Java Spring Boot Download images from URL

2022-05-04 10:54 Oganesova imported from Stackoverflow

I am beginner... I have to write a program that should download an image from a URL and store it in a database.

In database I have book table (100.000row...) I have to download pictures for these books. I have to download at once.

How can I do this with Spring Boot With REST?? (Or with multithreading) I will be grateful for help.

See also questions close to this topic

Read each name in Array list to create seperate object for

I have a file that has student names, age, and an id number. I have a student class that holds the everything above for each student object. I stored all the names, id numbers. and age separately in an array list. Now im trying to assign the info to create a student object.

public class Student {
    private String lName;
    private int idNumber;
    private int age;

    public Student() {
        lName = "";
        idNumber = 0;
        age = 0;
    }
    public Student(String l, int i, int a) {
        lName = l;
        idNumber = i;
        age = a;
    }

    public void setName(String last) {
        lName = last;
    }

    public String getName() {
        return lName;
    }

    public void setIdNum(int num) {
        idNumber = num;
    }

    public int getIdNum() {
        return idNumber;
    }

    public void setAge(int a) {
        age = a;
    }

    public int getAge() {
        return age;
    }
}

My Text File looks something like this: This info is stored in parallel array lists. I don't quite get how to implement this into an object to pass it into my second contractor method.

  Josh          2134         19
  Smith         5256         21
  Rogers        9248         19
  Andrew        7742         20

Here's what I've tried;

public static void main(String[] args) {
    String file = "studentData.txt";
    Scanner reader = new Scanner(file);

    ArrayList<String> lastNames = lNames(file);
    ArrayList<Integer> idNumbers = idNum(file);
    ArrayList<Integer> ageList = ages(file);

    Scanner input = new Scanner(System.in);

    Student s1 = new Student();

    // confused about how to implement this constructor with the textile info
    for (int i = 0; i<idNumbers.size(); i++) {
        Student user = new Student(lastNames.get(i), idNumbers.get(i), ageList.get(i));
    }

    //user enters idNumber to display age
    System.out.println("Enter ID Number"); //exception handling to be added
    int idNum = input.nextInt();

    for (int i = 0; i<idNumbers.size(); i++) {
        if (idNum == idNumbers.get(i)) {
            s1.setAge(ageList.get(i));
            System.out.println(s1.getAge());

        }
    }
}

Using EdittextPreference for Goto search
sorry for my poor English. I want to use EditTextPreference in my bottom nav like the pic below, ![screenshot][1]

I have recycleview xml in my project with in many sub cardview layouts(which is scrollable) and I want to create item in the bottom nav which is called "Goto". When the "Goto" item is clicked i want it to pop-up like the screenshot. And when user enters a number(according to the cardviews i.e if the number of cardview is 40 user must enter 1-40) I want to search the cardview by its ID. Thank you and I hope u got it, If u have any questions let me know [1]: https://i.stack.imgur.com/grK8P.jpg

My xml format look like this. As you see in the blow since the cardviews are huge in number it is not cool to scroll all the way down that is why i need Goto item in the bottom nav to search it by its ID when the user click number in the EditTextPreference as u see in the screenshot. i.e The screenshot is not from my app
```
<LinearLayout>
 <LinearLayout>
  <androidx.cardview.widget.CardView>
    <RealtiveLayout>
       <Textview/>
    <RealtiveLayout>
 </androidx.cardview.widget.CardView>
 </LinearLayout>

 <LinearLayout>
  <androidx.cardview.widget.CardView>
    <RealtiveLayout>
       <Textview/>
    <RealtiveLayout>
 </androidx.cardview.widget.CardView>
 </LinearLayout>

<LinearLayout>
  <androidx.cardview.widget.CardView>
    <RealtiveLayout>
       <Textview/>
    <RealtiveLayout>
 </androidx.cardview.widget.CardView>
 </LinearLayout>

  <LinearLayout>
  <androidx.cardview.widget.CardView>
    <RealtiveLayout>
       <Textview/>
    <RealtiveLayout>
 </androidx.cardview.widget.CardView>
 </LinearLayout>
 
  ..
  ..

  ..
  ..
  many more..
```
How to get remaining time of the day in java?

I would like to calculate the time remaining for next day 00:00:00 from the current date time.

For e.g. time difference between 2022-05-07T05:49:41.883807900Z and 2022-05-08T00:00:00Z

Expected answer: 18:10:19 or 65419 (in seconds).

How can I achieve this with efficiently using java 8?
Hibernate handles id assigning instead of database

I have an auto-increment PK in a table and I want hibernate to handle id assigning instead of database. As my understanding the @GeneratedValue(strategy = GenerationType.IDENTITY) lets the database generate a new value with each insertion operation. So do we have any different solution to handle it?

How can I delete a row by its SKU instead of its ID?

I try to delete the row using the sku of the product. I'm using spring boot and angular. I got an error when I added the sku on my button like this one (click)="onDeleteProductBySku(deleteClick?.sku)" it said that the Property 'sku' does not exist on type '(product: Product) => void'.. On my command prompt, I got this error. How can I solve this problem?

Error: product/product.component.html:50:109 - error TS2339: Property 'sku' does not exist on type '(product: Product) => void'.

50 <button class="btn btn-outline-danger btn-sm me-2" (click)="onDeleteProductBySku(deleteClick?.sku)">Delete</button>
                                                                                                                                  
product/product.component.ts:12:16
    12   templateUrl: './product.component.html',
                      ~~~~~~~~~~~~~~~~~~~~~~~~~~
Error occurs in the template of component ProductComponent.

ProductsController.java --> This is working on the postman.

//Delete a product record using sku
//http://localhost:8080/products/deletebysku?sku=12345678

@DeleteMapping("/products/deletebysku")
@ResponseBody
private void deleteProductBySku(@RequestParam String sku){
    productsService.deleteProductBySku(sku);
}

product.component.ts

 public deleteProduct!: Product;

 public onDeleteProductBySku(sku: string): void {
    this.productServive.deleteProductBySku(sku).subscribe(
      (response: void) => {
        this.messageShow();
        console.log(response);
        this.getAllProduct();
      },
      (error: HttpErrorResponse) => {
        this.errorMessage(error.message);
      }
    );
 }

 public deleteClick(product: Product) {
   this.deleteProduct = product;
   console.log("delete by sku");
 }

product.service.ts

public deleteProductBySku(sku: string): Observable<void> {
  return this.http.delete<void>(`${this.apiServerUrl}/products/deletebysku?sku=${sku}`);
}

product.component.html

<button class="btn btn-outline-danger btn-sm me-2" (click)="onDeleteProductBySku(deleteClick?.sku)">Delete</button>

Multithreading using springboot

I’m new to multithreading and I want to know how to approach it for my code, currently files are getting generated and processed into fielder using single thread hence unable to handle bulk file generation abs this needs to be handled using multithreading . How do I approach this ? Using java 11 and xml format springboot approach .
best way to add a spring boot web application with JSPs to a docker container?
so i have a spring boot web application, it uses JSPs, and im supposed to put it in a container .
my question is what is the best way ? ive tried to copy the project and then run it there using a wmvn like so : dockerfile:
```
FROM openjdk:8-jdk-alpine
ADD . /input-webapp
WORKDIR /input-webapp
EXPOSE 8080:8080
ENTRYPOINT ./mvnw spring-boot:run
```
which works, but it takes a long time getting the dependencies and feels messy .

and ive tried to package it into a jar, and then copy the jar only, and run it : dockerfile:
```
FROM openjdk:8-jdk-alpine
ADD target/input-webapp-0.0.1-SNAPSHOT.jar input-webapp-0.0.1-SNAPSHOT.jar
EXPOSE 8080:8080
ENTRYPOINT ["java","-jar","input-webapp-0.0.1-SNAPSHOT.jar"]
```
but this way it cant see the JSPs, or at least i think this is the problem, as i get a 404.

so is there a better way ? can i copy the jsps plus the jar to make it work? thanks

build spring boot (mvnw) with docker can not use cache

Spring Boot Docker Experimental Features Docker 18.06 comes with some “experimental” features, including a way to cache build dependencies. To switch them on, you need a flag in the daemon (dockerd) and an environment variable when you run the client. With the experimental features, you get different output on the console, but you can see that a Maven build now only takes a few seconds instead of minutes, provided the cache is warm.

my dockerfile can not use cache.

dockerfile

# syntax=docker/dockerfile:experimental
FROM openjdk:8-jdk-alpine as build
WORKDIR /workspace/app

COPY mvnw .
COPY .mvn .mvn
COPY pom.xml .
COPY src src

RUN --mount=type=cache,target=/root/.m2 ./mvnw install -DskipTests -s .mvn/wrapper/settings.xml
RUN mkdir -p target/extracted && java -Djarmode=layertools -jar target/*.jar extract --destination target/extracted

FROM openjdk:8-jre-alpine
ENV TZ Asia/Shanghai
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
RUN addgroup -S spring && adduser -S spring -G spring
USER spring:spring

ARG EXTRACTED=/workspace/app/target/extracted
ARG JAVA_OPTS="-Xmx100m -Xms100m"

COPY --from=build ${EXTRACTED}/dependencies/ ./
COPY --from=build ${EXTRACTED}/spring-boot-loader/ ./
COPY --from=build ${EXTRACTED}/snapshot-dependencies/ ./
COPY --from=build ${EXTRACTED}/application/ ./

ENTRYPOINT ["sh", "-c","java ${JAVA_OPTS} org.springframework.boot.loader.JarLauncher"]

run shell

DOCKER_BUILDKIT=1 docker build -t org/spring-boot .

every time use many minutes

Sequence number, incorrect number
In a spring boot application, I have this entity

@Data @NoArgsConstructor @AllArgsConstructor @Entity public class User {
```
@Id
@GeneratedValue(generator="user_id_seq")
@SequenceGenerator(name="user_id_seq",sequenceName="user_id_seq", allocationSize=1)
Long id
 ...
```
}

In mariadb, when I check the sequence
```
CREATE OR REPLACE SEQUENCE `user_id_seq` start with 1 minvalue 1 maxvalue 9223372036854775806 increment by 1 cache 1000 nocycle ENGINE=InnoDB
```
In db, I have only 5 user.
```
select id from `user` u 
```
This query return

1002 1004 1005 2007 3001

Why it's not 1, 2, 3, 4, 5

Is it beaucause of the cache 1000?
Select only a set to improve perfomance
I search to know if a user have an active subscription
```
@Query("select case when count(u) > 0 then true else false end from User u where u.id=:userId and  current_date < u.subscriptionEndDate")
boolean userActiveSubscription(Long userId);
```
subscriptionEndDate use a localdate

Probably user object is queried, is there a way to limit data retrived to return true or false
How to throw exception when there is extra parameters in request body spring boot
In my last project, there was a requirement for throwing exceptions when the request body contains extra parameters.

If the request will be like
```
{
   "test":"body",
    "name":"HR 1",
    "location":"Location"
}
```
where test parameter is unnecessary and I've to return a response that should be like
```
{
    "timestamp": "2022-05-07T00:13:59.144657",
    "status": "500",
    "error": "Internal Server Error",
    "message": "test : must not be provided",
    "path": "/api/departments/HR"
}
```
I've shared the answer. How I handled it.

How to download an image from api in react without opening it?

I want to create a download button which will download image from api, I was able to do that but then got stuck in a problem . whenever I click on download button it does download the image but it also open the image in that page which makes it to leave the main page. I want it so that it won't open the image only download the image .

here is what I did

const download = (e) => {
    console.log(e.target.href);
    fetch(e.target.href, {
      method: "GET",
      headers: {},
    })
      .then((response) => {
        response.arrayBuffer().then(function (buffer) {
          const url = window.URL.createObjectURL(new Blob([buffer]));
          const link = document.createElement("a");
          link.href = url;
          link.setAttribute("download", "image.png"); //or any other extension
          document.body.appendChild(link);
          link.click();
        });
      })
      .catch((err) => {
        console.log(err);
      });
  };



<div className="row">
        <div className="col-sm-4 text-center">
          {quote?.map((items) => (
            <div class="card" style={{ width: "18rem;" }}>
              <img src={items.img} class="card-img-top" alt="..." />
              <div class="card-body">
                <h5 style={{ textTransform: "capitalize" }} class="card-title">
                  {items.name.replace(/_/g, " ")}
                </h5>
                <p class="card-text">{items.disc}</p>
                <Button
                  variant="outlined"
                  href={items.img}
                  onClick={ download }
                >
                  Download
                </Button>
              </div>
            </div>
          ))}
        </div>
      </div>

Image Downloader with Spring Boot

I am beginner... I have to write a program that should download an image from a URL (about 100 thousand) and store it in a database. How can I do this with Spring Boot With REST?? (Or with multithreading) I will be grateful for help.

Related questions

Java Spring Boot Download images from URL

See also questions close to this topic