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项目环境：

开发环境：IntelliJ IDEA 2019.3.1 ，JDK1.8 ，MySQL: 5.6.47

采用远程数据库连接：使用ailiyun ESC CentOS 7.0

项目技术：

学会使用mybatis-generator自动部署代码

学会使用tk.mybatis插件进行数据库的操作

学会实现父子表管子查询

项目资源连接：

项目说明

 本项目采用mybatis-generator的自动生成插件和Tk插件结合，实现对父子表的联合查询，使返回结果包括父表信息和它的子表每个子数据信息。

项目准备

创建数据库schooldb

 使用Navicat创建数据库schooldb，并运行下面的sql文件

SET NAMES utf8mb4;SET FOREIGN_KEY_CHECKS = 0;-- ------------------------------ Table structure for tbl_student-- ----------------------------DROP TABLE IF EXISTS `tbl_student`;CREATE TABLE `tbl_student`  (  `id` bigint(20) NOT NULL AUTO_INCREMENT,  `teacher_id` bigint(20) NULL DEFAULT NULL,  `name` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NULL DEFAULT NULL COMMENT '学生姓名',  `age` int(11) NULL DEFAULT NULL COMMENT '年龄',  PRIMARY KEY (`id`) USING BTREE) ENGINE = InnoDB AUTO_INCREMENT = 8 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_bin ROW_FORMAT = Compact;-- ------------------------------ Records of tbl_student-- ----------------------------INSERT INTO `tbl_student` VALUES (1, 1, '小明', 15);INSERT INTO `tbl_student` VALUES (2, 1, '小李', 15);INSERT INTO `tbl_student` VALUES (3, 1, '小红', 14);INSERT INTO `tbl_student` VALUES (4, 2, '小李', 14);INSERT INTO `tbl_student` VALUES (5, 2, '王二', 15);INSERT INTO `tbl_student` VALUES (6, 2, '张三', 13);-- ------------------------------ Table structure for tbl_teacher-- ----------------------------DROP TABLE IF EXISTS `tbl_teacher`;CREATE TABLE `tbl_teacher`  (  `id` bigint(20) NOT NULL AUTO_INCREMENT,  `name` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NULL DEFAULT NULL COMMENT '老师姓名',  `age` int(11) NULL DEFAULT NULL COMMENT '老师年龄',  `phone` int(11) NULL DEFAULT NULL COMMENT '手机号',  PRIMARY KEY (`id`) USING BTREE) ENGINE = InnoDB AUTO_INCREMENT = 3 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_bin ROW_FORMAT = Compact;-- ------------------------------ Records of tbl_teacher-- ----------------------------INSERT INTO `tbl_teacher` VALUES (1, '王老师', 45, 1596369856);INSERT INTO `tbl_teacher` VALUES (2, '李老师', 32, 1358948956);SET FOREIGN_KEY_CHECKS = 1;

项目结构

一、依赖与配置

依赖

           
                
     
      tk.mybatis
                 
     
      mapper-spring-boot-starter
                 
     
      2.0.4
             
            
                
     
      org.springframework.boot
                 
     
      spring-boot-starter-web
             
            
                
     
      org.mybatis.spring.boot
                 
     
      mybatis-spring-boot-starter
                 
     
      2.1.1
             
            
            
                
     
      com.alibaba
                 
     
      druid-spring-boot-starter
                 
     
      1.1.10
             
            
                
     
      mysql
                 
     
      mysql-connector-java
                 
     
      runtime
                 
                 
     
      5.1.6
             
            
                
     
      org.springframework.boot
                 
     
      spring-boot-starter-test
                 
     
      test
                 
                     
                          
       
        org.junit.vintage
                           
       
        junit-vintage-engine
                       
                  
             
        
       
           
                
                     
      
       org.springframework.boot
                      
      
       spring-boot-maven-plugin
                  
                 
                     
      
       org.mybatis.generator
                      
      
       mybatis-generator-maven-plugin
                      
      
       1.3.7
                      
                          
                               
        
         mysql
                                
        
         mysql-connector-java
                                
        
         runtime
                                
                                
        
         5.1.6
                            
                           
                           
                               
        
         tk.mybatis
                                
        
         mapper
                                
        
         4.1.5
                            
                       
                      
                          
                           
       
        ${basedir}/src/main/resources/mybatis-generator.xml
                           
       
        true
                           
       
        true
                       
                  
             
        
   

配置application.properties

#远程数据库连接spring.datasource.url=jdbc:mysql://121.40.83.80:3306/schooldb?characterEncoding=UTF-8&useSSL=false#数据库用户名spring.datasource.username=alvin#数据库密码spring.datasource.password=123456#数据源类型spring.datasource.type=com.alibaba.druid.pool.DruidDataSourcemybatis.mapper-locations=classpath:/mapper/*.xml

配置Tk<Mapper>

 在utils包下 创建TkMapper.java类

/** * 继承 * @param 
   
     */public interface TkMapper
    
      extends Mapper
     
      , MySqlMapper
      
        {
       //特别注意，该接口不能被扫描到，否则会出错}
      
     
    
   

配置mybatis-generator.xml

配置启动类

 这里需要在启动类加入一个注解@MapperScan(basePackages = "com.alvin.mybatis.mapper"),注意它的引包是import tk.mybatis.spring.annotation.MapperScan;

@SpringBootApplication//com.alvin.mybatis.mapper是我们扫描.mapper的地址@MapperScan(basePackages = "com.alvin.mybatis.mapper")public class MybatisApplication {
       public static void main(String[] args) {
           SpringApplication.run(MybatisApplication.class, args);    }}

配置data sources

二、自动生成

三、实现父子表查询

数据层

• StudentDto.java

public class StudentDto {
       private Long id;    private String name;    private Integer age;    private Long teacherId;    //省略setter/getter方法}

• TeacherDto.java

public class TeacherDto {
       private Long id;    private String name;    private Integer age;    private Integer phone;    private List
   
     dtoList;    //省略setter/getter方法}
   

控制层

• TestController.java

@Controllerpublic class TestController {
       @Autowired    TestService testService;        @ResponseBody    @GetMapping("/test")    public List
   
     search(            @RequestParam Long id    ){
           return testService.search(id);    }}
   

业务逻辑层

• TestService.java

@Servicepublic class TestService {
       @Autowired    StudentMapper studentMapper;    @Autowired    TeacherMapper teacherMapper;    public List
   
     search(Long id){
           List
    
       repList = new ArrayList<>();        TeacherDto teacherDto = new TeacherDto();        //查询该老师的所有信息        Teacher teacher = teacherMapper.selectByPrimaryKey(id);        BeanUtils.copyProperties(teacher,teacherDto);        repList.add(teacherDto);        //查询该老师的所有学生        Example example = new Example(Student.class);        example.createCriteria().andEqualTo("teacherId",id);        List
     
       students = studentMapper.selectByExample(example);        //查询每个学生的个人信息        List
      
        studentDtoList = new ArrayList<>();        for(Student student : students){
               StudentDto studentDto = new StudentDto();            BeanUtils.copyProperties(student,studentDto);            studentDtoList.add(studentDto);            teacherDto.setDtoList(studentDtoList);        }        return repList;    }}
      
     
    
   

也可以根据java8的特性使用stream代替for迭代

@Servicepublic class TestService {
       @Autowired    StudentMapper studentMapper;    @Autowired    TeacherMapper teacherMapper;    public List
   
     search(Long id){
           List
    
       repList = new ArrayList<>();        TeacherDto teacherDto = new TeacherDto();        //查询该老师的所有信息        Teacher teacher = teacherMapper.selectByPrimaryKey(id);        BeanUtils.copyProperties(teacher,teacherDto);        repList.add(teacherDto);        //查询该老师的所有学生        Example example = new Example(Student.class);        example.createCriteria().andEqualTo("teacherId",id);        List
     
       students = studentMapper.selectByExample(example);        //查询每个学生的个人信息        List
      
        list = students.stream().map(student -> {
               StudentDto studentDto = new StudentDto();            BeanUtils.copyProperties(student, studentDto);            return studentDto;        }).collect(Collectors.toList());        teacherDto.setDtoList(list);        return repList;}
      
     
    
   

四、Postman调用

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