SpringMVC 中 Controller 前置控制器的 3 种实现方式

约定不等于承诺〃 2022-02-19 20:15 420阅读 0赞

### SpringMVC 中 Controller 前置控制器的 3 种实现方式 ###

### 一、实现步骤： ###

先看一下完整的项目结构：  
![20190413230051621.png][]

**①导入 jar 包**

![20190413220743239.png][]

**使用 maven 只需要：**

<dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-webmvc</artifactId>
 <version>5.1.6.RELEASE</version>
 </dependency>
 
 <dependency>
 <groupId>javax.servlet</groupId>
 <artifactId>javax.servlet-api</artifactId>
 <version>3.1.0</version>
 <scope>provided</scope>
 </dependency>

**②web.xml 配置核心控制器( DispatcherServlet )**

源代码：

<?xml version="1.0" encoding="utf-8"?>
 <web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
 http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
 	version="3.0" metadata-complete="false">
 
 	
 	<servlet>
 		<servlet-name>springmvc</servlet-name>
 		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
 		
 		<init-param>
 			<param-name>contextConfigLocation</param-name>
 			<param-value>classpath:springmvc.xml</param-value>
 		</init-param>
 		
 		<load-on-startup>1</load-on-startup>
 	</servlet>
 	<servlet-mapping>
 		<servlet-name>springmvc</servlet-name>
 		
 		<url-pattern>/</url-pattern>
 	</servlet-mapping>
 
 </web-app>

**③Controller控制器实现的 3 种方式** ( 使用方式3全注解，方式1和方式2了解即可！！！)

**方式1：实现 Controller 的接口**

package com.xiaopengwei.springmvc.controller;
 
 import org.springframework.web.servlet.ModelAndView;
 import org.springframework.web.servlet.mvc.Controller;
 
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 
 /** * * 创建 Controller 方法 1 * http://localhost:8080/test1 * * * @author Xiao pengwei * @since 2019-04-13 */
 public class ControllerMethod1 implements Controller { 
 
 @Override
 public ModelAndView handleRequest(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) throws Exception { 
 
 System.out.println("方式一：实现 Controller 接口");
 
 return null;
 }
 }

SpringMVC 配置：

<bean id="/test1" class="com.xiaopengwei.springmvc.controller.ControllerMethod1" ></bean>

**方式2：实现HttpRequestHandler接口**

package com.xiaopengwei.springmvc.controller;
 
 import org.springframework.web.HttpRequestHandler;
 
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
 
 /** * * 创建 Controller 方法 2 * http://localhost:8080/test2 * * * @author Xiao pengwei * @since 2019-04-13 */
 public class ControllerMethod2 implements HttpRequestHandler { 
 
 @Override
 public void handleRequest(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 
 
 System.out.println("方法二：实现HttpRequestHandler接口");
 
 }
 }

SpringMVC 配置：

<bean id="/test2" class="com.xiaopengwei.springmvc.controller.ControllerMethod2" ></bean>

**方式3：直接就是一个普通JAVA类 （使用注解的方式，注意：要配置全注解！！）**

package com.xiaopengwei.springmvc.controller;
 
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.RequestMapping;
 import org.springframework.web.bind.annotation.ResponseBody;
 
 /** * * 创建 Controller 方法 3 * http://localhost:8080/test3 * * * @author Xiao pengwei * @since 2019-04-13 */
 @Controller
 public class ControllerMethod3 { 
 
 //配置访问路径
 @RequestMapping("/test3")
 @ResponseBody
 public void testMethod3(){ 
 
 System.out.println("方式三：普通类 + 注解 Controller");
 
 }
 
 }

在 SpringMVC 的配置中添加自动扫描（作用：让spring管理这个bean即可，无需指定路径，在方法上面通过 @RequestMapping 指定即可！）

<context:component-scan base-package="com.xiaopengwei.springmvc.controller" />

最后我的整个 SpringMVC 配置：

<?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: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">
 
 
 <bean id="date" class="java.util.Date"></bean>
 
 
 <bean id="/test1" class="com.xiaopengwei.springmvc.controller.ControllerMethod1" ></bean>
 
 
 <bean id="/test2" class="com.xiaopengwei.springmvc.controller.ControllerMethod2" ></bean>
 
 
 
 <context:component-scan base-package="com.xiaopengwei.springmvc.controller" />
 
 </beans>

### 二、运行方式 ###

有两种方式可以运行：  
**方式一 使用 maven tomcat 插件：**  
（1）配置 pom 插件，为了方便，贴出整个 pom 供参考

<?xml version="1.0" encoding="UTF-8"?>
 
 <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/xsd/maven-4.0.0.xsd">
 <modelVersion>4.0.0</modelVersion>
 
 <groupId>com.xiaopengwei</groupId>
 <artifactId>springmvc-source-analysis</artifactId>
 <version>1.0.0</version>
 <packaging>war</packaging>
 
 <name>springmvc-analysis Maven Webapp</name>
 
 <url>http://www.example.com</url>
 
 <properties>
 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 <maven.compiler.source>1.7</maven.compiler.source>
 <maven.compiler.target>1.7</maven.compiler.target>
 <spring.webmvc.version>5.1.6.RELEASE</spring.webmvc.version>
 </properties>
 
 <dependencies>
 
 
 <dependency>
 <groupId>org.springframework</groupId>
 <artifactId>spring-webmvc</artifactId>
 <version>${spring.webmvc.version}</version>
 </dependency>
 
 
 <dependency>
 <groupId>javax.servlet</groupId>
 <artifactId>javax.servlet-api</artifactId>
 <version>3.1.0</version>
 <scope>provided</scope>
 </dependency>
 
 <dependency>
 <groupId>junit</groupId>
 <artifactId>junit</artifactId>
 <version>4.11</version>
 <scope>test</scope>
 </dependency>
 
 </dependencies>
 
 <build>
 <finalName>springmvc-analysis</finalName>
 <pluginManagement>
 <plugins>
 
 <plugin>
 <groupId>org.apache.tomcat.maven</groupId>
 <artifactId>tomcat7-maven-plugin</artifactId>
 <version>2.2</version>
 <configuration>
 <port>8080</port>
 <path>/</path>
 <uriEncoding>UTF-8</uriEncoding>
 <server>tomcat7</server>
 </configuration>
 </plugin>
 <plugin>
 <artifactId>maven-clean-plugin</artifactId>
 <version>3.1.0</version>
 </plugin>
 
 <plugin>
 <artifactId>maven-resources-plugin</artifactId>
 <version>3.0.2</version>
 </plugin>
 <plugin>
 <artifactId>maven-compiler-plugin</artifactId>
 <version>3.8.0</version>
 </plugin>
 <plugin>
 <artifactId>maven-surefire-plugin</artifactId>
 <version>2.22.1</version>
 </plugin>
 <plugin>
 <artifactId>maven-war-plugin</artifactId>
 <version>3.2.2</version>
 </plugin>
 <plugin>
 <artifactId>maven-install-plugin</artifactId>
 <version>2.5.2</version>
 </plugin>
 <plugin>
 <artifactId>maven-deploy-plugin</artifactId>
 <version>2.8.2</version>
 </plugin>
 </plugins>
 </pluginManagement>
 </build>
 </project>

（2）点击添加配置，选择 maven，输入命令：

tomcat7:run

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9pY29kZS5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70]

**方式二 使用本机 Tomcat：**  
（1）新建 Tomcat 配置

详细请参考：[https://blog.csdn.net/qq\_40147863/article/details/85771619][https_blog.csdn.net_qq_40147863_article_details_85771619]

### 三、运行结果 ###

*  测试三种方式
 *  [http://localhost:8080/test1][http_localhost_8080_test1]
 *  [http://localhost:8080/test2][http_localhost_8080_test2]
 *  [http://localhost:8080/test3][http_localhost_8080_test3]  
    ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9pY29kZS5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 1]

[20190413230051621.png]: /images/20220220/b4a3af2f219c4a138587d74639d59d41.png
[20190413220743239.png]: /images/20220220/d4db2a80cae647aab6877041e294f549.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9pY29kZS5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70]: /images/20220220/05eedce5bdc04fafafa402b45f14e250.png
[https_blog.csdn.net_qq_40147863_article_details_85771619]: https://blog.csdn.net/qq_40147863/article/details/85771619
[http_localhost_8080_test1]: http://localhost:8080/test1
[http_localhost_8080_test2]: http://localhost:8080/test2
[http_localhost_8080_test3]: http://localhost:8080/test3
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9pY29kZS5ibG9nLmNzZG4ubmV0_size_16_color_FFFFFF_t_70 1]: /images/20220220/f61969c671044e1ba94cc342c2e6632e.png