Java和MongoDB之Hello World

1.新建Project

新建Java Project,并把mongo-java-driver驱动加入到项目bulid path中,如果你使用的是maven增加依赖。


       < dependency >
          
< groupId > org.mongodb </ groupId >
          
< artifactId > mongo-java-driver </ artifactId >
          
< version > 2.10.1 </ version >
      
</ dependency >

2.连接上MongoDB

// >2.10版本
MongoClient mongo  =   new  MongoClient(  " localhost "  ,  27017  );
// 老版本  
Mongo mongo  =   new  Mongo( " localhost " 27017 );

如果需要验证,需要输入用户名和密码


    MongoClient mongoClient  =   new  MongoClient();
    DB db 
=  mongoClient.getDB( " database name " );
    
boolean  auth  =  db.authenticate( " username " " password " .toCharArray());
3.MongoDB数据库

得到MongoDB中的数据库,如果数据库名不存在,MongoDB会自动创建


DB db  =  mongo.getDB( " database name " );
显示所有的数据库
    List < String >  dbs  =  mongo.getDatabaseNames();
    
for (String db : dbs){
        System.out.println(db);
    }
4.MongoDB Collection(MongoDB表)

得到数据库中的表

    DB db  =  mongo.getDB( " testdb " );
    DBCollection table 
=  db.getCollection( " user " );
显示数据库中的所有表
    DB db  =  mongo.getDB( " testdb " );
    Set
< String >  tables  =  db.getCollectionNames();
 
    
for (String coll : tables){
        System.out.println(coll);
    }
5.插入、查找、更新、删除操作

插入数据,向Collection(表)中插入一个Document

    DBCollection table  =  db.getCollection( " user " );
    BasicDBObject document 
=   new  BasicDBObject();
    document.put(
" name " " qiyadeng " );
    document.put(
" age " 30 );
    document.put(
" createdDate " new  Date());
    table.insert(document);
更新Document中的name="qiyadeng.com"
    DBCollection table  =  db.getCollection( " user " );
     BasicDBObject query 
=   new  BasicDBObject();
    query.put(
" name " " qiyadeng " );
    BasicDBObject newDocument 
=   new  BasicDBObject();
    newDocument.put(
" name " " qiyadeng.com " );
    BasicDBObject updateObj 
=   new  BasicDBObject();
    updateObj.put(
" $set " , newDocument);
 
    table.update(query, updateObj);
从Collection中查找name="qiyadeng.com"的Document
    DBCollection table  =  db.getCollection( " user " );
 
    BasicDBObject searchQuery 
=   new  BasicDBObject();
    searchQuery.put(
" name " " qiyadeng.com " );
 
    DBCursor cursor 
=  table.find(searchQuery);
 
    
while  (cursor.hasNext()) {
        System.out.println(cursor.next());
    }
删除name="qiyadeng"的Document
    DBCollection table  =  db.getCollection( " user " );
 
    BasicDBObject searchQuery 
=   new  BasicDBObject();
    searchQuery.put(
" name " " qiyadeng.com " );
 
    table.remove(searchQuery);
6.完整的例子
package  com.qiyadeng.mongodb;
import  java.util.Date;
import  com.mongodb.BasicDBObject;
import  com.mongodb.DB;
import  com.mongodb.DBCollection;
import  com.mongodb.DBCursor;
import  com.mongodb.MongoClient;
public   class  MongoDBSample {
    
public   static   void  main(String[] args)  throws  Exception{
             
            
/** ** Connect to MongoDB *** */
            
// 2.10.0后,使用MongoClient
            MongoClient mongo  =   new  MongoClient( " localhost " 27017 );
         
            
/** ** Get database *** */
            
//  if database doesn't exists, MongoDB will create it for you
            DB db  =  mongo.getDB( " testdb " );
         
            
/** ** Get collection / table from 'testdb' *** */
            
//  if collection doesn't exists, MongoDB will create it for you
            DBCollection table  =  db.getCollection( " user " );
         
            
/** ** Insert *** */
            
//  create a document to store key and value
            BasicDBObject document  =   new  BasicDBObject();
            document.put(
" name " " qiyadeng " );
            document.put(
" age " 30 );
            document.put(
" createdDate " new  Date());
            table.insert(document);
         
            
/** ** Find and display *** */
            BasicDBObject searchQuery 
=   new  BasicDBObject();
            searchQuery.put(
" name " " qiyadeng " );
         
            DBCursor cursor 
=  table.find(searchQuery);
         
            
while  (cursor.hasNext()) {
                System.out.println(cursor.next());
            }
         
            
/** ** Update *** */
            
//  search document where name="qiyadeng" and update it with new values
            BasicDBObject query  =   new  BasicDBObject();
            query.put(
" name " " qiyadeng " );
         
            BasicDBObject newDocument 
=   new  BasicDBObject();
            newDocument.put(
" name " " qiyadeng.com " );
         
            BasicDBObject updateObj 
=   new  BasicDBObject();
            updateObj.put(
" $set " , newDocument);
         
            table.update(query, updateObj);
         
            
/** ** Find and display *** */
            BasicDBObject searchQuery2 
                
=   new  BasicDBObject().append( " name " " qiyadeng.com " );
         
            DBCursor cursor2 
=  table.find(searchQuery2);
         
            
while  (cursor2.hasNext()) {
                System.out.println(cursor2.next());
            }
    }
}

输出

" _id "  : {  " $oid "  :  " 51444c88874c79654063356b " } ,  " name "  :  " qiyadeng "  ,  " age "  :  30  ,  " createdDate "  : {  " $date "  :  " 2013-03-16T10:42:16.555Z " }}
" _id "  : {  " $oid "  :  " 51444c88874c79654063356b " } ,  " age "  :  30  ,  " createdDate "  : {  " $date "  :  " 2013-03-16T10:42:16.555Z " } ,  " name "  :  " qiyadeng.com " }
使用mongo验证创建的数据库testdb,collection user是否存在。

 

 

 

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