下面是我的代码
import com.mongodb.MongoClient;
import com.mongodb.client.*;
import org.bson.Document;
import java.util.ArrayList;
import java.util.List;
public class MongoMain {
static MongoClient mongoClient = null;
static MongoDatabase mdb = null;
static MongoCollection<Document> collection = null;
public static void main(String args[]){
try {
mongoClient = new MongoClient("localhost", 27017);
mdb = mongoClient.getDatabase("STAJDB");
collection = mdb.getCollection("users");
listAllDatabaseNames();
} catch (Exception e) {
e.printStackTrace();
} finally {
mongoClient.close();
}
}
public static void listAllDatabaseNames(){
MongoCursor<String> databases = mongoClient.listDatabaseNames().iterator();
while(databases.hasNext()) {
System.out.println(databases);
listAllCollections(databases.toString());
databases.next();
}
}
public static void listAllCollections(String databaseName){
MongoDatabase currentDb = mongoClient.getDatabase(databaseName);
MongoCursor<String> collections = currentDb.listCollectionNames().iterator();
while(collections.hasNext()){
System.out.println("\t" + collections);
listALLDocuments(collections.toString());
collections.next();
}
}
public static void listALLDocuments(String colName){
MongoCollection<Document> col = mdb.getCollection(colName);
List<Document> documents = col.find().into(new ArrayList<Document>());
for(Document doc : documents){
System.out.println("\t\t" + doc.toString());
}
}
}
让我们假设我有4个名为A，B和C的数据库。每个数据库都有1个集合，每个集合都有1个文档。我想这样列出他们。
A
a1
a2
B
b1
b2
C
c1
c2
数据库名称和文档名称按预期工作，但是当我尝试通过打印集合名称来执行此操作时，却遇到此异常。
com.mongodb.client.internal.MongoMappingCursor@610694f1
java.lang.IllegalArgumentException: state should be: databaseName does not contain '.'
at com.mongodb.assertions.Assertions.isTrueArgument(Assertions.java:99)
at com.mongodb.MongoNamespace.checkDatabaseNameValidity(MongoNamespace.java:61)
at com.mongodb.client.internal.MongoDatabaseImpl.<init>(MongoDatabaseImpl.java:68)
at com.mongodb.MongoClient.getDatabase(MongoClient.java:533)
at com.ibrahim.MongoMain.listAllCollections(MongoMain.java:47)
at com.ibrahim.MongoMain.listAllDatabaseNames(MongoMain.java:41)
at com.ibrahim.MongoMain.main(MongoMain.java:23)
Jul 13, 2018 11:51:35 AM com.mongodb.diagnostics.logging.JULLogger log
INFO: Closed connection [connectionId{localValue:2, serverValue:24}] to localhost:27017 because the pool has been closed.