做进口产品的网站好,it外包公司怎么接项目,城市门户网站怎样盈利,安徽360优化目录 问题解决 常见的打开模式 问题解决 出现于调用os.Open来打开的文件进行写操作时报的错#xff0c;原因在于Open函数#xff1a; func Open(name string) (*File,error) {return OpenFile(name, O_RDONLY, 0) } Open调用了OpenFile#xff0c;而OpenFile默认以只读… 目录 问题解决 常见的打开模式 问题解决 出现于调用os.Open来打开的文件进行写操作时报的错原因在于Open函数 func Open(name string) (*File,error) {return OpenFile(name, O_RDONLY, 0) } Open调用了OpenFile而OpenFile默认以只读方式来打开文件参数2为O_RDONLY因此这时候基于Open要想写就不行了 正确操作携带的打开模式根据实际情况来 writerFile, err : os.OpenFile(writerFilePath, os.O_CREATE|os.O_APPEND|os.O_WRONLY, os.ModeAppend) // 读写O_RDWR   仅写os.O_WRONLY 常见的打开模式 os.O_CREATE表示文件无则创建 os.O_APPEND写入时有则追加 os.O_WRONLY只写模式(write-only) O_RDONLY只读模式(read-only) O_RDWR读写模式(read-write) O_EXCL与 O_CREATE 一起用构成一个新建文件的功能它要求文件必须不存在(used with O_CREATE, file must not exist) O_SYNC同步方式打开即不使用缓存直接写入硬盘 O_TRUNC打开并清空文件 源码中给出的打开方式有 // Flags to OpenFile wrapping those of the underlying system. Not all // flags may be implemented on a given system. const (// Exactly one of O_RDONLY, O_WRONLY, or O_RDWR must be specified.O_RDONLY int syscall.O_RDONLY // open the file read-only.O_WRONLY int syscall.O_WRONLY // open the file write-only.O_RDWR   int syscall.O_RDWR   // open the file read-write.// The remaining values may be ored in to control behavior.O_APPEND int syscall.O_APPEND // append data to the file when writing.O_CREATE int syscall.O_CREAT  // create a new file if none exists.O_EXCL   int syscall.O_EXCL   // used with O_CREATE, file must not exist.O_SYNC   int syscall.O_SYNC   // open for synchronous I/O.O_TRUNC  int syscall.O_TRUNC  // truncate regular writable file when opened. ) os.ModeAppend为第三个参数参数3为FileMode // The defined file mode bits are the most significant bits of the FileMode. // The nine least-significant bits are the standard Unix rwxrwxrwx permissions. // The values of these bits should be considered part of the public API and // may be used in wire protocols or disk representations: they must not be // changed, although new bits might be added. const (// The single letters are the abbreviations// used by the String methods formatting.ModeDir         fs.ModeDir        // d: is a directoryModeAppend     fs.ModeAppend     // a: append-onlyModeExclusive   fs.ModeExclusive  // l: exclusive useModeTemporary   fs.ModeTemporary  // T: temporary file; Plan 9 onlyModeSymlink     fs.ModeSymlink    // L: symbolic linkModeDevice     fs.ModeDevice     // D: device fileModeNamedPipe   fs.ModeNamedPipe  // p: named pipe (FIFO)ModeSocket     fs.ModeSocket     // S: Unix domain socketModeSetuid     fs.ModeSetuid     // u: setuidModeSetgid     fs.ModeSetgid     // g: setgidModeCharDevice fs.ModeCharDevice // c: Unix character device, when ModeDevice is setModeSticky     fs.ModeSticky     // t: stickyModeIrregular   fs.ModeIrregular  // ?: non-regular file; nothing else is known about this file// Mask for the type bits. For regular files, none will be set.ModeType fs.ModeTypeModePerm fs.ModePerm // Unix permission bits, 0o777 )