Java完成JSP在Servelt中銜接Oracle數據庫的辦法。本站提示廣大學習愛好者：（Java完成JSP在Servelt中銜接Oracle數據庫的辦法）文章只能為提供參考，不一定能成為您想要的結果。以下是Java完成JSP在Servelt中銜接Oracle數據庫的辦法正文
本文實例講述了Java完成JSP應用Servelt銜接Oracle數據庫的辦法。為了完成在Servlet 中銜接數據庫，必需編寫Servlet 的類法式。將Servlet 類法式放到WEB 辦事器的servlets 或許classes 目次上面，為挪用Servlet，須要創立發送Servlet 要求的HTML 文檔。本例經由過程(Driver)Class.forName(driverName).newInstance()辦法來完成加載驅動法式，樹立與數據庫銜接。
詳細法式代碼為：
1．Database 類繼續了HttpServlet 類，共有兩個辦法：doGet()和displayResult()，代碼以下：
public class Database extends HttpServlet
{
public void doGet()；
public void displayResult(ResultSet results,PrintWriter out);
}
2．在doGet()辦法中樹立與數據庫的銜接並履行查詢：
public void doGet()
{
HttpServletRequest request,
HttpServletResponse response
}
throws ServletException, IOException
{
PrintWriter out;
String title = "Simple Servlet connecting to Oracle DB";
response.setContentType("text/html;charset=GB2312");
out = response.getWriter();
out.println("<HTML><HEAD><TITLE>");
out.println(title);
out.println("</TITLE></HEAD><BODY>");
out.println("<H1>" + title + "</H1>");
out.println("<P>This is output from SimpleServlet.");
String driverName = "oracle.jdbc.driver.OracleDriver";
Driver d;
Connection con;
Statement stmt;
ResultSet results;
try
{
d = (Driver)Class.forName(driverName).newInstance();
con = DiverManager.getConnection("jdbc:oracle:thin:ndb/[email protected]:1521:PC6");
stmt = con.createStatement();
String sqlstr = "select * from data";
results = stmt.executeQuery(sqlstr);
displayResult(results,out);
stmt.close();
con.close();
}
catch (Exception e)
{
out.println("error: " + e.toString());
}
out.println("</BODY></HTML>");
out.close();
}
3．DisplayResult()辦法顯示查詢成果:
public void displayResult(ResultSet results,PrintWriter out)
{
StringBuffer buf = new StringBuffer();
String temp;
try
{
ResultSetMetaData rsmd = results.getMetaData();
int numCols = rsmd.getColumnCount();
int i, rowcount = 0;
for (i=1; i <= numCols; i++)
{
if (i > 1) buf.append(",");
buf.append(rsmd.getColumnLabel(i));
}
buf.append("");
while (results.next() && rowcount < 100)
{
for (i=1; i <= numCols; i++)
{
if (i > 1) buf.append(",");
buf.append((results.getString(i)));
}
buf.append("<br>");
rowcount++;
}
out.println("<br>");
out.println(buf.toString());
results.close();
}
catch (Exception e)
{
out.println("error: " + e.toString());
return;
}
}
4．由於法式應用了JDBC 類、servlet 類和應用掌握台輸入，所以須要引入以下的包：
import java.sql.*; import java.io.*; import javax.servlet.*; import javax.servlet.http.*;
5．編譯Database.java，發生Database.class 文件，將Database.class 放到WEB 辦事器的servlets 目次下，本例采取Java Web Server 作為WEB 辦事器。設置裝備擺設好WEB 辦事器，添加database.class，指命名稱為database。
6．編寫挪用Servlet 的database.html 文件。代碼以下：
<html> <head> <title>Jsp應用Servlet銜接數據庫</title> </head> <body> <center> <form action="/servlet/database" method="get"> <input name="action" type="submit" value="銜接數據庫"> </form> </center> </body> </html>
