From be17633174947ac55865dcc357bf615a7448470c Mon Sep 17 00:00:00 2001 From: chandra Date: Fri, 9 Nov 2018 21:08:02 -0500 Subject: [PATCH] BAEL-2313 Convert String to Byte Array and Reverse in Java --- .../conversion/ByteArrayToStringUnitTest.java | 91 ++++++++++++++ .../conversion/StringToByteArrayUnitTest.java | 119 ++++++++++++++++++ 2 files changed, 210 insertions(+) create mode 100644 java-strings/src/test/java/com/baeldung/string/conversion/ByteArrayToStringUnitTest.java create mode 100644 java-strings/src/test/java/com/baeldung/string/conversion/StringToByteArrayUnitTest.java diff --git a/java-strings/src/test/java/com/baeldung/string/conversion/ByteArrayToStringUnitTest.java b/java-strings/src/test/java/com/baeldung/string/conversion/ByteArrayToStringUnitTest.java new file mode 100644 index 0000000000..cb18d04cc3 --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/conversion/ByteArrayToStringUnitTest.java @@ -0,0 +1,91 @@ +package com.baeldung.string.conversion; + +import static org.junit.jupiter.api.Assertions.assertEquals; +import static org.junit.jupiter.api.Assertions.assertNotNull; + +import java.io.UnsupportedEncodingException; +import java.nio.ByteBuffer; +import java.nio.charset.CharacterCodingException; +import java.nio.charset.Charset; +import java.nio.charset.CharsetDecoder; +import java.nio.charset.CodingErrorAction; +import java.nio.charset.StandardCharsets; + +import org.junit.Test; + +public class ByteArrayToStringUnitTest { + + @Test + public void whenStringConstructorWithDefaultCharset_thenOK() { + final byte[] byteArrray = { 72, 101, 108, 108, 111, 32, 87, 111, 114, + 108, 100, 33 }; + String string = new String(byteArrray); + System.out.println(string); + + assertNotNull(string); + } + + @Test + public void whenStringConstructorWithNamedCharset_thenOK() + throws UnsupportedEncodingException { + final String charsetName = "IBM01140"; + final byte[] byteArrray = { -56, -123, -109, -109, -106, 64, -26, -106, + -103, -109, -124, 90 }; + + String string = new String(byteArrray, charsetName); + + assertEquals("Hello World!", string); + } + + @Test + public void whenStringConstructorWithCharSet_thenOK() { + final Charset charset = Charset.forName("UTF-8"); + final byte[] byteArrray = { 72, 101, 108, 108, 111, 32, 87, 111, 114, + 108, 100, 33 }; + + String string = new String(byteArrray, charset); + + assertEquals("Hello World!", string); + } + + @Test + public void whenStringConstructorWithStandardCharSet_thenOK() { + final Charset charset = StandardCharsets.UTF_16; + + final byte[] byteArrray = { -2, -1, 0, 72, 0, 101, 0, 108, 0, 108, 0, + 111, 0, 32, 0, 87, 0, 111, 0, 114, 0, 108, 0, 100, 0, 33 }; + + String string = new String(byteArrray, charset); + + assertEquals("Hello World!", string); + } + + @Test + public void whenDecodeWithCharset_thenOK() { + byte[] byteArrray = { 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, + 100, 33 }; + final Charset charset = StandardCharsets.UTF_8; + + String string = charset.decode(ByteBuffer.wrap(byteArrray)).toString(); + System.out.println(string); + + assertEquals("Hello World!", string); + } + + @Test + public void whenUsingCharsetDecoder_thenOK() + throws CharacterCodingException { + byte[] byteArrray = { 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, + 100, 33 }; + CharsetDecoder decoder = Charset.forName("UTF-8").newDecoder(); + + decoder.onMalformedInput(CodingErrorAction.IGNORE) + .onUnmappableCharacter(CodingErrorAction.REPLACE) + .replaceWith("?"); + + String string = decoder.decode(ByteBuffer.wrap(byteArrray)).toString(); + + assertEquals("Hello World!", string); + } + +} diff --git a/java-strings/src/test/java/com/baeldung/string/conversion/StringToByteArrayUnitTest.java b/java-strings/src/test/java/com/baeldung/string/conversion/StringToByteArrayUnitTest.java new file mode 100644 index 0000000000..6086e2f60b --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/conversion/StringToByteArrayUnitTest.java @@ -0,0 +1,119 @@ +package com.baeldung.string.conversion; + +import static org.junit.jupiter.api.Assertions.assertArrayEquals; +import static org.junit.jupiter.api.Assertions.assertNotNull; + +import java.io.UnsupportedEncodingException; +import java.nio.CharBuffer; +import java.nio.charset.CharacterCodingException; +import java.nio.charset.Charset; +import java.nio.charset.CharsetEncoder; +import java.nio.charset.CodingErrorAction; +import java.nio.charset.StandardCharsets; +import java.util.Arrays; + +import org.junit.Test; + +public class StringToByteArrayUnitTest { + + @Test + public void whenGetBytesWithDefaultCharset_thenOK() { + final String inputString = "Hello World!"; + final String defaultCharSet = Charset.defaultCharset().displayName(); + + byte[] byteArrray = inputString.getBytes(); + + System.out.printf( + "Using default charset:%s, Input String:%s, Output byte array:%s\n", + defaultCharSet, inputString, Arrays.toString(byteArrray)); + + assertNotNull(byteArrray); + assert (byteArrray.length >= inputString.length()); + } + + @Test + public void whenGetBytesWithNamedCharset_thenOK() + throws UnsupportedEncodingException { + final String inputString = "Hello World!"; + final String charsetName = "IBM01140"; + + byte[] byteArrray = inputString.getBytes("IBM01140"); + + System.out.printf( + "Using named charset:%s, Input String:%s, Output byte array:%s\n", + charsetName, inputString, Arrays.toString(byteArrray)); + + assertArrayEquals(new byte[] { -56, -123, -109, -109, -106, 64, -26, + -106, -103, -109, -124, 90 }, + byteArrray); + } + + @Test + public void whenGetBytesWithCharset_thenOK() { + final String inputString = "Hello World!"; + final Charset charset = Charset.forName("UTF-8"); + + byte[] byteArrray = inputString.getBytes(charset); + + System.out.printf( + "Using Charset:%s, Input String:%s, Output byte array:%s\n", + charset, inputString, Arrays.toString(byteArrray)); + + assertArrayEquals(new byte[] { 72, 101, 108, 108, 111, 32, 87, 111, 114, + 108, 100, 33 }, + byteArrray); + } + + @Test + public void whenGetBytesWithStandardCharset_thenOK() { + final String inputString = "Hello World!"; + final Charset charset = StandardCharsets.UTF_16; + + byte[] byteArrray = inputString.getBytes(charset); + + System.out.printf( + "Using Standard Charset:%s, Input String:%s, Output byte array:%s\n", + charset, inputString, Arrays.toString(byteArrray)); + + assertArrayEquals(new byte[] { -2, -1, 0, 72, 0, 101, 0, 108, 0, 108, 0, + 111, 0, 32, 0, 87, 0, 111, 0, 114, 0, 108, 0, 100, 0, 33 }, + byteArrray); + } + + @Test + public void whenEncodeWithCharset_thenOK() { + final String inputString = "Hello World!"; + final Charset charset = StandardCharsets.UTF_8; + + byte[] byteArrray = charset.encode(inputString).array(); + + System.out.printf( + "Using encode with Charset:%s, Input String:%s, Output byte array:%s\n", + charset, inputString, Arrays.toString(byteArrray)); + + assertArrayEquals(new byte[] { 72, 101, 108, 108, 111, 32, 87, 111, 114, + 108, 100, 33, 0 }, + byteArrray); + } + + @Test + public void whenUsingCharsetEncoder_thenOK() + throws CharacterCodingException { + final String inputString = "Hello World!"; + CharsetEncoder encoder = Charset.forName("UTF-8").newEncoder(); + encoder.onMalformedInput(CodingErrorAction.IGNORE) + .onUnmappableCharacter(CodingErrorAction.REPLACE) + .replaceWith(new byte[] { 0 }); + + byte[] byteArrray = encoder.encode(CharBuffer.wrap(inputString)).array(); + + System.out.printf( + "Using encode with CharsetEncoder:%s, Input String:%s, Output byte array:%s\n", + encoder, inputString, Arrays.toString(byteArrray)); + + assertArrayEquals(new byte[] { 72, 101, 108, 108, 111, 32, 87, 111, 114, + 108, 100, 33, 0 }, + byteArrray); + } + +}