Spring Boot——使用MongoDB

什么是MongoDB？MongoDB是文档型的NoSQL数据库，具有大数据量、高并发等优势，但缺点是不能建立实体关系，而且也没有事务管理机制。下面我们就看一下在Spring Boot基础下，如何使用MongoDB，编写数据访问。
引入Starer:

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

确认装有MongoDB以后，新建application.yml配置mongodb：

#配置mongodb参数
spring:
  data:
    mongodb:
      host: 172.30.0.218
      port: 27017
      database: mydb
#配置server参数
server:
  port: 9000

新建Entity:

package com.guxf.demo.entity;

import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;

@Document(collection = "user")
public class User {
    @Id
    private Integer id;
    private String name;
    private int age;

    public User(Integer id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }
//getter和setter方法略
}

package com.guxf.demo.service;

import org.springframework.stereotype.Repository;
import org.springframework.stereotype.Service;

import com.guxf.demo.entity.User;
@Repository
@Service
public interface UserService {
    void save(User user);

    User findByName(String name);
}

package com.guxf.demo.repository;

import org.springframework.data.mongodb.repository.MongoRepository;

import com.guxf.demo.entity.User;

public interface UserRepository extends MongoRepository<User, String> {

    User findByName(String name);
}

package com.guxf.demo.controller;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import com.guxf.demo.entity.User;
import com.guxf.demo.service.UserService;

@RestController
@RequestMapping(value="/com/guxf/demo/entity/User")
public class UserController {
    @Autowired
    private UserService userService;
    @Autowired
    private MongoTemplate mongoTemplate;

    @GetMapping("/save")
    public User save() {
        User user = new User(2, "Tseng", 21);
        mongoTemplate.save(user);
        return user;
    }

    @GetMapping("/find")
    public List<User> find() {
        List<User> userList = mongoTemplate.findAll(User.class);
        return userList;
    }
  
    @GetMapping("/findByName")    
    public User findByName(@RequestParam("name") String name) {        
        User user = userService.findByName(name);        
        return user;    
    }
    }

启动Application,浏览器输入：http://localhost:9000/save