Java Tutorial/JSP/File Save Load
Содержание
Index of Files
<source lang="java">
<%@ page import="java.io.*" %> <HTML>
<HEAD> <TITLE>Index of Files</TITLE> </HEAD> <BODY>
Index of Files
Click a file to open/download it... <% String file = application.getRealPath("/"); File file1 = new File(file); String [] fileNames = file1.list(); File [] fileObjects= file1.listFiles(); %>
-
<%
for (int i = 0; i < fileObjects.length; i++) {
if(!fileObjects[i].isDirectory()){
%>
- (<%= Long.toString(fileObjects[i].length()) %> bytes long) <% } } %>
</BODY>
</HTML></source>
Read file
<source lang="java">
<%@ page import="java.io.*" %> <HTML>
<HEAD> <TITLE>The file</TITLE> </HEAD> <BODY>
The Guest Book
Here are the current entries in the file:
<% 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></source>
Reading Binary Data
<source lang="java">
<%@ page import="java.io.*" %> <HTML>
<HEAD> <TITLE>Reading Binary Data</TITLE> </HEAD> <BODY>
Reading Binary Data
This page reads binary data from a file.
Read this data:
<% 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></source>
Save Form Input to File using JSP
index.jsp
<source lang="java">
<HTML>
<HEAD> <TITLE>Please Sign My Guest Book!</TITLE> </HEAD> <BODY>
Please Sign My Guest Book!
<FORM ACTION="basic.jsp" METHOD="POST"> Your name: <INPUT TYPE="TEXT" NAME="TEXT1">
Your comments:
<TEXTAREA NAME="TEXTAREA1" ROWS="5" COLS="50"></TEXTAREA>
<INPUT TYPE="SUBMIT" VALUE="Submit"><INPUT TYPE="RESET" VALUE="Reset"> </FORM>
</BODY>
</HTML></source>
Writing Binary Data
<source lang="java">
<%@ page import="java.io.*" %> <HTML>
<HEAD> <TITLE>Writing Binary Data</TITLE> </HEAD> <BODY>
Writing Binary Data
This page writes binary data to a file.
<% 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></source>