介绍MongoDB与Spring Boo集成，并通过MongoRepository以及MongoTemplate来执行CRUD操作。

Spring Boot：2.3.0.RELEASE Spring Boot Data MongoDB：2.3.0.RELEASE MongoDB：4.2.6 MongoDB Driver：4.0.3

CRUD示例数据结构

Department： String id String name String description Array employees
Employee： String empId String name int age double salary
one to many relationships

安装MongoDB

docker-compose.yml ```yaml version: ‘3’ services: mongodb: container_name: “mongodb” image: “mongo:latest” environment: MONGO_INITDB_ROOT_USERNAME: root MONGO_INITDB_ROOT_PASSWORD: example ports:

- 27017:27017
logging:
  driver: "json-file"
  options:
    max-size: "50m"

安装并启动
```bash
/usr/local/bin/docker-compose -f /Users/chou/Documents/work/projects/demo/springboot-demo/springboot-mongodb/docker-compose.yml up -d mongodb

创建Spring Boot项目

略

添加Mongo依赖

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-mongodb</artifactId>
</dependency>

Spring application配置

application.properties

spring.data.mongodb.username=root
spring.data.mongodb.password=example
spring.data.mongodb.database=admin

测试能否正常启动

host：localhost port：27017 database：admin user：root password：example

项目结构

创建Domain Object

package com.example.mongodb.model;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.index.Indexed;
import org.springframework.data.mongodb.core.mapping.Document;
import java.util.List;
@Document("Department")
public class Department {
    @Id
    private String id;
    @Indexed(name = "deptName")
    private String name;
    private String description;
    @DBRef
    private List<Employee> employees;
    //...getter setter
}

package com.example.mongodb.model;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;
@Document("Employee")
public class Employee {
    @Id
    private String empId;
    private String name;
    private int age;
    private double salary;
    //...getter setter
}

@Document 标识了要持久化到mongodb的DO。
@Id 文档的唯一标识，在mongodb中是objectId。
@DbRef 关联另一个Document对象，存入的是文档的引用，如果不使用这个注解，存入的是内容。不过即使使用@DbRef，mongodb本身并不维护关联数据，也就是说需要手动将数据插入到被关联文档。

两种操作数据的方式

MongoRepository

package com.example.mongodb.repository;
import com.example.mongodb.model.Department;
import org.springframework.data.mongodb.repository.MongoRepository;
import org.springframework.data.mongodb.repository.Query;
import org.springframework.stereotype.Repository;
import java.util.List;
@Repository
public interface DepartmentRepository extends MongoRepository<Department,String> {
    @Query(value = "{'Employee.name': ?0}", fields = "{'employees' : 0}")
    Department findDepartmentByEmployeeName(String empName);
    List<Department> findDepartmentByName(String name);
}

MongoTemplate

package com.example.mongodb.repository;
import com.example.mongodb.model.Department;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.query.Criteria;
import org.springframework.data.mongodb.core.query.Query;
import org.springframework.data.mongodb.core.query.Update;
import org.springframework.stereotype.Repository;
import java.util.List;
@Repository
public class DeptRepository {
    @Autowired
    private MongoTemplate mongoTemplate;
    public List<Department> findAll() {
        return mongoTemplate.findAll(Department.class);
    }
    public List<Department> findDepartmentByName(String deptName){
        Query query = new Query();
        query.addCriteria(Criteria.where("name").is(deptName));
        return mongoTemplate.find(query, Department.class);
    }
    public Department save(Department department) {
        mongoTemplate.save(department);
        return department;
    }
    public Department update(Department department){
        Query query = new Query();
        query.addCriteria(Criteria.where("id").is(department.getId()));
        Update update = new Update();
        update.set("name", department.getName());
        update.set("description", department.getDescription());
        return mongoTemplate.findAndModify(query, update, Department.class);
    }
    public void deleteById(String deptId) {
        Query query = new Query();
        query.addCriteria(Criteria.where("id").is(deptId));
        mongoTemplate.remove(query, Department.class);
    }
}

创建Controller

package com.example.mongodb.controller;
import com.example.mongodb.model.Department;
import com.example.mongodb.model.Employee;
import com.example.mongodb.repository.DepartmentRepository;
import com.example.mongodb.repository.DeptRepository;
import com.example.mongodb.repository.EmpRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.Collections;
import java.util.List;
import java.util.Optional;
@RestController
public class DepartmentController {
    @Autowired
    DepartmentRepository departmentRepository;
    @Autowired
    DeptRepository deptRepository;
    @Autowired
    EmpRepository empRepository;
    @PostMapping("/v1/dept/s")
    public Department v1save(@RequestBody Department department) {
        List<Employee> employees = Optional.ofNullable(department.getEmployees()).orElse(Collections.emptyList());
        employees.forEach(employee -> empRepository.save(employee));
        return departmentRepository.save(department);
    }
    @GetMapping("/v1/dept/l")
    public List<Department> v1list(){
        return departmentRepository.findAll();
    }
    @PutMapping("/v1/dept/u/{deptId}")
    public Department v1update(@RequestBody Department department, @PathVariable String deptId) {
        department.setId(deptId);
        List<Employee> employees = Optional.ofNullable(department.getEmployees()).orElse(Collections.emptyList());
        employees.forEach(employee -> empRepository.save(employee));
        return departmentRepository.save(department);
    }
    @DeleteMapping("/v1/dept/d/{deptId}")
    public String v1delete(@PathVariable String deptId) {
        departmentRepository.deleteById(deptId);
        return deptId;
    }
    @GetMapping("/v1/dept/get/{deptName}")
    public List<Department> v1getByName(@PathVariable String deptName) {
        return departmentRepository.findDepartmentByName(deptName);
    }
    @GetMapping("/v1/dept/get/emp/{empName}")
    public Department v1getByEmpName(@PathVariable String empName) {
        return departmentRepository.findDepartmentByEmployeeName(empName);
    }
    @PostMapping("/v2/dept/s")
    public Department v2save(Department department) {
        List<Employee> employees = Optional.ofNullable(department.getEmployees()).orElse(Collections.emptyList());
        employees.forEach(employee -> empRepository.save(employee));
        return deptRepository.save(department);
    }
    @GetMapping("/v2/dept/l")
    public List<Department> v2list() {
        return deptRepository.findAll();
    }
    @PutMapping("/v2/dept/u")
    public Department v2update(Department department){
        List<Employee> employees = Optional.ofNullable(department.getEmployees()).orElse(Collections.emptyList());
        employees.forEach(employee -> empRepository.save(employee));
        return deptRepository.update(department);
    }
    @DeleteMapping("/v2/dept/d/{deptId}")
    public void v2delete(@PathVariable String deptId) {
        deptRepository.deleteById(deptId);
    }
    @GetMapping("/v2/dept/get/{deptName}")
    public List<Department> v2getByName(@PathVariable String deptName){
        return deptRepository.findDepartmentByName(deptName);
    }
}

v1的接口使用MongoRepository方式操作数据，v2的接口使用MonoTemplate方式操作数据。

测试

###新增
POST http://localhost:8080/v1/dept/s
Content-Type: application/json
{
  "id": "10010",
  "name": "中国联通",
  "description": "中国联通",
  "employees": [
    {
      "empId": "1",
      "name": "jack ma",
      "age": 78,
      "salary": 900000.0
    }
  ]
}
###更新
PUT http://localhost:8080/v1/dept/u/10010
Content-Type: application/json
{
  "id": "10010",
  "name": "中国联通",
  "description": "中国联通",
  "employees": [
    {
      "empId": "1",
      "name": "jack ma",
      "age": 78,
      "salary": 900000.0
    },
    {
      "empId": "2",
      "name": "pony ma",
      "age": 78,
      "salary": 900000.0
    }
  ]
}
###删除
DELETE http://localhost:8080/v1/dept/d/10010
###查询
GET http://localhost:8080/v1/dept/l

项目地址