新增：ByteBuffer与char之间转换的案例

Author: JeffLi1993

src/org/javacore/nio/BufferToText.java

@@ -0,0 +1,101 @@
+package org.javacore.nio;
+
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.charset.Charset;
+
+/*
+ * Copyright [2015] [Jeff Lee]
+ *
+ * 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.
+ */
+
+/**
+ * @author Jeff Lee
+ * @since 2015-10-10 18:58:15
+ *  ByteBuffer与char之间转换的案例
+ */
+public class BufferToText {
+    private static final int BSIZE = 1024; // 1K 字节
+    public static void main(String[] args) throws IOException {
+        // 从文件输出流获取FileChannel
+        FileChannel fc =
+                new FileOutputStream("data.txt").getChannel();
+        // 将带有字节的缓冲区写入该通道
+        fc.write(ByteBuffer.wrap("some data".getBytes()));
+        fc.close();
+
+        // 从文件输入流中获取FileChannel
+        fc = new FileInputStream("data.txt").getChannel();
+        // 分配ByteBuffer的大小 1K
+        ByteBuffer buffer = ByteBuffer.allocate(BSIZE);
+        // 将字节序列通过此通道写入到buffer
+        fc.read(buffer);
+        // 反转缓冲区，为写或者读取做准备
+        buffer.flip();
+        // 作为char缓冲区，并输出 乱码，因为Buffer编码是"UTF-16BE"
+        System.out.println(buffer.asCharBuffer());
+
+        // 重绕此缓冲区
+        buffer.rewind();
+        // 获取文件编码属性
+        String encoding = System.getProperty("file.encoding");
+        // 输出编码及内容
+        System.out.println("编码： " + encoding + " 内容为： "
+                + Charset.forName(encoding).decode(buffer));
+        fc.close();
+
+        // 从文件输出流获取FileChannel
+        fc = new FileOutputStream("data.txt").getChannel();
+        // 将带有字节的缓冲区写入该通道
+        fc.write(ByteBuffer.wrap("some data".getBytes("UTF-16BE")));
+        fc.close();
+
+        // 从文件输入流中获取FileChannel
+        fc = new FileInputStream("data.txt").getChannel();
+        // 清除其缓冲区
+        buffer.clear();
+        // 将字节序列通过该通道写入到buffer
+        fc.read(buffer);
+        // 反转缓冲区，为写或者读取做准备
+        buffer.flip();
+        // 作为char缓冲区，并输出
+        System.out.println(buffer.asCharBuffer());
+        fc.close();
+
+        // 从文件输出流获取FileChannel
+        fc = new FileOutputStream("data.txt").getChannel();
+        // 指定buffer大小为 24字节
+        buffer = ByteBuffer.allocate(24);
+        // 通过char缓冲区，在当前位置写入字符
+        buffer.asCharBuffer().put("some data");
+        // 将带有字节的缓冲区写入该通道
+        fc.write(buffer);
+        fc.close();
+
+        // 从文件输入流中获取FileChannel
+        fc = new FileInputStream("data.txt").getChannel();
+        // 清除缓冲区
+        buffer.clear();
+        // 将字节序列通过文件通道写入到buffer
+        fc.read(buffer);
+        // 反转缓冲区，为读或者写做准备
+        buffer.flip();
+        // 作为char缓冲区，并输出
+        System.out.println(buffer.asCharBuffer());
+    }
+}