TextFileOutputDemo Part 1
public static void main(String[] args)
{
PrintWriter outputStream = null;
try
{
outputStream =
new PrintWriter(new FileOutputStream("out.txt"));
}
catch(FileNotFoundException e)
{
System.out.println("Error opening the file out.txt.");
System.exit(0);
}
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//: c11:IOStreamDemo.java
// Typical I/O stream configurations.
import java.io.*;
public class IOStreamDemo {
// Throw exceptions to console:
public static void main(String[] args)
throws IOException {
// 1. Reading input by lines:
BufferedReader in =
new BufferedReader(
new FileReader("IOStreamDemo.java"));
String s, s2 = new String();
while((s = in.readLine())!= null)
s2 += s + "\n";
in.close();
----------------------------------------
// 1b. Reading standard input:
BufferedReader stdin =
new BufferedReader(
new InputStreamReader(System.in));
System.out.print("Enter a line:");
System.out.println(stdin.readLine());
// 2. Input from memory
StringReader in2 = new StringReader(s2);
int c;
while((c = in2.read()) != -1)
System.out.print((char)c);
--------------------------------------------
// 3. Formatted memory input
try {DataInputStream in3 =new DataInputStream(
new ByteArrayInputStream(s2.getBytes()));
while(true)
System.out.print((char)in3.readByte());
} catch(EOFException e) {
System.err.println("End of stream");
} // 4. File output
try { BufferedReader in4 =
new BufferedReader( new StringReader(s2));
PrintWriter out1 =
new PrintWriter(new BufferedWriter(
new FileWriter("IODemo.out")));
int lineCount = 1;
while((s = in4.readLine()) != null )
out1.println(lineCount++ + ": " + s);
out1.close();
} catch(EOFException e) {
System.err.println("End of stream");
}
------------------------------------------
// 5. Storing & recovering data
try { DataOutputStream out2 =
new DataOutputStream(new BufferedOutputStream(
new FileOutputStream("Data.txt")));
out2.writeDouble(3.14159);
out2.writeChars("That was pi\n");
out2.writeBytes("That was pi\n"); out2.close();
DataInputStream in5 = new DataInputStream(
new BufferedInputStream(
new FileInputStream("Data.txt")));
BufferedReader in5br =
new BufferedReader(new InputStreamReader(in5));
// Must use DataInputStream for data:
System.out.println(in5.readDouble());
// Can now use the "proper" readLine():
System.out.println(in5br.readLine());
System.out.println(in5br.readLine());
} catch(EOFException e) {
System.err.println("End of stream");}
-------------------------------------------------
// 6. Reading/writing random access files
RandomAccessFile rf =
new RandomAccessFile("rtest.dat", "rw");
for(int i = 0; i < 10; i++)
rf.writeDouble(i*1.414);
rf.close();
rf = new RandomAccessFile("rtest.dat", "rw");
rf.seek(5*8);
rf.writeDouble(47.0001);
rf.close();
rf = new RandomAccessFile("rtest.dat", "r");
for(int i = 0; i < 10; i++)
System.out.println(
"Value " + i + ": " +
rf.readDouble());
rf.close();
}
}
--------------------------------------------------
//: c11:GZIPcompress.java
// Uses GZIP compression to compress a file
// whose name is passed on the command line.
import java.io.*;
import java.util.zip.*;
public class GZIPcompress {
// Throw exceptions to console:
public static void main(String[] args)
throws IOException {
BufferedReader in =
new BufferedReader(
new FileReader(args[0]));
BufferedOutputStream out =
new BufferedOutputStream(
new GZIPOutputStream(
new FileOutputStream("test.gz")));
System.out.println("Writing file");
int c;
while((c = in.read()) != -1)
out.write(c);
in.close();
out.close();
System.out.println("Reading file");
BufferedReader in2 =
new BufferedReader(
new InputStreamReader(
new GZIPInputStream(
new FileInputStream("test.gz"))));
String s;
while((s = in2.readLine()) != null)
System.out.println(s);
}
}