依赖Jackson的json文件IO使用

依赖Jackson的json简单输出实现

1.准备工作

1.1pom.xml

<!--Jackson依赖-->
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-core</artifactId>
    <version>2.9.0</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-databind</artifactId>
    <version>2.9.0</version>
</dependency>
<dependency>
    <groupId>com.fasterxml.jackson.core</groupId>
    <artifactId>jackson-annotations</artifactId>
    <version>2.9.0</version>
</dependency>

1.2.web.xml配置

<web-app>
  <display-name>Archetype Created Web Application</display-name>
  <filter>
    <filter-name>encodingFilter</filter-name>
    <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
  </filter><!--预防乱码的filter-->
  <filter-mapping>
    <filter-name>encodingFilter</filter-name>
    <url-pattern>/</url-pattern>
  </filter-mapping>

  <servlet>
    <servlet-name>springmvc</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath*:springmvc-servlet.xml</param-value>
    </init-param>
  </servlet>
  <servlet-mapping>
    <servlet-name>springmvc</servlet-name>
    <url-pattern>/</url-pattern>
  </servlet-mapping>
</web-app>

1.3[NAME]-servlet.xml配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="
        http://www.springframework.org/schema/beans
        http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc
        http://www.springframework.org/schema/mvc/spring-mvc.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context.xsd

">

    <mvc:default-servlet-handler/>
    <mvc:annotation-driven/>
    <context:component-scan base-package="com.xxx.dao"/>
    <context:component-scan base-package="com.xxx.controller"/>

    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver" id="internalResourceViewResolver">
        <property name="suffix" value=".jsp"/>
        <property name="prefix" value="/WEB-INF/jsp/"/>
    </bean>
    
</beans>

2.新建用于测试的简单java对象（pojo)

package com.xxx.pojo;

public class User {
     String userName;
     String password;

    public User(String userName, String password) {
        this.userName = userName;
        this.password = password;
    }

    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;
    }
}

3.controller类编写

package com.xxx.controller;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.xxx.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller
public class userController {

    @RequestMapping(value="/t0",produces = "application/json;charset=UTF-8")
   //设置编码为UTF-8以免乱码
    @ResponseBody//跳过解析器，直接返回字符串
    public String test05(){
        User user=new User("张三","888444");
        ObjectMapper objectMapper=new ObjectMapper();
        String str = null;
        System.out.println("json generated");
        try {
            str = objectMapper.writeValueAsString(user);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return str;
    }
}

4.运行tomcat9，测试现象

    } catch (JsonProcessingException e) {
        e.printStackTrace();
    }
    return str;
}

}

## 4.运行tomcat9，测试现象

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