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MyBatis-Plus

文档中心 2022-05-27 22:14:53 52

MyBatis-Plus

特性

  • 无侵入：只做增强不做改变，引入它不会对现有工程产生影响，如丝般顺滑
  • 损耗小：启动即会自动注入基本 CURD，性能基本无损耗，直接面向对象操作
  • 强大的 CRUD 操作：内置通用 Mapper、通用 Service，仅仅通过少量配置即可实现单表大部分 CRUD 操作，更有强大的条件构造器，满足各类使用需求
  • 支持 Lambda 形式调用：通过 Lambda 表达式，方便的编写各类查询条件，无需再担心字段写错
  • 支持主键自动生成：支持多达 4 种主键策略（内含分布式唯一 ID 生成器 - Sequence），可自由配置，完美解决主键问题
  • 支持 ActiveRecord 模式：支持 ActiveRecord 形式调用，实体类只需继承 Model 类即可进行强大的 CRUD 操作
  • 支持自定义全局通用操作：支持全局通用方法注入（ Write once, use anywhere ）
  • 内置代码生成器：采用代码或者 Maven 插件可快速生成 Mapper 、 Model 、 Service 、 Controller 层代码，支持模板引擎，更有超多自定义配置等您来使用
  • 内置分页插件：基于 MyBatis 物理分页，开发者无需关心具体操作，配置好插件之后，写分页等同于普通 List 查询
  • 分页插件支持多种数据库：支持 MySQL、MariaDB、Oracle、DB2、H2、HSQL、SQLite、Postgre、SQLServer 等多种数据库
  • 内置性能分析插件：可输出 Sql 语句以及其执行时间，建议开发测试时启用该功能，能快速揪出慢查询
  • 内置全局拦截插件：提供全表 delete 、 update 操作智能分析阻断，也可自定义拦截规则，预防误操作

CRUD扩展

添加依赖

<dependencies>    <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId>    </dependency>    <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope>    </dependency>    <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId>    </dependency>    <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-starter</artifactId> <version>3.0.5</version>    </dependency>    <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId>    </dependency></dependencies>

配置

#数据库连接配置spring.datasource.username=rootspring.datasource.password=123456spring.datasource.url=jdbc:mysql://localhost:3306/mybatis_plus?useSSL=false&useUnicode=true&characterEncoding=utf-8spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver#配置日志mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl#配置逻辑删除mybatis-plus.global-config.db-config.logic-delete-value=1mybatis-plus.global-config.db-config.logic-not-delete-value=0

在 Spring Boot 启动类中添加 @MapperScan 注解，扫描 Mapper 文件夹：

package com.yrz;import org.mybatis.spring.annotation.MapperScan;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;@MapperScan("com.yrz.mapper")@SpringBootApplicationpublic class MybatisPlusApplication {    public static void main(String[] args) { SpringApplication.run(MybatisPlusApplication.class, args);    }}

UserMapper

package com.yrz.mapper;import com.baomidou.mybatisplus.core.mapper.BaseMapper;import com.yrz.pojo.User;import org.springframework.stereotype.Repository;@Repository //代表持久层public interface UserMapper extends BaseMapper<User> {}

User

package com.yrz.pojo;import com.baomidou.mybatisplus.annotation.IdType;import com.baomidou.mybatisplus.annotation.TableId;import com.baomidou.mybatisplus.annotation.TableLogic;import com.baomidou.mybatisplus.annotation.Version;import lombok.AllArgsConstructor;import lombok.Data;import lombok.NoArgsConstructor;@Data@AllArgsConstructor@NoArgsConstructorpublic class User {    @TableId(type = IdType.INPUT)    private Long id;    private String name;    private Integer age;    private String email;    @Version //代表这是乐观锁    private Integer version;    @TableLogic //逻辑删除    private Integer deleted;}

MyBatisPlusConfig配置类

package com.yrz.config;import com.baomidou.mybatisplus.core.injector.ISqlInjector;import com.baomidou.mybatisplus.extension.injector.LogicSqlInjector;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;import org.springframework.transaction.annotation.EnableTransactionManagement;@MapperScan("com.yrz.mapper")@EnableTransactionManagement@Configurationpublic class MyBatisPlusConfig {    //配置乐观锁插件    @Bean    public OptimisticLockerInterceptor optimisticLockerInterceptor() { return new OptimisticLockerInterceptor();    }    //配置分页插件    @Bean    public PaginationInterceptor paginationInterceptor() { return new PaginationInterceptor();    }    //配置逻辑删除组件    @Bean    public ISqlInjector sqlInjector(){ return new LogicSqlInjector();    }}

测试类

package com.yrz;import com.baomidou.mybatisplus.extension.plugins.pagination.Page;import com.yrz.mapper.UserMapper;import com.yrz.pojo.User;import org.junit.jupiter.api.Test;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.context.SpringBootTest;import java.sql.SQLOutput;import java.util.ArrayList;import java.util.Arrays;import java.util.HashMap;import java.util.List;@SpringBootTestclass MybatisPlusApplicationTests {    @Autowired    private UserMapper userMapper;    @Test    void contextLoads() { List<User> users = userMapper.selectList(null); users.forEach(System.out::println);    } //插入测试    @Test    public void testInsert(){ User user = new User(); user.setName("xxx"); user.setAge(3); user.setEmail("123@qq.com"); user.setId(8L); int result = userMapper.insert(user); System.out.println(user); System.out.println(result);    }    //更新测试    @Test    public void testUpdate(){ User user = new User(); user.setId(6L); user.setName("yrz"); user.setAge(18); user.setEmail("123@qq.com"); int i = userMapper.updateById(user); System.out.println(i);    }    //测试乐观锁成功    @Test    public void testOptimisticLocker(){ User user = userMapper.selectById(1); user.setName("lwh"); user.setEmail("456@qq.com"); userMapper.updateById(user);    }    //测试乐观锁失败    @Test    public void testOptimisticLocker2(){ //线程1 User user = userMapper.selectById(1); user.setName("lwh1"); user.setEmail("456@qq.com"); //线程2 User user2 = userMapper.selectById(1); user2.setName("lwh2"); user2.setEmail("456@qq.com"); userMapper.updateById(user2); userMapper.updateById(user);    }    //查询测试    @Test    public void testSelectById(){ User user = userMapper.selectById(6); System.out.println(user);    }    //批量查询    @Test    public void testSelectBatchId(){ List<User> users = userMapper.selectBatchIds(Arrays.asList(1, 2, 3)); users.forEach(System.out::println);    }    //条件查询 map    @Test    public void testSelectBatchIds(){ HashMap<String, Object> map = new HashMap<>(); map.put("name","yrz"); map.put("age", 18); List<User> users = userMapper.selectByMap(map); users.forEach(System.out::println);    }    //分页查询测试    @Test    public void testPage(){ Page<User> page = new Page<>(1, 5); userMapper.selectPage(page, null); page.getRecords().forEach(System.out::println); System.out.println(page.getTotal());    }    //删除测试    @Test    public void testDeleteById(){ userMapper.deleteById(8L);    }}

性能分析插件

#设置开发环境spring.profiles.active=dev

导入插件

    //SQL执行效率插件 性能分析插件    @Bean    @Profile({"dev","test"})// 设置 dev test 环境开启    public PerformanceInterceptor performanceInterceptor() { PerformanceInterceptor performanceInterceptor =  new PerformanceInterceptor(); performanceInterceptor.setFormat(true);//格式化语句 performanceInterceptor.setMaxTime(5);//执行时间超过多少秒会抛出异常 return  performanceInterceptor;    }

测试查询

@Testvoid contextLoads() {    List<User> users = userMapper.selectList(null);    users.forEach(System.out::println);}

条件构造器

Wrapper（十分重要）

package com.yrz;import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;import com.yrz.mapper.UserMapper;import com.yrz.pojo.User;import org.junit.jupiter.api.Test;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.boot.test.context.SpringBootTest;@SpringBootTestpublic class WrapperTest {    @Autowired    private UserMapper userMapper;    @Test    void test1() { QueryWrapper<User> wrapper = new QueryWrapper<>(); wrapper  .isNotNull("name")  .isNotNull("email")  .ge("age", 12);  //ge大于等于;le小于等于   gt大于;lt小于 userMapper.selectList(wrapper).forEach(System.out::println);    }    @Test    void test2() { QueryWrapper<User> wrapper = new QueryWrapper<>(); wrapper.eq("name", "yrz"); userMapper.selectList(wrapper).forEach(System.out::println);    }    @Test    void test3() { QueryWrapper<User> wrapper = new QueryWrapper<>(); wrapper.between("age", 20,30); // 区间查询 System.out.println(userMapper.selectCount(wrapper));    }    //模糊查询    @Test    void test4() { QueryWrapper<User> wrapper = new QueryWrapper<>(); wrapper  .notLike("name", "y")  .likeRight("email", "t"); userMapper.selectMaps(wrapper).forEach(System.out::println);    }    @Test    void test5() { QueryWrapper<User> wrapper = new QueryWrapper<>(); wrapper.inSql("id", "select id from user where id<3"); userMapper.selectObjs(wrapper).forEach(System.out::println);    }    @Test    void test6() { QueryWrapper<User> wrapper = new QueryWrapper<>(); wrapper.orderByDesc("id"); //wrapper.orderByAsc("id");  升序排序 userMapper.selectList(wrapper).forEach(System.out::println);    }}

代码自动生成器

package com.yrz;import com.baomidou.mybatisplus.annotation.DbType;import com.baomidou.mybatisplus.annotation.IdType;import com.baomidou.mybatisplus.generator.config.DataSourceConfig;import com.baomidou.mybatisplus.generator.config.GlobalConfig;import com.baomidou.mybatisplus.generator.AutoGenerator;import com.baomidou.mybatisplus.generator.config.PackageConfig;import com.baomidou.mybatisplus.generator.config.StrategyConfig;import com.baomidou.mybatisplus.generator.config.rules.DateType;import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy;//代码自动生成器public class CodeGenerator  {    public static void main(String[] args) { //需要构建一个代码自动生成器对象 AutoGenerator mpg = new AutoGenerator(); //策略配置 //1、全局配置 GlobalConfig gc = new GlobalConfig(); String projectPath = System.getProperty("user.dir"); gc.setOutputDir(projectPath + "/src/main/java"); gc.setAuthor("YRZ"); gc.setOpen(false); gc.setFileOverride(false); //是否覆盖 gc.setServiceName("%sService"); //去Service的I前缀 gc.setIdType(IdType.ID_WORKER); gc.setDateType(DateType.ONLY_DATE); gc.setSwagger2(true); mpg.setGlobalConfig(gc); //2、设置数据源 DataSourceConfig dsc = new DataSourceConfig(); dsc.setUrl("jdbc:mysql://localhost:3306/mybatis_plus?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8"); dsc.setDriverName("com.mysql.cj.jdbc.Driver"); dsc.setUsername("root"); dsc.setPassword("123456"); dsc.setDbType(DbType.MYSQL); mpg.setDataSource(dsc); //3、包的配置 PackageConfig pc = new PackageConfig(); pc.setModuleName("blog"); pc.setParent("com"); pc.setEntity("entity"); pc.setMapper("mapper"); pc.setService("service"); pc.setController("controller"); mpg.setPackageInfo(pc); //4、策略配置 StrategyConfig strategy = new StrategyConfig(); strategy.setInclude("user"); //设置要映射的表名 strategy.setNaming(NamingStrategy.underline_to_camel); strategy.setColumnNaming(NamingStrategy.underline_to_camel); strategy.setEntityLombokModel(true); //自动lombok strategy.setRestControllerStyle(true); strategy.setLogicDeleteFieldName("delete"); strategy.setVersionFieldName("version"); //乐观锁 strategy.setControllerMappingHyphenStyle(true); mpg.setStrategy(strategy); mpg.execute(); //执行    }}
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