如何从Java使用$query、$hint或$explain
我正在使用MongoDB 3.4 我的方法是:-如何从Java使用$query、$hint或$explain,java,mongodb,mongodb-query,Java,Mongodb,Mongodb Query,我正在使用MongoDB 3.4 我的方法是:- MongoDatabase db = mongo.getDatabase(mongoDBLogs); MongoIterable<String> allCollections = db.listCollectionNames(); str==FROM COLLECTION MongoCollection<Document> table = db.getCollection(str); MongoCursor<Docu
MongoDatabase db = mongo.getDatabase(mongoDBLogs);
MongoIterable<String> allCollections = db.listCollectionNames();
str==FROM COLLECTION
MongoCollection<Document> table = db.getCollection(str);
MongoCursor<Document> cursor = table.find(queryForLogs).iterator();
MongoDatabase db=mongo.getDatabase(mongodbogs);
MongoIterable allCollections=db.listCollectionNames();
str==来自集合
MongoCollection table=db.getCollection(str);
MongoCursor=table.find(queryForLogs.iterator();
问题是在旧版本中,我可以使用
DB db = mongo.getDB(mongoDBLogs);
Set<String> colls = db.getCollectionNames();
for (String s : colls) {
DBCollection table = db.getCollection(s);
cursor = table.find().explain(); <<<<---- I have this explain method
AND ALSO I have
cursor = table.find().hint(indexKeys);<<<<---- I have this hint method
}
DB-DB=mongo.getDB(mongodbogs);
Set colls=db.getCollectionNames();
for(字符串s:colls){
DBCollection table=db.getCollection;
cursor=table.find().explain();将$hint
或$explain
之类的内容发送到实际使用方法的Java驱动程序。例如:
MongoCursor<Document> iterator = collection.find()
.modifiers(new Document("$explain",1)).iterator();
while (iterator.hasNext()) {
System.out.println(iterator.next().toJson());
}
MongoCursor迭代器=collection.find()
.modifiers(新文档(“$explain”,1)).iterator();
while(iterator.hasNext()){
System.out.println(iterator.next().toJson());
}
这将打印explain stats输出
任何类型都可以作为参数提供。
有效列表在核心文档中
一般来说,$query
不是您实际从修饰符列表中使用的东西,因为您实际上是使用.find()
的任何参数来构造它。但是所有其他修饰符在这里都是有效的
MongoCursor<Document> cursor = table.find(queryForLogs).hint(Some value); <---This is type FindIterable<Document>
public BasicDBObject generateQueryForSessionIDLogs(String service_name, String node_name, Date gtDate, Date lteDate, String session_id,List<String> logLevel, String errorMsg){
BasicDBObject andQuery = new BasicDBObject();
List<BasicDBObject> obj = new ArrayList<BasicDBObject>();
//Use session to search. If session is unknown, start and end date must be provided
if(!session_id.isEmpty() && session_id != null){
String[] sessionarray = session_id.split(",");
if(sessionarray.length == 1){
Long val = Long.valueOf(sessionarray[0].trim()).longValue();
obj.add(new BasicDBObject("s", val));
} else{
ArrayList<Long> vals = new ArrayList<Long>();
for(String strn : sessionarray){
vals.add(Long.valueOf(strn.trim()).longValue());
}
obj.add(new BasicDBObject("s", new BasicDBObject("$in", vals )));
}
}else{
if((gtDate != null) && (lteDate != null)){
obj.add(new BasicDBObject("d", new BasicDBObject("$gt", gtDate).append("$lte", lteDate)));
}
}
if(!node_name.isEmpty()){
obj.add(new BasicDBObject("i", node_name));
}
if(!service_name.isEmpty()){
obj.add(new BasicDBObject("n", service_name ));
}
if(!errorMsg.isEmpty()) {
obj.add(new BasicDBObject("m", Pattern.compile(errorMsg)));
}
if(!logLevel.isEmpty()){
// obj.add(new BasicDBObject("r", new BasicDBObject("$in", logLevel )));
obj.add(new BasicDBObject("r", logLevel.get(0) ));
}
if (obj.size() > 1){ //append 'AND' if there is >1 conditions
andQuery.put("$and", obj);
}
BasicDBObject andQuery2 = new BasicDBObject();
andQuery2.put("$query", andQuery);
List<BasicDBObject> obj2 = new ArrayList<BasicDBObject>();
obj2.add(new BasicDBObject("i",1));
andQuery2.put("$hint", obj2);
andQuery2.put("$explain", 1);
logger.debug("Query String for Logs: " + andQuery2);
return andQuery;
}
MongoCursor<Document> iterator = collection.find()
.modifiers(new Document("$explain",1)).iterator();
while (iterator.hasNext()) {
System.out.println(iterator.next().toJson());
}