本地启动Java程序报错Connection refused to host: 127.0.0.1

## 简介

> 重装系统后，使用Idea启动springboot项目时，出现的奇奇怪怪的报错。
> 
> 参考文章：[解决RMI的Connection refused to host: 127.0.0.1](https://www.cnblogs.com/qianxinggz/p/13277093.html)

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## 错误信息

```
java.rmi.ConnectException: Connection refused to host: 127.0.0.1; nested exception is: 
	java.net.ConnectException: Connection refused: connect
	at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:623)
	at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:216)
	at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:202)
	at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:342)
	at sun.rmi.registry.RegistryImpl_Stub.bind(RegistryImpl_Stub.java:65)
	at java.rmi.Naming.bind(Naming.java:128)
	at com.weblogictest.rmitest.ServerDemo.main(ServerDemo.java:16)
Caused by: java.net.ConnectException: Connection refused: connect
	at java.net.DualStackPlainSocketImpl.connect0(Native Method)
	at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
	at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
	at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
	at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
	at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
	at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
	at java.net.Socket.connect(Socket.java:606)
	at java.net.Socket.connect(Socket.java:555)
	at java.net.Socket.<init>(Socket.java:451)
	at java.net.Socket.<init>(Socket.java:228)
	at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:40)
	at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:148)
	at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:617)
	... 6 more
```

## 解决

我本地是防火墙的问题。。不知道是hosts文件哪里配置不对，关闭防火墙就好了。如果关闭没好，可以重启一次电脑试试。