[java获得数据库信息常用API(DatabaseMetaData)示例]

/** * MongoDBTest * MongoDB更新数据使用示例 */ package com.labci.mongodb.test; import java.net.UnknownHostException; import java.util.Iterator; import com.mongodb.BasicDBObject; import com.mongodb.DB; import com.mongodb.DBCollection; import com.mongodb.DBCursor; import com.mongodb.DBObject; import com.mongodb.Mongo; import com.mongodb.MongoException; /** * * @author Bill Tu(tujiyue/iwtxokhtd) * May 22, 2011[3:10:56 PM] * */ public class MongoDBUpdateDataTest { private static final String HOST = "192.168.1.86"; private static final int PORT = 27017; private static final String USER = "iwtxokhtd"; private static final String PASSWORD = "123456"; private static final String DB_NAME = "test"; private static final String COLLECTION = "insert_test"; private static Mongo conn=null; private static DB myDB=null; private static DBCollection myCollection=null; static{ try { conn=new Mongo(HOST,PORT);//建立数据库连接 myDB=conn.getDB(DB_NAME);//使用test数据库 boolean loginSuccess=myDB.authenticate(USER, PASSWORD.toCharArray());//用户验证 if(loginSuccess){ myCollection=myDB.getCollection(COLLECTION); } } catch (UnknownHostException e) { e.printStackTrace(); } catch (MongoException e) { e.printStackTrace(); } } /** * 更新“表”数据 * @param collection */ private static void updateData(DBCollection collection){ DBObject updateCondition=new BasicDBObject(); //where name='fox' updateCondition.put("name", "fox"); DBObject updatedValue=new BasicDBObject(); updatedValue.put("headers", 3); updatedValue.put("legs", 4); DBObject updateSetValue=new BasicDBObject("$set",updatedValue); /** * update insert_test set headers=3 and legs=4 where name='fox' * updateCondition:更新条件 * updateSetValue:设置的新值 */ collection.update(updateCondition, updateSetValue); DBObject queryCondition=new BasicDBObject(); //where name='sam',此条件在更新前不是成立的 queryCondition.put("name", "sam"); DBObject setValue=new BasicDBObject(); setValue.put("headers", 1); setValue.put("legs", 1); DBObject upsertValue=new BasicDBObject("$set",setValue); /** * 后面两个参数含义分别是： * 若所更新的数据没有，则插入 * ，同时更新多个符合条件的文档(collection) */ collection.update(queryCondition, upsertValue, true, true); //set headers=headers+2 DBObject incValue=new BasicDBObject("headers",2); //set legs=4 DBObject legsValue=new BasicDBObject("legs",4); DBObject allCondition=new BasicDBObject(); allCondition.put("$inc", incValue); allCondition.put("$set", legsValue); collection.update(queryCondition, allCondition); } /** * 返回查询结果集 * @param collection * @return */ private static DBCursor queryData(DBCollection collection){ DBCursor queriedData=collection.find(); return queriedData; } /** * 打印结果数据 * @param description　结果数据相关描述 * @param recordResult　结果集 */ private static void printData(String description,DBCursor recordResult){ System.out.println(description); for(Iterator iter=recordResult.iterator();iter.hasNext();){ System.out.println(iter.next()); } } /** * @param args */ public static void main(String[] args) { printData("查看一下更新前的数据：",queryData(myCollection)); //更新数据 updateData(myCollection); printData("查看一下更新后的数据：",queryData(myCollection)); } }

运行结果：

查看一下更新前的数据： { "_id" : { "$oid" : "4dda4342b2d5a428449b7ce4"} , "name" : "fox" , "headers" : 3 , "legs" : 4} { "_id" : { "$oid" : "4dda4342b2d5a428449b7ce5"} , "name" : "tiger" , "headers" : 1 , "legs" : 3} { "_id" : { "$oid" : "4dda4840cfce8015e1824188"} , "headers" : 1 , "legs" : 1 , "name" : "sam"} { "_id" : { "$oid" : "4dda4342b2d5a428449b7ce2"} , "age" : "26" , "gender" : "m" , "headers" : 2 , "info" : { "height" : 16.3 , "weight" : 22} , "legs" : 4 , "userName" : "iwtxokhtd"} 查看一下更新后的数据： { "_id" : { "$oid" : "4dda4342b2d5a428449b7ce4"} , "name" : "fox" , "headers" : 3 , "legs" : 4} { "_id" : { "$oid" : "4dda4342b2d5a428449b7ce5"} , "name" : "tiger" , "headers" : 1 , "legs" : 3} { "_id" : { "$oid" : "4dda4840cfce8015e1824188"} , "headers" : 3 , "legs" : 4 , "name" : "sam"} { "_id" : { "$oid" : "4dda4342b2d5a428449b7ce2"} , "age" : "26" , "gender" : "m" , "headers" : 2 , "info" : { "height" : 16.3 , "weight" : 22} , "legs" : 4 , "userName" : "iwtxokhtd"}[/** * MongoDBTest * MongoDB插入和删除数据示例 */package com.labci.mongodb.test;import java.net.UnknownHostException;import java.util.ArrayList;import java.util