一、Java 实现对 MongDB 的操作
1、前提条件
除了通过启动 mongo 进程进如 Shell 环境访问数据库外，MongoDB 还提供了其他基于编程语言的访问数据库方法。MongoDB 官方提供了 Java 语言的驱动包，利用这些驱动包可使用多种编程方法来连接并操作 MongoDB 数据库。
想要在 Java 程序中使用 MongoDB，需要确保您的电脑上已经安装了 MongoDB，并搭建好了 Java 的环境。
2、添加依赖
在 Maven 中添加以下依赖来使用操作 MongoDB 数据库：
<dependencies>
<dependency>
<groupId>org.mongodb</groupId>
<artifactId>bson</artifactId>
<version>3.12.11</version>
</dependency>
<dependency>
<groupId>org.mongodb</groupId>
<artifactId>mongodb-driver</artifactId>
<version>3.12.11</version>
</dependency>
<dependency>
<groupId>org.mongodb</groupId>
<artifactId>mongodb-driver-core</artifactId>
<version>3.12.11</version>
</dependency>
...
</dependencies>
二、Java 操作 MongoDB 数据库 Demo
1、连接数据库
package com.db.demo;
import com.mongodb.client.MongoDatabase;
import com.mongodb.MongoClient;
import com.mongodb.MongoCredential;
/**
* @version 1.0.0
* @description 连接数据库
**/
public class ConnectToMongodb {
public static void main(String[] args) {
// 创建 MongoDB 连接
MongoClient mongo = new MongoClient("localhost", 27017);
// 连接到 MongoDB
MongoCredential credential = MongoCredential.createCredential("study", "study", "password".toCharArray());
System.out.println("Credentials ::" + credential);
// 访问数据库
MongoDatabase database = mongo.getDatabase("study");
System.out.println("Connect to database successfully!");
System.out.println("MongoDatabase info is : " + database.getName());
}
}
运行 Main 函数，返回以下结果：
Credentials ::MongoCredential{mechanism=null, userName=‘study’, source=‘study’, password=, mechanismProperties=}
Connect to database successfully!
MongoDatabase info is : study2、创建集合
package com.db.demo;
import com.mongodb.client.MongoDatabase;
import com.mongodb.MongoClient;
import com.mongodb.MongoCredential;
/**
* @version 1.0.0
* @description 创建集合
**/
public class CreatingCollection {
public static void main(String[] args) {
// 创建 MongoDB 连接
MongoClient mongo = new MongoClient("localhost", 27017);
// 连接到 MongoDB
MongoCredential credential = MongoCredential.createCredential("study", "study", "password".toCharArray());
System.out.println("Credentials ::" + credential);
// 访问数据库
MongoDatabase database = mongo.getDatabase("study");
System.out.println("Connect to database successfully!");
System.out.println("MongoDatabase info is : " + database.getName());
// 创建集合
database.createCollection("study_test_3");
System.out.println("create collection successfully!");
}
}
运行 Main 函数，返回以下结果：
Credentials ::MongoCredential{mechanism=null, userName=‘study’, source=‘study’, password=, mechanismProperties=}
Connect to database successfully!
MongoDatabase info is : study
create collection successfully!3、列出所有集合
public static void main(String[] args) {
// 创建 MongoDB 连接
MongoClient mongo = new MongoClient("localhost", 27017);
// 连接到 MongoDB
MongoCredential credential = MongoCredential.createCredential("study", "study", "password".toCharArray());
System.out.println("Credentials ::" + credential);
// 访问数据库
MongoDatabase database = mongo.getDatabase("study");
System.out.println("Connect to database successfully!");
System.out.println("MongoDatabase info is : " + database.getName());
// 检索集合列表
for (String name : database.listCollectionNames()) {
System.out.println(name);
}
}运行 Main 函数，返回以下结果：
Credentials ::MongoCredential{mechanism=null, userName=‘study’, source=‘study’, password=, mechanismProperties=}
Connect to database successfully!
MongoDatabase info is : study
study
study_test_3
study_test_24、获取/选择集合
.....
// 创建集合
MongoCollection<Document> collection = database.getCollection("study");
System.out.println("chose collection : " + collection.getNamespace());
.....运行 Main 函数，返回以下结果：
chose collection : study.study5、插入文档
public static void main(String[] args) {
// 创建 MongoDB 连接
MongoClient mongo = new MongoClient("localhost", 27017);
// 连接到 MongoDB
MongoCredential credential = MongoCredential.createCredential("study", "study", "password".toCharArray());
System.out.println("Credentials ::" + credential);
// 访问数据库
MongoDatabase database = mongo.getDatabase("study");
System.out.println("Connect to database successfully!");
System.out.println("MongoDatabase info is : " + database.getName());
// 检索集合
MongoCollection<Document> collection = database.getCollection("study");
System.out.println("chose collection : " + collection.getNamespace());
Document document = new Document("title", "MongoDB")
.append("description", "database")
.append("likes", 200)
.append("url", "https://study.xxx.xx/")
.append("by", "study");
// 将文档插入到集合中
collection.insertOne(document);
System.out.println("Document insert successfully!");
}运行 Main 函数，返回以下结果：
Credentials ::MongoCredential{mechanism=null, userName=‘study’, source=‘study’, password=, mechanismProperties=}
Connect to database successfully!
MongoDatabase info is : study
chose collection : study.study
Document insert successfully!6、查询文档
....
// 获取 iterable 对象
FindIterable<Document> iterDoc = collection.find();
int i = 1;
// 获取迭代器
for (Document document : iterDoc) {
System.out.println(document);
i++;
}
.......7、更新文档
.....
// 更新单个可用 updateOne
collection.updateMany(Filters.eq("title", "MongoDB"), Updates.set("likes", 150));
System.out.println("Document update successfully...");
// 更新后检索文档
// 获取 iterable 对象
FindIterable<Document> iterDoc = collection.find();
int i = 1;
// 获取迭代器
for (Document document : iterDoc) {
System.out.println(document);
i++;
}
......8、删除文档
......
// 删除文档 删除多个可用 deleteMany
collection.deleteOne(Filters.eq("title", "MongoDB"));
System.out.println("Document delete successfully...");
// 删除后检索文档
// 获取 iterable 对象
FindIterable<Document> iterDoc = collection.find();
int i = 1;
// 获取迭代器
for (Document document : iterDoc) {
System.out.println(document);
i++;
}
......9、删除集合
......
// 删除集合
collection.drop();
System.out.println("drop collection : " + collection.getNamespace());
.....