Mybatis-plus框架使用配置

mybatis-plus框架使用配置

MyBatis-Plus（简称 MP）是一个基于 MyBatis 的增强工具，它对 Mybatis 的基础功能进行了增强，但未做任何改变。使得我们可以可以在 Mybatis 开发的项目上直接进行升级为 Mybatis-plus，正如它对自己的定位，它能够帮助我们进一步简化开发过程，提高开发效率。

Mybatis-Plus 其实可以看作是对 Mybatis 的再一次封装，升级之后，对于单表的 CRUD 操作，调用 Mybatis-Plus 所提供的 api 就能够轻松实现，此外还提供了各种查询方式、分页等行为。最最重要的，开发人员还不用去编写 XML，这就大大降低了开发难度
一、引入依赖

<dependency>                <groupId>org.springframework.bootgroupId>                <artifactId>spring-boot-starter-WEBartifactId>                <version>2.3.3.RELEASEversion>            dependency><dependency>                <groupId>com.baomidougroupId>                <artifactId>mybatis-plus-annotationartifactId>                <version>3.3.2version>            dependency><dependency>                <groupId>com.baomidougroupId>                <artifactId>mybatis-plus-boot-starterartifactId>                <version>3.3.2version>            dependency>                        <dependency>                <groupId>com.GitHub.pagehelpergroupId>                <artifactId>pagehelper-spring-boot-starterartifactId>                <version>1.2.12version>            dependency>                        <dependency>                <groupId>MysqlgroupId>                <artifactId>mysql-connector-javaartifactId>                <version>5.1.9version>            dependency>                        <dependency>                <groupId>com.alibabagroupId>                <artifactId>druid-spring-boot-starterartifactId>                <version>1.1.10version>            dependency>                       <dependency>                <groupId>cn.hutoolgroupId>                <artifactId>hutool-allartifactId>                <version>5.8.5version>            dependency><dependency>                <groupId>com.alibabagroupId>                <artifactId>fastJSONartifactId>                <version>1.2.21version>            dependency>                        <dependency>                <groupId>org.projectlombokgroupId>                <artifactId>lombokartifactId>                <version>1.18.16version>            dependency>

二、application.yml文件配置

#服务端口号server:  port: 9022#mybatis配置mybatis-plus:  mapper-locations: classpath:/mapper/*.xml  configuration:    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl    call-setters-on-nulls: true#数据库配置spring:  datasource:    driver-class-name: com.mysql.jdbc.Driver    type: com.alibaba.druid.pool.DruidDataSource    url: jdbc:mysql://localhost:3306/supply_Goods?useUnicode=true&characterEncoding=utf8    username: root    passWord: 123456

三、数据库表sql

CREATE TABLE `user` (  `id` bigint(18) NOT NULL AUTO_INCREMENT COMMENT 'id',  `username` varchar(255) DEFAULT NULL COMMENT '用户名',  `password` varchar(255) DEFAULT NULL COMMENT '密码',  `sex` tinyint(1) DEFAULT NULL COMMENT '性别：0男、1女',  `dept` varchar(255) DEFAULT NULL COMMENT '部门',  `created` datetime DEFAULT NULL COMMENT '创建时间',  `create_by` bigint(20) DEFAULT NULL COMMENT '创建人',  `modify_by` bigint(20) DEFAULT NULL COMMENT '更新人',  `last_update_time` datetime DEFAULT NULL COMMENT '更新时间',  `del_flag` tinyint(1) DEFAULT '0' COMMENT '是否删除：0未删除 1已删除',  PRIMARY KEY (`id`)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

四、实体类
sql在线生成s实体类：https://java.bejson.com/generator/

package com.supplier.domain;import com.baomidou.mybatisplus.annotation.*;import lombok.Data;import java.io.Serializable;import java.util.Date;@TableName("user")@Datapublic class User implements Serializable {        @TableId(type = IdType.AUTO)    private Integer id;        private String username;        private String password;        private Integer sex;        private String dept;        @TableField(value = "create_by", fill = FieldFill.INSERT)    private String createBy;        @TableField(value = "modify_by", fill = FieldFill.UPDATE)    private String modifyBy;        @TableField(value = "created", fill = FieldFill.INSERT)    private Date created;        @TableField(value = "last_update_time", fill = FieldFill.INSERT_UPDATE)    private Date lastUpdateTime;        private Boolean delFlag;        @TableField(exist = false)    private String exit;}

返回实体类

package com.supplier.model;import com.supplier.constant.SysConstant;import lombok.Data;import java.io.Serializable;@Datapublic class R<T> implements Serializable {    private static final long serialVersionUID = 1L;        private int code;        private String msg;        private T data;    public static <T> R<T> ok() {        return restResult(null, SysConstant.SUCCESS_CODE, SysConstant.SUCCESS_MSG);    }    public static <T> R<T> ok(T data) {        return restResult(data, SysConstant.SUCCESS_CODE, SysConstant.SUCCESS_MSG);    }    public static <T> R<T> ok(T data, String msg) {        return restResult(data, SysConstant.SUCCESS_CODE, msg);    }    public static <T> R<T> fail() {        return restResult(null, SysConstant.FAIL_CODE, SysConstant.FAIL_MSG);    }    public static <T> R<T> fail(String msg) {        return restResult(null, SysConstant.FAIL_CODE, msg);    }    public static <T> R<T> fail(T data) {        return restResult(data, SysConstant.FAIL_CODE, SysConstant.FAIL_MSG);    }    public static <T> R<T> fail(T data, String msg) {        return restResult(data, SysConstant.FAIL_CODE, msg);    }    public static <T> R<T> fail(int code, String msg) {        return restResult(null, code, msg);    }    private static <T> R<T> restResult(T data, int code, String msg) {        R<T> apiResult = new R<>();        apiResult.setCode(code);        apiResult.setData(data);        apiResult.setMsg(msg);        return apiResult;    }}

package com.supplier.constant;public interface SysConstant {        String SUCCESS_MSG = "请求成功!";    int SUCCESS_CODE = 200;        String FAIL_MSG = "请求失败!";    int FAIL_CODE = 500;}

分页实体类

package com.supplier.model;import lombok.Data;import lombok.NoArgsConstructor;import java.io.Serializable;import java.util.List;@Data@NoArgsConstructorpublic class PageModel<T> implements Serializable {        public int pageNum;        public int pageSize;        public long total;        public List list;        public PageModel(int pageNum, int pageSize, long total, List list) {        this.pageNum = pageNum;        this.pageSize = pageSize;        this.total = total;        this.list = list;    }}

五、配置类
mybatis-plus分页配置(也可以直接引入mybatis分页插件)

package com.supplier.config;import com.baomidou.mybatisplus.annotation.DbType;import com.baomidou.mybatisplus.core.incrementer.IKeyGenerator;import com.baomidou.mybatisplus.extension.incrementer.H2KeyGenerator;import com.baomidou.mybatisplus.extension.plugins.OptimisticLockerInterceptor;import com.baomidou.mybatisplus.extension.plugins.PaginationInterceptor;import org.mybatis.spring.annotation.MapperScan;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.Configuration;@Configuration@MapperScan("com.supplier.mapper")public class MybatisPlusConfig {        @Bean    public PaginationInterceptor paginationInterceptor() {        PaginationInterceptor paginationInterceptor = new PaginationInterceptor();        paginationInterceptor.setDbType(DbType.MYSQL);        return paginationInterceptor;    }        @Bean    public OptimisticLockerInterceptor optimisticLockerInterceptor() {        return new OptimisticLockerInterceptor();    }    @Bean    public IKeyGenerator iKeyGenerator() {        return new H2KeyGenerator();    }}

插入、更新时设置字段默认值，更新时必须使用一下方式才生效

package com.supplier.config;import com.baomidou.mybatisplus.core.handlers.MetaObjectHandler;import lombok.extern.slf4j.Slf4j;import org.apache.ibatis.reflection.MetaObject;import org.springframework.stereotype.Component;import java.util.Date;@Slf4j@Componentpublic class AutoFillHandler implements MetaObjectHandler {        @Override    public void insertFill(MetaObject metaObject) {        String userId = "1234";        this.strictInsertFill(metaObject, "createBy", String.class, userId);        this.strictInsertFill(metaObject, "created", Date.class, new Date());        this.strictInsertFill(metaObject, "lastUpdateTime", Date.class, new Date());    }        @Override    public void updateFill(MetaObject metaObject) {        String userId = "22";        this.strictUpdateFill(metaObject, "modifyBy", String.class, userId);        this.strictUpdateFill(metaObject, "lastUpdateTime", Date.class, new Date());    }}

六、业务逻辑处理（Service接口类）

package com.supplier.service;import com.baomidou.mybatisplus.extension.service.IService;import com.supplier.domain.User;import com.supplier.model.PageModel;public interface UserService extends IService<User> {        void add(User user);        void modify(User user);            User detail(Integer id);        PageModel lists(Integer pageNum,Integer pageSize);        void delete(Integer id);}

实现类

package com.supplier.service.impl;import cn.hutool.core.bean.BeanUtil;import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;import com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper;import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;import com.github.pagehelper.Page;import com.github.pagehelper.PageHelper;import com.supplier.domain.User;import com.supplier.mapper.UserMapper;import com.supplier.model.PageModel;import com.supplier.service.UserService;import org.apache.commons.lang3.StringUtils;import org.springframework.stereotype.Service;import java.util.List;@Servicepublic class UserServiceImpl extends ServiceImpl<UserMapper, User> implements UserService {    @Override    public void add(User user) {        this.baseMapper.insert(user);    }    @Override    public void modify(User user) {        //当重新new对象时，会调用自动填充更新时间和更新人的数据        User userNews = new User();        BeanUtil.copyProperties(user,userNews);        UpdateWrapper<User> userUpdateWrapper = new UpdateWrapper<>();        userUpdateWrapper.eq("id",user.getId());        this.baseMapper.update(user,userUpdateWrapper);    }    @Override    public User detail(Integer id) {        //需要筛选条件时        return this.baseMapper.selectOne(new QueryWrapper<User>().eq("id",id).last("limit 1"));    }    public PageModel listsTwo(Integer pageNum,Integer pageSize) {        //第一种分页，使用mybatis插件        PageHelper.startPage(pageNum,pageSize);        Page<User> list = this.baseMapper.lists();        return new PageModel(pageNum,pageSize,list.getTotal(),list.getResult());    }    @Override    public PageModel lists(Integer pageNum,Integer pageSize){        //第二种分页,mybatis-plus分页        com.baomidou.mybatisplus.extension.plugins.pagination.Page<User> userPage = new com.baomidou.mybatisplus.extension.plugins.pagination.Page<>(pageNum,pageSize);        com.baomidou.mybatisplus.extension.plugins.pagination.Page<User> list = this.baseMapper.selectPage(userPage, null);        return new PageModel(pageNum,pageSize,list.getTotal(),list.getRecords());    }    public List<User> selectInfo(String username, Integer sex) {        QueryWrapper<User> queryWrapper = new QueryWrapper();        //使用eq表示查询值为必填,select表示查询字段        queryWrapper.like(StringUtils.isNoneBlank(username),"username",username).eq("sex",sex).select("id","username");        //无查询条件        return this.baseMapper.selectList(queryWrapper);    }    @Override    public void delete(Integer id) {        this.baseMapper.deleteById(id);    }}

七、数据访问层（dao接口类）

package com.supplier.mapper;import com.baomidou.mybatisplus.core.mapper.BaseMapper;import com.github.pagehelper.Page;import com.supplier.domain.User;import org.apache.ibatis.annotations.Mapper;@Mapperpublic interface UserMapper extends BaseMapper<User> {    Page<User> lists();}

mapper文件

DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "Http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.supplier.mapper.UserMapper">    <select id="lists" resultType="com.supplier.domain.User">        select * from `user`    select>mapper>

八、控制层（controller）

package com.supplier.controller;import com.supplier.domain.User;import com.supplier.model.R;import com.supplier.service.UserService;import org.springframework.web.bind.annotation.*;@RestController@RequestMapping("/user")public class UserController {    private final UserService userService;    public UserController(UserService userService) {        this.userService = userService;    }        @PostMapping    public R add(@RequestBody User user){        userService.add(user);        return R.ok();    }        @PutMapping    public R modify(@RequestBody User user){        userService.modify(user);        return R.ok();    }        @GetMapping("/{id}")    public R detail(@PathVariable Integer id){        return R.ok(userService.detail(id));    }        @GetMapping    public R list(@RequestParam(defaultValue = "1") Integer pageNum,@RequestParam(defaultValue = "10")Integer pageSize){        return R.ok(userService.lists(pageNum,pageSize));    }        @DeleteMapping    public R delete(Integer id){        userService.delete(id);        return R.ok();    }}

来源地址：https://blog.csdn.net/m0_46300599/article/details/127999193