接受/返回XML/JSON请求和响应 - Spring MVC

Question

我需要编写一个休息服务,它接受XML/JSON作为输入(POST方法)和XML/JSON作为输出(基于输入格式).我尝试过以下方法来实现这一点,但没有帮助.Endpoint方法同时接受XML/JSON但在响应时它总是根据@RequestMapping -produces中指定的顺序提供JSON或XML.任何帮助都将非常感谢.

我的端点方法:

@RequestMapping(value = "/getxmljson", method = RequestMethod.POST,produces={"application/json","application/xml"},
        consumes={"application/json", "application/xml"})
public @ResponseBody Student processXMLJsonRequest(@RequestBody Student student)
        throws Exception {
    System.out.println("*************Inside Controller");
    return student;
}

POJO课程:Student.java

import java.io.Serializable;
import java.util.ArrayList;

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;

import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@XmlRootElement(name = "student")
@XmlType(propOrder = {"id", "name", "graduationTime", "courses"})
@JsonPropertyOrder({"id", "name", "graduationTime", "courses"})
public class Student implements Serializable {
    private static final long serialVersionUID = 1L;

    private int id;
    private String name;
    private String graduationTime;
    private ArrayList<Course> courses = new ArrayList<Course>();

    @XmlElement
    public int getId() { return id; }
    @XmlElement
    public String getName() { return name; }
    @XmlElement
    public String getGraduationTime() { return graduationTime; }
    @XmlElement
    public ArrayList<Course> getCourses() { return courses; }

    public void setId(int value) { this.id = value; }
    public void setName(String value) { this.name = value; }
    public void setGraduationTime(String value) { this.graduationTime = value; }
    public void setCourses(ArrayList<Course> value) { this.courses = value; }

    @JsonIgnore
    public String toString() {
        return this.name + " - "
                + graduationTime == null? "Unknown" : graduationTime.toString();
    }

    public Student() {}
    public Student(int id, String name, String graduationTime) {
        this.id = id;
        this.name = name;
        this.graduationTime = graduationTime;
    }
}

POJO课程:Course.java

import java.io.Serializable;

import javax.xml.bind.annotation.XmlElement;
import javax.xml.bind.annotation.XmlRootElement;
import javax.xml.bind.annotation.XmlType;

import com.fasterxml.jackson.annotation.JsonPropertyOrder;

@XmlRootElement(name = "course")
@XmlType(propOrder = {"courseName", "score"})
@JsonPropertyOrder({"courseName", "score"})
public class Course implements Serializable {
    private static final long serialVersionUID = 1L;

    private String courseName;
    private Integer score;

    public @XmlElement String getCourseName() { return courseName; }
    public @XmlElement Integer getScore() { return score; }

    public void setCourseName(String value) { courseName = value; }
    public void setScore(Integer value) { score = value; }

    public Course() {}
    public Course(String courseName, Integer score) {
        this.courseName = courseName;
        this.score = score;
    }
}

春天-config.xml中

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/mvc"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:sws="http://www.springframework.org/schema/web-services"
    xmlns:jee="http://www.springframework.org/schema/jee" xmlns:oxm="http://www.springframework.org/schema/oxm"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
            http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
            http://www.springframework.org/schema/web-services
        http://www.springframework.org/schema/web-services/web-services-2.0.xsd
            http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
            http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-4.0.xsd
       http://www.springframework.org/schema/oxm http://www.springframework.org/schema/oxm/spring-oxm-4.0.xsd
       http://www.springframework.org/schema/util
            http://www.springframework.org/schema/util/spring-util-2.5.xsd">

    <!-- DispatcherServlet Context: defines this servlet's request-processing 
        infrastructure -->

    <!-- Enables the Spring MVC @Controller programming model -->
    <annotation-driven />

    <!-- Handles HTTP GET requests for /resources/** by efficiently serving 
        up static resources in the ${webappRoot}/resources directory -->
    <resources mapping="/resources/**" location="/resources/" />

    <!-- Configure to plugin JSON as request and response in method handler -->
    <beans:bean
        class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
        <beans:property name="messageConverters">
            <beans:list>
                <beans:ref bean="jsonMessageConverter" />
                <beans:ref bean="xmlMessageConverter" />
            </beans:list>
        </beans:property>
    </beans:bean>

    <!-- Configure bean to convert JSON to POJO and vice versa -->
    <beans:bean id="jsonMessageConverter"
        class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
    </beans:bean>

    <beans:bean id="xmlMessageConverter"
        class="org.springframework.http.converter.xml.Jaxb2RootElementHttpMessageConverter">
    </beans:bean>

    <beans:bean id="restTemplate" class="org.springframework.web.client.RestTemplate">

    </beans:bean>

    <beans:bean id="objectMapper" class="com.fasterxml.jackson.databind.ObjectMapper" />
    <context:component-scan base-package="com.test" />

</beans:beans>

Json输入:

{
"id":2014,
"name":"test",
"graduationtime":"09/05/2014",
"courses":[
{
"courseName":"Math",
"score":150
},
{
"courseName":"Che",
"score":150
}
]
}

XML输入:

<?xml version="1.0" encoding="UTF-8" ?>
<student>
<id>2014</id>
<name>test</name>
<graduationTime>09/05/2014</graduationTime>
<courses>
    <courseName>Math</courseName>
    <score>150</score>
</courses>
<courses>
    <courseName>Che</courseName>
    <score>150</score>
</courses>
</student>

Answer 1

使用相同控制器处理不同数据格式的最佳实践是让框架完成计算编组和解组机制的所有工作.

第1步:使用最少的控制器配置

@RequestMapping(value = "/getxmljson", method = RequestMethod.POST)
@ResponseBody
public Student processXMLJsonRequest(@RequestBody Student student) {
  return student;
}

没有必要指定consumes和produces这里.例如,考虑您可能希望将来使用相同的方法处理其他格式,例如Google Protocol Buffers,EDI等.保持控制器免受攻击,consumes并produces允许您通过全局配置添加数据格式,而不必修改控制器代码.

第2步:使用ContentNegotiatingViewResolver而不是RequestMappingHandlerAdapter

  <bean class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
    <property name="defaultViews">
      <list>
        <bean class="org.springframework.web.servlet.view.json.MappingJackson2JsonView"/>
      </list>
    </property>
  </bean>

让视图解析器决定如何读取传入数据以及如何将其写回.

第3步:使用Accepts和Content-TypeHTTP标头

使用正确的HTTP标头值命中控制器将强制ContentNegotiatingViewResolver使用适当的数据表示自动编组和解组数据.

如果要以JSON格式交换数据,请将两个标头都设置为application/json.如果您想要XML,请将两者都设置为application/xml.

如果您不想使用HTTP标头(理想情况下应该这样),您只需添加.json或添加.xmlURL即可ContentNegotiatingViewResolver.

您可以查看我使用您的代码片段创建的示例应用程序,该代码片段适用于JSON和XML.

Answer 2

除了Manish上面的答案,如果你不想使用基于xml的配置,请使用这个基于java的配置代替 -

@Bean
public ViewResolver contentNegotiatingViewResolver() {
    ContentNegotiatingViewResolver resolver =
            new ContentNegotiatingViewResolver();

    List<View> views = new ArrayList<>();
    views.add(new MappingJackson2XmlView());
    views.add(new MappingJackson2JsonView());

    resolver.setDefaultViews(views);
    return resolver;
}

Answer 3

注册一个过滤器来拦截每个请求，将其转换HttpServletRequest为一个实现HttpServletRequestWrapper并返回headerContent-Type的值Accept。例如，您可以注册一个名为SameInSameOutFilter如下的过滤器：

@Component
public class SameInSameOutFilter extends GenericFilterBean {
    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        SameInSameOutRequest wrappedRequest = new SameInSameOutRequest((HttpServletRequest) request);
        chain.doFilter(wrappedRequest, response);
    }
}

它将当前请求包装在SameInSameOutRequest：

public class SameInSameOutRequest extends HttpServletRequestWrapper {
    public SameInSameOutRequest(HttpServletRequest request) {
        super(request);
    }

    @Override
    public String getHeader(String name) {
        if (name.equalsIgnoreCase("accept")) {
            return getContentType();
        }

        return super.getHeader(name);
    }
}

HttpMessageConverter这个包装器告诉 spring mvc根据请求的值选择一个Content-Type。如果请求正文Content-Type是application/xml，则响应将为XML。否则，响应将为JSON。

另一个解决方案是在每个请求中手动设置Accept标头Content-Type并避免所有这些黑客行为。