我使用以下代码连接到3个不同的数据库并对它们运行查询。但是当我从第二个查询中获取结果时，它给出了一个错误，说明resultSet已经关闭。
import java.io.*;
import java.sql.*;
public class DB {
String sourceQueryResults ="no results", cbosQueryResults = "no results", tiQueryResults = "no results";
public DB() {}
//below is the function called in Main to run connection
public void dbConnect(String sourceConnectString,
String db_userid, String db_password, String sourceTablename, String sourceSchemaName,
String sourceCondition, String cbosConnectString, String cbosTableName,
String cbosSchemaName, String cbosCondition, String tiConnectString,
String tiTableName, String tiSchemaName, String tiCondition, String fileName)
{
try
{
Class.forName("com.ibm.db2.jcc.DB2Driver");
System.out.println("Loaded!");
/*
* Below creates a connection to the databases
*/
//below attempts to connect to the source DB
Connection sourceConn = DriverManager.getConnection(
sourceConnectString, db_userid, db_password);
System.out.println("Source DB Connected at: " + sourceConnectString);
System.out.println("Schema: " + sourceSchemaName);
System.out.println("Table: " + sourceTablename);
//below attempts to connect to the CBOS DB
Connection cbosConn = DriverManager.getConnection(cbosConnectString,
db_userid, db_password);
System.out.println("CBOS DB Connected at: " + cbosConnectString);
System.out.println("Schema: " + cbosSchemaName);
System.out.println("Table: " + cbosTableName);
//below attempts to connect to the CBOS DB
Connection tiConn = DriverManager.getConnection(cbosConnectString,
db_userid, db_password);
System.out.println("TI Db Connected!");
System.out.println("TI DB Connected at: " + tiConnectString);
System.out.println("Schema: " + tiSchemaName);
System.out.println("Table: " + tiTableName);
/*
* Below set all of the statement and results for all of the data locations
*/
Statement sourceStmt = sourceConn.createStatement();
ResultSet sourceRs;
Statement cbosStmt = cbosConn.createStatement();
ResultSet cbosRs;
Statement tiStmt = tiConn.createStatement();
ResultSet tiRs;
/*
* Below establishes for all data locations (source/cbos/ti) whether
* conditions will be used or not
*/
//below for source
if(sourceCondition == null) {
System.out.println("Is there a sourceCondition?");
sourceQueryResults = ("SELECT COUNT(*) as testvalue FROM " + sourceSchemaName + "." +
sourceTablename + "WHERE "
+ sourceCondition);
//sets the results to needed query
sourceRs = sourceStmt.executeQuery("SELECT COUNT(*) as testvalue FROM " + sourceSchemaName + "." +
sourceTablename + "WHERE "
+ sourceCondition);
}else {
System.out.println("there is no source condition");
//sets the variable used later in printing of results
sourceQueryResults = ("SELECT COUNT(*) as testvalue FROM " + sourceSchemaName + "." +
sourceTablename);
//this means there is no conditions to select on
//sourceRs = sourceStmt.executeQuery("SELECT COUNT(*) FROM " +
// sourceSchemaName + "." + sourceTablename + ";");
System.out.println(sourceQueryResults);
sourceRs = sourceStmt.executeQuery( "SELECT count(*) FROM " + sourceSchemaName + "." +
sourceTablename);
System.out.println("Got access to the table and selected!!!");
}
//below for CBOS
if(cbosCondition == null) {
cbosQueryResults = ("SELECT COUNT(*) as testvalue FROM " + cbosSchemaName + "." +
cbosTableName + "WHERE "
+ cbosCondition);
//sets the results to needed query
cbosRs = cbosStmt.executeQuery("SELECT COUNT(*) as testvalue FROM " + cbosSchemaName + "." +
cbosTableName + "WHERE "
+ cbosCondition);
}else {
//sets the variable used later in printing of results
cbosQueryResults = ("SELECT COUNT(*) as testvalue FROM " + cbosSchemaName + "." +
cbosTableName);
//this means there is no conditions to select on
System.out.println(cbosQueryResults);
cbosRs = cbosStmt.executeQuery("SELECT COUNT(*) as testvalue FROM " + cbosSchemaName +
"." + cbosTableName);
}
//below for TI
if(tiCondition == null) {
tiQueryResults = ("SELECT COUNT(*) as testvalue FROM " + tiSchemaName + "." +
tiTableName + "WHERE "
+ tiCondition);
//sets the results to needed query
tiRs = cbosStmt.executeQuery("SELECT COUNT(*) as testvalue FROM " + tiSchemaName + "." +
tiTableName + "WHERE "
+ tiCondition);
}else {
//sets the variable used later in printing of results
tiQueryResults = ("SELECT COUNT(*) as testvalue FROM " + tiSchemaName + "." +
tiTableName);
System.out.println(tiQueryResults);
//this means there is no conditions to select on
tiRs = cbosStmt.executeQuery("SELECT COUNT(*) FROM " + tiSchemaName + "." +
tiTableName);
}
/*
* Below gets the value of the users desktop
*/
String userHomeFolder = System.getProperty("user.home") + "/Desktop";
//below creates a new file with given fileName
File resultsFile = new File(userHomeFolder, fileName + ".txt");
/*
* Below creates a string for saving results from each data location query
*/
System.out.println(sourceRs);
String sTestValue = "stest";
String cTestValue = "ctest";
String tTestValue = "ttest";
/*
* Below attempts to write out the gathered results to the created file
*/
try (BufferedWriter out = new BufferedWriter(new FileWriter(resultsFile))){
//below writes a header to the SOURCE part query result
out.write("********* Below is the query results from SOURCE table ********" + "\n");
System.out.println("sourceQueryResults = :" + sourceQueryResults);
out.write(sourceQueryResults + "\n");
//below iterates through the returned results
while (sourceRs.next() ) {
//this writes all of the results to the test file
sTestValue = sourceRs.getString(1);
System.out.println("writing Source count is: " + sTestValue);
out.write(sTestValue + "\n");
}
sourceRs.close();
//below writes a header to the CBOS part query result
out.write("********* Below is the query results from CBOS table ********" + "/n");
out.write(cbosQueryResults + "/n");
//below iterates through the returned results
while(cbosRs.next()) {
//this writes all of the CBOS results to test file
cTestValue = cbosRs.getString(1);
System.out.println("writing cbos count is: " + cTestValue);
out.write(cTestValue + "\n");
}
` cbosRs.close();
//below writes a header to TI part of the query result
out.write("********* Below is the query results from TI table ********" + "\n");
out.write(tiQueryResults + "\n");
//below iterates through the returned results
while(tiRs.next()) {
//this writes all of the CBOS results to test file
tTestValue = tiRs.getString(1);
System.out.println("writing TI count is: " + tTestValue);
out.write(tTestValue + "\n");
}
tiRs.close();
out.close();
}
}
//below catches any errors for any of the above work
catch (Exception e)
{
e.printStackTrace();
System.err.println(e.getMessage());
}
}
}
错误发生在该行：
while(cbosRs.next()) {
答案 0 :(得分：1)
首先，您似乎只连接到2个数据库。
Connection tiConn = DriverManager.getConnection(cbosConnectString,
db_userid, db_password);
在这里，您将再次连接到cbosConnectString，而不是tiConnectString。
其次，您的代码中有一些任意符号：
` cbosRs.close();
最后，尝试关闭finally块中的每个resultSet。