在jsp bean中找不到符号错误
谢谢你阅读这个问题 下面的代码 我正在尝试让jsp与数据库一起工作。数据库当前已部分填充，我正在尝试将此信息返回到浏览器并打印出来 不幸的是，当我尝试这样做时，我得到一个错误，即编译器在我尝试在newjsp.jsp中调用getStudentList（）的行中找不到符号“studentData” 我从一个朋友的项目中复制了newjsp中的代码，该项目运行良好 我希望你能帮忙 谢谢 工厂182 *********StudentBean.java******在jsp bean中找不到符号错误,jsp,symbols,Jsp,Symbols,谢谢你阅读这个问题 下面的代码 我正在尝试让jsp与数据库一起工作。数据库当前已部分填充，我正在尝试将此信息返回到浏览器并打印出来 不幸的是，当我尝试这样做时，我得到一个错误，即编译器在我尝试在newjsp.jsp中调用getStudentList（）的行中找不到符号“studentData” 我从一个朋友的项目中复制了newjsp中的代码，该项目运行良好 我希望你能帮忙 谢谢 工厂182 *********StudentBean.java****** package my.b
package my.beans;
public class StudentBean {
private String firstName;
private String lastName;
private String comment;
private String email;
public StudentBean(){
}
// get/set for First Name
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getFirstName(){
return firstName;
}
// get/set for Last Name
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getLastName(){
return lastName;
}
// get/set for comment
public void setComment(String comment) {
this.comment = comment;
}
public String getComment(){
return comment;
}
// get/set for Email
public void setEmail(String email) {
this.email = email;
}
public String getEmail(){
return email;
}
}
package my.beans;
import java.sql.SQLException;
import javax.sql.rowset.CachedRowSet;
import java.util.ArrayList;
import com.sun.rowset.CachedRowSetImpl; // CachedRowSet implementation
public class StudentDataBean {
private CachedRowSet rowSet;
// construct TitlesBean object
public StudentDataBean() throws Exception
{
// load the MySQL driver
Class.forName( "com.mysql.jdbc.Driver" );
// specify properties of CachedRowSet
rowSet = new CachedRowSetImpl();
rowSet.setUrl( "jdbc:mysql://localhost:3306/test" );
rowSet.setUsername( "root" );
rowSet.setPassword( "" );
// obtain list of titles
rowSet.setCommand(
"SELECT firstName, lastName, email, comment FROM guests" );
rowSet.execute();
} // end StudentDataBean constructor
// return an ArrayList of StudnetBeans
public ArrayList<StudentBean> getStudentList() throws SQLException
{
ArrayList<StudentBean> studentList = new ArrayList<StudentBean>();
rowSet.beforeFirst(); // move cursor before the first row
// get row data
while ( rowSet.next() )
{
StudentBean student = new StudentBean();
student.setFirstName( rowSet.getString( 1 ) );
student.setLastName( rowSet.getString( 2 ) );
student.setEmail( rowSet.getString( 3 ) );
student.setComment( rowSet.getString( 4 ) );
studentList.add( student );
} // end while
return studentList;
} // end method getStudentList
// insert a Student in student database
public void addStudent( StudentBean student ) throws SQLException
{
rowSet.moveToInsertRow(); // move cursor to the insert row
// update the three columns of the insert row
rowSet.updateString( 1, student.getFirstName() );
rowSet.updateString( 2, student.getLastName() );
rowSet.updateString( 3, student.getEmail() );
rowSet.updateString( 4, student.getComment() );
rowSet.insertRow(); // insert row to rowSet
rowSet.moveToCurrentRow(); // move cursor to the current row
rowSet.acceptChanges(); // propagate changes to database
} // end method addStudent
} // end class StudentDataBean
<%@page import="java.util.ArrayList"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%@ page import="java.util.*" %>
<%@ page import="my.beans.StudentDataBean"%>
<%@ page import="my.beans.StudentBean"%>
<jsp:useBean id="studentData" scope="request" class="my.beans.StudentDataBean"/>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Words View</title>
<style type="text/css">
table, tr, td, th
{
text-algn: center;
font-size: .9em;
border: 3px groove;
padding: 3px;
background-color: #eee9e9;
}
</style>
</head>
<body>
<h1>Student List</h1>
<table border="1">
<tr>
<th>
<h4>Email</h4>
</th>
</tr>
<%
ArrayList<StudentBean> studentList = studentData.getStudentList();
Iterator studentListIterator = studentList.iterator();
StudentBean student;
while (studentListIterator.hasNext()){
student = (StudentBean) studentListIterator.next();
%>
<tr>
<td><%= student.getEmail()%></td>
</tr>
<% }
%>
</table>
</body>
</html>
package my.beans;
public class StudentBean {
private String firstName;
private String lastName;
private String comment;
private String email;
public StudentBean(){
}
// get/set for First Name
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getFirstName(){
return firstName;
}
// get/set for Last Name
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getLastName(){
return lastName;
}
// get/set for comment
public void setComment(String comment) {
this.comment = comment;
}
public String getComment(){
return comment;
}
// get/set for Email
public void setEmail(String email) {
this.email = email;
}
public String getEmail(){
return email;
}
}
package my.beans;
import java.sql.SQLException;
import javax.sql.rowset.CachedRowSet;
import java.util.ArrayList;
import com.sun.rowset.CachedRowSetImpl; // CachedRowSet implementation
public class StudentDataBean {
private CachedRowSet rowSet;
// construct TitlesBean object
public StudentDataBean() throws Exception
{
// load the MySQL driver
Class.forName( "com.mysql.jdbc.Driver" );
// specify properties of CachedRowSet
rowSet = new CachedRowSetImpl();
rowSet.setUrl( "jdbc:mysql://localhost:3306/test" );
rowSet.setUsername( "root" );
rowSet.setPassword( "" );
// obtain list of titles
rowSet.setCommand(
"SELECT firstName, lastName, email, comment FROM guests" );
rowSet.execute();
} // end StudentDataBean constructor
// return an ArrayList of StudnetBeans
public ArrayList<StudentBean> getStudentList() throws SQLException
{
ArrayList<StudentBean> studentList = new ArrayList<StudentBean>();
rowSet.beforeFirst(); // move cursor before the first row
// get row data
while ( rowSet.next() )
{
StudentBean student = new StudentBean();
student.setFirstName( rowSet.getString( 1 ) );
student.setLastName( rowSet.getString( 2 ) );
student.setEmail( rowSet.getString( 3 ) );
student.setComment( rowSet.getString( 4 ) );
studentList.add( student );
} // end while
return studentList;
} // end method getStudentList
// insert a Student in student database
public void addStudent( StudentBean student ) throws SQLException
{
rowSet.moveToInsertRow(); // move cursor to the insert row
// update the three columns of the insert row
rowSet.updateString( 1, student.getFirstName() );
rowSet.updateString( 2, student.getLastName() );
rowSet.updateString( 3, student.getEmail() );
rowSet.updateString( 4, student.getComment() );
rowSet.insertRow(); // insert row to rowSet
rowSet.moveToCurrentRow(); // move cursor to the current row
rowSet.acceptChanges(); // propagate changes to database
} // end method addStudent
} // end class StudentDataBean
<%@page import="java.util.ArrayList"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%@ page import="java.util.*" %>
<%@ page import="my.beans.StudentDataBean"%>
<%@ page import="my.beans.StudentBean"%>
<jsp:useBean id="studentData" scope="request" class="my.beans.StudentDataBean"/>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Words View</title>
<style type="text/css">
table, tr, td, th
{
text-algn: center;
font-size: .9em;
border: 3px groove;
padding: 3px;
background-color: #eee9e9;
}
</style>
</head>
<body>
<h1>Student List</h1>
<table border="1">
<tr>
<th>
<h4>Email</h4>
</th>
</tr>
<%
ArrayList<StudentBean> studentList = studentData.getStudentList();
Iterator studentListIterator = studentList.iterator();
StudentBean student;
while (studentListIterator.hasNext()){
student = (StudentBean) studentListIterator.next();
%>
<tr>
<td><%= student.getEmail()%></td>
</tr>
<% }
%>
</table>
</body>
</html>
打包my.beans；
导入java.sql.SQLException；
导入javax.sql.rowset.CachedRowSet；
导入java.util.ArrayList；
导入com.sun.rowset.CachedRowSetImpl；//CachedRowSet实现
公共班级学生数据库{
私有CachedRowSet行集；
//构造标题bean对象
public StudentDataBean（）引发异常
{
//加载MySQL驱动程序
Class.forName（“com.mysql.jdbc.Driver”）；
//指定CachedRowSet的属性
行集=新的CachedRowSetImpl（）；
setUrl（“jdbc:mysql://localhost:3306/test" );
rowSet.setUsername（“根”）；
rowSet.setPassword（“”）；
//获取标题列表
rowSet.setCommand(
“选择名字、姓氏、电子邮件、客人评论”）；
rowSet.execute（）；
}//end StudentDataBean构造函数
//返回StudnetBeans的ArrayList
公共ArrayList getStudentList（）引发SQLException
{
ArrayList studentList=新建ArrayList（）；
rowSet.beforeFirst（）；//将光标移到第一行之前
//获取行数据
while（rowSet.next（））
{
StudentBean student=newstudentbean（）；
student.setFirstName（rowSet.getString（1））；
student.setLastName（rowSet.getString（2））；
setEmail（rowSet.getString（3））；
setComment（rowSet.getString（4））；
学生列表。添加（学生）；
}//结束时
返回学生名单；
}//结束方法getStudentList
//在学生数据库中插入学生
public void addStudent（StudentBean student）引发SQLException
{
rowSet.moveToInsertRow（）；//将光标移动到插入行
//更新插入行的三列
updateString（1，student.getFirstName（））；
updateString（2，student.getLastName（））；
updateString（3，student.getEmail（））；
updateString（4，student.getComment（））；
rowSet.insertRow（）；//将行插入到行集
rowSet.moveToCurrentRow（）；//将光标移动到当前行
rowSet.acceptChanges（）；//将更改传播到数据库
}//结束方法addStudent
}//结束类StudentDataBean
package my.beans;
public class StudentBean {
private String firstName;
private String lastName;
private String comment;
private String email;
public StudentBean(){
}
// get/set for First Name
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getFirstName(){
return firstName;
}
// get/set for Last Name
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getLastName(){
return lastName;
}
// get/set for comment
public void setComment(String comment) {
this.comment = comment;
}
public String getComment(){
return comment;
}
// get/set for Email
public void setEmail(String email) {
this.email = email;
}
public String getEmail(){
return email;
}
}
package my.beans;
import java.sql.SQLException;
import javax.sql.rowset.CachedRowSet;
import java.util.ArrayList;
import com.sun.rowset.CachedRowSetImpl; // CachedRowSet implementation
public class StudentDataBean {
private CachedRowSet rowSet;
// construct TitlesBean object
public StudentDataBean() throws Exception
{
// load the MySQL driver
Class.forName( "com.mysql.jdbc.Driver" );
// specify properties of CachedRowSet
rowSet = new CachedRowSetImpl();
rowSet.setUrl( "jdbc:mysql://localhost:3306/test" );
rowSet.setUsername( "root" );
rowSet.setPassword( "" );
// obtain list of titles
rowSet.setCommand(
"SELECT firstName, lastName, email, comment FROM guests" );
rowSet.execute();
} // end StudentDataBean constructor
// return an ArrayList of StudnetBeans
public ArrayList<StudentBean> getStudentList() throws SQLException
{
ArrayList<StudentBean> studentList = new ArrayList<StudentBean>();
rowSet.beforeFirst(); // move cursor before the first row
// get row data
while ( rowSet.next() )
{
StudentBean student = new StudentBean();
student.setFirstName( rowSet.getString( 1 ) );
student.setLastName( rowSet.getString( 2 ) );
student.setEmail( rowSet.getString( 3 ) );
student.setComment( rowSet.getString( 4 ) );
studentList.add( student );
} // end while
return studentList;
} // end method getStudentList
// insert a Student in student database
public void addStudent( StudentBean student ) throws SQLException
{
rowSet.moveToInsertRow(); // move cursor to the insert row
// update the three columns of the insert row
rowSet.updateString( 1, student.getFirstName() );
rowSet.updateString( 2, student.getLastName() );
rowSet.updateString( 3, student.getEmail() );
rowSet.updateString( 4, student.getComment() );
rowSet.insertRow(); // insert row to rowSet
rowSet.moveToCurrentRow(); // move cursor to the current row
rowSet.acceptChanges(); // propagate changes to database
} // end method addStudent
} // end class StudentDataBean
<%@page import="java.util.ArrayList"%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<%@ page import="java.util.*" %>
<%@ page import="my.beans.StudentDataBean"%>
<%@ page import="my.beans.StudentBean"%>
<jsp:useBean id="studentData" scope="request" class="my.beans.StudentDataBean"/>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Words View</title>
<style type="text/css">
table, tr, td, th
{
text-algn: center;
font-size: .9em;
border: 3px groove;
padding: 3px;
background-color: #eee9e9;
}
</style>
</head>
<body>
<h1>Student List</h1>
<table border="1">
<tr>
<th>
<h4>Email</h4>
</th>
</tr>
<%
ArrayList<StudentBean> studentList = studentData.getStudentList();
Iterator studentListIterator = studentList.iterator();
StudentBean student;
while (studentListIterator.hasNext()){
student = (StudentBean) studentListIterator.next();
%>
<tr>
<td><%= student.getEmail()%></td>
</tr>
<% }
%>
</table>
</body>
</html>
词语观
表，tr，td，th
{
文本algn：中心；
字体大小：.9em；
边框：3px凹槽；
填充：3倍；
背景色：#eee9e9；
}
学生名单
电子邮件