java操作mongodb获取记录数_Java操作MongoDB的常见API
package com.jadyer.test;
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.List;
import org.bson.types.ObjectId;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.MongoClient;
import com.mongodb.WriteResult;
import com.mongodb.util.JSON;
/**
* mongoDB-2.6的Java驱动测试
* @see ----------------------------------------------------------------------------------------
* @see 这里要用到mongoDB的Java驱动包，下载地址http://docs.mongodb.org/ecosystem/drivers/java/
* @see ----------------------------------------------------------------------------------------
* Created by 玄玉 on 2014/05/15 22:17.
*/
public class MongoDBTest {
private static MongoClient mongoClient;
private static DB db;
/**
* 建立数据库连接
*/
@BeforeClass
public static void globalInit(){
try {
//mongoClient = new MongoClient(Arrays.asList(new ServerAddress("127.0.0.1", 27017), new ServerAddress("127.0.0.1", 27018), new ServerAddress("127.0.0.1", 27019)));
mongoClient = new MongoClient("127.0.0.1", 27017);
} catch (UnknownHostException e) {
System.err.println("mongoDB主机地址有误");
}
db = mongoClient.getDB("mydemo");
}
/**
* 销毁数据库连接
*/
@AfterClass
public static void globalDestroy(){
mongoClient.close();
}
/**
* 获取数据库信息
*/
@Test
public void getMetaData(){
//查询数据库中所有的集合名称
for(String collectionName : db.getCollectionNames()){
System.out.println("mydemo数据库所拥有的集合为:[" + collectionName + "]");
}
//查询某一集合中的数据
DBCollection collection = db.getCollection("person");
DBCursor cursor = collection.find();
try{
while(cursor.hasNext()){
System.out.println("person集合所拥有的name为--[" + cursor.next().get("name") + "]");
}
}finally{
cursor.close();
}
System.out.println("person集合中的记录数为----------->" + cursor.count());
System.out.println("person集合数据格式化后的JSON串为-->" + JSON.serialize(cursor));
}
/**
* 创建一个空的"moive"集合
*/
@Test
public void createCollection(){
db.createCollection("movie", new BasicDBObject());
}
/**
* 为"moive"集合添加文档
*/
@Test
public void insertDocument(){
DBObject doc = new BasicDBObject();
doc.put("name", "24");
doc.put("season", "ninth");
doc.put("score", 88);
List actorList = new ArrayList();
actorList.add("Jack Bauer");
actorList.add("Counter Terrorist Unit");
doc.put("actor", actorList);
db.getCollection("movie").insert(doc);
}
/**
* 批量插入文档
*/
@Test
public void insertBatchDocument(){
List docList = new ArrayList();
DBObject doc11 = new BasicDBObject("name", "Prison Break").append("season", "fourth").append("score", 99);
DBObject doc22 = new BasicDBObject("name", "Game of Thrones").append("season", "third").append("score", 92);
docList.add(doc11);
docList.add(doc22);
db.getCollection("movie").insert(docList);
}
/**
* 根据_id删除数据
*/
@Test
public void deleteById(){
WriteResult result = db.getCollection("movie").remove(new BasicDBObject("_id", new ObjectId("5374c6dc5030e0ea4dac8907")));
System.out.println("本次操作影响的记录条数为:" + result.getN());
}
/**
* 根据条件删除数据
*/
@Test
public void deleteByData(){
DBObject doc = new BasicDBObject();
doc.put("name", "Prison Break");
WriteResult result = db.getCollection("movie").remove(doc);
System.out.println("本次操作影响的记录条数为:" + result.getN());
}
/**
* 更新数据
* @see 增加email属性
*/
@Test
public void update(){
DBObject doc = new BasicDBObject();
doc.put("$set", new BasicDBObject("email", "[email protected]"));
WriteResult result = db.getCollection("movie").update(new BasicDBObject(), doc, false, true);
System.out.println("本次操作影响的记录条数为:" + result.getN());
}
/**
* 查询"moive"集合中的key
*/
@Test
public void getKey(){
DBObject keys = new BasicDBObject();
keys.put("_id", false);
keys.put("name", true);
//keys.put("score", true);
//第一个参数表示查询条件,第二个参数表示返回的具体key
DBCursor cursor = db.getCollection("movie").find(null, keys);
try{
while(cursor.hasNext()){
DBObject object = cursor.next();
System.out.println("查询到的name=" + object.get("name") + ", score=" + object.get("score"));
}
}finally{
cursor.close();
}
}
/**
* 查询"moive"集合中分数不超过95的key
*/
@Test
public void getKeyUseScore(){
DBObject ref = new BasicDBObject();
ref.put("score", new BasicDBObject("$lte", 95));
DBCursor cursor = db.getCollection("movie").find(ref, null);
try{
while(cursor.hasNext()){
DBObject object = cursor.next();
System.out.println("查询到的name=" + object.get("name") + ", score=" + object.get("score"));
}
}finally{
cursor.close();
}
}
/**
* 分页查询
*/
@Test
public void limitSkip(){
DBCursor cursor = db.getCollection("movie").find(null, null);
cursor.limit(0).skip(1);
try{
while(cursor.hasNext()){
DBObject object = cursor.next();
System.out.println("查询到的name=" + object.get("name"));
}
}finally{
cursor.close();
}
}
}