瑞吉外卖项目带资料——遇到的问题和解决方法，有用的知识点

目录

一、Pom依赖

二、 application.yml配置

三、filter过滤器实现强制登录

四、基于Mybatis-Plus的功能 

 五、文件的上传与下载

六、总结 

七、相关资源下载

一、Pom依赖

1.  
   <?xml version="1.0" encoding="UTF-8"?>
2.  
   <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
3.  
   xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
4.  
   <modelVersion>4.0.0</modelVersion>
5.  
   <parent>
6.  
   <groupId>org.springframework.boot</groupId>
7.  
   <artifactId>spring-boot-starter-parent</artifactId>
8.  
   <version>2.5.0</version>
9.  
   <relativePath/> <!-- lookup parent from repository -->
10.  
    </parent>
11.  
    <groupId>com.example</groupId>
12.  
    <artifactId>reggie</artifactId>
13.  
    <version>0.0.1-SNAPSHOT</version>
14.  
    <name>reggie</name>
15.  
    <description>reggie</description>
16.  
    <properties>
17.  
    <java.version>8</java.version>
18.  
    </properties>
19.  
    <dependencies>
20.  
    <dependency>
21.  
    <groupId>org.springframework.boot</groupId>
22.  
    <artifactId>spring-boot-starter-web</artifactId>
23.  
    </dependency>
24.  
    <dependency>
25.  
    <groupId>org.mybatis.spring.boot</groupId>
26.  
    <artifactId>mybatis-spring-boot-starter</artifactId>
27.  
    <version>3.0.0</version>
28.  
    </dependency>
29.  
     
30.  
    <dependency>
31.  
    <groupId>mysql</groupId>
32.  
    <artifactId>mysql-connector-java</artifactId>
33.  
    <scope>runtime</scope>
34.  
    </dependency>
35.  
    <dependency>
36.  
    <groupId>org.projectlombok</groupId>
37.  
    <artifactId>lombok</artifactId>
38.  
    <optional>true</optional>
39.  
    </dependency>
40.  
    <dependency>
41.  
    <groupId>org.springframework.boot</groupId>
42.  
    <artifactId>spring-boot-starter-test</artifactId>
43.  
    <scope>test</scope>
44.  
    </dependency>
45.  
    <dependency>
46.  
    <groupId>com.alibaba</groupId>
47.  
    <artifactId>fastjson</artifactId>
48.  
    <version>1.2.76</version>
49.  
    </dependency>
50.  
    <dependency>
51.  
    <groupId>com.alibaba</groupId>
52.  
    <artifactId>druid-spring-boot-starter</artifactId>
53.  
    <version>1.1.23</version>
54.  
    </dependency>
55.  
    <dependency>
56.  
    <groupId>com.baomidou</groupId>
57.  
    <artifactId>mybatis-plus-boot-starter</artifactId>
58.  
    <version>3.4.2</version>
59.  
    </dependency>
60.  
    <dependency>
61.  
    <groupId>commons-lang</groupId>
62.  
    <artifactId>commons-lang</artifactId>
63.  
    <version>2.6</version>
64.  
    </dependency>
65.  
    </dependencies>
66.  
     
67.  
    <build>
68.  
    <plugins>
69.  
    <plugin>
70.  
    <groupId>org.springframework.boot</groupId>
71.  
    <artifactId>spring-boot-maven-plugin</artifactId>
72.  
    <configuration>
73.  
    <excludes>
74.  
    <exclude>
75.  
    <groupId>org.projectlombok</groupId>
76.  
    <artifactId>lombok</artifactId>
77.  
    </exclude>
78.  
    </excludes>
79.  
    </configuration>
80.  
    </plugin>
81.  
    </plugins>
82.  
    </build>
83.  
     
84.  
    </project>

二、 application.yml配置

1.  
   server:
2.  
   port: 8080
3.  
   spring:
4.  
   application:
5.  
   name: reggie
6.  
   datasource:
7.  
   druid:
8.  
   driver-class-name: com.mysql.cj.jdbc.Driver
9.  
   url: jdbc:mysql://localhost:3306/reggie?serverTimezone=Asia/Shanghai&useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull&useSSL=false&allowPublicKeyRetrieval=true
10.  
    username: root
11.  
    password: 123456
12.  
    mybatis-plus:
13.  
    configuration:
14.  
    #在映射实体或者属性时，将数据库中表名和字段名中的下划线去掉，按照驼峰命名法映射
15.  
    map-underscore-to-camel-case: true
16.  
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
17.  
    global-config:
18.  
    db-config:
19.  
    id-type: ASSIGN_ID
20.  
    reggie:
21.  
    path: E:\pic\
22.  
    #图片保存与下载位置

三、filter过滤器实现强制登录

• 防止用户没有登录就能直接访问到其他页面

• LoginCheckFilter类

1.  
   @WebFilter(filterName = "loginCheckFilter",urlPatterns = "/*")
2.  
   @Slf4j
3.  
   public class LoginCheckFilter implements Filter{
4.  
   //路径匹配器，支持通配符
5.  
   public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();
6.  
    
7.  
   @Override
8.  
   public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
9.  
   HttpServletRequest request = (HttpServletRequest) servletRequest;
10.  
    HttpServletResponse response = (HttpServletResponse) servletResponse;
11.  
     
12.  
    //1、获取本次请求的URI
13.  
    String requestURI = request.getRequestURI();// /backend/index.html
14.  
     
15.  
    log.info("拦截到请求：{}",requestURI);
16.  
     
17.  
    //定义不需要处理的请求路径
18.  
    String[] urls = new String[]{
19.  
    "/employee/login",
20.  
    "/employee/logout",
21.  
    "/backend/**",
22.  
    "/front/**",
23.  
    "/common/**",
24.  
    "/user/sendMsg",
25.  
    "/user/login"
26.  
    };
27.  
     
28.  
    //2、判断本次请求是否需要处理
29.  
    boolean check = check(urls, requestURI);
30.  
     
31.  
    //3、如果不需要处理，则直接放行
32.  
    if(check){
33.  
    log.info("本次请求{}不需要处理",requestURI);
34.  
    filterChain.doFilter(request,response);
35.  
    return;
36.  
    }
37.  
     
38.  
    //4-1、判断登录状态，如果已登录，则直接放行
39.  
    if(request.getSession().getAttribute("employee") != null){
40.  
    log.info("用户已登录，用户id为：{}",request.getSession().getAttribute("employee"));
41.  
     
42.  
    Long empId = (Long) request.getSession().getAttribute("employee");
43.  
    BaseContext.setCurrentId(empId);
44.  
     
45.  
    filterChain.doFilter(request,response);
46.  
    return;
47.  
    }
48.  
     
49.  
    //4-2、判断登录状态，如果已登录，则直接放行
50.  
    if(request.getSession().getAttribute("user") != null){
51.  
    log.info("用户已登录，用户id为：{}",request.getSession().getAttribute("user"));
52.  
     
53.  
    Long userId = (Long) request.getSession().getAttribute("user");
54.  
    BaseContext.setCurrentId(userId);
55.  
     
56.  
    filterChain.doFilter(request,response);
57.  
    return;
58.  
    }
59.  
     
60.  
    log.info("用户未登录");
61.  
    //5、如果未登录则返回未登录结果，通过输出流方式向客户端页面响应数据
62.  
    response.getWriter().write(JSON.toJSONString(R.error("NOTLOGIN")));
63.  
    return;
64.  
     
65.  
    }
66.  
     
67.  
    /**
68.  
    * 路径匹配，检查本次请求是否需要放行
69.  
    * @param urls
70.  
    * @param requestURI
71.  
    * @return
72.  
    */
73.  
    public boolean check(String[] urls,String requestURI){
74.  
    for (String url : urls) {
75.  
    boolean match = PATH_MATCHER.match(url, requestURI);
76.  
    if(match){
77.  
    return true;
78.  
    }
79.  
    }
80.  
    return false;
81.  
    }
82.  
    }

• BaseContext类

1.  
   /**
2.  
   * 基于ThreadLocal封装工具类，用户保存和获取当前登录用户id
3.  
   */
4.  
   public class BaseContext {
5.  
   private static ThreadLocal<Long> threadLocal = new ThreadLocal<>();
6.  
    
7.  
   /**
8.  
   * 设置值
9.  
   * @param id
10.  
    */
11.  
    public static void setCurrentId(Long id){
12.  
    threadLocal.set(id);
13.  
    }
14.  
     
15.  
    /**
16.  
    * 获取值
17.  
    * @return
18.  
    */
19.  
    public static Long getCurrentId(){
20.  
    return threadLocal.get();
21.  
    }
22.  
    }

• 注意要在SpringBootApplication上加

  @ServletComponentScan

• 注解后可以直接通过  @WebFilter注解自动注册

四、基于Mybatis-Plus的功能 

• 分页功能例子

1.  
   /**
2.  
   * 员工信息分页查询
3.  
   * @param page
4.  
   * @param pageSize
5.  
   * @param name
6.  
   * @return
7.  
   */
8.  
   @GetMapping("/page")
9.  
   public R<Page> page(int page, int pageSize, String name){
10.  
    log.info("page = {},pageSize = {},name = {}" ,page,pageSize,name);
11.  
     
12.  
    //构造分页构造器
13.  
    Page pageInfo = new Page(page,pageSize);
14.  
     
15.  
    //构造条件构造器
16.  
    LambdaQueryWrapper<Employee> queryWrapper = new LambdaQueryWrapper();
17.  
    //添加过滤条件
18.  
    queryWrapper.like(StringUtils.isNotEmpty(name),Employee::getName,name);
19.  
    //添加排序条件
20.  
    queryWrapper.orderByDesc(Employee::getUpdateTime);
21.  
     
22.  
    //执行查询
23.  
    employeeService.page(pageInfo,queryWrapper);
24.  
     
25.  
    return R.success(pageInfo);
26.  
    }

•  Mybatis-Plus直接帮我们节省了写SQL语句的步骤，简单的增删改查直接service调用即可
• 复杂的SQL语句通过LambdaQueryWrapper来完成

 五、文件的上传与下载

1.  
   package com.xjj.controller;
2.  
    
3.  
   import com.xjj.common.R;
4.  
   import lombok.extern.slf4j.Slf4j;
5.  
   import org.springframework.beans.factory.annotation.Value;
6.  
   import org.springframework.web.bind.annotation.*;
7.  
   import org.springframework.web.multipart.MultipartFile;
8.  
    
9.  
   import javax.servlet.ServletOutputStream;
10.  
    import javax.servlet.http.HttpServletResponse;
11.  
    import java.io.File;
12.  
    import java.io.FileInputStream;
13.  
    import java.io.FileNotFoundException;
14.  
    import java.io.IOException;
15.  
    import java.util.UUID;
16.  
     
17.  
    /**
18.  
    * 文件上传和下载
19.  
    */
20.  
    @RestController
21.  
    @RequestMapping("/common")
22.  
    @Slf4j
23.  
    public class CommonController {
24.  
     
25.  
    @Value("${reggie.path}")
26.  
    private String basePath;
27.  
     
28.  
    /**
29.  
    * 文件上传
30.  
    * @param file
31.  
    * @return
32.  
    */
33.  
    @PostMapping("/upload")
34.  
    public R<String> upload(MultipartFile file){
35.  
    //file是一个临时文件，需要转存到指定位置，否则本次请求完成后临时文件会删除
36.  
    log.info(file.toString());
37.  
     
38.  
    //原始文件名
39.  
    String originalFilename = file.getOriginalFilename();//abc.jpg
40.  
    String suffix = originalFilename.substring(originalFilename.lastIndexOf("."));
41.  
     
42.  
    //使用UUID重新生成文件名，防止文件名称重复造成文件覆盖
43.  
    String fileName = UUID.randomUUID().toString() suffix;//dfsdfdfd.jpg
44.  
     
45.  
    //创建一个目录对象
46.  
    File dir = new File(basePath);
47.  
    //判断当前目录是否存在
48.  
    if(!dir.exists()){
49.  
    //目录不存在，需要创建
50.  
    dir.mkdirs();
51.  
    }
52.  
     
53.  
    try {
54.  
    //将临时文件转存到指定位置
55.  
    file.transferTo(new File(basePath fileName));
56.  
    } catch (IOException e) {
57.  
    e.printStackTrace();
58.  
    }
59.  
    return R.success(fileName);
60.  
    }
61.  
     
62.  
    /**
63.  
    * 文件下载
64.  
    * @param name
65.  
    * @param response
66.  
    */
67.  
    @GetMapping("/download")
68.  
    public void download(String name, HttpServletResponse response){
69.  
     
70.  
    try {
71.  
    //输入流，通过输入流读取文件内容
72.  
    FileInputStream fileInputStream = new FileInputStream(new File(basePath name));
73.  
     
74.  
    //输出流，通过输出流将文件写回浏览器
75.  
    ServletOutputStream outputStream = response.getOutputStream();
76.  
     
77.  
    response.setContentType("image/jpeg");
78.  
     
79.  
    int len = 0;
80.  
    byte[] bytes = new byte[1024];
81.  
    while ((len = fileInputStream.read(bytes)) != -1){
82.  
    outputStream.write(bytes,0,len);
83.  
    outputStream.flush();
84.  
    }
85.  
     
86.  
    //关闭资源
87.  
    outputStream.close();
88.  
    fileInputStream.close();
89.  
    } catch (Exception e) {
90.  
    e.printStackTrace();
91.  
    }
92.  
     
93.  
    }
94.  
    }

六、总结 

• 瑞吉项目总体来说难度不大，很适合入门的练手，巩固基础，更好的了解Spring框架 

七、相关资源下载

• 我的代码

•  黑马的资料

https://jianguo666.lanzoum.com/b02k437wj 密码:1234

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