Can you believe it? It took me only two days to develop a management system

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Difficulty analysis

Although, when I heard the news , I'm still shocked , After all, it is a complete management system , The function interface should not be too simple . And from the database design to the delivery of the whole system is completed by one person , The challenge effect will directly fill ！ But calm down and think , It's not that hard , The overall project process is ： Design ——> file ——> code ——> deliver .

After the overall process is clarified , Start to realize from scratch step by step , I didn't expect the last step , I only spent a day and a half ！！ Later, it took half a day to optimize the overall project ！

Project review

Final effect demonstration ：

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Technology selection ：

• SpringBoot

• Thymeleaf

• Mybatis-Plus

• MySQL

• PageHelper

• Lombok

• Redis（ Later page optimization ）

Project business process introduction

Login module 、 User module management and user role assignment , Management of news announcement module 、 Commodity module （ Including goods 、 Classification of goods 、 Order ） Management of 、 Management of role module ; Whether the front-end resource has permission to operate the resource , It uses thymeleaf Template syntax for judgment and identification, file upload and other basic functions .

Project structures, ( Using a template engine )

1. First create Maven project

Introduce corresponding dependencies , Build the required file directory

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2. To write yaml The configuration file

server:  
  port: 8080  
  
spring:  
  datasource:  
    driver-class-name: com.mysql.cj.jdbc.Driver  
    url: jdbc:mysql://localhost:3306/supplier?useUnicode=true&characterEncoding=utf8&serverTimezone=GMT%2B8  
    username: root  
    password: root  
  # thymeleaf  To configure   
  thymeleaf:  
    #  Turn off caching   
    cache: false  
    prefix: classpath:/templates/  
  
mybatis-plus:  
  mapper-locations: classpath*:/mapper/**/*.xml

3. The initial stage of the project is basically built

At the beginning of building a project , In order to make the system appear more standardized , I usually make the basic configuration and declaration in advance , The technologies involved in a project from the beginning and some basic configurations corresponding to these technologies , We should plan clearly in advance （ Personal habits ）. such as ： exception handling 、 Interceptor 、 filter 、 Constant classes, etc .

① exception handling

@ControllerAdvice  
public class ExceptionHandler {  
  
    private final org.slf4j.Logger logger = LoggerFactory.getLogger(this.getClass());  
  
    @org.springframework.web.bind.annotation.ExceptionHandler(Exception.class)  
    public ModelAndView exception(HttpServletRequest request, Exception e ) throws Exception {  
        logger.error("Request URL:{},Exception:{}",request.getRequestURL(),e);  
  
        if (AnnotationUtils.findAnnotation(e.getClass(), ResponseStatus.class )!= null){  
            throw e;  
        }  
  
        ModelAndView mv = new ModelAndView();  
        mv.addObject("url",request.getRequestURL());  
        mv.addObject("exception",e);  
        mv.setViewName("error/error");  
  
        return mv;  
    }  
}

② Interceptor

Interceptors are mainly used to process some resources , Similar to some resources that require users to log in before they can access , Some are not needed , such as ： The login function does not need to be blocked , The various management of users need to add interception operations , Only in this way can the security of the system be improved .

Login blocking

public class LoginInterceptor extends HandlerInterceptorAdapter {  
  
    @Override  
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {  
        if (request.getSession().getAttribute("user") == null){  
            response.sendRedirect("/api");  
            return false;  
        }  
        return true;  
    }  
}

Resource release

@Configuration  
public class WebConfig extends WebMvcConfigurerAdapter {  
  
    @Override  
    public void addInterceptors(InterceptorRegistry registry) {  
        registry.addInterceptor(new LoginInterceptor())  
                .addPathPatterns("/api/**")  
                .excludePathPatterns("/api","/api/doLogin");  
    }  
}

4. To write Controller Front end controller code

First create a FileController class

① Jump to the page of file upload

// Jump to the page of file upload   
@RequestMapping("/file-upload")  
public String userList(){  
  return "file-upload";  
}

② Realize the function of file upload

@RequestMapping("/doAddForUser")  
public String doAdd(User user, @RequestParam("file") MultipartFile files, HttpServletRequest request) throws IOException {  
  //String path = null;  
  if (files != null && !files.isEmpty()){  
    String name = UUID.randomUUID().toString().replace("-","");  
    // Get the extension of the file   
    String ext = FilenameUtils.getExtension(files.getOriginalFilename());  
    // Set the path of file upload   
    String url =request.getSession().getServletContext().getRealPath("/upload/");  
  
    File file = new File(url);  
    if (!file.exists()){  
      file.mkdir();  
    }  
    // Test path   
    System.out.println(request.getServletPath()+ "/upload");  
    System.out.println(request.getContextPath() + "/upload/");  
    // Save the renamed file in an absolute path   
    files.transferTo(new File(url+"/"+name+"."+ext));  
    user.setAvatar(request.getContextPath() + "/upload/"+name+"."+ext);  
  }  
  
  user.setId(UUID.randomUUID().toString());  
  String salt = PasswordUtils.getSalt();  
  String password = user.getPassword();  
  String encode = PasswordUtils.encode(password, salt);  
  user.setSalt(salt) ;  
  user.setPassword(encode);  
  user.setCreateTime(new Date());  
  userService.save(user);  
  return "redirect:/api/users";  
}

notes ： How to upload multiple files? The changes are as follows ：

③ Realize multi file upload function

In this project, the multi file upload function is not realized

private void commons(Object obj, @RequestParam("file") CommonsMultipartFile[] files, HttpServletRequest request) throws IOException {  
    //String path = null;  
    for (int i = 0; i < files.length; i++) {  
  
        if (files[i] != null && !files[i].isEmpty()){  
            String name = UUID.randomUUID().toString().replace("-","");  
            // Get the extension of the file   
            String ext = FilenameUtils.getExtension(files[i].getOriginalFilename());  
            // Set the path of file upload   
            String url =request.getSession().getServletContext().getRealPath("/upload/");  
  
            File file = new File(url);  
            if (!file.exists()){  
                file.mkdir();  
            }  
            // Test path   
            System.out.println(request.getServletPath()+ "/upload");  
            System.out.println(request.getContextPath() + "/upload/");  
            // Save the renamed file in an absolute path   
            files[i].transferTo(new File(url+"/"+name+"."+ext));  
  
            if (i == 0){  
                obj.setUrl1(request.getContextPath() + "/upload/"+name+"."+ext);  
            }  
            if (i == 1){  
                obj.setUrl2(request.getContextPath() + "/upload/"+name+"."+ext);  
            }  
            if (i == 2){  
                obj.setUrl3(request.getContextPath() + "/upload/"+name+"."+ext);  
            }  
            if (i == 3){  
                obj.setUrl4(request.getContextPath() + "/upload/"+name+"."+ext);  
            }  
            if (i == 4){  
                obj.setUrl5(request.getContextPath() + "/upload/"+name+"."+ext);  
            }  
        }  
    }  
}

5. Project optimization

For items where the front and rear ends are not separated , Most use page cache optimization , When the system suffers huge flow at a moment , When the first user accesses a page, the page data can be cached , such , Later, the pages visited by users are obtained from the cache , This reduces Operation on Database , Reduced the pressure on the database , So as to achieve optimal processing .

① Import dependence

<!--Redis-->  
<dependency>  
  <groupId>org.springframework.boot</groupId>  
  <artifactId>spring-boot-starter-data-redis</artifactId>  
</dependency>  
<!--commons-pools2  Object pool dependency -->  
<dependency>  
  <groupId>org.apache.commons</groupId>  
  <artifactId>commons-pool2</artifactId>  
</dependency>

② yaml To configure

## Redis To configure   
  redis:  
    #  Server address   
    host: localhost  
    #  port   
    port: 6379  
    #  database   
    database: 0  
    #  Timeout time   
    connect-timeout: 10000ms  
    lettuce:  
      pool:  
        #  maximum connection   
        max-active: 8  
        #  Maximum connection blocking wait time   Default  -1  
        max-wait: 10000ms  
        #  Maximum free time   Default 8  
        max-idle: 200  
        #  Minimum free connection   Default 8  
        min-idle: 5

④ Redis Serialization

@Configuration  
public class RedisConfig {  
  
    @Bean  
    public RedisTemplate<String,Object>  redisTemplate(RedisConnectionFactory redisConnectionFactory){  
        RedisTemplate<String,Object> redisTemplate = new RedisTemplate<>();  
        //key serialize   
        redisTemplate.setKeySerializer(new StringRedisSerializer());  
        //value serialize   
        redisTemplate.setValueSerializer(new GenericJackson2JsonRedisSerializer());  
        //hash type key Serialization   
        redisTemplate.setHashKeySerializer(new StringRedisSerializer());  
        //hash type value Serialization   
        redisTemplate.setHashValueSerializer(new GenericJackson2JsonRedisSerializer());  
        redisTemplate.setConnectionFactory(redisConnectionFactory);  
        return redisTemplate;  
    }  
}

③ Optimize processing

@Autowired  
private NewsService newsService;  
@Autowired  
private RedisTemplate redisTemplate;  
@Autowired  
private ThymeleafViewResolver viewResolver;  

@RequestMapping(value = "/news",produces = "text/html;charset=utf-8")  
@ResponseBody  
public String roles(Model model, @RequestParam(value = "pageNo",defaultValue = "1")Integer pageNo  
        , @RequestParam(value = "pageSize",defaultValue = "10")Integer pageSize  
        , HttpServletRequest request, HttpServletResponse response){  
//Redis Get page , If it's not empty , Then go back to the page   
    ValueOperations valueOperations = redisTemplate.opsForValue();  
    String html = (String) valueOperations.get("news-list");  
    if (!StringUtils.isEmpty(html)){  
        return html;  
    }  
    PageHelper.startPage(pageNo,pageSize);  
    List<News> list = newsService.list();  
    PageInfo<News> pageInfo = new PageInfo<>(list);  
    model.addAttribute("news",list);  
    model.addAttribute("pageInfo",pageInfo);  
   // If it is empty , Manual rendering , Deposit in Redis And in return   
    WebContext context = new WebContext(request, response, request.getServletContext(), request.getLocale(), model.asMap());  
    html = viewResolver.getTemplateEngine().process("news-list", context);  
    if (!StringUtils.isEmpty(html)){  
       // Set the expiration time for the cache   
        valueOperations.set("news-list",html,60, TimeUnit.SECONDS);  
    }  
    return html;  
}

④ Redis see

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6. matters needing attention

Be careful @Controller and @RestController The difference between , This project uses the template to render the page , and @Controller Is used to respond to the page ; and @RestController It's used to return to Json

In the project optimization stage, you need to add notes on the method @ResponseBody, Because we cache the whole page , So convert the page into JSON For storage .

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Inject Thymeleaf Parser , Will be specific The page is parsed into Json String to store

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Will deposit Redis Data in plus expiration time , Because the data in the page should be consistent with the database , If the user sees the data tens of seconds or a minute ago, it is still barely acceptable .

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At present, the code has been synchronized to Gitee：

https://gitee.com/gao-wumao/supplier

If necessary, go to the warehouse and pick it up by yourself , Please don't be stingy with the three companies in your hands ！

source ：https://blog.csdn.net/Gaowumao

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