java学习笔记：Statement详解

java学习笔记：Statement详解

Statement详解 ---- 1.Statement的含义：向数据库发送sql语句，获得执行结果。 2.方法解释 (1)Statement.executeQuery(String sql);//用于向数据库发送select语句，返回ResultSet结果集对象 代码示例： String sql = "select * from user;"; ResultSet rs = stmt.executeQuery(sql); (2)Statement.executeUpdate(String sql);//用于向数据库发送insert、update、delete语句，返回int类型参数，代表影响记录的行数 (3)Statement.execute(String sql);//不区分语句，返回boolean类型参数 true表示sql是select语句，然后可以用stmt.getResultSet()返回ResultSet false表示sql是 非select语句，然后可以用stmt.getUpdateCount()返回int 代码示例： @Test public void testStatementQuery(){ Connection conn = null; Statement stmt = null; ResultSet rs = null; try{ conn = JDBCUtils.getConnection(); stmt = conn.createStatement(); String sql = "select * from user"; //String sql = "update user set password=123 where username=lisi;"; boolean flag = stmt.execute(sql); if(flag){ rs = stmt.getResultSet(); while(rs.next()){ int id = rs.getInt("id"); String username = rs.getString("username"); String password = rs.getString("password"); System.out.println(id + "::" + username + "::" + password); } }else{ int sum = stmt.getUpdateCount(); System.out.println(sum); } }catch(Exception e){e.printStackTrace();} finally{JDBCUtils.release(conn, stmt, rs);} }//end of method testStatementQuery