英文:
Golang: Convert to JSON.GZ and write to file
问题
尝试使用我的数据实现以下输出：
- 将数据转换为JSON字符串并写入文件：output.json（这部分已经实现）
- 对JSON字符串进行Gzip压缩，并将其写入json.gz文件：output.json.gz（不起作用）
代码运行正常，并成功写入两个文件。但是当我尝试解压缩gzipped文件时，会出现以下错误：Data error in 'output.json'. File is broken
以下是代码：
package main
import (
"bytes"
"compress/gzip"
"encoding/json"
"fmt"
"io/ioutil"
)
type Generic struct {
Name string
Cool bool
Rank int
}
func main() {
generic := Generic{"Golang", true, 100}
fileJson, _ := json.Marshal(generic)
err := ioutil.WriteFile("output.json", fileJson, 0644)
if err != nil {
fmt.Printf("WriteFileJson ERROR: %+v", err)
}
var fileGZ bytes.Buffer
zipper := gzip.NewWriter(&fileGZ)
defer zipper.Close()
_, err = zipper.Write([]byte(string(fileJson)))
if err != nil {
fmt.Printf("zipper.Write ERROR: %+v", err)
}
err = ioutil.WriteFile("output.json.gz", []byte(fileGZ.String()), 0644)
if err != nil {
fmt.Printf("WriteFileGZ ERROR: %+v", err)
}
}
我错过了什么？
英文:
Trying to accomplish the following output with my data:
- Convert to JSON string and write to file: output.json (this part is working)
- Gzip Compress the JSON string and write that to a json.gz file: output.json.gz (NOT WORKING)
The code runs fine and writes to both files. But the gzipped file gives this error when I try to unzip it: Data error in 'output.json'. File is broken
Here's the code:
package main
import (
"bytes"
"compress/gzip"
"encoding/json"
"fmt"
"io/ioutil"
)
type Generic struct {
Name string
Cool bool
Rank int
}
func main() {
generic := Generic{"Golang", true, 100}
fileJson, _ := json.Marshal(generic)
err := ioutil.WriteFile("output.json", fileJson, 0644)
if err != nil {
fmt.Printf("WriteFileJson ERROR: %+v", err)
}
var fileGZ bytes.Buffer
zipper := gzip.NewWriter(&fileGZ)
defer zipper.Close()
_, err = zipper.Write([]byte(string(fileJson)))
if err != nil {
fmt.Printf("zipper.Write ERROR: %+v", err)
}
err = ioutil.WriteFile("output.json.gz", []byte(fileGZ.String()), 0644)
if err != nil {
fmt.Printf("WriteFileGZ ERROR: %+v", err)
}
}
What did I miss?
答案1
得分: 8
你需要在完成写入操作后立即调用zipper.Close()。
http://play.golang.org/p/xNeMg3aXxO
_, err = zipper.Write(fileJson)
if err != nil {
log.Fatalf("zipper.Write ERROR: %+v", err)
}
err := zipper.Close() // 显式调用并检查错误
调用`defer zipper.Close()`会在主函数结束时触发调用。在调用`.Close()`之前，数据将被写入一个中间缓冲区而不是刷新到实际文件中。
<details>
<summary>英文:</summary>
You need to call zipper.Close() immediately after finishing writing
http://play.golang.org/p/xNeMg3aXxO
_, err = zipper.Write(fileJson)
if err != nil {
log.Fatalf("zipper.Write ERROR: %+v", err)
}
err := zipper.Close() // call it explicitly and check error
Calling `defer zipper.Close()` would trigger the call at the end of the main function. Until you call `.Close()` the data is being written to an intermediate buffer and not flushed to the actual file.
</details>
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