解决异常：“The last packet sent successfully to the server was 0 milliseconds ago. ”的办法

  1 警告: com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@21ee9275 -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 
  2 com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
  3 
  4 The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
  5     at sun.reflect.GeneratedConstructorAccessor23.newInstance(Unknown Source)
  6     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
  7     at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
  8     at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
  9     at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:990)
 10     at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:342)
 11     at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2197)
 12     at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2230)
 13     at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2025)
 14     at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:778)
 15     at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
 16     at sun.reflect.GeneratedConstructorAccessor15.newInstance(Unknown Source)
 17     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
 18     at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
 19     at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
 20     at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:386)
 21     at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330)
 22     at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175)
 23     at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220)
 24     at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206)
 25     at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203)
 26     at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
 27     at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
 28     at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
 29     at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
 30     at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)
 31 Caused by: java.net.ConnectException: Connection refused: connect
 32     at java.net.DualStackPlainSocketImpl.connect0(Native Method)
 33     at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
 34     at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
 35     at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
 36     at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
 37     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
 38     at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
 39     at java.net.Socket.connect(Socket.java:589)
 40     at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:211)
 41     at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:301)
 42     ... 20 more
 43 
 44 八月 21, 2020 5:01:26 下午 com.mchange.v2.resourcepool.BasicResourcePool 
 45 警告: Having failed to acquire a resource, com.mchange.v2.resourcepool.BasicResourcePool@520d0d4e is interrupting all Threads waiting on a resource to check out. Will try again in response to new client requests.
 46 八月 21, 2020 5:01:26 下午 com.mchange.v2.resourcepool.BasicResourcePool 
 47 警告: com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@634f6fcf -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 
 48 com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
 49 
 50 The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
 51     at sun.reflect.GeneratedConstructorAccessor23.newInstance(Unknown Source)
 52     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
 53     at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
 54     at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
 55     at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:990)
 56     at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:342)
 57     at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2197)
 58     at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2230)
 59     at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2025)
 60     at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:778)
 61     at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
 62     at sun.reflect.GeneratedConstructorAccessor15.newInstance(Unknown Source)
 63     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
 64     at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
 65     at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
 66     at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:386)
 67     at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330)
 68     at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175)
 69     at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220)
 70     at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206)
 71     at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203)
 72     at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
 73     at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
 74     at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
 75     at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
 76     at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)
 77 Caused by: java.net.ConnectException: Connection refused: connect
 78     at java.net.DualStackPlainSocketImpl.connect0(Native Method)
 79     at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
 80     at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
 81     at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
 82     at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
 83     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
 84     at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
 85     at java.net.Socket.connect(Socket.java:589)
 86     at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:211)
 87     at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:301)
 88     ... 20 more
 89 
 90 八月 21, 2020 5:01:26 下午 com.mchange.v2.resourcepool.BasicResourcePool 
 91 警告: com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@6c971fde -- Acquisition Attempt Failed!!! Clearing pending acquires. While trying to acquire a needed new resource, we failed to succeed more than the maximum number of allowed acquisition attempts (30). Last acquisition attempt exception: 
 92 com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
 93 
 94 The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
 95     at sun.reflect.GeneratedConstructorAccessor23.newInstance(Unknown Source)
 96     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
 97     at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
 98     at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
 99     at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:990)
100     at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:342)
101     at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2197)
102     at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2230)
103     at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2025)
104     at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:778)
105     at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
106     at sun.reflect.GeneratedConstructorAccessor15.newInstance(Unknown Source)
107     at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
108     at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
109     at com.mysql.jdbc.Util.handleNewInstance(Util.java:425)
110     at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:386)
111     at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330)
112     at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:175)
113     at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:220)
114     at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:206)
115     at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:203)
116     at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1138)
117     at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1125)
118     at com.mchange.v2.resourcepool.BasicResourcePool.access$700(BasicResourcePool.java:44)
119     at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1870)
120     at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:696)
121 Caused by: java.net.ConnectException: Connection refused: connect
122     at java.net.DualStackPlainSocketImpl.connect0(Native Method)
123     at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:79)
124     at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
125     at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
126     at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
127     at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
128     at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
129     at java.net.Socket.connect(Socket.java:589)
130     at com.mysql.jdbc.StandardSocketFactory.connect(StandardSocketFactory.java:211)
131     at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:301)
132     ... 20 more