12.代码自动生成器 代码自动生成器package com.sw.mybatisplus; import com.baomidou.mybatisplus.annotation.DbType; import com.baomidou.mybatisplus.annotation.FieldFill; import com.baomidou.mybatisplus.annotation.IdType; import com.baomidou.mybatisplus.generator.AutoGenerator; import com.baomidou.mybatisplus.generator.config.DataSourceConfig; import com.baomidou.mybatisplus.generator.config.GlobalConfig; import com.baomidou.mybatisplus.generator.config.PackageConfig; import com.baomidou.mybatisplus.generator.config.StrategyConfig; import com.baomidou.mybatisplus.generator.config.po.TableFill; import com.baomidou.mybatisplus.generator.config.rules.DateType; import com.baomidou.mybatisplus.generator.config.rules.NamingStrategy; import java.util.ArrayList; /** * @Author suaxi * @Date 2021/4/5 22:10 */ public class CodeGenerator { public static void main(String[] args) { AutoGenerator generator = new AutoGenerator(); //全局配置 GlobalConfig gc = new GlobalConfig(); String projectPath = System.getProperty("user.dir"); gc.setOutputDir(projectPath + "/src/main/java"); gc.setAuthor("suaxi"); //是否打开输出目录 gc.setOpen(false); //是否覆盖之前的 gc.setFileOverride(false); //正则匹配去掉Serivce前的 I gc.setServiceName("%sService"); gc.setIdType(IdType.ID_WORKER); gc.setDateType(DateType.ONLY_DATE); gc.setSwagger2(true); generator.setGlobalConfig(gc); //设置数据源 DataSourceConfig dsc = new DataSourceConfig(); dsc.setUrl("jdbc:mysql://localhost:3306/mybatis_plus?useSSL=true&serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf-8"); dsc.setDriverName("com.mysql.cj.jdbc.Driver"); dsc.setUsername("root"); dsc.setPassword("123456"); dsc.setDbType(DbType.MYSQL); generator.setDataSource(dsc); //包配置 PackageConfig pc = new PackageConfig(); pc.setModuleName("demo"); pc.setParent("com.sw"); pc.setEntity("pojo"); pc.setMapper("mapper"); pc.setService("service"); pc.setController("controller"); generator.setPackageInfo(pc); //策略配置 StrategyConfig sc = new StrategyConfig(); //映射的表名 sc.setInclude(""); sc.setNaming(NamingStrategy.underline_to_camel); sc.setColumnNaming(NamingStrategy.underline_to_camel); sc.setEntityLombokModel(true); //逻辑删除 sc.setLogicDeleteFieldName("delete"); //自动填充 TableFill createTime = new TableFill("create_Time", FieldFill.INSERT); TableFill updateTime = new TableFill("update_Time", FieldFill.INSERT_UPDATE); ArrayList<TableFill> list = new ArrayList<>(); list.add(createTime); list.add(updateTime); sc.setTableFillList(list); //乐观锁 sc.setVersionFieldName("version"); //请求链接驼峰转下划线：localhost:8088/test/user_id_age sc.setControllerMappingHyphenStyle(true); generator.setStrategy(sc); //执行自动生成 generator.execute(); } }

11.条件构造器 QueryWrapper 条件构造器条件查询：@Test void findTest(){ //查询姓名、邮箱不为空，且年龄大于25的用户信息 QueryWrapper<User> wrapper = new QueryWrapper<>(); wrapper.isNotNull("name") .isNotNull("email") .ge("age",25); mapper.selectList(wrapper).forEach(System.out::println); } @Test void findTest01(){ //查询一个名字为刘波的用户 QueryWrapper<User> wrapper = new QueryWrapper<>(); wrapper.ge("name","刘波"); User user = mapper.selectOne(wrapper); System.out.println(user); } @Test void findTest02(){ //查询年龄在20-30岁之间的用户 QueryWrapper<User> wrapper = new QueryWrapper<>(); wrapper.between("age", 20, 30); Integer result = mapper.selectCount(wrapper); System.out.println(result); }模糊查询：@Test void findTest03(){ //查询名字中不包含“刘”，且邮箱以"t"开头的用户 //likeRight str% //likeLeft %str QueryWrapper<User> wrapper = new QueryWrapper<>(); wrapper.notLike("name", "刘") .likeRight("email", "t"); List<Map<String, Object>> maps = mapper.selectMaps(wrapper); maps.forEach(System.out::println); }子查询:@Test void findTest04(){ //查询id大于5的用户 /* WHERE deleted=0 AND id IN ( select id from user where id > 5 ) */ QueryWrapper<User> wrapper = new QueryWrapper<>(); wrapper.inSql("id", "select id from user where id > 5"); List<Object> maps = mapper.selectObjs(wrapper); maps.forEach(System.out::println); }排序：@Test void findTest05(){ //通过id降序排列 QueryWrapper<User> wrapper = new QueryWrapper<>(); wrapper.orderByDesc("id"); List<User> users = mapper.selectList(wrapper); users.forEach(System.out::println); }

10.性能分析 性能分析注册Bean：//性能分析 @Bean @Profile({"dev", "test"}) public PerformanceInterceptor performanceInterceptor(){ PerformanceInterceptor interceptor = new PerformanceInterceptor(); //sql最大执行时间，超过则不执行，单位：ms interceptor.setMaxTime(100); //是否格式化 interceptor.setFormat(true); return interceptor; }

8.删除 删除根据id删除单条记录根据ids批量删除条件删除根据map删除

9.逻辑删除 逻辑删除物理删除：从数据库中直接移除逻辑删除：数据库中没有移除，而是通过一个变量来使该条数据失效1.数据库增加delete字段，默认值为02.实体类增加属性@TableLogic private int deleted;3.注册Bean//逻辑删除 @Bean public ISqlInjector sqlInjector(){ return new LogicSqlInjector(); }4.application.yml配置mybatis-plus: global-config: db-config: logic-delete-value: 1 logic-not-delete-value: 05.单元测试//逻辑删除测试 @Test void logicDeleteTest(){ userMapper.deleteById(1L); //sql：UPDATE user SET deleted=1 WHERE id=? AND deleted=0 User user = userMapper.selectById(1L); System.out.println(user); //输出结果为null //查询时会自动过滤delete=1的值 }

7.分页查询 分页查询1.在Config中配置分页插件//分页插件 @Bean public PaginationInterceptor paginationInterceptor(){ return new PaginationInterceptor(); }2.分页测试//分页测试 @Test void pageTest(){ //pageNum, pageSize Page<User> page = new Page<>(1,5); userMapper.selectPage(page,null); page.getRecords().forEach(System.out::println); //SELECT id,name,age,email,version,create_time,update_time FROM user LIMIT 0,5 }

6.查询 查询//查询 @Test void findByIdTest(){ User user = userMapper.selectById(1); System.out.println(user); } //批量查询 @Test void findTest(){ List<User> users = userMapper.selectBatchIds(Arrays.asList(1, 2, 3, 4)); users.forEach(System.out::println); //SELECT id,name,age,email,version,create_time,update_time FROM user WHERE id IN ( ? , ? , ? , ? ) } //条件查询（map） @Test void findTestByMap(){ Map<String, Object> map = new HashMap<>(); map.put("name","刘波"); List<User> users = userMapper.selectByMap(map); users.forEach(System.out::println); }

5.乐观锁 乐观锁乐观锁实现方式：取出记录时，获取当前version更新时，带上这个version执行更新时， set version = newVersion where version = oldVersion如果version不对，就更新失败--A线程 update user set name = 'test',version = version + 1 where id = 1 and version = 1; --B线程（此时如果B线程抢先完成修改操作，则A线程会执行失败） update user set name = 'test',version = version + 1 where id = 1 and version = 1;乐观锁插件测试1.数据库增加version字段，并设置默认值为12.实体类@Version private int version;3.注册组件package com.sw.mybatisplus.config; import com.baomidou.mybatisplus.extension.plugins.OptimisticLockerInterceptor; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.transaction.annotation.EnableTransactionManagement; /** * @Author suaxi * @Date 2021/4/5 11:48 */ @EnableTransactionManagement @Configuration public class MyBatisPlusConfig { //注册乐观锁插件 @Bean public OptimisticLockerInterceptor optimisticLockerInterceptor(){ return new OptimisticLockerInterceptor(); } } 4.单元测试 @Test void update(){ User user = new User(); user.setId(11); user.setName("自动填充测试"); user.setAge(30); int result = userMapper.updateById(user); System.out.println(result); } //测试乐观锁（成功） @Test void OptimisticLockerInterceptorTest1(){ //1.查询用户信息 User user = userMapper.selectById(10L); //2.修改信息 user.setName("乐观锁测试01"); //3.执行更新 userMapper.updateById(user); } //测试乐观锁（失败）（模拟多线程） @Test void OptimisticLockerInterceptorTest2(){ User user = userMapper.selectById(10L); user.setName("乐观锁测试111"); //模拟插队 User user1 = userMapper.selectById(10L); user1.setName("乐观锁测试222"); userMapper.updateById(user1); //自旋锁尝试多次提交 userMapper.updateById(user); }