Tag Archives: idea

There is no error when compiling and packaging the IDEA code, but the code displays an error

Uploading… Re-upload cancel

The figure is casually found on the Internet. It shows that the code is compiled successfully, but the packaging fails. When maven reimprot and mavn clean and idea invalidate cache are useless, it is recommended to empty the. Idea and. IML files in the workspace folder
the reason is incomplete or incorrect package guide information, which is caused by the disordered configuration information of the workspace of the idea itself.

 . iml Folder

Idea means module configuration information. Information of module
IML is the project configuration file of IntelliJ idea, which contains some configuration information of the current project Idea stores the configuration information of the project, including history, version control information, etc.

 .idea Folder

Idea stores the configuration information of the project, including history, version control information, etc.

Idea starts Tomcat console with garbled code but no error

Problem display

resolvent

1. Find the Tomcat installation directory  

  2. Open the logging.properties file from the conf folder
find the line java.util.logging.consolehandler.encoding = UTF-8 and change it to java.util.logging.consolehandler.encoding = GBK
that is, change the console code from UTF-8 to GBK

  Successful solution, give a praise

NoClassDefFoundError: io/ebean/bean/ EntityBean [How to Solve]

Error stack frame, as follows:

java.lang.NoClassDefFoundError: io/ebean/bean/EntityBean

	at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:468)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:74)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:369)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:363)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:362)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	at java.lang.Class.forName0(Native Method)
	at java.lang.Class.forName(Class.java:348)
	at sun.reflect.generics.factory.CoreReflectionFactory.makeNamedType(CoreReflectionFactory.java:114)
	at sun.reflect.generics.visitor.Reifier.visitClassTypeSignature(Reifier.java:125)
	at sun.reflect.generics.tree.ClassTypeSignature.accept(ClassTypeSignature.java:49)
	at sun.reflect.generics.visitor.Reifier.reifyTypeArguments(Reifier.java:68)
	at sun.reflect.generics.visitor.Reifier.visitClassTypeSignature(Reifier.java:138)
	at sun.reflect.generics.tree.ClassTypeSignature.accept(ClassTypeSignature.java:49)
	at sun.reflect.generics.repository.ClassRepository.getSuperInterfaces(ClassRepository.java:108)
	at java.lang.Class.getGenericInterfaces(Class.java:913)
	at org.springframework.core.ResolvableType.getInterfaces(ResolvableType.java:471)
	at org.springframework.core.GenericTypeResolver.buildTypeVariableMap(GenericTypeResolver.java:265)
	at org.springframework.core.GenericTypeResolver.getTypeVariableMap(GenericTypeResolver.java:242)
	at org.springframework.data.util.ClassTypeInformation.getTypeVariableMap(ClassTypeInformation.java:114)
	at org.springframework.data.util.ClassTypeInformation.getTypeVariableMap(ClassTypeInformation.java:103)
	at org.springframework.data.util.ClassTypeInformation.<init>(ClassTypeInformation.java:92)
	at org.springframework.data.util.ClassTypeInformation.lambda$from$1(ClassTypeInformation.java:70)
	at java.util.concurrent.ConcurrentMap.computeIfAbsent(ConcurrentMap.java:324)
	at org.springframework.data.util.ClassTypeInformation.from(ClassTypeInformation.java:70)
	at org.springframework.data.repository.core.support.AbstractRepositoryMetadata.<init>(AbstractRepositoryMetadata.java:58)
	at org.springframework.data.repository.core.support.DefaultRepositoryMetadata.<init>(DefaultRepositoryMetadata.java:52)
	at org.springframework.data.repository.core.support.AbstractRepositoryMetadata.getMetadata(AbstractRepositoryMetadata.java:73)
	at org.springframework.data.repository.config.RepositoryConfigurationExtensionSupport.getRepositoryConfigurations(RepositoryConfigurationExtensionSupport.java:98)
	at org.springframework.data.repository.config.RepositoryConfigurationDelegate.registerRepositoriesIn(RepositoryConfigurationDelegate.java:121)
	at org.springframework.boot.autoconfigure.data.AbstractRepositoryConfigurationSourceSupport.registerBeanDefinitions(AbstractRepositoryConfigurationSourceSupport.java:60)
	at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.lambda$loadBeanDefinitionsFromRegistrars$1(ConfigurationClassBeanDefinitionReader.java:358)
	at java.util.LinkedHashMap.forEach(LinkedHashMap.java:684)
	at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsFromRegistrars(ConfigurationClassBeanDefinitionReader.java:357)
	at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:145)
	at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitions(ConfigurationClassBeanDefinitionReader.java:117)
	at org.springframework.context.annotation.ConfigurationClassPostProcessor.processConfigBeanDefinitions(ConfigurationClassPostProcessor.java:328)
	at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanDefinitionRegistry(ConfigurationClassPostProcessor.java:233)
	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanDefinitionRegistryPostProcessors(PostProcessorRegistrationDelegate.java:273)
	at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:93)
	at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:694)
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:532)
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759)
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395)
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:327)
	at org.springframework.boot.test.context.SpringBootContextLoader.loadContext(SpringBootContextLoader.java:139)
	at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:99)
	at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:117)
	at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:108)
	at org.springframework.test.context.web.ServletTestExecutionListener.setUpRequestContextIfNecessary(ServletTestExecutionListener.java:190)
	at org.springframework.test.context.web.ServletTestExecutionListener.prepareTestInstance(ServletTestExecutionListener.java:132)
	at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:246)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:227)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:246)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:97)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
	at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
	at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
	at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:190)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:137)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:221)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)
Caused by: java.lang.ClassNotFoundException: io.ebean.bean.EntityBean
	at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
	... 78 more



The solution is to replace the idea entitybean enhancement plug-in. My computer is replaced with entitybean 10. X enhancement

Mac idea springboot project reported an error

Class JavaLaunchHelper is implemented in both /Library/Java/JavaVirtualMachines/jdk1.8.0_ 144.jdk/Contents/Home/bin/java (0x10dd324c0) and /Library/Java/JavaVirtualMachines/jdk1.8.0_ 144.jdk/contents/home/jre/lib/libinstrument.dylib error

To solve the problem, you need to set the idea custom properties. Click Help on the navigation bar and select Edit custom properties,

For the first time, there is no properties file. At this time, the following interface will pop up in idea to prompt you to create it. Click Create directly.

Write idea. No. launcher = true in idea.properties, and then restart idea.

When idea executes the command, an error is reported: CreateProcess error = 2. The system cannot find the specified file

Problem description

Error running ' mvn install:install-file -DgroupId=xxx.xxx.xxx -DartifactId=myArtifactId -Dversion=0.7.0 -Dpackaging=jar -Dfile=E:\myProject.jar ': Cannot run program "mvn" (in directory "E:\javawarkspace\webhisprotal\ips-portal-admin\hsa-ips-admin-biz\src\main\java\cn\hsa\ips\admin"): CreateProcess error=2, The system cannot find the specified file . However, it can be executed normally in the command line window.

Problem solving

When using the idea command, the prefix cannot have extra spaces. Note the beginning of the command: 'MVN install: install file... , there is a space here. Cause program exception.

SpringCloud: Error creating bean with name ‘configurationPropertiesBeans‘

[problem phenomenon]

When the springcloud system is built in the idea, a red error is prompted at runtime:


org.springframework.beans.factory.BeanCreationException: 
Error creating bean with name 'configurationPropertiesBeans' defined in class path resource 
[org/springframework/cloud/autoconfigure/ConfigurationPropertiesRebinderAutoConfiguration.class]: 
Post-processing of merged bean definition failed; nested exception is java.lang.IllegalStateException: 
Failed to introspect Class 
[org.springframework.cloud.context.properties.ConfigurationPropertiesBeans] 
from ClassLoader [[email protected]]

......

Caused by: java.lang.IllegalStateException: 
Failed to introspect Class 
[org.springframework.cloud.context.properties.ConfigurationPropertiesBeans] 
from ClassLoader [[email protected]]

......

Caused by: java.lang.NoClassDefFoundError: 
org/springframework/boot/context/properties/ConfigurationBeanFactoryMetadata

......

Caused by: java.lang.ClassNotFoundException: 
org.springframework.boot.context.properties.ConfigurationBeanFactoryMetadata

[reason]

This is a very common problem in the spring cloud system because the spring boot version is incompatible with the spring cloud version.

[solution]

The spring boot version and spring cloud version should be matched in strict accordance with the official version. Link to the official website:
https://spring.io/projects/spring-cloud

Different clouds need different boot versions, as shown in the figure:

Example of version change:

after version replacement, reload all Maven items, as shown in the figure:

If an error is still reported, re-execute the MVN clean package

IDEA maven Config MYSQL Connection Error: Could not create connection to database server.

Error message

2021.2\lib\idea_rt.jar;E:\IDEA\IDEA\IntelliJ IDEA 2021.2\plugins\junit\lib\junit5-rt.jar;E:\IDEA\IDEA\IntelliJ IDEA 2021.2\plugins\junit\lib\junit-rt.jar;E:\JDK1.8.301\jre\lib\charsets.jar;E:\JDK1.8.301\jre\lib\deploy.jar;E:\JDK1.8.301\jre\lib\ext\access-bridge-64.jar;E:\JDK1.8.301\jre\lib\ext\cldrdata.jar;E:\JDK1.8.301\jre\lib\ext\dnsns.jar;E:\JDK1.8.301\jre\lib\ext\jaccess.jar;E:\JDK1.8.301\jre\lib\ext\jfxrt.jar;E:\JDK1.8.301\jre\lib\ext\localedata.jar;E:\JDK1.8.301\jre\lib\ext\nashorn.jar;E:\JDK1.8.301\jre\lib\ext\sunec.jar;E:\JDK1.8.301\jre\lib\ext\sunjce_provider.jar;E:\JDK1.8.301\jre\lib\ext\sunmscapi.jar;E:\JDK1.8.301\jre\lib\ext\sunpkcs11.jar;E:\JDK1.8.301\jre\lib\ext\zipfs.jar;E:\JDK1.8.301\jre\lib\javaws.jar;E:\JDK1.8.301\jre\lib\jce.jar;E:\JDK1.8.301\jre\lib\jfr.jar;E:\JDK1.8.301\jre\lib\jfxswt.jar;E:\JDK1.8.301\jre\lib\jsse.jar;E:\JDK1.8.301\jre\lib\management-agent.jar;E:\JDK1.8.301\jre\lib\plugin.jar;E:\JDK1.8.301\jre\lib\resources.jar;E:\JDK1.8.301\jre\lib\rt.jar;C:\Users\13288\Desktop\heiMaProject\springIOC_Anno20210824\target\test-classes;C:\Users\13288\.m2\repository\mysql\mysql-connector-java\5.1.32\mysql-connector-java-5.1.32.jar;C:\Users\13288\.m2\repository\junit\junit\4.11\junit-4.11.jar;C:\Users\13288\.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\13288\.m2\repository\com\alibaba\druid\1.1.10\druid-1.1.10.jar;C:\Users\13288\.m2\repository\c3p0\c3p0\0.9.1.2\c3p0-0.9.1.2.jar" com.intellij.rt.junit.JUnitStarter -ideVersion5 -junit4 com.sadhu.config.DataSourseConfiguration,test1
八月 24, 2021 5:19:38 下午 com.mchange.v2.log.MLog <clinit>
信息: MLog clients using java 1.4+ standard logging.
八月 24, 2021 5:19:39 下午 com.mchange.v2.c3p0.C3P0Registry banner
信息: Initializing c3p0-0.9.1.2 [built 21-May-2007 15:04:56; debug?true; trace: 10]
八月 24, 2021 5:19:39 下午 com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource getPoolManager
信息: Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, dataSourceName -> 31snbdajx58efk1sewirk|379619aa, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> null, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 31snbdajx58efk1sewirk|379619aa, idleConnectionTestPeriod -> 0, initialPoolSize -> 3, jdbcUrl -> jdbc:mysql://localhost:33061, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 15, maxStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 3, numHelperThreads -> 3, numThreadsAwaitingCheckoutDefaultUser -> 0, preferredTestQuery -> null, properties -> {user=******, password=******}, propertyCycle -> 0, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> false ]
八月 24, 2021 5:20:09 下午 com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run
警告: [email protected]a6 -- 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: 
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.
	at sun.reflect.GeneratedConstructorAccessor6.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
	at com.mysql.jdbc.Util.getInstance(Util.java:383)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1023)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:997)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:983)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:928)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2576)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2309)
	at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
	at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
	at sun.reflect.GeneratedConstructorAccessor7.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
	at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:419)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344)
	at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)
	at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)
	at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)
	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)
	at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)
	at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)
	at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)
	at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
Caused by: java.lang.NullPointerException
	at com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:3299)
	at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1967)
	at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1893)
	at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1287)
	at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2494)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2527)
	... 17 more

八月 24, 2021 5:20:09 下午 com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run
警告: [email protected]db -- 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: 
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.
	at sun.reflect.GeneratedConstructorAccessor6.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
	at com.mysql.jdbc.Util.getInstance(Util.java:383)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1023)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:997)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:983)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:928)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2576)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2309)
	at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
	at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
	at sun.reflect.GeneratedConstructorAccessor7.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
	at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:419)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344)
	at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)
	at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)
	at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)
	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)
	at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)
	at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)
	at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)
	at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
Caused by: java.lang.NullPointerException
	at com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:3299)
	at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1967)
	at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1893)
	at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1287)
	at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2494)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2527)
	... 17 more

八月 24, 2021 5:20:09 下午 com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask run
警告: [email protected]4d -- 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: 
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.
	at sun.reflect.GeneratedConstructorAccessor6.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
	at com.mysql.jdbc.Util.getInstance(Util.java:383)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1023)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:997)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:983)
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:928)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2576)
	at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2309)
	at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
	at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
	at sun.reflect.GeneratedConstructorAccessor7.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
	at com.mysql.jdbc.Util.handleNewInstance(Util.java:408)
	at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:419)
	at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:344)
	at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)
	at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:182)
	at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:171)
	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:137)
	at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1014)
	at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)
	at com.mchange.v2.resourcepool.BasicResourcePool$AcquireTask.run(BasicResourcePool.java:1810)
	at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:547)
Caused by: java.lang.NullPointerException
	at com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:3299)
	at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1967)
	at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1893)
	at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1287)
	at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2494)
	at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2527)
	... 17 more


java.sql.SQLException: Connections could not be acquired from the underlying database!

	at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:529)
	at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java:128)
	at com.sadhu.config.DataSourseConfiguration.test1(DataSourseConfiguration.java:17)
	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:498)
	at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
	at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
	at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
	at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
	at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:271)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:70)
	at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
	at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
	at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
	at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
	at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
	at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
	at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
	at org.junit.runner.JUnitCore.run(JUnitCore.java:160)
	at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:69)
	at com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
	at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:235)
	at com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:54)
Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.
	at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319)
	at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java:557)
	at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java:477)
	at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java:525)
	... 24 more


Process finished with exit code -1

 

reason

The package version of the connection data is too low

Solution:

You can use a higher version

after modification, you can pass