Question

我是刚开始进行后端开发的人。我正在尝试使用MySQL数据库创建REST API。

func getUsers(w http.ResponseWriter, r *http.Request) {
    db, err := sql.Open("mysql", "root:mypassword@tcp(127.0.0.1:3306/test)")
    if err != nil {
        panic(err.Error())
    }
    results, err := db.Query("Select * from users")
    if err != nil {
        panic(err.Error())
    }
    for results.Next() {
        var user User
        err = results.Scan(&user.FirstName)
        if err != nil {
            panic(err.Error)
        }
        fmt.Println(user.FirstName)
    }
    //scores is an array that i have already created just to return dummy data
    json.NewEncoder(w).Encode(scores)
}

我收到此错误：

http: panic serving [::1]:54508: invalid DSN: network address not terminated (missing closing brace)
goroutine 5 [running]:
net/http.(*conn).serve.func1(0xc42009abe0)
        /usr/local/go/src/net/http/server.go:1726 +0xd0
panic(0x129cea0, 0xc420010ec0)
        /usr/local/go/src/runtime/panic.go:505 +0x229
main.getUsers(0x134bca0, 0xc42011e000, 0xc42011c200)
        /Users/tushar/go/src/github.com/tushar/jump/main.go:62 +0x33f
net/http.HandlerFunc.ServeHTTP(0x1326230, 0x134bca0, 0xc42011e000, 0xc42011c200)
        /usr/local/go/src/net/http/server.go:1947 +0x44
github.com/gorilla/mux.(*Router).ServeHTTP(0xc420110000, 0x134bca0, 0xc42011e000, 0xc42011c200)
        /Users/tushar/go/src/github.com/gorilla/mux/mux.go:162 +0xed
net/http.serverHandler.ServeHTTP(0xc42008aea0, 0x134bca0, 0xc42011e000, 0xc42011c000)
        /usr/local/go/src/net/http/server.go:2694 +0xbc
net/http.(*conn).serve(0xc42009abe0, 0x134bf60, 0xc420062240)
        /usr/local/go/src/net/http/server.go:1830 +0x651
created by net/http.(*Server).Serve
        /usr/local/go/src/net/http/server.go:2795 +0x27b

我无法理解该问题。

在没有数据库查询的情况下工作正常。

编辑1： 编辑的sql.Open将右括号改为root:mypassword@tcp(127.0.0.1:3306)/test 查询时效果很好

但是在插入db时我感到恐慌

func insertUsers(w http.ResponseWriter, r *http.Request) {
    db, err := sql.Open("mysql", "root:mypassword@tcp(127.0.0.1:3306)/test")
    if err != nil {
        panic(err.Error())
    }
    insert, err := db.Query("Insert into users (personId,firstName,lastName) values(20,tushar,saha)")
    if err != nil {
        panic(err.Error)
    }
    defer insert.Close()
}

这是错误1

2018/06/23 11:54:10 http: panic serving [::1]:54802: 0x126a8b0
goroutine 19 [running]:
net/http.(*conn).serve.func1(0xc4200aebe0)
        /usr/local/go/src/net/http/server.go:1726 +0xd0
panic(0x129bb20, 0xc42016a020)
        /usr/local/go/src/runtime/panic.go:505 +0x229
main.insertUsers(0x134bc80, 0xc42013c000, 0xc420138200)
        /Users/tushar/go/src/github.com/tushar/jump/main.go:50 +0x15d
net/http.HandlerFunc.ServeHTTP(0x1326218, 0x134bc80, 0xc42013c000, 0xc420138200)
        /usr/local/go/src/net/http/server.go:1947 +0x44
github.com/gorilla/mux.(*Router).ServeHTTP(0xc42012c000, 0x134bc80, 0xc42013c000, 0xc420138200)
        /Users/tushar/go/src/github.com/gorilla/mux/mux.go:162 +0xed
net/http.serverHandler.ServeHTTP(0xc420095040, 0x134bc80, 0xc42013c000, 0xc420138000)
        /usr/local/go/src/net/http/server.go:2694 +0xbc
net/http.(*conn).serve(0xc4200aebe0, 0x134bf40, 0xc42009a200)
        /usr/local/go/src/net/http/server.go:1830 +0x651
created by net/http.(*Server).Serve
        /usr/local/go/src/net/http/server.go:2795 +0x27b

Answer 1

sql.Open()方法的DSN（即第二个）参数格式错误。

仅地址部分（127.0.0.1:3306）被括在括号中。您还已经在括号中包括了数据库名称。

尝试以下方法：

db, err := sql.Open("mysql", "root:mypassword@tcp(127.0.0.1:3306)/test")

documented格式为：

[username[:password]@][protocol[(address)]]/dbname[?param1=value1&...&paramN=valueN]

响应“ EDIT 1”

err.Error() is a method.

在插入查询的错误处理块中，您没有调用该方法。相反，您要打印出它的内存位置。

if err != nil {
    panic(err.Error)
}

如果您实际调用该方法（类似于sql.Open()在错误处理块中的方法），则会打印出错误消息，该错误消息可以指出问题所在。

if err != nil {
    panic(err.Error())
}

DSN无效：网络地址未终止（缺少右括号）

1 个答案:

响应“ EDIT 1”