Copy the contents of the given Reader into a String. - Java java.io

Description

Copy the contents of the given Reader into a String.

Demo Code

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.StringWriter;
import java.io.Writer;

public class Main{
    public static final int BUFFER_SIZE = 4096;
    /**//from  w w w.j a  v  a  2s . c  o m
     * Copy the contents of the given Reader into a String. Closes the reader
     * when done.
     * 
     * @param in
     *            the reader to copy from
     * @return the String that has been copied to
     * @throws IOException
     *             in case of I/O errors
     */
    public static String copyToString(final Reader in) throws IOException {
        final StringWriter out = new StringWriter();
        copy(in, out);
        return out.toString();
    }
    /**
     * Returns the contents of the given File as a String.
     * <p>
     * Consider using {@link FileUtils#read(File)} instead if any
     * {@link IOException}s would be unrecoverable.
     * 
     * @param file
     *            the file to read from
     * @return the contents
     * @throws IOException
     *             in case of I/O errors
     */
    public static String copyToString(final File file) throws IOException {
        return copyToString(new BufferedReader(new FileReader(file)));
    }
    /**
     * Copy the contents of the given input File to the given output File.
     * 
     * @param in
     *            the file to copy from
     * @param out
     *            the file to copy to
     * @return the number of bytes copied
     * @throws IOException
     *             in case of I/O errors
     */
    public static int copy(final File in, final File out)
            throws IOException {
        Assert.notNull(in, "No input File specified");
        Assert.notNull(out, "No output File specified");
        return copy(new BufferedInputStream(new FileInputStream(in)),
                new BufferedOutputStream(new FileOutputStream(out)));
    }
    /**
     * Copy the contents of the given byte array to the given output File.
     * 
     * @param bytes
     *            the byte array to copy from
     * @param file
     *            the file to copy to
     * @throws IOException
     *             in case of I/O errors
     */
    public static void copy(final byte[] bytes, final File file)
            throws IOException {
        Assert.notNull(bytes, "No input byte array specified");
        Assert.notNull(file, "No output File specified");
        final ByteArrayInputStream in = new ByteArrayInputStream(bytes);
        final OutputStream out = new BufferedOutputStream(
                new FileOutputStream(file));
        copy(in, out);
    }
    /**
     * Copy the contents of the given InputStream to the given OutputStream.
     * Closes both streams when done.
     * 
     * @param in
     *            the stream to copy from
     * @param out
     *            the stream to copy to
     * @return the number of bytes copied
     * @throws IOException
     *             in case of I/O errors
     */
    public static int copy(InputStream in, OutputStream out)
            throws IOException {
        Assert.notNull(in, "No InputStream specified");
        Assert.notNull(out, "No OutputStream specified");
        if (!(in instanceof BufferedInputStream)) {
            in = new BufferedInputStream(in);
        }
        if (!(out instanceof BufferedOutputStream)) {
            out = new BufferedOutputStream(out);
        }
        try {
            int byteCount = 0;
            final byte[] buffer = new byte[BUFFER_SIZE];
            int bytesRead = -1;
            while ((bytesRead = in.read(buffer)) != -1) {
                out.write(buffer, 0, bytesRead);
                byteCount += bytesRead;
            }
            out.flush();
            return byteCount;
        } finally {
            IOUtils.closeQuietly(in, out);
        }
    }
    /**
     * Copy the contents of the given byte array to the given OutputStream.
     * Closes the stream when done.
     * 
     * @param bytes
     *            the byte array to copy from
     * @param out
     *            the OutputStream to copy to
     * @throws IOException
     *             in case of I/O errors
     */
    public static void copy(final byte[] bytes, final OutputStream out)
            throws IOException {
        Assert.notNull(bytes, "No input byte array specified");
        Assert.notNull(out, "No OutputStream specified");
        try {
            out.write(bytes);
        } finally {
            IOUtils.closeQuietly(out);
        }
    }
    /**
     * Copy the contents of the given Reader to the given Writer. Closes both
     * when done.
     * 
     * @param in
     *            the Reader to copy from
     * @param out
     *            the Writer to copy to
     * @return the number of characters copied
     * @throws IOException
     *             in case of I/O errors
     */
    public static int copy(Reader in, Writer out) throws IOException {
        Assert.notNull(in, "No Reader specified");
        Assert.notNull(out, "No Writer specified");
        if (!(in instanceof BufferedReader)) {
            in = new BufferedReader(in);
        }
        if (!(out instanceof BufferedWriter)) {
            out = new BufferedWriter(out);
        }
        try {
            int byteCount = 0;
            final char[] buffer = new char[BUFFER_SIZE];
            int bytesRead = -1;
            while ((bytesRead = in.read(buffer)) != -1) {
                out.write(buffer, 0, bytesRead);
                byteCount += bytesRead;
            }
            out.flush();
            return byteCount;
        } finally {
            IOUtils.closeQuietly(in, out);
        }
    }
    /**
     * Copy the contents of the given String to the given output Writer. Closes
     * the writer when done.
     * 
     * @param in
     *            the String to copy from
     * @param out
     *            the Writer to copy to
     * @throws IOException
     *             in case of I/O errors
     */
    public static void copy(final String in, Writer out) throws IOException {
        Assert.notNull(in, "No input String specified");
        Assert.notNull(out, "No Writer specified");
        if (!(out instanceof BufferedWriter)) {
            out = new BufferedWriter(out);
        }
        try {
            out.write(in);
        } finally {
            IOUtils.closeQuietly(out);
        }
    }
}

• Previous
• Next

Related Tutorials

• read From File via FileReader
• Reads a file and converts each line to String[] Array
• copy Reader To String
• Copy the contents of the given Reader to the given Writer.
• Write a string to a file using FileWriter