fix code

hutool-core/src/main/java/cn/hutool/core/io/resource/CharSequenceResource.java

@@ -85,7 +85,7 @@ public class CharSequenceResource implements Resource, Serializable {
 
 	@Override
 	public byte[] readBytes() throws IORuntimeException {
-		return this.data.toString().getBytes(this.charset);
+		return StrUtil.bytes(this.data, this.charset);
 	}
 
 }

hutool-http/src/main/java/cn/hutool/http/client/body/StringBody.java

@@ -0,0 +1,35 @@
+package cn.hutool.http.client.body;
+
+import cn.hutool.core.io.resource.StringResource;
+import cn.hutool.http.HttpUtil;
+
+import java.nio.charset.Charset;
+
+/**
+ * String类型的body，一般用于Rest请求的请求体，如JSON或XML
+ *
+ * @author looly
+ */
+public class StringBody extends ResourceBody {
+
+	/**
+	 * 构造，根据body内容类型，自动识别Content-Type
+	 *
+	 * @param body    Body内容
+	 * @param charset 自定义编码
+	 */
+	public StringBody(final String body, final Charset charset) {
+		this(body, HttpUtil.getContentTypeByRequestBody(body), charset);
+	}
+
+	/**
+	 * 构造
+	 *
+	 * @param body        Body内容
+	 * @param contentType 自定义Content-Type
+	 * @param charset     自定义编码
+	 */
+	public StringBody(final String body, final String contentType, final Charset charset) {
+		super(new StringResource(body, contentType, charset));
+	}
+}