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JSP+beans实现读取数据库的例子
jsp+beans实现读取数据库的例子
Select.jsp
<html>
<head>
<title>Select everything from a database</title>
</head>
<body>
<jsp:useBean id="select" class="DataBaseSelect" scope="request">
</bean>
<% out.print(select.connect()); %>
<br>
<% out.print(select.select()); %>
<p>Format results
<br>
<%@ page import="Java.util.Vector" %>
<% Vector aResult = select.getResult(); %>
<table>
<% for (int i=0; i < aResult.size(); i++) { %>
<tr>
<td>
<% out.print(aResult.elementAt(i)); %>
</td>
</tr>
<% } %>
</table>
</body>
</html>
DataBaseSelect.java
import java.sql.*;
import java.util.Vector;
/**
* DataBaseSelect.java
* Written by Morgan Catlin
* August 19, 1999
*
* Variables:
* Vector result = where I put the results of a select query
*
* Methods:
* Vector getResult() = returns result
* void setResult() = sets result
* String connect() = connects to a database
* String select() = selects information from a database
*/
public class DataBaseSelect {
private Vector result;
public DataBaseSelect() {
result = new Vector();
} // constructor DataBaseSelect
public String connect() {
try {
Class.forName("a JDBC driver").newInstance();
return "Driver Loaded!";
} catch (Exception E) {
return "Unable to load driver.";
}
}
public String select() {
try {
Connection C = DriverManager.getConnection("database connection string");
Statement Stmt = C.createStatement();
ResultSet myResult = Stmt.executeQuery("SELECT acolumn from atable");
while (myResult.next()) {
result.addElement(myResult.getString(1));
}
// Clean up
myResult.close();
Stmt.close();
C.close();
return "Connection Success!";
} catch (SQLException E) {
return "SQLException: " + E.getMessage();
}
}
/**
* Accessor for result
**/
public Vector getResult() {
return result;
}
/**
* Mutator for result
**/
public void setResult(Vector avector) {
result = avector;
}
} // class DataBaseSelect
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