Too many open files--CPU过高

问题现象：

服务器CPU过高，重启后两台服务器只能顶一个小时，CPU就过高，访问不了了

错误日志：

02-Mar-2020 10:46:17.749 SEVERE [http-nio-8080-Acceptor-0] org.apache.tomcat.util.net.NioEndpoint$Acceptor.run Socket accept failed
java.io.IOException: Too many open files
at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method)
at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:422)
at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:250)
at org.apache.tomcat.util.net.NioEndpoint$Acceptor.run(NioEndpoint.java:693)
at java.lang.Thread.run(Thread.java:745)

修改前代码：

static RestHighLevelClient client=null;
// 取得实例
public static synchronized RestHighLevelClient getClient() {
          
   
String address0 = PropertiesUtil.getValue("es_address0");
String address1 = PropertiesUtil.getValue("es_address1");
int port0 = Integer.valueOf(PropertiesUtil.getValue("es_port0"));
int port1 = Integer.valueOf(PropertiesUtil.getValue("es_port1"));
client = new RestHighLevelClient(
RestClient.builder(
new HttpHost(address0, port0, "http"),
new HttpHost(address1, port1, "http")));
return client;
}

错误原因：

client每次都创建连接，而且从不关闭

修改方案：

创建一个公用的client连接，每次查询时，先判断一下连接是否为空，如果为空，则新建一个，如果不为空，则公用之前的连接

修改后代码：

static RestHighLevelClient client=null;
// 取得实例
public static synchronized RestHighLevelClient getClient() {
          
   
if(client==null){
          
   
String address0 = PropertiesUtil.getValue("es_address0");
String address1 = PropertiesUtil.getValue("es_address1");
int port0 = Integer.valueOf(PropertiesUtil.getValue("es_port0"));
int port1 = Integer.valueOf(PropertiesUtil.getValue("es_port1"));
client = new RestHighLevelClient(
RestClient.builder(
new HttpHost(address0, port0, "http"),
new HttpHost(address1, port1, "http")));
}
return client;
}