关于jsp访问mysql数据库的一些问题

index.jsp
<body>
    <form action="check.jsp" method="post">
        用户名<input type="text"  name="uname"><br/>
        密码<input type="password" name="upwd"><br/>
        <input type="submit"   value="登录"><br/>
    </form>
</body>

check.jsp
// 导入驱动,加载具体驱动类
        Class.forName("com.mysql.cj.jdbc.Driver");
        // 与数据库建立连接
        connection = DriverManager.getConnection(URL, USERNAME, PSW);
        // 发送sql,执行增、删、改
        stmt = connection.createStatement();
        String name=request.getParameter("uname");
        String pwd=request.getParameter("upwd");

        //错误写法1://String sql = "select count(*) from user where name=' "+name+" '  and  pwd=' "+pwd+" ' "; 

        String sql = "select count(*) from user where uname=' "+name+" '  and  upwd=' "+pwd+" ' ";
        //  =左边的uname是数据库中定义的字段名,右边的name是上面的String name获取的用户输入的值

        //错误写法2://String sql = "select name,pwd from user where name='name'  and  pwd='pwd' ";

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转载自blog.51cto.com/13592218/2464614