JDBC 经典操作

 总结下JDBC经典操作！

 1、JDBC往数据库插入一行：

	
       private static final String USER_INSERT = "insert into user (id, email, password, name) values(null, ?, ?, ?) " ;
	public void saveUser(User user){
		Connection conn = null ;
		PreparedStatement stmt = null ;
		try {
			conn = dateSource.getConnection(); //数据库连接
			stmt = conn.prepareStatement(USER_INSERT) ; //创建语句
			stmt.setString(1, user.getEmail()) ; //绑定参数
			stmt.setString(2, user.getPassword()) ;
			stmt.setString(3, user.getName()) ;
			
			stmt.execute() ;	//执行语句
		} catch (Exception e) {
			e.printStackTrace() ;
		}finally{
			/* 关闭资源 */
			try {
				if(stmt != null){
					stmt.close() ;
				}
				if(conn != null){
					conn.close() ;
				}
			} catch (Exception e) {
				e.printStackTrace() ;
			}
		}
	}

 2、JDBC往数据库更新一行：

	private static final String USER_UPDATE = "update user set email=?, password = ?, name=? where id=? " ;
	
	public void updateUser(User user){
		Connection conn = null ;
		PreparedStatement stmt = null ;
		try {
			conn = dateSource.getConnection(); //数据库连接
			stmt = conn.prepareStatement(USER_UPDATE) ; //创建语句
			stmt.setString(1, user.getEmail()) ; //绑定参数
			stmt.setString(2, user.getPassword()) ;
			stmt.setString(3, user.getName()) ;
			stmt.setInt(4, user.getID()) ;
			
			stmt.execute() ;	//执行语句
		} catch (Exception e) {
			e.printStackTrace() ;
		}finally{
			/* 关闭资源 */
			try {
				if(stmt != null){
					stmt.close() ;
				}
				if(conn != null){
					conn.close() ;
				}
			} catch (Exception e) {
				e.printStackTrace() ;
			}
		}
	}

3、JDBC从数据库中查询一行：

	private static final String USER_QUERY = "select id,email,password,name from user where id=? " ;
	
	public User getUserByID(Integer id){
		Connection conn = null ;
		PreparedStatement stmt = null ;
		ResultSet rs = null ;
		
		try {
			conn = dateSource.getConnection(); //数据库连接
			stmt = conn.prepareStatement(USER_QUERY) ; //创建语句
			stmt.setInt(1, id) ; //绑定参数
			rs = stmt.executeQuery() ;	//执行语句
			if(rs.next()){
				User user = new User() ;
				user.setID(rs.getInt("id")) ;
				user.setEmail(rs.getString("email")) ;
				user.setPassword(rs.getString("password")) ;
				user.setName(rs.getString("name")) ;
			}
			return user ;
		} catch (Exception e) {
			e.printStackTrace() ;
		}finally{
			/* 关闭资源 */
			try {
				if(rs != null){
					rs.close() ;
				}
				if(stmt != null){
					stmt.close() ;
				}
				if(conn != null){
					conn.close() ;
				}
			} catch (Exception e) {
				e.printStackTrace() ;
			}
		}
	}