EasyUI CRUD应用Java改造版本

EasyUI的CRUD应用采用的是php实现后台功能，将其改造为java版本实现数据表格的增删改功能。

EasyUI的教程及代码https://www.jeasyui.com/tutorial/app/crud.php

源代码结构：

1、建立数据库表，将users.sql导入mysql即可

2、修改index.html，将index.html中url的get_user.php替换为自己写的jsp代码

<table id="dg" title="My Users" class="easyui-datagrid" style="width:700px;height:250px"
            url="get_users.php"
            toolbar="#toolbar" pagination="true"
            rownumbers="true" fitColumns="true" singleSelect="true">

3、get_user.jsp，其中page和rows是翻页的参数，offset是用于分页查询使用的参数，需要返回总的记录数和数据库数据，采用json数据返回

<%@ page import="org.json.*" %>
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.ResultSet" %>
<%@ page import="java.sql.ResultSetMetaData" %>
<%@ page import="java.sql.Statement" %>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%
     //获取页数、显示记录参数
      int page1=Integer.parseInt(request.getParameter("page"));
      int rows1=Integer.parseInt(request.getParameter("rows"));
      int offset=(page1-1)*rows1;
      int total=0;

      String DB_driver="com.mysql.jdbc.Driver";
      String u="jdbc:mysql://localhost/test?user=root&password=root&useUnicode=true&characterEncoding=GBK";

     Class.forName(DB_driver);
        java.sql.Connection con = java.sql.DriverManager.getConnection(u);
     java.sql.Statement stmt =con.createStatement(); 

        String sql="select count(*)  total from users";
        java.sql.ResultSet rs = stmt.executeQuery(sql);
    if(rs.next())
        total=rs.getInt("total");
    JSONArray array = new JSONArray();
    JSONObject jsonObj2 = new JSONObject();

     sql="select * from users limit "+offset+","+rows1;
         rs = stmt.executeQuery(sql);
        ResultSetMetaData metaData = rs.getMetaData();
    int columnCount = metaData.getColumnCount(); 

        while (rs.next()) {
             JSONObject jsonObj = new JSONObject();
            for(int i=1;i<columnCount+1;i++)    {
                String columnName =metaData.getColumnLabel(i);
                String value = rs.getString(columnName);
                jsonObj.put(columnName, value); 

            }
              array.put(jsonObj); 

        }

    jsonObj2.put("total",total);
    jsonObj2.put("rows",array);

    rs.close();
    stmt.close();
    con.close();
    out.write(jsonObj2.toString());
%>

4、添加用户

<%@ page import="org.json.*" %>
<%@ page import="java.sql.Connection" %>
<%@ page import="java.sql.ResultSet" %>
<%@ page import="java.sql.ResultSetMetaData" %>
<%@ page import="java.sql.Statement" %>

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%

    //获取user参数
    String firstname= request.getParameter("firstname");
    String lastname= request.getParameter("lastname");
    String phone= request.getParameter("phone");
    String email= request.getParameter("email");
     JSONObject result = new JSONObject();
    int id=0;
    String DB_driver="com.mysql.jdbc.Driver";
    String u="jdbc:mysql://localhost/test?user=root&password=root&useUnicode=true&characterEncoding=GBK";

    Class.forName(DB_driver);
       java.sql.Connection con = java.sql.DriverManager.getConnection(u);
    java.sql.Statement stmt =con.createStatement(); 

    String sql="insert into users(firstname,lastname,phone,email) values(‘"+firstname+"‘,‘"+lastname+"‘,‘"+phone+"‘,‘"+email+"‘)";

     int flag=stmt.executeUpdate(sql, Statement.RETURN_GENERATED_KEYS);
     java.sql.ResultSet rs =  stmt.getGeneratedKeys();
     if (rs.next()) {
            id = rs.getInt(1);
     }
     sql="select * from users where id="+id;
     rs=stmt.executeQuery(sql);
     if(rs.next()){
        result.put("id",rs.getInt("id"));
        result.put("firstname",rs.getString("firstname"));
        result.put("lastname",rs.getString("lastname"));
        result.put("phone",rs.getString("phone"));
        result.put("email",rs.getString("email"));
     }
    else{
        result.put("errorMsg","insert data failed");
    }
    stmt.close();
    con.close();
    out.write(result.toString());
%>

5、删除用户

<%@ page import="org.json.*" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%

    //获取user参数
    String firstname= request.getParameter("firstname");
    String lastname= request.getParameter("lastname");
    String phone= request.getParameter("phone");
    String email= request.getParameter("email");
    int id=Integer.parseInt(request.getParameter("id"));
    JSONObject result = new JSONObject();
    String DB_driver="com.mysql.jdbc.Driver";
    String u="jdbc:mysql://localhost/test?user=root&password=root&useUnicode=true&characterEncoding=GBK";

    Class.forName(DB_driver);
       java.sql.Connection con = java.sql.DriverManager.getConnection(u);
    java.sql.Statement stmt =con.createStatement(); 

    String sql="delete from users  where id=‘"+id+"‘";

     int flag=stmt.executeUpdate(sql);
  if(flag>0){
      result.put("success","true");
  }
   else{
      result.put("errorMsg","this is wrong");
   }

    stmt.close();
    con.close();
    out.write(result.toString());
%>

6、最终效果

修改用户

删除用户