FEAT StreamUtils.toInputStream & StreamUtils.toString

src/main/java/de/nclazz/commons/io/StreamUtils.java

@@ -2,8 +2,10 @@ package de.nclazz.commons.io;
 
 import de.nclazz.commons.util.StringUtils;
 import lombok.NonNull;
+import lombok.SneakyThrows;
 
 import java.io.*;
+import java.nio.charset.Charset;
 import java.security.MessageDigest;
 
 public abstract class StreamUtils {
@@ -63,5 +65,47 @@ public abstract class StreamUtils {
         }
     }
 
+    /**
+     * Converts given string to an InputStream.
+     * @param string to convert
+     * @return new InputStream
+     */
+    public static InputStream toInputStream(@NonNull String string, Charset charset) {
+        charset = charset != null ? charset : Charset.defaultCharset();
+        byte[] bytes = string.getBytes(charset);
+        return new ByteArrayInputStream(bytes);
+    }
+
+    /**
+     * @see #toInputStream(String, Charset) 
+     * @param string to read
+     * @return new InputStream
+     */
+    public static InputStream toInputStream(@NonNull String string) {
+        return toInputStream(string, Charset.defaultCharset());
+    }
+
+    /**
+     * Reads the given InputStream and converts it to a String.
+     * The stream does not close after this operation.
+     * @param stream to read
+     * @param charset of the String
+     * @return new String
+     */
+    @SneakyThrows
+    public static String toString(@NonNull InputStream stream, Charset charset) {
+        charset = charset != null ? charset : Charset.defaultCharset();
+        byte[] bytes = inputStreamToByteArray(stream);
+        return new String(bytes, charset);
+    }
+
+    /**
+     * @see #toString(InputStream, Charset)
+     * @param stream to read
+     * @return new String
+     */
+    public static String toString(@NonNull InputStream stream) {
+        return toString(stream, Charset.defaultCharset());
+    }
 
 }

src/main/java/de/nclazz/commons/util/StringUtils.java

@@ -3,6 +3,7 @@ package de.nclazz.commons.util;
 import lombok.NonNull;
 import lombok.SneakyThrows;
 
+import java.io.InputStream;
 import java.security.MessageDigest;
 
 public abstract class StringUtils {

src/test/java/de/nclazz/commons/io/StreamUtilsTests.java

@@ -8,6 +8,7 @@ import java.io.IOException;
 import java.io.InputStream;
 import java.util.Arrays;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class StreamUtilsTests {
@@ -37,4 +38,16 @@ public class StreamUtilsTests {
         assertTrue(Arrays.equals(alphabetBytes, bytes));
     }
 
+    @Test
+    void stringToInputStreamRoundTrip() throws IOException {
+        String testString = "Hello World!";
+        InputStream stream = StreamUtils.toInputStream(testString);
+        String backString = StreamUtils.toString(stream);
+
+        stream.close();
+
+        assertEquals(testString, backString);
+    }
+
+
 }