Adapts to either Java 8's {@link java.util.Base64} class or Apache + * Commons Codec's {@link org.apache.commons.codec.binary.Base64} class. + * With neither Java 8 nor Commons Codec present, encode/decode calls + * will fail with an IllegalStateException. + * + * @author Juergen Hoeller + * @since 4.1 + * @see java.util.Base64 + * @see org.apache.commons.codec.binary.Base64 + */ +public abstract class Base64Utils { + + private static final Charset DEFAULT_CHARSET = Charset.forName("UTF-8"); + + + private static final Base64Delegate delegate; + + static { + Base64Delegate delegateToUse = null; + // JDK 8's java.util.Base64 class present? + if (ClassUtils.isPresent("java.util.Base64", Base64Utils.class.getClassLoader())) { + delegateToUse = new JdkBase64Delegate(); + } + // Apache Commons Codec present on the classpath? + else if (ClassUtils.isPresent("org.apache.commons.codec.binary.Base64", Base64Utils.class.getClassLoader())) { + delegateToUse = new CommonsCodecBase64Delegate(); + } + delegate = delegateToUse; + } + + /** + * Assert that Byte64 encoding is actually supported. + * @throws IllegalStateException if neither Java 8 nor Apache Commons Codec is present + */ + private static void assertSupported() { + Assert.state(delegate != null, "Neither Java 8 nor Apache Commons Codec found - Base64 encoding not supported"); + } + + + /** + * Base64-encode the given byte array. + * @param src the original byte array (may be {@code null}) + * @return the encoded byte array (or {@code null} if the input was {@code null}) + * @throws IllegalStateException if Base64 encoding is not supported, + * i.e. neither Java 8 nor Apache Commons Codec is present at runtime + */ + public static byte[] encode(byte[] src) { + assertSupported(); + return delegate.encode(src); + } + + /** + * Base64-encode the given byte array to a String. + * @param src the original byte array (may be {@code null}) + * @return the encoded byte array as a UTF-8 String + * (or {@code null} if the input was {@code null}) + * @throws IllegalStateException if Base64 encoding is not supported, + * i.e. neither Java 8 nor Apache Commons Codec is present at runtime + */ + public static String encodeToString(byte[] src) { + assertSupported(); + if (src == null) { + return null; + } + if (src.length == 0) { + return ""; + } + return new String(delegate.encode(src), DEFAULT_CHARSET); + } + + /** + * Base64-decode the given byte array. + * @param src the encoded byte array (may be {@code null}) + * @return the original byte array (or {@code null} if the input was {@code null}) + * @throws IllegalStateException if Base64 encoding is not supported, + * i.e. neither Java 8 nor Apache Commons Codec is present at runtime + */ + public static byte[] decode(byte[] src) { + assertSupported(); + return delegate.decode(src); + } + + /** + * Base64-decode the given byte array from an UTF-8 String. + * @param src the encoded UTF-8 String (may be {@code null}) + * @return the original byte array (or {@code null} if the input was {@code null}) + * @throws IllegalStateException if Base64 encoding is not supported, + * i.e. neither Java 8 nor Apache Commons Codec is present at runtime + */ + public static byte[] decodeFromString(String src) { + assertSupported(); + if (src == null) { + return null; + } + if (src.length() == 0) { + return new byte[0]; + } + return delegate.decode(src.getBytes(DEFAULT_CHARSET)); + } + + + private interface Base64Delegate { + + byte[] encode(byte[] src); + + byte[] decode(byte[] src); + } + + + private static class JdkBase64Delegate implements Base64Delegate { + + public byte[] encode(byte[] src) { + if (src == null || src.length == 0) { + return src; + } + return Base64.getEncoder().encode(src); + } + + public byte[] decode(byte[] src) { + if (src == null || src.length == 0) { + return src; + } + return Base64.getDecoder().decode(src); + } + } + + + private static class CommonsCodecBase64Delegate implements Base64Delegate { + + private final org.apache.commons.codec.binary.Base64 base64 = new org.apache.commons.codec.binary.Base64(); + + public byte[] encode(byte[] src) { + return this.base64.encode(src); + } + + public byte[] decode(byte[] src) { + return this.base64.decode(src); + } + } + +} diff --git a/spring-web/src/main/java/org/springframework/http/converter/json/GsonBase64ByteArrayJsonTypeAdapter.java b/spring-web/src/main/java/org/springframework/http/converter/json/GsonBase64ByteArrayJsonTypeAdapter.java deleted file mode 100644 index d3c342797b..0000000000 --- a/spring-web/src/main/java/org/springframework/http/converter/json/GsonBase64ByteArrayJsonTypeAdapter.java +++ /dev/null @@ -1,61 +0,0 @@ -/* - * Copyright 2002-2014 the original author or authors. - * - * Licensed under the Apache License, Version 2.0 (the "License"); - * you may not use this file except in compliance with the License. - * You may obtain a copy of the License at - * - * http://www.apache.org/licenses/LICENSE-2.0 - * - * Unless required by applicable law or agreed to in writing, software - * distributed under the License is distributed on an "AS IS" BASIS, - * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. - * See the License for the specific language governing permissions and - * limitations under the License. - */ - -package org.springframework.http.converter.json; - -import java.lang.reflect.Type; -import java.nio.charset.Charset; - -import com.google.gson.GsonBuilder; -import com.google.gson.JsonDeserializationContext; -import com.google.gson.JsonDeserializer; -import com.google.gson.JsonElement; -import com.google.gson.JsonPrimitive; -import com.google.gson.JsonSerializationContext; -import com.google.gson.JsonSerializer; -import com.google.gson.TypeAdapter; -import org.apache.commons.codec.binary.Base64; - -/** - * Custom Gson {@link TypeAdapter} for serialization and deserialization - * of {@code byte[]} values to/from Base64-encoded Strings. - * - *
By default, Gson converts byte arrays to JSON arrays. This type adapter
- * needs to be specifically registered to read/write Base64-encoded byte arrays.
- *
- * @author Roy Clarkson
- * @since 4.1
- * @see GsonBuilder#registerTypeHierarchyAdapter(Class, Object)
- */
-class GsonBase64ByteArrayJsonTypeAdapter implements JsonSerializer A custom {@link com.google.gson.TypeAdapter} will be registered via
+ * {@link GsonBuilder#registerTypeHierarchyAdapter(Class, Object)} which
+ * serializes a {@code byte[]} property to and from a Base64-encoded String
+ * instead of a JSON array.
+ * NOTE: Use of this option requires the presence of the
+ * Apache Commons Codec library on the classpath when running on Java 6 or 7.
+ * On Java 8, the standard {@link java.util.Base64} facility is used instead.
+ */
+ public static GsonBuilder gsonBuilderWithBase64EncodedByteArrays() {
+ // Assert that Base64 support is available, as long we're not on Java 8+
+ Base64Utils.encode(null);
+
+ // Now, construct a pre-configured GsonBuilder...
+ GsonBuilder builder = new GsonBuilder();
+ builder.registerTypeHierarchyAdapter(byte[].class, new Base64TypeAdapter());
+ return builder;
+ }
+
+
+ private static class Base64TypeAdapter implements JsonSerializer When set to {@code true}, a custom {@link com.google.gson.TypeAdapter} will be
+ * registered via {@link GsonBuilder#registerTypeHierarchyAdapter(Class, Object)}
+ * which serializes a {@code byte[]} property to and from a Base64-encoded String
+ * instead of a JSON array.
+ * NOTE: Use of this option requires the presence of the
+ * Apache Commons Codec library on the classpath when running on Java 6 or 7.
+ * On Java 8, the standard {@link java.util.Base64} facility is used instead.
+ * @see GsonBuilderUtils#gsonBuilderWithBase64EncodedByteArrays()
*/
- public void setGsonBuilder(GsonBuilder gsonBuilder) {
- this.gsonBuilder = gsonBuilder;
+ public void setBase64EncodeByteArrays(boolean base64EncodeByteArrays) {
+ this.base64EncodeByteArrays = base64EncodeByteArrays;
}
/**
@@ -108,49 +108,24 @@ public class GsonFactoryBean implements FactoryBean When set to {@code true} a custom {@link com.google.gson.TypeAdapter} is
- * registered via {@link GsonBuilder#registerTypeHierarchyAdapter(Class, Object)}
- * that serializes a {@code byte[]} property to and from a Base64-encoded String
- * instead of a JSON array.
- * NOTE: Use of this option requires the presence of the
- * Apache Commons Codec library on the classpath.
- * @see GsonBase64ByteArrayJsonTypeAdapter
- */
- public void setBase64EncodeByteArrays(boolean base64EncodeByteArrays) {
- this.base64EncodeByteArrays = base64EncodeByteArrays;
- }
-
@Override
public void afterPropertiesSet() {
- if (this.gsonBuilder == null) {
- this.gsonBuilder = new GsonBuilder();
- }
+ GsonBuilder builder = (this.base64EncodeByteArrays ?
+ GsonBuilderUtils.gsonBuilderWithBase64EncodedByteArrays() : new GsonBuilder());
if (this.serializeNulls) {
- this.gsonBuilder.serializeNulls();
+ builder.serializeNulls();
}
if (this.prettyPrinting) {
- this.gsonBuilder.setPrettyPrinting();
+ builder.setPrettyPrinting();
}
if (this.disableHtmlEscaping) {
- this.gsonBuilder.disableHtmlEscaping();
+ builder.disableHtmlEscaping();
}
if (this.dateFormatPattern != null) {
- this.gsonBuilder.setDateFormat(this.dateFormatPattern);
+ builder.setDateFormat(this.dateFormatPattern);
}
- if (this.base64EncodeByteArrays) {
- if (commonsCodecPresent) {
- this.gsonBuilder.registerTypeHierarchyAdapter(byte[].class, new GsonBase64ByteArrayJsonTypeAdapter());
- }
- else {
- throw new IllegalStateException(
- "Apache Commons Codec is not available on the classpath - cannot enable Gson Base64 encoding");
- }
- }
- this.gson = this.gsonBuilder.create();
+ this.gson = builder.create();
}