企业办公系统：2、MyBatis-Plus

一、MyBatis-Plus

官网：https://baomidou.com/

1、简介

MyBatis-Plus（简称 MP）是一个MyBatis的增强工具，在 MyBatis 的基础上只做增强不做改变，为简化开发、提高效率而生。

2、主要特点

• 无侵入：只做增强不做改变，引入它不会对现有工程产生影响，如丝般顺滑
• 强大的 CRUD 操作：内置通用 Mapper、通用 Service，仅仅通过少量配置即可实现单表大部分 CRUD 操作，更有强大的条件构造器，满足各类使用需求
• 支持 Lambda 形式调用：通过 Lambda 表达式，方便的编写各类查询条件，无需再担心字段写错
• 支持主键自动生成：支持多达 4 种主键策略（内含分布式唯一 ID 生成器 - Sequence），可自由配置，完美解决主键问题
• 内置代码生成器：采用代码或者 Maven 插件可快速生成 Mapper 、 Model 、 Service 、 Controller 层代码，支持模板引擎，更有超多自定义配置等您来使用
• 内置分页插件：基于 MyBatis 物理分页，开发者无需关心具体操作，配置好插件之后，写分页等同于普通 List 查询
• 分页插件支持多种数据库：支持 MySQL、MariaDB、Oracle、DB2、H2、HSQL、SQLite、Postgre、SQLServer 等多种数据库

3、依赖

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

二、MyBatis-Plus入门

前面介绍了MyBatis-Plus，当前就以角色管理为例讲解MyBatis-Plus的使用

1、配置文件

配置 MySQL 数据库的相关配置及Mybatis-Plus日志

application.yml

spring:application:name: service-oaprofiles:active: dev

application-dev.yml

server:port: 8800
mybatis-plus:configuration:log-impl: org.apache.ibatis.logging.stdout.StdOutImpl # 查看日志
spring:datasource:type: com.zaxxer.hikari.HikariDataSourcedriver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/survey-oa?serverTimezone=GMT%2B8&useSSL=false&characterEncoding=utf-8username: rootpassword: 123456

2、启动类

在 Spring Boot 启动类中添加 @MapperScan 注解，扫描 Mapper 文件夹：

package com.atsurvey;import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;/*** @Author tigerhhzz* @Date 2024 05 01 13 01**/@SpringBootApplication
//@EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})
@ComponentScan("com.atsurvey")
//@MapperScan("com.atsurvey.*.mapper")
@MapperScan("com.atsurvey.auth.mapper")
public class ServiceAuthApplication {public static void main(String[] args) {SpringApplication.run(ServiceAuthApplication.class, args);}}

3、实体类

已引入，实体类说明：

实体类注解详细文档：https://baomidou.com/pages/223848/

@TableName：表名注解，标识实体类对应的表

@TableId：主键注解，type = IdType.AUTO（数据库 ID 自增）

@TableField：字段注解（非主键）

@TableLogic：逻辑删除

package com.atsurvey.model.system;import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableName;
import com.atsurvey.model.base.BaseEntity;
import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;@Data
@ApiModel(description = "角色")
@TableName("sys_role")
public class SysRole extends BaseEntity {private static final long serialVersionUID = 1L;//@NotBlank(message = "角色名称不能为空")@ApiModelProperty(value = "角色名称")@TableField("role_name")private String roleName;@ApiModelProperty(value = "角色编码")@TableField("role_code")private String roleCode;@ApiModelProperty(value = "描述")@TableField("description")private String description;}

4、添加Mapper类

package com.atsurvey.auth.mapper;import com.atsurvey.model.system.SysRole;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;/*** @Author tigerhhzz* @Date 2024 05 01 13 04**/
@Repository
public interface SysRoleMapper extends BaseMapper<SysRole> {}

com.baomidou.mybatisplus.core.mapper.BaseMapper这是Mybatis-Plus提供的默认Mapper接口。

package com.baomidou.mybatisplus.core.mapper;import com.baomidou.mybatisplus.core.conditions.Wrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import java.io.Serializable;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import org.apache.ibatis.annotations.Param;public interface BaseMapper<T> extends Mapper<T> {int insert(T entity);int deleteById(Serializable id);int deleteByMap(@Param("cm") Map<String, Object> columnMap);int delete(@Param("ew") Wrapper<T> queryWrapper);int deleteBatchIds(@Param("coll") Collection<? extends Serializable> idList);int updateById(@Param("et") T entity);int update(@Param("et") T entity, @Param("ew") Wrapper<T> updateWrapper);T selectById(Serializable id);List<T> selectBatchIds(@Param("coll") Collection<? extends Serializable> idList);List<T> selectByMap(@Param("cm") Map<String, Object> columnMap);T selectOne(@Param("ew") Wrapper<T> queryWrapper);Integer selectCount(@Param("ew") Wrapper<T> queryWrapper);List<T> selectList(@Param("ew") Wrapper<T> queryWrapper);List<Map<String, Object>> selectMaps(@Param("ew") Wrapper<T> queryWrapper);List<Object> selectObjs(@Param("ew") Wrapper<T> queryWrapper);<E extends IPage<T>> E selectPage(E page, @Param("ew") Wrapper<T> queryWrapper);<E extends IPage<Map<String, Object>>> E selectMapsPage(E page, @Param("ew") Wrapper<T> queryWrapper);
}

5、测试Mapper接口

package com.atsurvey.auth;import com.atsurvey.auth.mapper.SysRoleMapper;
import com.atsurvey.model.system.SysRole;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;import java.util.Arrays;
import java.util.List;/*** @Author tigerhhzz* @Date 2024 05 01 16 50**/
@SpringBootTest
public class TestMpDemo1 {//注入@Autowiredprivate SysRoleMapper sysRoleMapper;//查询所有记录@Testpublic void getAll() {List<SysRole> list = sysRoleMapper.selectList(null);System.out.println(list);}//添加操作@Testpublic void add() {SysRole sysRole = new SysRole();sysRole.setRoleName("角色管理员2");sysRole.setRoleCode("role2");sysRole.setDescription("角色管理员2");int rows = sysRoleMapper.insert(sysRole);System.out.println(rows);System.out.println(sysRole.getId());}//修改操作@Testpublic void update() {//根据id查询SysRole role = sysRoleMapper.selectById(10);//设置修改值role.setRoleName("atsurvey角色管理员");//调用方法实现最终修改int rows = sysRoleMapper.updateById(role);System.out.println(rows);}//删除操作@Testpublic void deleteId() {int rows = sysRoleMapper.deleteById(10);}//批量删除@Testpublic void testDeleteBatchIds() {int result = sysRoleMapper.deleteBatchIds(Arrays.asList(1, 2));System.out.println(result);}//条件查询@Testpublic void testQuery1() {//创建QueryWrapper对象，调用方法封装条件QueryWrapper<SysRole> wrapper = new QueryWrapper<>();wrapper.eq("role_name","总经理");//调用mp方法实现查询操作List<SysRole> list = sysRoleMapper.selectList(wrapper);System.out.println(list);}@Testpublic void testQuery2() {//LambdaQueryWrapper，调用方法封装条件LambdaQueryWrapper<SysRole> wrapper = new LambdaQueryWrapper<>();wrapper.eq(SysRole::getRoleName,"总经理");//调用mp方法实现查询操作List<SysRole> list = sysRoleMapper.selectList(wrapper);System.out.println(list);}
}

注意：

IDEA在sysRoleMapper处报错，因为找不到注入的对象，因为类是动态创建的，但是程序可以正确的执行。

为了避免报错，可以在 mapper 层 的接口上添加 @Repository 或直接使用 @Resource 代替 @Autowired。

控制台输出：

通过以上几个简单的步骤，我们就实现了 User 表的 CRUD 功能，甚至连 XML 文件都不用编写！

6、CRUD测试

6.1、insert添加

6.1.1、示例

    //添加操作@Testpublic void add() {SysRole sysRole = new SysRole();sysRole.setRoleName("角色管理员2");sysRole.setRoleCode("role2");sysRole.setDescription("角色管理员2");int rows = sysRoleMapper.insert(sysRole);System.out.println(rows);System.out.println(sysRole.getId());}

6.1.2、主键策略

1、ID_WORKER

MyBatis-Plus默认的主键策略是：ID_WORKER 全局唯一ID

2、自增策略

• 要想主键自增需要配置如下主键策略

• • 需要在创建数据表的时候设置主键自增
  • 实体字段中配置 @TableId(type = IdType.AUTO)

@TableId(type = IdType.AUTO)
private Long id;

其它主键策略：分析 IdType 源码可知

public enum IdType {/*** 数据库ID自增*/AUTO(0),/*** 该类型为未设置主键类型*/NONE(1),/*** 用户输入ID* 该类型可以通过自己注册自动填充插件进行填充*/    INPUT(2),/*** 全局唯一ID*/    ASSIGN_ID(3),/*** 全局唯一ID (UUID)*/ASSIGN_UUID(4),/** @deprecated */@DeprecatedID_WORKER(3),/** @deprecated */@DeprecatedID_WORKER_STR(3),/** @deprecated */@DeprecatedUUID(4);private final int key;private IdType(int key) {this.key = key;}public int getKey() {return this.key;}
}

6.2、更新

@Test
public void testUpdateById(){SysRole sysRole = new SysRole();sysRole.setId(1L);sysRole.setRoleName("角色管理员1");int result = sysRoleMapper.updateById(sysRole);System.out.println(result);}

6.3、删除

6.3.1、根据id删除

/*** application-dev.yml 加入配置* 此为默认值，如果你的默认值和mp默认的一样，则不需要该配置* mybatis-plus:*   global-config:*     db-config:*       logic-delete-value: 1*       logic-not-delete-value: 0*/
@Test
public void testDeleteById(){int result = sysRoleMapper.deleteById(2L);System.out.println(result);
}

6.3.2、批量删除

@Test
public void testDeleteBatchIds() {int result = sysRoleMapper.deleteBatchIds(Arrays.asList(1, 1));System.out.println(result);
}

6.4、MyBatis-Plus条件构造器

Wrapper ： 条件构造抽象类，最顶端父类

AbstractWrapper ： 用于查询条件封装，生成 sql 的 where 条件

​ QueryWrapper ： Entity 对象封装操作类，不是用lambda语法

​ UpdateWrapper ： Update 条件封装，用于Entity对象更新操作

AbstractLambdaWrapper ： Lambda 语法使用 Wrapper统一处理解析 lambda 获取 column。

​ LambdaQueryWrapper ：看名称也能明白就是用于Lambda语法使用的查询Wrapper

​ LambdaUpdateWrapper ： Lambda 更新封装Wrapper

注意：以下条件构造器的方法入参中的 column 均表示数据库字段

@Test
public void testSelect1() {QueryWrapper<SysRole> queryWrapper = new QueryWrapper<>();queryWrapper.eq("role_code", "role");List<SysRole> users = sysRoleMapper.selectList(queryWrapper);System.out.println(users);
}@Test
public void testSelect2() {LambdaQueryWrapper<SysRole> queryWrapper = new LambdaQueryWrapper<>();queryWrapper.eq(SysRole::getRoleCode, "role");List<SysRole> users = sysRoleMapper.selectList(queryWrapper);System.out.println(users);
}

其他条件构造可自行测试

6、MyBatis-Plus封装service层

6.1、添加service接口

package com.atsurvey.auth.service;import com.atsurvey.model.system.SysRole;
import com.baomidou.mybatisplus.extension.service.IService;
import org.springframework.stereotype.Service;import java.util.Map;@Service
public interface SysRoleService extends IService<SysRole> {}

com.baomidou.mybatisplus.extension.service.IService这是Mybatis-Plus提供的默认Service接口。

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//package com.baomidou.mybatisplus.extension.service;import com.baomidou.mybatisplus.core.conditions.Wrapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.core.toolkit.Assert;
import com.baomidou.mybatisplus.core.toolkit.CollectionUtils;
import com.baomidou.mybatisplus.core.toolkit.Wrappers;
import com.baomidou.mybatisplus.extension.conditions.query.LambdaQueryChainWrapper;
import com.baomidou.mybatisplus.extension.conditions.query.QueryChainWrapper;
import com.baomidou.mybatisplus.extension.conditions.update.LambdaUpdateChainWrapper;
import com.baomidou.mybatisplus.extension.conditions.update.UpdateChainWrapper;
import com.baomidou.mybatisplus.extension.kotlin.KtQueryChainWrapper;
import com.baomidou.mybatisplus.extension.kotlin.KtUpdateChainWrapper;
import com.baomidou.mybatisplus.extension.toolkit.ChainWrappers;
import com.baomidou.mybatisplus.extension.toolkit.SqlHelper;
import java.io.Serializable;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.function.Function;
import java.util.stream.Collectors;
import org.springframework.transaction.annotation.Transactional;public interface IService<T> {int DEFAULT_BATCH_SIZE = 1000;default boolean save(T entity) {return SqlHelper.retBool(this.getBaseMapper().insert(entity));}@Transactional(rollbackFor = {Exception.class})default boolean saveBatch(Collection<T> entityList) {return this.saveBatch(entityList, 1000);}boolean saveBatch(Collection<T> entityList, int batchSize);@Transactional(rollbackFor = {Exception.class})default boolean saveOrUpdateBatch(Collection<T> entityList) {return this.saveOrUpdateBatch(entityList, 1000);}boolean saveOrUpdateBatch(Collection<T> entityList, int batchSize);default boolean removeById(Serializable id) {return SqlHelper.retBool(this.getBaseMapper().deleteById(id));}default boolean removeByMap(Map<String, Object> columnMap) {Assert.notEmpty(columnMap, "error: columnMap must not be empty", new Object[0]);return SqlHelper.retBool(this.getBaseMapper().deleteByMap(columnMap));}default boolean remove(Wrapper<T> queryWrapper) {return SqlHelper.retBool(this.getBaseMapper().delete(queryWrapper));}default boolean removeByIds(Collection<? extends Serializable> idList) {return CollectionUtils.isEmpty(idList) ? false : SqlHelper.retBool(this.getBaseMapper().deleteBatchIds(idList));}default boolean updateById(T entity) {return SqlHelper.retBool(this.getBaseMapper().updateById(entity));}default boolean update(Wrapper<T> updateWrapper) {return this.update((Object)null, updateWrapper);}default boolean update(T entity, Wrapper<T> updateWrapper) {return SqlHelper.retBool(this.getBaseMapper().update(entity, updateWrapper));}@Transactional(rollbackFor = {Exception.class})default boolean updateBatchById(Collection<T> entityList) {return this.updateBatchById(entityList, 1000);}boolean updateBatchById(Collection<T> entityList, int batchSize);boolean saveOrUpdate(T entity);default T getById(Serializable id) {return this.getBaseMapper().selectById(id);}default List<T> listByIds(Collection<? extends Serializable> idList) {return this.getBaseMapper().selectBatchIds(idList);}default List<T> listByMap(Map<String, Object> columnMap) {return this.getBaseMapper().selectByMap(columnMap);}default T getOne(Wrapper<T> queryWrapper) {return this.getOne(queryWrapper, true);}T getOne(Wrapper<T> queryWrapper, boolean throwEx);Map<String, Object> getMap(Wrapper<T> queryWrapper);<V> V getObj(Wrapper<T> queryWrapper, Function<? super Object, V> mapper);default int count() {return this.count(Wrappers.emptyWrapper());}default int count(Wrapper<T> queryWrapper) {return SqlHelper.retCount(this.getBaseMapper().selectCount(queryWrapper));}default List<T> list(Wrapper<T> queryWrapper) {return this.getBaseMapper().selectList(queryWrapper);}default List<T> list() {return this.list(Wrappers.emptyWrapper());}default <E extends IPage<T>> E page(E page, Wrapper<T> queryWrapper) {return this.getBaseMapper().selectPage(page, queryWrapper);}default <E extends IPage<T>> E page(E page) {return this.page(page, Wrappers.emptyWrapper());}default List<Map<String, Object>> listMaps(Wrapper<T> queryWrapper) {return this.getBaseMapper().selectMaps(queryWrapper);}default List<Map<String, Object>> listMaps() {return this.listMaps(Wrappers.emptyWrapper());}default List<Object> listObjs() {return this.listObjs(Function.identity());}default <V> List<V> listObjs(Function<? super Object, V> mapper) {return this.listObjs(Wrappers.emptyWrapper(), mapper);}default List<Object> listObjs(Wrapper<T> queryWrapper) {return this.listObjs(queryWrapper, Function.identity());}default <V> List<V> listObjs(Wrapper<T> queryWrapper, Function<? super Object, V> mapper) {return (List)this.getBaseMapper().selectObjs(queryWrapper).stream().filter(Objects::nonNull).map(mapper).collect(Collectors.toList());}default <E extends IPage<Map<String, Object>>> E pageMaps(E page, Wrapper<T> queryWrapper) {return this.getBaseMapper().selectMapsPage(page, queryWrapper);}default <E extends IPage<Map<String, Object>>> E pageMaps(E page) {return this.pageMaps(page, Wrappers.emptyWrapper());}BaseMapper<T> getBaseMapper();Class<T> getEntityClass();default QueryChainWrapper<T> query() {return ChainWrappers.queryChain(this.getBaseMapper());}default LambdaQueryChainWrapper<T> lambdaQuery() {return ChainWrappers.lambdaQueryChain(this.getBaseMapper());}default KtQueryChainWrapper<T> ktQuery() {return ChainWrappers.ktQueryChain(this.getBaseMapper(), this.getEntityClass());}default KtUpdateChainWrapper<T> ktUpdate() {return ChainWrappers.ktUpdateChain(this.getBaseMapper(), this.getEntityClass());}default UpdateChainWrapper<T> update() {return ChainWrappers.updateChain(this.getBaseMapper());}default LambdaUpdateChainWrapper<T> lambdaUpdate() {return ChainWrappers.lambdaUpdateChain(this.getBaseMapper());}default boolean saveOrUpdate(T entity, Wrapper<T> updateWrapper) {return this.update(entity, updateWrapper) || this.saveOrUpdate(entity);}
}

6.2、添加service接口实现

package com.atsurvey.auth.service.impl;import com.atsurvey.auth.mapper.SysRoleMapper;
import com.atsurvey.auth.mapper.SysUserRoleMapper;
import com.atsurvey.auth.service.SysRoleService;
import com.atsurvey.model.system.SysRole;
import com.atsurvey.model.system.SysUserRole;
import com.atsurvey.vo.system.AssignRoleVo;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.StringUtils;import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;@Service
public class SysRoleServiceImpl extends ServiceImpl<SysRoleMapper, SysRole> implements SysRoleService {@Autowiredprivate SysUserRoleMapper sysUserRoleMapper;}

com.baomidou.mybatisplus.extension.service.impl.ServiceImpl这是Mybatis-Plus提供的默认Service接口实现。

6.3、测试Service接口

package com.atsurvey;import com.atsurvey.model.system.SysRole;
import com.atsurvey.system.mapper.SysRoleMapper;
import com.atsurvey.system.service.SysRoleService;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;import java.util.List;@RunWith(SpringRunner.class)
@SpringBootTest
public class SysRoleServiceTest {@Autowiredprivate SysRoleService sysRoleService;@Testpublic void testSelectList() {System.out.println(("----- selectAll method test ------"));//UserMapper 中的 selectList() 方法的参数为 MP 内置的条件封装器 Wrapper//所以不填写就是无任何条件List<SysRole> users = sysRoleService.list();users.forEach(System.out::println);}@Testpublic void testInsert(){SysRole sysRole = new SysRole();sysRole.setRoleName("角色管理员");sysRole.setRoleCode("role");sysRole.setDescription("角色管理员");boolean result = sysRoleService.save(sysRole);System.out.println(result); //影响的行数System.out.println(sysRole); //id自动回填}@Testpublic void testUpdateById(){SysRole sysRole = new SysRole();sysRole.setId(1L);sysRole.setRoleName("角色管理员1");boolean result = sysRoleService.updateById(sysRole);System.out.println(result);}@Testpublic void testDeleteById(){boolean result = sysRoleService.removeById(2L);System.out.println(result);}@Testpublic void testSelect1() {QueryWrapper<SysRole> queryWrapper = new QueryWrapper<>();queryWrapper.ge("role_code", "role");List<SysRole> users = sysRoleService.list(queryWrapper);System.out.println(users);}@Testpublic void testSelect2() {LambdaQueryWrapper<SysRole> queryWrapper = new LambdaQueryWrapper<>();queryWrapper.ge(SysRole::getRoleCode, "role");List<SysRole> users = sysRoleService.list(queryWrapper);System.out.println(users);}
}

三、角色管理

1、测试controller层

1.1、添加Controller

package com.atsurvey.auth.controller;import com.atsurvey.auth.service.SysRoleService;
import com.atsurvey.common.handler.ClfwzxException;
import com.atsurvey.common.result.Result;
import com.atsurvey.model.system.SysRole;
import com.atsurvey.vo.system.AssignRoleVo;
import com.atsurvey.vo.system.SysRoleQueryVo;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import io.swagger.annotations.ApiParam;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.access.prepost.PreAuthorize;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.*;import java.util.List;
import java.util.Map;@Api(tags = "角色管理")
@RestController
@RequestMapping("/admin/system/sysRole")
public class SysRoleController {@Autowiredprivate SysRoleService sysRoleService;@ApiOperation(value = "获取全部角色列表")@GetMapping("findAll")public Result<List<SysRole>> findAll() {List<SysRole> roleList = sysRoleService.list();try{int i = 10/0;}catch (Exception e){//抛出异常throw new ClfwzxException(20001,"执行了自定义异常处理...");}return Result.ok(roleList);}
}

1.2、测试Controller接口

http://localhost:8800/admin/system/sysRole/findAll

2、定义统一返回结果对象

项目中我们会将响应封装成json返回，一般我们会将所有接口的数据格式统一， 使前端(iOS Android, Web)对数据的操作更一致、轻松。

一般情况下，统一返回数据格式没有固定的格式，只要能描述清楚返回的数据状态以及要返回的具体数据就可以。但是一般会包含状态码、返回消息、数据这几部分内容

例如，我们的系统要求返回的基本数据格式如下：

列表：

{"code": 200,"message": "成功","data": [{"id": 2,"roleName": "系统管理员"}],"ok": true
}

分页：

{"code": 200,"message": "成功","data": {"records": [{"id": 2,"roleName": "系统管理员"},{"id": 3,"name": "普通管理员"}],"total": 10,"size": 3,"current": 1,"orders": [],"hitCount": false,"searchCount": true,"pages": 2},"ok": true
}

没有返回数据：

{"code": 200,"message": "成功","data": null,"ok": true
}

失败：

{"code": 201,"message": "失败","data": null,"ok": false
}

2.1、定义统一返回结果对象

操作模块：common-util

后续其他模块也会用到，故抽取到common-util模块

package com.atsurvey.common.result;import lombok.Data;/*** 全局统一返回结果类**/
@Data
public class Result<T> {//返回码private Integer code;//返回消息private String message;//返回数据private T data;public Result(){}// 返回数据protected static <T> Result<T> build(T data) {Result<T> result = new Result<T>();if (data != null)result.setData(data);return result;}public static <T> Result<T> build(T body, Integer code, String message) {Result<T> result = build(body);result.setCode(code);result.setMessage(message);return result;}public static <T> Result<T> build(T body, ResultCodeEnum resultCodeEnum) {Result<T> result = build(body);result.setCode(resultCodeEnum.getCode());result.setMessage(resultCodeEnum.getMessage());return result;}public static<T> Result<T> ok(){return Result.ok(null);}/*** 操作成功* @param data  baseCategory1List* @param <T>* @return*/public static<T> Result<T> ok(T data){Result<T> result = build(data);return build(data, ResultCodeEnum.SUCCESS);}public static<T> Result<T> fail(){return Result.fail(null);}/*** 操作失败* @param data* @param <T>* @return*/public static<T> Result<T> fail(T data){Result<T> result = build(data);return build(data, ResultCodeEnum.FAIL);}public Result<T> message(String msg){this.setMessage(msg);return this;}public Result<T> code(Integer code){this.setCode(code);return this;}
}

统一返回结果状态信息类

下面的状态后续都会用到，所以直接引入了

package com.atsurvey.common.result;import lombok.Getter;/*** 统一返回结果状态信息类**/
@Getter
public enum ResultCodeEnum {SUCCESS(200,"成功"),FAIL(201, "失败"),SERVICE_ERROR(2012, "服务异常"),DATA_ERROR(204, "数据异常"),LOGIN_AUTH(208, "未登陆"),PERMISSION(209, "没有权限");private Integer code;private String message;private ResultCodeEnum(Integer code, String message) {this.code = code;this.message = message;}
}

2.2、改造controller方法

@GetMapping("findAll")
public Result<List<SysRole>> findAll() {List<SysRole> roleList = sysRoleService.list();return Result.ok(roleList);
}

2.3、测试接口

http://localhost:8800/admin/system/sysRole/findAll

3、knife4j

文档地址：https://doc.xiaominfo.com/

knife4j是为Java MVC框架集成Swagger生成Api文档的增强解决方案。

3.1、Swagger介绍

前后端分离开发模式中，api文档是最好的沟通方式。

Swagger 是一个规范和完整的框架，用于生成、描述、调用和可视化 RESTful 风格的 Web 服务。

1、及时性 (接口变更后，能够及时准确地通知相关前后端开发人员)

2、规范性 (并且保证接口的规范性，如接口的地址，请求方式，参数及响应格式和错误信息)

3、一致性 (接口信息一致，不会出现因开发人员拿到的文档版本不一致，而出现分歧)

4、可测性 (直接在接口文档上进行测试，以方便理解业务)

3.2、集成knife4j

knife4j属于service模块公共资源，因此我们集成到service-uitl模块

3.2.1 添加依赖

操作模块：service-uitl

<dependency><groupId>com.github.xiaoymin</groupId><artifactId>knife4j-spring-boot-starter</artifactId>
</dependency>

说明：guigu-auth-parent已加入版本管理

3.2.2 添加knife4j配置类

操作模块：service-uitl

package com.atsurvey.common.config.knife4j;import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.ApiInfoBuilder;
import springfox.documentation.builders.ParameterBuilder;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.builders.RequestHandlerSelectors;
import springfox.documentation.schema.ModelRef;
import springfox.documentation.service.ApiInfo;
import springfox.documentation.service.Contact;
import springfox.documentation.service.Parameter;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger2.annotations.EnableSwagger2WebMvc;import java.util.ArrayList;
import java.util.List;/*** knife4j配置信息*/
@Configuration
@EnableSwagger2WebMvc
public class Knife4jConfig {@Beanpublic Docket adminApiConfig(){List<Parameter> pars = new ArrayList<>();ParameterBuilder tokenPar = new ParameterBuilder();tokenPar.name("token").description("用户token").defaultValue("").modelRef(new ModelRef("string")).parameterType("header").required(false).build();pars.add(tokenPar.build());//添加head参数endDocket adminApi = new Docket(DocumentationType.SWAGGER_2).groupName("adminApi").apiInfo(adminApiInfo()).select()//只显示admin路径下的页面.apis(RequestHandlerSelectors.basePackage("com.atsurvey")).paths(PathSelectors.regex("/admin/.*")).build().globalOperationParameters(pars);return adminApi;}private ApiInfo adminApiInfo(){return new ApiInfoBuilder().title("后台管理系统-API文档").description("本文档描述了后台管理系统微服务接口定义").version("1.0").contact(new Contact("atsurvey", "http://atsurvey.com", "atsurvey@qq.com")).build();}}

3.2.3 Controller层添加注解

package com.atsurvey.system.controller;import com.atsurvey.system.service.SysRoleService;
import com.atsurvey.common.result.Result;
import com.atsurvey.model.system.SysRole;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import java.util.List;@Api(tags = "角色管理")
@RestController
@RequestMapping("/admin/system/sysRole")
public class SysRoleController {@Autowiredprivate SysRoleService sysRoleService;@ApiOperation(value = "获取全部角色列表")@GetMapping("findAll")public Result<List<SysRole>> findAll() {List<SysRole> roleList = sysRoleService.list();return Result.ok(roleList);}
}

3.2.4、测试

http://localhost:8800/doc.html

4、分页查询

4.1、配置分页插件

操作模块：service-uitl，service公共资源

说明：我们将@MapperScan(“com.atsurvey.auth.mapper”)提取到该配置类上面，统一管理，启动类就不需要了。

package com.atsurvey.common.config.mp;import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.autoconfigure.ConfigurationCustomizer;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;@Configuration
@MapperScan("com.atsurvey.auth.mapper")
public class MybatisPlusConfig {/*** 新的分页插件,一缓和二缓遵循mybatis的规则,需要设置 MybatisConfiguration#useDeprecatedExecutor = false 避免缓存出现问题(该属性会在旧插件移除后一同移除)*/@Beanpublic MybatisPlusInterceptor mybatisPlusInterceptor() {MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));return interceptor;}@Beanpublic ConfigurationCustomizer configurationCustomizer() {return configuration -> configuration.setUseDeprecatedExecutor(false);}
}

4.2、分页controller

//条件分页查询
//page 当前页  limit 每页显示记录数
//SysRoleQueryVo 条件对象
@ApiOperation("条件分页查询")
@GetMapping("{page}/{limit}")
public Result pageQueryRole(@PathVariable Long page,@PathVariable Long limit,SysRoleQueryVo sysRoleQueryVo) {//调用service的方法实现//1 创建Page对象，传递分页相关参数//page 当前页  limit 每页显示记录数Page<SysRole> pageParam = new Page<>(page,limit);//2 封装条件，判断条件是否为空，不为空进行封装LambdaQueryWrapper<SysRole> wrapper = new LambdaQueryWrapper<>();String roleName = sysRoleQueryVo.getRoleName();if(!StringUtils.isEmpty(roleName)) {//封装 like模糊查询wrapper.like(SysRole::getRoleName,roleName);}//3 调用方法实现IPage<SysRole> pageModel = sysRoleService.page(pageParam, wrapper);return Result.ok(pageModel);
}

5、其他controller方法

说明：通过knife4j测试接口

@ApiOperation(value = "获取")
@GetMapping("get/{id}")
public Result get(@PathVariable Long id) {SysRole role = sysRoleService.getById(id);return Result.ok(role);
}@ApiOperation(value = "新增角色")
@PostMapping("save")
public Result save(@RequestBody @Validated SysRole role) {sysRoleService.save(role);return Result.ok();
}@ApiOperation(value = "修改角色")
@PutMapping("update")
public Result updateById(@RequestBody SysRole role) {sysRoleService.updateById(role);return Result.ok();
}@ApiOperation(value = "删除角色")
@DeleteMapping("remove/{id}")
public Result remove(@PathVariable Long id) {sysRoleService.removeById(id);return Result.ok();
}@ApiOperation(value = "根据id列表删除")
@DeleteMapping("batchRemove")
public Result batchRemove(@RequestBody List<Long> idList) {sysRoleService.removeByIds(idList);return Result.ok();
}

配置日期时间格式

application-dev.yml添加以下内容

  jackson:date-format: yyyy-MM-dd HH:mm:sstime-zone: GMT+8

6、统一异常处理

6.1、制造异常

除以0

int a = 10/0;

我们想让异常结果也显示为统一的返回结果对象，并且统一处理系统的异常信息，那么需要统一异常处理。

6.2、全局异常处理

6.2.1、创建统一异常处理器

操作模块：service-util

package com.atsurvey.common.handler;import com.atsurvey.common.result.Result;
import org.springframework.web.bind.annotation.ControllerAdvice;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.ResponseBody;/*** 全局异常处理类**/
@ControllerAdvice
public class GlobalExceptionHandler {@ExceptionHandler(Exception.class)@ResponseBodypublic Result error(Exception e){e.printStackTrace();return Result.fail();}
}

6.2.1、测试

6.3、处理特定异常

6.3.1、添加异常处理方法

GlobalExceptionHandler.java中添加

@ExceptionHandler(ArithmeticException.class)
@ResponseBody
public Result error(ArithmeticException e){e.printStackTrace();return Result.fail().message("执行了特定异常处理");
}

6.3.2、测试

6.4、处理自定义异常

6.4.1、创建自定义异常类

package com.atsurvey.common.execption;import com.atguigu.common.result.ResultCodeEnum;
import lombok.Data;/*** 自定义全局异常类**/
@Data
public class ClfwzxException extends RuntimeException {private Integer code;private String message;/*** 通过状态码和错误消息创建异常对象* @param code* @param message*/public ClfwzxException(Integer code, String message) {super(message);this.code = code;this.message = message;}/*** 接收枚举类型对象* @param resultCodeEnum*/public ClfwzxException(ResultCodeEnum resultCodeEnum) {super(resultCodeEnum.getMessage());this.code = resultCodeEnum.getCode();this.message = resultCodeEnum.getMessage();}@Overridepublic String toString() {return "GuliException{" +"code=" + code +", message=" + this.getMessage() +'}';}
}

6.4.2、业务中需要位置抛出

try {int a = 10/0;
}catch(Exception e) {throw new ClfwzxException(20001,"出现自定义异常");
}

6.4.3、添加异常处理方法

GlobalExceptionHandler.java中添加

@ExceptionHandler(ClfwzxException.class)
@ResponseBody
public Result error(ClfwzxExceptione){e.printStackTrace();return Result.fail().message(e.getMsg()).code(e.getCode());
}