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Go语言net/http库使用详解

news 2025/9/27 9:24:46

1 概述

net/http是Go语言标准库中用于处理HTTP协议的核心组件，它提供了完整HTTP客户端和服务器实现。这个包让开发者能够快速构建高性能的Web服务，无需依赖第三方框架。

1.1 主要特性

内置高性能HTTP服务器：直接支持并发请求处理
简洁的API设计：易于上手和使用
完整的HTTP协议支持：支持HTTP/1.x和HTTP/2
强大的路由机制：灵活的路由匹配和处理
中间件支持：可扩展的中间件架构

2 HTTP服务器开发

2.1 基本服务器搭建

以下是创建一个最简单HTTP服务器的示例：

package mainimport ("fmt""net/http"
)func main() {// 注册处理函数http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {fmt.Fprint(w, "Hello, World!")})// 启动服务器fmt.Println("Starting server on :8080")err := http.ListenAndServe(":8080", nil)if err != nil {fmt.Printf("Error starting server: %v\n", err)}
}

2.2 处理不同的HTTP方法

可以根据请求方法执行不同的逻辑：

func handler(w http.ResponseWriter, r *http.Request) {switch r.Method {case http.MethodGet:fmt.Fprint(w, "This is a GET request.")case http.MethodPost:fmt.Fprint(w, "This is a POST request.")default:http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)}
}

2.3 请求参数处理

查询参数（URL参数）

func queryHandler(w http.ResponseWriter, r *http.Request) {name := r.URL.Query().Get("name")age := r.URL.Query().Get("age")fmt.Fprintf(w, "Hello, %s! Age: %s", name, age)
}

表单数据

func formHandler(w http.ResponseWriter, r *http.Request) {if r.Method == "POST" {err := r.ParseForm()if err != nil {http.Error(w, "Bad Request", http.StatusBadRequest)return}username := r.FormValue("username")password := r.FormValue("password")fmt.Fprintf(w, "Username: %s, Password: %s", username, password)}
}

JSON请求体

func jsonHandler(w http.ResponseWriter, r *http.Request) {type RequestData struct {Name  string `json:"name"`Email string `json:"email"`}var data RequestDataerr := json.NewDecoder(r.Body).Decode(&data)if err != nil {http.Error(w, err.Error(), http.StatusBadRequest)return}fmt.Fprintf(w, "Name: %s, Email: %s", data.Name, data.Email)
}

2.4 路由管理

使用ServeMux进行路由管理

func main() {mux := http.NewServeMux()mux.HandleFunc("/", homeHandler)mux.HandleFunc("/users", usersHandler)mux.HandleFunc("/posts", postsHandler)http.ListenAndServe(":8080", mux)
}

动态路由参数（需配合第三方路由库）

虽然标准库的ServeMux不支持动态路由参数，但可以结合正则表达式或使用第三方库实现。

3 HTTP客户端开发

3.1 发送GET请求

package mainimport ("fmt""io""net/http"
)func main() {resp, err := http.Get("https://jsonplaceholder.typicode.com/posts/1")if err != nil {fmt.Printf("Error: %v\n", err)return}defer resp.Body.Close()body, err := io.ReadAll(resp.Body)if err != nil {fmt.Printf("Error reading body: %v\n", err)return}fmt.Println(string(body))
}

3.2 发送POST请求

func main() {data := []byte(`{"title": "foo", "body": "bar", "userId": 1}`)resp, err := http.Post("https://jsonplaceholder.typicode.com/posts","application/json",bytes.NewBuffer(data),)if err != nil {fmt.Printf("Error: %v\n", err)return}defer resp.Body.Close()// 处理响应...
}

3.3 自定义请求

使用http.NewRequest可以创建更复杂的请求：

func main() {// 创建请求data := []byte(`{"name": "Go"}`)req, err := http.NewRequest("POST", "https://httpbin.org/post", bytes.NewBuffer(data))if err != nil {fmt.Printf("Error creating request: %v\n", err)return}// 设置请求头req.Header.Set("Content-Type", "application/json")req.Header.Set("Authorization", "Bearer token123")// 发送请求client := &http.Client{Timeout: time.Second * 10,}resp, err := client.Do(req)if err != nil {fmt.Printf("Error sending request: %v\n", err)return}defer resp.Body.Close()// 处理响应...
}

3.4 客户端超时设置

func main() {client := &http.Client{Timeout: 10 * time.Second,}resp, err := client.Get("https://www.example.com")if err != nil {fmt.Printf("Error: %v\n", err)return}defer resp.Body.Close()
}

4 高级特性

4.1 中间件开发

中间件可以在处理HTTP请求前后执行特定逻辑：

func loggingMiddleware(next http.Handler) http.Handler {return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {start := time.Now()next.ServeHTTP(w, r)log.Printf("Request: %s %s processed in %v", r.Method, r.URL.Path, time.Since(start))})
}func authMiddleware(next http.Handler) http.Handler {return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {token := r.Header.Get("Authorization")if token != "valid-token" {http.Error(w, "Unauthorized", http.StatusUnauthorized)return}next.ServeHTTP(w, r)})
}func main() {mux := http.NewServeMux()mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {fmt.Fprint(w, "Hello, World!")})// 应用中间件handler := loggingMiddleware(authMiddleware(mux))http.ListenAndServe(":8080", handler)
}

4.2 静态文件服务

func main() {// 提供静态文件服务fs := http.FileServer(http.Dir("static"))http.Handle("/static/", http.StripPrefix("/static/", fs))http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {fmt.Fprint(w, "Main page")})http.ListenAndServe(":8080", nil)
}

4.3 Cookie处理

func cookieHandler(w http.ResponseWriter, r *http.Request) {// 读取Cookiecookie, err := r.Cookie("session")if err != nil {// 创建新Cookiecookie = &http.Cookie{Name:     "session",Value:    "session-id-123",Path:     "/",HttpOnly: true,}http.SetCookie(w, cookie)}fmt.Fprintf(w, "Cookie value: %s", cookie.Value)
}

4.4 JSON响应

func jsonResponseHandler(w http.ResponseWriter, r *http.Request) {type Response struct {Status  string `json:"status"`Message string `json:"message"`Data    interface{} `json:"data,omitempty"`}response := Response{Status:  "success",Message: "Data retrieved successfully",Data: map[string]interface{}{"id":   1,"name": "John Doe",},}w.Header().Set("Content-Type", "application/json")json.NewEncoder(w).Encode(response)
}

5 常见问题与解决方案

5.1 易错点及避免方法

易错点	问题描述	解决方案
资源泄露	未关闭响应体	总是使用`defer resp.Body.Close()`
路由冲突	路由匹配顺序错误	明确路由优先级，从具体到一般
阻塞操作	长时间运行的操作阻塞服务	使用goroutine处理耗时任务
内存泄漏	不当使用全局变量或缓存	合理管理资源生命周期

5.2 性能优化建议

连接复用：使用http.Client的默认连接池
超时设置：为客户端和服务器设置合理的超时时间
并发处理：利用Go的并发特性处理请求
静态资源缓存：合理设置缓存头减少重复传输

5.3 安全最佳实践

func secureHeadersMiddleware(next http.Handler) http.Handler {return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {// 设置安全相关的HTTP头w.Header().Set("X-Content-Type-Options", "nosniff")w.Header().Set("X-Frame-Options", "DENY")w.Header().Set("X-XSS-Protection", "1; mode=block")w.Header().Set("Strict-Transport-Security", "max-age=63072000; includeSubDomains")next.ServeHTTP(w, r)})
}

6 实战案例：完整的API服务

以下是一个完整的用户管理API示例：

package mainimport ("encoding/json""log""net/http""strconv""time""github.com/gorilla/mux"
)type User struct {ID    int    `json:"id"`Name  string `json:"name"`Email string `json:"email"`
}var users = []User{{ID: 1, Name: "Alice", Email: "alice@example.com"},{ID: 2, Name: "Bob", Email: "bob@example.com"},
}func getUsers(w http.ResponseWriter, r *http.Request) {w.Header().Set("Content-Type", "application/json")json.NewEncoder(w).Encode(users)
}func getUser(w http.ResponseWriter, r *http.Request) {w.Header().Set("Content-Type", "application/json")params := mux.Vars(r)id, _ := strconv.Atoi(params["id"])for _, user := range users {if user.ID == id {json.NewEncoder(w).Encode(user)return}}http.Error(w, "User not found", http.StatusNotFound)
}func createUser(w http.ResponseWriter, r *http.Request) {var user Usererr := json.NewDecoder(r.Body).Decode(&user)if err != nil {http.Error(w, err.Error(), http.StatusBadRequest)return}user.ID = len(users) + 1users = append(users, user)w.Header().Set("Content-Type", "application/json")w.WriteHeader(http.StatusCreated)json.NewEncoder(w).Encode(user)
}func loggingMiddleware(next http.Handler) http.Handler {return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {start := time.Now()next.ServeHTTP(w, r)log.Printf("%s %s %v", r.Method, r.URL.Path, time.Since(start))})
}func main() {router := mux.NewRouter()// 路由定义router.HandleFunc("/users", getUsers).Methods("GET")router.HandleFunc("/users/{id}", getUser).Methods("GET")router.HandleFunc("/users", createUser).Methods("POST")// 应用中间件router.Use(loggingMiddleware)log.Println("Server starting on :8080")log.Fatal(http.ListenAndServe(":8080", router))
}