小编Rah*_*hul的帖子

我按照mongodb安装文档中提到的所有步骤进行操作.

对于ubuntu 16.04

第1步:

sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 2930ADAE8CAF5059EE73BB4B58712A2291FA4AD5

第2步:

echo "deb [ arch=amd64,arm64 ] https://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.6 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.6.list

第3步:

sudo apt-get update

第4步:

sudo apt-get install -y mongodb-org

第5步:

sudo service mongod start

当我开始mongodb得到一个错误

"Failed to start mongod.service: Unit mongod.service not found." please help me to solve this.

我正在使用 Angular 7.2。当我输入时ng serve，我面临以下问题：

致命错误：接近堆限制的无效标记压缩分配失败 - JavaScript 堆内存不足

这意味着什么？我该如何解决？

完整的错误信息是：

FATAL ERROR: Ineffective mark-compacts near heap limit Allocation failed - JavaScript heap out of memory
1: 0x8f9d10 node::Abort() [ng serve --aot --proxy-config proxy.conf.json --host 0.0.0.0 --disable-host-check --live-reload --progress]
2: 0x8f9d5c  [ng serve --aot --proxy-config proxy.conf.json --host 0.0.0.0 --disable-host-check --live-reload --progress]
3: 0xaffd0e v8::Utils::ReportOOMFailure(v8::internal::Isolate*, char const*, bool) [ng serve --aot --proxy-config proxy.conf.json --host 0.0.0.0 --disable-host-check --live-reload --progress]
4: 0xafff44 v8::internal::V8::FatalProcessOutOfMemory(v8::internal::Isolate*, char const*, bool) [ng serve --aot --proxy-config proxy.conf.json …

我在 reuest 转到 servlet 时遇到错误，我尝试了很多来解决这个问题，但没有得到正确的解决方案。

Registration.java（Servlet 类文件）

package login;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;
import org.hibernate.SessionFactory;

@WebServlet("/Registration")
public class Registration extends HttpServlet {
   private static final long serialVersionUID = 1L;


public Registration() {
    super();
 }


protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

     String username =  request.getParameter("username");
     String password =  request.getParameter("password");
     String name =  request.getParameter("name");

     Users u = new Users();
     u.setUsername(username);
     u.setPassword(password);
     u.setName(name);

     String uname …

I have two arrays and i want to combine them to get common result. array should be combine on the basis of user_id not on index How would i do this?

Array 1:

var array1 = [{
  "name": "Smart Test Pool",
  "user_id": 1,
  "total_time": "15.0",
}];

Array 2:

var array2 = [{
  "user_id": 1,
  "total_hours_worked_milliseconds": 60060000,
  "total_time_unshedule_milliseconds": 540000
}];

Result :

var result = [{
  "name": "Smart Test Pool",
  "user_id": 1,
  "total_time": "15.0",
  "total_hours_worked_milliseconds": 60060000,
  "total_time_unshedule_milliseconds": 540000
}];