Mybatis-Plus 分页、逻辑删除、乐观锁快速入门

前置配置

表结构

数据库使用Oracle数据库

-- ---------------------------- -- Table structure for T_USER -- ---------------------------- DROP TABLE "SCOTT"."T_USER"; CREATE TABLE "SCOTT"."T_USER" ( "ID" VARCHAR2(19 BYTE) NOT NULL, "NAME" VARCHAR2(50 BYTE) NOT NULL, "AGE" NUMBER(3,0) NOT NULL, "DELETED" NUMBER(1,0) DEFAULT 0, "VERSION" NUMBER(10,0) DEFAULT 1 ) LOGGING NOCOMPRESS PCTFREE 10 INITRANS 1 STORAGE ( INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645 BUFFER_POOL DEFAULT ) PARALLEL 1 NOCACHE DISABLE ROW MOVEMENT ; COMMENT ON COLUMN "SCOTT"."T_USER"."ID" IS '主键'; COMMENT ON COLUMN "SCOTT"."T_USER"."NAME" IS '姓名'; COMMENT ON COLUMN "SCOTT"."T_USER"."AGE" IS '年龄'; COMMENT ON COLUMN "SCOTT"."T_USER"."DELETED" IS '逻辑删除 （0未删除,1已删除）'; COMMENT ON COLUMN "SCOTT"."T_USER"."VERSION" IS '版本控制（乐观锁）'; COMMENT ON TABLE "SCOTT"."T_USER" IS '用户表'; -- ---------------------------- -- Records of T_USER -- ---------------------------- INSERT INTO "SCOTT"."T_USER" VALUES ('1', 'xy', '19', '0', '1'); INSERT INTO "SCOTT"."T_USER" VALUES ('2', 'jack', '20', '0', '1'); INSERT INTO "SCOTT"."T_USER" VALUES ('3', 'lily', '21', '0', '1'); INSERT INTO "SCOTT"."T_USER" VALUES ('4', 'scott', '19', '0', '1'); INSERT INTO "SCOTT"."T_USER" VALUES ('5', 'smith', '20', '0', '1'); -- ---------------------------- -- Primary Key structure for table T_USER -- ---------------------------- ALTER TABLE "SCOTT"."T_USER" ADD CONSTRAINT "PK_T_USER_ID" PRIMARY KEY ("ID"); -- ---------------------------- -- Checks structure for table T_USER -- ---------------------------- ALTER TABLE "SCOTT"."T_USER" ADD CONSTRAINT "SYS_C0011157" CHECK ("ID" IS NOT NULL) NOT DEFERRABLE INITIALLY IMMEDIATE NORELY VALIDATE; ALTER TABLE "SCOTT"."T_USER" ADD CONSTRAINT "SYS_C0011158" CHECK ("NAME" IS NOT NULL) NOT DEFERRABLE INITIALLY IMMEDIATE NORELY VALIDATE; ALTER TABLE "SCOTT"."T_USER" ADD CONSTRAINT "SYS_C0011159" CHECK ("AGE" IS NOT NULL) NOT DEFERRABLE INITIALLY IMMEDIATE NORELY VALIDATE;

domain类

@TableName(value ="T_USER") @Data public class User implements Serializable { /** * 主键 */ @TableId private String id; /** * 姓名 */ private String name; /** * 年龄 */ private Integer age; /** * 逻辑删除 （0未删除,1已删除） */ @TableField(select = false) // 查询时不会出现在select语句中 private Integer deleted; /** * 版本控制（乐观锁） */ @TableField(select = false) // 查询时不会出现在select语句中 private Integer version; @TableField(exist = false) private static final long serialVersionUID = 1L; @Override public String toString() { return "User{" + "id='" + id + '\'' + ", name='" + name + '\'' + ", age=" + age + '}'; } }

mapper类

@Mapper public interface UserMapper extends BaseMapper<User> { }

开启分页

添加分页拦截器

@Configuration public class MyBatisPlusConfig { @Bean public MybatisPlusInterceptor mybatisPlusInterceptor() { MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor(); // 添加分页拦截器 mybatisPlusInterceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor()); return mybatisPlusInterceptor; } }

测试代码

@Test void testSelectPage() { Page<User> page = new Page<>(1, 2); userMapper.selectPage(page, null); System.out.println("page.getCurrent() = " + page.getCurrent()); System.out.println("page.getSize() = " + page.getSize()); System.out.println("page.getPages() = " + page.getPages()); System.out.println("page.getTotal() = " + page.getTotal()); System.out.println("page.getRecords() = " + page.getRecords()); }

查询结果:

开启逻辑删除

配置逻辑删除

• 方式一 在user.java 中的delete字段下添加如下注解

/** * 逻辑删除 （0未删除,1已删除） */ @TableField(select = false) // 查询时不会出现在select语句中 @TableLogic(delval = "1",value = "0") private Integer deleted;

• 方式二 在 application.yml 配置文件中添加以下配置：

mybatis-plus: global-config: db-config: logic-delete-field: deleted logic-delete-value: 1 logic-not-delete-value: 0

测试代码

@Test void testLogicDelete() { userMapper.selectList(null).forEach(System.out::println); userMapper.deleteById(1); userMapper.selectList(null).forEach(System.out::println); }

查询结果:

查询所有数据方法

该方法不一定满足复杂业务逻辑，如需复杂操作，请自定义sql查询

@Test void testSelectLogicDeleteAndNotDeleted() { LambdaQueryWrapper<User> queryWrapper = new LambdaQueryWrapper<>(); queryWrapper.last("or deleted = 1"); userMapper.selectList(queryWrapper); }

查询结果：

开启乐观锁

添加乐观锁拦截器

@Configuration public class MyBatisPlusConfig { @Bean public MybatisPlusInterceptor mybatisPlusInterceptor() { MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor(); // 添加分页拦截器 mybatisPlusInterceptor.addInnerInterceptor(new PaginationInnerInterceptor()); // 添加乐观锁拦截器 mybatisPlusInterceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor()); return mybatisPlusInterceptor; } }

开启乐观锁注解

在user.java 中的delete字段下添加如下注解

/** * 版本控制（乐观锁） */ @Version private Integer version;

测试代码

@Test void testVersion() { User user1 = userMapper.selectById(2); User user2 = userMapper.selectById(2); user1.setName("xy"); System.out.println("userMapper.updateById(user) = " + userMapper.updateById(user1)); user2.setName("xy"); System.out.println("userMapper.updateById(user) = " + userMapper.updateById(user2)); }

查询结果