1
我有一個MySQL表中的列applicant_id, profession_id, last_name, first_name and entrance_year。我需要獲取數據庫的內容。 我寫的方法： 這就是我的課：不能看到數據庫mysql的內容。使用JSP/JDBC
public class Applicant extends Entity {
private long professionId;
private String lastName;
private String firstName;
private int entranceYear;
public Applicant() {
this.id = -1;
}
public Applicant(long professionId, String lastName, String firstName, int entranceYear) {
this.professionId = professionId;
this.lastName = lastName;
this.firstName = firstName;
this.entranceYear = entranceYear;
}
public long getProfessionId() {
return professionId;
}
public void setProfessionId(long professionId) {
this.professionId = professionId;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public int getEntranceYear() {
return entranceYear;
}
public void setEntranceYear(int entranceYear) {
this.entranceYear = entranceYear;
}
}
這是我的方法，這個節目數據庫的內容：
public List<Applicant> getApplicants() throws Exception {
Statement statement = null;
List <Applicant> applicants = new ArrayList<>();
try {
statement = connection.createStatement();
ResultSet resultSet = statement.executeQuery("SELECT * FROM applicant");
Applicant applicant = new Applicant();
while (resultSet.next()) {
applicant.setId(resultSet.getInt("applicant_id"));
applicant.setFirstName(resultSet.getString("first_name"));
applicant.setLastName(resultSet.getString("last_name"));
applicant.setProfessionId(resultSet.getInt("profession_id"));
applicant.setEntranceYear(resultSet.getInt("entrance_year"));
applicants.add(applicant);
}
} catch (SQLException e) {
throw new Exception(e);
}
return applicants;
}
和JSP申請人：
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<title></title>
</head>
<body>
<h1>Applicants</h1>
<c:choose>
<c:when test="${applicants.size() == 0}">
<p><c:out value="No applicants yet"></c:out></p>
</c:when>
<c:otherwise>
<table>
<tr>
<th>ID</th>
<th>First Name</th>
<th>Last Name</th>
<th>Profession ID</th>
<th>Entrance Year</th>
<th>Actions</th>
</tr>
<c:forEach items="${applicants}" var="applicant">
<tr>
<td>
<c:out value="${applicant.getId()}"/>
</td>
<td>
<c:out value="${applicant.getFirstName()}"/>
</td>
<td>
<c:out value="${applicant.getLastName()}"/>
</td>
<td>
<c:out value="${applicant.getProfessionId()}"/>
</td>
<td>
<c:out value="${applicant.getEntranceYear()}"/>
</td>
<td>
<a href="controller?command=deleteApplicant&id=${applicant.getId()}">Delete</a>
<a href="controller?command=editApplicant&id=${applicant.getId()}">Edit</a>
</td>
</tr>
</c:forEach>
</table>
</c:otherwise>
</c:choose>
<a href="controller?command=addApplicant">Add new applicant</a>
</body>
</html>
當我輸入數據庫實例的值爲5，我得到了五個相同值的列表！看：
5 John Smit 2 2008
5 John Smit 2 2008
5 John Smit 2 2008
5 John Smit 2 2008
5 John Smit 2 2008
所有內容是相同的，但我寫不同的數據。
5 John Smit 2 2008
這是最後一個內容，我把它放入數據庫。
的時候，我打開mysql數據庫，我可以看到：
1 Duke Nukem 1 2007
2 The Rock 2 2006
3 Rey Junior 3 2009
4 Randy Orton 1 2012
5 John Smit 2 2008
如何解決這個問題，請告訴我。
謝謝。