DbUtils for java

package com.nilpower.dao.impl; import java.sql.ResultSet; import java.sql.SQLException; import java.util.List; import java.util.Map; import java.util.Properties; import org.apache.commons.dbutils.QueryRunner; import org.apache.commons.dbutils.ResultSetHandler; import org.apache.commons.dbutils.handlers.BeanHandler; import org.apache.commons.dbutils.handlers.BeanListHandler; import org.apache.commons.dbutils.handlers.MapListHandler; import org.apache.log4j.Logger; import com.mysql.jdbc.JDBC4Connection; import com.mysql.jdbc.jdbc2.optional.MysqlDataSource; import com.nilpower.dao.Dao; /** * @author Z.ting 2011-8-10 下午08:05:06 */ public class DaoImpl implements Dao { private MysqlDataSource dataSource = new MysqlDataSource(); private QueryRunner qryRun = null; private Logger logger = Logger.getLogger(getClass()); private java.sql.DatabaseMetaData dbmb; public DaoImpl() { dataSource.setUrl("jdbc:mysql://localhost:3306/dbutils"); dataSource.setUser("root"); dataSource.setPassword("kelvin"); qryRun = new QueryRunner(dataSource); dbmb = getDatabaseMetaData(); } private java.sql.DatabaseMetaData getDatabaseMetaData() { Properties info = new Properties(); info.setProperty("user", "root"); info.setProperty("password", "kelvin"); java.sql.DatabaseMetaData metaData = null; try { metaData = new JDBC4Connection("localhost", 3306, info, "dbutils", null).getMetaData(); } catch (SQLException e) { e.printStackTrace(); } return metaData; } public <T extends Object> List<T> findAll(Class<T> clazz) { ResultSetHandler<List<T>> rsh = new BeanListHandler<T>(clazz); List<T> result = null; try { result = qryRun.query("select * from " + clazz.getSimpleName(), rsh); logger.debug("SQL: select * from " + clazz.getSimpleName()); } catch (SQLException e) { logger.error("Can not this query table " + clazz.getSimpleName(), e); } return result; } public <T> T findById(Class<T> clazz, int id) { ResultSetHandler<T> rsh = new BeanHandler<T>(clazz); T result = null; try { ResultSet rs = dbmb.getPrimaryKeys(null, null, clazz.getSimpleName()); String primary_key = null; while (rs.next()) { primary_key = rs.getString("Column_name"); } if (!"".equals(primary_key) || null != primary_key) { result = qryRun.query("select * from " + clazz.getSimpleName() + " where " + primary_key + "=?", rsh, new Object[] { id }); logger.debug("SQL: select * from " + clazz.getSimpleName() + " where " + primary_key + "=" + id); } else { logger.error("This table " + clazz.getSimpleName() + " has not primary key"); throw new SQLException("This table has not primary key"); } } catch (SQLException e) { logger.error("Can not this query table " + clazz.getSimpleName(), e); } return result; } public List<Map<String, Object>> executeQuery(String sql, Object... args) { MapListHandler rsh = new MapListHandler(); List<Map<String, Object>> result = null; try { result = qryRun.query(sql, rsh, args); } catch (SQLException e) { e.printStackTrace(); } return result; } public long insert(String sql, Object... args) { return executeUpdate(sql, args); } public long update(String sql, Object... args) { return executeUpdate(sql, args); } public void delete(String sql, Object... args) { executeUpdate(sql, args); } public long executeUpdate(String sql, Object... args) { long id = 0; try { id = qryRun.update(sql, args); } catch (SQLException e) { logger.error("This table can not changed !", e); } return id; } public int[] batchUpdate(String sql, Object[][] objs) { int[] ids = null; try { ids = qryRun.batch(sql, objs); } catch (SQLException e) { e.printStackTrace(); } return ids; } }