Java Tutorial/JSP/File Save Load
Версия от 17:44, 31 мая 2010; (обсуждение)
Содержание
Index of Files
<%@ page import="java.io.*" %>
<HTML>
<HEAD>
<TITLE>Index of Files</TITLE>
</HEAD>
<BODY>
<H1>Index of Files</H1>
Click a file to open/download it...
<%
String file = application.getRealPath("/");
File file1 = new File(file);
String [] fileNames = file1.list();
File [] fileObjects= file1.listFiles();
%>
<UL>
<%
for (int i = 0; i < fileObjects.length; i++) {
if(!fileObjects[i].isDirectory()){
%>
<LI>
(<%= Long.toString(fileObjects[i].length()) %> bytes long)
<%
}
}
%>
</UL>
</BODY>
</HTML>
Read file
<%@ page import="java.io.*" %>
<HTML>
<HEAD>
<TITLE>The file</TITLE>
</HEAD>
<BODY>
<H1>The Guest Book</H1>
Here are the current entries in the file:
<BR>
<BR>
<%
String file = application.getRealPath("/") + "basic.jsp";
File fileObject = new File(file);
char data[] = new char[(int) fileObject.length()];
FileReader filereader = new FileReader(file);
int charsread = filereader.read(data);
out.println(new String(data, 0 , charsread));
filereader.close();
%>
</BODY>
</HTML>
Reading Binary Data
<%@ page import="java.io.*" %>
<HTML>
<HEAD>
<TITLE>Reading Binary Data</TITLE>
</HEAD>
<BODY>
<H1>Reading Binary Data</H1>
This page reads binary data from a file.
<BR>
Read this data:
<BR>
<BR>
<%
String file = application.getRealPath("/") + "test.dat";
double data[] = {1.234, 2.345, 3.456, 4.567};
FileOutputStream fileoutputstream = new FileOutputStream(file);
ObjectOutputStream objectStream = new ObjectOutputStream(fileoutputstream );
for (int i = 0; i < data.length; i++) {
objectStream.writeDouble(data[i]);
}
objectStream.close();
FileInputStream fileinputstream = new FileInputStream(file);
ObjectInputStream inputobjectStream = new ObjectInputStream(fileinputstream);
for(int i = 0; i < 4; i++){
double d = inputobjectStream.readDouble();
out.println(d);
}
objectStream.close();
%>
</BODY>
</HTML>
Save Form Input to File using JSP
index.jsp
<HTML>
<HEAD>
<TITLE>Please Sign My Guest Book!</TITLE>
</HEAD>
<BODY>
<CENTER>
<H1>Please Sign My Guest Book!</H1>
<FORM ACTION="basic.jsp" METHOD="POST">
Your name:
<INPUT TYPE="TEXT" NAME="TEXT1">
<BR>
<BR>
<BR>
Your comments:
<BR>
<TEXTAREA NAME="TEXTAREA1" ROWS="5" COLS="50"></TEXTAREA>
<BR>
<INPUT TYPE="SUBMIT" VALUE="Submit"><INPUT TYPE="RESET" VALUE="Reset">
</FORM>
</CENTER>
</BODY>
</HTML>
Writing Binary Data
<%@ page import="java.io.*" %>
<HTML>
<HEAD>
<TITLE>Writing Binary Data</TITLE>
</HEAD>
<BODY>
<H1>Writing Binary Data</H1>
This page writes binary data to a file.
<BR>
<%
byte data[] = {1, 2, 3, 4};
String file = application.getRealPath("/") + "test.dat";
FileOutputStream fileoutputstream = new FileOutputStream(file);
for (int i = 0; i < data.length; i++) {
fileoutputstream.write(data[i]);
}
fileoutputstream.close();
%>
Four byte values were written to a file byte by byte.
</BODY>
</HTML>
