SpringMVC

自己配置的第一个基于spring框架的简单登录程序（不含验证，有简单的拦截功能，也没有事务）

简单说下自己的理解，可能有错误欢迎大家指正补充，也希望自己能借此更进一步，谢谢了。

发送请求request----》到达服务器端由servlet容器分派------》相应的servlet处理完返回结果由servlet容器根据结果处理响应-----》response

springMVC中dispacherServlet继承HttpServlet，我们现在web.xml里面配置servlet

1   <servlet>
2       <servlet-name>springmvc</servlet-name>
3       <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
4       <init-param>
5           <param-name>contextConfigLocation</param-name>
6           <param-value>classpath:springmvc-servlet.xml</param-value>
7       </init-param>
8       <load-on-startup>1</load-on-startup>
9   </servlet>
10
11   <servlet-mapping>
12       <servlet-name>springmvc</servlet-name>
13       <url-pattern>/</url-pattern>
14   </servlet-mapping>

作用域是所有的jsp网页

servlet根据注解通过反射开始执行响应流程

先配置

springmvc-servlet.xml

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:tx="http://www.springframework.org/schema/tx"
6     xmlns:context="http://www.springframework.org/schema/context"
7     xmlns:mvc="http://www.springframework.org/schema/mvc"
8     xsi:schemaLocation="http://www.springframework.org/schema/beans
9     http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
10     http://www.springframework.org/schema/tx
11     http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
12     http://www.springframework.org/schema/context
13     http://www.springframework.org/schema/context/spring-context-3.0.xsd
14     http://www.springframework.org/schema/mvc
15     http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">
16
17
18     <!-- 自动扫描的包名 -->
19     <context:component-scan base-package="com.zhanghaobo" ></context:component-scan>
20      <!-- 默认的注解映射的支持 -->
21     <mvc:annotation-driven />
22     <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
23
24         <property name="prefix" value="/WEB-INF/jsp/"/>
25         <property name="suffix" value=".jsp"/>
26 </bean>
27
28      <bean class="org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter" />
29
30      <!-- 对静态资源文件的访问  -->
31      <mvc:default-servlet-handler/>
32     <!--作用全局的拦截器-->
33      <mvc:interceptors>
34          <bean class="com.zhanghaobo.interceptor.MyAllInterceptor"></bean>
35
36      </mvc:interceptors>
37
38 </beans>

dispatherservlet通过handlermapping执行响应的操作（interceptor,handler）

拦截器就在此执行操作

识别都是通过注解的方式反射得到的所以我们要将执行的类@Controller

@RequestMapping相当于要struts2中的action配置myFirst对应的class不过这个可以直接作用于方法更灵活，不知道理解的对不对

1 import org.springframework.stereotype.Controller;
2 import org.springframework.ui.Model;
3 import org.springframework.web.bind.annotation.RequestMapping;
4 import org.springframework.web.bind.annotation.RequestMethod;
5
6 @Controller
7 public class MyController {
8     @RequestMapping(value="/myFirst",method=RequestMethod.POST)
9     public String hello(String username,String password,Model model){
10         model.addAttribute("username", username);
11         model.addAttribute("password", password);
12         System.out.println(username+password);
13         return "hello";
14     }
15 }

拦截器在调用方法前会执行

1 import java.util.Map;
2
3 import javax.servlet.http.HttpServletRequest;
4 import javax.servlet.http.HttpServletResponse;
5
6 import org.springframework.web.servlet.HandlerInterceptor;
7 import org.springframework.web.servlet.ModelAndView;
8
9 public class MyAllInterceptor implements HandlerInterceptor {
10
11     @Override
12     public boolean preHandle(HttpServletRequest request,
13             HttpServletResponse response, Object handler) throws Exception {
14         if("admin".equals(request.getParameter("username"))&&"admin".equals(request.getParameter("password"))){
15             System.out.println("pre invoke");
16             System.out.println(handler);
17             return true;
18         }
19         response.sendRedirect("index.jsp");
20         System.out.println("print agin");
21         return false;
22     }
23
24     @Override
25     public void postHandle(HttpServletRequest request,
26             HttpServletResponse response, Object handler,
27             ModelAndView modelAndView) throws Exception {
28         Map<String, Object> mm=modelAndView.getModel();
29         for(String key:mm.keySet()){
30             System.out.println(key+"-=======================-");
31             mm.put("username", "张三");
32             mm.put("password", "sdadsa");
33         }
34         System.out.println(modelAndView);
35
36
37     }
38
39     @Override
40     public void afterCompletion(HttpServletRequest request,
41             HttpServletResponse response, Object handler, Exception ex)
42             throws Exception {
43
44         System.out.println("over");
45     }
46
47 }

拦截器要实现HandlerInterceptor，也可以根据需要选择继承（接口适配器）先执行prehandler执行成功才会下步执行响应的controller方法，接着调用posthandler这就是为什么参数里会有一个ModelAndView类型的参数，此类型有个model属性存放参数信息，我们可以打印出来，也可以修改model里面的信息，最后通过视图解析传回客户端。

1  <form action="myFirst" method="post">
2         username:<input type="text" name="username"><br>
3         password:<input type="password" name="password"><br>
4         <input type="submit" value="submit">
5     </form>

返回的客户端页面hello.jsp

1 <body>
2
3     user:${username}
4         pass:${password}
5   </body>

页面结果： user:张三 pass:sdadsa

控制台输出结果：

print agin
pre invoke
public java.lang.String com.zhanghaobo.MyController.hello(java.lang.String,java.lang.String,org.springframework.ui.Model)
adminadmin
username-=======================-
password-=======================-
ModelAndView: reference to view with name 'hello'; model is {username=张三, password=sdadsa}
over

转载于:https://www.cnblogs.com/oldcownotGiveup/p/5395185.html