Book Image

The Java Workshop

By : David Cuartielles, Andreas Göransson, Eric Foster-Johnson
3 (1)
Book Image

The Java Workshop

3 (1)
By: David Cuartielles, Andreas Göransson, Eric Foster-Johnson

Overview of this book

Java is a versatile, popular programming language used across a wide range of industries. Learning how to write effective Java code can take your career to the next level, and The Java Workshop will help you do just that. This book is designed to take the pain out of Java coding and teach you everything you need to know to be productive in building real-world software. The Workshop starts by showing you how to use classes, methods, and the built-in Collections API to manipulate data structures effortlessly. You’ll dive right into learning about object-oriented programming by creating classes and interfaces and making use of inheritance and polymorphism. After learning how to handle exceptions, you’ll study the modules, packages, and libraries that help you organize your code. As you progress, you’ll discover how to connect to external databases and web servers, work with regular expressions, and write unit tests to validate your code. You’ll also be introduced to functional programming and see how to implement it using lambda functions. By the end of this Workshop, you’ll be well-versed with key Java concepts and have the knowledge and confidence to tackle your own ambitious projects with Java.
Table of Contents (20 chapters)

Creating HTTP POST Requests

POST (and PUT) requests send data to the server. For a POST request, you need to turn on the output mode of HttpUrlConnection and set the content type:

connection.setRequestMethod("POST");
connection.setRequestProperty("Content-Type", "application/json");
connection.setDoOutput(true);

Next, to upload the data, here assumed to be a String, use code like the following:

DataOutputStream out =
        new DataOutputStream( connection.getOutputStream() );
out.writeBytes(content);
out.flush();
out.close();

With web browsing, most POST requests send form data. From Java programs, however, you are more likely to upload JSON or XML data with POST and PUT requests. Once you upload the data, your program should read the response, especially to see whether the request was successful.

Exercise 3: Sending JSON Data with POST Requests

In this exercise, we'll send a small JSON object...