Rest Template

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2023-12-01

Rest模板用于创建使用RESTful Web服务的应用程序。您可以使用exchange()方法为所有HTTP方法使用Web服务。下面给出的代码显示了如何创建Bean for Rest Template以自动连接Rest Template对象。

package cn.xnip.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

Consuming the GET API by using RestTemplate - exchange() method

假设此URL http://localhost:8080/products返回以下JSON，我们将使用以下代码使用Rest Template来使用此API响应 -

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

您将必须遵循给定的点来使用API -

自动装配Rest模板对象。
使用HttpHeaders设置请求标头。
使用HttpEntity包装请求对象。
为Exchange（）方法提供URL，HttpMethod和Return类型。

@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

Consuming POST API by using RestTemplate - exchange() method

假设此URL http://localhost:8080/products返回如下所示的响应，我们将使用Rest模板使用此API响应。

下面给出的代码是请求正文 -

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

下面给出的代码是响应机构 -

Product is created successfully

您必须遵循以下给出的要点来使用API -

自动装配Rest模板对象。
使用HttpHeaders设置请求标头。
使用HttpEntity包装请求对象。在这里，我们将Product对象包装起来以将其发送到请求主体。
为exchange（）方法提供URL，HttpMethod和Return类型。

@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

Consuming PUT API by using RestTemplate - exchange() method

假设此URL http://localhost:8080/products/3返回以下响应，我们将使用Rest Template来使用此API响应。

下面给出的代码是申请机构 -

{
   "name":"Indian Ginger"
}

下面给出的代码是响应机构 -

Product is updated successfully

您必须遵循以下给出的要点来使用API -

自动装配Rest模板对象。
使用HttpHeaders设置请求标头。
使用HttpEntity包装请求对象。在这里，我们将Product对象包装起来以将其发送到请求主体。
为exchange（）方法提供URL，HttpMethod和Return类型。

@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

Consuming DELETE API by using RestTemplate - exchange() method

假设此URL http://localhost:8080/products/3返回下面给出的响应，我们将使用Rest Template来使用此API响应。

下面显示的这行代码是响应正文 -

Product is deleted successfully

您必须按照下面显示的点来使用API -

自动装配Rest模板对象。
使用HttpHeaders设置请求标头。
使用HttpEntity包装请求对象。
为exchange（）方法提供URL，HttpMethod和Return类型。

@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 Controller类文件如下 -

package cn.xnip.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 cn.xnip.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 Application Class的代码 - DemoApplication.java如下 -

package cn.xnip.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 build - pom.xml的代码如下 -

<?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>cn.xnip</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 Build - build.gradle的代码如下 -

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 = 'cn.xnip'
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')
}

您可以创建可执行的JAR文件，并使用以下Maven或Gradle命令运行Spring Boot应用程序 -

对于Maven，您可以使用下面给出的命令 -