首先需要下载MongoDB JavaDriver，我一开始以为mongo-java-driver-2.9.3.jar是最新版，后来才发现MongoDB JavaDriver下载页面版本排序是按照文件名而不是按照日期排序，其实mongo-java-driver-2.12.0.jar是最新版。因为从版本2.10.0开始提供新的类MongoClient而不是Mongo来连接数据库，所以需要注意所使用的MongoDB Java Driver版本。 Java代码如下：
package com.yqu.mongodb;
import java.net.UnknownHostException;
import java.util.List;
import java.util.Set;
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.MongoClientURI;
import com.mongodb.MongoException;
public class HelloMongoDB {
public static void main(String[] args) {
MongoClient mongoClient = null;
try {
// Since 2.10.0, uses MongoClient
// mongoClient = new MongoClient("localhost", 27017);
String host = "mongodb://localhost:27017";
mongoClient = new MongoClient(new MongoClientURI(host));
showdbs(mongoClient);
// MongoDB will create it if database doesn't exists
DB db = mongoClient.getDB("hellodb");
System.out.println("\nget database 'hellodb'.");
showdbs(mongoClient);
showcollections(db);
DBCollection coll = null;
// MongoDB will create it if collection doesn't exists
// There is a difference:
// showcollections display the new collection name when
// createCollection is used,
// but not before any document is inserted when
// getCollection is used.
//
// coll = db.createCollection("helloCollection",
// new BasicDBObject("capped", false));
coll = db.getCollection("helloCollection");
System.out.println("\nget collection 'helloCollection'.");
showcollections(db);
BasicDBObject doc, query;
doc = new BasicDBObject("name", "MongoDB")
.append("type", "database")
.append("count", 1)
.append("info", new BasicDBObject("x", 123)
.append("y", 321));
coll.insert(doc);
doc = new BasicDBObject("name", "Java")
.append("type", "language")
.append("count", 3)
.append("info", new BasicDBObject("x", 76)
.append("y", 265));
coll.insert(doc);
doc = new BasicDBObject("name", "Python")
.append("type", "language")
.append("count", 5)
.append("info", new BasicDBObject("x", 2)
.append("y", 2014));
coll.insert(doc);
coll.createIndex(new BasicDBObject("name", "text"));
coll.createIndex(new BasicDBObject("count", 1));
System.out.println("\nSome document are inserted.");
showdocuments(coll);
searchdocuments(coll, new BasicDBObject("name", "MongoDB"));
searchdocuments(coll, new BasicDBObject("count",
new BasicDBObject("$lt", 4)));
// The embedded document query example
searchdocuments(coll, new BasicDBObject("info.x",
new BasicDBObject("$lt", 100)));
// update document which name is 'Java'
query = new BasicDBObject("name", "Java");
BasicDBObject newDoc = new BasicDBObject("name", "R");
BasicDBObject updateObj = new BasicDBObject("$set", newDoc);
coll.update(query, updateObj);
System.out.println("\nUpdate document which name is 'Java'");
showdocuments(coll);
showindexs(coll);
showcollections(db);
mongoClient.dropDatabase("hellodb");
System.out.println("drop database 'hellodb'.");
showdbs(mongoClient);
} catch (UnknownHostException e) {
e.printStackTrace();
} catch (MongoException e) {
e.printStackTrace();
} finally {
if (mongoClient != null) {
mongoClient.close();
}
}
}
private static void showdbs(MongoClient mongoClient) {
System.out.println("\nCurrent databases:");
List dbs = mongoClient.getDatabaseNames();
if (dbs.isEmpty())
System.out.println();
else {
for (String s : dbs) {
System.out.println(" " + s);
}
}
}
private static void showcollections(DB db) {
System.out.println("\nCurrent collections under " +
db.getName() + ":");
Set collections = db.getCollectionNames();
if (collections.isEmpty())
System.out.println();
else {
for (String s : collections) {
System.out.println(" " + s);
}
}
}
private static void showdocuments(DBCollection coll) {
System.out.println("\nCurrent documents under " +
coll.getName() + ":");
DBCursor cur = coll.find();
while (cur.hasNext()) {
System.out.println(" " + cur.next());
}
}
private static void showindexs(DBCollection coll) {
System.out.println("\nCurrent index info under " +
coll.getName() + ":");
List list = coll.getIndexInfo();
for (DBObject o : list) {
System.out.println(o.get("key"));
}
}
private static void searchdocuments(
DBCollection coll, BasicDBObject query) {
System.out.println("\nQuery " + query +
" for " + coll.getName() + ":");
DBCursor cur = coll.find(query);
while (cur.hasNext()) {
System.out.println(" " + cur.next());
}
}
}
输出：
Current databases:
local
admin
test
get database 'hellodb'.
Current databases:
local
admin
test
Current collections under hellodb:
get collection 'helloCollection'.
Current collections under hellodb:
Some document are inserted.
Current documents under helloCollection:
{ "_id" : { "$oid" : "5336644eb767266396077ff8"} , "name" : "MongoDB" , "type" : "database" , "count" : 1 , "info" : { "x" : 123 , "y" : 321}}
{ "_id" : { "$oid" : "5336644eb767266396077ff9"} , "name" : "Java" , "type" : "language" , "count" : 3 , "info" : { "x" : 76 , "y" : 265}}
{ "_id" : { "$oid" : "5336644eb767266396077ffa"} , "name" : "Python" , "type" : "language" , "count" : 5 , "info" : { "x" : 2 , "y" : 2014}}
Query { "name" : "MongoDB"} for helloCollection:
{ "_id" : { "$oid" : "5336644eb767266396077ff8"} , "name" : "MongoDB" , "type" : "database" , "count" : 1 , "info" : { "x" : 123 , "y" : 321}}
Query { "count" : { "$lt" : 4}} for helloCollection:
{ "_id" : { "$oid" : "5336644eb767266396077ff8"} , "name" : "MongoDB" , "type" : "database" , "count" : 1 , "info" : { "x" : 123 , "y" : 321}}
{ "_id" : { "$oid" : "5336644eb767266396077ff9"} , "name" : "Java" , "type" : "language" , "count" : 3 , "info" : { "x" : 76 , "y" : 265}}
Query { "info.x" : { "$lt" : 100}} for helloCollection:
{ "_id" : { "$oid" : "5336644eb767266396077ff9"} , "name" : "Java" , "type" : "language" , "count" : 3 , "info" : { "x" : 76 , "y" : 265}}
{ "_id" : { "$oid" : "5336644eb767266396077ffa"} , "name" : "Python" , "type" : "language" , "count" : 5 , "info" : { "x" : 2 , "y" : 2014}}
update document which name is 'Java'
Current documents under helloCollection:
{ "_id" : { "$oid" : "5336644eb767266396077ff8"} , "name" : "MongoDB" , "type" : "database" , "count" : 1 , "info" : { "x" : 123 , "y" : 321}}
{ "_id" : { "$oid" : "5336644eb767266396077ff9"} , "name" : "R" , "type" : "language" , "count" : 3 , "info" : { "x" : 76 , "y" : 265}}
{ "_id" : { "$oid" : "5336644eb767266396077ffa"} , "name" : "Python" , "type" : "language" , "count" : 5 , "info" : { "x" : 2 , "y" : 2014}}
Current index info under helloCollection:
{ "_id" : 1}
{ "_fts" : "text" , "_ftsx" : 1}
{ "count" : 1}
Current collections under hellodb:
helloCollection
system.indexes
drop database 'hellodb'.
Current databases:
local
admin
test参考
Getting Started with Java Driver
MongoDB Drivers
MongoDB Driver Syntax Table
MongoDB Java Driver API Document