In this tutorial, we’ll explore several libraries for reading an HTTP response body as a string in Java. Since the first versions, Java provided the HttpURLConnection<\/em><\/a> API. This includes only basic features and is known for not being very user-friendly.<\/p>\n With the release of JDK 11, Java introduced the new and improved HttpClient<\/a> <\/em>API to handle HTTP communication. We’ll cover these libraries, and we’ll check some alternatives such as the Apache HttpClient<\/a> and the Spring Rest Template<\/a>.<\/p>\n As we mentioned before, HttpClient<\/em><\/a> was added to Java 11. It allows us to access resources over the network. But, unlike HttpURLConnection<\/em>, HttpClient<\/em> supports HTTP\/1.1 and HTTP\/2<\/strong>. Moreover, it provides both synchronous and asynchronous request types<\/strong>.<\/p>\n HttpClient<\/em> offers a modern API with a lot of flexibility and powerful features. Mainly, this API consists of three core classes: HttpClient<\/em>, HttpRequest<\/em>, and HttpResponse<\/em>.<\/p>\n HttpResponse<\/em> describes the result of an HttpRequest<\/em> call. HttpResponse<\/em> isn’t created directly and is made available when the body has been fully received.<\/strong><\/p>\n To read a response body as a String,<\/em> we’ll first need to create simple client and request objects:<\/p>\n Then, we simply use BodyHandlers<\/em> and call the method ofString()<\/em> to return the response:<\/p>\n HttpURLConnection<\/em><\/a> is a lightweight HTTP client used to access resources via the HTTP or HTTPS protocol and allows us to create an InputStream<\/em>. Once we obtain the InputStream,<\/em> we can read it like a normal local file.<\/p>\n In Java, the main classes we can use to access the Internet are the java.net.URL<\/em> class and the java.net.HttpURLConnection<\/em> class. First, we’ll use the URL<\/em> class to point to a web resource. Then, we can access it by using the HttpURLConnection<\/em> class.<\/p>\n To get the response body from a URL<\/em> as a String<\/em>, we should first create an HttpURLConnection<\/em><\/strong> using our URL<\/em>:<\/p>\n The new URL(DUMMY_URL).openConnection()<\/em> returns a HttpURLConnection<\/em>. This object allows us to add headers or checking the response code.<\/p>\n Next, let’s get the InputStream<\/em> from the connection<\/em><\/strong> object:<\/p>\n Finally, we need to convert the InputStream<\/em> to a String<\/em><\/a><\/strong>.<\/p>\n In this section, we’ll see how to use the Apache HttpClient<\/em><\/a>\u00a0for reading an HTTP response body as a string.<\/p>\n To use this library, we’ll need to add its dependency to our Maven project:<\/p>\n We can retrieve and send data via the CloseableHttpClient<\/em> class<\/strong>. To create an instance of it with default configuration we can use the HttpClients.createDefault()<\/em>.<\/p>\n CloseableHttpClient<\/em> provides an execute<\/em> method to send and receive data. This method uses a parameter of type HttpUriRequest<\/em>, which has many subclasses including HttpGet<\/em> and HttpPost<\/em>.<\/p>\n Let’s first create an HttpGet<\/em> object<\/strong>:<\/p>\n Second, let’s create the client<\/strong>:<\/p>\n Third, we retrieve the response object<\/strong> from the result of the execute<\/em> method:<\/p>\n Finally, we return the response body by converting the response entity to a String<\/em><\/strong>:<\/p>\n In this section, we’ll see how to use Spring RestTemplate<\/em><\/a> for reading an HTTP response body as a string.<\/p>\n The RestTemplate<\/em> class is an essential tool provided by Spring that offers a simple template for making client-side HTTP operations<\/strong> over underlying HTTP client libraries such as the JDK HttpURLConnection<\/em>, Apache HttpClient<\/em>, and others.<\/p>\n RestTemplate<\/em> provides some useful methods<\/a> for creating HTTP requests and handling responses.<\/p>\n We can use this library by first adding some dependencies to our Maven project:<\/p>\n To make a web request and return the response body as a string, let’s first create an instance of RestTemplate<\/em><\/strong>:<\/p>\n Second, we get the response object by calling the method getForObject()<\/em>, passing in the URL and desired response type<\/strong>\u00a0\u2014 we’ll use String.class<\/em> in our example:<\/p>\n In this article, we\u2019ve seen how to use several libraries for reading an HTTP response body as a String<\/em>.<\/p>\n As usual, the complete code is available over on GitHub<\/a>.<\/p>\n The post Reading an HTTP Response Body as a String in Java<\/a> first appeared on Baeldung<\/a>.<\/p>\n Explore several options for reading an HTTP response body as a string in Java<\/p>\n The post Reading an HTTP Response Body as a String in Java<\/a> first appeared on Baeldung<\/a>.<\/p>\n2. HttpClient<\/em><\/h2>\n
HttpClient client = HttpClient.newHttpClient();\r\nHttpRequest request = HttpRequest.newBuilder()\r\n .uri(URI.create(DUMMY_URL))\r\n .build();<\/code><\/pre>\nHttpResponse response = client.send(request, HttpResponse.BodyHandlers.ofString());<\/code><\/pre>\n3. HttpURLConnection<\/em><\/h2>\n
HttpURLConnection connection = (HttpURLConnection) new URL(DUMMY_URL).openConnection();<\/code><\/pre>\nInputStream inputStream = connection.getInputStream();<\/code><\/pre>\n4. Apache HttpClient<\/em><\/h2>\n
<dependency>\r\n <groupId>org.apache.httpcomponents<\/groupId>\r\n <artifactId>httpclient<\/artifactId>\r\n <version>4.5.12<\/version>\r\n<\/dependency><\/code><\/pre>\nHttpGet request = new HttpGet(DUMMY_URL);<\/code><\/pre>\nCloseableHttpClient client = HttpClients.createDefault();<\/code><\/pre>\nCloseableHttpResponse response = client.execute(request);<\/code><\/pre>\nHttpEntity entity = response.getEntity();\r\nString result = EntityUtils.toString(entity);<\/code><\/pre>\n5. Spring RestTemplate<\/em><\/h2>\n
<dependency>\r\n <groupId>org.springframework.boot<\/groupId>\r\n <artifactId>spring-boot-starter-web<\/artifactId>\r\n <version>${spring-boot.version}<\/version>\r\n<\/dependency>\r\n<dependency>\r\n <groupId>org.springframework.boot<\/groupId>\r\n <artifactId>spring-boot-starter-test<\/artifactId>\r\n <version>${spring-boot.version}<\/version>\r\n <scope>test<\/scope>\r\n<\/dependency><\/code><\/pre>\nRestTemplate restTemplate = new RestTemplate();<\/code><\/pre>\nString response = restTemplate.getForObject(DUMMY_URL, String.class);<\/code><\/pre>\n6. Conclusion<\/h2>\n
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