无法通过applet代码从sql数据库中检索数据 [英] failed to retrieve data from sql database through applet code
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问题描述
import java.sql.*;
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
/*
<HTML>
<BODY>
<HEAD>
<applet code="Sem3ResultsApplet" width=1000 height=1000>
</applet>
</HEAD>
</BODY>
br mode="hold" />*/
public class Sem3ResultsApplet extends Applet implements ItemListener,ActionListener,MouseListener
{
Label LIDNo;
TextField IDNo;
Button GO;
String Name;
int ENGLISH;
int IILANG;
int MATHEMATICS;
int STATISTIC;
int COMPUTERSCIENCE;
int MATHEMATICSPR;
int STATISTICSPR;
int COMPUTERSCIENCEPR;
int TOTAL;
int TPOSITION;
int GrandTOTAL;
int GPOSITION;
float PERCENTAGE;
public void init()
{
// LABEL
LIDNo = new Label("Enter Your IDNo :",Label.LEFT);
//TEXT FIELD
IDNo = new TextField(8);
// BUTTON
GO = new Button("GO");
// Adding items
add(LIDNo);
add(IDNo);
add(GO);
// Adding Listeners
IDNo.addActionListener(this);
GO.addActionListener(this);
addMouseListener(this);
}
// Provide empty implementations for the other MouseListener methods.
public void mouseClicked(MouseEvent me) {
}
public void mouseEntered(MouseEvent me) {
}
public void mouseExited(MouseEvent me) {
}
public void mouseReleased(MouseEvent me) {
}
public void mousePressed(MouseEvent me) {
}
public void actionPerformed(ActionEvent ae)
{
String str = ae.getActionCommand();
if (ae.getSource() == GO)
{
try
{
Connection conn = DriverManager.getConnection("jdbc:odbc:FirstData");
Statement stmt = conn.createStatement();
String strSelect = "select * from Sem3Results where IDNo ="+IDNo.getText();
ResultSet rset = stmt.executeQuery(strSelect);
while(rset.next())
{
int IDNo = rset.getInt("IDNo");
String Name = rset.getString("Name");
int ENGLISH = rset.getInt("ENGLISH");
int IILANG = rset.getInt("IILANG");
int MATHEMATICS = rset.getInt("MATHEMATICS");
int STATISTIC = rset.getInt("STATISTIC");
int COMPUTERSCIENCE = rset.getInt("COMPUTERSCIENCE");
int MATHEMATICSPR = rset.getInt("MATHEMATICSPR");
int STATISTICSPR = rset.getInt("STATISTICSPR");
int COMPUTERSCIENCEPR = rset.getInt("COMPUTERSCIENCEPR");
int TOTAL = rset.getInt("TOTAL");
int TPOSITION = rset.getInt("TPOSITION");
int GrandTOTAL = rset.getInt("GrandTOTAL");
int GPOSITION = rset.getInt("GPOSITION");
float PERCENTAGE = rset.getFloat("PERCENTAGE");
break;
}
repaint();
}
catch(SQLException e)
{
e.printStackTrace();
}
}
}
public void itemStateChanged(ItemEvent ie) {
repaint();
}
public void paint(Graphics g)
{
g.drawString("IDNo :12141146"+IDNo.getText(),100,100);
g.drawString("Name :"+Name,100,120);
g.drawString("ENGLISH :"+ENGLISH,100,140);
g.drawString("IILANG :"+IILANG,100,160);
g.drawString("MATHEMATICS :"+MATHEMATICS,100,180);
g.drawString("STATISTICS :"+STATISTIC,100,200);
g.drawString("COMPUTERSCIENCE :"+COMPUTERSCIENCE,100,220);
g.drawString("MATHEMATICSPR :"+MATHEMATICSPR,100,240);
g.drawString("STATISTICSPR :"+STATISTICSPR,100,260);
g.drawString("COMPUTERSCIENCEPR :"+COMPUTERSCIENCEPR,100,280);
g.drawString("TOTAL :"+TOTAL,100,300);
g.drawString("TPOSITION :"+TPOSITION,100,320);
g.drawString("GrandTOTAL :"+GrandTOTAL,100,340);
g.drawString("GPOSITION :"+GPOSITION,100,360);
g.drawString("PERCENTAGE :"+PERCENTAGE,100,380);
}
}
推荐答案
谢谢Prasad Khandekar
连接路径是正确的。
因为当我使用主类时它能够显示输出并且能够检索数据。
不能使用不从sql数据库检索数据的applet
代码如下
// sampel java prg使用mysql- table（s）名称显示来自数据库Students的记录：Sem3Results
import java.sql。* ; // 1
import java.io.BufferedReader; // 2
import java.io.IOException; // 3
import java.io.InputStreamReader; // 4
// 5
公共课Sem3Results // 6
{// 7
// 8
public static void main（String [] args）// 9
{// 10
// 11
System.out.println（输入您的IDNo）; // 12
尝试// 13
{// 14
// 15
BufferedReader bufferRead = new BufferedReader（new InputStreamReader（System.in））; // 16
String s = bufferRead.readLine（）; // 17
连接conn = DriverManager.getConnection（jdbc：odbc：FirstData）; // 18
语句stmt = conn.createStatement（）; // 19
String strSelect =select * from Sem3Results，其中IDNo =+ s; // 20
// 22
// 23
ResultSet rset = stmt.executeQuery（strSelect）; // 24
// 25
// 26
// 27
while（rset.next（ ））// 28
{// 29
// 30
int IDNo = rset.getInt（IDNo）; // 31
String Name = rset.getString（Name）; // 32
int ENGLISH = rset.getInt（ENGLISH）; // 33
int IILANG = rset.getInt（IILANG）; // 34
int MATHEMATICS = rset.getInt（MATHEMATICS）; // 35
int STATISTIC = rset.getInt（STATISTIC）; // 36
int COMPUTERSCIENCE = rset.getInt（COMPUTERSCIENCE）; // 37
int MATHEMATICSPR = rset.getInt（MATHEMATICSPR）; // 38
int STATISTICSPR = rset.getInt（STATISTICSPR）; // 39
int COMPUTERSCIENCEPR = rset.getInt（COMPUTERSCIENCEPR）; // 40
int TOTAL = rset.getInt（TOTAL）; // 41
int TPOSITION = rset.getInt（TPOSITION）; // 42
int GrandTOTAL = rset.getInt（GrandTOTAL）; // 43
int GPOSITION = rset.getInt（GPOSITION）; // 44
float PERCENTAGE = rset.getFloat（PERCENTAGE）; // 45
// 46
System.out.println（IDNo：12141146+ IDNo）; // 47
System.out.println（名称：+名称）; // 48
System.out.println（英语：+ ENGLISH）; // 49
System.out.println（II语言：+ IILANG）; // 50
System.out.println（数学：+数学）; // 51
System.out.println（Statistics：+ STATISTIC）; // 52
System.out.println（计算机科学：+计算机科学）; // 53
System.out.println（数学公关：+ MATHEMATICSPR）; // 54
System.out.println（统计PR：+ STATISTICSPR）; // 55
System.out.println（计算机科学公关：+ COMPUTERSCIENCEPR）; // 56
System.out.println（总计：+ TOTAL）; // 57
System.out.println（Rank：+ TPOSITION）; // 58
System.out.println（Grand Total：+ GrandTOTAL）; // 59
System.out.println（Rank：+ GPOSITION）; // 60
System.out.println（百分比：+ PERCENTAGE）; // 61
休息; // 62
} // 63
// 64
// 65
} // 66
catch（SQLException e）// 67
{// 68
e.printStackTrace（）; // 69
} // 70
catch（IOException e）// 71
{// 72
e.printStackTrace（）; // 73
} // 74
} // 75
} // 76
Thank you Prasad Khandekar
Connection path is correct.
because when I used with main class it able to show output and it able to retrieve data.
It is not working with applet which does not retrieving data from sql database
the code is below
//sampel java prg to display record from the database "Students" using mysql- table(s) name: "Sem3Results"
import java.sql.*; // 1
import java.io.BufferedReader; // 2
import java.io.IOException; // 3
import java.io.InputStreamReader; // 4
// 5
public class Sem3Results // 6
{ // 7
// 8
public static void main(String[] args) // 9
{ // 10
// 11
System.out.println("Enter Your IDNo"); // 12
try // 13
{ // 14
// 15
BufferedReader bufferRead = new BufferedReader(new InputStreamReader(System.in)); // 16
String s = bufferRead.readLine(); // 17
Connection conn = DriverManager.getConnection("jdbc:odbc:FirstData"); // 18
Statement stmt = conn.createStatement(); // 19
String strSelect = "select * from Sem3Results where IDNo ="+s; // 20
// 22
// 23
ResultSet rset = stmt.executeQuery(strSelect); // 24
// 25
// 26
// 27
while(rset.next()) // 28
{ // 29
// 30
int IDNo= rset.getInt("IDNo"); // 31
String Name= rset.getString("Name"); // 32
int ENGLISH= rset.getInt("ENGLISH"); // 33
int IILANG= rset.getInt("IILANG"); // 34
int MATHEMATICS= rset.getInt("MATHEMATICS"); // 35
int STATISTIC= rset.getInt("STATISTIC"); // 36
int COMPUTERSCIENCE= rset.getInt("COMPUTERSCIENCE"); // 37
int MATHEMATICSPR= rset.getInt("MATHEMATICSPR"); // 38
int STATISTICSPR= rset.getInt("STATISTICSPR"); // 39
int COMPUTERSCIENCEPR= rset.getInt("COMPUTERSCIENCEPR"); // 40
int TOTAL= rset.getInt("TOTAL"); // 41
int TPOSITION= rset.getInt("TPOSITION"); // 42
int GrandTOTAL= rset.getInt("GrandTOTAL"); // 43
int GPOSITION= rset.getInt("GPOSITION"); // 44
float PERCENTAGE = rset.getFloat("PERCENTAGE"); // 45
// 46
System.out.println("IDNo :12141146"+IDNo); // 47
System.out.println("Name :"+Name); // 48
System.out.println("English :" + ENGLISH); // 49
System.out.println("II Language :" + IILANG); // 50
System.out.println("Mathematics :" + MATHEMATICS); // 51
System.out.println("Statistics :"+ STATISTIC); // 52
System.out.println("Computer Science :"+COMPUTERSCIENCE); // 53
System.out.println("Mathematics PR :"+MATHEMATICSPR); // 54
System.out.println("Statistics PR :"+STATISTICSPR); // 55
System.out.println("Computer Science PR :"+COMPUTERSCIENCEPR); // 56
System.out.println("Total :"+TOTAL); // 57
System.out.println("Rank :"+TPOSITION); // 58
System.out.println("Grand Total :"+GrandTOTAL); // 59
System.out.println("Rank :"+GPOSITION); // 60
System.out.println("Percentage :"+PERCENTAGE); // 61
break; // 62
} // 63
// 64
// 65
} // 66
catch(SQLException e) // 67
{ // 68
e.printStackTrace(); // 69
} // 70
catch(IOException e) // 71
{ // 72
e.printStackTrace(); // 73
} // 74
} // 75
} // 76
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