Go语言API开发：正确解析JSON POST请求体

package main

import (
    "encoding/json"
    "log"
    "net/http"
)

type test_struct struct {
    Test string
}

func testHandlerMisconception(rw http.ResponseWriter, req *http.Request) {
    req.ParseForm() // 错误：尝试解析JSON作为表单数据
    log.Println(req.Form)
    // LOG: map[{"test": "that"}:[]] - JSON字符串被当作一个表单键

    var t test_struct
    for key, _ := range req.Form {
        log.Println(key)
        // LOG: {"test": "that"}
        err := json.Unmarshal([]byte(key), &t) // 尝试将表单键（整个JSON字符串）反序列化
        if err != nil {
            log.Printf("Error unmarshalling form key: %v", err)
        }
    }
    log.Println("Parsed value (misconception):", t.Test)
    // LOG: that (虽然最终得到了数据，但过程极其不优雅且脆弱)
}

func main() {
    http.HandleFunc("/test_misconception", testHandlerMisconception)
    log.Fatal(http.ListenAndServe(":8082", nil))
}

package main

import (
    "encoding/json"
    "fmt"
    "log"
    "net/http"
)

// test_struct 定义了预期的JSON数据结构
type test_struct struct {
    Test string `json:"test"` // 使用json tag确保字段名匹配
}

// handleTest 处理 /test 路径的POST请求
func handleTest(rw http.ResponseWriter, req *http.Request) {
    // 1. 验证请求方法
    if req.Method != http.MethodPost {
        http.Error(rw, "Method Not Allowed", http.StatusMethodNotAllowed)
        return
    }

    // 2. 使用 json.NewDecoder 直接从请求体中解码
    // req.Body 是一个 io.Reader，非常适合 NewDecoder
    decoder := json.NewDecoder(req.Body)
    var data test_struct
    err := decoder.Decode(&data) // 将请求体中的JSON解码到data结构体

    // 3. 错误处理
    if err != nil {
        // 处理解码错误，例如JSON格式不正确或IO错误
        log.Printf("Error decoding JSON from request body: %v", err)
        http.Error(rw, "Bad Request: Invalid JSON format or malformed request", http.StatusBadRequest)
        return
    }

    // 4. 成功解析数据并进行业务逻辑处理
    log.Printf("Successfully received data: %+v", data)
    fmt.Fprintf(rw, "Successfully processed: %s", data.Test)
}

func main() {
    http.HandleFunc("/test", handleTest)
    log.Println("Server starting on :8082. Listening for POST requests on /test")
    log.Fatal(http.ListenAndServe(":8082", nil))
}

curl -X POST -H "Content-Type: application/json" -d "{\"test\": \"that\"}" http://localhost:8082/test