eclipse配置Servlet连接Mysql要注意的几个地方

用Servlet即把jdbc那套放到继承于HttpServlet的派生类之内，那段代码很简单

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setCharacterEncoding("Unicode");
        PrintWriter out=response.getWriter();
        String name=request.getParameter("username");
        String passwd=request.getParameter("passwd");
      try {
        Class.forName("com.mysql.jdbc.Driver");
    //    Class.forName("com.mysql.cj.jdbc.Driver");
        Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/stu", "root", "root");
        //Statement stmt=conn.createStatement();
        //ResultSet rs=stmt.executeQuery(sql);  //查询
        java.sql.PreparedStatement pstmt=conn.prepareStatement("select * from tb_user where name=? and password=?");
        pstmt.setString(1, name);
        pstmt.setString(2, passwd);
        //System.out.println();
        ResultSet rs=pstmt.executeQuery();
        rs.beforeFirst();
        if(rs.next())
        {
            out.println(rs.getString(1)+":"+rs.getString(2));
        }
        else{
            out.println("不存在该用户!");
        }
        rs.close();
        conn.close();
    } catch (ClassNotFoundException | SQLException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    }

  但注意要把jdbc放到tomcat目录中的lib中，不然报的那种错误，确实有点让人看不懂

还有编码的格式需要注意一下，有时候Mysql数据表中的编码，会与界面的编码格式不一致，比如我这是Unicode的

    response.setCharacterEncoding("Unicode");  

把Web.xml的配置文件也放上吧

  <servlet>
    <servlet-name>Login</servlet-name>
    <servlet-class>com.LoginServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>Login</servlet-name>
    <url-pattern>/ServerCoding1/aaa</url-pattern>
  </servlet-mapping>

调用类似

<a href="aaa">跳转<a/>

或

   <form action="ServerCoding1/aaa" method="post">

   <input type="submit" value="跳转">
     </form>