Telnet：连接到地址127.0.0.1：MacOS上拒绝连接

Question

我试图从java应用程序连接到我的数据库，但它拒绝连接，给出的错误是这个。

com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:400)
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1038)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:339)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2247)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2280)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2079)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:794)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:400)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:399)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:325)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at MainTest.main(MainTest.java:23)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:497)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)
Caused by: java.net.ConnectException: Connection refused
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:345)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:589)
    at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:214)
    at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:298)
    ... 20 more

搜索我发现问题不是代码，而是连接到我的本地主机，因为我可以连接到localhost如果我去我的网络浏览器，只是去'localhost'，我不能做一个telnet到localhost或127.0.0.1，它拒绝连接。

MacBook-Pro:etc alejandro-trabajo$ telnet localhost
Trying ::1...
telnet: connect to address ::1: Connection refused
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused
Trying fe80::1...
telnet: connect to address fe80::1: Connection refused
telnet: Unable to connect to remote host

我已经尝试了在web上找到的所有东西，创建了一个新的“hosts”文件，刷新了dns，重新启动了apache服务器，取消了httpd中“ServerName localhost”的注释。配置文件。。。我真的不知道该怎么办。

PS：ping到localhost完美工作

MacBook-Pro:etc alejandro-trabajo$ ping localhost
PING localhost (127.0.0.1): 56 data bytes
64 bytes from 127.0.0.1: icmp_seq=0 ttl=64 time=0.048 ms
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.075 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.126 ms
64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.121 ms
^C
--- localhost ping statistics ---
4 packets transmitted, 4 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.048/0.092/0.126/0.032 ms

Answer 1

也许这会有帮助。

~ $ ifconfig    
...
en0: flags=8863<UP,BROADCAST,SMART,RUNNING,SIMPLEX,MULTICAST> mtu 1500
    ether 8c:85:90:94:fb:70 
    inet6 fe80::14aa:f1f1:ede3:b942%en0 prefixlen 64 secured scopeid 0x8 
    inet 192.168.1.100


~ $ telnet localhost 1234    
    Trying ::1...`enter code here`
    telnet: connect to address ::1: Connection refused
    Trying 127.0.0.1...
    telnet: connect to address 127.0.0.1: Connection refused
    telnet: Unable to connect to remote host
~ $ telnet 127.0.0.1 1234
    Trying 127.0.0.1...
    telnet: connect to address 127.0.0.1: Connection refused
    telnet: Unable to connect to remote host
~ $ telnet 192.168.1.100 1234
    Trying 192.168.1.100...
    Connected to 192.168.1.100.
    Escape character is '^]'.
    This is a simple server