未使用自定义HTTP消息转换器，未支持的媒体类型为415

问题内容：

我正在创建一个测试应用程序，以实现从XML字符串到Employee对象的转换，然后再传递给控制器。我不想使用JAXB转换器，因为目的是测试自定义HTTP消息转换器，我将在涉及用SAX解析器和一些复杂规则进行XML解析的实际用例中使用它。

以下是执行的关键步骤：

创建Employee.java类 ：域对象
创建EmployeeManagementController.java类 ：用于管理员工的Spring MVC控制器
创建EmployeeConverter.java ：用于将XML字符串转换为Employee对象的自定义转换器。
创建employee-servlet.xml ：Spring配置文件
创建web.xml ：部署描述符

Employee.java

@Component
@XmlRootElement(name="employee")
@XmlAccessorType(XmlAccessType.FIELD)
public class Employee{

@XmlElement(name="name")
String name;
@XmlElement(name="designation")
String designation;
@XmlElement(name="skill")
String skill;

public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDesignation() {
return designation;
}
public void setDesignation(String designation) {
this.designation = designation;
}
public String getSkill() {
return skill;
}
public void setSkill(String skill) {
this.skill = skill;
}

}

EmployeeManagementController.java

@Controller
@RequestMapping(value="/emp")
public class EmployeeManagementController {

    @RequestMapping(value="/add/employee", method=RequestMethod.POST, consumes="text/html")
    public void addEmployee(@RequestBody Employee employee){
        System.out.println("Employee Name : "+employee.getName());
        System.out.println("Employee Designation : "+employee.getDesignation());
        System.out.println("Employee Skill : "+employee.getSkill());

    }


}

EmployeeConverter.java

@Component
public class EmployeeConverter extends AbstractHttpMessageConverter<Employee>{

    @Override
    protected Employee readInternal(Class<? extends Employee> arg, HttpInputMessage inputMsg) throws IOException,
            HttpMessageNotReadableException {
        // TODO Auto-generated method stub
        Map<String,String> paramMap = getPostParameter(inputMsg);
        BufferedReader file =  new BufferedReader(new StringReader(paramMap.get("xml")));
        Employee employee = null;
        JAXBContext jaxbContext;
        try {
            jaxbContext = JAXBContext.newInstance(Employee.class);
            Unmarshaller jaxbUnmarshaller = jaxbContext.createUnmarshaller();
            employee = (Employee) jaxbUnmarshaller.unmarshal(file);
        } catch (JAXBException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        System.out.println(employee);
        return employee;
    }

    @Override
    protected boolean supports(Class<?> type) {
        if(type.getSimpleName().equalsIgnoreCase("Employee")){
            return true;
        }
        return false;
    }

    @Override
    protected void writeInternal(Employee arg0, HttpOutputMessage arg1)
            throws IOException, HttpMessageNotWritableException {
        // TODO Auto-generated method stub

    }

    private Map<String,String> getPostParameter(HttpInputMessage input) throws IOException{
        String payload = null;
        String[] params = null;
        BufferedReader buf = new BufferedReader(new InputStreamReader(input.getBody()));
        Map<String,String> paramMap = new HashMap<String,String>();

        String line="";
        while((line = buf.readLine())!=null){
            payload = payload+line;
        }

        if(payload.contains("&")){
            params = payload.split("&");
            for(String param : params){
                paramMap.put(param.split("=")[0],param.split("=")[1]);
            }
        }

        return paramMap;
    }


}

员工servlet.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:context="http://www.springframework.org/schema/context"
                xmlns:mvc="http://www.springframework.org/schema/mvc"
                xmlns:util="http://www.springframework.org/schema/util"
                xsi:schemaLocation="http://www.springframework.org/schema/beans 
                http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
                http://www.springframework.org/schema/context 
                http://www.springframework.org/schema/context/spring-context-3.1.xsd
                http://www.springframework.org/schema/mvc
                http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd
                http://www.springframework.org/schema/util
                http://www.springframework.org/schema/util/spring-util-3.1.xsd">

         <mvc:default-servlet-handler/>

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

         <mvc:annotation-driven>
            <mvc:message-converters>
                <bean class="com.converter.EmployeeConverter"/>             
            </mvc:message-converters>
        </mvc:annotation-driven>

        <bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
            <property name="mediaTypes">
                <map>
                    <entry key="json" value="application/json"/>
                    <entry key="xml" value="text/xml"/>
                    <entry key="htm" value="text/html"/>
                </map>
            </property>
            <property name="defaultContentType" value="text/html"/>
        </bean>

        <!-- <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter">
            <property name="messageConverters">    
                <util:list id="beanList">
                    <ref bean="employeeConverter"/>       
                </util:list>
            </property>
        </bean>  -->

        <!-- <bean id="employeeConverter" class="com.converter.EmployeeConverter"/> -->



</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" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>TestConverter</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>    
  </welcome-file-list>

  <servlet>
    <servlet-name>employee</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
  <servlet-name>employee</servlet-name>
  <url-pattern>/*</url-pattern>
  </servlet-mapping>

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>/WEB-INF/employee-servlet.xml</param-value>
</context-param>

<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

</web-app>

当我使用FireFox RestClient时，得到的响应为： 415 Unsupproted Media Type。

我在RestClient中将Content-Type和Accept标头设置为text / xml，并将主体中的以下XML字符串作为参数传递：

xml=<employee><name>Jack</name><designation>Account Director</designation><skill>Commuication</skill></employee>

有人可以帮忙让我知道需要进行哪些更改吗？我也尝试过AnnotationMethodHandlerAdapter用于注册消息转换器。

问题答案：

1.设置媒体类型

将您的实现与HttpMessageConverterSpring提供的某些实现进行比较（例如“
MappingJackson2HttpMessageConverter”），表明您错过了定义的过程supportedMediaTypes。

HttpMessageConverter扩展的常用方法AbstractHttpMessageConverter<T>是通过使用super构造函数在构造函数中设置媒体类型AbstractHttpMessageConverter.(MediaType supportedMediaType)。

 public class EmployeeConverter extends AbstractHttpMessageConverter<Employee> {
      public EmployeeConverter() {
            super(new MediaType("text", "xml", Charset.forName("UTF-8")));
      }
 }

顺便说一句：您还可以注册不止一种媒体类型**

super(MediaType.APPLICATION_XML,
      MediaType.TEXT_XML,
      new MediaType("application", "*+xml"));

顺便说一句2：对于xml转换者，应该考虑从 AbstractXmlHttpMessageConverter<T>

2.注册您的转换器

<mvc:annotation-driven>
    <mvc:message-converters>
       ...
       <bean class="com.example.YourConverter"/>
    </mvc:message-converters>
</mvc:annotation-driven>

~~的主要缺点<mvc:message- converters>是，它将替换默认配置，因此您还必须注册所有默认HttpMessageConverter显式。~~

要保留默认消息转换，您需要使用： <mvc:message-converters register-defaults="true">...

*由其他实现（例如MappingJackson2HttpMessageConverter´）使用
**示例取自AbstractXmlHttpMessageConverter<T>

未使用自定义HTTP消息转换器，未支持的媒体类型为415

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