SpringBoot后端进阶实战教程<\/h1>

一、删除员工功能实现<\/h2>

1. 核心知识点<\/h3>

参数接收方式对比：<\/strong><\/p>

列表参数接收：需要使用@RequestParam<\/code>注解<\/li> <\/ul> @DeleteMapping<\/span> <\/span><\/span>public<\/span> Result delete<\/span>(<\/span>@RequestParam<\/span> List<<\/span>Integer><\/span> ids)<\/span> {<\/span> <\/span><\/span> \/\/ 列表传递需要额外加注解 <\/span><\/span><\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre> 数组参数接收：直接对应参数名即可<\/li> <\/ul> @DeleteMapping<\/span> <\/span><\/span>public<\/span> Result delete<\/span>(<\/span>Integer[]<\/span> ids)<\/span> {<\/span> <\/span><\/span> \/\/ 数组传递直接对应名字 <\/span><\/span><\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>2. 完整实现代码<\/h3> Controller层：<\/strong><\/p> @DeleteMapping<\/span> <\/span><\/span>public<\/span> Result delete<\/span>(<\/span>@RequestParam<\/span> List<<\/span>Integer><\/span> ids)<\/span> {<\/span> <\/span><\/span> log.<\/span>info<\/span>(<\/span>"删除员工,参数:{}"<\/span>,<\/span> ids);<\/span> <\/span><\/span> empService.<\/span>delete<\/span>(<\/span>ids);<\/span> <\/span><\/span> return<\/span> Result.<\/span>success<\/span>();<\/span> <\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>Service层：<\/strong><\/p> @Override<\/span> <\/span><\/span>public<\/span> void<\/span> delete<\/span>(<\/span>List<<\/span>Integer><\/span> ids)<\/span> {<\/span> <\/span><\/span> \/\/ 删除员工基本信息 <\/span><\/span><\/span><\/span> empMapper.<\/span>deleteBatch<\/span>(<\/span>ids);<\/span> <\/span><\/span> \/\/ 删除员工经历信息 <\/span><\/span><\/span><\/span> empExprMapper.<\/span>deleteBatch<\/span>(<\/span>ids);<\/span> <\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>Mapper层SQL实现：<\/strong><\/p> 删除员工经历表数据：<\/p> <delete<\/span> id=<\/span>"deleteBatch"<\/span>><\/span> <\/span><\/span> delete from emp_expr <\/span><\/span> where emp_id in <\/span><\/span> <foreach<\/span> collection=<\/span>"ids"<\/span> item=<\/span>"id"<\/span> open=<\/span>"("<\/span> close=<\/span>")"<\/span> separator=<\/span>","<\/span>><\/span> <\/span><\/span> #{id} <\/span><\/span> <\/foreach><\/span> <\/span><\/span><\/delete><\/span> <\/span><\/span><\/code><\/pre>删除员工主表数据：<\/p> <delete<\/span> id=<\/span>"deleteBatch"<\/span>><\/span> <\/span><\/span> delete from emp <\/span><\/span> where id in <\/span><\/span> <foreach<\/span> collection=<\/span>"ids"<\/span> item=<\/span>"id"<\/span> open=<\/span>"("<\/span> close=<\/span>")"<\/span> separator=<\/span>","<\/span>><\/span> <\/span><\/span> #{id} <\/span><\/span> <\/foreach><\/span> <\/span><\/span><\/delete><\/span> <\/span><\/span><\/code><\/pre>3. MyBatis动态SQL标签说明<\/h3> <foreach><\/code>：遍历集合参数<\/li> collection="ids"<\/code>：指定要遍历的集合参数名<\/li> item="id"<\/code>：定义当前遍历元素的变量名<\/li> open="(" close=")"<\/code>：定义循环开始和结束时的字符串<\/li> separator=","<\/code>：定义元素之间的分隔符<\/li> <\/ul> 二、修改员工功能实现<\/h2> 1. 复杂结果集手动映射<\/h3> 适用场景：<\/strong> 当查询结果类型太复杂，无法通过自动映射完成时，需要手动定义ResultMap。<\/p> Mapper查询实现：<\/strong><\/p> <select<\/span> id=<\/span>"getinfo"<\/span> resultMap=<\/span>"empResultMap"<\/span>><\/span> <\/span><\/span> <\/span> <\/span><\/span><\/select><\/span> <\/span><\/span><\/code><\/pre>ResultMap定义详解：<\/strong><\/p> <resultMap<\/span> id=<\/span>"empResultMap"<\/span> type=<\/span>"com.itheima.pojo.Emp"<\/span>><\/span> <\/span><\/span> <\/span> <\/span><\/span> <id<\/span> column=<\/span>"id"<\/span> property=<\/span>"id"<\/span>\/><\/span> <\/span><\/span> <\/span><\/span> <\/span> <\/span><\/span> <result<\/span> column=<\/span>"username"<\/span> property=<\/span>"username"<\/span>\/><\/span> <\/span><\/span> <result<\/span> column=<\/span>"password"<\/span> property=<\/span>"password"<\/span>\/><\/span> <\/span><\/span> <\/span><\/span> <\/span> <\/span><\/span> <collection<\/span> property=<\/span>"exprList"<\/span> ofType=<\/span>"com.itheima.pojo.EmpExpr"<\/span>><\/span> <\/span><\/span> <\/span> <\/span><\/span> <id<\/span> column=<\/span>"ee_id"<\/span> property=<\/span>"id"<\/span>\/><\/span> <\/span><\/span> <\/span> <\/span><\/span> <result<\/span> column=<\/span>"begin"<\/span> property=<\/span>"begin"<\/span>\/><\/span> <\/span><\/span> <\/span> <\/span><\/span> <\/collection><\/span> <\/span><\/span><\/resultMap><\/span> <\/span><\/span><\/code><\/pre>2. ResultMap映射规则<\/h3> <id><\/code>标签<\/strong>：用于映射主键字段，提高识别效率<\/li> <result><\/code>标签<\/strong>：用于映射普通字段<\/li> <collection><\/code>标签<\/strong>：用于映射一对多关系的集合属性<\/li> ofType<\/code>属性<\/strong>：指定集合中元素的类型<\/li> <\/ul> 3. 更新语句动态判断<\/h3> Mapper更新实现：<\/strong><\/p> <mapper<\/span> namespace=<\/span>"com.itheima.mapper.EmpMapper"<\/span>><\/span> <\/span><\/span> <update<\/span> id=<\/span>"update"<\/span>><\/span> <\/span><\/span> update emp <\/span><\/span> <set><\/span> <\/span><\/span> <if<\/span> test=<\/span>"username != null"<\/span>><\/span>username = #{username},<\/if><\/span> <\/span><\/span> <if<\/span> test=<\/span>"password != null"<\/span>><\/span>password = #{password},<\/if><\/span> <\/span><\/span> <\/span> <\/span><\/span> <\/set><\/span> <\/span><\/span> where id = #{id} <\/span><\/span> <\/update><\/span> <\/span><\/span><\/mapper><\/span> <\/span><\/span><\/code><\/pre>4. 动态SQL标签说明<\/h3> <set><\/code>标签<\/strong>：自动处理SET语句中的逗号，避免末尾多余逗号<\/li> <if><\/code>标签<\/strong>：条件判断，只有test条件为true时才会包含对应的SQL片段<\/li> 动态字段更新<\/strong>：只更新非空的字段，提高更新效率<\/li> <\/ul> 三、全局异常管理器<\/h2> 1. 异常处理机制<\/h3> SpringBoot全局异常处理的核心是统一处理控制器层抛出的异常，提供一致的错误响应格式。<\/p> 2. 基础异常处理结构<\/h3> @ControllerAdvice<\/span> <\/span><\/span>public<\/span> class<\/span> GlobalExceptionHandler<\/span> {<\/span> <\/span><\/span> <\/span><\/span> @ExceptionHandler<\/span>(<\/span>Exception.<\/span>class<\/span>)<\/span> <\/span><\/span> @ResponseBody<\/span> <\/span><\/span> public<\/span> Result handleException<\/span>(<\/span>Exception e)<\/span> {<\/span> <\/span><\/span> \/\/ 统一的异常处理逻辑 <\/span><\/span><\/span><\/span> return<\/span> Result.<\/span>error<\/span>(<\/span>"系统异常，请稍后重试"<\/span>);<\/span> <\/span><\/span> }<\/span> <\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>3. 具体异常类型处理<\/h3> \/\/ 处理业务异常 <\/span><\/span><\/span><\/span>@ExceptionHandler<\/span>(<\/span>BusinessException.<\/span>class<\/span>)<\/span> <\/span><\/span>public<\/span> Result handleBusinessException<\/span>(<\/span>BusinessException e)<\/span> {<\/span> <\/span><\/span> log.<\/span>error<\/span>(<\/span>"业务异常：{}"<\/span>,<\/span> e.<\/span>getMessage<\/span>());<\/span> <\/span><\/span> return<\/span> Result.<\/span>error<\/span>(<\/span>e.<\/span>getMessage<\/span>());<\/span> <\/span><\/span>}<\/span> <\/span><\/span> <\/span><\/span>\/\/ 处理参数校验异常 <\/span><\/span><\/span><\/span>@ExceptionHandler<\/span>(<\/span>MethodArgumentNotValidException.<\/span>class<\/span>)<\/span> <\/span><\/span>public<\/span> Result handleValidationException<\/span>(<\/span>MethodArgumentNotValidException e)<\/span> {<\/span> <\/span><\/span> String errorMessage =<\/span> e.<\/span>getBindingResult<\/span>()<\/span> <\/span><\/span> .<\/span>getFieldErrors<\/span>()<\/span> <\/span><\/span> .<\/span>stream<\/span>()<\/span> <\/span><\/span> .<\/span>map<\/span>(<\/span>FieldError::<\/span>getDefaultMessage)<\/span> <\/span><\/span> .<\/span>collect<\/span>(<\/span>Collectors.<\/span>joining<\/span>(<\/span>", "<\/span>));<\/span> <\/span><\/span> return<\/span> Result.<\/span>error<\/span>(<\/span>"参数校验失败: "<\/span> +<\/span> errorMessage);<\/span> <\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>4. 设置具体提示信息<\/h3> 通过自定义异常类来传递具体的错误信息：<\/p> public<\/span> class<\/span> BusinessException<\/span> extends<\/span> RuntimeException {<\/span> <\/span><\/span> private<\/span> String code;<\/span> <\/span><\/span> private<\/span> String message;<\/span> <\/span><\/span> <\/span><\/span> public<\/span> BusinessException<\/span>(<\/span>String message)<\/span> {<\/span> <\/span><\/span> super<\/span>(<\/span>message);<\/span> <\/span><\/span> this<\/span>.<\/span>message<\/span> =<\/span> message;<\/span> <\/span><\/span> }<\/span> <\/span><\/span> <\/span><\/span> \/\/ getter and setter <\/span><\/span><\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>四、员工信息统计功能<\/h2> 1. 统计功能知识点<\/h3> 使用SQL聚合函数进行数据统计<\/li> 结果集映射到自定义DTO对象<\/li> 多维度数据统计展示<\/li> <\/ul> 2. 职位统计实现<\/h3> Mapper接口定义：<\/strong><\/p> public<\/span> interface<\/span> EmpMapper<\/span> {<\/span> <\/span><\/span> List<<\/span>PositionStats><\/span> countByPosition<\/span>();<\/span> <\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>统计DTO对象：<\/strong><\/p> public<\/span> class<\/span> PositionStats<\/span> {<\/span> <\/span><\/span> private<\/span> String position;<\/span> \/\/ 职位名称 <\/span><\/span><\/span><\/span> private<\/span> Integer count;<\/span> \/\/ 该职位人数 <\/span><\/span><\/span><\/span> \/\/ getter and setter <\/span><\/span><\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>SQL实现：<\/strong><\/p> <select<\/span> id=<\/span>"countByPosition"<\/span> resultType=<\/span>"com.itheima.dto.PositionStats"<\/span>><\/span> <\/span><\/span> select position, count(*) as count <\/span><\/span> from emp <\/span><\/span> where position is not null <\/span><\/span> group by position <\/span><\/span> order by count desc <\/span><\/span><\/select><\/span> <\/span><\/span><\/code><\/pre>3. 性别统计实现<\/h3> Mapper接口：<\/strong><\/p> List<<\/span>GenderStats><\/span> countByGender<\/span>();<\/span> <\/span><\/span><\/code><\/pre>统计SQL：<\/strong><\/p> <select<\/span> id=<\/span>"countByGender"<\/span> resultType=<\/span>"com.itheima.dto.GenderStats"<\/span>><\/span> <\/span><\/span> select <\/span><\/span> gender, <\/span><\/span> count(*) as count, <\/span><\/span> round(count(*) * 100.0 \/ (select count(*) from emp), 2) as percentage <\/span><\/span> from emp <\/span><\/span> where gender is not null <\/span><\/span> group by gender <\/span><\/span><\/select><\/span> <\/span><\/span><\/code><\/pre>五、最佳实践和注意事项<\/h2> 1. 批量操作性能优化<\/h3> 使用<foreach><\/code>标签时，建议单次批量操作数量控制在1000条以内<\/li> 大数据量批量删除建议分批次进行<\/li> <\/ul> 2. 事务管理<\/h3> @Service<\/span> <\/span><\/span>@Transactional<\/span> <\/span><\/span>public<\/span> class<\/span> EmpService<\/span> {<\/span> <\/span><\/span> <\/span><\/span> @Override<\/span> <\/span><\/span> @Transactional<\/span>(<\/span>rollbackFor =<\/span> Exception.<\/span>class<\/span>)<\/span> <\/span><\/span> public<\/span> void<\/span> delete<\/span>(<\/span>List<<\/span>Integer><\/span> ids)<\/span> {<\/span> <\/span><\/span> \/\/ 删除操作需要在同一事务中 <\/span><\/span><\/span><\/span> empMapper.<\/span>deleteBatch<\/span>(<\/span>ids);<\/span> <\/span><\/span> empExprMapper.<\/span>deleteBatch<\/span>(<\/span>ids);<\/span> <\/span><\/span> }<\/span> <\/span><\/span>}<\/span> <\/span><\/span><\/code><\/pre>3. 日志记录规范<\/h3> 关键操作必须记录日志<\/li> 日志内容要包含必要的业务参数<\/li> 使用SLF4J的占位符方式记录日志<\/li> <\/ul> 4. 安全考虑<\/h3> 删除操作前进行权限校验<\/li> 重要数据采用逻辑删除而非物理删除<\/li> 操作日志要完整记录<\/li> <\/ul> 本教程详细介绍了SpringBoot后端开发中的核心功能实现，涵盖了数据操作、异常处理、统计功能等关键知识点，为后端开发提供了完整的技术解决方案。<\/p>