Java知识点总结（JDBC-封装JDBC）

@(Java知识点总结)[Java, JDBC]

封装JDBC

1. src目录下新建一个db.PRoPErties文件，用于封装数据库连接信息

1. 把获取数据库连接对象和关闭连接的操作封装到 DBUtil 这个类中

import java.io.IOException; import java.SQL.Connection; import java.sql.DriverManager; import java.sql.Preparedstatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.statement; import java.util.Properties;   public class DBUtil {   static Properties pros; //读取和处理资源文件的信息      static{ // 只需要加载一次，所以写成静态代码块。执行本类时，加载     pros = new Properties();     try {      pros.load(Thread.currentThread().getContextClassLoader()          .getResourceAsStream("db.properties"));     } catch (IOException e) {      e.printStackTrace();     }   }     public static Connection getConn(){     Connection conn = null;     try {      Class. forName(pros.getProperty("MySQLDriver"));      conn = DriverManager.getConnection(pros.getProperty("mysqlUrl"),          pros.getProperty( "mysqlUser"), pros.getProperty("mysqlPassword"));     } catch (ClassNotFoundException | SQLException e) {      e.printStackTrace();     }     return conn;   }      // 不建议把conn写为静态的全局变量，然后在方法中关闭   public static void close(Connection conn){     try {      conn.close();     } catch (SQLException e) {      e.printStackTrace();     }   }      public static void close(Statement stmt) {     try {      stmt.close();     } catch (SQLException e) {      e.printStackTrace();     }   }      public static void close(PreparedStatement pstmt) {     if (pstmt != null) {      try {        pstmt.close();      } catch (SQLException e) {        e.printStackTrace();      }     }   }      public void close(ResultSet rs) {     try {      rs.close();     } catch (SQLException e) {      e.printStackTrace();     }   }      public static void commIT(Connection conn) {     if (conn != null) {      try {        conn.COMmit();      } catch (SQLException e) {        e.printStackTrace();      }     }   }      public static void rollback(Connection conn) {     if (conn != null) {      try {        conn.rollback();      } catch (SQLException e) {        e.printStackTrace();      }     }   }      public static void setAutoCommit(Connection conn, boolean autoCommit) {     if (conn != null) {      try {        conn.setAutoCommit(autoCommit);      } catch (SQLException e) {        e.printStackTrace();      }     }   }         //连接测试   public static void main(String[] args) {     if (DBUtil.getConn()!=null) {      System.out.println("连接成功！");           }   } }