手写SpringMVC框架（一）-------项目搭建

SpringMVC处理请求的大致流程： 我们来开始着手手写一个SpringMVC框架。

新建一个springMVC项目，流程参见 SpringMVC框架搭建流程

引入servlet相关的jar包：

<dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>3.1.0</version> </dependency>

新建一个servlet: 模拟springmvc，起名为LgDispatcherServlet

package com.lagou.edu.mvcframework.servlet; import javax.servlet.http.HttpServlet; /** * @author liuyj * @Title: LgDispatcherServlet * @create 2020-06-11 14:22 * @ProjectName springmvc-demo * @Description: TODO */ public class LgDispatcherServlet extends HttpServlet { }

web.xml中注册我们新建的LgDispatcherServlet：

<servlet> <servlet-name>lgmvc</servlet-name> <servlet-class>com.lagou.edu.mvcframework.servlet.LgDispatcherServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>lgmvc</servlet-name> <url-pattern>/*</url-pattern> </servlet-mapping>

新建几个自定义注解：

@Documented @Target(ElementType.FIELD) @Retention(RetentionPolicy.RUNTIME) public @interface LagouAutowired { String value() default ""; } @Documented @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) public @interface LagouController { String value() default ""; } @Documented @Target({ElementType.TYPE,ElementType.METHOD}) @Retention(RetentionPolicy.RUNTIME) public @interface LagouRequestMapping { String value() default ""; } @Documented @Target(ElementType.TYPE) @Retention(RetentionPolicy.RUNTIME) public @interface LagouService { String value() default ""; }

新建demo包下的service及implement实现类及controller并加上相应的注解： service:

package com.lagou.edu.demo.service; public interface IDemoService { String get(String name); }

impl:

package com.lagou.edu.demo.service.impl; import com.lagou.edu.demo.service.IDemoService; import com.lagou.edu.mvcframework.annotations.LagouService; @LagouService("demoService") public class DemoServiceImpl implements IDemoService { @Override public String get(String name) { System.out.println("service 实现类中的name参数：" + name) ; return name; } }

controller:

package com.lagou.edu.demo.controller; import com.lagou.edu.demo.service.IDemoService; import com.lagou.edu.mvcframework.annotations.LagouAutowired; import com.lagou.edu.mvcframework.annotations.LagouController; import com.lagou.edu.mvcframework.annotations.LagouRequestMapping; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; @LagouController @LagouRequestMapping("/demo") public class DemoController { @LagouAutowired private IDemoService demoService; /** * URL: /demo/query?name=lisi * @param request * @param response * @param name * @return */ @LagouRequestMapping("/query") public String query(HttpServletRequest request, HttpServletResponse response,String name) { return demoService.get(name); } }

本节到此结束。 下一节我们来开始结构开发设计。

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