MongoDB学习(四) --- MongoDB 整合Spring Data

1、环境搭建

• 步骤一：修改pom文件，更新依赖

  
  	org.springframework.boot
  	spring-boot-starter-data-mongodb
  
  
  	org.projectlombok
  	lombok
  
  

• 步骤二：修改yml文件，配置 mongo连接字符串

  spring:
    data:
      mongodb:
        uri:  mongodb://root:1234@localhost:27017/admin
  

• 步骤三：编写 JavaBean，配置文档对应集合

  package com.tqyl.domain;
  
  import lombok.Data;
  import org.springframework.data.annotation.Id;
  import org.springframework.data.mongodb.core.mapping.Document;
  import org.springframework.data.mongodb.core.mapping.Field;
  
  
  @Data
  @Document(collection = "teacher")
  public class Teacher {
      @Id
      private String teacherId;
      @Field("username")
      private String username;
      private String password;
      private Integer age;
  
      public Teacher() {
      }
  
      public Teacher(String teacherId, String username, String password, Integer age) {
          this.teacherId = teacherId;
          this.username = username;
          this.password = password;
          this.age = age;
      }
  }
  
  

• 步骤四：编写 dao，继承MongoRepository

  package com.tqyl.dao;
  
  import com.tqyl.domain.Teacher;
  import org.springframework.data.mongodb.repository.MongoRepository;
  
  import java.util.List;
  
  
  public interface TeacherDao extends MongoRepository {
  
      public List findByUsername(String username);
  }
  
  

• 步骤五：编写启动类，使用@ComponentScan扫描 dao

  package com.tqyl;
  
  import org.springframework.boot.SpringApplication;
  import org.springframework.boot.autoconfigure.SpringBootApplication;
  import org.springframework.context.annotation.ComponentScan;
  
  
  @SpringBootApplication
  @ComponentScan(basePackages = "com.tqyl.dao")
  public class TestApplication {
      public static void main(String[] args) {
          SpringApplication.run(TestApplication.class,args);
      }
  }
  
  

• 步骤六：编写测试类，获得 dao 实现类

  @RunWith(SpringRunner.class)
  @SpringBootTest(classes = TestApplication.class)
  public class TestRepository {
      @Resource
      private TeacherDao teacherDao;
  }
  

2、基础操作

2.1、查询所有

   @Test
    public void testFindAll(){
        //查询
        List list = teacherDao.findAll();
        System.out.println(list);
    }

2.2、排序查询

   @Test
    public void testDemo01(){
        //排序
        //List list = teacherRepository.findAll(Sort.by("password"));
        List list = teacherDao.findAll(Sort.by(Sort.Order.desc("password")));

        for (Teacher teacher : list) {
            System.out.println(teacher);
        }
    }

2.3、分页

• 分页基本操作

    @Test
    public void testDemo02(){
        //分页
        int page = 0;   //从0开始
        int size = 2;
        Page teacherPage = teacherDao.findAll(PageRequest.of(page, size));

        //处理分页数据
        //1 获得分页内容
        List list = teacherPage.getContent();
        //2 获得总记录数
        long total = teacherPage.getTotalElements();

        System.out.println("总条数：" + total);
        for (Teacher teacher : list) {
            System.out.println(teacher);
        }
    }

• 分页 jdk8 ForEach

    @Test
    public void testDemo03() {
        //分页
        int page = 0;   //从0开始
        int size = 2;
        Page teacherPage = teacherDao.findAll(PageRequest.of(page, size));

        //遍历数据
        // JDK8提供forEach，使用箭头函数进行遍历
        teacherPage.forEach(teacher -> System.out.println(teacher) );

        // 打印简化版
        teacherPage.forEach(System.out::println);
    }

2.5、添加

    @Test
    public void testDemo04(){
        //准备数据
        Teacher teacher = new Teacher();
        teacher.setUsername("王五");
        teacher.setPassword("666777");
        teacher.setAge(30);

        //插入数据
        teacherDao.insert( teacher );
    }

2.6、通过ID查询

    @Test
    public void testDemo05(){
        //通过id查询
        Optional optional = teacherDao.findById("5ee83ccf9d1c6904d8768ca8");
        //Optional 用于统一规范空指针异常处理
        if(optional.isPresent()){  // teacher != null
            Teacher teacher = optional.get();
            System.out.println(teacher);
        } else {
            System.out.println("没有数据");
        }
    }

2.7、更新

• 更新采用save方法
  • 如果数据存在，将发生更新操作
  • 如果数据不存在，将发生添加操作

    @Test
    public void testDemo06(){
        //更新操作
        //1 查询
        Optional optional = teacherDao.findById("5ee83ccf9d1c6904d8768ca8");

        if(optional.isPresent()) {
            //2 修改数据
            Teacher teacher = optional.get();
            teacher.setUsername("王武");
            //3 更新
            teacherDao.save(teacher);
        }
    }

2.8、删除

• deleteById() ：通过id删除
• deleteAll() ：删除所有

    @Test
    public void testDemo07(){
        //删除
        teacherDao.deleteById("5ee83ccf9d1c6904d8768ca8");
    }

2.9、自定义dao

• 在dao中，可以通过约定进行条件查询
  • 前缀：findBy
  • 查询条件：字段名
  • 关键字：And、Or、Like 等
• TeacherRepository

 public List findByUsername(String username);

    @Test
    public void testDemo08(){
        //自定义查询
        List list = teacherRepository.findByUsername("tom");
        System.out.println(list);

    }