如何在 Spring MVC 中解决 HTTP 状态 406

Question

我是初学者并尝试使用 spring MVC 创建 REST api，但我收到 HTTP 406 错误。我不知道代码出了什么问题。这是我的控制器。

RestController.Java

 package com.nitish.sample;
    @RestController
    public class LoginRESTController {

    @Autowired
    public LoginService loginService;

    @ResponseBody
    @RequestMapping(value = "/api/login",method = RequestMethod.GET,headers="Accept=*/*",produces = {MediaType.APPLICATION_JSON_VALUE}) 
    public List<Login> authentication(){        
        List<Login> login = loginService.getUser();     
        return login;
    }}

pom.xml

<dependencies>
<dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-databind</artifactId>
        <version>2.9.8</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-core</artifactId>
        <version>2.9.8</version>
    </dependency>
    <dependency>
        <groupId>com.fasterxml.jackson.core</groupId>
        <artifactId>jackson-annotations</artifactId>
        <version>2.9.8</version>
    </dependency>
    <dependency>
        <groupId>org.codehaus.jackson</groupId>
        <artifactId>jackson-core-asl</artifactId>
        <version>1.9.13</version>
    </dependency>
    <dependency>
        <groupId>org.codehaus.jackson</groupId>
        <artifactId>jackson-mapper-asl</artifactId>
        <version>1.9.13</version>
    </dependency>
</dependencies>

为了更清楚，我添加了 dispachet servlet 和 web.xml HelloWebSpring-servlet.xml

 <beans xmlns = "http://www.springframework.org/schema/beans"
   xmlns:context = "http://www.springframework.org/schema/context"
   xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
   xmlns:mvc="http://www.springframework.org/schema/mvc"
   xsi:schemaLocation = "http://www.springframework.org/schema/beans     
   http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
   http://www.springframework.org/schema/context 
   http://www.springframework.org/schema/context/spring-context-3.0.xsd">

   <context:component-scan base-package = "com.nitish.sample" />   

   <bean class = "org.springframework.web.servlet.view.InternalResourceViewResolver">
    <!-- <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/> -->
      <property name = "prefix" value = "/WEB-INF/jsp/" />
      <property name = "suffix" value = ".jsp" />
   </bean>


</beans>

web.xml

 <?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>HelloWebSpring</display-name>

  <servlet>
      <servlet-name>HelloWebSpring</servlet-name>
      <servlet-class>
         org.springframework.web.servlet.DispatcherServlet
      </servlet-class>
      <load-on-startup>1</load-on-startup>
   </servlet>

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

</web-app>

这是服务器快照

Answer 1

实际上，您应该尝试将其包装到 ResponseEntity 中。我会这样做：

@RequestMapping(value = "/api/login",method = RequestMethod.GET) 
public ResponseEntity<?> authentication(){        
    List<Login> login = loginService.getUser();     
    return new ResponseEntity<>(login, HttpStatus.OK);
}}

我认为这应该可行。

Answer 2

以下是我想尝试的可能解决方案：

1. 由于您使用的是@RestController，因此它在内部提供了@ResponseBody，因此您不必使用它，因此请删除@ResponseBody 注释。

2. 尝试删除接受和生成属性，因为其余控制器内容类型是 JSON 本身。

3. 此外，如果您使用邮递员或任何其他客户端发出请求，请确保在标头中添加内容类型。

希望对您有所帮助..！

Answer 3

1. 删除标题=“Accept=/”。
2. 在您的 HelloWebSpring-Servlet.xml 添加 mvc:annotation-driven 。

这将使 spring 配置你的@RestController。

<beans xmlns = "http://www.springframework.org/schema/beans"
   xmlns:context = "http://www.springframework.org/schema/context"
   xmlns:xsi = "http://www.w3.org/2001/XMLSchema-instance"
   xmlns:mvc="http://www.springframework.org/schema/mvc"
   xsi:schemaLocation = "http://www.springframework.org/schema/beans     
   http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
   http://www.springframework.org/schema/context 
   http://www.springframework.org/schema/context/spring-context-3.0.xsd">

   <mvc:annotation-driven /> 
   <context:component-scan base-package = "com.nitish.sample" />   

   <bean class = "org.springframework.web.servlet.view.InternalResourceViewResolver">
    <!-- <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/> -->
      <property name = "prefix" value = "/WEB-INF/jsp/" />
      <property name = "suffix" value = ".jsp" />
   </bean>


</beans>

mvc:annotation-driven 详情：https://docs.spring.io/spring/docs/3.0.x/spring-framework-reference/html/mvc.html#mvc-config