Convert HTML to PDF from raw HTML in Java with Netty

In this guide, we'll show you how to convert raw HTML to PDF using Java and the Netty library.

Converting raw HTML content to PDF is useful when you have HTML content that isn't hosted on a web server.

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.*;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.http.*;
import io.netty.util.CharsetUtil;

// You can get an API key at https://pdfshift.io
String apiKey = "sk_xxxxxxxxxxxx";

EventLoopGroup group = new NioEventLoopGroup();
try {
    Bootstrap b = new Bootstrap();
    b.group(group)
        .channel(NioSocketChannel.class)
        .handler(new ChannelInitializer<SocketChannel>() {
            @Override
            public void initChannel(SocketChannel ch) {
                ChannelPipeline p = ch.pipeline();
                p.addLast(new HttpClientCodec());
                p.addLast(new HttpObjectAggregator(1024 * 1024));
            }
        });

    Channel ch = b.connect("api.pdfshift.io", 443).sync().channel();

    FullHttpRequest request = new DefaultFullHttpRequest(
        HttpVersion.HTTP_1_1, HttpMethod.POST, "/v3/convert/pdf");
    
    request.headers().set(HttpHeaderNames.HOST, "api.pdfshift.io");
    request.headers().set("X-API-Key", apiKey);
    request.headers().set(HttpHeaderNames.CONTENT_TYPE, "application/json");
    
    String payload = "{\n" +
        "  \"source\": \"<html><body><h1>Hello World</h1></body></html>\"\n" +
        "}";
    
    request.content().writeBytes(payload.getBytes(CharsetUtil.UTF_8));
    request.headers().setInt(HttpHeaderNames.CONTENT_LENGTH, request.content().readableBytes());

    ChannelFuture f = ch.writeAndFlush(request);
    f.addListener(ChannelFutureListener.CLOSE);
    
    // Handle response and save PDF...
    
    System.out.println("The PDF document was generated and saved to result.pdf");
} finally {
    group.shutdownGracefully();
}

This allows you to convert HTML content directly to PDF without needing a URL.

For further details on the source property and its usage, please refer to our dedicated documentation.

We hope this guide was helpful. If you have any questions or noticed any issues on the code above,
feel free to drop us a line.