Go语言常用的打log方式详解

package main

import (
    "log"
    "bytes"
    "fmt"
    "os"
"github.com/astaxie/beego/logs"
)

func main() {

    //1.日志写入一段缓存里
    var buf bytes.Buffer
    logger := log.New(&buf, "logger: ", log.Llongfile)//三个参数对应输出对象，前缀，文件名然后整合成前缀
    logger.Print("Hello, log file!") //实际log信息
    fmt.Println(&buf)

    //2.日志写入一段文件里,执行完刷新工程，会有文件debug.log打开来看
    fileName := "debug.log"  //在工程路径下和src同级，也可以写绝对路径，不过要注意转义符
    logFile,err  := os.Create(fileName)  //创建该文件，返回句柄
    defer logFile.Close()      //确保文件在该函数执行完以后关闭
    if err != nil {  
        log.Fatalln("open file error !")  
    }  

    //库里的log包不存在级别，只有Print，Fatal，Panic三种，想要7种级别，可以用syslog包或者框架
    debugLog := log.New(logFile,"",log.Llongfile)  
    debugLog.Print("找到一个低级bug,低级别的日志报告，执行debug记录后继续执行")
    debugLog.Fatal("发现一个严重bug，日志已记录，程序在此终止")
    debugLog.Panic("哎呀，我没有被执行，好惨")

    //3.使用beego框架的log包进行log处理 ，对应7种级别
    logInstance:=logs.GetLogger()
    logInstance.Println("this is a message of http")
    //an official log.Logger with prefix ORM
    logs.GetLogger("ORM").Println("this is a message of orm")
    logs.Debug("my book is bought in the year of ", 2016)
    logs.Info("this %s cat is %v years old", "yellow", 3)
    logs.Warn("json is a type of kv like", map[string]int{"key": 2016})
    logs.Error(1024, "is a very", "good game")
    logs.Critical("oh,crash")
    logs.Notice("fuck")
    logs.Alert("alert")
    logs.Emergency("emergency")

}

package main

import (
    "os"
    "log"
)



func main() {
    file, err := os.OpenFile("./testLog/test.log",  os.O_CREATE | os.O_WRONLY | os.O_APPEND,os.ModePerm)
    if err != nil {
        log.Fatalln(err)
    }
    logger := log.New(file, "", log.LstdFlags|log.Llongfile)
    logger.Println("日志1.")
    logger.Println("日志23")
}