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编写过程中需要注意的问题：
1.建立eclipse动态web工程时，需要改写编译后class文件的位置，通常情况下是这个位置：/WebContent/WEB-INF/classes
2.配置的页面链接和servlet类之间有两种方式：
1）通过在web.xml文件中进行配置：示例如下
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0"> <display-name>jspshow1</display-name> <servlet> <servlet-name>listTheStudent</servlet-name> <servlet-class>com.guodiantong.javaweb.ListTheStudent</servlet-class> </servlet> <servlet-mapping> <servlet-name>listTheStudent</servlet-name> <url-pattern>/list</url-pattern> </servlet-mapping> <servlet> <servlet-name>deleteTheStudent</servlet-name> <servlet-class>com.guodiantong.javaweb.DeleteServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>deleteTheStudent</servlet-name> <url-pattern>/delete</url-pattern> </servlet-mapping> </web-app>
2）通过在eclipse新建servlet时，自动指示设置页面请求和servlet类之间的链接关系：如下图所示
new--->servlet
这种也能实现请求和对应的servlet类之间的映射，通过这种方式你会发下，tomcat使用的注解的方式@WebServlet，这种方式在web.xml文件中并没有通过 1）的那种方式显现出来
谈完上述注意的地方，下面开始见工程：先看下项目的目录结构
先看下所有的jsp文件：test.jsp文件
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<a href="list">list all students</a>
</body>
</html>
students.jsp文件：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ page import="java.util.List" %>
<%@page import="com.guodiantong.javaweb.*" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%=request.getAttribute("students") %>
<br>
<%
List<Student> stus=(List<Student>)request.getAttribute("students");
%>
<table>
<tr>
<th>flowid</th>
<th>type</th>
<th>id_card</th>
<th>exam_card</th>
<th>studentname</th>
<th>location</th>
<th>grade</th>
<th>操作</th>
<%
for(Student student:stus){
%>
<tr>
<td><%=student.getFlowid() %></td>
<td><%=student.getType() %></td>
<td><%=student.getIdcard() %></td>
<td><%=student.getExam_card() %></td>
<td><%=student.getStudentname() %></td>
<td><%=student.getLocation() %></td>
<td><%=student.getGrade() %></td>
<td><a href="delete?flowid=<%=student.getFlowid() %>">删除</a></td>
</tr>
<%
}
%>
</table>
</body>
</html>
success.jsp文件：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
操作成功！！
<a href="list">refresh</a>
</body>
</html>
下面是servlet类的代码：List请求对应的servlet类：ListTheStudent.java
package com.guodiantong.javaweb; import java.io.IOException; import java.util.ArrayList; import java.util.List; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class ListTheStudent extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { List<Student> students=new ArrayList<Student>(); StudentDao studentDao=new StudentDao(); students=studentDao.getAll(); request.setAttribute("students", students); request.getRequestDispatcher("/students.jsp").forward(request, response); } }
delete请求对应的jservlet java类：DeleteServlet.java
package com.guodiantong.javaweb; import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; public class DeleteServlet extends HttpServlet { @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String flowid=request.getParameter("flowid"); StudentDao studentDao=new StudentDao(); studentDao.deleteStudent(flowid); request.getRequestDispatcher("/success.jsp").forward(request, response); } }
项目中最重要的StudentDao.java
package com.guodiantong.javaweb; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.util.ArrayList; import java.util.List; public class StudentDao { public List<Student> getAll(){ Connection connection=null; PreparedStatement preparedStatement=null; ResultSet resultSet=null; List<Student> students=new ArrayList<Student>(); try { String driverClass="com.mysql.jdbc.Driver"; String url="jdbc:mysql:///dsm"; String user="root"; String password="12345678"; Class.forName(driverClass); connection=DriverManager.getConnection(url, user, password); String sql="SELECT flow_id,Type,id_card,exam_card,student_name,location,grade " +"FROM examstudent"; preparedStatement=connection.prepareStatement(sql); resultSet=preparedStatement.executeQuery(); while(resultSet.next()){ String flowid=resultSet.getString(1); System.out.println(flowid); String type=resultSet.getString(2); String idcard=resultSet.getString(3); String exam_card=resultSet.getString(4); String studentname=resultSet.getString(5); String location=resultSet.getString(6); String grade=resultSet.getString(7); Student student=new Student(flowid, type, idcard, exam_card, studentname, location, grade); students.add(student); } } catch (Exception e) { e.printStackTrace(); }finally{ try { if(resultSet !=null){ resultSet.close(); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { if(preparedStatement !=null){ preparedStatement.close(); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { if(connection !=null){ connection.close(); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } return students; } public void deleteStudent(String flowid){ Connection connection=null; PreparedStatement preparedStatement=null; try { String driverClass="com.mysql.jdbc.Driver"; String url="jdbc:mysql:///dsm"; String user="root"; String password="12345678"; Class.forName(driverClass); connection=DriverManager.getConnection(url, user, password); String sql="DELETE FROM examstudent where flow_id=?"; preparedStatement=connection.prepareStatement(sql); preparedStatement.setString(1, flowid); preparedStatement.execute(); } catch (Exception e) { e.printStackTrace(); }finally{ try { if(preparedStatement !=null){ preparedStatement.close(); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } try { if(connection !=null){ connection.close(); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } }
项目中的javabean ：Student.java
package com.guodiantong.javaweb; public class Student { private String flowid; private String type; private String idcard; private String exam_card; private String studentname; private String location; private String grade; public String getFlowid() { return flowid; } public void setFlowid(String flowid) { this.flowid = flowid; } public String getType() { return type; } public void setType(String type) { this.type = type; } public String getIdcard() { return idcard; } public void setIdcard(String idcard) { this.idcard = idcard; } public String getExam_card() { return exam_card; } public void setExam_card(String exam_card) { this.exam_card = exam_card; } public String getStudentname() { return studentname; } public void setStudentname(String studentname) { this.studentname = studentname; } public String getLocation() { return location; } public void setLocation(String location) { this.location = location; } public String getGrade() { return grade; } public void setGrade(String grade) { this.grade = grade; } public Student() { super(); } public Student(String flowid, String type, String idcard, String exam_card, String studentname, String location, String grade) { super(); this.flowid = flowid; this.type = type; this.idcard = idcard; this.exam_card = exam_card; this.studentname = studentname; this.location = location; this.grade = grade; } @Override public String toString() { return "Student [flowid=" + flowid + ", type=" + type + ", idcard=" + idcard + ", exam_card=" + exam_card + ", studentname=" + studentname + ", location=" + location + ", grade=" + grade + "]"; } }
提到javabean就需要看一下后台数据表格的结构：
就是这些！！
java web 入门实例servlet篇（显示后台数据库列表，删除某一条记录并显示）
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原文地址：http://www.cnblogs.com/zhangshitong/p/4870867.html
