SpringBoot實戰(三)之使用RestFul Web服務

一、導入maven依賴

<?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>1.5.8.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>      

二、建構實體

Quote.java

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 +
                '}';
    }
}      

Value.java

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 + '\'' +
                '}';
    }
}      

@JsonIgnore注解用來忽略某些字段，可以用在Field或者Getter方法上，用在Setter方法時，和Filed效果一樣。這個注解隻能用在POJO存在的字段要忽略的情況，不能滿足現在需要的情況。

@JsonIgnoreProperties(ignoreUnknown = true)，将這個注解寫在類上之後，就會忽略類中不存在的字段，可以滿足目前的需要。這個注解還可以指定要忽略的字段。使用方法如下：

@JsonIgnoreProperties({ "internalId", "secretKey" })

指定的字段不會被序列化和反序列化。

三、編寫啟動類

package hello;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.springframework.web.client.RestTemplate;

public class Application {

    private static final Logger log = LoggerFactory.getLogger(Application.class);

    public static void main(String args[]) {
        RestTemplate restTemplate = new RestTemplate();
        Quote quote = restTemplate.getForObject("http://gturnquist-quoters.cfapps.io/api/random", Quote.class);
        log.info(quote.toString());
    }

}      

運作後控制台顯示結果為:

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());
        };
    }
}      

它

RestTemplateBuilder

是由Spring注入的，如果你使用它來建立一個，

RestTemplate

那麼你将受益于Spring Boot中帶有消息轉換器和請求工廠的所有自動配置。我們還将其提取

RestTemplate

為a 

@Bean

以使其更容易測試（可以通過這種方式更容易地進行模拟）。

最後執行mvn clean install或者mvn install，生成jar包，通過cmd指令執行java -jar  gs-consume-rest-0.1.0.jar

出現如紅色标記處，表示成功開發一個RestFul用戶端。