之前在用zuul網(wǎng)關(guān)的時候，請求幾次然后連接就斷開了。原因是因?yàn)閔ttp1.1之后，默認(rèn)走的都是connection=keep-alive 長連接。但沒有心跳維持，顧1分鐘斷開一次。但RestFul一般都是走短連接就行了。因此想著只要修改頭部connection屬性就行了.

就是在過濾器中修改Zuul的RequestContext ctx對象

        //設(shè)置請求為短連接
        ctx.addZuulRequestHeader("connection", "close");

再次請求之后發(fā)現(xiàn)

?納尼，怎么還是長連接。那么說明可能是我的設(shè)置沒有生效或者被覆蓋掉了。遇到問題，除了度娘，跟著源碼走一遭也是最好的方式。花了大半天時間，終于讓我找到原因了。

原因是代理類ProxyRequestHelper里面有段邏輯。

public boolean isIncludedHeader(String headerName) {
		String name = headerName.toLowerCase();
		RequestContext ctx = RequestContext.getCurrentContext();
		if (ctx.containsKey(IGNORED_HEADERS)) {
			Object object = ctx.get(IGNORED_HEADERS);
			if (object instanceof Collection && ((Collection<?>) object).contains(name)) {
				return false;
			}
		}
		switch (name) {
		case "host":
			if(addHostHeader) {
				return true;
			}
		case "connection":
		case "content-length":
		case "server":
		case "transfer-encoding":
		case "x-application-context":
			return false;
		default:
			return true;
		}
	}

如果頭部存在"connection": "content-length": "server": "transfer-encoding": "x-application-context"這些頭的話都被跳過。不會被設(shè)置成功。應(yīng)該是zuul自己的一個機(jī)制把。

二、解決方式

那么問題找到了，該怎么修改呢？那么只能自定義路由了。繼承并重寫這個類。

1、實(shí)現(xiàn)自定義路由配置CustomZuulConfig

@Component
public class CustomZuulConfig {

    @Autowired
    ZuulProperties zuulProperties;

    @Value("${servletPath}")
    private String servletPath;

    @Bean
    public CustomRouteLocator routeLocator() {
        CustomRouteLocator routeLocator = new CustomRouteLocator(servletPath, this.zuulProperties);
        return routeLocator;
    }

}

2、實(shí)現(xiàn)自定義請求代理工具類重寫isIncludedHeader方法。

public class CustomRequestHelper extends ProxyRequestHelper {
    @Override
    public boolean isIncludedHeader(String headerName) {
        String name = headerName.toLowerCase();
        RequestContext ctx = RequestContext.getCurrentContext();
        if (ctx.containsKey(IGNORED_HEADERS)) {
            Object object = ctx.get(IGNORED_HEADERS);
            if (object instanceof Collection && ((Collection<?>)object).contains(name)) {
                return false;
            }
        }
        switch (name) {
            case "content-length":
            case "host":
            case "server":
            case "transfer-encoding":
            case "x-application-context":
                return false;
            default:
                return true;
        }
    }
}

3、重寫實(shí)現(xiàn)代理配置類

@Configuration
@EnableZuulProxy
public class CustomZuulProxyConfig extends ZuulProxyAutoConfiguration {

    @Bean
    @Override
    public SimpleHostRoutingFilter simpleHostRoutingFilter(ProxyRequestHelper helper, ZuulProperties zuulProperties,
            ApacheHttpClientConnectionManagerFactory connectionManagerFactory,
            ApacheHttpClientFactory httpClientFactory) {
        CustomRequestHelper customRequestHelper = new CustomRequestHelper();
        return new SimpleHostRoutingFilter(customRequestHelper, zuulProperties, connectionManagerFactory,
                httpClientFactory);
    }

}

然后重新啟動，查看請求頭。