java之Maven配置和springMvc的简单应用
初始springMvc这个框架，非常的陌生，而且幸好公司是通过maven这个代码管理工具，可以随时添加依赖。解决了很多问题在以后深入开发中。
项目结构：
通过结构中，pom.xml这个文件其实就说明这个项目是通过maven构建的，pom.xml里是主要负责构建jar或者war的依赖。其代码如下：
<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>
从中可以看出，如果要设置依赖jar，那么就要知道jar的相关信息。如何得知呢....
寻师问友后，得到了一个站点http://mvnrepository.com/，搜索你要的那个依赖，里面有相应的版本。
关于springMvc和maven的配置就上面的pom.xml，当然还可以配置Mybxxxs，hibernate..
接下来就要应用springmvc 的相关配置了：
首先配置的是 项目中的web.xml，其代码如下：
<?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> <!-- 可以自定义servlet.xml配置文件的位置和名称，默认为WEB-INF目录下，名称为[<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-拦截所有的请求 --> <url-pattern>/</url-pattern> </servlet-mapping> </web-app>
根据上面的注释我们知道要再相应的目录下手动的新建一个spring-servlet.xml文件进行spring的配置信息
其次spring-servlet.xml的代码如下：
<?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"> <!-- 激活注解的的标签 --> <context:annotation-config/> <!-- 只搜索有controller注解的类，同时这个包名别搞错了，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/" /><!-- 这个是配置在当下目录寻找jsp文件--> <property name="suffix" value=".jsp" /> </bean> </beans>
配置好了web.xml和spring-servlet.xml，基本的spring的运行环境就有了，接下来就要生成一个测试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，这是最简单的应用了，只要在相应的目录下生成index.jsp文件。当请求访问该方法上的mvc连接时就会跳转到index.jsp,访问的链接如：localhost:8080/springMvc/test/mvc ->回车。基本就能调通这个前后
代码虽然入门初级，运行起来了我也是掉了块肉了。当然其中的问题也不少。
问题一、在启动服务器出现的报错信息
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)
这种错误很郁闷，单凭初级的开发是很难确定是什么问题，所有只有去到顶级程序员的家栈溢出，发现如下解决办法：
这个方法标注了，只有maven构建的应用，如不是还是多去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.
问题二、少了两个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)
这种错误比较好找，百度一下发现需要两个jar.于是导入如下文件解决
过程是很艰难的，但结果还是可以的。努力
