SpringMVC中的返回值问题之一返回void

返回值为void

此方法需要引入一个json依赖

<!-- https://mvnrepository.com/artifact/com.alibaba/fastjson -->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.28</version>
</dependency>

web.xml文件

<!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>

  
  <!--编码过滤器-->
  <filter>
    <filter-name>CharactorEncoding</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>
    <init-param>
      <param-name>forceEncoding</param-name>
      <param-value>true</param-value>
    </init-param>
  </filter>
  <filter-mapping>
    <filter-name>CharactorEncoding</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

<!--配置前端控制器-->
<servlet>
  <servlet-name>springmvc</servlet-name>
  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
  <!--初始化参数-->
  <init-param>
    <param-name>contextConfigLocation</param-name>
        <param-value>classpath:springmvc06Annotion.xml</param-value>
  </init-param>

  <!--意思:Tomact启动，就将servlet创建好放入内存中了-->
  <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
  <servlet-name>springmvc</servlet-name>
  <url-pattern>/</url-pattern>
</servlet-mapping>

</web-app>

public class Student {
    private String name;
    private Integer age;

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

    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
}

@Controller
public class ThridAnnotion {
    /**
     * 返回void   json
     * @param response
     * @throws IOException
     */
    @RequestMapping("/json")
    public void Jack(HttpServletResponse response) throws IOException {
        List<Student> list=new ArrayList<Student>();
        Student student=new Student();
        student.setName("李四");
        student.setAge(20);

        Student student1=new Student();
        student1.setName("张三");
        student1.setAge(22);

        list.add(student);
        list.add(student1);

        String json = JSON.toJSONString(list);
        //将json转发到浏览器
        response.getWriter().write(json);
    }

}

springmvc06Annotion.xml文件

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       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
     ">
        <!--扫描包-->
       <context:component-scan base-package="cn.sjl.day03Annotion"></context:component-scan>
       <!--注解驱动-->
       <mvc:annotation-driven/>
</beans>

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