问生成密码保护pdf。如何为每个用户获得唯一的密码？

EN

import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;

import net.sf.jasperreports.engine.JRDefaultScriptlet;
import net.sf.jasperreports.engine.JRScriptletException;
import net.sf.jasperreports.engine.fill.JRFillParameter;

public class GetBirthdayScriptlet extends JRDefaultScriptlet {

    private Connection conn;

    private Connection getConnection() throws JRScriptletException {
        if (conn == null) {
            if (getParameterValue(JRFillParameter.REPORT_CONNECTION) != null) {
                conn = (Connection) (getParameterValue(JRFillParameter.REPORT_CONNECTION));
            } else {
                throw new RuntimeException("No db-connection configured in the report!");
            }
        }
        return conn;
    }

    public String getBirthday(String email) throws JRScriptletException, SQLException {
        ResultSet result = null;
        String resultString = null;
        CallableStatement stmt = getConnection().prepareCall("select birthday from birthday_table where email = " + email);
        stmt.executeUpdate();
        result = stmt.getResultSet();
        if(result.next()){
            result.getString(1);
        }
        return resultString;
    }
}

$P{>>scriptlet-name<<_SCRIPTLET}.getBirthday("email@example.com")