使用RESTful Web服務



本章將詳細討論如何使用jQuery AJAX使用RESTful Web服務。

建立一個簡單的Spring Boot Web應用程式,並編寫一個控制器類檔案,用於重定向到用於使用RESTful Web服務的HTML檔案。

我們需要在構建配置檔案中新增Spring Boot啟動器Thymeleaf和Web依賴項。

對於Maven使用者,請在pom.xml檔案中新增以下依賴項。

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>

<dependency>
   <groupId>org.springframework.boot</groupId>
   <artifactId>spring-boot-starter-web</artifactId>
</dependency>

對於Gradle使用者,請在build.gradle檔案中新增以下依賴項:

compile group: ‘org.springframework.boot’, name: ‘spring-boot-starter-thymeleaf’
compile(‘org.springframework.boot:spring-boot-starter-web’)

@Controller類檔案的程式碼如下所示:

@Controller
public class ViewController {
}

您可以定義Request URI方法以重定向到HTML檔案,如下所示:

@GetMapping("/view-products")
public String viewProducts() {
   return "view-products";
}
@GetMapping("/add-products")
public String addProducts() {
   return "add-products";
}

此API **https://:8080/products**應返回如下所示的JSON響應:

[
   {
      "id": "1",
      "name": "Honey"
   },
   {
      "id": "2",
      "name": "Almond"
   }
]

現在,在類路徑中的templates目錄下建立一個view-products.html檔案。

在HTML檔案中,我們添加了jQuery庫,並編寫了在頁面載入時使用RESTful Web服務的程式碼。

<script src = "https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>

<script>
$(document).ready(function(){
   $.getJSON("https://:8080/products", function(result){
      $.each(result, function(key,value) {
         $("#productsJson").append(value.id+" "+value.name+" ");
      }); 
   });
});
</script>

POST方法和此URL **https://:8080/products**應包含以下請求正文和響應正文。

請求正文的程式碼如下所示:

{
   "id":"3",
   "name":"Ginger"
}

響應正文的程式碼如下所示:

Product is created successfully

現在,在類路徑中的templates目錄下建立add-products.html檔案。

在HTML檔案中,我們添加了jQuery庫,並編寫了單擊按鈕時將表單提交到RESTful Web服務的程式碼。

<script src = "https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script>
   $(document).ready(function() {
      $("button").click(function() {
         var productmodel = {
            id : "3",
            name : "Ginger"
         };
         var requestJSON = JSON.stringify(productmodel);
         $.ajax({
            type : "POST",
            url : "https://:8080/products",
            headers : {
               "Content-Type" : "application/json"
            },
            data : requestJSON,
            success : function(data) {
               alert(data);
            },
            error : function(data) {
            }
         });
      });
   });
</script>

完整的程式碼如下所示。

pom.xml

<?xml version="1.0" encoding="UTF-8"?>
   <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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>3.3.3</version>
      <relativePath/> <!-- lookup parent from repository -->
   </parent>
   <groupId>com.tutorialspoint</groupId>
   <artifactId>demo</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>demo</name>
   <description>Demo project for Spring Boot</description>
   <url/>
   <licenses>
      <license/>
   </licenses>
   <developers>
      <developer/>
   </developers>
   <scm>
      <connection/>
      <developerConnection/>
      <tag/>
      <url/>
   </scm>
   <properties>
      <java.version>21</java.version>
   </properties>
   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-web</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-test</artifactId>
         <scope>test</scope>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-thymeleaf</artifactId>
      </dependency>
   </dependencies>
   <build>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
         </plugin>
      </plugins>
   </build>
</project>

Gradle – build.gradle的程式碼如下所示:

build.gradle

buildscript {
   ext {
      springBootVersion = ‘3.3.3’
   }
   repositories {
      mavenCentral()
   }
   dependencies {
      classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
   }
}

apply plugin: ‘java’
apply plugin: ‘eclipse’
apply plugin: ‘org.springframework.boot’

group = ‘com.tutorialspoint’
version = ‘0.0.1-SNAPSHOT’
sourceCompatibility = 21

repositories {
   mavenCentral()
}

dependencies {
   compile(‘org.springframework.boot:spring-boot-starter-web’)
   compile group: ‘org.springframework.boot’, name: ‘spring-boot-starter-thymeleaf’
   testCompile(‘org.springframework.boot:spring-boot-starter-test’)
}

以下給出了控制器類檔案 – ViewController.java:

ViewController.java

package com.tutorialspoint.demo.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;

@Controller
public class ViewController {
   @GetMapping("/view-products")
   public String viewProducts() {
      return "view-products";
   }
   @GetMapping("/add-products")
   public String addProducts() {
      return "add-products";
   }
}

view-products.html檔案如下所示:

view-products.html

<!DOCTYPE html>
<html>
   <head>
      <meta charset = "ISO-8859-1"/>
      <title>View Products</title>
      <script src = "https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
      
      <script>
         $(document).ready(function(){
            $.getJSON("https://:8080/products", function(result){
               $.each(result, function(key,value) {
                  $("#productsJson").append(value.id+" "+value.name+" ");
               }); 
            });
         });
      </script>
   </head>
   
   <body>
      <div id = "productsJson"> </div>
   </body>
</html>

add-products.html檔案如下所示:

add-products.html

<!DOCTYPE html>
<html>
   <head>
      <meta charset = "ISO-8859-1" />
      <title>Add Products</title>
      <script src = "https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
      
      <script>
         $(document).ready(function() {
            $("button").click(function() {
               var productmodel = {
                  id : "3",
                  name : "Ginger"
               };
               var requestJSON = JSON.stringify(productmodel);
               $.ajax({
                  type : "POST",
                  url : "https://:8080/products",
                  headers : {
                     "Content-Type" : "application/json"
                  },
                  data : requestJSON,
                  success : function(data) {
                     alert(data);
                  },
                  error : function(data) {
                  }
               });
            });
         });
      </script>
   </head>
   
   <body>
      <button>Click here to submit the form</button>
   </body>
</html>

以下是主要的Spring Boot應用程式類檔案:

DemoApplication.java

package com.tutorialspoint.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {
   public static void main(String[] args) {
      SpringApplication.run(DemoApplication.class, args);
   }
}

現在,您可以建立一個可執行JAR檔案,並使用以下Maven或Gradle命令執行Spring Boot應用程式。

對於Maven,請使用以下命令:

mvn clean install

“BUILD SUCCESS”後,您可以在target目錄下找到JAR檔案。

對於Gradle,請使用以下命令:

gradle clean build

“BUILD SUCCESSFUL”後,您可以在build/libs目錄下找到JAR檔案。

使用以下命令執行JAR檔案:

java –jar <JARFILE> 

現在,應用程式已在Tomcat埠8080上啟動。

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/

[32m :: Spring Boot :: [39m              [2m (v3.3.3)[0;39m

[2024-09-06T16:21:33Z] [org.springframework.boot.StartupInfoLogger] [main] [50] [INFO ] Starting DemoApplication using Java 21.0.3 with PID 12540 (E:\Dev\demo\target\classes started by Tutorialspoint in E:\Dev\demo)
[2024-09-06T16:21:33Z] [org.springframework.boot.SpringApplication] [main] [654] [INFO ] No active profile set, falling back to 1 default profile: "default"
[2024-09-06T16:21:35Z] [org.springframework.boot.web.embedded.tomcat.TomcatWebServer] [main] [111] [INFO ] Tomcat initialized with port 8080 (http)
[2024-09-06T16:21:35Z] [org.apache.juli.logging.DirectJDKLog] [main] [173] [INFO ] Initializing ProtocolHandler ["http-nio-8080"]
[2024-09-06T16:21:35Z] [org.apache.juli.logging.DirectJDKLog] [main] [173] [INFO ] Starting service [Tomcat]
[2024-09-06T16:21:35Z] [org.apache.juli.logging.DirectJDKLog] [main] [173] [INFO ] Starting Servlet engine: [Apache Tomcat/10.1.28]
[2024-09-06T16:21:35Z] [org.apache.juli.logging.DirectJDKLog] [main] [173] [INFO ] Initializing Spring embedded WebApplicationContext
[2024-09-06T16:21:35Z] [org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext] [main] [296] [INFO ] Root WebApplicationContext: initialization completed in 1218 ms
[2024-09-06T16:21:35Z] [org.springframework.boot.autoconfigure.web.servlet.WelcomePageHandlerMapping] [main] [59] [INFO ] Adding welcome page template: index
[2024-09-06T16:21:35Z] [org.apache.juli.logging.DirectJDKLog] [main] [173] [INFO ] Starting ProtocolHandler ["http-nio-8080"]
[2024-09-06T16:21:35Z] [org.springframework.boot.web.embedded.tomcat.TomcatWebServer] [main] [243] [INFO ] Tomcat started on port 8080 (http) with context path '/'
[2024-09-06T16:21:35Z] [org.springframework.boot.StartupInfoLogger] [main] [56] [INFO ] Started DemoApplication in 2.155 seconds (process running for 3.448)

現在在您的Web瀏覽器中點選URL,您可以看到如下所示的輸出:

https://:8080/view-products

1Honey_2Almond

https://:8080/add-products

Submit Form Spring Boot

現在,單擊按鈕**點選此處提交表單**,您可以看到如下所示的結果:

Submit Form Spring Boot Output Window

現在,點選檢視產品URL,檢視已建立的產品。

https://:8080/view-products

1Honey 2Almond 3Ginger

Angular JS

要使用Angular JS使用API,您可以使用以下示例:

使用以下程式碼建立Angular JS控制器以使用GET API - **https://:8080/products**:

angular.module('demo', [])
.controller('Hello', function($scope, $http) {
   $http.get('https://:8080/products').
   then(function(response) {
      $scope.products = response.data;
   });
});

使用以下程式碼建立Angular JS控制器以使用POST API - **https://:8080/products**:

angular.module('demo', [])
.controller('Hello', function($scope, $http) {
   $http.post('https://:8080/products',data).
   then(function(response) {
      console.log("Product created successfully");
   });
});

**注意** - Post方法資料表示建立產品的JSON格式的請求正文。

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