html调用servlet（JDBC在Servlet中的使用）（2）
5.修改数据
5.1编写查询条件页面
修改单条数据的时候，首先是查询出单个数据的详细信息，然后根据实际需要部分修改或者全部修改。修改之后，数据会提交到数据库，数据库中保存更新以后的数据。
查询出单条数据的查询条件页面代码如下：
QueryToUpdate.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>QueryToUpdate.html</title> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=UTF-8"> <!--<link rel="stylesheet" type="text/css" href="./styles.css">--> </head> <body>
<form name="f1" id="f1" action="/jdbc_servlet/servlet/QueryToUpdateServlet" method="post">
<table border="0">
<tr>
<td>请输入要修改的部门编号:</td><tr></tr>
<td><input type="text" name="id" ></td>
</tr>
<tr>
<td colspan="2" align="left"><input type="submit" value="提交"></td>
</tr>
</table>
</form>
</body>
</html>
5.2 编写显示部门详细信息的Servlet
输入要修改的部门编号以后，进入根据部门编号查询部门信息的Servlet，把部门详细信息显示到页面中，一些不可以修改的字段可以设置成只读，这样就不会把这些数据修改了，该Servlet的代码如下：
QueryToUpdateServlet.java
package com.cn.update; import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException; import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; public class QueryToUpdateServlet extends HttpServlet { /**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
} /**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html;charset=gb2312");
request.setCharacterEncoding("gb2312");
PrintWriter out = response.getWriter();
String id = request.getParameter("id");
Connection con = null;
PreparedStatement pstmt = null;
ResultSet rs = null;
try {
Class.forName("com.mysql.jdbc.Driver");
System.out.println("创建驱动成功！");
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/bank", "root", "1234");
System.out.println("数据库连接成功！");
String sql = "SELECT * FROM dept WHERE id=?";
pstmt = con.prepareStatement(sql);
pstmt.setString(1, id);
rs = pstmt.executeQuery();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//显示单个部门的信息
out.println("<html>"
+ "<head><title>显示单个部门信息</title></head>"
+ "<body>");
out.println("<h1>显示单个部门信息</h1><br><br>");
out.print("<form action='/jdbc_servlet/servlet/UpdateDeptServlet' method='post'>");
try {
while(rs.next()){
out.println("部门编号：");
out.print("<br>");
//在文本框中显示部门编号，设置成只读
out.println("<input type='text' name='id' readonly='true' value=");
out.println(rs.getString(1).toString());
out.print(">");
out.print("<br>");
out.println("部门名称：");
out.print("<br>");
//在文本框中显示部门名称
out.println("<input type='text' name='d_name' value=");
out.println(rs.getString(2).toString());
out.print(">");
out.print("<br>");
out.println("部门地址：");
out.print("<br>");
//在文本框中显示部门地址
out.println("<input type='text' name='address' value=");
out.println(rs.getString(3).toString());
out.print(">");
out.print("<br>");
out.println("部门人数：");
out.print("<br>");
//在文本框中显示部门人数
out.println("<input type='text' name='empnumber' value=");
out.println(rs.getString(4).toString());
out.print(">");
out.print("<br>");
//提交按钮
out.print("<input type='submit' value='Submit'>");
out.print("</form>"); }
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
out.flush();
out.close();
} /**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html;charset=gb2312");
request.setCharacterEncoding("gb2312");
PrintWriter out = response.getWriter();
this.doGet(request, response);
out.flush();
out.close();
} /**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
} }
5.3编写处理修改操作的Servlet
在UpdateDeptServlet中，修改数据以后，显示出数据库表中的全部信息。UpdateDeptServlet的代码如下：
UpdateDeptServlet.java
package com.cn.update; import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement; import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; public class UpdateDeptServlet extends HttpServlet { /**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html");
PrintWriter out = response.getWriter();
this.doPost(request, response);
out.flush();
out.close();
} /**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html;charset=gb2312");
request.setCharacterEncoding("gb2312");
PrintWriter out = response.getWriter();
Connection con = null;
PreparedStatement ps = null;
ResultSet rs = null;
Statement sta = null;
String id = request.getParameter("id");
String address = request.getParameter("address");
int empnumber = Integer.parseInt(request.getParameter("empnumber"));
String d_name = request.getParameter("d_name");
try {
Class.forName("com.mysql.jdbc.Driver");
System.out.println("创建驱动成功！");
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/bank", "root", "1234");
System.out.println("数据库连接成功！");
String sql = "UPDATE dept SET id=?,address=?,empnumber=?,d_name=? WHERE id=?";
ps = con.prepareStatement(sql);
//下面设置修改的数据值
ps.setString(1, id);
ps.setString(2, address);
ps.setInt(3, empnumber);
ps.setString(4, d_name);
ps.setString(5, id);
ps.executeUpdate();
System.out.println("修改成功！");
/*
* 添加成功后，显示全部信息
*/
sta = con.createStatement();
rs = sta.executeQuery("SELECT * FROM dept");
//在页面中显示表中的所有信息
out.println(
"<html>"+
"<head><title>部门表信息</title></head>"+
"<body>");
out.println("<h1>部门表信息:</h1><br><br>");
//循环遍历输出查询结果
while(rs.next()){
out.print("部门编号：");
out.print(rs.getString(1)+"\t");
out.print("部门名称：");
out.print(rs.getString(2)+"\t");
out.print("部门地址：");
out.print(rs.getString(3)+"\t");
out.print("部门人数：");
out.print(rs.getString(4)+"\t");
out.println("<br>");
}
out.print("</body></html>");
out.close();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
out.flush();
out.close();
} /**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
} }
6. 删除数据
删除数据时，要指定删除的条件，否则会把表中的所有数据删除。删除以后，被删除的数据在表中就不存在了。下面的例子是根据部门编号删除数据的例子。首先在页面中输入要删除的部门编号，输入要删除的部门编号的页面代码入下：
delete.html
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>delete.html</title> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
<meta http-equiv="description" content="this is my page">
<meta http-equiv="content-type" content="text/html; charset=gb2312"> <!--<link rel="stylesheet" type="text/css" href="./styles.css">--> </head> <body>
<form name="f1" id="f1" action="/jdbc_servlet/servlet/DeleteByIdServlet" method="post">
<table border="0">
<tr>
<td>请输入要删除的部门编号:</td><tr></tr>
<td><input type="text" name="id" ></td>
</tr>
<tr>
<td colspan="2" align="left"><input type="submit" value="删除"></td>
</tr>
</table>
</form>
</body>
</html>
当输入删除条件后，单击【删除】按钮，会进入form表单指定的DeleteByIdServlet中，这是一个servlet，用来处理删除操作。DeleteByIdServlet中的代码如下：
DeleteByIdServlet.java
package com.cn.delete; import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException; import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse; public class DeleteByIdServlet extends HttpServlet { /**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html");
PrintWriter out = response.getWriter();
this.doPost(request, response);
out.flush();
out.close();
} /**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException { response.setContentType("text/html;charset=gb2312");
request.setCharacterEncoding("gb2312");
PrintWriter out = response.getWriter();
String id = request.getParameter("id");
Connection con = null;
// ResultSet rs = null;
PreparedStatement ps = null;
try {
Class.forName("com.mysql.jdbc.Driver");
System.out.println("创建驱动成功！");
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/bank", "root", "1234");
System.out.println("数据库连接成功！");
String sql = "DELETE FROM dept WHERE id=?";
ps = con.prepareStatement(sql);
ps.setString(1, id);
ps.executeUpdate();
System.out.println("删除成功！");
//显示结果信息
out.println("<html><head><title>"
+"删除部门表数据</title></head>"+"<body>");
out.println("<h1>删除部门表数据成功！</h1>");
out.print("</body></html>");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
out.flush();
out.close();
} /**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
} }
在DeleteByIdServlet中，获得页面传递过来的部门编号，然后根据部门编号删除该编号对应的数据，删除成功则在页面中提示删除成功。
html调用servlet（JDBC在Servlet中的使用）（2）的更多相关文章
- html调用servlet（JDBC在Servlet中的使用）（1）
1.页面的数据表单 在使用Servlet处理用户请求之前,先准备一个页面,该页面用来提供数据表单.数据表单就是HTML中的<form>...</form>部分,当用户单击Sub ...
- Java Servlet(三)：Servlet中ServletConfig对象和ServletContext对象
本文将记录ServletConfig/ServletContext中提供了哪些方法,及方法的用法. ServletConfig是一个抽象接口,它是由Servlet容器使用,在一个servlet对象初始 ...
- 登录小项目 js+servlet+jdbc+mvc
项目名称: 沪上阿姨 实现需求: 实现用户登录 实现用户退出 实现用户注册 功能分析: 用户登录: 根据用户名和密码查询用户信息.查询则登录成功,查不到则登录失败. 用户退出: 销毁session 用 ...
- JDBC和servlet设计思路、DAO模式思路、MVC思路粗略总结
#JDBC和Servlet联合起来使用的项目思路: 说明:建库,最好一开始设置utf8字符集 step1: 在数据库中建表 如 create table t_user{ ...... } step ...
- Jsp+Servlet+JDBC的使用复习
最近对JDBC进行了复习,对事物的理解,连接池的使用等部分都有一个复习,所以使用Servlet+JDBC完成了一个小Demo,在这里对这种底层的操作进行总结.框架的使用的确方便了我们的开发,但是底层的 ...
- java web开发基础实例（javabean+jsp+servlet+jdbc）
JavaBean:用于传递数据,拥有与数据相关的逻辑处理 JSP:从Model接收数据并生成HTML Servlet:接收HTTP请求并控制Model和View jdbc:用于配置环境 一.[建立数据 ...
- 使用JSP+Servlet+Jdbc+Echatrs实现对豆瓣电影Top250的展示
使用JSP+Servlet+Jdbc+Echatrs实现对豆瓣电影Top250的展示 写在前面: 有的小伙伴,会吐槽啦,你这个标题有点长的啊.哈哈 ,好像是的!不过,这个也是本次案例中使用到的关键技术 ...
- 使用servlet+jdbc+MD5实现用户加密登录
/** * 分析流程: * 1.前端页面提交登录请求 * 2.被web.xml拦截,进入到LoginServlet(有两种方式:方式一,在web.xml文件中配置servlet拦截器;方式二,不用在w ...
- Servlet从本地文件中读取图片，并显示在页面中
import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpSer ...
- MVC-1(javabean+jsp+servlet+jdbc)
这是一篇最初版本的mvc设计模式的demo.路要一步一步走,弄明白这其中的逻辑,对后面掌握ssh,ssm等框架大有裨益. 计算机系的同学们也要为毕设做准备了,希望可以帮你们迈出自己做毕设的第一步(微笑 ...
随机推荐
- 查看锁信息（开启InnoDB监控）
当前mysql版本:5.6.21 一.背景 在mysql处理死锁问题时,由于show engine innodb status输出来的死锁日志无任务事务上下文,并不能很好地诊断相关事务所持有的所有锁信 ...
- http远程调用原生get、post模板
一.get方法 package lq.httpclient.method; import java.io.BufferedReader; import java.io.IOException; imp ...
- Python如何将RGB图像转换为Pytho灰度图像？
我正尝试使用matplotlib读取RGB图像并将其转换为灰度.在matlab中,我使用这个: 1 img = rgb2gray(imread('image.png')); 在matplotlib t ...
- cbv
- 「JSOI2018」战争
「JSOI2018」战争 解题思路 我们需要每次求给一个凸包加上一个向量后是否与另外一个凸包相交,也就是说是否存在 \[ b\in B,(b+w)\in A \] 这里 \(A, B\) 表示凸包内部 ...
- [BZOJ4372]烁烁的游戏(动态点分治+线段树)
和[BZOJ3730]震波几乎一样,每个点建两棵线段树分别代表它的管辖范围内以它为LCA的路径的贡献和它对父亲的贡献. 注意点分树上的点的距离在原树上不单调,所以不能有若距离超出限制就break之类的 ...
- [BZOJ2683]简单题/[BZOJ1176][BalkanOI2007]Mokia
[BZOJ2683]简单题 题目大意: 一个\(n\times n(n\le5\times10^5)\)的矩阵,初始时每个格子里的数全为\(0\).\(m(m\le2\times10^5)\)次操作, ...
- 【HDU】2866：Special Prime【数论】
Special Prime Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)Tot ...
- 【10.7校内测试】【队列滑窗】【2-sat】【贪心+栈二分+线段树（noip模拟好题）】【生日祭！】
比较好想的一道题,直接用队列滑窗,因为扫一遍往队列里加东西时,改变的只有一个值,开桶储存好就行了! #include<bits/stdc++.h> using namespace std; ...
- URAL 1880 Psych Up's Eigenvalues
1880. Psych Up's Eigenvalues Time limit: 0.5 secondMemory limit: 64 MB At one of the contests at the ...