这个Demo是用来演示使用Restful Web Service的。官网参考文献
一、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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.springframework</groupId>
<artifactId>gs-consuming-rest</artifactId>
<version>0.1.0</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.5.RELEASE</version>
</parent>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
</dependency>
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
使用Spring Boot Maven plugin是为了利用它的自动寻找Main方法和可以将应用所依赖的所有包打包为一个可以运行的jar。
二、创建一些类来存储获取的数据
访问链接 http://gturnquist-quoters.cfapps.io/api/random,将获得随机数据
{"type":"success","value":{"id":11,"quote":"I have two hours today to build an app from scratch. @springboot to the rescue!"}}
我们用两个类来承接这个数据
package hello;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
@JsonIgnoreProperties(ignoreUnknown = true)
public class Quote {
private String type;
private Value value;
public Quote() {
}
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public Value getValue() {
return value;
}
public void setValue(Value value) {
this.value = value;
}
@Override
public String toString() {
return "Quote{" +
"type='" + type + '\'' +
", value=" + value +
'}';
}
}
package hello;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
@JsonIgnoreProperties(ignoreUnknown = true)
public class Value {
private Long id;
private String quote;
public Value() {
}
public Long getId() {
return this.id;
}
public String getQuote() {
return this.quote;
}
public void setId(Long id) {
this.id = id;
}
public void setQuote(String quote) {
this.quote = quote;
}
@Override
public String toString() {
return "Value{" +
"id=" + id +
", quote='" + quote + '\'' +
'}';
}
}
其中JsonIgnoreProperties的作用是,当获取的json数据的属性名与我们类的属性名不匹配时 忽视 它。
三、启动
启动获取数据我们通过普通的main方法就行了。但是我们也可以让springboot来管理应用的生命周期。好处是可以让springboot将json转换为相应的对象。
package hello;
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;
@SpringBootApplication
public class Application {
private static final Logger log = LoggerFactory.getLogger(Application.class);
public static void main(String args[]) {
SpringApplication.run(Application.class);
}
@Bean
public RestTemplate restTemplate(RestTemplateBuilder builder) {
return builder.build();
}
@Bean
public CommandLineRunner run(RestTemplate restTemplate) throws Exception {
return args -> {
Quote quote = restTemplate.getForObject(
"http://gturnquist-quoters.cfapps.io/api/random", Quote.class);
log.info(quote.toString());
};
}
}
将RestTemplate移到CommandLineRunner去是为了让json的解析发生在spirngboot启动项目之前运行。RestTemplateBuilder是被springboot自动注入的,如果使用RestTemplateBuilder产生RestTemplate,将得到springboot自动配置的好处(比如将json转换)。