java文件的读写的定义，读写的几种方法，以及文件相关操作-java file read and write the definition of several methods of reading and writing, and file related operations

This code implement semaphore, using 2 proccess, which first is write string consanant values to txt-file, second read txt-file-This code implement semaphore, using 2 proccess, which first is write string consanant values to txt-file, second read t