add Headers

src/main/java/com/qiniu/http/Headers.java

@@ -0,0 +1,99 @@
+package com.qiniu.http;
+
+import com.qiniu.util.StringMap;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+public class Headers {
+    // 代理了部分 okhttp3.Headers 方法 //
+    okhttp3.Headers innerHeaders;
+
+    Headers(Builder builder) {
+        innerHeaders = builder.innerBuilder.build();
+    }
+
+    private Headers() {
+
+    }
+
+    /**
+     * Returns the last value corresponding to the specified field, or null.
+     */
+    public String get(String name) {
+        return innerHeaders.get(name);
+    }
+
+    /**
+     * Returns an immutable case-insensitive set of header names.
+     */
+    public Set<String> names() {
+        return innerHeaders.names();
+    }
+
+    /**
+     * Returns an immutable list of the header values for {@code name}.
+     */
+    public List<String> values(String name) {
+        return innerHeaders.values(name);
+    }
+
+    public Builder newBuilder() {
+        Builder builder = new Builder();
+        builder.innerBuilder = innerHeaders.newBuilder();
+        return builder;
+    }
+
+    public static Headers of(Map<String, String> headers) {
+        Headers inner = new Headers();
+        inner.innerHeaders = okhttp3.Headers.of(headers);
+        return inner;
+    }
+
+    public static Headers of(StringMap headers) {
+        final Builder builder = new Builder();
+        if (headers == null) {
+            return builder.build();
+        }
+        ;
+        headers.forEach(new StringMap.Consumer() {
+            @Override
+            public void accept(String key, Object value) {
+                if (null != value) {
+                    builder.add(key, value.toString());
+                }
+            }
+        });
+        return builder.build();
+    }
+
+
+    public static final class Builder {
+        // 代理了部分 okhttp3.Headers.Builder 方法 //
+        private okhttp3.Headers.Builder innerBuilder;
+
+        public Builder() {
+            innerBuilder = new okhttp3.Headers.Builder();
+        }
+
+        public Builder add(String name, String value) {
+            innerBuilder.add(name, value);
+            return this;
+        }
+
+        public Builder addAll(Headers headers) {
+            innerBuilder.addAll(headers.innerHeaders);
+            return this;
+        }
+
+        public Builder set(String name, String value) {
+            innerBuilder.set(name, value);
+            return this;
+        }
+
+        public Headers build() {
+            return new Headers(this);
+        }
+    }
+}