java.net.ProtocolException: Invalid HTTP method: PATCH

先上代码
这是代码报错的配置

@Configuration
public class RestTemplateConfig {
    @Bean
    public ClientHttpRequestFactory simpleClientHttpRequestFactory(){
        SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();
        return factory;
    }
}

SimpleClientHttpRequestFactory 继承自 ClientHttpRequestFactory，同时继承ClientHttpRequestFactory的有

主要有4个，分别是

1. SimpleClientHttpRequestFactory
2. OkHttp3ClientHttpRequestFactory
3. HttpComponentsClientHttpRequestFactory
4. Netty4ClientHttpRequestFactory
   我们先看默认的SimpleClientHttpRequestFactory
   1、SimpleClientHttpRequestFactory

	@Override
	public ClientHttpRequest createRequest(URI uri, HttpMethod httpMethod) throws IOException {
		HttpURLConnection connection = openConnection(uri.toURL(), this.proxy);
		prepareConnection(connection, httpMethod.name());

		if (this.bufferRequestBody) {
			return new SimpleBufferingClientHttpRequest(connection, this.outputStreaming);
		}
		else {
			return new SimpleStreamingClientHttpRequest(connection, this.chunkSize, this.outputStreaming);
		}
	}

这里用到的是 HttpURLConnection，点进去看

可以看到支持的请求类型，根本就没有patch，说明这个HttpURLConnection是不支持patch请求，代码里边也有如下判断，就是非常简单粗暴循环这个支持的请求类型数组，不在这个数组中的请求一律抛出异常

也就是说默认的restTemplate是不支持patch请求的。
找到问题所在了，那应该怎么去解决问题呢。更换对应的工厂类，并添加对应的jar包就可以了
解决方案一：

    @Bean
    public ClientHttpRequestFactory simpleClientHttpRequestFactory() {
        OkHttp3ClientHttpRequestFactory factory = new OkHttp3ClientHttpRequestFactory();
        return factory;
    }

        
            com.squareup.okhttp3
            okhttp
        

解决方案二：

    @Bean
    public ClientHttpRequestFactory simpleClientHttpRequestFactory() {
        HttpComponentsClientHttpRequestFactory factory = new HttpComponentsClientHttpRequestFactory();
        return factory;
    }

        
            org.apache.httpcomponents
            httpclient