SpringMVC中使用@RequestBody,@ResponseBody注解實作Java對象和XML/JSON資料自動轉換（下）...

        上一篇分析了Spring中是如何通過使用@ResponseBody注解，實作自動轉換Java對象為XML,JSON資料到Reponse中。

        接下來看看如果request中包含了XML或者JSON資料，反過來，如何來通過@RequestBody注解來自動轉換為Java對象。

        配合@RequestBody注解，以及HTTP Request Header中的Content-Type屬性，HTTP Request Body中包含的XML或者JSON資料可以自動被轉換成對應的Java對象。

1).首先在controller中添加handlermapping

/**
 * 根據request header中的Content-Type自動轉換XML/JSON->UserDTOX對象
 * 根據request header中的Accept自動選擇傳回XML or JSON
 */
@ResponseBody
@RequestMapping(value="/createUser", method = RequestMethod.POST)
public UserDTOX createUser(@RequestBody UserDTOX userDTOX) {
	logger.debug("creating a UserDTO:[{}]", userDTOX);
	return new UserDTOX("Hi " + userDTOX.getName(), userDTOX.getAge() + 1);
}
           

2).運作以下兩個測試函數

@Test
public void testJsonRequestResponse() throws IOException, URISyntaxException {
	
	String url = "http://localhost:8080/SpringMVC/createUser";
	HttpHeaders requestHeaders = new HttpHeaders();
	requestHeaders.set("Accept", "application/json");
	requestHeaders.set("Content-Type", "application/json");

	String jsonStr = "{\"name\":\"Jack\",\"age\":16}";

	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/SpringMVC/createUser";
	HttpHeaders requestHeaders = new HttpHeaders();
	requestHeaders.set("Accept", "application/xml");
	requestHeaders.set("Content-Type", "application/xml");

	String xmlStr = "<userDTOX><name>Jack</name><age>16</age></userDTOX>";

	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).我們甚至可以任意組合請求和應答中的XML/JSON。比如Request=XML，Response=JSON

@Test
public void testXmlRequestJsonResponse() throws IOException, URISyntaxException {
		String url = "http://localhost:8080/SpringMVC/createUser";
		HttpHeaders requestHeaders = new HttpHeaders();
		requestHeaders.set("Accept", "application/json");
		requestHeaders.set("Content-Type", "application/xml");
		
		String xmlStr = "<userDTOX><name>Jack</name><age>16</age></userDTOX>";

		RestTemplate restTemplate = new RestTemplate();
		HttpEntity<String> httpEntity = new HttpEntity<String>(xmlStr, requestHeaders);
		String jsonData = restTemplate.postForObject(url, httpEntity, String.class);

		System.out.println(jsonData);
}
           

        類似上一篇中的分析，最關鍵的處理在AbstractMessageConverterMethodArgumentResolver.readWithMessageConverters()。它會根據request header中的Content-Type屬性來選擇合适的message converter。

        另外，如果不想使用<mvc:annotation-driven/>中預設的RequestMappingHandlerAdapter的話，我們可以在重新定義這個bean，spring會覆寫掉預設的RequestMappingHandlerAdapter。

<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>      

        或者如果隻想換messageConverters的話。

<mvc:annotation-driven>
  <mvc:message-converters>
    <bean class="org.example.MyHttpMessageConverter"/>
    <bean class="org.example.MyOtherHttpMessageConverter"/>
  </mvc:message-converters>
</mvc:annotation-driven>
           

文章來源：http://blog.csdn.net/fw0124/article/details/48312317