diff --git a/book/config/config.go b/book/config/config.go
index 5d8fbae..7a59656 100644
--- a/book/config/config.go
+++ b/book/config/config.go
@@ -189,12 +189,12 @@ func (l *Log) Logger() *zerolog.Logger {
 		// 带上中间信息Any
 		// book/controller/book.go:60
 		root := zerolog.New(io.MultiWriter(writers...)).With().Timestamp().Any("服务", "book-api")
-
 		if l.CallerDeep > 0 {
-			zerolog.CallerMarshalFunc = l.CallerMarshalFunc
+			// 启用caller
 			root = root.Caller()
+			// 配置自定义caller
+			zerolog.CallerMarshalFunc = l.CallerMarshalFunc
 		}
-
 		// 带有这些上下文信息的Logger对象 提前出来，作为全局Logger对象，供全局使用
 		l.SetRoot(root.Logger().Level(l.Level))
 	}
diff --git a/book/controller/book.go b/book/controller/book.go
index 0fe7014..59dc0c5 100644
--- a/book/controller/book.go
+++ b/book/controller/book.go
@@ -2,9 +2,11 @@ package controller
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/rs/zerolog"
 	"gitlab.com/go-course-project/go17/book/config"
+	"gitlab.com/go-course-project/go17/book/exception"
 	"gitlab.com/go-course-project/go17/book/model"
 	"gorm.io/gorm"
 )
@@ -42,8 +44,12 @@ func (c *BookController) GetBook(ctx context.Context, req *GetBookRequest) (*mod
 	ins := &model.Book{}
 
 	if err := c.db.WithContext(ctx).Where("isbn = ?", req.Isbn).Take(ins).Error; err != nil {
-		return nil, err
+		if err == gorm.ErrRecordNotFound {
+			return nil, exception.ErrNotFound("%d not found", req.Isbn)
+		}
+		return nil, fmt.Errorf("get book error, %s", err)
 	}
+
 	return ins, nil
 }
 
diff --git a/book/controller/book_test.go b/book/controller/book_test.go
index d101180..33e5d52 100644
--- a/book/controller/book_test.go
+++ b/book/controller/book_test.go
@@ -5,14 +5,25 @@ import (
 	"testing"
 
 	"gitlab.com/go-course-project/go17/book/controller"
+	"gitlab.com/go-course-project/go17/book/exception"
 	"gitlab.com/go-course-project/go17/book/model"
 )
 
 func TestGetBook(t *testing.T) {
 	book := controller.NewBookController()
 	ins, err := book.GetBook(context.Background(), &controller.GetBookRequest{
-		Isbn: 5,
+		Isbn: 100,
 	})
+
+	if err != nil && exception.IsNotFound(err) {
+		t.Log("is not found error")
+	}
+	// if errors.Is(err, gorm.ErrRecordNotFound) {
+	// 	t.Log("is not found error")
+	// }
+	// if err.Error() == "record not found" {
+	// 	t.Log(" string equal is not found error")
+	// }
 	if err != nil {
 		t.Fatal(err)
 	}
diff --git a/book/controller/logs/app.log b/book/controller/logs/app.log
index 5428aba..a80ae5f 100644
--- a/book/controller/logs/app.log
+++ b/book/controller/logs/app.log
@@ -1,3 +1,6 @@
 {"level":"debug","time":"2024-11-23T15:07:35+08:00","caller":"book/controller/book.go:60","message":"req 请求信息: {\n  \"title\": \"Go语言\",\n  \"author\": \"will\",\n  \"price\": 10,\n  \"is_sale\": null\n}"}
 {"level":"debug","time":"2024-11-23T15:11:42+08:00","caller":"book/controller/book.go:60","message":"req 请求信息: {\n  \"title\": \"Go语言\",\n  \"author\": \"will\",\n  \"price\": 10,\n  \"is_sale\": null\n}"}
 {"level":"debug","服务":"book-api","time":"2024-11-23T15:14:21+08:00","caller":"book/controller/book.go:60","message":"req 请求信息: {\n  \"title\": \"Go语言\",\n  \"author\": \"will\",\n  \"price\": 10,\n  \"is_sale\": null\n}"}
+{"level":"debug","服务":"book-api","time":"2024-11-23T15:24:12+08:00","caller":"book/controller/book.go:61","message":"req 请求信息: {\n  \"title\": \"Go语言\",\n  \"author\": \"will\",\n  \"price\": 10,\n  \"is_sale\": null\n}"}
+{"level":"debug","服务":"book-api","time":"2024-11-23T15:25:07+08:00","caller":"book/controller/book.go:61","message":"req 请求信息: {\n  \"title\": \"Go语言\",\n  \"author\": \"will\",\n  \"price\": 10,\n  \"is_sale\": null\n}"}
+{"level":"debug","服务":"book-api","time":"2024-11-23T15:34:19+08:00","caller":"/Users/yumaojun/Projects/go-course/go17/book/controller/book.go:61","message":"req 请求信息: {\n  \"title\": \"Go语言\",\n  \"author\": \"will\",\n  \"price\": 10,\n  \"is_sale\": null\n}"}
diff --git a/book/exception/README.md b/book/exception/README.md
new file mode 100644
index 0000000..e27c957
--- /dev/null
+++ b/book/exception/README.md
@@ -0,0 +1,38 @@
+# 业务异常
+
+```go
+func TestGetBook(t *testing.T) {
+	book := controller.NewBookController()
+	ins, err := book.GetBook(context.Background(), &controller.GetBookRequest{
+		Isbn: 100,
+	})
+
+	if errors.Is(err, gorm.ErrRecordNotFound) {
+		t.Log("is not found error")
+	}
+	if err.Error() == "record not found" {
+		t.Log(" string equal is not found error")
+	}
+
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Log(ins)
+}
+```
+
+设立一种统一的业务异常机制, 业内最常见的 就是 定义业务异常Code
+
++ Code: 业务异常码
++ Message: 异常的具体信息
++ Reason: 导致这个异常的原因
+
+业务异常是错误的一部分, 是一个error的一种实现
+
+```go
+// The error built-in interface type is the conventional interface for
+// representing an error condition, with the nil value representing no error.
+type error interface {
+	Error() string
+}
+```
\ No newline at end of file
diff --git a/book/exception/errors.go b/book/exception/errors.go
new file mode 100644
index 0000000..73a8625
--- /dev/null
+++ b/book/exception/errors.go
@@ -0,0 +1,19 @@
+package exception
+
+import "fmt"
+
+const (
+	ERR_NOT_FOUND = 404
+)
+
+func IsNotFound(err error) bool {
+	if v, ok := (err).(*ApiExceptin); ok {
+		return v.Code == ERR_NOT_FOUND
+	}
+
+	return false
+}
+
+func ErrNotFound(format string, a ...any) *ApiExceptin {
+	return NewApiExceptin(ERR_NOT_FOUND, fmt.Sprintf(format, a...))
+}
diff --git a/book/exception/exception.go b/book/exception/exception.go
new file mode 100644
index 0000000..07e4412
--- /dev/null
+++ b/book/exception/exception.go
@@ -0,0 +1,21 @@
+package exception
+
+import (
+	"fmt"
+)
+
+func NewApiExceptin(code int, message string) *ApiExceptin {
+	return &ApiExceptin{
+		Code:    code,
+		Message: message,
+	}
+}
+
+type ApiExceptin struct {
+	Code    int    `json:"code"`
+	Message string `json:"message"`
+}
+
+func (e *ApiExceptin) Error() string {
+	return fmt.Sprintf("[%d] %s", e.Code, e.Message)
+}