MongoDb(1)Java连接MongoDb数据库
/*
* This Java source file was generated by the Gradle 'init' task.
*/
package connectMongoDb;
import org.bson.Document;
import org.bson.conversions.Bson;
import com.mongodb.MongoClient;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.model.*;
/**
* <p>Java连接MongoDb数据库</p>
* @author lius
*
*/
public class Library implements AutoCloseable {
private static MongoClient mClient = null;
public static void main(String[] args) {
//创建实例
Library library = new Library();
//执行实例类start方法
library.start();
}
private void start() {
//连接本地Mongo服务
MongoClient mClient = new MongoClient("127.0.0.1");
//获取指定的数据库
MongoDatabase dataBase = mClient.getDatabase("admin");
//判断是否存在“a”collection,不存在就创建
if(dataBase.getCollection("a")==null) {
dataBase.createCollection("a");
}
//获取指定的collection
MongoCollection<Document> coll = dataBase.getCollection("a");
//判断该collection不存在数据就创建
if(coll.count()<=0) {
coll.insertOne(new Document("name","tom").append("sex", "F"));
}
//查询collection下“sex”值为“F”的数据，并将返回的数据集合作为迭代器
MongoCursor<Document> fs = coll.find(Filters.eq("sex","F")).iterator();
//打印输出collection下的数据量的统计值
System.out.println(coll.count());
//循环遍历打印迭代器迭代出的每一个Document，并将Document的数据以Json的形式展现
while(fs.hasNext()) {
System.out.println(fs.next().toJson());
}
}
//实现AutoCloseAble接口，实现实例销毁自动执行close方法
@Override
public void close() throws Exception {
// TODO Auto-generated method stub
System.out.println("into...close:");
if(mClient!=null) {
mClient.close();
System.out.println("close:"+mClient);
}
}
}
