mysql和jsp连接问题，500错误

Question

jsp连接数据库制作一个商品网站，登录界面输入账号密码登录500错误，每一个连接数据库的界面都是500，求大佬解答，就是下面这个c'w
登录反馈结果
com.mysql.jdbc.CommunicationsException: Communications link failure due to underlying exception: ** BEGIN NESTED EXCEPTION ** java.net.UnknownHostException MESSAGE: local STACKTRACE: java.net.UnknownHostException: local at java.net.InetAddress.getAllByName0(InetAddress.java:1157) at java.net.InetAddress.getAllByName(InetAddress.java:1083) at java.net.InetAddress.getAllByName(InetAddress.java:1019) at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:246) at com.mysql.jdbc.MysqlIO.(MysqlIO.java:271) at com.mysql.jdbc.Connection.createNewIO(Connection.java:2771) at com.mysql.jdbc.Connection.(Connection.java:1555) at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:285) at java.sql.DriverManager.getConnection(DriverManager.java:582) at java.sql.DriverManager.getConnection(DriverManager.java:207) at myservlet.control.HandleLogin.doPost(HandleLogin.java:40) at javax.servlet.http.HttpServlet.service(HttpServlet.java:710) at javax.servlet.http.HttpServlet.service(HttpServlet.java:803) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:230) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:104) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:261) at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844) at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:581) at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447) at java.lang.Thread.run(Thread.java:619) ** END NESTED EXCEPTION ** Last packet sent to the server was 0 ms ago.

Answer 1

可能是主机名配置问题：
/etc/hosts中配置对应本机IP,否则java.net.InetAddress.getLocalHost会抛出java.Net.UnknownHostException异常。
查一下目标服务器的hosts文件。