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！！
时间： 2024-12-19 08:08:55