学生管理系统的添加

1:后台方法的实现

//班级的添加的实现
    public int gradeAdd(Connection con,Grade grade)throws Exception
    {
        String sql = "insert into t_grade values(null,?,?)";
        PreparedStatement pstmt = con.prepareStatement(sql);
        pstmt.setString(1, grade.getGradeName());
        pstmt.setString(2, grade.getGradeDesc());
        return pstmt.executeUpdate();
    }

    //班级的修改的实现
    public int gradeModify(Connection con,Grade grade)throws Exception{
        String sql = "update t_grade set gradeName=?,gradeDesc=? where id=?";
        PreparedStatement pstmt = con.prepareStatement(sql);
        pstmt.setString(1, grade.getGradeDesc());
        pstmt.setString(2, grade.getGradeDesc());
        pstmt.setInt(3, grade.getId());

        return pstmt.executeUpdate();
    }

2：在新建一个servlet类，建好这个类之后就再web.xml配置：

  <servlet>
      <servlet-name>gradeSaveServlet</servlet-name>
      <servlet-class>com.fxr.web.GradeSaveServlet</servlet-class>
  </servlet>

  <servlet-mapping>
      <servlet-name>gradeSaveServlet</servlet-name>
      <url-pattern>/gradeSave</url-pattern>
  </servlet-mapping>
  

3：编写前台的界面：

1. 首先引入JQuery的easyui-dialog对话框

easyui-validatebox表单验证功能

对话框的代码：

<!-- 添加对话框 -->
    <div id="dlg" class="easyui-dialog" style="width:400px;height:280px;padding:10px 20px" 

         closed = "true" buttons = "#dlg-buttons">

         <form id="fm" method="post">
           <table>

           <tr>
                    <td>班级名称：</td>
                    <td><input type="text" name="gradeName" id="gradeName" class="easyui-validatebox" required="true"/></td>

           </tr>

           <tr>
                    <td valign="top">班级描述：</td>
                    <td><textarea rows="7" cols="30" name="gradeDesc" id="gradeDesc"></textarea></td>
           </tr>

           </table>

         </form>

    </div>

    <div id="dlg-buttons">
        <a href="javascript:saveGrade()" class="easyui-linkbutton" iconCls="icon-ok">保存</a>
        <a href="javascript:closeGradeDialog()" class="easyui-linkbutton" iconCls="icon-cancel">关闭</a>
    </div>
    

用Javascript做点击添加按钮的操作弹出对话框：

<a href="javascript:openGradeAddDialog()" class="easyui-linkbutton" iconCls="icon-add" plain="true">添加</a>

function openGradeAddDialog(){
        $("#dlg").dialog("open").dialog("setTitle","添加班级信息");
        url="gradeSave";//提交给那个servlet处理
    }

同样的方式修改的对话框：

<a href="javascript:openGradeModifyDialog()" class="easyui-linkbutton" iconCls="icon-edit" plain="true">修改</a>

function openGradeModifyDialog(){
        var selectedRows=$("#dg").datagrid(‘getSelections‘);
        if(selectedRows.length!=1){
            $.messager.alert("系统提示","请选择一条要编辑的数据！");
            return;
        }
        var row=selectedRows[0];
        $("#dlg").dialog("open").dialog("setTitle","编辑班级信息");
        $("#fm").form("load",row);
        url="gradeSave?id="+row.id;
    }

保存的按钮操作：

<div id="dlg-buttons">
        <a href="javascript:saveGrade()" class="easyui-linkbutton" iconCls="icon-ok">保存</a>
        <a href="javascript:closeGradeDialog()" class="easyui-linkbutton" iconCls="icon-cancel">关闭</a>
    </div>

保存的javascript方法的实现：

function saveGrade(){
        $("#fm").form("submit",{
            url:url,
            onSubmit:function(){
                return $(this).form("validate");
            },
            success:function(result){
                if(result.errorMsg){
                    $.messager.alert("系统提示",result.errorMsg);
                    return;
                }else{
                    $.messager.alert("系统提示","保存成功");
                    resetValue();
                    $("#dlg").dialog("close");
                    $("#dg").datagrid("reload");
                }
            }
        });
    }

function resetValue(){
$("#gradeName").val("");
$("#gradeDesc").val("");
}

后台servlet的代码的实现：

package com.fxr.web;

import java.io.IOException;
import java.sql.Connection;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.sf.json.JSONObject;

import com.fxr.dao.GradeDao;
import com.fxr.model.Grade;
import com.fxr.util.DbUtil;
import com.fxr.util.ResponseUtil;
import com.fxr.util.StringUtil;

public class GradeSaveServlet extends HttpServlet{

    DbUtil dbUtil=new DbUtil();
    GradeDao gradeDao=new GradeDao();

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        this.doPost(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        request.setCharacterEncoding("utf-8");
        String gradeName=request.getParameter("gradeName");
        String gradeDesc=request.getParameter("gradeDesc");
        String id=request.getParameter("id");
        Grade grade=new Grade(gradeName,gradeDesc);
        if(StringUtil.isNotEmpty(id)){
            grade.setId(Integer.parseInt(id));
        }
        Connection con=null;
        try{
            con=dbUtil.getCon();
            int saveNums=0;
            JSONObject result=new JSONObject();
            if(StringUtil.isNotEmpty(id)){
                saveNums=gradeDao.gradeModify(con, grade);
            }else{
                saveNums=gradeDao.gradeAdd(con, grade);
            }
            if(saveNums>0){
                result.put("success", "true");
            }else{
                result.put("success", "true");
                result.put("errorMsg", "保存失败");
            }
            ResponseUtil.write(response, result);
        }catch(Exception e){
            e.printStackTrace();
        }finally{
            try {
                dbUtil.closeCon(con);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

}