String 、InputStream、Reader 之间的转换

1、String –> InputStream

InputStrem is = new ByteArrayInputStream(str.getBytes());
or
ByteArrayInputStream stream = new ByteArrayInputStream(str.getBytes());

 2、InputStream–>String

InputStream input;
StringBuffer out = new StringBuffer();
byte[] b = new byte[4096];
for (int n; (n = input.read(b)) != -1;) {
    out.append(new String(b, 0, n));
}
out.toString();

3、Reader –>String

BufferedReader in = new BufferedReader(new InputStreamReader(is));
StringBuffer buffer = new StringBuffer();
String line = " ";
while ((line = in.readLine()) != null){
    buffer.append(line);
}
return buffer.toString();

4、String–>Reader

Reader reader = new StringReader("hhhhhh");