做作业工程中遇到一些问题，特此记录一下
解决的问题：使用EasyUI框架搭建简单学生管理系统（数据库增删改查）操作时配合JSP，不知道如何把从数据库获得的数据封装成JSON格式并传回前端JSP并进行展示
解决工具：Servlet、MVC设计模式
1.数据封装
//连接数据库Connection connection=null;String driverName="com.microsoft.sqlserver.jdbc.SQLServerDriver";//SQL数据库引擎String dbURL="jdbc:sqlserver://localhost:1433;DatabaseName=tjl";//数据源 ！！！注意若出现加载或者连接数据库失败一般是这里出现问题String Name="sa";String Pwd="19990713";ResultSet rs=null;//定义JSON数组，用于保存从数据库查出来的数据JSONArray array = new JSONArray();try{Class.forName(driverName);connection=DriverManager.getConnection(dbURL,Name,Pwd);System.out.println("连接数据库成功");}catch(Exception e){e.printStackTrace();System.out.println("连接失败");}Statement stmt = null;try {stmt = connection.createStatement();} catch (SQLException e) {// TODO Auto-generated catch block e.printStackTrace();}/*//增删改操作String sql_1="insert into student values('990403','佩奇','男','12','1','2101')";int count_1 = 0;try {count_1 = stmt.executeUpdate(sql_1);} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}//返回值表示增删改几条数据//处理结果if(count_1>0){System.out.println("更新成功!");}*///查询操作String sql_2="select * from student";try {rs = stmt.executeQuery(sql_2);// 获取列数ResultSetMetaData metaData = rs.getMetaData();int columnCount = metaData.getColumnCount();while (rs.next()) {JSONObject jsonObj = new JSONObject();// 遍历每一列for (int i = 1; i <= columnCount; i++) {String columnName =metaData.getColumnLabel(i);String value = rs.getString(columnName);jsonObj.put(columnName, value);} array.put(jsonObj); }} catch (SQLException e1) {e1.printStackTrace();}
2.Servlet基础知识
3.在Ecplise内创建Servlet
在您所创建的WEB项目的src目录右键新建，如图，选择Servlet，如果有版本选项，选择3.0版本，系统会自动创建映射和基本都代码格式
4.完整代码
package com.jwglxt.data;import java.io.IOException;import java.io.PrintWriter;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.ResultSetMetaData;import java.sql.SQLException;import java.sql.Statement;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.json.JSONArray;import org.json.JSONObject;@WebServlet("/getStudent")public class getStudent extends HttpServlet {protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//设置编码格式request.setCharacterEncoding("UTF-8"); response.setCharacterEncoding("utf-8");response.setContentType("text/json; charset=utf-8");//连接数据库Connection connection=null;String driverName="com.microsoft.sqlserver.jdbc.SQLServerDriver";//SQL数据库引擎String dbURL="jdbc:sqlserver://localhost:1433;DatabaseName=tjl";//数据源 ！！！注意若出现加载或者连接数据库失败一般是这里出现问题String Name="sa";String Pwd="19990713";ResultSet rs=null;//定义JSON数组，用于保存从数据库查出来的数据JSONArray array = new JSONArray();try{Class.forName(driverName);connection=DriverManager.getConnection(dbURL,Name,Pwd);System.out.println("连接数据库成功");}catch(Exception e){e.printStackTrace();System.out.println("连接失败");}Statement stmt = null;try {stmt = connection.createStatement();} catch (SQLException e) {// TODO Auto-generated catch block e.printStackTrace();}/*//增删改操作String sql_1="insert into student values('990403','佩奇','男','12','1','2101')";int count_1 = 0;try {count_1 = stmt.executeUpdate(sql_1);} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}//返回值表示增删改几条数据//处理结果if(count_1>0){System.out.println("更新成功!");}*///查询操作String sql_2="select * from student";try {rs = stmt.executeQuery(sql_2);// 获取列数ResultSetMetaData metaData = rs.getMetaData();int columnCount = metaData.getColumnCount();while (rs.next()) {JSONObject jsonObj = new JSONObject();// 遍历每一列for (int i = 1; i <= columnCount; i++) {String columnName =metaData.getColumnLabel(i);String value = rs.getString(columnName);jsonObj.put(columnName, value);} array.put(jsonObj); }} catch (SQLException e1) {e1.printStackTrace();}//关闭try {if(rs!=null) rs.close();stmt.close();connection.close();} catch (SQLException e) {e.printStackTrace();}PrintWriter out = response.getWriter();out.println(array);}protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doGet(request, response);}}
5.EasyUI引用数据
参考文章：/qq_38313548/article/details/85966603
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