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SpringMVC项目请求(请求映射路径)

news 来源：原创 2024/11/27 21:40:13

SpringMVC是web层的框架，主要的作用是接收请求、接收数据、响应结果，分成四部分内容:

请求映射路径
请求参数
日期类型参数传递
响应json数据

本次介绍的是设置请求映射路径。

1. 环境准备

创建一个Web的Maven项目

pom.xml添加Spring依赖

<?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.dcxuexi</groupId>
  <artifactId>springmvc_03_request_mapping</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>springmvc_03_request_mapping Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>5.2.15.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>3.1.0</version>
      <scope>provided</scope>
    </dependency>

  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.1</version>
        <configuration>
          <port>80</port>
          <path>springmvc</path>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

创建对应的配置类SpringMvcConfig和ServletContainersInitConfig

@Configuration
@ComponentScan("com.dcxuexi.controller")
public class SpringMvcConfig {
}

public class ServletContainersInitConfig extends AbstractAnnotationConfigDispatcherServletInitializer {
    @Override
    protected Class<?>[] getRootConfigClasses() {
        return new Class[]{SpringMvcConfig.class};
    }

    @Override
    protected Class<?>[] getServletConfigClasses() {
        return new Class[0];
    }

    @Override
    protected String[] getServletMappings() {
        return new String[]{"/"};
    }
}

编写UserController和CityController

@Controller
public class UserController {

    @RequestMapping("/select")
    @ResponseBody
    public String select(){
        System.out.println("UserController select ,running .....");
        return "{\"username\":\"xiaochuang\"}";
    }

    @RequestMapping("/delete")
    @ResponseBody
    public String delele(){
        System.out.println("UserController delele ,running .....");
        return "user xiaochuang is deleted.";
    }
}

@Controller
public class CityController {

    @RequestMapping("/select")
    @ResponseBody
    public String select(){
        System.out.println("CityController select ,running .....");
        return "{\"cityName\":\"shanghai\"}";
    }

    @RequestMapping("/delete")
    @ResponseBody
    public String delele(){
        System.out.println("CityController delele ,running .....");
        return "city shanghai is deleted.";
    }
}

最终创建好的项目结构如下:

在这里插入图片描述

把环境准备好后，启动Tomcat服务器，后台会报错:

在这里插入图片描述

从错误信息可以看出:

UserController有一个select方法，访问路径为http://localhost/springmvc/select
CityController也有一个select方法，访问路径为http://localhost/springmvc/select
当访问http://localhost/springmvc/select的时候，到底是访问UserController还是CityController?

2. 问题分析

团队多人开发，每人设置不同的请求路径，冲突问题该如何解决?

解决思路:为不同模块设置模块名作为请求路径前置

对于UserController模块的select,将其访问路径设置http://localhost/springmvc/user/select

对于CityController模块的select,将其访问路径设置http://localhost/springmvc/city/select

这样在同一个模块中出现命名冲突的情况就比较少了。

3. 设置映射路径

步骤1:修改Controller

@Controller
public class UserController {

    @RequestMapping("/user/select")
    @ResponseBody
    public String select(){
        System.out.println("UserController select ,running .....");
        return "{\"username\":\"xiaochuang\"}";
    }

    @RequestMapping("/user/delete")
    @ResponseBody
    public String delele(){
        System.out.println("UserController delele ,running .....");
        return "user xiaochuang is deleted.";
    }
}

@Controller
public class CityController {

    @RequestMapping("/city/select")
    @ResponseBody
    public String select(){
        System.out.println("CityController select ,running .....");
        return "{\"cityName\":\"shanghai\"}";
    }

    @RequestMapping("/city/delete")
    @ResponseBody
    public String delele(){
        System.out.println("CityController delele ,running .....");
        return "city shanghai is deleted.";
    }
}

启动Tomcat服务器:

在这里插入图片描述

问题是解决了，但是每个方法前面都需要进行修改，写起来比较麻烦而且还有很多重复代码，如果/user后期发生变化，所有的方法都需要改，耦合度太高。

步骤2:优化路径配置

优化方案:

@Controller
@RequestMapping("/user")
public class UserController {

    @RequestMapping("/select")
    @ResponseBody
    public String select(){
        System.out.println("UserController select ,running .....");
        return "{\"username\":\"xiaochuang\"}";
    }

    @RequestMapping("/delete")
    @ResponseBody
    public String delele(){
        System.out.println("UserController delele ,running .....");
        return "user xiaochuang is deleted.";
    }
}

@Controller
@RequestMapping("/city")
public class CityController {

    @RequestMapping("/select")
    @ResponseBody
    public String select(){
        System.out.println("CityController select ,running .....");
        return "{\"cityName\":\"shanghai\"}";
    }

    @RequestMapping("/delete")
    @ResponseBody
    public String delele(){
        System.out.println("CityController delele ,running .....");
        return "city shanghai is deleted.";
    }
}