public static int copy(final Reader input, final Writer output) throws IOException {
		final long count = copyLarge(input, output);
		if (count > Integer.MAX_VALUE) {
			return -1;
		}
		return (int) count;
	}
Copies chars from a <code>Reader</code> to a <code>Writer</code>.
<p>
This method buffers the input internally, so there is no need to use a
<code>BufferedReader</code>.
<p>
Large streams (over 2GB) will return a chars copied value of <code>-1</code> after
the copy has completed since the correct number of chars cannot be returned as an
int. For large streams use the <code>copyLarge(Reader, Writer)</code> method.
@param input the <code>Reader</code> to read from
@param output the <code>Writer</code> to write to
@return the number of characters copied, or -1 if &gt; Integer.MAX_VALUE
@throws NullPointerException if the input or output is null
@throws IOException if an I/O error occurs
@since 1.1
spring-cloud-alibaba-starters/spring-cloud-alibaba-commons/src/main/java/com/alibaba/cloud/commons/io/IOUtils.java