golang读取文件的常用方法

红太狼 2022-06-02 03:48 261阅读 0赞

//按字节读取，将整个文件读取到缓冲区buffer
    func test1() {
    	file,err := os.Open("filetoread.txt")
    	if err != nil {
    		log.Fatal(err)
    	}
    
    	defer file.Close()
    	fileinfo,err := file.Stat()
    	if err != nil {
    		log.Fatal(err)
    	}
    
    	fileSize := fileinfo.Size()
    	buffer := make([]byte,fileSize)
    
    	bytesread,err := file.Read(buffer)
    	if err != nil {
    		log.Fatal(err)
    	}
    
    	fmt.Println("bytes read:",bytesread)
    	fmt.Println("bytestream to string:",string(buffer))
    }
    
    //每次读取固定字节
    //问题容易出现乱码，因为中文和中文符号不占一个字符
    func test2() {
    	const BufferSize = 100
    	file,err := os.Open("filetoread.txt")
    	if err != nil {
    		log.Fatal(err)
    	}
    	defer file.Close()
    
    	buffer := make([]byte,BufferSize)
    
    	for {
    		bytesread,err := file.Read(buffer)
    		if err != nil {
    			if err != io.EOF {
    				log.Println(err)
    			}
    			break
    		}
    
    		fmt.Println("bytes read:",bytesread)
    		fmt.Println("bytestream to string:",string(buffer[:bytesread]))
    	}
    }
    
    
    //逐行读取
    func test3() {
    	file ,err := os.Open("filetoread.txt")
    	if err != nil {
    		log.Fatal(err)
    	}
    	defer file.Close()
    
    	scanner := bufio.NewScanner(file)
    	scanner.Split(bufio.ScanLines)
    	/*
    		ScanLines (默认)
    		ScanWords
    		ScanRunes (遍历UTF-8字符非常有用)
    		ScanBytes
    	*/
    
    	//是否有下一行
    	for scanner.Scan() {
    		fmt.Println("read string:",scanner.Text())
    	}
    
    }
    
    //使用ioutil读取文件的所有内容
    func test4() {
    	bytes,err := ioutil.ReadFile("filetoread.txt")
    	if err != nil {
    		log.Fatal(err)
    	}
    	fmt.Println("total bytes read：",len(bytes))
    	fmt.Println("string read:",string(bytes))
    }

参考地址:Go 中不同的文件读取方式 http://kgrz.io/reading-files-in-go-an-overview.html