java.io.Closeable

package java.io;

import java.io.IOException;

/**
 * A {@code Closeable} is a source or destination of data that can be closed.
 * The close method is invoked to release resources that the object is
 * holding (such as open files).
 *
 * @since 1.5
 */
public interface Closeable extends AutoCloseable {

    /**
     * Closes this stream and releases any system resources associated
     * with it. If the stream is already closed then invoking this
     * method has no effect.
     *
     * <p> As noted in {@link AutoCloseable#close()}, cases where the
     * close may fail require careful attention. It is strongly advised
     * to relinquish the underlying resources and to internally
     * <em>mark</em> the {@code Closeable} as closed, prior to throwing
     * the {@code IOException}.
     *
     * @throws IOException if an I/O error occurs
     */
    public void close() throws IOException;
}

根据官方的注释，大概翻译是：Closeable 是能够关闭的数据源或目标。调用 close 方法可释放对象保存的资源（如打开文件）。

关闭此流并释放与此流关联的全部系统资源。若是已经关闭该流，则调用此方法无效.