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2010-06-01T05:19:22Z

1 версия

в 17:44, 31 мая 2010

2010-05-31T17:44:27Z

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== FileReader ==

<OL><LI>The FileReader class is a subclass of InputStreamReader</LI><LI>The FileReader class is a convenient class to read characters from a file.</LI><LI>The FileReader class uses an encoding other than the default one.</LI></OL>
<p>To construct a FileReader object:</p>



<source lang="java">
public FileReader (File file)
public FileReader (FileDescriptor fileDescriptor)
public FileReader (String filePath)</source>



== Loading text from a file ==



<source lang="java">
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
public class Main {
public static void main(String[] argv) throws Exception {
File f = new File("C:\\test.txt");
FileReader fr = new FileReader(f);
BufferedReader br = new BufferedReader(fr);
StringBuffer sb = new StringBuffer();
String eachLine = br.readLine();
while (eachLine != null) {
sb.append(eachLine);
sb.append("\n");
eachLine = br.readLine();
}
System.out.println(sb.toString());
}
}</source>



== Read file upside down ==



<source lang="java">
import java.io.File;
import java.io.FileReader;
public class Main {
public static void main(String[] args) throws Exception {
File f = new File("hello.txt");
FileReader fr = new FileReader(f);
char[] c = new char[(int) f.length()];
char[] cnew = new char[(int) f.length()];
StringBuffer sbuf = new StringBuffer();
fr.read(c, 0, (int) f.length());
int len = (int) f.length();
for (int i = 0, j = len - 1; i < len; i++, j--) {
cnew[i] = c[j];
sbuf.append(cnew[i]);
}
System.out.println(sbuf.toString());
fr.close();
}
}</source>



== Read the file one buffer at a time ==



<source lang="java">
import java.io.FileReader;
public class Main {
public static void main(String[] argv) throws Exception {
FileReader fr = new FileReader("text.txt");
int count;
char chrs[] = new char[80];
do {
count = fr.read(chrs);
for (int i = 0; i < count; i++)
System.out.print(chrs[i]);
} while (count != -1);
}
}</source>



== Use a FileReader to display a text file. ==



<source lang="java">
import java.io.FileReader;
public class Main {
public static void main(String[] argv) throws Exception {
FileReader fr = new FileReader("text.txt");
int ch;
do {
ch = fr.read();
if (ch != -1)
System.out.println((char) ch);
} while (ch != -1);
fr.close();
}
}</source>



== Wrap FileReader with BufferedReader ==



<source lang="java">
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
public class SourceReader {
public static void main(String[] arguments) {
try {
FileReader file = new FileReader("SourceReader.java");
BufferedReader buff = new BufferedReader(file);
boolean eof = false;
while (!eof) {
String line = buff.readLine();
if (line == null)
eof = true;
else
System.out.println(line);
}
buff.close();
} catch (IOException e) {
System.out.println("Error - " + e.toString());
}
}
}</source>

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Java Tutorial/File/FileReader - История изменений

Admin: 1 версия

в 17:44, 31 мая 2010