如何从阅读器获取字符串？

In the strings module, there is a function func NewReader(s string) *Reader to create a Reader from a string.

How can you get/read the string from the strings.Reader?

You can use ioutil.ReadAll :

bytes, err := ioutil.ReadAll(r)
// err management here
s := string(bytes)

Not sure if this is what you want:

package main

import (
    "fmt"
    "log"
    "strings"
)

func main() {
    s := "Hello world"
    r := strings.NewReader(s)
    buf := make([]byte, 100)
    i, err := r.Read(buf)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("length string:", len(s))
    fmt.Println("bytes read:", i)
    fmt.Println(buf)
}

output:

length string: 11
bytes read: 11
[72 101 108 108 111 32 119 111 114 108 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 
 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0]