Question

我正在学习JavaScript＆amp;阿贾克斯＆amp;的NodeJS。

我正在尝试构建一个显示服务器字符串的网页。

服务器代码：

#include <iostream>
#include <string>
#include <vector>
#include <memory>

class employee
{
    std::string NAME;
    int NUM;
    int Enum = 0;
public:
    std::vector<std::shared_ptr<employee>> childs;
    employee(std::string name, int num) :NAME(name), NUM(num)
    {
        childs.resize(num);
    }
    std::string getName()
    {
        return NAME;
    }
    int getNum()
    {
        return NUM;
    }
    void setEnum(int num)
    {
        Enum = num;
    }
    int getEnum()
    {
        return Enum;
    }
};

class eTree
{
private:
    std::shared_ptr<employee> proot;
public:
    eTree(employee node) { proot = std::make_shared<employee> (node); }
    void buildTree(std::shared_ptr<employee> parent);
    std::shared_ptr<employee> getP() { return proot; }
    std::shared_ptr<employee> buildChilds(employee &parent, int i);
};
void eTree::buildTree(std::shared_ptr<employee> parent)
{
    int num = parent->getNum();
    if (num != 0)
    {
        for (int i = 0; i < num; i++)
        {
            (*parent).childs[i] = buildChilds(*parent, i);
            std::cout << (*parent).childs[i] << std::endl;
            buildTree((*parent).childs[i]);
        }
        int eNum = (*parent).getNum();
        for (int j = 0; j < num; j++)
        {
            eNum += (*((*parent).childs[j])).getEnum();
        }
        (*parent).setEnum(eNum);
    }
}
std::shared_ptr<employee> eTree::buildChilds(employee &parent, int i)
{
    std::string name;
    int num;
    std::cout << "Enter the name of " << parent.getName() << "'s " << i + 1 << " child:" << std::endl;
    std::cin >> name;
    std::cout << "How many employee work for " << parent.getName() << "'s " << i + 1 << " child:" << std::endl;
    std::cin >> num;
//  employee child(name, num);
    std::shared_ptr<employee> pchild (new employee(name, num));
//  std::shared_ptr<employee> pchild = std::make_shared<employee>(child);

    return pchild;
}

void more3(employee parent);
void noChild(employee parent);

int main()
{
    using namespace std;
    std::string name;
    cout << "Enter the employee's name: ";
    cin >> name;
    int num;
    cout << "How many employees work for him/her: ";
    cin >> num;
    employee root(name, num);
    shared_ptr<employee> proot = make_shared<employee> (root);
    eTree tree(root);
    tree.buildTree(proot);

    cout << tree.getP()->childs[0] << endl;
    cout << tree.getP()->childs[1] << endl;

    return 0;
}

客户端代码：

var express = require('express');
var app = express();

app.get('/sms', function (req, res) {
   console.log("Got request: " + req);
   res.send('Hello World');
   console.log("Send result");
})

var server = app.listen(8081, function () {

  var host = server.address().address
  var port = server.address().port

  console.log("Listening at http://%s:%s", host, port)

})

点击按钮后，我得到一个空字符串。

这里的日志：状态：1状态：0 Ajax1.html：1 XMLHttpRequest无法加载http://127.0.0.1:8081/sms。 No＆＃39; Access-Control-Allow-Origin＆＃39;标头出现在请求的资源上。起源＆＃39; null＆＃39;因此不允许访问。 Ajax1.html：28状态：4状态：0 Ajax1.html：35得到结果：

为什么我得到一个空字符串？我错过了什么？感谢

Answer 1

您的客户端代码和服务器代码必须位于相同的源（相同的主机名，相同的端口）才能发出AJAX请求。

127.0.0.1 无法将AJAX请求发送到127.0.0.1:8081。

要修复，请将node.js反向代理到相同的主机名（推荐），或者在node.js中设置Access-Control-Allow-Origin。

为什么我得到空的结果？

1 个答案: