SpringBoot官网例子（3）——Consuming a RESTful Web Service（消费一个RESTful的web服务）

1、准备工作

原文：https://spring.io/guides/gs/consuming-rest/

• ＞=1.8的JDK
• Eclipse（其它任何合适的IDE）
• Maven3.2（官网也有Gradle的构建

2、 POM文件

仍然是一个子模块，父工程的pom https://blog.youkuaiyun.com/csdn86868686888/article/details/103758256

<properties>
		<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>

3、工程

工程结构：

代码

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

@JsonIgnoreProperties(ignoreUnknown = true)
public class Value {

	    private Long id;
	    private String quote;

	    public Value() {
	    }

	    //省略了get和set方法

	    @Override
	    public String toString() {
	        return "Value{" +
	                "id=" + id +
	                ", quote='" + quote + '\'' +
	                '}';
	    }
}

package com.springboot.entity;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

@JsonIgnoreProperties(ignoreUnknown = true)
public class Quote {
	 private String type;
	    private Value value;

	    public Quote() {
	    }

	    //省略了get和set方法
	    @Override
	    public String toString() {
	        return "Quote{" +
	                "type='" + type + '\'' +
	                ", value=" + value +
	                '}';
	    }
}

package com.springboot;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.client.RestTemplateBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

import com.springboot.entity.Quote;

@SpringBootApplication
public class Application {
	
	private static final Logger log = LoggerFactory.getLogger(Application.class);
	
	public static void main(String[] args) {
		SpringApplication.run(Application.class, args);
	}
	
	@Bean
	public RestTemplate restTemplate(RestTemplateBuilder builder) {
		return builder.build();	}
	
	@Bean
	public CommandLineRunner run(RestTemplate restTemplate) {
		return args->{
			Quote quote=restTemplate.getForObject("https://gturnquist-quoters.cfapps.io/api/random", Quote.class);
			log.info(quote.toString());
		};
	}
}

4、总结

执行结果是这样的：

有一个服务，它的调用接口是https://gturnquist-quoters.cfapps.io/api/random

每一次调用，它会返回如下的数据格式：

{
   type: "success",
   value: {
      id: 10,
      quote: "Really loving Spring Boot, makes stand alone Spring apps easy."
   }
}

• @JsonIgnoreProperties(ignoreUnknown = true)，将这个注解写在类上之后，就会忽略类中不存在的字段。
• RestTemplate，使用Jackson JSON来处理传入的数据，将其转化为一个类。
• CommandLineRunner，启动时运行restTemplate

代码戳https://github.co/github20131983/springboot