java复制文件，本程序中是.txt文件，也可是其他文件。指定路径可自己修改，需要复制的文件必须存在，否则只会新建空文件。程序中注解已表明路径与文件名-java copy files, this program is. txt files, but other files. Specified path can modify their own, need to copy the file must exist, otherwise it will create an empty file. A