Curl to Java Converter

Convert curl commands to Java code - Generate ready-to-use Java HttpClient code for API requests

Privacy Notice: This professional tool provides secure conversion to Java code with enterprise-grade privacy protection. We do not store any data you submit, ensuring complete confidentiality for your API development work.

Java HttpClient Code Generator

// Java HttpClient code will appear here
// Example:
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Duration;

public class HttpClientExample {
    public static void main(String[] args) throws Exception {
        HttpClient client = HttpClient.newBuilder()
                .version(HttpClient.Version.HTTP_2)
                .connectTimeout(Duration.ofSeconds(10))
                .build();
                
        String jsonBody = "{\"name\": \"test\"}";
        
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://api.example.com/data"))
                .header("Content-Type", "application/json")
                .POST(HttpRequest.BodyPublishers.ofString(jsonBody))
                .build();
                
        HttpResponse response = client.send(request, 
                HttpResponse.BodyHandlers.ofString());
                
        System.out.println(response.statusCode());
        System.out.println(response.body());
    }
}

Common curl Commands for Java API Testing

Here are some common curl commands that you can convert to Java code:

Basic GET request: curl https://api.example.com/users
POST with JSON data: curl -X POST -H "Content-Type: application/json" -d '{"name":"John","email":"[email protected]"}' https://api.example.com/users
PUT with authentication: curl -X PUT -H "Authorization: Bearer token123" -d '{"status":"active"}' https://api.example.com/users/1
DELETE request: curl -X DELETE https://api.example.com/users/1
Custom headers: curl -H "X-API-Key: abc123" -H "Accept: application/json" https://api.example.com/data

Java HttpClient Examples

Java's HttpClient library (introduced in Java 11) is a powerful and modern way to make HTTP requests. Here are some common Java HttpClient patterns:

File Upload with Java HttpClient

import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class FileUploadExample {
    public static void main(String[] args) throws IOException, InterruptedException {
        HttpClient client = HttpClient.newBuilder()
                .version(HttpClient.Version.HTTP_2)
                .build();
                
        Path path = Paths.get("document.pdf");
        String boundary = "----WebKitFormBoundary" + System.currentTimeMillis();
        String contentType = "multipart/form-data; boundary=" + boundary;
        
        // Create multipart form data
        String data = "--" + boundary + "\r\n" +
                "Content-Disposition: form-data; name=\"file\"; filename=\"" + path.getFileName() + "\"\r\n" +
                "Content-Type: application/pdf\r\n\r\n";
                
        byte[] fileData = Files.readAllBytes(path);
        byte[] requestBody = new byte[data.getBytes().length + fileData.length + ("\r\n--" + boundary + "--\r\n").getBytes().length];
        
        System.arraycopy(data.getBytes(), 0, requestBody, 0, data.getBytes().length);
        System.arraycopy(fileData, 0, requestBody, data.getBytes().length, fileData.length);
        System.arraycopy(("\r\n--" + boundary + "--\r\n").getBytes(), 0, requestBody, 
                data.getBytes().length + fileData.length, ("\r\n--" + boundary + "--\r\n").getBytes().length);
        
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://api.example.com/upload"))
                .header("Content-Type", contentType)
                .header("Authorization", "Bearer YOUR_TOKEN_HERE")
                .POST(HttpRequest.BodyPublishers.ofByteArray(requestBody))
                .build();
                
        HttpResponse response = client.send(request, 
                HttpResponse.BodyHandlers.ofString());
                
        System.out.println(response.body());
    }
}

Java HttpClient with Timeout and Error Handling

import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.time.Duration;

public class ErrorHandlingExample {
    public static void main(String[] args) {
        HttpClient client = HttpClient.newBuilder()
                .version(HttpClient.Version.HTTP_2)
                .connectTimeout(Duration.ofSeconds(5))
                .build();
                
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://api.example.com/data"))
                .timeout(Duration.ofSeconds(5))
                .GET()
                .build();
                
        try {
            HttpResponse response = client.send(request, 
                    HttpResponse.BodyHandlers.ofString());
                    
            int statusCode = response.statusCode();
            if (statusCode >= 200 && statusCode < 300) {
                System.out.println("Success: " + response.body());
            } else {
                System.out.println("Error: " + statusCode + " - " + response.body());
            }
        } catch (IOException e) {
            System.out.println("Connection error: " + e.getMessage());
        } catch (InterruptedException e) {
            System.out.println("Request interrupted: " + e.getMessage());
            Thread.currentThread().interrupt();
        } catch (Exception e) {
            System.out.println("Error making request: " + e.getMessage());
        }
    }
}

How to Use the Java HttpClient Converter

1. Basic Usage

Copy your curl command → Paste into the input box → Get converted Java HttpClient code

2. Java HttpClient Features

HTTP methods (GET, POST, PUT, DELETE, etc.)
Request headers in Java format
JSON and form data handling
Basic and token authentication
SSL verification options
Session handling with Java HttpClient

3. Advanced Java HttpClient Usage

Our converter supports complex curl commands and translates them to clean, efficient Java code using the HttpClient library

4. Converting curl Options to Java

Our tool handles these common curl options and converts them to appropriate Java HttpClient code:

-X, --request: Sets the HTTP method (GET, POST, PUT, etc.)
-H, --header: Adds HTTP headers to the request
-d, --data: Sends data in the request body
--data-binary: Sends binary data in the request body
-u, --user: Adds basic authentication
-k, --insecure: Disables SSL certificate verification
--connect-timeout: Sets connection timeout

Frequently Asked Questions about Java HttpClient

Q: What Java version is required for the generated code?

A: The generated Java HttpClient code requires Java 11 or higher. For older Java versions, consider using alternative HTTP clients like Apache HttpClient or OkHttp.

Q: Does the Java code handle error checking?

A: The basic generated code includes try/catch blocks for IOException and InterruptedException. For production code, you may want to add more specific error handling for different HTTP status codes.

Q: How can I process the response in Java?

A: The HttpClient library provides several BodyHandlers for processing responses. Use HttpResponse.BodyHandlers.ofString() for text responses, ofInputStream() for binary data, or ofByteArray() for raw bytes.

Q: Do I need to install any libraries to use the generated code?

A: No external libraries are required. The HttpClient is part of the Java standard library since Java 11. For JSON processing, you might want to add a library like Jackson or Gson.

Q: How do I convert a curl command with file upload to Java?

A: For file uploads in Java, you'll need to use multipart form data with HttpClient. Our converter handles curl commands with -F or --form options and generates the appropriate Java code.

Q: How do I handle cookies in Java HttpClient?

A: Java's HttpClient provides cookie handling through the HttpClient.Builder.cookieHandler() method. When you convert curl commands that include cookie handling (using -b or --cookie), our tool generates Java code that properly manages cookies.

Q: What's the difference between using curl and Java HttpClient for API testing?

A: While curl is excellent for quick command-line API testing, Java HttpClient provides a programmatic approach that integrates with your Java applications. Converting curl to Java helps bridge the gap between testing and implementation in Java development.

Curl Command Reference for Java API Testing

Understanding curl commands is essential for effective API testing with Java. Here's a quick reference of common curl options that our converter supports:

Basic curl Syntax

curl [options] [URL]

Common curl Options

-X, --request METHOD: Specify request method (GET, POST, PUT, DELETE, etc.)
-H, --header LINE: Add header to the request
-d, --data DATA: Send data in POST request
-F, --form CONTENT: Submit form data
-u, --user USER:PASSWORD: Server user and password
-k, --insecure: Allow insecure server connections
-I, --head: Show document info only
-v, --verbose: Make the operation more verbose
-s, --silent: Silent mode
--connect-timeout SECONDS: Maximum time for connection

Converting Complex curl Commands

Our Java converter handles complex curl commands including multiple headers, authentication, data payloads, and various options. Simply paste your curl command and get clean, modern Java code using the HttpClient library.

Java HttpClient Best Practices

When working with the Java HttpClient library, follow these best practices for efficient and secure API interactions:

1. Reuse HttpClient Instances

import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.net.URI;

public class HttpClientReuseExample {
    // Create a single HttpClient instance for the application
    private static final HttpClient httpClient = HttpClient.newBuilder()
            .version(HttpClient.Version.HTTP_2)
            .build();
            
    public static void main(String[] args) throws Exception {
        // First request
        HttpRequest request1 = HttpRequest.newBuilder()
                .uri(URI.create("https://api.example.com/users"))
                .GET()
                .build();
        HttpResponse response1 = httpClient.send(request1, 
                HttpResponse.BodyHandlers.ofString());
                
        // Second request (uses same client)
        HttpRequest request2 = HttpRequest.newBuilder()
                .uri(URI.create("https://api.example.com/products"))
                .GET()
                .build();
        HttpResponse response2 = httpClient.send(request2, 
                HttpResponse.BodyHandlers.ofString());
    }
}

2. Implement Proper Error Handling

import java.io.IOException;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.net.http.HttpTimeoutException;

public class ErrorHandlingBestPractice {
    public static void main(String[] args) {
        HttpClient client = HttpClient.newHttpClient();
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://api.example.com/data"))
                .GET()
                .build();
                
        try {
            HttpResponse response = client.send(request, 
                    HttpResponse.BodyHandlers.ofString());
                    
            switch (response.statusCode()) {
                case 200:
                case 201:
                    System.out.println("Success: " + response.body());
                    break;
                case 400:
                    System.out.println("Bad request: " + response.body());
                    break;
                case 401:
                case 403:
                    System.out.println("Authentication error: " + response.statusCode());
                    break;
                case 404:
                    System.out.println("Resource not found");
                    break;
                case 500:
                case 503:
                    System.out.println("Server error: " + response.statusCode());
                    break;
                default:
                    System.out.println("Unexpected status: " + response.statusCode());
            }
        } catch (HttpTimeoutException e) {
            System.out.println("Request timed out: " + e.getMessage());
        } catch (IOException e) {
            System.out.println("Network error: " + e.getMessage());
        } catch (InterruptedException e) {
            System.out.println("Request interrupted");
            Thread.currentThread().interrupt();
        }
    }
}

3. Use Asynchronous Requests for Better Performance

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.util.concurrent.CompletableFuture;

public class AsyncRequestExample {
    public static void main(String[] args) {
        HttpClient client = HttpClient.newHttpClient();
        
        HttpRequest request = HttpRequest.newBuilder()
                .uri(URI.create("https://api.example.com/data"))
                .GET()
                .build();
                
        CompletableFuture> futureResponse = 
                client.sendAsync(request, HttpResponse.BodyHandlers.ofString());
                
        futureResponse
            .thenApply(HttpResponse::body)
            .thenAccept(System.out::println)
            .exceptionally(e -> {
                System.err.println("Error: " + e.getMessage());
                return null;
            });
            
        // Do other work while the request is processing
        System.out.println("Request sent asynchronously...");
        
        // Wait for the request to complete if needed
        futureResponse.join();
    }
}

Curl to Java Converter

Java HttpClient Code Generator

Common curl Commands for Java API Testing

Java HttpClient Examples

File Upload with Java HttpClient

Java HttpClient with Timeout and Error Handling

How to Use the Java HttpClient Converter

1. Basic Usage

2. Java HttpClient Features

3. Advanced Java HttpClient Usage

4. Converting curl Options to Java

Frequently Asked Questions about Java HttpClient

Q: What Java version is required for the generated code?

Q: Does the Java code handle error checking?

Q: How can I process the response in Java?

Q: Do I need to install any libraries to use the generated code?

Q: How do I convert a curl command with file upload to Java?

Q: How do I handle cookies in Java HttpClient?

Q: What's the difference between using curl and Java HttpClient for API testing?

Curl Command Reference for Java API Testing

Basic curl Syntax

Common curl Options

Converting Complex curl Commands

Java HttpClient Best Practices

1. Reuse HttpClient Instances

2. Implement Proper Error Handling

3. Use Asynchronous Requests for Better Performance

Convert curl to Other Languages