Develop Reference

How to get the value if resultset matched with the entire row value?

Here I attached my code. When if stateVector contains the statename I need to check the that entire row only, not all the icd and dicd vector value. How I need to do that?
In my code its checking all vectors once the statename matched with any other or icdid it's showing it's available.
public class LCDEdits
{
#SuppressWarnings("unchecked")
public String validateICD_CPT(String cptCode, String stateName, String icdCode) throws Exception
{
/**** Variable Initialization ***/
String lcdRes = null;
StringBuffer lcdSql = null;
// String error = null;
java.sql.Connection con = null;
java.sql.PreparedStatement poStmt1 = null;
DBConfig db1 = null;
ResultSet rs = null;
JSONObject JObj = new JSONObject();
try
{
lcdSql = new StringBuffer(" SELECT cpt.hcpc_code, cpt.lcd_id, statepri.state_abbr, icd.icd10_id, ");
lcdSql.append(" dicd.icd10_id_dont FROM lcd_cpt cpt ");
lcdSql.append(" LEFT JOIN lcd_statepri statepri ON(cpt.lcd_id = statepri.lcd_id) ");
//lcdSql.append(" LEFT JOIN lcd_statesec statesec ON( cpt.lcd_id = statesec.lcd_id) ");
lcdSql.append(" LEFT JOIN lcd_icd_support icd ON( cpt.lcd_id = icd.lcd_id) ");
lcdSql.append(" LEFT JOIN lcd_icd_dont_support dicd ON( cpt.lcd_id = dicd.lcd_id) ");
lcdSql.append(" WHERE hcpc_code = ? ");
db1 = new DBConfig();
con = db1.openConn();
poStmt1 = con.prepareStatement(lcdSql.toString());
poStmt1.setString(1, cptCode);
rs = poStmt1.executeQuery();
Vector<String> stateVector = new Vector<String>();
Vector<String> icdVector = new Vector<String>();
Vector<String> dicdVector = new Vector<String>();
while(rs.next())
{
stateVector.add(rs.getString("state_abbr") );
// icdVector.add(rs.getString("icd10_id") );
// dicdVector.add(rs.getString("icd10_id_dont") );
//stateVector.add(rs.getString("sec_state_abbr") );
}
if(stateVector.contains(stateName))
{
if(icdVector.contains(icdCode))
{
// String lcd_icd = lcd_Id;
lcdRes = "CPT-Code is Available in LCD Database.";
// lcdRes1 = "As for the LCD-Code " +lcd_icd+ ", the CPT-Code " + cptCode + " is supported the Diagnosis " +icdCode+ " in the state of " +stateName+ ".";
}
else if(dicdVector.contains(icdCode))
{
lcdRes = "Medicare is not interest to pay Amount for this CPT-Code.";
// lcdRes1 = "As for the LCD-Code " +lcd_Id+ ", the CPT-Code " +cptCode+ " is not supported the Diagnosis " +icdCode+ " in the state of " +stateName+ ".";
}
else
{
lcdRes = "CPT-Code is not available in the LCD-Database.";
// lcdRes1 = "As for the LCD-Code " +lcd_Id+ ", the CPT-Code " +cptCode+ " is not applicable for the Diagnosis " +icdCode+ " in the state of " +stateName+ ".";
}
}
else
{
// String lcd_state = lcd_Id;
lcdRes = "State not matched with LCD-Code.";
// lcdRes1 = "As for the LCD-Code " +lcd_state+ ", the CPT-Code " +cptCode+ " is not applicable in the state of " +stateName+ ".";
}
JObj.put("status", "success");
JObj.put("res_msg", lcdRes);
// JObj.put("dis_msg", lcdRes1);
}
catch(Exception ex) {
ex.printStackTrace();
JObj.put("status", "failed");
}
finally {
rs.close();
poStmt1.close();
db1.closeConnection(con);
}
return JObj.toString();
}
}

First, separate the reading from the database and the processing of the data.
Vector stateVector = null;
try {
Reading data from database
} catch (the problems) {
And handle them
} finally {
close the connection
}
then check if you have some data:
if (stateVector != null {
// get the data you want, probably with a loop construct
}

java return data to java client

i have java client send to server (jetty-xmlrpc) query and receive data from server inside hashmap. sometime data is more big(e.g. 3645888 rows), when this data send to java client i have error ( java heap space ). how can i send data by 2 times for example ? or give me way to fix it
this is server function to get data and send it to client
public HashMap getFlickValues(String query,String query2){
System.out.println("Query is : "+query);
System.out.println("Query2 is: "+query2);
Connection c = null;
Connection c2 = null;
Statement st = null;
Statement st2 = null;
HashMap<String, Object[]> result = new HashMap<String, Object[]>();
ArrayList<Double> vaArrL = new ArrayList<Double>();
ArrayList<Double> vbArrL = new ArrayList<Double>();
ArrayList<Double> vcArrL = new ArrayList<Double>();
try {
Class.forName("org.postgresql.Driver");
String conString = "jdbc:postgresql://" + host + ":" + port + "/" + DBName +
"?user=" + user + "&pass=" + pass;
String conString1 = "jdbc:postgresql://" + host + ":" + port2 + "/" + DBName2 +
"?user=" + user + "&pass=" + pass;
//String conString1 = "jdbc:postgresql://127.0.0.1:5431/merkezdbram " +
// "?user=" + user + "&pass=" + pass;
/*c = DriverManager.getConnection(conString);
st = c.createStatement();
ResultSet rs = st.executeQuery(query);
while (rs.next()){
vaArrL.add(rs.getDouble("va"));
vbArrL.add(rs.getDouble("vb"));
vcArrL.add(rs.getDouble("vc"));
}*/
c = DriverManager.getConnection(conString);
//c.setAutoCommit(false);
c2 = DriverManager.getConnection(conString1);
//c2.setAutoCommit(false);
st = c.createStatement();
//st.setFetchSize(1000);
st2 = c2.createStatement();
//st2.setFetchSize(1000);
List<ResultSet> resultSets = new ArrayList<>();
resultSets.add(st.executeQuery(query));
resultSets.add(st2.executeQuery(query2));
ResultSets rs = new ResultSets(resultSets);
int count = 0;
int ResultSetSize = rs.getFetchSize();
System.out.println("ResultSetSize is "+ResultSetSize);
while (rs.next()){
//count++;
//if ( count == 2200000) { break;}
vaArrL.add(rs.getDoubleVa("va"));
vbArrL.add(rs.getDoubleVb("vb"));
vcArrL.add(rs.getDoubleVc("vc"));
}
int sz = vaArrL.size();
result.put("va", vaArrL.toArray(new Object[sz]));
result.put("vb", vbArrL.toArray(new Object[sz]));
result.put("vc", vcArrL.toArray(new Object[sz]));
//rs.close();
st.close();
c.close();
} catch ( Exception e ) {
System.out.println(e);
e.printStackTrace();
}
System.out.println("Flicker vaArrL.size = "+vaArrL.size());
return result;
}
and ResultSets class is :
class ResultSets {
private java.util.List<java.sql.ResultSet> resultSets;
private java.sql.ResultSet current;
public ResultSets(java.util.List<java.sql.ResultSet> resultSets) {
this.resultSets = new java.util.ArrayList<>(resultSets);
current = resultSets.remove(0);
}
public boolean next() throws SQLException {
if (current.next()) {
return true;
}else if (!resultSets.isEmpty()) {
current = resultSets.remove(0);
return next();
}
return false;
}
public Double getDoubleVa(String va) throws SQLException{
return current.getDouble("va");
}
public Double getDoubleVb(String vb) throws SQLException{
return current.getDouble("vb");
}
public Double getDoubleVc(String vc) throws SQLException{
return current.getDouble("vc");
}
}
i want way to return data to client without (java heap space) ?
i make -Xmx1024m for VM argument , but same problrm
i want solution in my code
thanks

How to generalize resultset queries?

at the moment I'm working on a script that reads several values from different tables of one database. Every time I start a request, I have to open a statement and create a new resultset which leads to horrible, repetative code. What would be a good way of generalizing this and how can this be done?
Some elements from my code. At the moment there's just one statement and the closing has to be inserted. One of the primary reasons I ask this question.
public static void main(String[] args) throws Exception
{
Connection c = null;
Statement stmt = null;
try
{
//set up database connection
Class.forName("org.sqlite.JDBC");
c = DriverManager.getConnection("jdbc:sqlite:/nfs/home/mals/p/pu2002/workspace/Database2");
c.setAutoCommit(false);
stmt = c.createStatement();
//end
//get task id to work with
String Task_id = null;
if(args.length != 0) //if an argument was passed, Task_id will be the first element of the array args (arguments)
{
Task_id = args[0];
}
else if(args.length == 0) //if no arguments were passed, the highest number in the column id from tasks_task will be selected and set as Task_id
{
ResultSet TTask_id = stmt.executeQuery("SELECT max(id) FROM tasks_task");
int t_id = TTask_id.getInt(1);
Task_id = String.valueOf(t_id);
TTask_id.close();
}
//end
//get solution IDs from taks_ids
ArrayList<Integer> List_solIDs = new ArrayList<Integer>(); //create an empty array list
ResultSet SSolution_task_id = stmt.executeQuery("SELECT id FROM solutions_solution WHERE task_id ="+Task_id + " AND final = 1;"); //Sqlite3-Ausdruck SELECT..., Task IDs verändern pro Aufgabe - "SELECT * FROM solutions_solution where task_id ="+Task_id +";"
while (SSolution_task_id.next()) //loops through all elements of SSolution_task_id
{
List_solIDs.add(SSolution_task_id.getInt("id")); //adds all elements of the resultset SSolution_task_id to the list List_solIDs
}
SSolution_task_id.close();
//end
//get logs according to content type
int count = List_solIDs.size();
String log_javaBuilder = null;
List<String> log_JunitChecker = new ArrayList<String>();
for (int i = 0; i < count; i++)
{
boolean sol_id_valid = false;
String solID = String.valueOf(List_solIDs.get(i));
try
{
ResultSet AAttestation_sol_id = stmt.executeQuery("SELECT * FROM attestation_attestation WHERE solution_id =" +solID+";");
int Returned = AAttestation_sol_id.getInt("final_grade_id");
}
catch(Exception e)
{
sol_id_valid = true;
}
if(sol_id_valid ==true)
{
try
{
ResultSet CCresult_javaBuilder = stmt.executeQuery("SELECT log FROM checker_checkerresult WHERE solution_id = " +solID+ " AND content_type_id = 22;"); //"SELECT id FROM checker_checkerresult where solution_id = " +List_solIDs.get(i)+ ";"
log_javaBuilder = CCresult_javaBuilder.getString("log");
CCresult_javaBuilder.close();
ResultSet CCresult_Junit_checker = stmt.executeQuery("SELECT log FROM checker_checkerresult WHERE solution_id = " +solID+ " AND content_type_id = 24;");
while (CCresult_Junit_checker.next())
{
log_JunitChecker.add(CCresult_Junit_checker.getString("log"));
}
CCresult_Junit_checker.close();
}
catch (Exception e)
{
log_JunitChecker.add(null);
}
//end
All types of potential improvements will be welcome.
P.S.: Tried googling.

Seems you want to look at using some ORM layer e.g. http://hibernate.org/orm/
What you're looking for is probably a higher-level layer which
abstracts you from the underlying lower-level JDBC type of coding.

Better than writing generic method by yourself it is always better to use some framework, There are many JPA implementations out there which solve not only this issue but also takes care of multiple persistence layer boiler plate code. Start JPA from Here. You can also use Spring JDBC template as well to solve problem mentioned above Spring JDBC Documentation.
Now, if you really don't want any framework dependency and finish this code quite fast, You can define your own JDBCTemplate class which takes query and parameter map and return ResultSet. This class can handle open connection, query execution and closing connection etc.

What if you try to use generics on methods? this is a quick example, just for illustration, you must improve all this :)
resource: official docs
public static <T> List<T> getSingleValueList(ResultSet rs, Class<T> clazz, String colName) throws Exception {
ArrayList<T> list = new ArrayList<T>();
while (rs.next()) {//loops through all elements of generic list
list.add((T) rs.getObject(colName)); //adds all elements of the resultset rs to the list
}
rs.close();
return list;
}
public static <T> T getSingleValue(ResultSet rs, Class<T> clazz, String colName) throws Exception {
try {
if (rs.next()) {//loops through all elements of generic list
return (T) rs.getObject(colName);
} else {
throw new Exception("no value found.");
}
} finally {
rs.close();
}
}
public static void main(String[] args) throws Exception {
Connection c = null;
Statement stmt = null;
try {
//set up database connection
Class.forName("org.sqlite.JDBC");
c = DriverManager.getConnection("jdbc:sqlite:/nfs/home/mals/p/pu2002/workspace/Database2");
c.setAutoCommit(false);
stmt = c.createStatement();
//end
//get task id to work with
String Task_id = null;
if (args.length != 0) //if an argument was passed, Task_id will be the first element of the array args (arguments)
{
Task_id = args[0];
} else if (args.length == 0) //if no arguments were passed, the highest number in the column id from tasks_task will be selected and set as Task_id
{
ResultSet TTask_id = stmt.executeQuery("SELECT max(id) FROM tasks_task");
int t_id = TTask_id.getInt(1);
Task_id = String.valueOf(t_id);
TTask_id.close();
}
//end
//get solution IDs from taks_ids
ResultSet SSolution_task_id = stmt.executeQuery("SELECT id FROM solutions_solution WHERE task_id =" + Task_id + " AND final = 1;"); //Sqlite3-Ausdruck SELECT..., Task IDs verändern pro Aufgabe - "SELECT * FROM solutions_solution where task_id ="+Task_id +";"
List<Integer> List_solIDs = getSingleValueList(SSolution_task_id, Integer.class, "id"); //create an empty array list
//end
//get logs according to content type
int count = List_solIDs.size();
String log_javaBuilder = null;
List<String> log_JunitChecker = new ArrayList<String>();
List<String> tmplog_JunitChecker;
for (int i = 0; i < count; i++) {
boolean sol_id_valid = false;
String solID = String.valueOf(List_solIDs.get(i));
try {
ResultSet AAttestation_sol_id = stmt.executeQuery("SELECT * FROM attestation_attestation WHERE solution_id =" + solID + ";");
Integer Returned = getSingleValue(AAttestation_sol_id, Integer.class, "final_grade_id");
} catch (Exception e) {
sol_id_valid = true;
}
if (sol_id_valid == true) {
try {
ResultSet CCresult_javaBuilder = stmt.executeQuery("SELECT log FROM checker_checkerresult WHERE solution_id = " + solID + " AND content_type_id = 22;"); //"SELECT id FROM checker_checkerresult where solution_id = " +List_solIDs.get(i)+ ";"
log_javaBuilder = getSingleValue(CCresult_javaBuilder, String.class, "log");
ResultSet CCresult_Junit_checker = stmt.executeQuery("SELECT log FROM checker_checkerresult WHERE solution_id = " + solID + " AND content_type_id = 24;");
tmplog_JunitChecker = getSingleValueList(CCresult_Junit_checker, String.class, "log");
log_JunitChecker.addAll(tmplog_JunitChecker);
} catch (Exception e) {
log_JunitChecker.add(null);
}
//end
}
}
} catch (Exception eeee) {
//handle it
}
}
I hope I gave you a light.
Anyway, frameworks in almost all cases help a lot.

How to create a list using PreparedStatement?

I have following codes:
-------class------------
private class SystemHealthAlert implements Work {
List<MonitorAlertInstance> systemHealthAlertList;
private String queryString;
// private java.util.Date startDate;
// private java.util.Date endDate;
#Override
public void execute(Connection connection) throws SQLException {
PreparedStatement ps = connection.prepareStatement(queryString);
int index = 1;
ResultSet rs = ps.executeQuery();
int columnCount = rs.getMetaData().getColumnCount();
while(rs.next())
{
//String[] row = new String[columnCount];
//results.set(index, element);
//for (int i=0; i <columnCount ; i++)
// {
// row[i] = rs.getString(i + 1);
// }
systemHealthAlertList.add(row);
}
rs.close();
ps.close();
}
}
---------Method-----------
public List<MonitorAlertInstance> getSystemHealthAlert(Long selectedSensorId) {
List<MonitorAlertInstance> systemHealthAlertList;
try {
// Add SELECT with a nested select to get the 1st row
String queryString = "select min(MONITOR_ALERT_INSTANCE_ID) as MONITOR_ALERT_INSTANCE_ID, description" +
" from ems.monitor_alert_instance " +
" where description in (select description from monitor_alert_instance" +
" where co_mod_asset_id = " + selectedSensorId +
" )" +
" group by description";
SystemHealthAlert work = new SystemHealthAlert();
// work.coModAssetId = coModAssetId;
work.queryString = queryString;
getSession().doWork(work);
systemHealthAlertList = work.systemHealthAlertList;
} catch (RuntimeException re) {
// log.error("getMostRecentObservationId() failed", re);
throw re;
}
//log.info("End");
return systemHealthAlertList;
}
My query returns three rows from DB. How can I return systemHealthAlertList from the class that will have all the three rows of the query.

In method execute, you should fill your List<MonitorAlertInstance> systemHealthAlertList with instances of MonitorAlertInstance. Create a new instance of MonitorAlertInstance inside the while loop where you retrieve the data:
//You don't need this line, remove it
//int columnCount = rs.getMetaData().getColumnCount();
while(rs.next()) {
//create a new instance of MonitorAlertInstance per ResultSet row
MonitorAlertInstance monitor = new MonitorAlertInstance();
//set the fields from the ResultSet in your MonitorAlertInstance fields
//since I don't know the fields of this class, I would use field1 and field2 as examples
monitor.setField1(rs.getInt(1));
monitor.setField2(rs.getString(2));
//and on...
systemHealthAlertList.add(monitor);
}
Apart from this problem, you should initialize your List<MonitorAlertInstance> systemHealthAlertList variable before use it:
systemHealthAlertList = new ArrayList<MonitorAlertInstance>();
while(rs.next()) {
//content from previous code...
}

Define a class/bean to hold the data from one given row. Loop through your rows, and create one instance of that class for each row you have. Add these instances to some List. Return the List of these 3 instances.

Java/SQL result-stack error

Here is a method that I am writing for a class. It is supposed to refresh a table with data obtained from quering a database. I get an error when trying to scan through the line newResult.next().
I tried debugging, but that doesn't show me anything. the code prints out the line "In while loop", so I know that the problem is the in the line right after it. I constantly get the error, "After start of result set". I tried looking at my code, but it doesn't look like I am calling that method anywhere else either. thanks.
public void refresh()
{
try
{
Statement statement = gtPort.getConnection().createStatement();
//this query is also not working, not really sure how it works.
String query = "SELECT CRN, Title, Instructor, Time, Day, Location, Letter"
+ "FROM Section S WHERE CRN NOT IN "
+ "(SELECT CRN FROM Registers R WHERE Username = \""
+ gtPort.userName + "\")";
System.out.println(query);
statement.executeQuery(query);
System.out.println("Statemetne execute ");
// String[] columns = {"Select", "CRN", "Title", "Instructor", "Time",
// "Days", "location", "Course Code*", "Section"*,"Mode of Grading*"};
ResultSet result = statement.getResultSet();
System.out.println("created result");
data = new Object[10][10];
System.out.println("created data");
Object[] values = new Object[10];
System.out.println("created values");
// values[0] = null;
if (result == null)
{
System.out.println("result is null");
}
String[] titles = new String[100];
//for (int i = 1; i< table.getColumnCount(); i++)
//model.removeRow(i);
//table.removeAll();
//table.repaint()
model.setRowCount(0);
table = new JTable(model);
model.setRowCount(35);
for (int i = 1; result.next(); i++)
{
values[1] = Boolean.FALSE;
for (int j = 2; j< 8; j++)
values[j] = result.getString(j);
titles[i] = result.getString(2);
model.insertRow(i, values);
}
String[] codes = new String[table.getColumnCount()];
System.out.println("count: " + titles.length);
for (int i = 1; I < titles.length; i++)
{
query = new String("SELECT C.Code FROM Code C WHERE C.Title = \""
+ titles[i] + "\"");
//this is a different query to check for titles.
statement.executeQuery(query);
System.out.println(query);
ResultSet newResult = statement.getResultSet();
// codes[i] = newResult.getString(1);
if (newResult == null)
{
System.out.println("it is null");
break;
}
//this is the loop where it breaks.
while(newResult.next());
{
System.out.println("in while loop");
//this line prints, so the next line must be the problem.
model.setValueAt(newResult.getString(1), i, 8);
}
System.out.println("nr: \t" +newResult.getString(1));
}
System.out.println("before table");
table = new JTable(model);
System.out.println("created table");
}
catch (Exception exe)
{
System.out.println("errored in course selection");
System.out.println(exe);
}
}

Write ResultSet rs = statement.executeQuery(query); instead. getResultSet() is called when you have got more then one result sets from executed statement.
Don't use constructor new String() for creating String. Simply write:
String new = "content";
You cannot predict how much your first query will return so don't create arrays with stated size but use better ArrayList:
Code:
//creation
List<Object> values = new ArrayList<Object>();
List<String> titles = new ArrayList<String>();
//usage - adding
values.add(someObject);
//usage - getting
for (String title : titles)
//or
titles.get(byIndex);