java操作mongodb数据库

1）、 建立MongoDBTest.java，完成简单的mongoDB数据库操作

Mongo mongo = new Mongo('127.0.0.1', 27017);

Mongo mongo = new Mongo();

这样就创建了一个MongoDB的数据库连接对象，它默认连接到当前机器的localhost地址，端口是27017。

2）、连接数据库test

DB db = mongo.getDB(“test”);

这样就获得了一个test的数据库，如果mongoDB中没有创建这个数据库，mongoDB会自动创建当前数据库。

得到了db，下一步我们要获取一个“聚集集合DBCollection”，通过db对象的getCollection方法来完成。

DBCollection users = db.getCollection("users");

这样就获得了一个DBCollection，它相当于我们数据库的“表”。

3）、接下来就可以进行增删改查操作

MongoURI uri = new MongoURI("mongodb://localhost:27017");
String databaseName ="myDatabase";
String collectionName = "mycollections";

Mongo mongo = null;
DB db = null;
DBCollection userCollection;
try {
定义Mongo服务
mongo =new Mongo("localhost", 27017);
mongo = new Mongo(uri);

mongo = new Mongo();
DBAddress addr = new DBAddress("localhost", 27017,databaseName);
mongo.connect(addr);

删除数据库
mongo.dropDatabase(databaseName);

获取databaseName对应的数据库，不存在则自动创建
db = mongo.getDB(databaseName);

添加用户
db.addUser("admin", new char []{'a','d','m','i','n'});

移除用户
db.removeUser("admin");

验证权限
boolean flag = db.authenticate("admin", new char []{'a','d','m','i','n'} );

if(flag == false){
return;
}

设置db为只读 ，只读就不能写入数据了   对save管用，对insert好像不管用
db.setReadOnly(true);

获取collectionName对应的集合，不存在则自动创建
db.createCollection("mycollection", new BasicDBObject());
userCollection = db.getCollection(collectionName);

查询所有的DataBase
for(String dbName : mongo.getDatabaseNames()){
System.out.println("databasename:" + dbName);
}

查询所有的聚集集合
for(String collection :db.getCollectionNames()){
System.out.println("collectionName:" + collection);
}

查询是否存在collectionName集合
if(db.collectionExists(collectionName)){
//去掉重复的数据
List dislist = userCollection.distinct("userId");
int len = dislist.size();
for(int i = 0 ; i< len ; i++){
System.out.println(dislist.get(i));
}

查询
System.out.println(userCollection.find(new BasicDBObject("userId",1)).toArray());

返回前2个
System.out.println(userCollection.find({},{reviews:{slice:2}});                                  //System.out.println("分页："+userCollection.find(new BasicDBObject("",new BasicDBObject("slice", 2))).toArray());

查询所有的数据
DB游标
DBCursor cursor = userCollection.find();
while(cursor.hasNext()){
DBObject userDbobj = cursor.next();             System.out.println("userId:"+userDbobj.get("userId")+";age:"+userDbobj.get("age")+";sex:"+userDbobj.get("sex")+";address:"+userDbobj.get("address"));
}

条件查询
查询age 等于 24
System.out.println("find age = 24: " + userCollection.find(new BasicDBObject("age", 24)).toArray());

查询age 大于等于 24
System.out.println("find age >= 24: " + userCollection.find(new BasicDBObject("age", new BasicDBObject("gte",24))).toArray());

查询age小于等于24            System.out.println("findage<=24:"+userCollection.find(newBasicDBObject("age",newBasicDBObject("lte", 24))).toArray());

查询age 不等于25
System.out.println("查询age!=25：" + userCollection.find(new BasicDBObject("age", new BasicDBObject("$ne", 25))).toArray());

查询某个范围的数据
System.out.println("查询age in 25/26/27：" + userCollection.find(new BasicDBObject("age", new BasicDBObject(QueryOperators.IN, new int[] { 25, 26, 27 }))).toArray());

查询不在某个范围数据
System.out.println("查询age not in 25/26/27：" + userCollection.find(new BasicDBObject("age", new BasicDBObject(QueryOperators.NIN, new int[] { 25, 26, 27 }))).toArray());

按age排序
System.out.println("查询age exists 排序：" + userCollection.find().sort(new BasicDBObject("age",new BasicDBObject(QueryOperators.ORDER_BY, 1))).limit(2).skip(1).toArray());   //(new BasicDBObject("age", new BasicDBObject(QueryOperators.ORDER_BY, 1))).toArray());

new BasicDBObject();

System.out.println("只查询age属性：" + userCollection.find(null, new BasicDBObject("age", true)).toArray());

System.out.println("只查属性：" + userCollection.find(null, new BasicDBObject("age", true), 0, 2).toArray());

System.out.println("只查属性：" + userCollection.find(null, new BasicDBObject("age", true), 0, 2, Bytes.QUERYOPTION_NOTIMEOUT).toArray());
}

添加数据
DBObject user = new BasicDBObject();
user.put("userId", 2);
user.put("userName", "tom");
user.put("age", 21);
user.put("sex", "male");
user.put("address", "北京海淀");

userCollection.save(user);

getN  对save和insert不管用
WriteResult saveResult = userCollection.save(user);
System.out.println(saveResult.getN());
System.out.println(saveResult.isLazy());
if(saveResult.getN() > 0){
System.out.println("添加成功");
}

添加List集合
List<DBObject> list = new ArrayList<DBObject>();
list.add(user);
DBObject user2 = new BasicDBObject();
user2.put("userId", 2);
user2.put("userName", "lily");
user2.put("age", 20);
user2.put("sex", "female");
user2.put("address", "新加坡");
list.add(user2);

userCollection.insert(list);
看是否插入成功
System.out.println("集合中数据量：" + userCollection.count());

删除数据
WriteResult wr = userCollection.remove(new BasicDBObject("userId",1));
System.out.println(wr.getN());
System.out.println(wr.isLazy());
if(wr.getN() > 0){
System.out.println("删除成功！");
}

删除整个集合
userCollection.drop();

修改
DBObject newUser =new  BasicDBObject();
newUser.put("userId", 3);
newUser.put("userName", "tomAndKitty");
newUser.put("age", 25);
user.put("sex", "male");
user.put("address", "北京朝阳");

WriteResult updateResult = userCollection.update(new BasicDBObject("userId",1),newUser);
WriteResult updateResult = userCollection.update(new BasicDBObject("userId",3),newUser,

关闭Mongo服务
if(mongo != null){
mongo.close();
}
db = null;
userCollection = null;
}
}