从Java到Go：后端服务迁移的考量与实践建议

package main

import (
    "context"
    "fmt"
    "log"
    "os/exec"
    "sync"
    "time"
)

// CommandResult 结构体用于存储命令执行结果
type CommandResult struct {
    ID     int
    Command string
    Output string
    Error  error
}

// executeCommand 执行单个Shell命令
func executeCommand(ctx context.Context, id int, cmdStr string) CommandResult {
    select {
    case <-ctx.Done():
        return CommandResult{ID: id, Command: cmdStr, Error: ctx.Err()}
    default:
    }

    cmd := exec.CommandContext(ctx, "sh", "-c", cmdStr) // 使用 sh -c 来执行复杂命令
    output, err := cmd.CombinedOutput() // CombinedOutput捕获标准输出和标准错误

    return CommandResult{
        ID:     id,
        Command: cmdStr,
        Output: string(output),
        Error:  err,
    }
}

func main() {
    commands := []string{
        "echo 'Hello from command 1'",
        "sleep 2 && echo 'Hello from command 2 after 2s'",
        "ls -l /nonexistent_dir", // 模拟一个错误命令
        "echo 'Hello from command 3'",
    }

    var wg sync.WaitGroup
    resultsChan := make(chan CommandResult, len(commands)) // 带缓冲的通道

    ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second) // 设置整体超时
    defer cancel()

    fmt.Println("Starting parallel command execution...")

    for i, cmd := range commands {
        wg.Add(1)
        go func(id int, command string) {
            defer wg.Done()
            result := executeCommand(ctx, id, command)
            resultsChan <- result // 将结果发送到通道
        }(i+1, cmd)
    }

    wg.Wait()      // 等待所有Goroutines完成
    close(resultsChan) // 关闭通道，表示没有更多结果会发送

    // 从通道中收集并处理结果
    for res := range resultsChan {
        if res.Error != nil {
            log.Printf("Command %d ('%s') failed: %v, Output:\n%s", res.ID, res.Command, res.Error, res.Output)
        } else {
            fmt.Printf("Command %d ('%s') completed successfully. Output:\n%s", res.ID, res.Command, res.Output)
        }
        fmt.Println("---")
    }

    fmt.Println("All commands processed.")
}

package main

import (
    "database/sql"
    "fmt"
    "log"
    "time"

    _ "github.com/go-sql-driver/mysql" // 引入MySQL驱动，下划线表示只引入包的init函数
)

// CommandRecord 结构体用于存储数据库中的命令信息
type CommandRecord struct {
    ID        int
    Command   string
    Output    string
    Timestamp time.Time
}

func main() {
    // 替换为你的MySQL连接信息
    dsn := "user:password@tcp(127.0.0.1:3306)/database_name?charset=utf8mb4&parseTime=True&loc=Local"

    db, err := sql.Open("mysql", dsn)
    if err != nil {
        log.Fatalf("Failed to open database connection: %v", err)
    }
    defer db.Close()

    // 尝试连接数据库
    err = db.Ping()
    if err != nil {
        log.Fatalf("Failed to connect to database: %v", err)
    }
    fmt.Println("Successfully connected to MySQL!")

    // 1. 插入一条新的命令执行结果
    insertStmt, err := db.Prepare("INSERT INTO command_logs (command, output, timestamp) VALUES (?, ?, ?)")
    if err != nil {
        log.Fatalf("Failed to prepare insert statement: %v", err)
    }
    defer insertStmt.Close()

    res, err := insertStmt.Exec("ls -l /tmp", "total 0\n-rw-r--r-- 1 user user 0 Jan 1 00:00 test.txt", time.Now())
    if err != nil {
        log.Fatalf("Failed to execute insert statement: %v", err)
    }
    lastID, _ := res.LastInsertId()
    fmt.Printf("Inserted new log with ID: %d\n", lastID)

    // 2. 查询所有命令日志
    rows, err := db.Query("SELECT id, command, output, timestamp FROM command_logs ORDER BY timestamp DESC LIMIT 5")
    if err != nil {
        log.Fatalf("Failed to query command logs: %v", err)
    }
    defer rows.Close()

    fmt.Println("\nRecent Command Logs:")
    for rows.Next() {
        var record CommandRecord
        if err := rows.Scan(&record.ID, &record.Command, &record.Output, &record.Timestamp); err != nil {
            log.Printf("Failed to scan row: %v", err)
            continue
        }
        fmt.Printf("ID: %d, Command: '%s', Output: '%s', Time: %s\n", record.ID, record.Command, record.Output, record.Timestamp.Format("2006-01-02 15:04:05"))
    }
    if err = rows.Err(); err != nil {
        log.Fatalf("Error iterating rows: %v", err)
    }
}