【MongoDB for Java】Java操作MongoDB

[code]packagecom.hoo.test;

importjava.net.UnknownHostException;

importcom.mongodb.DB;

importcom.mongodb.DBCollection;

importcom.mongodb.DBCursor;

importcom.mongodb.Mongo;

importcom.mongodb.MongoException;

importcom.mongodb.util.JSON;

/**

*<b>function:</b>MongoDB简单示例

*@authorhoojo

*@createDate2011-5-24下午02:42:29

*@fileSimpleTest.java

*@packagecom.hoo.test

*@projectMongoDB

*@blog
'target='_blank'>http://blog.csdn.net/IBM_hoojo
*@emailhoojo_@126.com
*@version1.0
*/
publicclassSimpleTest{
publicstaticvoidmain(String[]args)throwsUnknownHostException,MongoException{
Mongomg=newMongo();
//查询所有的Database
for(Stringname:mg.getDatabaseNames()){
System.out.println("dbName:"+name);
}
DBdb=mg.getDB("test");
//查询所有的聚集集合
for(Stringname:db.getCollectionNames()){
System.out.println("collectionName:"+name);
}
DBCollectionusers=db.getCollection("users");
//查询所有的数据
DBCursorcur=users.find();
while(cur.hasNext()){
System.out.println(cur.next());
}
System.out.println(cur.count());
System.out.println(cur.getCursorId());
System.out.println(JSON.serialize(cur));
}
}
[/code]
2、完成CRUD操作，首先建立一个MongoDB4CRUDTest.java，基本测试代码如下：

[code]packagecom.hoo.test;
importjava.net.UnknownHostException;
importjava.util.ArrayList;
importjava.util.List;
importorg.bson.types.ObjectId;
importorg.junit.After;
importorg.junit.Before;
importorg.junit.Test;
importcom.mongodb.BasicDBObject;
importcom.mongodb.Bytes;
importcom.mongodb.DB;
importcom.mongodb.DBCollection;
importcom.mongodb.DBCursor;
importcom.mongodb.DBObject;
importcom.mongodb.Mongo;
importcom.mongodb.MongoException;
importcom.mongodb.QueryOperators;
importcom.mongodb.util.JSON;
/**
*<b>function:</b>实现MongoDB的CRUD操作
*@authorhoojo
*@createDate2011-6-2下午03:21:23
*@fileMongoDB4CRUDTest.java
*@packagecom.hoo.test
*@projectMongoDB
*@blog
'target='_blank'>http://blog.csdn.net/IBM_hoojo
*@emailhoojo_@126.com
*@version1.0
*/
publicclassMongoDB4CRUDTest{
privateMongomg=null;
privateDBdb;
privateDBCollectionusers;
@Before
publicvoidinit(){
try{
mg=newMongo();
//mg=newMongo("localhost",27017);
}catch(UnknownHostExceptione){
e.printStackTrace();
}catch(MongoExceptione){
e.printStackTrace();
}
//获取tempDB；如果默认没有创建，mongodb会自动创建
db=mg.getDB("temp");
//获取usersDBCollection；如果默认没有创建，mongodb会自动创建
users=db.getCollection("users");
}
@After
publicvoiddestory(){
if(mg!=null)
mg.close();
mg=null;
db=null;
users=null;
System.gc();
}
publicvoidprint(Objecto){
System.out.println(o);
}
}
[/code]
3、添加操作
在添加操作之前，我们需要写个查询方法，来查询所有的数据。代码如下：
[code]/**
*<b>function:</b>查询所有数据
*@authorhoojo
*@createDate2011-6-2下午03:22:40
*/
privatevoidqueryAll(){
print("查询users的所有数据：");
//db游标
DBCursorcur=users.find();
while(cur.hasNext()){
print(cur.next());
}
}
@Test
publicvoidadd(){
//先查询所有数据
queryAll();
print("count:"+users.count());
DBObjectuser=newBasicDBObject();
user.put("name","hoojo");
user.put("age",24);
//users.save(user)保存，getN()获取影响行数
//print(users.save(user).getN());
//扩展字段，随意添加字段，不影响现有数据
user.put("sex","男");
print(users.save(user).getN());
//添加多条数据，传递Array对象
print(users.insert(user,newBasicDBObject("name","tom")).getN());
//添加List集合
List<DBObject>list=newArrayList<DBObject>();
list.add(user);
DBObjectuser2=newBasicDBObject("name","lucy");
user.put("age",22);
list.add(user2);
//添加List集合
print(users.insert(list).getN());
//查询下数据，看看是否添加成功
print("count:"+users.count());
queryAll();
}
[/code]
4、删除数据
[code]@Test
publicvoidremove(){
queryAll();
print("删除id=4de73f7acd812d61b4626a77："+users.remove(newBasicDBObject("_id",newObjectId("4de73f7acd812d61b4626a77"))).getN());
print("removeage>=24:"+users.remove(newBasicDBObject("age",newBasicDBObject("$gte",24))).getN());
}
[/code]
5、修改数据
[code]@Test
publicvoidmodify(){
print("修改："+users.update(newBasicDBObject("_id",newObjectId("4dde25d06be7c53ffbd70906")),newBasicDBObject("age",99)).getN());
print("修改："+users.update(
newBasicDBObject("_id",newObjectId("4dde2b06feb038463ff09042")),
newBasicDBObject("age",121),
true,//如果数据库不存在，是否添加
false//多条修改
).getN());
print("修改："+users.update(
newBasicDBObject("name","haha"),
newBasicDBObject("name","dingding"),
true,//如果数据库不存在，是否添加
true//false只修改第一天，true如果有多条就不修改
).getN());
//当数据库不存在就不修改、不添加数据，当多条数据就不修改
//print("修改多条："+coll.updateMulti(newBasicDBObject("_id",newObjectId("4dde23616be7c19df07db42c")),newBasicDBObject("name","199")));
}
[/code]
6、查询数据
[code]@Test
publicvoidquery(){
//查询所有
//queryAll();
//查询id=4de73f7acd812d61b4626a77
print("findid=4de73f7acd812d61b4626a77:"+users.find(newBasicDBObject("_id",newObjectId("4de73f7acd812d61b4626a77"))).toArray());
//查询age=24
print("findage=24:"+users.find(newBasicDBObject("age",24)).toArray());
//查询age>=24
print("findage>=24:"+users.find(newBasicDBObject("age",newBasicDBObject("$gte",24))).toArray());
print("findage<=24:"+users.find(newBasicDBObject("age",newBasicDBObject("$lte",24))).toArray());
print("查询age!=25："+users.find(newBasicDBObject("age",newBasicDBObject("$ne",25))).toArray());
print("查询agein25/26/27："+users.find(newBasicDBObject("age",newBasicDBObject(QueryOperators.IN,newint[]{25,26,27}))).toArray());
print("查询agenotin25/26/27："+users.find(newBasicDBObject("age",newBasicDBObject(QueryOperators.NIN,newint[]{25,26,27}))).toArray());
print("查询ageexists排序："+users.find(newBasicDBObject("age",newBasicDBObject(QueryOperators.EXISTS,true))).toArray());
print("只查询age属性："+users.find(null,newBasicDBObject("age",true)).toArray());
print("只查属性："+users.find(null,newBasicDBObject("age",true),0,2).toArray());
print("只查属性："+users.find(null,newBasicDBObject("age",true),0,2,Bytes.QUERYOPTION_NOTIMEOUT).toArray());
//只查询一条数据，多条去第一条
print("findOne:"+users.findOne());
print("findOne:"+users.findOne(newBasicDBObject("age",26)));
print("findOne:"+users.findOne(newBasicDBObject("age",26),newBasicDBObject("name",true)));
//查询修改、删除
print("findAndRemove查询age=25的数据，并且删除:"+users.findAndRemove(newBasicDBObject("age",25)));
//查询age=26的数据，并且修改name的值为Abc
print("findAndModify:"+users.findAndModify(newBasicDBObject("age",26),newBasicDBObject("name","Abc")));
print("findAndModify:"+users.findAndModify(
newBasicDBObject("age",28),//查询age=28的数据
newBasicDBObject("name",true),//查询name属性
newBasicDBObject("age",true),//按照age排序
false,//是否删除，true表示删除
newBasicDBObject("name","Abc"),//修改的值，将name修改成Abc
true,
true));
queryAll();
}
[/code]
mongoDB不支持联合查询、子查询，这需要我们自己在程序中完成。将查询的结果集在Java查询中进行需要的过滤即可。
7、其他操作

[code]publicvoidtestOthers(){
DBObjectuser=newBasicDBObject();
user.put("name","hoojo");
user.put("age",24);
//JSON对象转换
print("serialize:"+JSON.serialize(user));
//反序列化
print("parse:"+JSON.parse("{\"name\":\"hoojo\",\"age\":24}"));
print("判断tempCollection是否存在:"+db.collectionExists("temp"));
//如果不存在就创建
if(!db.collectionExists("temp")){
DBObjectoptions=newBasicDBObject();
options.put("size",20);
options.put("capped",20);
options.put("max",20);
print(db.createCollection("account",options));
}
//设置db为只读
db.setReadOnly(true);
//只读不能写入数据
db.getCollection("test").save(user);
}
[/code]
好了，这里基本上就介绍这么多Java操作MongoDB的方法。其他的东西还需要你自己多多研究。上面操作MongoDB的方法都是一些常用的方法，比较简单。如果有什么问题，可以给我留言或是发Email:hoojo_@126.com