JDBC公共操作类，jdbc, import j

JDBC公共操作类，jdbc, import j

    import java.sql.Connection;      import java.sql.DriverManager;      import java.sql.ResultSet;      import java.sql.SQLException;      import java.sql.Statement;      public class DBUtil {          public static final String DRIVER = "com.mysql.jdbc.Driver";          public static final String URL = "jdbc:mysql://localhost:3306/db";          public static final String USERNAME = "root";          public static final String PASSWORD = "root";          /**          * 通过静态代码块 注册数据库驱动          */          static {              try {                  Class.forName(DRIVER);              } catch (ClassNotFoundException e) {                  e.printStackTrace();              }          }          /**          * 获得Connection          *           * @return          */          public static Connection getConnection() {              Connection conn = null;              try {                  conn = DriverManager.getConnection(URL, USERNAME, PASSWORD);              } catch (SQLException e) {                  e.printStackTrace();              }              return conn;          }          /**          * 获得Statement          *           * @return          */          public static Statement getStatement() {              Statement st = null;              try {                  st = getConnection().createStatement();              } catch (SQLException e) {                  e.printStackTrace();              }              return st;          }          /**          * 关闭ResultSet          *           * @param rs          */          public static void closeResultSet(ResultSet rs) {              if (rs != null) {                  try {                      rs.close();                  } catch (SQLException e) {                      e.printStackTrace();                  }              }          }          /**          * 关闭Statement          *           * @param st          */          public static void closeStatement(Statement st) {              if (st != null) {                  try {                      st.close();                  } catch (SQLException e) {                      e.printStackTrace();                  }              }          }          /**          * 关闭Connection          *           * @param conn          */          public static void closeConnection(Connection conn) {              if (conn != null) {                  try {                      conn.close();                  } catch (SQLException e) {                      e.printStackTrace();                  }              }          }          /**          * 关闭全部          *           * @param rs          * @param sta          * @param conn          */          public static void closeAll(ResultSet rs, Statement sta, Connection conn) {              closeResultSet(rs);              closeStatement(sta);              closeConnection(conn);          }      }