入的包-->
  <dependency>
    <groupId>aopalliance</groupId>
    <artifactId>aopalliance</artifactId>
    <version>1.0</version>
  </dependency>
  <dependency>
    <groupId>org.aspectj</groupId>
    <artifactId>aspectjweaver</artifactId>
    <version>1.8.13</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aspects</artifactId>
    <version>5.0.8.RELEASE</version>
  </dependency>
  <dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-aop</artifactId>
    <version>5.0.8.RELEASE</version>
  </dependency>
  <!--jackson返回json-->
  <dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.5</version>
  </dependency>
</dependencies>

2.2、配置spring.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns:p="http://www.springframework.org/schema/p"
     xmlns:context="http://www.springframework.org/schema/context"
     xmlns:mvc="http://www.springframework.org/schema/mvc"
     xsi:schemaLocation="http://www.springframework.org/schema/beans 
                         http://www.springframework.org/schema/beans/spring-beans.xsd
                          http://www.springframework.org/schema/context
                         http://www.springframework.org/schema/context/spring-context.xsd
                          http://www.springframework.org/schema/mvc
                         http://www.springframework.org/schema/mvc/spring-mvc.xsd">
  <!--扫描controller-->
  <context:component-scan base-package="com"></context:component-scan>
  <!--视图解析器-->
  <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
      <!--jsp所在位置-->
      <property name="prefix" value="/"></property>
      <!--jsp文件后缀名-->
      <property name="suffix" value=".jsp"></property>
  </bean>
  <mvc:annotation-driven /> <!--注解驱动-->
</beans>

2.3、配置web.xml

<!DOCTYPE web-app PUBLIC
"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd" >
<web-app>
<display-name>Archetype Created Web Application</display-name>
<servlet>
  <servlet-name>springMvc</servlet-name>
  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  <!--加载spring配置文件，原来是通过 ApplicationContext applicationContext = new ClassPathXmlApplicationContext("applicationContext.xml");-->
  <init-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:spring.xml</param-value>
  </init-param>
</servlet>
<servlet-mapping>
  <servlet-name>springMvc</servlet-name>
  <url-pattern>/</url-pattern>
</servlet-mapping>
<!--处理post乱码-->
<filter>
  <filter-name>characterEncodingFilter</filter-name>
  <filter-class>
    org.springframework.web.filter.CharacterEncodingFilter
  </filter-class>
  <init-param>
    <param-name>encoding</param-name>
    <param-value>utf-8</param-value>
  </init-param>
</filter>
<filter-mapping>
  <filter-name>characterEncodingFilter</filter-name>
  <url-pattern>/*</url-pattern>
</filter-mapping>
</web-app>

2.4、添加User实体类

package com.fan.entity;
import java.util.Arrays;
import java.util.Date;
public class User {
  private String username;
  private String password;
  private int[] box;
  private Date date;
  public String getUsername() {
      return username;
  }
  public void setUsername(String username) {
      this.username = username;
  }
  public String getPassword() {
      return password;
  }
  public void setPassword(String password) {
      this.password = password;
  }
  public int[] getBox() {
      return box;
  }
  public void setBox(int[] box) {
      this.box = box;
  }
  public Date getDate() {
      return date;
  }
  public void setDate(Date date) {
      this.date = date;
  }
  @Override
  public String toString() {
      return "User{" +
              "username='" + username + '\'' +
              ", password='" + password + '\'' +
              ", box=" + Arrays.toString(box) +
              ", date=" + date +
              '}';
  }
}

2.5、 TestJsonController测试类

@Controller
public class TestJsonController {
   //http://localhost:8080/testjson1
  @RequestMapping("/testjson1")
  @ResponseBody //返回json字符串注解
  public User test(){
      User user=new User();
      user.setUsername("malijuan");
      user.setPassword("123");
      user.setBox(new int[]{1,2,3});
      user.setDate(new Date());
      return user;
  }
  //http://localhost:8080/testjson2
  @RequestMapping("/testjson2")
  @ResponseBody  //返回json字符串注解
  public List test2(){
      User user=new User();
      List list=new ArrayList();
      for(int i=0;i<5;i++){
          user.setUsername("malijuan");
          user.setPassword("123");
          user.setBox(new int[]{1,2,3});
          user.setDate(new Date());
          list.add(user);
      }
      return list;
  }
}

2.6、启动tomcat测试

测试1

测试2

以上为个人经验，希望能给大家一个参考，也希望大家多多支持服务器之家。

原文链接：https://www.cnblogs.com/Mblood/p/9667191.html