一:前言

这个就是用springboot实现后台管理(CRUD)的小demo,相比于SSM的配置地狱，springboot的自动配置确实很牛，tomcat都内置，我们想要修改相关的信息只要在yaml配置文件修改就行了，关于Dao层，这个mybatis-plus,quo实是很牛逼，这个连sql都是省略了,但也仅限于单表的sql,复杂的sql语句还得靠mapper.xml中进行书写。总之一句话，你不学SSM,springboot里面很多原理不理解，但是学了springboot,SSM配置起来是真麻烦。

二:用到的相关技术

spingboot(2.6.3)+Mybatis-Plus+Maven+thmeleaf+Mysql
环境是JDK1.8，maven是3.4.1，mysql5.7

三:实现功能流程

在springboot官方文档中找到对应的场景启动器（starter）
分析其–xxxautoConfigration
然后找到xxxxProperties绑定了配置文件有哪些。
哪些需要修改还是自定义

四:功能展示

1:登录首页

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2:主页面

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3:展示表单（select）

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4:删除一条记录（delete）

点击删除会自动删除，同时的话，在那页删除还会自动回到那页，这里就是点击删除发送这个请求的时候，把当前页的信息也给发送处理的请求的，所以请求里信息会被Controller层处理，处理完请求在把该页信息用到反应请求的路径上。
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5:修改一条记录（Update）

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修改页面:

6:增加一条记录信息（insert）

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五:上码

1:导入相关场景启动器

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>2.6.3</version><relativePath/> <!-- lookup parent from repository --></parent><groupId>com.wyj</groupId><artifactId>springboot-05-web02</artifactId><version>0.0.1-SNAPSHOT</version><name>springboot-05-web02</name><description>springboot-05-web02</description><properties><java.version>11</java.version><repackage.classifier/><spring-native.version>0.11.2</spring-native.version><kotlin.version>1.6.20-M1</kotlin.version></properties><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-thymeleaf</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!--导入jdbc的场景启动器--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-data-jdbc</artifactId></dependency><!--导入数据库的驱动包  因为我们不知道到底是哪个驱动器  mysql 还是其他的 --><!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java --><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.47</version></dependency><!--导入Mybatis-Plus的场景--><dependency><groupId>com.baomidou</groupId><artifactId>mybatis-plus-boot-starter</artifactId><version>3.5.1</version></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-devtools</artifactId><scope>runtime</scope><optional>true</optional></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-configuration-processor</artifactId><optional>true</optional></dependency><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><optional>true</optional></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency><dependency><groupId>org.jetbrains.kotlin</groupId><artifactId>kotlin-stdlib-jdk8</artifactId><version>${kotlin.version}</version></dependency><dependency><groupId>org.jetbrains.kotlin</groupId><artifactId>kotlin-test</artifactId><version>${kotlin.version}</version><scope>test</scope></dependency></dependencies><build><plugins><plugin><groupId>org.springframework.boot</groupId><artifactId>spring-boot-maven-plugin</artifactId><configuration><excludes><exclude><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></exclude></excludes><classifier>${repackage.classifier}</classifier><image><builder>paketobuildpacks/builder:tiny</builder><env><BP_NATIVE_IMAGE>true</BP_NATIVE_IMAGE></env></image></configuration></plugin><plugin><groupId>org.springframework.experimental</groupId><artifactId>spring-aot-maven-plugin</artifactId><version>${spring-native.version}</version><executions><execution><id>test-generate</id><goals><goal>test-generate</goal></goals></execution><execution><id>generate</id><goals><goal>generate</goal></goals></execution></executions></plugin><plugin><groupId>org.jetbrains.kotlin</groupId><artifactId>kotlin-maven-plugin</artifactId><version>${kotlin.version}</version><executions><execution><id>compile</id><phase>compile</phase><goals><goal>compile</goal></goals></execution><execution><id>test-compile</id><phase>test-compile</phase><goals><goal>test-compile</goal></goals></execution></executions><configuration><jvmTarget>1.8</jvmTarget></configuration></plugin><plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><executions><execution><id>compile</id><phase>compile</phase><goals><goal>compile</goal></goals></execution><execution><id>testCompile</id><phase>test-compile</phase><goals><goal>testCompile</goal></goals></execution></executions></plugin></plugins></build><repositories><repository><id>spring-releases</id><name>Spring Releases</name><url>https://repo.spring.io/release</url><snapshots><enabled>false</enabled></snapshots></repository></repositories><pluginRepositories><pluginRepository><id>spring-releases</id><name>Spring Releases</name><url>https://repo.spring.io/release</url><snapshots><enabled>false</enabled></snapshots></pluginRepository></pluginRepositories><profiles><profile><id>native</id><properties><repackage.classifier>exec</repackage.classifier><native-buildtools.version>0.9.9</native-buildtools.version></properties><dependencies><dependency><groupId>org.junit.platform</groupId><artifactId>junit-platform-launcher</artifactId><scope>test</scope></dependency></dependencies><build><plugins><plugin><groupId>org.graalvm.buildtools</groupId><artifactId>native-maven-plugin</artifactId><version>${native-buildtools.version}</version><extensions>true</extensions><executions><execution><id>test-native</id><phase>test</phase><goals><goal>test</goal></goals></execution><execution><id>build-native</id><phase>package</phase><goals><goal>build</goal></goals></execution></executions></plugin></plugins></build></profile></profiles></project>

2:yaml配置文件

spring:datasource:url: jdbc:mysql://localhost:3306/smbms?useSSL=trueusername: rootpassword: wyjdriver-class-name: com.mysql.jdbc.Driver#Mybatis-plus配置
mybatis-plus:#全局配置文件的路径config-location: classpath:mybatis/mybatis-config.xml#指明.xml文件的路径mapper-locations: classpath:mybatis/mapper/*.xml

3:Pojo

(1):admin

package com.wyj.Pojo;import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.ToString;@Data
@AllArgsConstructor
@NoArgsConstructor
@ToString
public class Admin {private String userName;private String passWord;
}

(2):User

package com.wyj.Pojo;import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;@Data
@AllArgsConstructor
@NoArgsConstructor
@TableName(value = "userTO")
public class User {//Mybatis-Plus的测试数据private Integer id;private String name;private Integer age;private String email;}

4:mapper

这里继承了BaseMapper,很多sql就不用写了，这里还需要注意的是，默认的表明是和类名一致的，如过类名和表名不一致的话，需要用注解@TableName 把表名注上

package com.wyj.mapper;import com.baomidou.mybatisplus.core.conditions.Wrapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.wyj.Pojo.User;
import org.apache.ibatis.annotations.Mapper;import java.io.Serializable;
import java.util.Collection;
import java.util.List;
import java.util.Map;@Mapper
public interface UserMapper extends BaseMapper<User> {}

5:Service层

(1)Service接口

package com.wyj.Service;import com.baomidou.mybatisplus.extension.service.IService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.wyj.Pojo.User;
import com.wyj.mapper.UserMapper;import java.util.List;public interface UserService extends IService<User>  {}

(2):Service的实现类

package com.wyj.Service.imp;import com.baomidou.mybatisplus.core.conditions.Wrapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.wyj.Pojo.User;
import com.wyj.Service.UserService;
import com.wyj.mapper.UserMapper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;@Service
public class UserServiceImp extends ServiceImpl<UserMapper,User> implements UserService {}

6:Controller层

(1):IndexController

package com.wyj.Controller;import com.wyj.Pojo.Admin;
import com.wyj.Pojo.TextUser;
import com.wyj.Pojo.User;
import com.wyj.Service.imp.TextUserServiceImp;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;import javax.servlet.http.HttpSession;@Controller
public class IndexController {//设置首页 只要请求是'/'或者是'/login'  我们就会返回首页@RequestMapping(value = {"/","/login"})public String loginPage() {return "login";}@RequestMapping("/let")public String loginPage(Admin admin, HttpSession session, Model model) {if ("wyj".equals(admin.getUserName()) && "123".equals(admin.getPassWord())) {session.setAttribute("loginUser",admin);return "redirect:main.html";//这里重定向的是一个请求所以得重新写一个}else{                            //一般我们return的是一个  html 页面//视图解析器自动给我们加上前缀和后缀model.addAttribute("msg","请输入正确的密码和用户名");return "login";}}@RequestMapping("/main.html")public String showPage() {return "main";}}

(2):TableController

package com.wyj.Controller;import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.wyj.Pojo.User;
import com.wyj.Service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.mvc.support.RedirectAttributes;import java.util.List;@Controller
public class TableController {@Autowiredprivate UserService userService;@GetMapping("/basic_table")public String basic_table() {return "table/basic_table";}@GetMapping("/dynamic_table")public String dynamic_table(@RequestParam(value = "pn",defaultValue = "1") Integer pn, Model model) {//List<User> list = userService.getUserList();//构造分页参数Page<User> page = new Page<>(pn, 2);//调用page进行分页Page<User> userPage = userService.page(page, null);long current = userPage.getCurrent();//当前是几页long pages = userPage.getPages();//当前总共的页数long total = userPage.getTotal();//总共的记录数目/条数//获取表当中的数据List<User> records = userPage.getRecords();//这个userPage里面有我们存着的当前页和我们的表中的数据（但这个数据得靠我们自己取出来）model.addAttribute("users",userPage);return "table/dynamic_table";}//删除功能//    @ResponseBody@GetMapping("/delete")public String deleteTable(@RequestParam("id") Integer id,@RequestParam(value = "pn",defaultValue = "1") Integer pn,RedirectAttributes ra) {userService.removeById(id);//这个相当于从前端获取到一个参数  然后就将其加到我们新的重定向的路径上ra.addAttribute("pn",pn);return "redirect:dynamic_table";}//修改一个用户的信息@GetMapping("/update")public String updateTable(@RequestParam("id") Integer id,@RequestParam("name") String name,@RequestParam("age") Integer age,@RequestParam("email") String email,Model model) {User user = new User();//获取到我们要修改用户的信息的id信息user.setId(id);if(name != null) user.setName(name);if(age != null) user.setAge(age);if(email != null) user.setEmail(email);userService.updateById(user);model.addAttribute("msg","修改用户信息成功");return "redirect:dynamic_table";}//增加一个用户@GetMapping("/add_table")public String addTable(@RequestParam("id") Integer id,@RequestParam("name") String name,@RequestParam("age") Integer age,@RequestParam("email") String email) {User user = new User(id, name, age, email);userService.save(user);return "redirect:dynamic_table";}@GetMapping("/editable_table")public String editable_table() {return "table/editable_table";}@GetMapping("/responsive_table")public String responsive_table() {return "table/responsive_table";}@GetMapping("/update_table.html")public String getUpdateTable (Model model,Integer id) {User user = userService.getById(id);model.addAttribute("user",user);return "table/update_table";}//转发到增加用户页面@GetMapping("add_table.html")public String addTable() {return "table/add_table";}}

7:拦截器

package com.wyj.MyLanJie;import lombok.extern.log4j.Log4j;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;@Slf4j
public class loginInterceptor implements HandlerInterceptor {/**** 方法处理前:如果返回true 那么就继续往下执行 返回false就不往下执行了** @param request* @param response* @param handler* @return* @throws Exception*//*** preHandle方法是进行处理器拦截用的，顾名思义，该方法将在Controller处理之前进行调用，SpringMVC中的Interceptor拦截器是链式的，可以同时存在* 多个Interceptor，然后SpringMVC会根据声明的前后顺序一个接一个的执行，而且所有的Interceptor中的preHandle方法都会在* Controller方法调用之前调用。SpringMVC的这种Interceptor链式结构也是可以进行中断的，这种中断方式是令preHandle的返* 回值为false，当preHandle的返回值为false的时候整个请求就结束了。*/@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {HttpSession session = request.getSession();Object loginUser = session.getAttribute("loginUser");if(loginUser != null) {return true;//放行}request.setAttribute("msg","请先登录");request.getRequestDispatcher("/login").forward(request,response);return false;}@Override//方法执行后public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {}@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {}
}

这个需要我们自动配置一下，有些页面是放行的有些页面是拦截的

package com.wyj.Config;import com.wyj.MyLanJie.loginInterceptor;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;@Configuration
public class interceptorConfig implements WebMvcConfigurer {@Overridepublic void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(new loginInterceptor())//将拦截器注册到容器中.addPathPatterns("/**")//设置拦截要求.excludePathPatterns("/","/login","/css/**","/fonts/**","/images/**","/js/**","/aa/**","/let");//放行的要求}}