SpringMVC中使用@RequestBody,@ResponseBody注解实现Java对象和XML/JSON数据自动转换（下）
上一篇分析了Spring中是如何通过使用@ResponseBody注解，实现自动转换Java对象为XML,JSON数据到Reponse中。
接下来看看如果request中包含了XML或者JSON数据，反过来，如何来通过@RequestBody注解来自动转换为Java对象。
配合@RequestBody注解，以及HTTP Request Header中的Content-Type属性，HTTP Request Body中包含的XML或者JSON数据可以自动被转换成对应的Java对象。
1）首先在controller中添加handlermapping。
[java]
/**
* 根据request header中的Content-Type自动转换XML/JSON->EmployeeX对象
* 根据request header中的Accept自动选择返回XML or JSON
*/
@RequestMapping(method=RequestMethod.POST)
@ResponseBody
public EmployeeServiceResponse createEmployee(@RequestBody EmployeeX employee) {
logger.debug("creating a employee:[{}]", employee);
return new EmployeeServiceResponse(0, "");
}[java]
package learning.webapp.model;
import javax.xml.bind.annotation.XmlRootElement;
@XmlRootElement
public class EmployeeServiceResponse {
private Integer errcode;
private String errmsg;
public EmployeeServiceResponse() {
}
public EmployeeServiceResponse(Integer errcode, String errmsg) {
this.errcode = errcode;
this.errmsg = errmsg;
}
public Integer getErrcode() {
return errcode;
}
public void setErrcode(Integer errcode) {
this.errcode = errcode;
}
public String getErrmsg() {
return errmsg;
}
public void setErrmsg(String errmsg) {
this.errmsg = errmsg;
}
}2）运行以下两个测试函数
[java]
<span style="white-space:pre"> </span>@Test
public void testJsonRequestResponse() throws IOException, URISyntaxException {
String url = "http://localhost:8080/employees";
HttpHeaders requestHeaders = new HttpHeaders();
requestHeaders.set("Accept", "application/json");
requestHeaders.set("Content-Type", "application/json");
String jsonStr = "{\"name\":\"Jack\",\"salary\":16000}";
RestTemplate restTemplate = new RestTemplate();
HttpEntity<String> httpEntity = new HttpEntity<String>(jsonStr, requestHeaders);
String jsonData = restTemplate.postForObject(url, httpEntity, String.class);
System.out.println(jsonData);
}
@Test
public void testXmlRequestResponse() throws IOException, URISyntaxException {
String url = "http://localhost:8080/employees";
HttpHeaders requestHeaders = new HttpHeaders();
requestHeaders.set("Accept", "application/xml");
requestHeaders.set("Content-Type", "application/xml");
String xmlStr = "<employeeX><name>Jack</name><salary>16000</salary></employeeX>";
RestTemplate restTemplate = new RestTemplate();
HttpEntity<String> httpEntity = new HttpEntity<String>(xmlStr, requestHeaders);
String xmlData = restTemplate.postForObject(url, httpEntity, String.class);
System.out.println(xmlData);
}3）我们甚至可以任意组合请求和应答中的XML/JSON。比如Request=XML，Response=JSON
[java]
@Test
public void testXmlRequestJsonResponse() throws IOException, URISyntaxException {
String url = "http://localhost:8080/employees";
HttpHeaders requestHeaders = new HttpHeaders();
requestHeaders.set("Accept", "application/json");
requestHeaders.set("Content-Type", "application/xml");
String xmlStr = "<employeeX><name>Jack</name><salary>16000</salary></employeeX>";
RestTemplate restTemplate = new RestTemplate();
HttpEntity<String> httpEntity = new HttpEntity<String>(xmlStr, requestHeaders);
String jsonData = restTemplate.postForObject(url, httpEntity, String.class);
System.out.println(jsonData);
}类似上一篇中的分析，最关键的处理在AbstractMessageConverterMethodArgumentResolver.readWithMessageConverters(）。它会根据request header中的Content-Type属性来选择合适的message converter.
---------------------
以下引用自参考资料1：
如果不想使用<mvc:annotation-driven/>中默认的RequestMappingHandlerAdapter的话，我们可以在重新定义这个bean，spring会覆盖掉默认的RequestMappingHandlerAdapter。
为何会覆盖，请参考博客：http://www.cnblogs.com/fangjian0423/p/spring-Ordered-interface.html
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"> <property name="messageConverters"> <list> <bean class="org.springframework.http.converter.ByteArrayHttpMessageConverter"/> <bean class="org.springframework.http.converter.StringHttpMessageConverter"/> <bean class="org.springframework.http.converter.ResourceHttpMessageConverter"/> </list> </property></bean>
或者如果只想换messageConverters的话。
<mvc:annotation-driven> <mvc:message-converters> <bean class="org.example.MyHttpMessageConverter"/> <bean class="org.example.MyOtherHttpMessageConverter"/> </mvc:message-converters></mvc:annotation-driven>
转载自：http://blog.csdn.net/fw0124/article/details/48312317