The tutorial show you many ways to convert an InputStream to String, including using Java 8 Stream.
Contents
I. Ways to convert an InputStream to a String
1. Using IOUtils
1 2 3 | import org.apache.commons.io.IOUtils; String result1 = IOUtils.toString(inputStream, "UTF-8"); |
2. Using CharStreams
1 2 3 4 | import com.google.common.base.Charsets; import com.google.common.io.CharStreams; String result2 = CharStreams.toString(new InputStreamReader(inputStream, Charsets.UTF_8)); |
3. Using Scanner
1 2 3 4 5 6 7 8 9 10 11 | import java.util.Scanner; Scanner s = null; try { s = new Scanner(inputStream); s.useDelimiter("\\Z"); String result3 = s.hasNext() ? s.next() : ""; } finally { s.close(); } |
4. Using StringWriter
1 2 3 4 5 | import java.io.StringWriter; StringWriter writer = new StringWriter(); IOUtils.copy(inputStream, writer, "UTF-8"); String result4 = writer.toString(); |
5. Using ByteArrayOutputStream
1 2 3 4 5 6 7 8 9 | import java.io.ByteArrayOutputStream; ByteArrayOutputStream bArrOutStrem = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int length; while ((length = inputStream.read(buffer)) != -1) { bArrOutStrem.write(buffer, 0, length); } String result5 = bArrOutStrem.toString("UTF-8"); |
6. Using BufferedInputStream
1 2 3 4 5 6 7 8 9 10 11 | import java.io.BufferedInputStream; import java.io.ByteArrayOutputStream; BufferedInputStream bis = new BufferedInputStream(inputStream); ByteArrayOutputStream buf = new ByteArrayOutputStream(); int ris = bis.read(); while (ris != -1) { buf.write((byte) ris); ris = bis.read(); } String result6 = buf.toString(); |
7. Using Java 8 Stream
The method: java.io.BufferedReader.lines() returns a Stream.
1 | String result7 = new BufferedReader(new InputStreamReader(inputStream)).lines().collect(Collectors.joining("\n")); |
II. Source code
This code is compiled successfully with Java 1.8.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 | package com.javasampleapproach.instream2string; import java.io.BufferedInputStream; import java.io.BufferedReader; import java.io.ByteArrayInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.StringWriter; import java.util.Scanner; import java.util.stream.Collectors; import org.apache.commons.io.IOUtils; import com.google.common.base.Charsets; import com.google.common.io.CharStreams; public class MainApp { static String myString = "Java Sample Approach"; public static void main(String[] args) throws IOException { // using IOUtils.toString InputStream is = new ByteArrayInputStream(myString.getBytes("UTF-8")); String result1 = IOUtils.toString(is, "UTF-8"); System.out.println("using IOUtils.toString >> " + result1); // using CharStreams is = new ByteArrayInputStream(myString.getBytes("UTF-8")); String result2 = CharStreams.toString(new InputStreamReader(is, Charsets.UTF_8)); System.out.println("using CharStreams >> " + result2); // using Scanner is = new ByteArrayInputStream(myString.getBytes("UTF-8")); Scanner s = null; try { s = new Scanner(is); s.useDelimiter("\\Z"); String result3 = s.hasNext() ? s.next() : ""; System.out.println("using Scanner >> " + result3); } finally { s.close(); } // using StringWriter is = new ByteArrayInputStream(myString.getBytes("UTF-8")); StringWriter writer = new StringWriter(); IOUtils.copy(is, writer, "UTF-8"); String result4 = writer.toString(); System.out.println("using StringWriter >> " + result4); // using ByteArrayOutputStream is = new ByteArrayInputStream(myString.getBytes("UTF-8")); ByteArrayOutputStream bArrOutStrem = new ByteArrayOutputStream(); byte[] buffer = new byte[1024]; int length; while ((length = is.read(buffer)) != -1) { bArrOutStrem.write(buffer, 0, length); } String result5 = bArrOutStrem.toString("UTF-8"); System.out.println("using ByteArrayOutputStream >> " + result5); // using BufferedInputStream is = new ByteArrayInputStream(myString.getBytes("UTF-8")); BufferedInputStream bis = new BufferedInputStream(is); ByteArrayOutputStream buf = new ByteArrayOutputStream(); int ris = bis.read(); while (ris != -1) { buf.write((byte) ris); ris = bis.read(); } String result6 = buf.toString(); System.out.println("using BufferedInputStream >> " + result6); // using Java 8 Stream is = new ByteArrayInputStream(myString.getBytes("UTF-8")); String result7 = new BufferedReader(new InputStreamReader(is)).lines().collect(Collectors.joining("\n")); System.out.println("using Java 8 Stream >> " + result7); } } |
Run code above, the result in console window:
1 2 3 4 5 6 7 | using IOUtils.toString >> Java Sample Approach using CharStreams >> Java Sample Approach using Scanner >> Java Sample Approach using StringWriter >> Java Sample Approach using ByteArrayOutputStream >> Java Sample Approach using BufferedInputStream >> Java Sample Approach using Java 8 Stream >> Java Sample Approach |
Last updated on June 4, 2017.