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java之Maven配置和springMvc的簡單應用，mavenspringmvc

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java之Maven配置和springMvc的簡單應用，mavenspringmvc

初始springMvc這個框架，非常的陌生，而且幸好公司是通過maven這個代碼管理工具，可以隨時添加依賴。解決了很多問題在以後深入開發中。

項目結構：

通過結構中，pom.xml這個文件其實就說明這個項目是通過maven構建的，pom.xml裡是主要負責構建jar或者war的依賴。其代碼如下：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>taofuxn_web</groupId>
    <artifactId>springMvc</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>springMvc Maven Webapp</name>
  <url>http://maven.apache.org</url>
  <dependencies>

    
       <!-- spring需要的jar包 -->  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-context</artifactId>  
            <version>3.2.4.RELEASE</version>  
            <type>jar</type>  
        </dependency>  
  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-core</artifactId>  
            <version>3.2.4.RELEASE</version>  
            <type>jar</type>  
        </dependency>  
  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-beans</artifactId>  
            <version>3.2.4.RELEASE</version>  
            <type>jar</type>  
        </dependency>  
  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-webmvc</artifactId>  
            <version>3.2.4.RELEASE</version>  
            <type>jar</type>  
        </dependency>  
  
        <dependency>  
            <groupId>org.springframework</groupId>  
            <artifactId>spring-orm</artifactId>  
            <version>3.2.4.RELEASE</version>  
            <type>jar</type>  
        </dependency>  
    
    
  </dependencies>
  <build>
    <finalName>springMvc</finalName>
  </build>
</project>

從中可以看出，如果要設置依賴jar，那麼就要知道jar的相關信息。如何得知呢....

尋師問友後，得到了一個站點http://mvnrepository.com/，搜索你要的那個依賴，裡面有相應的版本。

關於springMvc和maven的配置就上面的pom.xml，當然還可以配置Mybxxxs，hibernate..

接下來就要應用springmvc 的相關配置了：

首先配置的是項目中的web.xml，其代碼如下：

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>springmvc</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
  
    <servlet>
        <servlet-name>spring</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
            <!-- 可以自定義servlet.xml配置文件的位置和名稱，默認為WEB-INF目錄下，名稱為[<servlet-name>]-servlet.xml，如spring-servlet.xml-->
             <init-param>
                <param-name>contextConfigLocation</param-name>
                <param-value>/WEB-INF/spring-servlet.xml</param-value>
            </init-param> 
    
        <load-on-startup>1</load-on-startup>
    </servlet>
    
    <servlet-mapping>
        <servlet-name>spring</servlet-name>
        <!-- mvc-攔截所有的請求 -->
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    
</web-app>

根據上面的注釋我們知道要再相應的目錄下手動的新建一個spring-servlet.xml文件進行spring的配置信息

其次spring-servlet.xml的代碼如下：

<?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-3.0.xsd
        http://www.springframework.org/schema/context
        http://www.springframework.org/schema/context/spring-context-3.0.xsd">
        
        <!-- 激活注解的的標簽 -->
        <context:annotation-config/>
        
        <!-- 只搜索有controller注解的類，同時這個包名別搞錯了，不然就找不到controller -->
   　　 <context:component-scan base-package="cn.taofu" >
       　　 <context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>
   　　 </context:component-scan>
    
    　　<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        　　<property name="viewClass" value="org.springframework.web.servlet.view.JstlView" />
        　　<property name="prefix" value="/WEB-INF/jsps/" /><!-- 這個是配置在當下目錄尋找jsp文件-->
       　　 <property name="suffix" value=".jsp" />
   　　 </bean>
</beans>

配置好了web.xml和spring-servlet.xml，基本的spring的運行環境就有了，接下來就要生成一個測試controller

package cn.taofu;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("/test")
public class TestController {
    
    @RequestMapping("/mvc")
    public String getMode(){
        
        System.out.println("hello springmvc");
        
        return "index";
    }
}

好吧，這是最簡單的應用了，只要在相應的目錄下生成index.jsp文件。當請求訪問該方法上的mvc連接時就會跳轉到index.jsp,訪問的鏈接如：localhost:8080/springMvc/test/mvc ->回車。基本就能調通這個前後

代碼雖然入門初級，運行起來了我也是掉了塊肉了。當然其中的問題也不少。

問題一、在啟動服務器出現的報錯信息

java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1678)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1523)
    at org.apache.catalina.core.DefaultInstanceManager.loadClass(DefaultInstanceManager.java:525)
    at org.apache.catalina.core.DefaultInstanceManager.loadClassMaybePrivileged(DefaultInstanceManager.java:507)
    at org.apache.catalina.core.DefaultInstanceManager.newInstance(DefaultInstanceManager.java:126)
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1099)
    at org.apache.catalina.core.StandardWrapper.load(StandardWrapper.java:1043)
    at org.apache.catalina.core.StandardContext.loadOnStartup(StandardContext.java:4957)
    at org.apache.catalina.core.StandardContext$3.call(StandardContext.java:5284)
    at org.apache.catalina.core.StandardContext$3.call(StandardContext.java:5279)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)

　　這種錯誤很郁悶，單憑初級的開發是很難確定是什麼問題，所有只有去到頂級程序員的家棧溢出，發現如下解決辦法：

　　這個方法標注了，只有maven構建的應用，如不是還是多去google吧

You need to add the "Maven Dependency" in the Deployment Assembly

   - right click on your project and choose properties.
   - click  on Deployment Assembly.
   - click add
   - click on "Java Build Path Entries"
   - select Maven Dependencies"
   - click Finish.

Rebuild and deploy again

Note: This is also applicable for *non maven* project.

問題二、少了兩個jar,

message Handler processing failed; nested exception is java.lang.NoClassDefFoundError: javax/servlet/jsp/jstl/core/Config

description The server encountered an internal error that prevented it from fulfilling this request.

exception

org.springframework.web.util.NestedServletException: Handler processing failed; nested exception is java.lang.NoClassDefFoundError: javax/servlet/jsp/jstl/core/Config
	org.springframework.web.servlet.DispatcherServlet.triggerAfterCompletionWithError(DispatcherServlet.java:1259)
	org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:945)
	org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
	org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
	org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
root cause

java.lang.NoClassDefFoundError: javax/servlet/jsp/jstl/core/Config
	org.springframework.web.servlet.support.JstlUtils.exposeLocalizationContext(JstlUtils.java:97)
	org.springframework.web.servlet.view.JstlView.exposeHelpers(JstlView.java:135)
	org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:211)
	org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:263)
	org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1208)
	org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:992)
	org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:939)
	org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
	org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
	org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:827)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:622)
	org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
	org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)

　　這種錯誤比較好找，百度一下發現需要兩個jar.於是導入如下文件解決