java操作mongodb示例分享
package mymaven;
import java.net.unknownhostexception;
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.mongo;
import com.mongodb.mongoexception;
public class test {
public static void main(string[] args) throws unknownhostexception, mongoexception {
mongo mongo = new mongo("172.27.9.104", 27017); // 连接数据库
db db = mongo.getdb("mytestdb"); // 数据库
set<string> cols = db.getcollectionnames(); // 获取数据库中所有的集合（类似于获取关系数据库中的表）
// 打印出数据库中的集合，这里应当为null
for (string s : cols) {
system.out.println(s);
}
dbcollection collection = db.getcollection("mytestcoll"); // 创建一个集合
collection.drop(); // 删除集合，插入数据时自动重建
basicdbobject obj = new basicdbobject(); // 初始化一个基本db对象，插入数据库的就是db对象
obj.put("from", "blog.ithomer.net"); // 放入几个键值对
obj.put("to", "forum.ithomer.net");
obj.put("subject", "ithomer.net");
collection.insert(obj); // 插入对象
dbobject dbobj = collection.findone(); // 查看一条记录，findone()=find().limit(1);
system.out.println(dbobj); // 打印出刚才插入的数据
// 插入10条{ranking:i}的数据
for (int i = 0; i < 10; i++) {
collection.insert(new basicdbobject().append("ranking", i));
}
system.out.println("count: " + collection.getcount()); // 打印集合中的数据总数
dbcursor cursor = collection.find(); // 然后我们使用这个游标来遍历集合
while (cursor.hasnext()) {
system.out.println(cursor.next());
}
// 简单的条件查询，查询ranking为1的记录
basicdbobject query = new basicdbobject();
query.put("ranking", 1);
cursor = collection.find(query);
system.out.println("collection find({\"ranking\":1}):");
while (cursor.hasnext()) {
system.out.println(cursor.next());
}
// 复杂的条件查询，查询ranking大于等于5小于9的记录
query = new basicdbobject();
query.put("ranking", new basicdbobject("$gte", 5).append("$lt", 9));
cursor = collection.find(query);
system.out.println("collection find({\"ranking\":[5-9)}):");
while (cursor.hasnext()) {
system.out.println(cursor.next());
}
// mongo.dropdatabase("mytestdb"); // 最后删除我们的测试数据库
}
}
运行结果：
mytestcoll
system.indexes
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10107"} , "from" : "blog.ithomer.net" , "to" : "forum.ithomer.net" , "subject" : "ithomer.net"}
count: 11
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10107"} , "from" : "blog.ithomer.net" , "to" : "forum.ithomer.net" , "subject" : "ithomer.net"}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10108"} , "ranking" : 0}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10109"} , "ranking" : 1}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010a"} , "ranking" : 2}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010b"} , "ranking" : 3}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010c"} , "ranking" : 4}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010d"} , "ranking" : 5}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010e"} , "ranking" : 6}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010f"} , "ranking" : 7}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10110"} , "ranking" : 8}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10111"} , "ranking" : 9}
collection find({"ranking":1}):
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10109"} , "ranking" : 1}
collection find({"ranking":[5-9)}):
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010d"} , "ranking" : 5}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010e"} , "ranking" : 6}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd1010f"} , "ranking" : 7}
{ "_id" : { "$oid" : "52c62ed8e4b0f4de3dd10110"} , "ranking" : 8}
mongodb数组示例：
@suppresswarnings("unchecked")
public static void loadmediatags(list<mediaentity> mediaentitylist) {
mediaentitylist.clear();
try {
mongo mongo = new mongo(cosinecluster.gmongo_host, cosinecluster.gmongo_port);
db db = mongo.getdb(cosinecluster.gmongo_db);
dbcollection collection = db.getcollection(cosinecluster.gmongo_coll_media);
dbcursor cursor = collection.find();
int index = 0;
long starttime = system.currenttimemillis();
while(cursor.hasnext()){
basicdbobject obj = (basicdbobject) cursor.next();
long id = obj.getlong("_id");
arraylist<string> taglist = (arraylist<string>) obj.get("tag"); // tag
arraylist<string> keywordlist = (arraylist<string>)obj.get("keyword"); // keyword
arraylist<integer> copyrightlist = (arraylist<integer>)obj.get("copyright"); // copyright
mediaentity mediaentity = new mediaentity();
mediaentity.setid(id);
// tag
for(int j=0; j<taglist.size(); j++) {
mediaentity.addtag(taglist.get(j));
int tagid = gettagint(taglist.get(j));
mediaentity.addtag(tagid);
}
// actors
arraylist<dbobject> actorsobjlist = (arraylist<dbobject>)obj.get("actors"); // actors
for(int j=0; j<actorsobjlist.size(); j++) {
mediaentity.addactor((string) actorsobjlist.get(j).get("name"));
int actorid = getactorint((string)actorsobjlist.get(j).get("name"));
mediaentity.addactor(actorid);
}
// director
arraylist<dbobject> directorobjlist = (arraylist<dbobject>)obj.get("director"); // director
for(int j=0; j<directorobjlist.size(); j++) {
mediaentity.adddirector((string) directorobjlist.get(j).get("name"));
int directorid = getdirectorint((string) directorobjlist.get(j).get("name"));
mediaentity.adddirector(directorid);
}
// keyword
for(int j=0; j<keywordlist.size(); j++) {
mediaentity.addkeyword(keywordlist.get(j));
int keywordid = getkeywordint(keywordlist.get(j));
mediaentity.addkeyword(keywordid);
}
// copyright
for(int j=0; j<copyrightlist.size(); j++) {
mediaentity.addcopyright(copyrightlist.get(j));
}
mediaentitylist.add(mediaentity);
index++;
if(index > 100) {
break;
}
system.out.println(index + " --- mediaentity : " + mediaentity.tostring());
}
long costtime = system.currenttimemillis() - starttime;
system.out.println("load data costtime = " + index + "; costtime = " + costtime/1000f);
} catch (exception e) {
e.printstacktrace();
}
}
public static int gettagint(string tag) {
int tagintid = -1;
try {
mongoclient mongo = new mongoclient(cosinecluster.gmongo_host, cosinecluster.gmongo_port);
db db = mongo.getdb(cosinecluster.gmongo_db);
dbcollection tagmapcollection = db.getcollection("recommend_tag_map");
dbcursor cursor = tagmapcollection.find(new basicdbobject("name", tag));
if(cursor == null || cursor.toarray().size() <= 0) { // 处理小于2或n的映射关键字，下同
return tagintid;
}
dbobject obj = cursor.toarray().get(0);
string name = tag;
tagintid = (integer) obj.get("id");
int num = (integer) obj.get("num");
mongo.close();
} catch (unknownhostexception e) {
e.printstacktrace();
}
return tagintid;
}
public static int getactorint(string actor) {
int actorintid = -1;
try {
mongoclient mongo = new mongoclient(cosinecluster.gmongo_host, cosinecluster.gmongo_port);
db db = mongo.getdb(cosinecluster.gmongo_db);
dbcollection tagmapcollection = db.getcollection("recommend_actor_map");
dbcursor cursor = tagmapcollection.find(new basicdbobject("name", actor));
if(cursor == null || cursor.toarray().size() <= 0) {
return actorintid;
}
dbobject obj = cursor.toarray().get(0);
string name = actor;
actorintid = (integer) obj.get("id");
int num = (integer) obj.get("num");
mongo.close();
} catch (unknownhostexception e) {
e.printstacktrace();
}
return actorintid;
}