【学习笔记】mybatis-plus轻松入门(库存)

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Mybatis-plus入门

官网:baomidou.com/

引入依赖:

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.4.1</version>
</dependency>

不要同时引入mybatis和mybatis-plus。

连接配置

spring:
  datasource:
    url: jdbc:mysql://xx.xx.xx.xx:3306/cc?characterEncoding=utf-8&serverTimezone=GMT%2B8&useSSL=false&useUnicode=true
    #mysql8版本必须要配置时区
    username: root
    password: xxx
    type: com.alibaba.druid.pool.DruidDataSource #制定了数据源的类型,屏蔽掉了官方自动配置的数据源
    driver-class-name: com.mysql.cj.jdbc.Driver

不用手写mapper文件中的内容

直接继承basemapper类就可以使用全部的crud操作

配置日志

mybatis-pluss.confurtion.log-iml=org.apache.ibatis.logging.stdout.StdOutImpl
主键生成策略(主键没有自增insert填充id):

雪花算法:自动生成也全球唯一的id

解决:@tableId(type = ==idType=AUTO==) 数据库主键设置自增即可。

idType解释

idType=input:手动输入。为输入值

none:没有主键

创建时间,更新时间

1.数据库操作

新建两个字段,,设置默认值为CURRENT_TIMESTAMP,相当于新建触发器!增加操作的时间由于没插入时间,触发器启动,自动设置为默认值。更新也是。

2.代码操作

@TableFiled(fill = FiledFill.INSERT)(插入的时候填充)

@TableFiled(fill = FiledFill.INSERT_UPDATE)(更新的时候填充)

**
 * 自动填充处理器
 */
@Component
@Slf4j
public class MyMetaObjectHandler implements MetaObjectHandler {
    //插入时候的填充策略
    @Override
    public void insertFill(MetaObject metaObject) {
        this.setFieldValByName("createTime", new Date().getTime(), metaObject);
        this.setFieldValByName("updateTime", new Date().getTime(), metaObject);
    }
    //更新时候的填充策略
    @Override
    public void updateFill(MetaObject metaObject) {
        this.setFieldValByName("updateTime", new Date().getTime(), metaObject);
    }
}
 @Test
    public void test() {
        Customer customer = new Customer();
        customer.setName("sjfl");
        customer.setBirth(new Date());
        customer.setEmail("djsa.com");
        int insert = userMapper.insert(customer);
        System.out.println(customer);
    }

    @Test
    public void test1() {
        Customer customer = new Customer();
        customer.setId(69);
        customer.setName("sjfl");
        customer.setBirth(new Date());
        customer.setEmail("dsafewreq.com");
        int insert = userMapper.updateById(customer);
        System.out.println(customer);
    }
}
@Data
@NoArgsConstructor
@ToString
@AllArgsConstructor
@TableName("customers") //指定表名
public class Customer {
    @TableId(type = IdType.AUTO)
    private Integer id;
    private String name;
    private String email;
    private Date birth;
    @TableField(exist = false) //字段不存在数据表中
    private String picture;
    @TableField(fill = FieldFill.INSERT)
    private Date createTime;
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private Date updateTime;
}

乐观锁

1.数据库中增加字段

2.实体类中添加对应字段

@version
private Integer version;

3.注册组件

@Configuration
@EnableTransactionManagement
@MapperScan("com.zero.dao")
public class MyBatisPlusVersion {
    //注册乐观锁插件
   @Bean
    public MybatisPlusInterceptor optimisticLockerInnerInterceptor(){
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
        return interceptor;
    }
}

@Test
    public void test2() {
        final Customer customer = userMapper.selectById(68);
        customer.setName("chengli");

    final Customer customer1 = userMapper.selectById(68);
    customer1.setName("tst");
    userMapper.updateById(customer1);


    userMapper.updateById(customer);

//结果为线程1 更新事变,因为获取的版本和更新时候的版本不一致,所以失败
    }

逻辑删除

在表中存储一个deleted字段,然后在实体类中增加字段

@Tablelogical添加注解

然胡在配置文件中设置

mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl # 开启sql日志
  global-config:
    db-config:
      logic-delete-value: 1 #配置逻辑删除
      logic-not-delete-value: 0

然后测试就行了。以后所有的增删改查都会带上删除字段对应没删除

条件构造器

用于处理复杂SQL

@Test
public void Test() {
    final QueryWrapper<Customer> objectQueryWrapper = new QueryWrapper<>();
    objectQueryWrapper.isNotNull("photo")
            .le("birth", new Date());
    userMapper.selectList(objectQueryWrapper).forEach(System.out::println);

}
@Test
public void test5() {
    final QueryWrapper<Customer> wrapper = new QueryWrapper<>();
    wrapper.inSql("id", "select id from customers where id < 3")
            .orderByDesc("id" );
    userMapper.selectList(wrapper).forEach(System.out::println);
}

代码生成器

引入依赖以及相关mybatis的配置

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-generator</artifactId>
    <version>3.4.1</version>
</dependency>
<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.4.1</version>
</dependency>

开发配置:

自动数据库字段

@Component
@Slf4j
public class MyMetaObjectHandler implements MetaObjectHandler {
    //插入时候的填充策略
    @Override
    public void insertFill(MetaObject metaObject) {
        this.setFieldValByName("createTime", new Date(), metaObject);
        this.setFieldValByName("updateTime", new Date(), metaObject);
    }
    //更新时候的填充策略
    @Override
    public void updateFill(MetaObject metaObject) {
        this.setFieldValByName("updateTime", new Date(), metaObject);
    }
}

mybatisPlus插件

@Configuration
@EnableTransactionManagement
@MapperScan("com.zero.dao")
public class MyBatisPlusConfig {
    //注册乐观锁插件
    @Bean
    public MybatisPlusInterceptor optimisticLockerInnerInterceptor(){
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new OptimisticLockerInnerInterceptor());
        return interceptor;
    }
    //分页插件
    @Bean
    public MybatisPlusInterceptor paginationInterceptor() {
        MybatisPlusInterceptor mybatisPlusInterceptor = new MybatisPlusInterceptor();
        //分页拦截器
        PaginationInnerInterceptor paginationInnerInterceptor = new PaginationInnerInterceptor();
        paginationInnerInterceptor.setOverflow(true);//溢出的时候是否调回首页
        paginationInnerInterceptor.setMaxLimit(-1L);//限制每页最大条数,-1不限
        mybatisPlusInterceptor.addInnerInterceptor(paginationInnerInterceptor);
        return mybatisPlusInterceptor;
    }

    //注册逻辑删除组件
//    @Bean
//    public ISqlInjector sqlInjector() {
//        return new LogicSqlInjector();
//    }
}
//高版本不用逻辑删除组件,需要配置yml文件:
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl # 开启sql日志
  global-config:
    db-config:
      logic-delete-value: 1 #配置逻辑删除
      logic-not-delete-value: 0
package com.example.lostfound;

import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.annotation.FieldFill;
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.NamingStrategy;

import java.util.ArrayList;

/**
 * @Author Zero
 * @Date 2021/8/10 23:42
 * @Since 1.8
 * @Description
 **/
public class MyGenerator {
    public static void main(String[] args) {
        // 代码生成器
        AutoGenerator mpg = new AutoGenerator();

        // 全局配置
        GlobalConfig gc = new GlobalConfig();
        String projectPath = System.getProperty("user.dir"); //当前项目路径
        gc.setOutputDir(projectPath + "/src/main/java");
        gc.setAuthor("zero");
        gc.setOpen(false); //是否打开资源管理器
        gc.setSwagger2(true); //实体属性 Swagger2 注解
        gc.setFileOverride(false);//是否覆盖
        gc.setServiceName("%sService");//去掉service的I前缀
        mpg.setGlobalConfig(gc);

        // 数据源配置
        DataSourceConfig dsc = new DataSourceConfig();
        dsc.setUrl("jdbc:mysql://82.157.191.65:3600/lost_found?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai&useSSL=false");
        // dsc.setSchemaName("public");
        dsc.setDriverName("com.mysql.cj.jdbc.Driver");
        dsc.setUsername("root");
        dsc.setPassword("chl252599");
        dsc.setDbType(DbType.MYSQL);//设置数据库为MySQL类型
        mpg.setDataSource(dsc);

        // 包配置
        PackageConfig pc = new PackageConfig();
        //pc.setModuleName(scanner("模块名"));
        pc.setModuleName("lostfound");
        pc.setParent("com.example");//设置模块父路径
        pc.setEntity("entity");
        pc.setController("controller");

        pc.setMapper("mapper");
        pc.setService("service");
        pc.setServiceImpl("impl");
        mpg.setPackageInfo(pc);

        //策略配置
        StrategyConfig strategy = new StrategyConfig();
        strategy.setInclude("t_found_commont","t_found_thing","t_loss_commont","t_loss_thing","t_permission","t_user","t_user_permission");
        strategy.setNaming(NamingStrategy.underline_to_camel);//包开启驼峰命名
        strategy.setColumnNaming(NamingStrategy.underline_to_camel); //字段开启驼峰命名
        strategy.setEntityLombokModel(true);//自动了lombok
        strategy.setLogicDeleteFieldName("deleted");//设置逻辑删除
        //设置自动填充
        TableFill gmtCreate = new TableFill("last_login_time", FieldFill.INSERT);//插入填充
        final ArrayList<TableFill> tableFills = new ArrayList<>();
        tableFills.add(gmtCreate);
        strategy.setTableFillList(tableFills);
        //乐观锁
        //strategy.setVersionFieldName("version");
        strategy.setRestControllerStyle(true);//controller层设置rest风格
        strategy.setControllerMappingHyphenStyle(true);//开启controller访问下划线命名s
        mpg.setStrategy(strategy);
        mpg.execute();
    }


}