一、逻辑删除
曾经我们写的删除代码都是物理删除。
逻辑删除：删除转变为更新
update user set deleted=1 where id = 1 and deleted=0
查找: 追加 where 条件过滤掉已删除数据,如果使用 wrapper.entity 生成的 where 条件也会自动追加该字段
查找:
select id,name,deleted from user where deleted=0
1.修改表结构
-
给 user 表增加 deleted 字段（1代表删除0代表未删除）
CREATE TABLE `user` ( `id` bigint NOT NULL AUTO_INCREMENT COMMENT '主键ID', `name` varchar(30) DEFAULT NULL COMMENT '姓名', `age` int DEFAULT NULL COMMENT '年龄', `uemail` varchar(128) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci DEFAULT NULL COMMENT '邮箱', `deleted` int DEFAULT '0' COMMENT '删除与否', PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=8 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci; -
修改字段的方式
ALTER TABLE user ADD column `deleted` int DEFAULT '0' COMMENT '删除与否';
2.开启配置支持
-
配置
com.baomidou.mybatisplus.core.config.GlobalConfig$DbConfigmybatis-plus: global-config: db-config: logic-delete-value: 1 # 逻辑已删除值(默认为 1) logic-not-delete-value: 0 # 逻辑未删除值(默认为 0)
3.@TableLogic
-
实体类字段上加上
@TableLogic注解@Data public class User { @TableId(type = IdType.AUTO) private Long id; private String name; @TableField(select = false) private Integer age; @TableField(value = "uemail") private String email; @TableLogic private Integer deleted; }
4.测试
-
测试删除
@Test public void testLogicDeleted(){ int ret = userMapper.deleteById(3L); System.out.println("删除受影响行数为："+ret); } -
结果
==> Preparing: UPDATE user SET deleted=1 WHERE id=? AND deleted=0 ==> Parameters: 3(Long) <== Updates: 1 -
测试查询
@Test public void testLogicDeletedSelect(){ QueryWrapper<User> wrapper = new QueryWrapper<>(); List<User> user = userMapper.selectList(wrapper); System.out.println(user); } -
结果
==> Preparing: SELECT id,name,uemail AS email,deleted FROM user WHERE deleted=0 ==> Parameters: <== Total: 3 -
数据库结果
二、通用枚举
解决了繁琐的配置，让 mybatis 优雅的使用枚举属性！ 从 3.5.2 版本开始只需完成
步骤1: 声明通用枚举属性即可使用
1.修改表结构
-
添加性别字段
ALTER TABLE user ADD column `sex` int DEFAULT '1' COMMENT '1-男 0-女';
2.声明通用枚举属性
-
枚举
public enum SexEnum implements IEnum<Integer> { MAN(1, "男"), WOMAN(0, "女"); private int value; private String desc; SexEnum(int value,String desc){ this.value = value; this.desc = desc; } @Override public Integer getValue() { return this.value; } @Override public String toString() { return this.desc; } }
3.实体属性使用枚举类型
-
实体属性添加枚举类型
@Data public class User { @TableId(type = IdType.AUTO) private Long id; private String name; @TableField(select = false) private Integer age; @TableField(value = "uemail") private String email; @TableLogic private Integer deleted; private SexEnum sex; }
4.额外补充
如果是3.5.2版本之后的不需要配置了
-
之前版本的按如下配置
mybatis-plus: # 支持统配符 * 或者 ; 分割 typeEnumsPackage: com.baomidou.springboot.entity.enums -
序列化给前端按如下两种方式都可以实现
4.1Fastjson
-
添加如下注解
@JSONField(serialzeFeatures= SerializerFeature.WriteEnumUsingToString) private UserStatus status;
4.2 jackson
-
添加如下注解
@JsonValue //标记响应json值 private final int code;
5.测试
-
测试
@Test public void testEnum(){ User entity = new User(); entity.setEmail("erew"); entity.setAge(19); entity.setName("小红"); entity.setSex(SexEnum.MAN); int insert = userMapper.insert(entity); System.out.println("受影响行数为："+insert); } -
结果
==> Preparing: INSERT INTO user ( name, age, uemail, sex ) VALUES ( ?, ?, ?, ? ) ==> Parameters: 小红(String), 19(Integer), erew(String), 1(Integer) <== Updates: 1 -
数据库结果
三、自动填充功能
开发中，比如
插入数据的时候需要插入创建时间
更新数据的时候需要添加更新时间
1.修改表结构
-
修改表结构
CREATE TABLE `user` ( `id` bigint NOT NULL AUTO_INCREMENT COMMENT '主键ID', `name` varchar(30) DEFAULT NULL COMMENT '姓名', `age` int DEFAULT NULL COMMENT '年龄', `uemail` varchar(128) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci DEFAULT NULL COMMENT '邮箱', `deleted` int DEFAULT '0' COMMENT '删除与否', `sex` int DEFAULT '1' COMMENT '性别', `create_time` datetime DEFAULT NULL COMMENT '创建时间', `update_time` datetime DEFAULT NULL COMMENT '更新时间', PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;
2.@TableField
-
FieldFill
public enum FieldFill { DEFAULT,//不处理 INSERT,//插入查出 UPDATE,//更新处理 INSERT_UPDATE;//插入和更新处理 } -
添加字段
@TableField(value = "create_time",fill = FieldFill.INSERT) private Date createTime; @TableField(value = "update_time",fill = FieldFill.UPDATE) private Date updateTime;
3.自定义实现类 MyMetaObjectHandler
-
自定义实现类 MyMetaObjectHandler
@Slf4j @Component public class MyMetaObjectHandler implements MetaObjectHandler { @Override public void insertFill(MetaObject metaObject) { log.info("start insert fill ...."); setFieldValByName("createTime",new Date(),metaObject); } @Override public void updateFill(MetaObject metaObject) { log.info("start update fill ...."); setFieldValByName("updateTime",new Date(),metaObject); } }
4.测试
-
测试插入操作
@Test public void testFillInsert(){ User entity = new User(); entity.setEmail("erew"); entity.setAge(19); entity.setName("小红"); entity.setSex(SexEnum.MAN); int insert = userMapper.insert(entity); System.out.println("受影响行数为："+insert); } -
测试结果
==> Preparing: INSERT INTO user ( name, age, uemail, sex, create_time ) VALUES ( ?, ?, ?, ?, ? ) ==> Parameters: 小红(String), 19(Integer), erew(String), 1(Integer), 2022-12-03 11:34:41.169(Timestamp) <== Updates: 1 -
测试更新操作
@Test public void testFillUpdate(){ User entity = new User(); entity.setId(15L); entity.setEmail("erew"); entity.setAge(19); entity.setName("小红"); entity.setSex(SexEnum.MAN); int insert = userMapper.updateById(entity); System.out.println("受影响行数为："+insert); } -
测试结果
==> Preparing: UPDATE user SET name=?, age=?, uemail=?, sex=?, update_time=? WHERE id=? AND deleted=0 ==> Parameters: 小红(String), 19(Integer), erew(String), 1(Integer), 2022-12-03 11:37:10.716(Timestamp), 15(Long) <== Updates: 1 -
数据库结果
四、SQL注入器
1.SQL注入的原理分析
MyBatisPlus 是使用 ISqlInjector 接口负责SQL注入工作
-
具体实现注入
public void inspectInject(MapperBuilderAssistant builderAssistant, Class<?> mapperClass) { Class<?> modelClass = ReflectionKit.getSuperClassGenericType(mapperClass, Mapper.class, 0); if (modelClass != null) { String className = mapperClass.toString(); Set<String> mapperRegistryCache = GlobalConfigUtils.getMapperRegistryCache(builderAssistant.getConfiguration()); if (!mapperRegistryCache.contains(className)) { TableInfo tableInfo = TableInfoHelper.initTableInfo(builderAssistant, modelClass); List<AbstractMethod> methodList = this.getMethodList(mapperClass, tableInfo); if (CollectionUtils.isNotEmpty(methodList)) { methodList.forEach((m) -> { m.inject(builderAssistant, mapperClass, modelClass, tableInfo); }); } else { this.logger.debug(mapperClass.toString() + ", No effective injection method was found."); } mapperRegistryCache.add(className); } } } -
实际的实现代码
methodList.forEach((m) -> { m.inject(builderAssistant, mapperClass, modelClass, tableInfo); }); -
m.inject 调用具体方法
this.injectMappedStatement(mapperClass, modelClass, tableInfo); -
最终具体的执行就是自己定义的类
2.扩充BaseMapper中方法
2.1编写自己的BaseMapper
-
编写MyBaseMapper
public interface MyBaseMapper<T> extends BaseMapper<T> { List<T> listAll(); } -
需要用到的mapper 直接继承即可
@Repository public interface UserMapper extends MyBaseMapper<User> { }
2.2编写MySqlInjector
-
MySqlInjector
@Component public class MySqlInjector extends DefaultSqlInjector { @Override public List<AbstractMethod> getMethodList(Class<?> mapperClass, TableInfo tableInfo) { //默认的mybatis-plus 的注入方法 List<AbstractMethod> methodList = super.getMethodList(mapperClass, tableInfo); //添加自己的 listAll 类 methodList.add(new ListAll()); return methodList; } }
2.3编写ListAll类
-
创建ListAll 类
public class ListAll extends AbstractMethod { @Override public MappedStatement injectMappedStatement(Class<?> mapperClass, Class<?> modelClass, TableInfo tableInfo) { String sqlMethod = "listAll"; String sql = "select * from "+tableInfo.getTableName(); SqlSource sqlSource = this.languageDriver.createSqlSource(this.configuration, sql, modelClass); return this.addSelectMappedStatementForTable(mapperClass,sqlMethod,sqlSource,tableInfo); } }
2.4测试
-
测试
@Test public void testInjector(){ List<User> users = userMapper.listAll(); System.out.println(users); } -
结果
==> Preparing: select * from user ==> Parameters: <== Total: 13
五、插件
1.拦截器核心代码
MybatisPlusInterceptor
该插件是核心插件,目前代理了
Executor#query和Executor#update和StatementHandler#prepare方法
-
拦截器核心代码
@Intercepts({ @Signature(type = StatementHandler.class, method = "prepare", args = {Connection.class, Integer.class}), }) @Component public class MyInterceptor implements Interceptor { @Override public Object intercept(Invocation invocation) throws Throwable { System.out.println("拦截前操作"); //做拦截操作 return invocation.proceed(); } @Override public Object plugin(Object target) { System.out.println("装配插件"); //装配插件 return Plugin.wrap(target, this); } @Override public void setProperties(Properties properties) { System.out.println("设置属性"); //属性设置 } } -
交给容器管理即可实现拦截操作
2.分页插件
-
使用
@Configuration @MapperScan("cn.sycoder.mapper") public class MybatisPlusConfig { @Bean public MybatisPlusInterceptor mybatisPlusInterceptor() { MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor(); interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL)); return interceptor; } }
3.乐观锁插件
OptimisticLockerInnerInterceptor
当要更新一条记录的时候，希望这条记录没有被别人更新
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
3.1乐观锁补充
-
在数据库增加一个 version 字段来管理数据，假设没有其它人操作过这条数据，先读取本条数据的version,然后再修改的时候，判断之前拿出来的version 和现在的version是否一致，如果不一致，则表示被人操作过，不能够正常实现更新
-
sql 演示
update user set age = 123123,version = version+1 where id = 16 and version = 0;
3.2添加乐观锁配置
-
添加配置
@Configuration @MapperScan("cn.sycoder.mapper") public class MybatisPlusConfig { @Bean public MybatisPlusInterceptor mybatisPlusInterceptor() { MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor(); interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL)); interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor()); return interceptor; } }
3.3修改表结构
-
表结构
CREATE TABLE `user` ( `id` bigint NOT NULL AUTO_INCREMENT COMMENT '主键ID', `name` varchar(30) DEFAULT NULL COMMENT '姓名', `age` int DEFAULT NULL COMMENT '年龄', `uemail` varchar(128) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci DEFAULT NULL COMMENT '邮箱', `deleted` int DEFAULT '0' COMMENT '删除与否', `sex` int DEFAULT '1' COMMENT '性别', `create_time` datetime DEFAULT NULL COMMENT '创建时间', `update_time` datetime DEFAULT NULL COMMENT '更新时间', `version` int DEFAULT NULL COMMENT '乐观锁控制', PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=17 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;
3.4添加 version 字段
-
实体添加字段
@Version private Integer version;
3.5测试
-
测试乐观锁
@Test public void testVersion(){ User user = userMapper.selectById(16L); user.setName("云哥666"); int count = userMapper.updateById(user); System.out.println("受影响行数："+count); } -
结果
==> Preparing: UPDATE user SET name=?, uemail=?, sex=?, create_time=?, update_time=?, version=? WHERE id=? AND version=? AND deleted=0 ==> Parameters: 云哥666(String), sy@qq.com(String), 1(Integer), 2022-12-03 11:34:41.0(Timestamp), 2022-12-03 17:44:05.425(Timestamp), 3(Integer), 16(Long), 2(Integer) <== Updates: 1
4.防全表更新与删除插件
BlockAttackInnerInterceptor
针对 update 和 delete 语句 作用: 阻止恶意的全表更新删除
4.1配置拦截器
-
配置
@Configuration @MapperScan("cn.sycoder.mapper") public class MybatisPlusConfig { @Bean public MybatisPlusInterceptor mybatisPlusInterceptor() { MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor(); interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL)); interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor()); interceptor.addInnerInterceptor(new BlockAttackInnerInterceptor()); return interceptor; } }
4.2测试
-
测试全表删除
@Test public void testDeleteAll(){ QueryWrapper<User> wrapper = new QueryWrapper<>(); int count = userMapper.delete(wrapper); System.out.println("受影响行数："+count); }
六、代码生成器
- 简化开发流程，提高开发效率，让程序写很少的代码就能实现开发
1.创建 mybatis-plus-02 模块
- 任选创建方式创建
2.添加依赖
-
依赖
<parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.7.5</version> </parent> <dependencies> <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> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-boot-starter</artifactId> <version>3.5.2</version> </dependency> <dependency> <groupId>com.baomidou</groupId> <artifactId>mybatis-plus-generator</artifactId> <version>3.5.2</version> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-freemarker</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.freemarker</groupId> <artifactId>freemarker</artifactId> <version>2.3.31</version> </dependency> <dependency> <groupId>io.springfox</groupId> <artifactId>springfox-swagger-ui</artifactId> <version>2.10.1</version> </dependency> <dependency> <groupId>io.springfox</groupId> <artifactId>springfox-swagger2</artifactId> <version>2.10.1</version> </dependency> </dependencies>
3.使用
-
使用
public static void main(String[] args) { FastAutoGenerator.create("jdbc:mysql://localhost:3306/mybatis-plus", "root", "123456") .globalConfig(builder -> { builder.author("sy") // 设置作者 .enableSwagger() // 开启 swagger 模式 .fileOverride() // 覆盖已生成文件 .outputDir("F:\\03-Spring\\MyBatisPlus\\homework\\mybatis-plus-02\\src\\main\\java\\"); // 指定输出目录 }) .packageConfig(builder -> { builder.parent("cn") // 设置父包名 .moduleName("sycoder") // 设置父包模块名 .pathInfo(Collections.singletonMap(OutputFile.xml, "F:\\03-Spring\\MyBatisPlus\\homework\\mybatis-plus-02\\src\\main\\resources\\cn\\sycoder")); // 设置mapperXml生成路径 }) .strategyConfig(builder -> { builder.addInclude("user"); // 设置需要生成的表名 // .addTablePrefix("t_", "c_"); // 设置过滤表前缀 }) .templateEngine(new FreemarkerTemplateEngine()) // 使用Freemarker引擎模板，默认的是Velocity引擎模板 .execute(); }
