Spring Boot 连接MongonDB 配置和测试

        首先，先讲一下mongondb为nosql的一些特性，mongoDB 是一种文档性的数据库。先解释一下文档的数据库，即可以存放xml、json、bson类型系那个的数据。这些数据具备自述性（self-describing），呈现分层的树状数据结构。redis可以用hash存放简单关系型数据。
mongoDB 存放json格式数据。

适合场景：事件记录、内容管理或者博客平台，比如评论系统。

mongodb与mysql不同，mysql的每一次更新操作都会直接写入硬盘，但是mongo不会，做为内存型数据库，数据操作会先写入内存，然后再会持久化到硬盘中去，那么mongo是如何持久化的呢

mongodb在启动时，专门初始化一个线程不断循环（除非应用crash掉），用于在一定时间周期内来从defer队列中获取要持久化的数据并写入到磁盘的journal(日志)和mongofile(数据)处，当然因为它不是在用户添加记录时就写到磁盘上，所以按mongodb开发者说，它不会造成性能上的损耗，因为看过代码发现，当进行CUD操作时，记录(Record类型)都被放入到defer队列中以供延时批量（groupcommit）提交写入，但相信其中时间周期参数是个要认真考量的参数，系统为90毫秒，如果该值更低的话，可能会造成频繁磁盘操作，过高又会造成系统宕机时数据丢失过。

下面就记录一下在spring boot中怎么配置和连接mongodb

1.pom.xml

xml version="1.0" encoding="UTF-8"?>
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">
    4.0.0

    com.mongodb.demo
    mongodbdemo
    0.0.1-SNAPSHOT
    jar

    mongodbdemo
    Demo project for Spring Boot

    
        org.springframework.boot
        spring-boot-starter-parent
        1.5.12.RELEASE
         
    

    
        UTF-8
        UTF-8
        1.8
    

    
        
            org.springframework.boot
            spring-boot-starter-test
            test
        

        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-data-mongodb
        
        
            org.springframework.boot
            spring-boot-devtools
            true
            true
        
        
            com.alibaba
            fastjson
            1.2.38
        
        
            org.springframework.boot
            spring-boot-starter-freemarker
        

        
            junit
            junit
            3.8.1
            test
        
        
            org.junit.jupiter
            junit-jupiter-api
            RELEASE
        
        
            junit
            junit
            RELEASE
        
    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

2.在classpath下加上application.properties ,文件中加上以下内容

spring.application.name=mongodbdemo
# mongodb
spring.data.mongodb.uri=mongodb://appuser:[email protected]:27017/paas_message_center

3.实体类

package com.mongodb.demo.mongodbdemo.domain;

import java.io.Serializable;

public class User implements Serializable {
    private static final long serialVersionUID = -3258839839160856613L;
    private Long id;
    private String userName;
    private String passWord;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getPassWord() {
        return passWord;
    }

    public void setPassWord(String passWord) {
        this.passWord = passWord;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", userName='" + userName + '\'' +
                ", passWord='" + passWord + '\'' +
                '}';
    }
}

4.Dao

package com.mongodb.demo.mongodbdemo.dao;

import com.mongodb.demo.mongodbdemo.domain.User;

import java.util.List;

public interface UserDao {
    public void saveUser(User user);

    public User findUserById(long id);

    public User findUserByUserName(String userName);

    public void updateUser(User user);

    public void deleteUserById(Long id);

    public List findAll(int pageNo, int pageSize);

    public List list();
}

package com.mongodb.demo.mongodbdemo.dao.impl;

import com.mongodb.demo.mongodbdemo.dao.UserDao;
import com.mongodb.demo.mongodbdemo.domain.User;
import org.springframework.data.domain.Sort;
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.Service;

import javax.annotation.Resource;
import java.util.List;

@Service("userDao")
public class UserDaoImpl  implements UserDao{

    @Resource
    private MongoTemplate mongoTemplate;

    @Override
    public void saveUser(User user) {
        mongoTemplate.save(user);
    }

    @Override
    public User findUserById(long id) {
        Query query = new Query(Criteria.where("id").is(id));
        return mongoTemplate.findOne(query,User.class);
    }

    @Override
    public User findUserByUserName(String userName) {
        Query query = new Query(Criteria.where("userName").is(userName));
        User user =  mongoTemplate.findOne(query , User.class);
        return user;
    }

    @Override
    public void updateUser(User user) {
        Query query=new Query(Criteria.where("id").is(user.getId()));
        Update update= new Update().set("userName", user.getUserName()).set("passWord", user.getPassWord());
        //更新查询返回结果集的第一条
        mongoTemplate.updateFirst(query,update,User.class);
        //更新查询返回结果集的所有
        // mongoTemplate.updateMulti(query,update,User.class);
    }

    @Override
    public void deleteUserById(Long id) {
        Query query=new Query(Criteria.where("id").is(id));
        mongoTemplate.remove(query,User.class);
    }

    @Override
    public List findAll(int pageNo, int pageSize) {
        Query query = new Query();
        query.skip((pageNo - 1) * pageSize);
        query.limit(pageSize);
        query.with(new Sort(new Sort.Order(Sort.Direction.ASC, "userId")));//按照userId排序
        List users = mongoTemplate.find(query,User.class);
        return users;
    }

    @Override
    public List list() {
        Query query = new Query();
        List users = mongoTemplate.find(query,User.class);
        return users;
    }
}

5.创建测试类

package com.mongodb.demo.mongodbdemo;

import com.mongodb.demo.mongodbdemo.dao.UserDao;
import com.mongodb.demo.mongodbdemo.domain.User;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import javax.annotation.Resource;
import java.util.List;

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserDaoTest {

    @Resource
    private UserDao userDao;

    @Test
    public void testSaveUser() throws Exception {
        User user=new User();
        user.setId(3L);
        user.setUserName("小彭");
        user.setPassWord("123456");
        userDao.saveUser(user);
    }

    @Test
    public void findUserByUserName(){
        User user= userDao.findUserByUserName("小王");
        System.out.println("user is "+user);
    }

    @Test
    public void updateUser(){
        User user=new User();
        user.setId(2l);
        user.setUserName("天空");
        user.setPassWord("fffxxxx");
        userDao.updateUser(user);
    }

    @Test
    public void deleteUserById(){
        userDao.deleteUserById(1l);
    }

    @Test
    public void listTest() {
        List users =  userDao.list();
        System.out.println(users.size());
        for(User user:users) {
            System.out.println(user.toString());
        }
    }

    @Test
    public void findUserByIdTest() {
        User user = userDao.findUserById(1L);
        System.out.println(user.toString());
    }
}

在虚拟机中安装MongonDB ，docker安装命令如下：

docker pull mongo:3.4.9
docker run -p 27017:27017 --name mongodb -d mongo:3.4.9 --auth
docker exec -it mongodb mongo admin
db.createUser({user:"root",pwd:"123456",roles:["root"]});
#创建数据库存
paas_message_center
appuser
123456