万字干货 一文搞定mybatis-plus 让开发效率翻倍（2）

乐观锁：1.先查询获得版本号 version = version+1
-- A
 update user set name = hyc, version = version+1\
   where id = 2 and vsersion=1
-- B如果b线程抢先完成，这个时候 vsersion =2 会导致A修改失败
  update user set name = hyc, version = version+1
   where id = 2 and vsersion=1

    @Version
    private int version;

//乐观锁成功的情况，单线程下，一定成功
    @Test
    void contextLoads2() {
        user user = new user();
        user.setId(1419289393067204614l);
        user.setAge(3);
        user.setName("保证我一路畅通无阻");
        user.setEmail("3132774018@qq.com");
        int result = usermapper.updateById(user);
        System.out.println(result);
        System.out.println(user);
    }
    //  模拟多线程，测试乐观锁，被抢先的情况
    @Test
    void contextLoads3() {
        user userSel = usermapper.selectById(1l);
        userSel.setId(1l);
        userSel.setAge(3);
        userSel.setName("保证我一路畅通无阻000");
        userSel.setEmail("3132774018@qq.com");
        user userSel1 = usermapper.selectById(1l);
        userSel1.setId(1l);
        userSel1.setAge(3);
        userSel1.setName("保证我一路畅通无阻111");
        userSel1.setEmail("3132774018@qq.com");
        int result1 = usermapper.updateById(userSel1);
        int result = usermapper.updateById(userSel);
    }
}

   @Bean
    public PaginationInterceptor paginationInterceptor() {
        PaginationInterceptor paginationInterceptor = new PaginationInterceptor();
        // 设置请求的页面大于最大页后操作， true调回到首页，false 继续请求  默认false
        // paginationInterceptor.setOverflow(false);
        // 设置最大单页限制数量，默认 500 条，-1 不受限制
        // paginationInterceptor.setLimit(500);
        // 开启 count 的 join 优化,只针对部分 left join
        paginationInterceptor.setCountSqlParser(new JsqlParserCountOptimize(true));
        return paginationInterceptor;
    }

//测试分页查询
    @Test
    void selectByPage(){
        //参数一：当前页，参数二：页面条数大小
        Page<user> page = new Page<>(1,5);
        usermapper.selectPage(page,null);
        page.getRecords().forEach(System.out::println);
        System.out.println(page.getTotal());
    }

//删除
    @Test
void deleteByid(){
        usermapper.deleteById(1l);
}
//批量按id删除
@Test
void deleteBybatchid(){
        usermapper.deleteBatchIds(Arrays.asList(1419289393067204612l,1419289393067204613l));
}
//根据map条件删除
@Test
void deleteBymapid(){
    HashMap<String, Object> map = new HashMap<>();
    map.put("id","1419289393067204614");
    usermapper.deleteByMap(map);
}

   //构建一个代码生成器对象
        AutoGenerator generator = new AutoGenerator();
        //配置策略
        //1.全局配置
        GlobalConfig gc = new GlobalConfig();
        String projectpath = System.getProperty("user.dir");//项目地址
        gc.setOutputDir(projectpath+"/src/main/java");
        gc.setAuthor("hyc");
        gc.setOpen(false);
        gc.setFileOverride(false);//是否覆盖
        gc.setServiceImplName("%sService");//接口前缀，不要
        gc.setIdType(IdType.ID_WORKER);//策略id
        gc.setDateType(DateType.ONLY_DATE);//时间类型
        gc.setSwagger2(true);//开启Swagger
        generator.setGlobalConfig(gc);
        //2.数据源配置
        DataSourceConfig dsc = new DataSourceConfig();
        dsc.setDriverName("com.mysql.cj.jdbc.Driver");
        dsc.setUsername("root");
        dsc.setPassword("root");
        dsc.setUrl("jdbc:mysql://localhost:3306/mybatis_plus?userSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=GMT%2B8");
        dsc.setDbType(DbType.MYSQL);//这只数据库
        generator.setDataSource(dsc);
        //3.包配置
        PackageConfig pc = new PackageConfig();
        pc.setModuleName("blog");
        pc.setParent("com.hyc");
        pc.setEntity("pojo");
        pc.setMapper("mapper");
        pc.setService("Service");
        pc.setController("controller");
        generator.setPackageInfo(pc);
        //策略配置
        StrategyConfig strategy = new StrategyConfig();
        strategy.setInclude("user");//配置映射的表名可以写很多个比如：user，role，region
        strategy.setNaming(NamingStrategy.underline_to_camel);//驼峰
        strategy.setColumnNaming(NamingStrategy.underline_to_camel);//数据库的名字转换
        strategy.setEntityLombokModel(true);//是否开启lombok
        strategy.setRestControllerStyle(true);
        //逻辑删除
        strategy.setLogicDeleteFieldName("deleted");
        //自动填充
        TableFill gmtcreate =new TableFill("create_time", FieldFill.INSERT);//再新增的时候填充
        TableFill gmtupd=new TableFill("update_time", FieldFill.INSERT_UPDATE);//再新增和更新的时候填充
        ArrayList<TableFill> tablefill = new ArrayList<>();
        tablefill.add(gmtcreate);
        tablefill.add(gmtupd);
        strategy.setTableFillList(tablefill);
        //乐观锁
        strategy.setVersionFieldName("version");//sersion叫变量
        strategy.setRestControllerStyle(true);//开启restful风格接口
        strategy.setControllerMappingHyphenStyle(true);//请求风格，localhost/v1/id_ps_..
        generator.setStrategy(strategy);
        generator.execute();