Spring Boot Rest模板

Rest模板用於創建使用RESTful Web服務的應用程序。使用exchange()方法爲所有HTTP方法使用Web服務。 下面給出的代碼顯示瞭如何創建Rest模板Bean以自動連接Rest模板對象。

package com.yiibai.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

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

GET

通過使用RestTemplate類的exchange()方法來使用GET API,
假設此URL => http://localhost:8080/products返回以下JSON,將使用以下代碼使用Rest Template來使用此API響應 -

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

必須遵循給定的點來使用API -

  • 自動裝配Rest模板對象。
  • 使用HttpHeaders設置請求標頭。
  • 使用HttpEntity包裝請求對象。
  • Exchange()方法提供URL,HttpMethod和Return類型。
@RestController
public class ConsumeWebService {
   @Autowired
   RestTemplate restTemplate;

   @RequestMapping(value = "/template/products")
   public String getProductList() {
      HttpHeaders headers = new HttpHeaders();
      headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
      HttpEntity <String> entity = new HttpEntity<String>(headers);

      return restTemplate.exchange("
         http://localhost:8080/products", HttpMethod.GET, entity, String.class).getBody();
   }
}

POST

通過使用RestTemplateexchange()方法來使用POST API

假設此URL => http://localhost:8080/products返回如下所示的響應,使用Rest模板測試此API響應。

下面給出的代碼是請求正文 -

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

下面給出的代碼是響應內容 -

Product is created successfully

需要遵循以下給出的要點來使用API -

  • 自動裝配Rest模板對象。
  • 使用HttpHeaders設置請求標頭。
  • 使用HttpEntity包裝請求對象。 在這裏將Product對象包裝起來以將其發送到請求主體。

exchange()方法提供URL,HttpMethod和Return類型。

@RestController
public class ConsumeWebService {
   @Autowired
   RestTemplate restTemplate;

   @RequestMapping(value = "/template/products", method = RequestMethod.POST)
   public String createProducts(@RequestBody Product product) {
      HttpHeaders headers = new HttpHeaders();
      headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
      HttpEntity<Product> entity = new HttpEntity<Product>(product,headers);

      return restTemplate.exchange(
         "http://localhost:8080/products", HttpMethod.POST, entity, String.class).getBody();
   }
}

PUT

通過使用RestTemplateexchange()方法來使用PUT API。

假設此URL=> http://localhost:8080/products/3返回以下響應,使用RestTemplate來響應此API。

下面給出的代碼是請求主體 -

{
   "name":"Huawei"
}

下面給出的代碼是響應結果 -

Product is updated successfully

必須遵循以下給出的要點來使用API -

  • 自動裝配Rest模板對象。
  • 使用HttpHeaders設置請求標頭。
  • 使用HttpEntity包裝請求對象。 在這裏將Product對象包裝起來以將其發送到請求主體。

exchange()方法提供URLHttpMethodReturn類型。

@RestController
public class ConsumeWebService {
   @Autowired
   RestTemplate restTemplate;

   @RequestMapping(value = "/template/products/{id}", method = RequestMethod.PUT)
   public String updateProduct(@PathVariable("id") String id, @RequestBody Product product) {
      HttpHeaders headers = new HttpHeaders();
      headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
      HttpEntity<Product> entity = new HttpEntity<Product>(product,headers);

      return restTemplate.exchange(
         "http://localhost:8080/products/"+id, HttpMethod.PUT, entity, String.class).getBody();
   }
}

DELETE

通過使用RestTemplateexchange()方法來使用DELETE API

假設此URL => http://localhost:8080/products/3返回下面給出的響應,將使用RestTemplate來使用此API響應。

下面顯示的這行代碼是響應正文 -

Product is deleted successfully

必須按照下面顯示的點來使用API -

  • 自動裝配Rest模板對象。
  • 使用HttpHeaders設置請求標頭。
  • 使用HttpEntity包裝請求對象。

exchange()方法提供URL,HttpMethod和Return類型。

@RestController
public class ConsumeWebService {
   @Autowired
   RestTemplate restTemplate;

   @RequestMapping(value = "/template/products/{id}", method = RequestMethod.DELETE)
   public String deleteProduct(@PathVariable("id") String id) {
      HttpHeaders headers = new HttpHeaders();
      headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
      HttpEntity<Product> entity = new HttpEntity<Product>(headers);

      return restTemplate.exchange(
         "http://localhost:8080/products/"+id, HttpMethod.DELETE, entity, String.class).getBody();
   }
}

完整的Rest Template控制器類文件如下 -

package com.yiibai.demo.controller;

import java.util.Arrays;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.MediaType;

import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import com.yiibai.demo.model.Product;

@RestController
public class ConsumeWebService {
   @Autowired
   RestTemplate restTemplate;

   @RequestMapping(value = "/template/products")
   public String getProductList() {
      HttpHeaders headers = new HttpHeaders();
      headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
      HttpEntity<String> entity = new HttpEntity<String>(headers);

      return restTemplate.exchange(
         "http://localhost:8080/products", HttpMethod.GET, entity, String.class).getBody();
   }
   @RequestMapping(value = "/template/products", method = RequestMethod.POST)
   public String createProducts(@RequestBody Product product) {
      HttpHeaders headers = new HttpHeaders();
      headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
      HttpEntity<Product> entity = new HttpEntity<Product>(product,headers);

      return restTemplate.exchange(
         "http://localhost:8080/products", HttpMethod.POST, entity, String.class).getBody();
   }
   @RequestMapping(value = "/template/products/{id}", method = RequestMethod.PUT)
   public String updateProduct(@PathVariable("id") String id, @RequestBody Product product) {
      HttpHeaders headers = new HttpHeaders();
      headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
      HttpEntity<Product> entity = new HttpEntity<Product>(product,headers);

      return restTemplate.exchange(
         "http://localhost:8080/products/"+id, HttpMethod.PUT, entity, String.class).getBody();
   }
   @RequestMapping(value = "/template/products/{id}", method = RequestMethod.DELETE)
   public String deleteProduct(@PathVariable("id") String id) {
      HttpHeaders headers = new HttpHeaders();
      headers.setAccept(Arrays.asList(MediaType.APPLICATION_JSON));
      HttpEntity<Product> entity = new HttpEntity<Product>(headers);

      return restTemplate.exchange(
         "http://localhost:8080/products/"+id, HttpMethod.DELETE, entity, String.class).getBody();
   }
}

Spring Boot應用程序類 - DemoApplication.java 的代碼如下 -

package com.yiibai.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);
   }
}

Maven構建文件- pom.xml 的代碼如下 -

<?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 
   http://maven.apache.org/xsd/maven-4.0.0.xsd">

   <modelVersion>4.0.0</modelVersion>
   <groupId>com.yiibai</groupId>
   <artifactId>demo</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <packaging>jar</packaging>
   <name>demo</name>
   <description>Demo project for Spring Boot</description>

   <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>1.5.8.RELEASE</version>
      <relativePath/> 
   </parent>

   <properties>
      <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
      <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
      <java.version>1.8</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>
   </dependencies>

   <build>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
         </plugin>
      </plugins>
   </build>

</project>

Gradle構建文件 - build.gradle 的代碼如下 -

buildscript {
   ext {
      springBootVersion = '1.5.8.RELEASE'
   }
   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.yiibai'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8

repositories {
   mavenCentral()
}
dependencies {
   compile('org.springframework.boot:spring-boot-starter-web')
   testCompile('org.springframework.boot:spring-boot-starter-test')
}

創建可執行的JAR文件,並使用以下Maven或Gradle命令運行Spring Boot應用程序:

對於Maven,使用下面給出的命令 -

mvn clean install

在「BUILD SUCCESS」之後,可以在target目錄下找到JAR文件。

對於Gradle,使用下面顯示的命令 -

gradle clean build

在「BUILD SUCCESSFUL」之後,可以在build/libs 目錄下找到JAR文件。

現在,使用以下命令運行JAR文件 -

java –jar <JARFILE>

現在,應用程序已在Tomcat端口8080上啓動。

現在點擊POSTMAN 應用程序中的以下URL,可以看到輸出。
通過Rest模板獲取產品 - http://localhost:8080/template/products

Spring Boot Rest模板

創建產品POST - http://localhost:8080/template/products

Spring Boot Rest模板

更新產品PUT - http://localhost:8080/template/products/3

Spring Boot Rest模板

刪除產品 DELETE - http://localhost:8080/template/products/3

Spring Boot Rest模板