spring经典注解实例二 10分钟弄懂

昨天对Spring注解有了一个整体认识，至少完成了一个简单的web应用搭建。当然，还不完善，这仅仅只是个开始！
今天看了Spring 3.0的注解，我感觉自己被颠覆了。多年前，为了减少代码依赖我们用配置文件进行模块间耦合，降低模块之间的黏度。现如今，所有可配置的内容都塞进了代码中，我只能说：这多少有点顾此失彼，有点倒退的意思！使用注解的好处是：代码通读性增强。这既是优势也是劣势！如果我要改一段配置，就要打开代码逐行扫描；如果恰巧这是别人封装的jar包，那我只好反编译；如果碰巧遇上这个jar包经过了混淆，那我只好求助于AOP了。 为了这么一个配置，我的代码观几乎将要被颠覆！


言归正传，研究一下注解下的控制层。
我习惯于使用JSTL展示页面，因此需要在原lib基础上增加jstl.jar和standard.jar，详细lib依赖如下：

引用

aopalliance-1.0.jar
commons-logging-1.1.1.jar
log4j-1.2.15.jar
spring-beans-2.5.6.jar
spring-context-2.5.6.jar
spring-context-support-2.5.6.jar
spring-core-2.5.6.jar
spring-tx-2.5.6.jar
spring-web-2.5.6.jar
spring-webmvc-2.5.6.jar
standard.jar
jstl.jar


上一篇文中，我们定义了控制器AccountController：
AccountController.java

Java代码
1./**
2. * 2010-1-23
3. */
4.package org.zlex.spring.controller;
5.
6.import javax.servlet.http.HttpServletRequest;
7.import javax.servlet.http.HttpServletResponse;
8.
9.import org.springframework.beans.factory.annotation.Autowired;
10.import org.springframework.stereotype.Controller;
11.import org.springframework.web.bind.ServletRequestUtils;
12.import org.springframework.web.bind.annotation.RequestMapping;
13.import org.springframework.web.bind.annotation.RequestMethod;
14.import org.zlex.spring.service.AccountService;
15.
16./**
17. *
18. * @author <a href="mailto:zlex.dongliang@gmail.com">梁栋</a>
19. * @version 1.0
20. * @since 1.0
21. */
22.@Controller
23.@RequestMapping("/account.do")
24.public class AccountController {
25.
26. @Autowired
27. private AccountService accountService;
28.
29. @RequestMapping(method = RequestMethod.GET)
30. public void hello(HttpServletRequest request, HttpServletResponse response)
31. throws Exception {
32.
33. String username = ServletRequestUtils.getRequiredStringParameter(
34. request, "username");
35. String password = ServletRequestUtils.getRequiredStringParameter(
36. request, "password");
37. System.out.println(accountService.verify(username, password));
38. }
39.}
Java代码
1./**
2. * 2010-1-23
3. */
4.package org.zlex.spring.controller;
5.
6.import javax.servlet.http.HttpServletRequest;
7.import javax.servlet.http.HttpServletResponse;
8.
9.import org.springframework.beans.factory.annotation.Autowired;
10.import org.springframework.stereotype.Controller;
11.import org.springframework.web.bind.ServletRequestUtils;
12.import org.springframework.web.bind.annotation.RequestMapping;
13.import org.springframework.web.bind.annotation.RequestMethod;
14.import org.zlex.spring.service.AccountService;
15.
16./**
17. *
18. * @author <a href="mailto:zlex.dongliang@gmail.com">梁栋</a>
19. * @version 1.0
20. * @since 1.0
21. */
22.@Controller
23.@RequestMapping("/account.do")
24.public class AccountController {
25.
26. @Autowired
27. private AccountService accountService;
28.
29. @RequestMapping(method = RequestMethod.GET)
30. public void hello(HttpServletRequest request, HttpServletResponse response)
31. throws Exception {
32.
33. String username = ServletRequestUtils.getRequiredStringParameter(
34. request, "username");
35. String password = ServletRequestUtils.getRequiredStringParameter(
36. request, "password");
37. System.out.println(accountService.verify(username, password));
38. }
39.}
/**
* 2010-1-23
*/
package org.zlex.spring.controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.ServletRequestUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.zlex.spring.service.AccountService;

/**
*
* @author <a href="mailto:zlex.dongliang@gmail.com">梁栋</a>
* @version 1.0
* @since 1.0
*/
@Controller
@RequestMapping("/account.do")
public class AccountController {

@Autowired
private AccountService accountService;

@RequestMapping(method = RequestMethod.GET)
public void hello(HttpServletRequest request, HttpServletResponse response)
throws Exception {

String username = ServletRequestUtils.getRequiredStringParameter(
request, "username");
String password = ServletRequestUtils.getRequiredStringParameter(
request, "password");
System.out.println(accountService.verify(username, password));
}
}

先说注解@RequestMapping
这里使用注解@RequestMapping(method = RequestMethod.GET)指定这个方法为get请求时调用。同样，我们可以使用注解@RequestMapping(method = RequestMethod.POST)指定该方法接受post请求。

Java代码
1.@Controller
2.@RequestMapping("/account.do")
3.public class AccountController {
4.
5. @RequestMapping(method = RequestMethod.GET)
6. public void get() {
7. }
8.
9. @RequestMapping(method = RequestMethod.POST)
10. public void post() {
11. }
12.}
Java代码
1.@Controller
2.@RequestMapping("/account.do")
3.public class AccountController {
4.
5. @RequestMapping(method = RequestMethod.GET)
6. public void get() {
7. }
8.
9. @RequestMapping(method = RequestMethod.POST)
10. public void post() {
11. }
12.}
@Controller
@RequestMapping("/account.do")
public class AccountController {

@RequestMapping(method = RequestMethod.GET)
public void get() {
}

@RequestMapping(method = RequestMethod.POST)
public void post() {
}
}

这与我们久别的Servlet很相像，类似于doGet()和doPost()方法！
我们也可以将其改造为多动作控制器，如下代码所示：

Java代码
1.@Controller
2.@RequestMapping("/account.do")
3.public class AccountController {
4.
5. @RequestMapping(params = "method=login")
6. public void login() {
7. }
8.
9. @RequestMapping(params = "method=logout")
10. public void logout() {
11. }
Java代码
1.@Controller
2.@RequestMapping("/account.do")
3.public class AccountController {
4.
5. @RequestMapping(params = "method=login")
6. public void login() {
7. }
8.
9. @RequestMapping(params = "method=logout")
10. public void logout() {
11. }
@Controller
@RequestMapping("/account.do")
public class AccountController {

@RequestMapping(params = "method=login")
public void login() {
}

@RequestMapping(params = "method=logout")
public void logout() {
}

这样，我们可以通过参数“method”指定不同的参数值从而通过请求（"/account.do?method=login"和"/account.do?method=logout"）调用不同的方法！
注意：使用多动作控制器必须在配置文件中加入注解支持！

Xml代码
1.<bean
2. class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
Xml代码
1.<bean
2. class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
<bean
class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />

当然，我们也可以将注解@RequestMapping指定到某一个方法上，如：

Java代码
1.@Controller
2.public class AccountController {
3.
4. @RequestMapping("/a.do")
5. public void a() {}
6.
7. @RequestMapping("/b.do")
8. public void b() {}
9.}
Java代码
1.@Controller
2.public class AccountController {
3.
4. @RequestMapping("/a.do")
5. public void a() {}
6.
7. @RequestMapping("/b.do")
8. public void b() {}
9.}
@Controller
public class AccountController {

@RequestMapping("/a.do")
public void a() {}

@RequestMapping("/b.do")
public void b() {}
}

这样，请求“a.do”和“b.do”将对应不同的方法a() 和b()。这使得一个控制器可以同时承载多个请求！
@RequestMapping("/account.do")是@RequestMapping(value="/account.do")的简写！
再说输入参数！
这里的方法名可以随意定义，但是参数和返回值却又要求！
为什么？直接看源代码，我们就能找到答案！
AnnotationMethodHandlerAdapter.java部分源代码——有关参数部分：

Java代码
1.@Override
2.protected Object resolveStandardArgument(Class parameterType, NativeWebRequest webRequest)
3. throws Exception {
4.
5. HttpServletRequest request = (HttpServletRequest) webRequest.getNativeRequest();
6. HttpServletResponse response = (HttpServletResponse) webRequest.getNativeResponse();
7.
8. if (ServletRequest.class.isAssignableFrom(parameterType)) {
9. return request;
10. }
11. else if (ServletResponse.class.isAssignableFrom(parameterType)) {
12. this.responseArgumentUsed = true;
13. return response;
14. }
15. else if (HttpSession.class.isAssignableFrom(parameterType)) {
16. return request.getSession();
17. }
18. else if (Principal.class.isAssignableFrom(parameterType)) {
19. return request.getUserPrincipal();
20. }
21. else if (Locale.class.equals(parameterType)) {
22. return RequestContextUtils.getLocale(request);
23. }
24. else if (InputStream.class.isAssignableFrom(parameterType)) {
25. return request.getInputStream();
26. }
27. else if (Reader.class.isAssignableFrom(parameterType)) {
28. return request.getReader();
29. }
30. else if (OutputStream.class.isAssignableFrom(parameterType)) {
31. this.responseArgumentUsed = true;
32. return response.getOutputStream();
33. }
34. else if (Writer.class.isAssignableFrom(parameterType)) {
35. this.responseArgumentUsed = true;
36. return response.getWriter();
37. }
38. return super.resolveStandardArgument(parameterType, webRequest);
39.}
Java代码
1.@Override
2.protected Object resolveStandardArgument(Class parameterType, NativeWebRequest webRequest)
3. throws Exception {
4.
5. HttpServletRequest request = (HttpServletRequest) webRequest.getNativeRequest();
6. HttpServletResponse response = (HttpServletResponse) webRequest.getNativeResponse();
7.
8. if (ServletRequest.class.isAssignableFrom(parameterType)) {
9. return request;
10. }
11. else if (ServletResponse.class.isAssignableFrom(parameterType)) {
12. this.responseArgumentUsed = true;
13. return response;
14. }
15. else if (HttpSession.class.isAssignableFrom(parameterType)) {
16. return request.getSession();
17. }
18. else if (Principal.class.isAssignableFrom(parameterType)) {
19. return request.getUserPrincipal();
20. }
21. else if (Locale.class.equals(parameterType)) {
22. return RequestContextUtils.getLocale(request);
23. }
24. else if (InputStream.class.isAssignableFrom(parameterType)) {
25. return request.getInputStream();
26. }
27. else if (Reader.class.isAssignableFrom(parameterType)) {
28. return request.getReader();
29. }
30. else if (OutputStream.class.isAssignableFrom(parameterType)) {
31. this.responseArgumentUsed = true;
32. return response.getOutputStream();
33. }
34. else if (Writer.class.isAssignableFrom(parameterType)) {
35. this.responseArgumentUsed = true;
36. return response.getWriter();
37. }
38. return super.resolveStandardArgument(parameterType, webRequest);
39.}
@Override
protected Object resolveStandardArgument(Class parameterType, NativeWebRequest webRequest)
throws Exception {

HttpServletRequest request = (HttpServletRequest) webRequest.getNativeRequest();
HttpServletResponse response = (HttpServletResponse) webRequest.getNativeResponse();

if (ServletRequest.class.isAssignableFrom(parameterType)) {
return request;
}
else if (ServletResponse.class.isAssignableFrom(parameterType)) {
this.responseArgumentUsed = true;
return response;
}
else if (HttpSession.class.isAssignableFrom(parameterType)) {
return request.getSession();
}
else if (Principal.class.isAssignableFrom(parameterType)) {
return request.getUserPrincipal();
}
else if (Locale.class.equals(parameterType)) {
return RequestContextUtils.getLocale(request);
}
else if (InputStream.class.isAssignableFrom(parameterType)) {
return request.getInputStream();
}
else if (Reader.class.isAssignableFrom(parameterType)) {
return request.getReader();
}
else if (OutputStream.class.isAssignableFrom(parameterType)) {
this.responseArgumentUsed = true;
return response.getOutputStream();
}
else if (Writer.class.isAssignableFrom(parameterType)) {
this.responseArgumentUsed = true;
return response.getWriter();
}
return super.resolveStandardArgument(parameterType, webRequest);
}

也就是说，如果我们想要在自定义的方法中获得一些个“标准”输入参数，参数类型必须包含在以下类型中：

引用

ServletRequest
ServletResponse
HttpSession
Principal
Locale
InputStream
OutputStream
Reader
Writer


当然，上述接口其实都是对于HttpServletRequest和HttpServletResponse的扩展。
此外，我们还可以定义自己的参数。
注意：自定义参数必须是实现类，绝非接口！Spring容器将帮你完成对象初始化工作！
比如说上文中，我们需要参数username和password。我们可以这么写：

Java代码
1.@RequestMapping(method = RequestMethod.GET)
2.public void hello(String username,String password) {
3. System.out.println(accountService.verify(username, password));
4.}
Java代码
1.@RequestMapping(method = RequestMethod.GET)
2.public void hello(String username,String password) {
3. System.out.println(accountService.verify(username, password));
4.}
@RequestMapping(method = RequestMethod.GET)
public void hello(String username,String password) {
System.out.println(accountService.verify(username, password));
}

如果参数名不能与这里的变量名保持一致，那么我们可以使用注解@RequestParam进行强制绑定，代码如下所示：

Java代码
1.@RequestMapping(method = RequestMethod.GET)
2.public void hello(@RequestParam("username") String u,
3. @RequestParam("password") String p) {
4. System.out.println(accountService.verify(u, p));
5.}
Java代码
1.@RequestMapping(method = RequestMethod.GET)
2.public void hello(@RequestParam("username") String u,
3. @RequestParam("password") String p) {
4. System.out.println(accountService.verify(u, p));
5.}
@RequestMapping(method = RequestMethod.GET)
public void hello(@RequestParam("username") String u,
@RequestParam("password") String p) {
System.out.println(accountService.verify(u, p));
}

这比起我们之前写的代码有所简洁：

Java代码
1.@RequestMapping(method = RequestMethod.GET)
2.public void hello(HttpServletRequest request, HttpServletResponse response)
3. throws Exception {
4.
5. String username = ServletRequestUtils.getRequiredStringParameter(
6. request, "username");
7. String password = ServletRequestUtils.getRequiredStringParameter(
8. request, "password");
9. System.out.println(accountService.verify(username, password));
10.}
Java代码
1.@RequestMapping(method = RequestMethod.GET)
2.public void hello(HttpServletRequest request, HttpServletResponse response)
3. throws Exception {
4.
5. String username = ServletRequestUtils.getRequiredStringParameter(
6. request, "username");
7. String password = ServletRequestUtils.getRequiredStringParameter(
8. request, "password");
9. System.out.println(accountService.verify(username, password));
10.}
@RequestMapping(method = RequestMethod.GET)
public void hello(HttpServletRequest request, HttpServletResponse response)
throws Exception {

String username = ServletRequestUtils.getRequiredStringParameter(
request, "username");
String password = ServletRequestUtils.getRequiredStringParameter(
request, "password");
System.out.println(accountService.verify(username, password));
}

ServletRequestUtils类的工作已经由Spring底层实现了，我们只需要把参数名定义一致即可，其内部取参无需关心！
除了传入参数，我们还可以定义即将传出的参数，如加入ModelMap参数：

Java代码
1.@SuppressWarnings("unchecked")
2.@RequestMapping(method = RequestMethod.GET)
3.public Map hello(String username, String password, ModelMap model) {
4.
5. System.out.println(accountService.verify(username, password));
6.
7. model.put("msg", username);
8.
9. return model;
10.}
Java代码
1.@SuppressWarnings("unchecked")
2.@RequestMapping(method = RequestMethod.GET)
3.public Map hello(String username, String password, ModelMap model) {
4.
5. System.out.println(accountService.verify(username, password));
6.
7. model.put("msg", username);
8.
9. return model;
10.}
@SuppressWarnings("unchecked")
@RequestMapping(method = RequestMethod.GET)
public Map hello(String username, String password, ModelMap model) {

System.out.println(accountService.verify(username, password));

model.put("msg", username);

return model;
}

这时，我们没有定义页面名称，Spring容器将根据请求名指定同名view，即如果是jap页面，则account.do->account.jsp！
不得不承认，这样写起来的确减少了代码量！
接着说输出参数！
通过ModelMap，我们可以绑定输出到的页面的参数，但最终我们将要返回到何种页面呢？再次查看AnnotationMethodHandlerAdapter源代码！
AnnotationMethodHandlerAdapter.java部分源代码——有关返回值部分：

Java代码
1.@SuppressWarnings("unchecked")
2.public ModelAndView getModelAndView(Method handlerMethod, Class handlerType, Object returnValue,
3. ExtendedModelMap implicitModel, ServletWebRequest webRequest) {
4.
5. if (returnValue instanceof ModelAndView) {
6. ModelAndView mav = (ModelAndView) returnValue;
7. mav.getModelMap().mergeAttributes(implicitModel);
8. return mav;
9. }
10. else if (returnValue instanceof Model) {
11. return new ModelAndView().addAllObjects(implicitModel).addAllObjects(((Model) returnValue).asMap());
12. }
13. else if (returnValue instanceof Map) {
14. return new ModelAndView().addAllObjects(implicitModel).addAllObjects((Map) returnValue);
15. }
16. else if (returnValue instanceof View) {
17. return new ModelAndView((View) returnValue).addAllObjects(implicitModel);
18. }
19. else if (returnValue instanceof String) {
20. return new ModelAndView((String) returnValue).addAllObjects(implicitModel);
21. }
22. else if (returnValue == null) {
23. // Either returned null or was 'void' return.
24. if (this.responseArgumentUsed || webRequest.isNotModified()) {
25. return null;
26. }
27. else {
28. // Assuming view name translation...
29. return new ModelAndView().addAllObjects(implicitModel);
30. }
31. }
32. else if (!BeanUtils.isSimpleProperty(returnValue.getClass())) {
33. // Assume a single model attribute...
34. ModelAttribute attr = AnnotationUtils.findAnnotation(handlerMethod, ModelAttribute.class);
35. String attrName = (attr != null ? attr.value() : "");
36. ModelAndView mav = new ModelAndView().addAllObjects(implicitModel);
37. if ("".equals(attrName)) {
38. Class resolvedType = GenericTypeResolver.resolveReturnType(handlerMethod, handlerType);
39. attrName = Conventions.getVariableNameForReturnType(handlerMethod, resolvedType, returnValue);
40. }
41. return mav.addObject(attrName, returnValue);
42. }
43. else {
44. throw new IllegalArgumentException("Invalid handler method return value: " + returnValue);
45. }
46.}
Java代码
1.@SuppressWarnings("unchecked")
2.public ModelAndView getModelAndView(Method handlerMethod, Class handlerType, Object returnValue,
3. ExtendedModelMap implicitModel, ServletWebRequest webRequest) {
4.
5. if (returnValue instanceof ModelAndView) {
6. ModelAndView mav = (ModelAndView) returnValue;
7. mav.getModelMap().mergeAttributes(implicitModel);
8. return mav;
9. }
10. else if (returnValue instanceof Model) {
11. return new ModelAndView().addAllObjects(implicitModel).addAllObjects(((Model) returnValue).asMap());
12. }
13. else if (returnValue instanceof Map) {
14. return new ModelAndView().addAllObjects(implicitModel).addAllObjects((Map) returnValue);
15. }
16. else if (returnValue instanceof View) {
17. return new ModelAndView((View) returnValue).addAllObjects(implicitModel);
18. }
19. else if (returnValue instanceof String) {
20. return new ModelAndView((String) returnValue).addAllObjects(implicitModel);
21. }
22. else if (returnValue == null) {
23. // Either returned null or was 'void' return.
24. if (this.responseArgumentUsed || webRequest.isNotModified()) {
25. return null;
26. }
27. else {
28. // Assuming view name translation...
29. return new ModelAndView().addAllObjects(implicitModel);
30. }
31. }
32. else if (!BeanUtils.isSimpleProperty(returnValue.getClass())) {
33. // Assume a single model attribute...
34. ModelAttribute attr = AnnotationUtils.findAnnotation(handlerMethod, ModelAttribute.class);
35. String attrName = (attr != null ? attr.value() : "");
36. ModelAndView mav = new ModelAndView().addAllObjects(implicitModel);
37. if ("".equals(attrName)) {
38. Class resolvedType = GenericTypeResolver.resolveReturnType(handlerMethod, handlerType);
39. attrName = Conventions.getVariableNameForReturnType(handlerMethod, resolvedType, returnValue);
40. }
41. return mav.addObject(attrName, returnValue);
42. }
43. else {
44. throw new IllegalArgumentException("Invalid handler method return value: " + returnValue);
45. }
46.}
@SuppressWarnings("unchecked")
public ModelAndView getModelAndView(Method handlerMethod, Class handlerType, Object returnValue,
ExtendedModelMap implicitModel, ServletWebRequest webRequest) {

if (returnValue instanceof ModelAndView) {
ModelAndView mav = (ModelAndView) returnValue;
mav.getModelMap().mergeAttributes(implicitModel);
return mav;
}
else if (returnValue instanceof Model) {
return new ModelAndView().addAllObjects(implicitModel).addAllObjects(((Model) returnValue).asMap());
}
else if (returnValue instanceof Map) {
return new ModelAndView().addAllObjects(implicitModel).addAllObjects((Map) returnValue);
}
else if (returnValue instanceof View) {
return new ModelAndView((View) returnValue).addAllObjects(implicitModel);
}
else if (returnValue instanceof String) {
return new ModelAndView((String) returnValue).addAllObjects(implicitModel);
}
else if (returnValue == null) {
// Either returned null or was 'void' return.
if (this.responseArgumentUsed || webRequest.isNotModified()) {
return null;
}
else {
// Assuming view name translation...
return new ModelAndView().addAllObjects(implicitModel);
}
}
else if (!BeanUtils.isSimpleProperty(returnValue.getClass())) {
// Assume a single model attribute...
ModelAttribute attr = AnnotationUtils.findAnnotation(handlerMethod, ModelAttribute.class);
String attrName = (attr != null ? attr.value() : "");
ModelAndView mav = new ModelAndView().addAllObjects(implicitModel);
if ("".equals(attrName)) {
Class resolvedType = GenericTypeResolver.resolveReturnType(handlerMethod, handlerType);
attrName = Conventions.getVariableNameForReturnType(handlerMethod, resolvedType, returnValue);
}
return mav.addObject(attrName, returnValue);
}
else {
throw new IllegalArgumentException("Invalid handler method return value: " + returnValue);
}
}
}

返回值的定义十分庞大，或者说可怕的if-else多少有点让我觉得厌恶！
我们可以定义以下类型的返回值：

引用

ModelAndView
Model
View
Map
String
null


ModelAndView、Model和View都是Spring之前版本所特有的元素，Map对应于传入参数ModelMap，String定义页面名称，null即对应void类型方法！
最常用的实现方式如下：

Java代码
1.@SuppressWarnings("unchecked")
2.@RequestMapping(method = RequestMethod.GET)
3.public String hello(String username, String password, ModelMap model) {
4.
5. System.out.println(accountService.verify(username, password));
6.
7. model.put("msg", username);
8.
9. return "account";
10.}
Java代码
1.@SuppressWarnings("unchecked")
2.@RequestMapping(method = RequestMethod.GET)
3.public String hello(String username, String password, ModelMap model) {
4.
5. System.out.println(accountService.verify(username, password));
6.
7. model.put("msg", username);
8.
9. return "account";
10.}
@SuppressWarnings("unchecked")
@RequestMapping(method = RequestMethod.GET)
public String hello(String username, String password, ModelMap model) {

System.out.println(accountService.verify(username, password));

model.put("msg", username);

return "account";
}

当然，对于我来说在返回值中写入这么一个字符串多少有点不能接受，于是我还是乐于使用输入参数ModelMap+输出参数Map的方式。
给出一个完整的AccountController实现：
AccountController.java

Java代码
1./**
2. * 2010-1-23
3. */
4.package org.zlex.spring.controller;
5.
6.import java.util.Map;
7.
8.import org.springframework.beans.factory.annotation.Autowired;
9.import org.springframework.stereotype.Controller;
10.import org.springframework.ui.ModelMap;
11.import org.springframework.web.bind.annotation.RequestMapping;
12.import org.springframework.web.bind.annotation.RequestMethod;
13.import org.zlex.spring.service.AccountService;
14.
15./**
16. *
17. * @author <a href="mailto:zlex.dongliang@gmail.com">梁栋</a>
18. * @version 1.0
19. * @since 1.0
20. */
21.@Controller
22.@RequestMapping("/account.do")
23.public class AccountController {
24.
25. @Autowired
26. private AccountService accountService;
27.
28. @SuppressWarnings("unchecked")
29. @RequestMapping(method = RequestMethod.GET)
30. public Map hello(String username, String password, ModelMap model) {
31.
32. System.out.println(accountService.verify(username, password));
33.
34. model.put("msg", username);
35. return model;
36. }
37.}
Java代码
1./**
2. * 2010-1-23
3. */
4.package org.zlex.spring.controller;
5.
6.import java.util.Map;
7.
8.import org.springframework.beans.factory.annotation.Autowired;
9.import org.springframework.stereotype.Controller;
10.import org.springframework.ui.ModelMap;
11.import org.springframework.web.bind.annotation.RequestMapping;
12.import org.springframework.web.bind.annotation.RequestMethod;
13.import org.zlex.spring.service.AccountService;
14.
15./**
16. *
17. * @author <a href="mailto:zlex.dongliang@gmail.com">梁栋</a>
18. * @version 1.0
19. * @since 1.0
20. */
21.@Controller
22.@RequestMapping("/account.do")
23.public class AccountController {
24.
25. @Autowired
26. private AccountService accountService;
27.
28. @SuppressWarnings("unchecked")
29. @RequestMapping(method = RequestMethod.GET)
30. public Map hello(String username, String password, ModelMap model) {
31.
32. System.out.println(accountService.verify(username, password));
33.
34. model.put("msg", username);
35. return model;
36. }
37.}
/**
* 2010-1-23
*/
package org.zlex.spring.controller;

import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.zlex.spring.service.AccountService;

/**
*
* @author <a href="mailto:zlex.dongliang@gmail.com">梁栋</a>
* @version 1.0
* @since 1.0
*/
@Controller
@RequestMapping("/account.do")
public class AccountController {

@Autowired
private AccountService accountService;

@SuppressWarnings("unchecked")
@RequestMapping(method = RequestMethod.GET)
public Map hello(String username, String password, ModelMap model) {

System.out.println(accountService.verify(username, password));

model.put("msg", username);
return model;
}
}

最后说注解@Session
如果想将某个ModelMap中的参数指定到Session中，可以使用@Session注解，将其绑定为Session熟悉，代码如下所示：

Java代码
1.@Controller
2.@RequestMapping("/account.do")
3.@SessionAttributes("msg")
4.public class AccountController {
5.
6. @Autowired
7. private AccountService accountService;
8.
9. @SuppressWarnings("unchecked")
10. @RequestMapping(method = RequestMethod.GET)
11. public Map hello(String username, String password, ModelMap model) {
12.
13. System.out.println(accountService.verify(username, password));
14.
15. model.put("msg", username);
16. return model;
17. }
18.
19.}
Java代码
1.@Controller
2.@RequestMapping("/account.do")
3.@SessionAttributes("msg")
4.public class AccountController {
5.
6. @Autowired
7. private AccountService accountService;
8.
9. @SuppressWarnings("unchecked")
10. @RequestMapping(method = RequestMethod.GET)
11. public Map hello(String username, String password, ModelMap model) {
12.
13. System.out.println(accountService.verify(username, password));
14.
15. model.put("msg", username);
16. return model;
17. }
18.
19.}
@Controller
@RequestMapping("/account.do")
@SessionAttributes("msg")
public class AccountController {

@Autowired
private AccountService accountService;

@SuppressWarnings("unchecked")
@RequestMapping(method = RequestMethod.GET)
public Map hello(String username, String password, ModelMap model) {

System.out.println(accountService.verify(username, password));

model.put("msg", username);
return model;
}

}

当然，我们还需要配置一下对应的视图解析器，给出完整配置：
servelt.xml

Xml代码
1.<?xml version="1.0" encoding="UTF-8"?>
2.<beans
3. xmlns="http://www.springframework.org/schema/beans"
4. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
5. xmlns:p="http://www.springframework.org/schema/p"
6. xmlns:context="http://www.springframework.org/schema/context"
7. xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
8. http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
9. <context:component-scan
10. base-package="org.zlex.spring.controller" />
11. <bean
12. id="urlMapping"
13. class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />
14. <bean
15. class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
16. <bean
17. id="jstlViewResolver"
18. class="org.springframework.web.servlet.view.InternalResourceViewResolver"
19. p:viewClass="org.springframework.web.servlet.view.JstlView"
20. p:prefix="/WEB-INF/page/"
21. p:suffix=".jsp" />
22.</beans>
Xml代码
1.<?xml version="1.0" encoding="UTF-8"?>
2.<beans
3. xmlns="http://www.springframework.org/schema/beans"
4. xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
5. xmlns:p="http://www.springframework.org/schema/p"
6. xmlns:context="http://www.springframework.org/schema/context"
7. xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
8. http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
9. <context:component-scan
10. base-package="org.zlex.spring.controller" />
11. <bean
12. id="urlMapping"
13. class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />
14. <bean
15. class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
16. <bean
17. id="jstlViewResolver"
18. class="org.springframework.web.servlet.view.InternalResourceViewResolver"
19. p:viewClass="org.springframework.web.servlet.view.JstlView"
20. p:prefix="/WEB-INF/page/"
21. p:suffix=".jsp" />
22.</beans>
<?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:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
<context:component-scan
base-package="org.zlex.spring.controller" />
<bean
id="urlMapping"
class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" />
<bean
class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
<bean
id="jstlViewResolver"
class="org.springframework.web.servlet.view.InternalResourceViewResolver"
p:viewClass="org.springframework.web.servlet.view.JstlView"
p:prefix="/WEB-INF/page/"
p:suffix=".jsp" />
</beans>

这里使用了JstlView作为视图解析器。同时，指定前缀路径为"/WEB-INF/page/"，后缀路径为".jsp"。也就是说，Spring容器将会在这个路径中寻找匹配的jsp文件！
注意加入xmlns:p="http://www.springframework.org/schema/p"命名空间！
再给出页面内容：
taglib.jsp

Jsp代码
1.<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
2.<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt"%>
3.<%@ taglib prefix="sql" uri="http://java.sun.com/jsp/jstl/sql"%>
4.<%@ taglib prefix="x" uri="http://java.sun.com/jsp/jstl/xml"%>
5.<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>
6.<%@ taglib prefix="spring" uri="http://www.springframework.org/tags"%>
7.<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
Jsp代码
1.<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
2.<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt"%>
3.<%@ taglib prefix="sql" uri="http://java.sun.com/jsp/jstl/sql"%>
4.<%@ taglib prefix="x" uri="http://java.sun.com/jsp/jstl/xml"%>
5.<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>
6.<%@ taglib prefix="spring" uri="http://www.springframework.org/tags"%>
7.<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt"%>
<%@ taglib prefix="sql" uri="http://java.sun.com/jsp/jstl/sql"%>
<%@ taglib prefix="x" uri="http://java.sun.com/jsp/jstl/xml"%>
<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>
<%@ taglib prefix="spring" uri="http://www.springframework.org/tags"%>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form"%>

account.jap

Jsp代码
1.<%@ page language="java" contentType="text/html; charset=UTF-8"
2. pageEncoding="UTF-8"%>
3.<%@ include file="/WEB-INF/page/taglib.jsp"%>
4.<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
5.<html>
6.<head>
7.<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
8.<title>Account</title>
9.</head>
10.<body>
11.<c:out value="${msg}"></c:out>
12.</body>
13.</html>
Jsp代码
1.<%@ page language="java" contentType="text/html; charset=UTF-8"
2. pageEncoding="UTF-8"%>
3.<%@ include file="/WEB-INF/page/taglib.jsp"%>
4.<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
5.<html>
6.<head>
7.<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
8.<title>Account</title>
9.</head>
10.<body>
11.<c:out value="${msg}"></c:out>
12.</body>
13.</html>
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ include file="/WEB-INF/page/taglib.jsp"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Account</title>
</head>
<body>
<c:out value="${msg}"></c:out>
</body>
</html>

目录结构如图所示：

启动应用，最后将得到一个带有内容的页面，如图：

代码见附件！