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Java操作MongoDB数据库的示例代码

作者：黄河大道东　　发布时间：2023-11-23 04:15:51　

标签：Java,MongoDB,数据库

环境准备

step1：创建工程 , 引入依赖

<dependencies>
<dependency>
<groupId>org.mongodb</groupId>
<artifactId>mongodb‐driver</artifactId>
<version>3.6.3</version>
</dependency>
</dependencies>

step2：创建测试类

import com.mongodb.*;
import com.mongodb.client.*;
import com.mongodb.client.model.Filters;
import org.bson.Document;
import org.bson.conversions.Bson;
import org.junit.Test;
import java.util.ArrayList;
import java.util.List;

public class MogoDBTest {

private static MongoClient mongoClient;

static {
System.out.println("===============MongoDBUtil初始化========================");
mongoClient = new MongoClient("127.0.0.1", 27017);
// 大多使用mongodb都在安全内网下，但如果将mongodb设为安全验证模式，就需要在客户端提供用户名和密码：
// boolean auth = db.authenticate(myUserName, myPassword);
MongoClientOptions.Builder options = new MongoClientOptions.Builder();
options.cursorFinalizerEnabled(true);
// 自动重连true
// options.autoConnectRetry(true);
// the maximum auto connect retry time
// 连接池设置为300个连接,默认为100
// options.maxAutoConnectRetryTime(10);
options.connectionsPerHost(300);
// 连接超时，推荐>3000毫秒
options.connectTimeout(30000);
options.maxWaitTime(5000);
// 套接字超时时间，0无限制
options.socketTimeout(0);
// 线程队列数，如果连接线程排满了队列就会抛出“Out of semaphores to get db”错误。
options.threadsAllowedToBlockForConnectionMultiplier(5000);
options.writeConcern(WriteConcern.SAFE);//
options.build();
}

// =================公用用方法=================
/**
* 获取DB实例 - 指定数据库，若不存在则创建
*/
public static MongoDatabase getDB(String dbName) {
if (dbName != null && !"".equals(dbName)) {
MongoDatabase database = mongoClient.getDatabase(dbName);
return database;
}
return null;
}

/**
* 获取指定数据库下的collection对象
*/
public static MongoCollection<Document> getCollection(String dbName, String collName) {
if (null == collName || "".equals(collName)) {
return null;
}
if (null == dbName || "".equals(dbName)) {
return null;
}
MongoCollection<Document> collection = mongoClient
.getDatabase(dbName)
.getCollection(collName);
return collection;
}
}

1.数据库操作

1.1获取所有数据库

//获取所有数据库
@Test
public void getAllDBNames(){
MongoIterable<String> dbNames = mongoClient.listDatabaseNames();
for (String s : dbNames) {
System.out.println(s);
}
}

1.2获取指定库的所有集合名

//获取指定库的所有集合名
@Test
public void getAllCollections(){
MongoIterable<String> colls = getDB("books").listCollectionNames();
for (String s : colls) {
System.out.println(s);
}
}

1.3.删除数据库

//删除数据库
@Test
public void dropDB(){
//连接到数据库
MongoDatabase mongoDatabase = getDB("test");
mongoDatabase.drop();
}

2.文档操作

2.1插入文档

1.插入单个文档

//插入一个文档
@Test
public void insertOneTest(){
//获取集合
MongoCollection<Document> collection = getCollection("books","book");
//要插入的数据
Document document = new Document("id",1)
.append("name", "哈姆雷特")
.append("price", 67);
//插入一个文档
collection.insertOne(document);
System.out.println(document.get("_id"));
}

2.插入多个文档

//插入多个文档
@Test
public void insertManyTest(){
//获取集合
MongoCollection<Document> collection = getCollection("books","book");
//要插入的数据
List<Document> list = new ArrayList<>();
for(int i = 1; i <= 15; i++) {
Document document = new Document("id",i)
.append("name", "book"+i)
.append("price", 20+i);
list.add(document);
}
//插入多个文档
collection.insertMany(list);
}

2.2查询文档

2.2.1基本查询

1.查询集合所有文档

@Test
public void findAllTest(){
//获取集合
MongoCollection<Document> collection = getCollection("books","book");
//查询集合的所有文档
FindIterable findIterable= collection.find();
MongoCursor cursor = findIterable.iterator();
while (cursor.hasNext()) {
System.out.println(cursor.next());
}
}

2.条件查询

@Test
public void findConditionTest(){
//获取集合
MongoCollection<Document> collection = getCollection("books","book");
//方法1.构建BasicDBObject 查询条件 id大于2，小于5
BasicDBObject queryCondition=new BasicDBObject();
queryCondition.put("id", new BasicDBObject("$gt", 2));
queryCondition.put("id", new BasicDBObject("$lt", 5));
//查询集合的所有文通过price升序排序
FindIterable findIterable= collection.find(queryCondition).sort(new BasicDBObject("price",1));

//方法2.通过过滤器Filters，Filters提供了一系列查询条件的静态方法，id大于2小于5，通过id升序排序查询
//Bson filter=Filters.and(Filters.gt("id", 2),Filters.lt("id", 5));
//FindIterable findIterable= collection.find(filter).sort(Sorts.orderBy(Sorts.ascending("id")));

//查询集合的所有文
MongoCursor cursor = findIterable.iterator();
while (cursor.hasNext()) {
System.out.println(cursor.next());
}
}

2.2.2 投影查询

@Test
public void findAllTest3(){
//获取集合
MongoCollection<Document> collection = getCollection("books","book");
//查询id等于1,2,3,4的文档
Bson fileter=Filters.in("id",1,2,3,4);
//查询集合的所有文档
FindIterable findIterable= collection.find(fileter).projection(new BasicDBObject("id",1).append("name",1).append("_id",0));
MongoCursor cursor = findIterable.iterator();
while (cursor.hasNext()) {
System.out.println(cursor.next());
}
}

2.3分页查询

2.3.1.统计查询

//集合的文档数统计
@Test
public void getCountTest() {
//获取集合
MongoCollection<Document> collection = getCollection("books","book");
//获取集合的文档数
Bson filter = Filters.gt("price", 30);
int count = (int)collection.count(filter);
System.out.println("价钱大于30的count==："+count);
}

2.3.2分页列表查询

//分页查询
@Test
public void findByPageTest(){
//获取集合
MongoCollection<Document> collection = getCollection("books","book");
//分页查询跳过0条，返回前10条
FindIterable findIterable= collection.find().skip(0).limit(10);
MongoCursor cursor = findIterable.iterator();
while (cursor.hasNext()) {
System.out.println(cursor.next());
}
System.out.println("----------取出查询到的第一个文档-----------------");
//取出查询到的第一个文档
Document document = (Document) findIterable.first();
//打印输出
System.out.println(document);
}

2.4修改文档

//修改文档
@Test
public void updateTest(){
//获取集合
MongoCollection<Document> collection = getCollection("books","book");
//修改id=2的文档通过过滤器Filters，Filters提供了一系列查询条件的静态方法
Bson filter = Filters.eq("id", 2);
//指定修改的更新文档
Document document = new Document("$set", new Document("price", 44));
//修改单个文档
collection.updateOne(filter, document);
//修改多个文档
// collection.updateMany(filter, document);
//修改全部文档
//collection.updateMany(new BasicDBObject(),document);
}

2.5 删除文档

//删除与筛选器匹配的单个文档
@Test
public void deleteOneTest(){
//获取集合
MongoCollection<Document> collection = getCollection("books","book");
//申明删除条件
Bson filter = Filters.eq("id",3);
//删除与筛选器匹配的单个文档
collection.deleteOne(filter);

//删除与筛选器匹配的所有文档
// collection.deleteMany(filter);

System.out.println("--------删除所有文档----------");
//删除所有文档
// collection.deleteMany(new Document());
}

来源：https://www.cnblogs.com/hhddd-1024/p/14686366.html

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