La transferencia de estado representacional (REST) es un estilo arquitectónico que define un conjunto de restricciones que se utilizarán para crear servicios web. REST API es una forma de acceder a los servicios web de una manera simple y flexible sin tener ningún procesamiento. Spring MVC es un marco Web MVC para crear aplicaciones web. Es un módulo Spring igual que Spring Boot, Spring-Security, etc. El término MVC significa arquitectura Model-View-Controller. Las llamadas API REST se usan ampliamente hoy en día para obtener información diversa como el clima, el código postal, la criptomoneda, los detalles de la universidad, etc. En este artículo, intentemos obtener los detalles de la serie de televisión a través de
http://api.tvmaze.com/search/shows?q=<any TV Serial Name>
Ejemplo:
https://api.tvmaze.com/search/shows?q=mahabharata
Salida JSON:
[
{
"score": 0.6494496,
"show": {
"id": 60856,
"url": "https://www.tvmaze.com/shows/60856/the-mahabharata",
"name": "The Mahabharata",
"type": "Scripted",
"language": "English",
"genres": [],
"status": "Ended",
"runtime": null,
"averageRuntime": null,
"premiered": "1990-03-10",
"ended": "1990-03-24",
"officialSite": null,
"schedule": {
"time": "",
"days": []
},
"rating": {
"average": null
},
"weight": 0,
"network": {
"id": 269,
"name": "Star Plus",
"country": {
"name": "India",
"code": "IN",
"timezone": "Asia/Kolkata"
},
"officialSite": null
},
"webChannel": null,
"dvdCountry": null,
"externals": {
"tvrage": null,
"thetvdb": 213551,
"imdb": "tt0097810"
},
"image": {
"medium": "https://static.tvmaze.com/uploads/images/medium_portrait/398/996547.jpg",
"original": "https://static.tvmaze.com/uploads/images/original_untouched/398/996547.jpg"
},
"summary": null,
"updated": 1646508699,
"_links": {
"self": {
"href": "https://api.tvmaze.com/shows/60856"
},
"previousepisode": {
"href": "https://api.tvmaze.com/episodes/2289706"
}
}
}
},
{
"score": 0.5061876,
"show": {
"id": 5016,
"url": "https://www.tvmaze.com/shows/5016/mahabharat",
"name": "Mahabharat",
"type": "Scripted",
"language": "Hindi",
"genres": [
"Drama",
"History"
],
"status": "Ended",
"runtime": 20,
"averageRuntime": 20,
"premiered": "2013-09-16",
"ended": "2014-08-16",
"officialSite": "http://www.hotstar.com/#!/mahabharat-435-s",
"schedule": {
"time": "20:30",
"days": [
"Monday",
"Tuesday",
"Wednesday",
"Thursday",
"Friday",
"Saturday",
"Sunday"
]
},
"rating": {
"average": null
},
"weight": 47,
"network": {
"id": 269,
"name": "Star Plus",
"country": {
"name": "India",
"code": "IN",
"timezone": "Asia/Kolkata"
}
},
"webChannel": null,
"dvdCountry": null,
"externals": {
"tvrage": 46350,
"thetvdb": 273350,
"imdb": "tt3212600"
},
"image": {
"medium": "https://static.tvmaze.com/uploads/images/medium_portrait/21/54241.jpg",
"original": "https://static.tvmaze.com/uploads/images/original_untouched/21/54241.jpg"
},
"summary": "<p>The story of the throne of Hastinapura, the kingdom ruled by the Kuru clan. The two collateral branches of the family that participate in the struggle of the throne of Hastinapura are the Kaurava and the Pandava. Although the Kaurava is the senior branch of the family, Duryodhana, the eldest Kaurava, is younger than Yudhisthira, the eldest Pandava. Both Duryodhana and Yudhisthira claim to be first in line to inherit the throne. The struggle culminates in the great battle of Kurukshetra, in which the Pandavas are ultimately victorious. The battle produces complex conflicts of kinship and friendship, instances of family loyalty and duty taking precedence over what is right, as well as the converse.</p>",
"updated": 1604823863,
"_links": {
"self": {
"href": "https://api.tvmaze.com/shows/5016"
},
"previousepisode": {
"href": "https://api.tvmaze.com/episodes/314287"
}
}
}
},
{
"score": 0.42338097,
"show": {
"id": 16607,
"url": "https://www.tvmaze.com/shows/16607/mahabharat",
"name": "Mahabharat",
"type": "Scripted",
"language": "Hindi",
"genres": [
"Drama"
],
"status": "Ended",
"runtime": 45,
"averageRuntime": 45,
"premiered": "1988-10-02",
"ended": "1990-07-15",
"officialSite": null,
"schedule": {
"time": "",
"days": [
"Sunday"
]
},
"rating": {
"average": null
},
"weight": 17,
"network": {
"id": 1093,
"name": "DD National",
"country": {
"name": "India",
"code": "IN",
"timezone": "Asia/Kolkata"
}
},
"webChannel": null,
"dvdCountry": null,
"externals": {
"tvrage": null,
"thetvdb": 84349,
"imdb": "tt0158417"
},
"image": {
"medium": "https://static.tvmaze.com/uploads/images/medium_portrait/55/138442.jpg",
"original": "https://static.tvmaze.com/uploads/images/original_untouched/55/138442.jpg"
},
"summary": "<p><b>Mahabharat</b> is a successful Indian television series based on the ancient Indian epic Mahabharata. The 94-episode series originally ran from 1988 to 1990. It was produced by B. R. Chopra and directed by his son, Ravi Chopra.</p>",
"updated": 1573325769,
"_links": {
"self": {
"href": "https://api.tvmaze.com/shows/16607"
},
"previousepisode": {
"href": "https://api.tvmaze.com/episodes/762035"
}
}
}
}
]
Usando Spring Framework , intentemos extraer la API REST y representarla en las páginas.
Implementación paso a paso
Estructura del proyecto:
pom.xml:
XML
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.TVShow.TVShow_Rest_API</groupId>
<artifactId>TVShow_Rest_API</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>TVShow</name>
<url>http://maven.apache.org</url>
<properties>
<failOnMissingWebXml>false</failOnMissingWebXml>
<spring-version>5.1.0.RELEASE</spring-version>
</properties>
<dependencies>
<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>${spring-version}</version>
</dependency>
<!-- Required for spring-test -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
<version>${spring-version}</version>
</dependency>
<!-- JSTL Dependency -->
<dependency>
<groupId>javax.servlet.jsp.jstl</groupId>
<artifactId>javax.servlet.jsp.jstl-api</artifactId>
<version>1.2.1</version>
</dependency>
<dependency>
<groupId>taglibs</groupId>
<artifactId>standard</artifactId>
<version>1.1.2</version>
</dependency>
<!-- Servlet Dependency -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>3.1.0</version>
<scope>provided</scope>
</dependency>
<!-- JSP Dependency -->
<dependency>
<groupId>javax.servlet.jsp</groupId>
<artifactId>javax.servlet.jsp-api</artifactId>
<version>2.3.1</version>
<scope>provided</scope>
</dependency>
<!-- As REST API is extracted, this is required -->
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.6</version>
</dependency>
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.5</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<finalName>TVShow</finalName>
<sourceDirectory>src/main/java</sourceDirectory>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.5.1</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>3.3.2</version>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>tomcat-maven-plugin</artifactId>
<version>1.0-beta-1</version>
</plugin>
</plugins>
</build>
</project>
índice.jsp:
Esta es la página que se representa cuando el proyecto se implementa en tomcat
Java
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>TVShow</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.0/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.0/js/bootstrap.min.js"></script>
// for making the page styles are applied
<style type="text/css">
.main-form, .profile-area {
width: 500px;
}
.main-form {
margin: 50px auto 0px;
}
.profile-area {
margin: 10px auto;
}
.main-form section, .profile-area section {
margin-bottom: 15px;
background: #097969;
box-shadow: 0px 2px 2px rgba(0, 0, 0, 0.3);
color: white;
}
.main-form section {
padding: 30px;
}
.profile-area section {
padding: 30px 30px 30px;
}
.profile-area section > div {
text-align: center;
}
.main-form h3 {
margin: 0 0 15px;
}
.form-control, .btn {
min-height: 38px;
border-radius: 2px;
}
.btn {
font-size: 15px;
font-weight: bold;
}
.hideElement {
display: none;
}
</style>
</head>
<body>
<div class="main-form" id="main-form">
<section>
<div class="form-group">
// We need to input the search string in this box
<input id="searchStr" type="text" class="form-control" placeholder="Enter TVShow name here..." required="required">
</div>
<div class="form-group">
<button onclick="loadData()" class="btn btn-primary btn-block">Find TVShow Details</button>
</div>
</section>
</div>
<div class="profile-area hideElement" id="profile-area">
<section>
<div id="loader" class="hideElement">
<div class="spinner-border" role="status">
<span class="sr-only">Loading...</span>
</div>
</div>
<div id="profile" class="hideElement">
<br><br>
// parsed json object details are displayed here
<p><strong>TVShowScore : </strong><span id="scores"></span></p>
<p><strong>TVShow URL : </strong><span id="url"></span></p>
<p><strong>IMDB : </strong><span id="imdb"></span></p>
</div>
</section>
</div>
</body>
<script>
function loadData() {
document.getElementById("profile-area").classList.remove("hideElement");
document.getElementById("loader").classList.remove("hideElement");
document.getElementById("profile").classList.add("hideElement");
var searchStr = document.getElementById("searchStr").value;
if(searchStr != "" && searchStr != null ) {
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
var jsonResponse = JSON.parse(this.responseText);
document.getElementById("scores").innerHTML = jsonResponse.scores;
document.getElementById("url").innerHTML = jsonResponse.url;
document.getElementById("imdb").innerHTML = jsonResponse.imdb;
document.getElementById("loader").classList.add("hideElement");
document.getElementById("profile").classList.remove("hideElement");
}
};
// GET method which redirects the jsp to connect to
// the servlet with the search string
xhttp.open("GET", "getTVShowDetailsBySearchString?searchStr="+ searchStr, true);
xhttp.send();
console.log("done");
} else {
console.log("Enter search string to check...")
}
}
</script>
</html>
Producción:
Al ingresar cualquier nombre de TVShow en el cuadro de entrada, obtendremos los detalles a continuación.
Proceso de ejecución:
Desde la página JSP, se invoca un método «GET» con la string de búsqueda y se redirige a la clase Spring Controller, donde se encuentra la URL de la API REST, http://api.tvmaze.com/search/shows?q=<searchString > se invoca y creará la array JSON como se indicó anteriormente, a partir de eso, estamos tomando
"score", "url" and "imdb" values alone Example: "score": 0.42338097, "url": "https://www.tvmaze.com/shows/16607/mahabharat", "imdb": "tt0158417"
En realidad, en esta página, hemos recuperado solo TVShowScore, TVShow URL e IMDB solo. Pero podemos obtener todos los demás detalles que están disponibles en JSON. El código requerido para recuperar los datos y analizar la salida JSON es el siguiente. Importantes archivos necesarios para lograr el flujo
AppConfig.java:
Java
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import org.springframework.web.servlet.view.JstlView;
@Configuration
@EnableWebMvc
@ComponentScan(basePackages = { "com.TVShow.TVShow_Rest_API" })
public class AppConfig {
@Bean
public InternalResourceViewResolver resolver() {
InternalResourceViewResolver resolver = new InternalResourceViewResolver();
resolver.setViewClass(JstlView.class);
resolver.setPrefix("/");
resolver.setSuffix(".jsp");
return resolver;
}
}
SpringMvcDispatcherServletInitializer.java:
Java
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
public class SpringMvcDispatcherServletInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
@Override
protected Class<?>[] getRootConfigClasses() {
return null;
}
@Override
protected Class<?>[] getServletConfigClasses() {
return new Class[] { AppConfig.class };
}
@Override
protected String[] getServletMappings() {
return new String[] { "/" };
}
}
TVShowController.java:
Java
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.StringTokenizer;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import com.google.gson.Gson;
import com.google.gson.JsonArray;
import com.google.gson.JsonElement;
import com.google.gson.JsonObject;
@Controller
public class TVShowController {
@RequestMapping("/getTVShowDetailsBySearchString")
public @ResponseBody
JsonObject getTVShowDetailsBySearchString(String searchStr) throws IOException {
// According to the search string, JSONArray
// or JSON Object is constructed.
// In our case, it is producing JSONArray
JsonArray jsonArray = new JsonArray();
jsonArray = getTVShowDetailsBySearchStr(searchStr);
JsonObject finalJsonObject = new JsonObject();
ArrayList scoreList = new ArrayList();
ArrayList showUrlList = new ArrayList();
ArrayList showUrlLinks = new ArrayList();
ArrayList telecastedList = new ArrayList();
ArrayList imdbList = new ArrayList();
Iterator<JsonElement> objectIterator = jsonArray.iterator();
// Iterating
while(objectIterator.hasNext()) {
JsonElement object = objectIterator.next();
JsonObject jObj = object.getAsJsonObject();
// We have to get the score and
// replace the special characters
scoreList.add(jObj.get("score").toString().replaceAll("^\"|\"$", ""));
// Similarly show
showUrlList.add(jObj.get("show").toString().replaceAll("^\"|\"$", ""));
}
for (int i = 0;i < showUrlList.size();i++) {
StringTokenizer jsonTokenizer = new StringTokenizer(showUrlList.get(i).toString(),",");
String expectedTag = null;
int idx = 0;
while (jsonTokenizer.hasMoreTokens()) {
expectedTag = jsonTokenizer.nextToken();
if (expectedTag.contains("url")) {
showUrlLinks.add(expectedTag.substring(7,expectedTag.length()-1).toString());
}
if (expectedTag.contains("timezone")) {
telecastedList.add(expectedTag.substring(12,expectedTag.length()-3).toString());
}
if (expectedTag.contains("imdb")) {
imdbList.add(expectedTag.substring(8,expectedTag.length()-2).toString());
}
}
}
finalJsonObject.addProperty("scores", scoreList.toString());
finalJsonObject.addProperty("scoresize", scoreList.size());
finalJsonObject.addProperty("url", showUrlLinks.toString());
finalJsonObject.addProperty("urlsize", showUrlLinks.size());
finalJsonObject.addProperty("timezone", telecastedList.toString());
finalJsonObject.addProperty("imdb", imdbList.toString());
finalJsonObject.addProperty("imdbsize", imdbList.size());
// After retrieving the elements,
// in an object , all are constructed
return finalJsonObject;
}
private JsonArray getTVShowDetailsBySearchStr(String searchString) throws IOException {
StringBuilder responseData = new StringBuilder();
JsonArray jsonArray = null;
URL url = null;
// http://api.tvmaze.com/search/shows?q=<searchstring>
// is the url to access the TV show details
url = new URL("http://api.tvmaze.com/search/shows?q=" + searchString);
HttpURLConnection con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("GET");
con.setRequestProperty("User-Agent", "Mozilla/5.0");
int responseCode = con.getResponseCode();
System.out.println("\nSending 'GET' request to URL : " + url);
// System.out.println("Response Code : " + responseCode);
try (BufferedReader in = new BufferedReader(
new InputStreamReader(con.getInputStream()))) {
String line;
while ((line = in.readLine()) != null) {
responseData.append(line);
}
// It is getting converted to
// JSONArray by means of below code
jsonArray = new Gson().fromJson(responseData.toString(), JsonArray.class);
}
return jsonArray;
}
}
Conclusión
Al usar Spring-webmvc, podemos obtener los detalles de las llamadas a la API REST. Lo anterior es un excelente ejemplo de ello. Del mismo modo, hay tantas llamadas API REST de código abierto disponibles. Eso significa que podemos recuperar los datos usándolos. Algunos ejemplos de llamadas API REST de código abierto.
|
Nombre de la API |
Descripción |
URL de muestra |
|---|---|---|
| CoinBase | Códigos de moneda y nombres | https://api.coinbase.com/v2/currencies |
| ExchangeRate-API | Los tipos de cambio | https://open.er-api.com/v6/latest/USD |
| WeatherDB | Datos del tiempo | https://weatherdbi.herokuapp.com/data/weather/londres |
Publicación traducida automáticamente
Artículo escrito por priyarajtt y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA