Closeable:

package java.io;import java.io.IOException;public interface Closeable {    /**     * Closes this stream and releases any system resources associated     * with it. If the stream is already closed then invoking this      * method has no effect.      */    public void close() throws IOException;}

Readable:

package java.lang;import java.io.IOException;public interface Readable {    /**     * Attempts to read characters into the specified character buffer.     * The buffer is used as a repository of characters as-is: the only     * changes made are the results of a put operation. No flipping or     * rewinding of the buffer is performed.     */    public int read(java.nio.CharBuffer cb) throws IOException;}

Flushable:

package java.io;import java.io.IOException;public interface Flushable {    /**     * Flushes this stream by writing any buffered output to the underlying stream.     */    void flush() throws IOException;}

Appendable:

package java.lang;import java.io.IOException;public interface Appendable {    /**     * Appends the specified character sequence to this Appendable.     * @return  A reference to this Appendable     */    Appendable append(CharSequence csq) throws IOException;    /**     * Appends a subsequence of the specified character sequence to this Appendable.     * @return  A reference to this Appendable     */    Appendable append(CharSequence csq, int start, int end) throws IOException;    /**     * Appends the specified character to this Appendable.     * @return  A reference to this Appendable     */    Appendable append(char c) throws IOException;}

 转自：https://blog.csdn.net/jjavaboy/article/details/43093435