springmvc项目,浏览器报404错误的问题

问题描述:

建立了web工程,配置pom.xml,web.xml,编写controller类,在spring-mvc-servlet.xml文件中指定开启注解和扫描的包位置 <mvc:annotation-driven /> <context:component-scan base-package="controller" />.打开tomcat,在浏览器中访问,提示404错误

问题分析:

一. 确定配置文件是否配置正确(springmvc的配置文件,web.xml和pom.xml基本不会配置出错)

因为提示的是404错误,可以确定正确加载了配置文件,处于排查需要,还是检查了配置文件的配置问题.
a) 放在WEB-INF/文件夹下,名称为spring-mvc-servlet.xml,不需要在web.xml中配置,系统自动读取
b) 放在WEB-INF/文件夹下,名称为自定义,或者放在src/main/resource文件夹下,需要在web.xml中配置,
配置代码如下:

	<servlet>  
		<servlet-name>dispatch</servlet>  
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>  
		<init-param>  
			<param-name>contextConfigLocation</param-name>  
			<param-value>/WEB-INF/applicationContext.xml</param-value>  
		</init-param>  
	</servlet>  
	<servlet-mapping>  
		<servlet-name>dispatch</servlet-name>  
		<servlet-pattern>*.*</servlet-pattern>  
	</servlet-mapping>  

二. 确定maven 依赖正确配置
a) 一般使用两个依赖就能使用注解配置springmvc项目,并能正常运行
pom中的依赖如下:

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<spring.version>4.2.6.RELEASE</spring.version>
		<hibernate.version>4.3.8.Final</hibernate.version>
	</properties>
	<dependencies>
		<dependency>
		  <groupId>junit</groupId>
		  <artifactId>junit</artifactId>
		  <version>3.8.1</version>
		  <scope>test</scope>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-web</artifactId>
			<version>${spring.version}</version>
		</dependency>
  </dependencies>

b) 我使用spring+springmvc+hibernate的搭配,pom依赖如下:

	<properties>
		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
		<spring.version>4.2.6.RELEASE</spring.version>
		<hibernate.version>4.3.8.Final</hibernate.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>3.8.1</version>
			<scope>test</scope>
		</dependency>

		<!-- springframework 4 dependencies begin -->
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-core</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-context</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-web</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-webmvc</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-orm</artifactId>
			<version>${spring.version}</version>
		</dependency>
		<!-- springframework 4 dependencies end -->

		<!-- log -->
		<dependency>
			<groupId>org.projectlombok</groupId>
			<artifactId>lombok</artifactId>
			<version>1.16.18</version>
			<scope>provided</scope>
		</dependency>

		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-api</artifactId>
			<version>1.7.7</version>
		</dependency>
		<dependency>
			<groupId>ch.qos.logback</groupId>
			<artifactId>logback-core</artifactId>
			<version>1.1.3</version>
		</dependency>
		<dependency>
			<groupId>ch.qos.logback</groupId>
			<artifactId>logback-classic</artifactId>
			<version>1.1.3</version>
		</dependency>
	</dependencies>

	<dependencyManagement>
		<dependencies>
			<!-- hibernate 配置 begin -->
			<dependency>
				<groupId>org.hibernate</groupId>
				<artifactId>hibernate-core</artifactId>
				<version>${hibernate.version}</version>
			</dependency>
			<dependency>
				<groupId>org.hibernate</groupId>
				<artifactId>hibernate-entitymanager</artifactId>
				<version>${hibernate.version}</version>
			</dependency>
			<dependency>
				<groupId>org.hibernate.common</groupId>
				<artifactId>hibernate-commons-annotations</artifactId>
				<version>4.0.5.Final</version>
			</dependency>
			<dependency>
				<groupId>org.hibernate.javax.persistence</groupId>
				<artifactId>hibernate-jpa-2.1-api</artifactId>
				<version>1.0.0.Final</version>
			</dependency>
			<dependency>
				<groupId>org.hibernate</groupId>
				<artifactId>hibernate-ehcache</artifactId>
				<version>${hibernate.version}</version>
				<!-- hibernate 配置 end -->
			</dependency>
			<!-- mysql数据库的驱动包 start -->
			<dependency>
				<groupId>mysql</groupId>
				<artifactId>mysql-connector-java</artifactId>
				<version>6.0.6</version>
			</dependency>
			<!-- 数据连接池 -->
			<dependency>
				<groupId>org.hibernate</groupId>
				<artifactId>hibernate-c3p0</artifactId>
				<version>${hibernate.version}</version>
			</dependency>
		</dependencies>
	</dependencyManagement>

我已经依赖了a中所说的两个包,但是不能在浏览器中访问,会报404错误.

解决办法:

看了很多spring mvc的maven依赖,发现有人使用如下依赖:

	 <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
		 <dependency>
			<groupId>javax.servlet</groupId>
			<artifactId>javax.servlet-api</artifactId>
			<version>3.1.0</version>
			<scope>provided</scope>
	    </dependency> 
	

我在b中的pom文件中加入这个依赖,就能正常访问了,不知道什么原因.(狗屁问题,浪费了我两个小时的时间,一度怀疑人生)