Java JDBC Reds Connection queryForList(String sql, Object... args)

Declaration

public static List<Map<String, Object>> queryForList(String sql, Object... args) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class Main {
    public static String URL;
    public static String USER_NAME;
    public static String PASSWORD;

    /**//  ww  w.  ja v  a 2s.co  m
     * Query a single record
     *
     * @param sql
     * @param args
     * @return List<Map<String,Object>>
     */
    public static List<Map<String, Object>> queryForList(String sql, Object... args) {
        List<Map<String, Object>> result = new ArrayList<Map<String, Object>>();
        Connection con = null;
        ResultSet rs = null;
        PreparedStatement ps = null;
        try {
            con = getconnnection();
            ps = con.prepareStatement(sql);
            if (args != null) {
                for (int i = 0; i < args.length; i++) {
                    ps.setObject((i + 1), args[i]);
                }
            }
            rs = ps.executeQuery();
            ResultSetMetaData rsmd = rs.getMetaData();
            int columnCount = rsmd.getColumnCount();
            while (rs.next()) {
                Map<String, Object> map = new HashMap<String, Object>();
                for (int i = 1; i <= columnCount; i++) {
                    map.put(rsmd.getColumnLabel(i), rs.getObject(i));
                }
                result.add(map);
            }
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            close(rs, ps, con);
        }
        return result;
    }

    /**
     * Query a single record
     *
     * @param sql
     * @param args
     * @return List<T>
     */
    public static <T> List<T> queryForList(String sql, Class<T> clz, Object... args) {
        List<T> result = new ArrayList<T>();
        Connection con = null;
        PreparedStatement ps = null;
        ResultSet rs = null;
        try {
            con = getconnnection();
            ps = con.prepareStatement(sql);
            if (args != null) {
                for (int i = 0; i < args.length; i++) {
                    ps.setObject((i + 1), args[i]);
                }
            }
            rs = ps.executeQuery();
            ResultSetMetaData rsmd = rs.getMetaData();
            int columnCount = rsmd.getColumnCount();
            while (rs.next()) {
                T obj = clz.newInstance();
                for (int i = 1; i <= columnCount; i++) {
                    String columnName = rsmd.getColumnName(i);
                    String methodName = "set" + columnName.substring(0, 1).toUpperCase()
                            + columnName.substring(1, columnName.length());
                    Method method[] = clz.getMethods();
                    for (Method meth : method) {
                        if (methodName.equals(meth.getName())) {
                            meth.invoke(obj, rs.getObject(i));
                        }
                    }
                }
                result.add(obj);
            }
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        } finally {
            close(rs, ps, con);
        }
        return result;
    }

    /**
     * Get connection
     *
     * @return
     */
    public static Connection getconnnection() {
        Connection con = null;
        try {
            con = DriverManager.getConnection(URL, USER_NAME, PASSWORD);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return con;
    }

    /**
     * Close connection
     *
     * @param rs
     * @param st
     * @param con
     */
    public static void close(ResultSet rs, Statement st, Connection con) {
        try {
            try {
                if (rs != null) {
                    rs.close();
                }
            } finally {
                try {
                    if (st != null) {
                        st.close();
                    }
                } finally {
                    if (con != null) {
                        con.close();
                    }
                }
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    /**
     * Close connection
     *
     * @param rs
     */
    public static void close(ResultSet rs) {
        Statement st = null;
        Connection con = null;
        try {
            try {
                if (rs != null) {
                    st = rs.getStatement();
                    rs.close();
                }
            } finally {
                try {
                    if (st != null) {
                        con = st.getConnection();
                        st.close();
                    }
                } finally {
                    if (con != null) {
                        con.close();
                    }
                }
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }

    /**
     * Close connection
     *
     * @param st
     * @param con
     */
    public static void close(Statement st, Connection con) {
        try {
            try {
                if (st != null) {
                    st.close();
                }
            } finally {
                if (con != null) {
                    con.close();
                }
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

Related

1. createRedshiftTable(String redshiftURL, Properties loginProperties, String tableName, List fields)
2. getRow(String username, String password, String url, String driver, String query, String[] params)
3. getUserFace(String sUserName)
4. getUserFromHost(String host)
5. query(String sql, Object... args)