在浏览器中执行jdbc小程序 [英] Execute jdbc applet in browser
问题描述
import java.sql.*;
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
/*
<applet code="A0" width=250 height=200>
</applet>
*/
public class A0 extends Applet implements ActionListener,ItemListener
{
String msg="";
Button view,delete,create,edit,reapp,exit;
TextField M_head;
int x,i,ans=0,flag;
public void init()
{
setLayout(new FlowLayout(FlowLayout.CENTER,50,3));
view = new Button("view");
delete = new Button("delete");
create = new Button("create");
edit = new Button("edit");
reapp = new Button("reapp");
exit= new Button("exit");
M_head = new TextField(15);
add(view);
add(delete);
add(create);
System.out.println("vikram");
add(edit);
add(reapp);
add(exit);
System.out.println("phaneendra");
add(M_head);
view.addActionListener(this);
delete.addActionListener(this);
create.addActionListener(this);
edit.addActionListener(this);
reapp.addActionListener(this);
exit.addActionListener(this);
M_head.addActionListener(this);
}
public void actionPerformed(ActionEvent ae)
{
String str=ae.getActionCommand();
if(str.equals("view"))
{msg ="1";}
if(str.equals("delete"))
{msg ="2";}
if(str.equals("create"))
{msg ="3";}
if(str.equals("edit"))
{msg ="4";}
if(str.equals("reapp"))
{msg ="5";}
if(str.equals("exit"))
{msg ="6";}
if(msg=="3")
{
try{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
//String filename = "E:/vikram/conn/new/db/north.mdb";
String filename = "./db/north.mdb";
String database = "jdbc:odbc:Driver={Microsoft Access Driver (*.mdb)};DBQ=";
//String url ="jdbc:odbc:Driver={Microsoft Access Driver (*.mdb)};DBQ=D:\\cheminDeMaBaseEtNomdeLaBdd";
database+=filename.trim();
String head = M_head.getText();
String head1 = head.trim();
Connection con = DriverManager.getConnection(database,"","");
Statement doo = con.createStatement();
//String vi ="create table head1 (Reapporder integer, Amount integer)";
String vi="insert into head1 values(1,2);";
boolean i=false;
i=doo.execute(vi);
if(i)
M_head.setText("Failed to insert");
else
M_head.setText("record inserted");
}
catch(Exception err)
{
System.out.println("Error :"+err);
}
}
}
public void itemStateChanged(ItemEvent ie)
{
repaint();
}
public void paint(Graphics g)
{
g.drawString(msg,70,200); //No use
g.drawString("ANSWER=",6,200); // No use
}
}
这是A0.txt
grant {
permission java.lang.RuntimePermission
"accessClassInPackage.sun.jdbc.odbc";
permission java.util.PropertyPermission
"file.encoding", "read";
};
A0.html 文件
<html>
<head>
</head>
<body>
<applet code=A0 width=250 height=200></applet>
</body>
</html>
这段代码在Appletviewer命令中执行，但不在任何浏览器中执行
This code is executed in Appletviewer command, but not in any browser
推荐答案
正如其他人所说，你真的不想这样做.
As commented by others, you really don't want to do this.
只需在服务器端创建一个 webservice(可以是一个普通的 vanilla servlet)并使用 java.net.URLConnection 在小程序中.
Just create a webservice in the server side (which can be a plain vanilla servlet) and make use of java.net.URLConnection in the applet.
基本 Servlet 示例:
Basic Servlet example:
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String action = request.getParameter("action"); // Or request.getPathInfo() whatever you want.
String result = someDAO.doAction(action);
response.getWriter().write(result);
}
基本小程序示例:
URL url = new URL("http://example.com/databaseservlet?action=someaction");
URLConnection connection = url.openConnection();
InputStream result = connection.getInputStream(); // Important. This actually fires the request!
但是要小心 SQL 注入.不要将原始 SQL 查询作为请求参数或路径信息传递，并使用 PreparedStatement 一直在 DAO 代码中.
Be careful with SQL injections however. Do in no way pass raw SQL queries as request parameters or pathinfo and use PreparedStatement all the time in the DAO code.
作为响应数据格式，您可以使用普通字符串(如示例中所示)或 XML 字符串 或 JSON 字符串 甚至一个完整的 Java 对象在序列化的帮助下.
As response data format you can use a plain vanilla String (as given in example) or a XML string or a JSON string or maybe even a fullworthy Java object with a little help of Serialization.
这篇关于在浏览器中执行jdbc小程序的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
