Centos8安装MongoDB 4.2

cd /opt 
wget -O mongodb-linux-x86_64-rhel80-4.2.3.tgz https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-rhel80-4.2.3.tgz
tar -zxvf mongodb-linux-x86_64-rhel80-4.2.3.tgz  
ln -s mongodb-linux-x86_64-rhel80-4.2.3 mongodb

useradd mongod
mkdir -p /var/lib/mongo
chown -R mongod:mongod /opt/mongodb*
chown -R mongod: /var/lib/mongo

vim /etc/mongod.conf
#内容如下
storage:
  dbPath: "/var/lib/mongo"
  journal:
    enabled: true

net:
  port: 27017
  bindIp: "127.0.0.1"

vim /etc/systemd/system/mongod.service
#内容如下
[Unit]
Description=MongoDB
After=syslog.target network.target

[Service]
Type=simple

User=mongod
Group=mongod

ExecStart=/opt/mongodb/bin/mongod --config /etc/mongod.conf

[Install]
WantedBy=multi-user.target

vim /etc/profile.d/mongodb.sh
#内容如下
## mongodb
PATH=$PATH:/opt/mongodb/bin

systemctl daemon-reload
systemctl start mongod
systemctl status mongod

# 使环境变量生效
. /etc/profile.d/mongodb.sh
mongo

MongoDB shell version v4.2.3
connecting to: mongodb://127.0.0.1:27017/?compressors=disabled&gssapiServiceName=mongodb
Implicit session: session { "id" : UUID("04c11ecc-5ae4-4f8f-a81b-bb2c2595126d") }
MongoDB server version: 4.2.3
Server has startup warnings: 
2020-02-11T16:02:25.696+0800 I  CONTROL  [initandlisten] 
2020-02-11T16:02:25.696+0800 I  CONTROL  [initandlisten] ** WARNING: Access control is not enabled for the database.
2020-02-11T16:02:25.696+0800 I  CONTROL  [initandlisten] **          Read and write access to data and configuration is unrestricted.
2020-02-11T16:02:25.696+0800 I  CONTROL  [initandlisten] 
2020-02-11T16:02:25.696+0800 I  CONTROL  [initandlisten] 
2020-02-11T16:02:25.696+0800 I  CONTROL  [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is 'always'.
2020-02-11T16:02:25.696+0800 I  CONTROL  [initandlisten] **        We suggest setting it to 'never'
2020-02-11T16:02:25.696+0800 I  CONTROL  [initandlisten] 
---
Enable MongoDB's free cloud-based monitoring service, which will then receive and display
metrics about your deployment (disk utilization, CPU, operation statistics, etc).

The monitoring data will be available on a MongoDB website with a unique URL accessible to you
and anyone you share the URL with. MongoDB may use this information to make product
improvements and to suggest MongoDB products and deployment options to you.

To enable free monitoring, run the following command: db.enableFreeMonitoring()
To permanently disable this reminder, run the following command: db.disableFreeMonitoring()
---

> db
test
> use test
switched to db test
> 

use admin

db.createUser(
  {
    user: "superuser",
    pwd: "changeMeToAStrongPassword",
    roles: [ "root" ]
  }
)

show users

# {
#    "_id" : "admin.superuser",
#    "userId" : UUID("7c2aee5c-6af5-4e25-ae0f-4422c6a8a03c"),
#    "user" : "superuser",
#    "db" : "admin",
#    "roles" : [
#            {
#              "role" : "root",
#              "db" : "admin"
#            }
#    ],
#    "mechanisms" : [
#            "SCRAM-SHA-1",
#            "SCRAM-SHA-256"
#    ]
#  }

db.shutdownServer() #关闭
exit

<dependency>
  <groupId>org.mongodb</groupId>
  <artifactId>mongodb-driver-sync</artifactId>
  <version>3.12.1</version>
</dependency>

        final String uriString = "mongodb://superuser:changeMeToAStrongPassword@arloor.com:27017/";
        MongoClient mongoClient = MongoClients.create(uriString);
        //展示所有数据库
        MongoCursor<String> iterator = mongoClient.listDatabaseNames().iterator();
        while (iterator.hasNext()){
            String next = iterator.next();
            System.out.println(next);
        }

        MongoDatabase database = mongoClient.getDatabase("test");
        MongoCollection<Document> collection = database.getCollection("a");
        Document doc = new Document("name", "MongoDB")
                .append("type", "database")
                .append("count", 1)
                .append("versions", Arrays.asList("v3.2", "v3.0", "v2.6"))
                .append("info", new Document("x", 203).append("y", 102));
        collection.insertOne(doc);