[java] Iterating over ResultSet and adding its value in an ArrayList

If I've understood your problem correctly, there are two possible problems here:

  • resultset is null - I assume that this can't be the case as if it was you'd get an exception in your while loop and nothing would be output.
  • The second problem is that resultset.getString(i++) will get columns 1,2,3 and so on from each subsequent row.

I think that the second point is probably your problem here.

Lets say you only had 1 row returned, as follows:

Col 1, Col 2, Col 3 
A    ,     B,     C

Your code as it stands would only get A - it wouldn't get the rest of the columns.

I suggest you change your code as follows:

ResultSet resultset = ...;
ArrayList<String> arrayList = new ArrayList<String>(); 
while (resultset.next()) {                      
    int i = 1;
    while(i <= numberOfColumns) {
        arrayList.add(resultset.getString(i++));
    }
    System.out.println(resultset.getString("Col 1"));
    System.out.println(resultset.getString("Col 2"));
    System.out.println(resultset.getString("Col 3"));                    
    System.out.println(resultset.getString("Col n"));
}

Edit:

To get the number of columns:

ResultSetMetaData metadata = resultset.getMetaData();
int numberOfColumns = metadata.getColumnCount();

Examples related to java

Under what circumstances can I call findViewById with an Options Menu / Action Bar item? How much should a function trust another function How to implement a simple scenario the OO way Two constructors How do I get some variable from another class in Java? this in equals method How to split a string in two and store it in a field How to do perspective fixing? String index out of range: 4 My eclipse won't open, i download the bundle pack it keeps saying error log

Examples related to jdbc

Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver' Hibernate Error executing DDL via JDBC Statement Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment] MySQL JDBC Driver 5.1.33 - Time Zone Issue Spring-Boot: How do I set JDBC pool properties like maximum number of connections? Where can I download mysql jdbc jar from? Print the data in ResultSet along with column names How to set up datasource with Spring for HikariCP? java.lang.ClassNotFoundException: sun.jdbc.odbc.JdbcOdbcDriver Exception occurring. Why? java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost:3306/dbname

Examples related to resultset

Mapping a JDBC ResultSet to an object JDBC ResultSet: I need a getDateTime, but there is only getDate and getTimeStamp Python, how to check if a result set is empty? Iterating over ResultSet and adding its value in an ArrayList Get Number of Rows returned by ResultSet in Java What does "if (rs.next())" mean? How to get row count using ResultSet in Java? Trying to get the average of a count resultset Efficient way to Handle ResultSet in Java Most efficient conversion of ResultSet to JSON?

Examples related to loops

How to increment a letter N times per iteration and store in an array? Angular 2 Cannot find control with unspecified name attribute on formArrays What is the difference between i = i + 1 and i += 1 in a 'for' loop? Prime numbers between 1 to 100 in C Programming Language Python Loop: List Index Out of Range JavaScript: Difference between .forEach() and .map() Why does using from __future__ import print_function breaks Python2-style print? Creating an array from a text file in Bash Iterate through dictionary values? C# Wait until condition is true