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jsp+beans实现读取数据库的例子



作者:未知    文章来源:www.jspcn.net
发布日期:2005年01月19日
作者:asp3000
email: coolknight@263.net

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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