使用RestTemplate发送GET请求，并且支持传递Requ

问题

今天在使用RestTemplate请求es的接口时，传递的json参数没有起到作用。后面发现默认的RestTemplate是不支持通过Body携带参数

原因

RestTemplate支持通过setRequestFactory设置HTTP请求客户端工具，支持jdk、httpclient、okHttp等，默认使用的是SimpleClientHttpRequestFactory，该工程使用的JDK实现，底层使用OutputStream来传递body数据，不支持GET传递body。

解决

1、
在pom.xml中添加依赖包,version在4.3.4及以上就可以

        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>{your version}</version>
        </dependency>

2、扩展HttpComponentsClientHttpRequestFactory

package com.tencent.goff.configuration;

import org.apache.http.client.methods.HttpEntityEnclosingRequestBase;
import org.apache.http.client.methods.HttpUriRequest;
import org.springframework.http.HttpMethod;
import org.springframework.http.client.HttpComponentsClientHttpRequestFactory;

import java.net.URI;

public class HttpComponentsClientRestfulHttpRequestFactory extends HttpComponentsClientHttpRequestFactory {
    @Override
    protected HttpUriRequest createHttpUriRequest(HttpMethod httpMethod, URI uri) {

        if (httpMethod == HttpMethod.GET) {
            return new HttpGetRequestWithEntity(uri);
        }
        return super.createHttpUriRequest(httpMethod, uri);
    }

    /**
     * 定义HttpGetRequestWithEntity实现HttpEntityEnclosingRequestBase抽象类，以支持GET请求携带body数据
     */

    private static final class HttpGetRequestWithEntity extends HttpEntityEnclosingRequestBase {
        public HttpGetRequestWithEntity(final URI uri) {
            super.setURI(uri);
        }

        @Override
        public String getMethod() {
            return HttpMethod.GET.name();

        }
    }
}

3、在定义RestTemplate时，使用自定义factory

@Configuration
public class RestTemplateConfig {
    @Bean
    public RestTemplate restTemplate() {

        RestTemplate restTemplate = new RestTemplate(getClientHttpRequestFactory());
        restTemplate.setRequestFactory(new HttpComponentsClientRestfulHttpRequestFactory());
        return restTemplate;
    }

    // 设置超时时间
    private SimpleClientHttpRequestFactory getClientHttpRequestFactory() {
        SimpleClientHttpRequestFactory clientHttpRequestFactory = new SimpleClientHttpRequestFactory();
        // Connect timeout 3s
        clientHttpRequestFactory.setConnectTimeout(60000);
        // Read timeout 3s
        clientHttpRequestFactory.setReadTimeout(60000);
        return clientHttpRequestFactory;
    }
}

通过上面步骤解决了get请求不能穿body的问题
参考https://www.it610.com/article/1290441629521485824.htm