Java InputStream Read by Charset toString(InputStream input, Charset charset)

Description

Retrieve the content from the input stream as a string using the specified charset.

License

Open Source License

Parameter

Parameter	Description
input	the input stream to retrieve
charset	the chartset used in the conversion

Return

the content from the input stream

Declaration

public static String toString(InputStream input, Charset charset) 

Method Source Code

//package com.java2s;

import java.io.ByteArrayOutputStream;
import java.io.Closeable;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.Charset;

public class Main {
    public static final int EOF = -1;
    static final int DefaultBufferSize = 4096;

    /**//from ww  w .j a v  a2 s  .  com
     * Retrieve the content from the input stream as a string.
     *
     * @param input the input stream to retrieve
     * @return the content from the input stream
     */
    public static String toString(InputStream input) {
        return toString(input, Charset.forName("UTF-8"));
    }

    /**
     * Retrieve the content from the input stream as a string using the specified
     * charset. Note that the method does <em>NOT</em> close the given input stream,
     * and the caller should close the input stream.
     *
     * @param input the input stream to retrieve
     * @param charset the chartset used in the conversion
     * @return the content from the input stream
     */
    public static String toString(InputStream input, Charset charset) {
        ByteArrayOutputStream output = new ByteArrayOutputStream();
        copy(input, output);
        String result = new String(output.toByteArray(), charset);
        closeSilently(output);
        return result;
    }

    /**
     * Copy the content from the input stream into the output stream. Note that the method does
     * <em>NOT</em> close the given input stream and output stream, the caller should close the
     * given streams.
     *
     * @param input the content source
     * @param output the copy target
     * @return the copied bytes; {@value #EOF} means error occurs
     */
    public static long copy(InputStream input, OutputStream output) {
        return copy(input, output, optimalSizedBuffer());
    }

    /**
     * Copy the content from the input stream into the output stream. Note that the method does
     * <em>NOT</em> close the given input stream and output stream, the caller should close the
     * given streams.
     *
     * @param input the content source
     * @param output the copy target
     * @param buffer the buffer to be used during copy
     * @return the copied bytes; {@value #EOF} means error occurs
     */
    public static long copy(InputStream input, OutputStream output, byte[] buffer) {
        if (input == null || output == null || buffer == null) {
            return EOF;
        }

        int read = 0;
        long copied = 0;
        try {
            while ((read = input.read(buffer)) != EOF) {
                output.write(buffer, 0, read);
                copied += read;
            }
            output.flush();
        } catch (IOException e) {
            copied = EOF;
        }
        return copied;
    }

    /**
     * Close the given {@link Closeable} resource (e.g., {@link java.io.InputStream InputStream},
     * {@link java.io.OutputStream OutputStream}, {@link java.io.Reader Reader}, or
     * {@link java.io.Writer Writer}) without the exception handling. Note that this
     * method should ONLY be used in final cause, this method is not the way to avoid
     * writing exception handling.
     *
     * @param closeable the resource to be closed.
     */
    public static void closeSilently(Closeable closeable) {
        if (closeable != null) {
            try {
                closeable.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * Create an optimal sized buffer, usually the size is 4 KB for most platforms.
     * 
     * @return the optimal sized buffer
     */
    public static byte[] optimalSizedBuffer() {
        return new byte[DefaultBufferSize];
    }
}

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