HttpClient高并发下性能优化

1、CloseableHttpClient的使用和优化（案例1）

https://blog.youkuaiyun.com/u010285974/article/details/85696239

2、HttpClient连接池设置引发的一次雪崩（案例2）

https://blog.youkuaiyun.com/u010889990/article/details/96236617

3、使用httpClient连接池处理get或post请求

https://m.wang1314.com/doc/webapp/topic/20923280.html

创建一个HttpClient

public class HttpClientUtil{
	
    private static RequestConfig requestConfig = null;
	//httpClient
	private static final CloseableHttpClient httpClient;
	
	private static final PoolingHttpClientConnectionManager cm;
	//httpGet方法
//	private static final HttpGet httpget;
	//httpPost方法
//	private static final HttpPost httpPost;
    //响应处理器
//	private static final ResponseHandler<String> responseHandler;
  	static{
        //初始化HTTP请求配置，设置连接池请求、获取数据和建立连接超时时间
        requestConfig = RequestConfig.custom()
			        				 .setConnectionRequestTimeout(40000)
			        				 .setSocketTimeout(40000)
			        				 .setConnectTimeout(40000)
			        				 .build();
        
//        System.setProperty("http.maxConnections","50");//最大活跃连接数
//        System.setProperty("http.keepAlive", "true");//长连接
        
        //连接池配置
        cm = new PoolingHttpClientConnectionManager();
        cm.setMaxTotal(500);//最大连接数
        cm.setDefaultMaxPerRoute(100);//每个路由最大连接数
        //创建定制http客户端
        httpClient = HttpClients.custom()
        						.setConnectionManager(cm)
				                .setRetryHandler(new DefaultHttpRequestRetryHandler(0,false))//设置http client的重试次数，默认是3次；当前是禁用掉（如果项目量不到，这个默认即可）
				                .build();
        //初始化response解析器
//        responseHandler = new BasicResponseHandler();
    }

连接池配置连接数

1、方法一

PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();

cm.setMaxTotal(500);//最大连接数
cm.setDefaultMaxPerRoute(100);//每个路由最大连接数

httpClient = HttpClients.custom().setConnectionManager(cm).build();

2、方法二

System.setProperty("http.maxConnections","50");//最大活跃连接数
 httpClient = HttpClients.custom().useSystemProperties().build();

3、方法三

 HttpClientBuilder builder = HttpClientBuilder.create();
 builder.setMaxConnTotal(500).setMaxConnPerRoute(100);
 HttpClient httpClient = builder.build();