集成mybatisplus后，简单的CRUD就不用写了，如果没有特别的sql，就可以不用mapper的xml文件的。

目录

pom.xml文件

<?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>1.5.21.RELEASE</version>  <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.xiaostudy</groupId> <artifactId>demo1</artifactId> <version>0.0.1-SNAPSHOT</version> <name>demo1</name> <description>Demo project for Spring Boot</description> <properties>  <java.version>1.8</java.version> </properties> <dependencies>  <!-- spring-boot -->  <dependency>   <groupId>org.springframework.boot</groupId>   <artifactId>spring-boot-starter-web</artifactId>  </dependency>  <dependency>   <groupId>org.springframework.boot</groupId>   <artifactId>spring-boot-starter</artifactId>  </dependency>  <dependency>   <groupId>org.springframework.boot</groupId>   <artifactId>spring-boot-starter-test</artifactId>   <scope>test</scope>  </dependency>  <!--mybatis-plus自动的维护了mybatis以及mybatis-spring的依赖，  在springboot中这三者不能同时的出现，避免版本的冲突，表示：跳进过这个坑-->  <dependency>   <groupId>com.baomidou</groupId>   <artifactId>mybatis-plus-boot-starter</artifactId>   <version>3.1.1</version>  </dependency>  <!-- 引入Druid依赖，阿里巴巴所提供的数据源 -->  <dependency>   <groupId>com.alibaba</groupId>   <artifactId>druid</artifactId>   <version>1.0.29</version>  </dependency>  <!-- 提供mysql驱动 -->  <dependency>   <groupId>mysql</groupId>   <artifactId>mysql-connector-java</artifactId>   <version>5.1.38</version>  </dependency> </dependencies> <build>  <plugins>   <plugin>    <groupId>org.springframework.boot</groupId>    <artifactId>spring-boot-maven-plugin</artifactId>   </plugin>  </plugins> </build></project>

实体类User

package com.xiaostudy.demo1.entity;import com.baomidou.mybatisplus.annotation.TableName;import java.io.Serializable;@TableName("t_user")public class User implements Serializable { private String id; private String userName; private String userPassword; public String getId() {  return id; } public void setId(String id) {  this.id = id; } public String getUserName() {  return userName; } public void setUserName(String userName) {  this.userName = userName; } public String getUserPassword() {  return userPassword; } public void setUserPassword(String userPassword) {  this.userPassword = userPassword; } @Override public String toString() {  return "User{" +    "id='" + id + '\'' +    ", userName='" + userName + '\'' +    ", userPassword='" + userPassword + '\'' +    '}'; }}