手写SpringMVC框架（一）-------项目搭建

深藏阁楼爱情的钟 2023-02-22 08:18 54阅读 0赞

SpringMVC处理请求的大致流程：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lvbmdidXRpbmd4aWRl_size_16_color_FFFFFF_t_70]  
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][SpringMVC]

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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[SpringMVC]: https://blog.csdn.net/yongbutingxide/article/details/106770624