J2SE - String、InputStream、OutputStream 互轉

一、String 轉 InputStream

InputStream is = new ByteArrayInputStream(str.getBytes());
           

InputStream is = IOUtils.toInputStream(str,Charset.forName("utf-8"));
           

二、InputStream 轉 String

StringBuilder sb = new StringBuilder();
	String line;

	BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));
	while ((line = br.readLine()) != null) {
	    sb.append(line);
	}
	
	String drstr = sb.toString();
           

ByteArrayOutputStream baos = new ByteArrayOutputStream();
	byte[] buff = new byte[1024];
	int length;
	
	while ((length = iputStream.read(buff)) != -1) {
	    baos.write(buff, 0, length);
	}
	
	String dostr = baos.toString(StandardCharsets.UTF_8.name());
           

StringWriter sw = new StringWriter();
	IOUtils.copy(iputStream, sw, StandardCharsets.UTF_8);
	String dwstr = sw.toString();
           

String distr = IOUtils.toString(iputStream, StandardCharsets.UTF_8);
           

三、InputStream 轉 OutputStream

ByteArrayOutputStream baos = new ByteArrayOutputStream();
	byte[] buff = new byte[1024];
	int length;
	while ((length = iputStream.read(buff)) != -1) {
		baos.write(buffer, 0, length);
	}
           

四、OutputStream 轉 InputStream

ByteArrayOutputStream baos = new ByteArrayOutputStream();
	ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
           

五、OutputStream 轉 String

ByteArrayOutputStream baos = new ByteArrayOutputStream();
	ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
	String dostr = bais.toString();
           

六、String 轉 OutputStream

ByteArrayInputStream bais = new ByteArrayInputStream(str.getBytes());
	ByteArrayOutputStream baos = new ByteArrayOutputStream();
     
	byte[] buffer = new byte[1024];
	int length;
	 
	while ((length = bais.read(buffer)) != -1) {
		baos.write(buffer, 0, length);
	}
           

附、IOUtils

<dependency>
		<groupId>commons-io</groupId>
		<artifactId>commons-io</artifactId>
		<version>2.5</version>
	</dependency>