From 9ac394294a92c57419cb1d12e7098293cfaf01c4 Mon Sep 17 00:00:00 2001
From: yumaojun03 <719118794@qq.com>
Date: Sun, 1 Mar 2026 09:53:57 +0800
Subject: [PATCH] =?UTF-8?q?```=20feat(log):=20=E5=AE=9E=E7=8E=B0=E6=94=AF?=
 =?UTF-8?q?=E6=8C=81=E5=A4=9A=E8=BE=93=E5=87=BA=E6=96=B9=E5=BC=8F=E7=9A=84?=
 =?UTF-8?q?=E6=97=A5=E5=BF=97=E7=B3=BB=E7=BB=9F?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- 添加Logger接口定义
- 实现ConsoleLogger控制台输出功能
- 实现FileLogger文件输出功能，支持文件大小限制和轮转
- 实现MultiLogger同时输出到多个目标的功能
- 添加基本日志记录示例和测试用例
```
---
 day05/homework/log/app.log |   2 +
 day05/homework/log/main.go | 106 +++++++++++++++++++++++++++++++++++++
 2 files changed, 108 insertions(+)
 create mode 100644 day05/homework/log/app.log
 create mode 100644 day05/homework/log/main.go

diff --git a/day05/homework/log/app.log b/day05/homework/log/app.log
new file mode 100644
index 0000000..7d82f02
--- /dev/null
+++ b/day05/homework/log/app.log
@@ -0,0 +1,2 @@
+应用启动
+用户登录
diff --git a/day05/homework/log/main.go b/day05/homework/log/main.go
new file mode 100644
index 0000000..f9aa5a5
--- /dev/null
+++ b/day05/homework/log/main.go
@@ -0,0 +1,106 @@
+package main
+
+import (
+	"os"
+)
+
+// 作业2：日志系统（难度：⭐⭐）
+// 题目： 实现支持多种输出方式的日志系统。
+
+// 1. 定义Logger接口
+type Logger interface {
+	Log(message string)
+}
+
+// 2. 实现ConsoleLogger（控制台输出）
+type ConsoleLogger struct{}
+
+func (c *ConsoleLogger) Log(message string) {
+	println("控制台日志:", message)
+}
+
+// 3. 实现FileLogger（文件输出）
+type FileLogger struct {
+	filename string
+	logFile  *os.File
+	size     int64
+}
+
+func (f *FileLogger) Log(message string) {
+	// 模拟文件写入
+	println("文件日志:", message, "写入到文件:", f.filename)
+
+	// 如果没有指定文件名，使用默认文件名
+	if f.filename == "" {
+		f.filename = "app.log"
+	}
+
+	// O_APPEND
+	if f.logFile == nil {
+		logFile, err := os.OpenFile(f.filename, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
+		if err != nil {
+			panic(err)
+		}
+		// 获取当前日志文件的大小
+		fileInfo, err := f.logFile.Stat()
+		if err != nil {
+			panic(err)
+		}
+		// 初始文件大小
+		f.size = fileInfo.Size()
+		f.logFile = logFile
+	}
+
+	// 如果文件大小超过10M，则创建新的文件
+	if f.size >= 10*1024*1024 {
+		f.logFile.Close()
+		f.filename = f.filename + ".1"
+		logFile, err := os.OpenFile(f.filename, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0644)
+		if err != nil {
+			panic(err)
+		}
+		f.logFile = logFile
+		f.size = 0
+	}
+
+	n, err := f.logFile.WriteString(message + "\n")
+	if err != nil {
+		panic(err)
+	}
+	f.size += int64(n)
+}
+
+// 4. 实现MultiLogger（同时输出到多个地方）
+type MultiLogger struct {
+	loggers []Logger
+}
+
+// 5. 实现MultiLogger
+func (m *MultiLogger) Log(message string) {
+	for _, logger := range m.loggers {
+		logger.Log(message)
+	}
+}
+
+func (m *MultiLogger) Close() {
+	for _, logger := range m.loggers {
+		if fileLogger, ok := logger.(*FileLogger); ok {
+			if fileLogger.logFile != nil {
+				fileLogger.logFile.Close()
+			}
+		}
+	}
+}
+
+func main() {
+	logger := &MultiLogger{
+		loggers: []Logger{
+			&ConsoleLogger{},
+			&FileLogger{filename: "app.log"},
+		},
+	}
+	defer logger.Close()
+
+	logger.Log("应用启动")
+	logger.Log("用户登录")
+}