How to find whether a ResultSet is empty or not in Java? [duplicate]

This question already has answers here: Java ResultSet how to check if there are any results (23 answers) Closed 9 years ago. 开发者_运维问答

How can I find that the ResultSet, that I have got by querying a database, is empty or not?

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Immediately after your execute statement you can have an if statement. For example

ResultSet rs = statement.execute();
if (!rs.next()){
//ResultSet is empty
}

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Definitely this gives good solution,

ResultSet rs = stmt.execute("SQL QUERY");
// With the above statement you will not have a null ResultSet 'rs'.
// In case, if any exception occurs then next line of code won't execute.
// So, no problem if I won't check rs as null.

if (rs.next()) {
    do {
      // Logic to retrieve the data from the resultset.
      // eg: rs.getString("abc");
    } while(rs.next());
} else {
    // No data
}

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Do this using rs.next():

while (rs.next())
{
    ...
}

If the result set is empty, the code inside the loop won't execute.

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If you use rs.next() you will move the cursor, than you should to move first() why don't check using first() directly?

    public void fetchData(ResultSet res, JTable table) throws SQLException{     
    ResultSetMetaData metaData = res.getMetaData();
    int fieldsCount = metaData.getColumnCount();
    for (int i = 1; i <= fieldsCount; i++)
        ((DefaultTableModel) table.getModel()).addColumn(metaData.getColumnLabel(i));
    if (!res.first())
        JOptionPane.showMessageDialog(rootPane, "no data!");
    else
        do {
            Vector<Object> v = new Vector<Object>();
            for (int i = 1; i <= fieldsCount; i++)              
                v.addElement(res.getObject(i));         
            ((DefaultTableModel) table.getModel()).addRow(v);
        } while (res.next());
        res.close();
}

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if (rs == null || !rs.first()) {
    //empty
} else {
    //not empty
}

Note that after this method call, if the resultset is not empty, it is at the beginning.

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Calculates the size of the java.sql.ResultSet:

int size = 0;
if (rs != null) {
    rs.beforeFirst();
    rs.last();
    size = rs.getRow();
}

(Source)