前面介紹過Spring的MVC結合不同的view顯示不同的數據,如:結合json的 view顯示json、結合xml的view顯示xml文檔。那么這些數據除了在WebBrowser中用JavaScript來調用以外,還可以用遠程 服務器的Java程序、C#程序來調用。也就是說現在的程序不僅在BS中能調用,在CS中同樣也能調用,不過你需要借助RestTemplate這個類來 完成。RestTemplate有點類似于一個WebService客戶端請求的模版,可以調用http請求的WebService,并將結果轉換成相應 的對象類型。至少你可以這樣理解!
上一次博文介紹SpringMVC結合不同的View,顯示不同的數據。http://www.cnblogs.com/hoojo/archive/2011/04/29/2032571.html
Email:hoojo_@126.com
Blog:http://blog.csdn.net/IBM_hoojo
一、準備工作
1、 下載jar包
spring各版本jar下載地址:http://ebr.springsource.com/repository/app/library/detail?name=org.springframework.spring
相關的依賴包也可以在這里找到:http://ebr.springsource.com/repository/app/library
2、 需要jar包如下
3、 當前工程的web.xml配置
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">
<!-- 配置Spring核心控制器 -->
<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/dispatcher.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>*.do</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
4、 WEB-INF中的dispatcher.xml配置
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:util="http://www.springframework.org/schema/util"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd
http://www.springframework.org/schema/util
http://www.springframework.org/schema/util/spring-util-3.0.xsd">
<context:component-scan base-package="com.hoo.*">
<!-- 忽略這個類 -->
<context:exclude-filter type="assignable" expression="com.hoo.client.RESTClient"/>
</context:component-scan>
<!-- annotation的方法映射適配器 -->
<bean id="handlerAdapter" class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter"/>
<!-- xml視圖,XStreamMarshaller,可以轉換任何形式的java對象 -->
<bean name="xStreamMarshallingView" class="org.springframework.web.servlet.view.xml.MarshallingView">
<property name="marshaller">
<bean class="org.springframework.oxm.xstream.XStreamMarshaller">
<!-- 為了初始化XStreamMarshaller,這個類會把我們接口中得到結果以XML文檔形式展現出來 -->
<property name="autodetectAnnotations" value="true"/>
</bean>
</property>
</bean>
<!-- 視圖解析器,根據視圖的名稱new ModelAndView(name),在配置文件查找對應的bean配置 -->
<bean class="org.springframework.web.servlet.view.BeanNameViewResolver">
<property name="order" value="3"/>
</bean>
<!-- annotation默認的方法映射適配器 -->
<bean id="handlerMapping" class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">
<property name="order" value="1" />
</bean>
</beans>
5、 啟動后,可以看到index.jsp 沒有出現異常或錯誤。那么當前SpringMVC的配置就成功了。
二、REST控制器實現
REST控制器主要完成CRUD操作,也就是對于http中的post、get、put、delete。
還有其他的操作,如head、options、trace。
具體代碼:
package com.hoo.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
/**
* <b>function:</b>SpringMVC REST示例
* @author hoojo
* @createDate 2011-6-9 上午11:34:08
* @file RESTController.java
* @package com.hoo.controller
* @project SpringRestWS
* @blog http://blog.csdn.net/IBM_hoojo
* @email hoojo_@126.com
* @version 1.0
*/
@RequestMapping("/restful")
@Controller
public class RESTController {
@RequestMapping(value = "/show", method = RequestMethod.GET)
public ModelAndView show() {
System.out.println("show");
ModelAndView model = new ModelAndView("xStreamMarshallingView");
model.addObject("show method");
return model;
}
@RequestMapping(value = "/get/{id}", method = RequestMethod.GET)
public ModelAndView getUserById(@PathVariable String id) {
System.out.println("getUserById-" + id);
ModelAndView model = new ModelAndView("xStreamMarshallingView");
model.addObject("getUserById method -" + id);
return model;
}
@RequestMapping(value = "/add", method = RequestMethod.POST)
public ModelAndView addUser(String user) {
System.out.println("addUser-" + user);
ModelAndView model = new ModelAndView("xStreamMarshallingView");
model.addObject("addUser method -" + user);
return model;
}
@RequestMapping(value = "/edit", method = RequestMethod.PUT)
public ModelAndView editUser(String user) {
System.out.println("editUser-" + user);
ModelAndView model = new ModelAndView("xStreamMarshallingView");
model.addObject("editUser method -" + user);
return model;
}
@RequestMapping(value = "/remove/{id}", method = RequestMethod.DELETE)
public ModelAndView removeUser(@PathVariable String id) {
System.out.println("removeUser-" + id);
ModelAndView model = new ModelAndView("xStreamMarshallingView");
model.addObject("removeUser method -" + id);
return model;
}
}
上面的方法對應的http操作:
/show -> get 查詢
/get/id -> get 查詢
/add -> post 添加
/edit -> put 修改
/remove/id -> delete 刪除
在這個方法中,就可以看到RESTful風格的url資源標識
@RequestMapping(value = "/get/{id}", method = RequestMethod.GET)
public ModelAndView getUserById(@PathVariable String id) {
System.out.println("getUserById-" + id);
ModelAndView model = new ModelAndView("xStreamMarshallingView");
model.addObject("getUserById method -" + id);
return model;
}
value=”/get/{id}”就是url中包含get,并且帶有id參數的get請求,就會執行這個方法。這個url在請求的時候,會通過 Annotation的@PathVariable來將url中的id值設置到getUserById的參數中去。 ModelAndView返回的視圖是xStreamMarshallingView是一個xml視圖,執行當前請求后,會顯示一篇xml文檔。文檔的內 容是添加到model中的值。
三、利用RestTemplate調用REST資源
代碼如下:
package com.hoo.client;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.client.RestTemplate;
/**
* <b>function:</b>RestTemplate調用REST資源
* @author hoojo
* @createDate 2011-6-9 上午11:56:16
* @file RESTClient.java
* @package com.hoo.client
* @project SpringRestWS
* @blog http://blog.csdn.net/IBM_hoojo
* @email hoojo_@126.com
* @version 1.0
*/
@Component
public class RESTClient {
@Autowired
private RestTemplate template;
private final static String url = "http://localhost:8080/SpringRestWS/restful/";
public String show() {
return template.getForObject(url + "show.do", String.class, new String[]{});
}
public String getUserById(String id) {
return template.getForObject(url + "get/{id}.do", String.class, id);
}
public String addUser(String user) {
return template.postForObject(url + "add.do?user={user}", null, String.class, user);
}
public String editUser(String user) {
template.put(url + "edit.do?user={user}", null, user);
return user;
}
public String removeUser(String id) {
template.delete(url + "/remove/{id}.do", id);
return id;
}
}
RestTemplate的getForObject完成get請求、postForObject完成post請求、put對應的完成put請求、 delete完成delete請求;還有execute可以執行任何請求的方法,需要你設置RequestMethod來指定當前請求類型。
RestTemplate.getForObject(String url, Class<String> responseType, String... urlVariables)
參數url是http請求的地址,參數Class是請求響應返回后的數據的類型,最后一個參數是請求中需要設置的參數。
template.getForObject(url + "get/{id}.do", String.class, id);
如上面的參數是{id},返回的是一個string類型,設置的參數是id。最后執行該方法會返回一個String類型的結果。
下面建立一個測試類,完成對RESTClient的測試。代碼如下:
package com.hoo.client;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit38.AbstractJUnit38SpringContextTests;
/**
* <b>function:</b>RESTClient TEST
* @author hoojo
* @createDate 2011-6-9 下午03:50:21
* @file RESTClientTest.java
* @package com.hoo.client
* @project SpringRestWS
* @blog http://blog.csdn.net/IBM_hoojo
* @email hoojo_@126.com
* @version 1.0
*/
@ContextConfiguration("classpath:applicationContext-*.xml")
public class RESTClientTest extends AbstractJUnit38SpringContextTests {
@Autowired
private RESTClient client;
public void testShow() {
System.out.println(client.show());
}
public void testGetUserById() {
System.out.println(client.getUserById("abc"));
}
public void testAddUser() {
System.out.println(client.addUser("jack"));
}
public void testEditUser() {
System.out.println(client.editUser("tom"));
}
public void testRemoveUser() {
System.out.println(client.removeUser("aabb"));
}
}
我們需要在src目錄下添加applicationContext-beans.xml完成對restTemplate的配置。restTemplate需要配置MessageConvert將返回的xml文檔進行轉換,解析成JavaObject。
<?xml version="1.0" encoding="UTF-8"?>
<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"
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.hoo.*"/>
<bean id="restTemplate" class="org.springframework.web.client.RestTemplate">
<property name="messageConverters">
<list>
<bean class="org.springframework.http.converter.xml.MarshallingHttpMessageConverter">
<property name="marshaller" ref="xStreamMarshaller"/>
<property name="unmarshaller" ref="xStreamMarshaller"/>
</bean>
</list>
</property>
</bean>
<bean id="xStreamMarshaller" class="org.springframework.oxm.xstream.XStreamMarshaller">
<property name="annotatedClasses">
<array>
</array>
</property>
</bean>
</beans>
上面配置了xStreamMarshaller是和RESTController中的ModelAndView的view對應的。因為那邊是用 xStreamMarshaller進行編組的,所以RestTemplate這邊也需要用它來解組。RestTemplate還指出其他的 MarshallingHttpMessageConverter;