实战：在SpringBoot中使用MongoDB

前言

MongoDB基础教程： MongoDB教程合集    MongoDB教程（易百教程）

spring-data-mongodb注解：   Spring中MongoDB注解概念及使用

一、pom.xml依赖配置

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.scb</groupId>
    <artifactId>mongo-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>mongo-demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.39</version>
        </dependency>
        <dependency>
            <groupId>ch.qos.logback</groupId>
            <artifactId>logback-classic</artifactId>
            <version>1.1.11</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

二、在application.yml配置文件中配置如下信息

spring:
  data:
    mongodb:
      host: localhost
      port: 27017
       #MongoDB的数据库名
      database: springboot

三、创建实体类

package com.scb.mongodemo.entity;

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;

import java.io.Serializable;

@Data
@Document
public class Role implements Serializable {
    private static final long serialVersionUID = -7111768727538023614L;

    @Id
    private Long id;

    @Field("role_name")
    private String roleName;

    @Field("note")
    private String note;
}

package com.scb.mongodemo.entity;

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;

import java.io.Serializable;
import java.util.List;

@Data
@Document
public class User implements Serializable {
    private static final long serialVersionUID = -2222439945682451664L;

    @Id
    private Long id;

    @Field("user_name")
    private String userName;

    @Field("note")
    private String note;

    @Field("roles")
    private List<Role> roles;
}

四、使用MongoRepository实现DAO层操作

package com.scb.mongodemo.repository;

import com.scb.mongodemo.entity.User;
import org.springframework.data.mongodb.repository.MongoRepository;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository
public interface UserRepository extends MongoRepository<User,Long> {
    List<User> findByUserNameLike(String userName);
}

注：MongoDB是一个十分接近于关系数据库的NoSQL数据库，因此，它也允许我们使用JPA编程。

有关JPA编程学习的文章：Spring Data JPA学习导引

五、控制层

package com.scb.mongodemo.controller;

import com.scb.mongodemo.entity.Role;
import com.scb.mongodemo.entity.User;
import com.scb.mongodemo.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.*;

@RestController
@RequestMapping("/user")
public class UserController {
    @Autowired
    UserRepository userRepository;

    @GetMapping("/{userName}")
    public List<User> findByUserName(@PathVariable String userName) {
        return userRepository.findByUserNameLike(userName);
    }

    @PostMapping("/initUsers")
    public List<User> initUsers(){
        List<User> saveUsers=new ArrayList<>();
        for (int i=1;i<=10;i++){
            User user=new User();
            user.setId((long)i);
            user.setUserName("user_name_"+i);
            user.setNote("user_note_"+i);

            Role role=new Role();
            role.setId((long)i);
            role.setRoleName("role_name_"+i);
            role.setNote("role_note_"+i);
            List<Role> roles=new ArrayList<>();
            roles.add(role);
            user.setRoles(roles);

            saveUsers.add(userRepository.save(user));
        }
        return saveUsers;
    }
}

这里因为是测试使用的缘故，就不实现service层了，直接使用UserRepository进行操作。

六、运行测试

注：在运行项目时候，要记得打开MongoDB的服务端。

使用Postman测试工具，以post方式访问 localhost:8080/user/initUsers

可以看到数据已经插入成功了。在使用Robo 3T客户端软件查看数据（当然也使用命令行），发现多了个"_class"属性，这是用来反序列化时候使用的。