Tag Archives: report errors

Springboot project: error parsing HTTP request header note: further occurrences of HTTP request parsing

There is no error reported after the spirngboot project is started, but when testing the interface with postman, it is found that there will be intermittent (one good and one bad) errors

Error parsing HTTP request header
 Note: further occurrences of HTTP request parsing errors will be logged at DEBUG level.
java.lang.IllegalArgumentException : Invalid character found in method name. HTTP method names must be tokens

Simple appearance is also very normal, it is a success, a mistake, make me at a loss.

Looking up the online materials, 98% of them said that the configuration change of the maximum header value of Tomcat would be good, but springboot is built-in Tomcat,

The method of modification is as follows: sever.tomcat.max -http-header-size=8192

But this configuration has been abandoned by the boot project of higher version,

It can be changed to: sever.max -http-header-size=8192

Full of joy, thought that good, and then found No.

The other 2% said it might be related to the HTTPS protocol, so it could be changed to http.

But I started it locally. It’s always http.

After struggling for a long time, I found that the culprit actually added content length to the header when requesting and gave it a fixed value, so I would report an error. Stupid cry~~

As for the function of modifying the max HTTP header size, I set this to 1 and request again to find that the error reported is not the same as my previous one, but:

Error processing request
org.apache.coyote .http11.HeadersTooLargeException: An attempt was made to write more data to the response headers than there was room available in the buffer.

Tensorflow error: attributeerror: module ‘tensorflow’ has no attribute ‘unpack’ (‘pack ‘)

Tensorflow: attributeerror: module ‘tensorflow’ has no attribute ‘unpack’ (‘pack ‘)

As shown in the figure:

AttributeError: module ‘tensorflow’ has no attribute ‘unpack’

Analysis: after tensorflow version 1.0 + is updated, the method name changes

Solution:

error report

before update

after update

attributeerror: module ‘tensorflow’ has no attribute ‘unpack’

after update tf.unpack () tf.unstack ()
AttributeError: module ‘tensorflow’ has no attribute ‘pack’ tf.pack () tf.stack ()

Wamp Apache can’t run error report could not execute menu item

wamp:could not Execute menu item (internal error) [exception] count not perform service action: the server did not respond to the start or control request in time

At present, there are basically two other types on the Internet: the port number is occupied and the file cannot be found

This problem is hardly found on the Internet

Only Apache can’t start, the error is shown in the figure.
Solution: start manually in the service.
Start the service: services.msc

Start the wampaache service manually

Jupyter failed to run websocket error

Juputer cannot connect

There is a problem with the websocket connection, the browser console reports an error, and the WS connection is abnormal

WebSocket connection to 'ws:// localhost:8888/api/kernels/f8809bf9-988f-4666-b183-e01bed63fa76/channels?session_ id=e49c21f065e64e7a89847a0859d689dd' failed: Error during WebSocket handshake: Unexpected response code: 200

Solution

Refer to https://github.com/jupyter/notebook/issues/4399

Uninstall tornado 6 and re install tornado 5.

pip uninstall tornado
pip install tornado==5.1.1

Spring security failed to log in, error: there is no passwordencoder mapped for the ID “null”

After writing the websecurityconfig class that inherits the websecurityconfigureradapter class, we need to define authentication in the configure (authentication manager builder auth) method, which is used to obtain information sources and password verification rules. (the name of the configure function doesn’t matter. The official name seems to be configureglobal (…) ）It is important to configure the authenticationmanagerbuilder in the class annotated by @ enablewebsecurity or @ enableglobalmethodsecurity or @ enableglobalauthentication).

The source of authentication information I used at the beginning was in memory authentication. The code is as follows

 
    protected void configure (authentication manager auth) throws exception { // inmemoryauthentication gets from memory auth.inMemoryAuthentication ().withUser("user1").password("123456").roles("USER"); }

The login page of spring security is used. As a result, when logging in, the user name and password are correct, and the resource cannot be opened, so it still stays on the login page. There is no passwordencoder mapped for the ID "null".

Baidu found that this is because spring security 5.0 added a variety of encryption methods, but also changed the password format.

Let's take a look at the official documents. Here are the original words of the official documents:

 

-------------------------------------------------------------------------------------------------------------------

The general format for a password is:

{id}encodedPassword

Such that id is an identifier used to look up which PasswordEncoder should be used and encodedPassword is the original encoded password for the selected PasswordEncoder. The id must be at the beginning of the password, start with { and end with }. If the id cannot be found, the id will be null. For example, the following might be a list of passwords encoded using different id. All of the original passwords are "password".

{bcrypt}$2a$10$dXJ3SW6G7P50lGmMkkmwe.20cQQubK3.HZWzG3YB1tlRy.fqvM/BG 
{noop}password 
{pbkdf2}5d923b44a6d129f3ddf3e3c8d29412723dcbde72445e8ef6bf3b508fbf17fa4ed4d6b99ca763d8dc 
{scrypt}$e0801$8bWJaSu2IKSn9Z9kM+TPXfOc/9bdYSrN1oD9qfVThWEwdRTnO7re7Ei+fUZRJ68k9lTyuTeUp4of4g24hHnazw==$OAOec05+bXxvuu/1qZ6NUR+xQYvYv7BeL1QxwRpY5Pc=  
{sha256}97cde38028ad898ebc02e690819fa220e88c62e0699403e94fff291cfffaf8410849f27605abcbc0

-------------------------------------------------------------------------------------------------------------------

 

The storage format of passwords in spring security is "{ID}.....". The front ID is the encryption method, the ID can be bcrypt, sha256, etc., followed by the encrypted password. In other words, when the program gets the passed password, it will first find the ID included by "{" and "}" to determine how the subsequent password is encrypted. If it cannot be found, it will be considered that the ID is null. This is why our program will report an error: there is no passwordencoder mapped for the ID "null". In the example of official documents, various encryption methods are used to encrypt the same password. The original password is "password".

 

If we want our project to log in normally, we need to modify the code in configure. We need to encrypt the password from the front end in some way. Spring security officially recommends using bcrypt encryption. So how to encrypt the password?Just specify it in the configure method.

After modification, it looks like this:

 
    protected void configure (authentication manager auth) throws exception { // inmemoryauthentication gets from memory auth.inMemoryAuthentication ().passwordEncoder(new BCryptPasswordEncoder()).withUser("user1").password(new BCryptPasswordEncoder().encode("123456")).roles("USER"); }

After inmemoryauthentication(), there is ". Passwordencoder (New bcryptpasswordencoder())", which is equivalent to using bcrypt encryption to process the user password when logging in. The previous ". Password (" 123456 ")" is changed to ". Password (New bcryptpasswordencoder(). Encode (" 123456 ")", which is equivalent to bcrypt encoding and encryption of the password in memory. The comparison is consistent, which indicates that the password is correct and login is allowed.

If you are also using the password from the memory, then according to the above modification should be successful login, no problem.

If you use to store the user name and password in the database, you usually use bcrypt code to encrypt the user password and store it in the database. And modify the configure() method, add ". Passwordencoder (New bcryptpasswordencoder())" to ensure that users use bcrypt to process the password when they log in, and then compare it with the password in the database. As follows:

 
    // inject the implementation class of userdetailsservice auth.userDetailsService (userService).passwordEncoder(new BCryptPasswordEncoder());
     

reprint https://blog.csdn.net/canon_ in_ d_ major/article/details/79675033

This function has none of deterministic, no SQL, or reads SQL data in its error records

This function has none of DETERMINISTIC, NO SQL, or READS SQL DATA in its declaration and binary logging is enabled (you *might* want to use the less safe log_ bin_ trust_ function_ creators variable)

The solution to this error when creating a function in MySQL:
set global log_ bin_ trust_ function_ Creators = true;
it should be noted that it is invalid after restarting the service.

Mybatis error,There is no getter for property named ‘xx’ in ‘class java.lang.String The solution

Today, I encountered a problem when using mybatis. When passing a string parameter, I encountered the following error:

Mapper.xml The code is as follows:

Error report when executing this method:

Maven is used for project jar management, and mybatis version is as follows (I use mybatis plus plug-in)

After browsing the data for half a day on the Internet, we found a solution. We need to use the_ The parameter is replaced uniformly. We modify the previous code as follows:

This is because of the version limitation of mybatis. You may not have this situation in some versions (I don’t understand very well here. Thank you )

Summary of common runtimeException exceptions

Common runtimeException summary in development or interview

The common types are as follows:

 

NullPointerException – null pointer reference exception
ClassCastException – type cast exception.
Illegalargumentexception – pass illegal parameter exception.
Arithmeticexception – arithmetic operation exception
arraystoreexception – storing objects incompatible with declared types into an array exception
indexoutofboundsexception – subscript out of bounds exception
negativearraysizeexception – creating an array with negative size error exception
numberformatexception – number format exception
SecurityException – Security Exception
exception Unsupported operationexception – unsupported operation exception

 

Arithmetic exception class: arithmeticexception
null pointer exception class: NullPointerException
type coercion exception: ClassCastException
array negative subscript exception: negativearrayexception
array subscript out of bounds exception: ArrayIndexOutOfBoundsException
security violation exception: SecurityException
file ended exception: eofexception
exception File not found exception: FileNotFoundException
string converted to number exception: numberformatexception
operation database exception: sqlexception
input/output exception: IOException
method not found exception: nosuchmethodexception

Java.lang.AbstractMethodError
Abstract method error. Thrown when an application attempts to call an abstract method.

java.lang.AssertionError
Wrong assertion. Used to indicate the failure of an assertion.

java.lang.ClassCircularityError
Class loop dependency error. When initializing a class, if a circular dependency between classes is detected, the exception is thrown.

java.lang.ClassFormatError
Class format error. Thrown when the Java virtual machine attempts to read a Java class from a file and detects that the contents of the file do not conform to the valid format of the class.

java.lang.Error
Wrong. Is the base class for all errors and is used to identify serious program running problems. These problems usually describe anomalies that should not be captured by the application.

java.lang.ExceptionInInitializerError
Initializer error. Thrown when an exception occurs during the execution of a class’s static initializer. Static initializers are static statements directly contained in classes.

java.lang.IllegalAccessError
Illegal access error. When an application attempts to access, modify the field of a class or call its method, but violates the visibility declaration of the field or method, it throws the exception.

java.lang.IncompatibleClassChangeError
Incompatible class change error. This exception is thrown when the class definition on which the executing method depends is changed incomparably. Generally, it is easy to cause this error when the declaration definition of some classes in the application is modified without recompiling the whole application.

java.lang.InstantiationError
Instantiation error. This exception is thrown when an application attempts to construct an abstract class or interface through Java’s new operator.

this exception is thrown java.lang.InternalError
Internal error. Used to indicate that an internal error has occurred in the Java virtual machine.

java.lang.LinkageError
Link error. This error and all its subclasses indicate that a class depends on other classes. After the class is compiled, the dependent class changes its class definition and does not recompile all the classes, thus causing an error.

java.lang.NoClassDefFoundError
Class definition error not found. This error is thrown when a Java virtual machine or class loader attempts to instantiate a class and cannot find its definition.

java.lang.NoSuchFieldError
There are no errors in the domain. This error is thrown when an application attempts to access or modify a domain of a class, but there is no definition of the domain in the definition of the class.

java.lang.NoSuchMethodError
Method has no errors. This error is thrown when an application attempts to call a method of a class and there is no definition of the method in the definition of the class.

java.lang.OutOfMemoryError
Out of memory error. This error is thrown when the available memory is insufficient for the Java virtual machine to allocate to an object.

java.lang.StackOverflowError
Stack overflow error. This error is thrown when the level of an application recursive call is too deep to cause a stack overflow.

java.lang.ThreadDeath
The thread ends. This error is thrown when the stop method of the thread class is called to indicate the end of the thread.

java.lang.UnknownError
Unknown error. Used to indicate that an unknown fatal error has occurred in the Java virtual machine.

java.lang.UnsatisfiedLinkError
Unsatisfied link error. Thrown when the Java virtual machine does not find a native language definition of a class declared as a native method.

java.lang.UnsupportedClassVersionError
Unsupported class version error. When the Java virtual machine attempts to read a class file from, but finds that the major and minor version numbers of the file are not supported by the current Java virtual machine, this error is thrown.

java.lang.VerifyError
Validation error. This error is thrown when the verifier detects an internal incompatibility or security problem in a class file.

java.lang.VirtualMachineError
Virtual machine error. It is used to indicate that the virtual machine is damaged or insufficient resources are needed to continue the operation.

java.lang.ArithmeticException
The arithmetic condition is abnormal. For example: integer divided by zero and so on.

java.lang.ArrayIndexOutOfBoundsException
Array index out of bounds exception. Thrown when the index value to the array is negative or greater than or equal to the size of the array.

java.lang.ArrayStoreException
Array storage exception. Thrown when a non array declaration type object is placed in an array.

java.lang.ClassCastException
Class shape exception. Suppose that there are classes a and B (a is not the parent or child of B), and O is an instance of a, then this exception will be thrown when o is forced to be constructed as an instance of class B. This exception is often referred to as a cast exception.

java.lang.ClassNotFoundException
Class exception not found. When the application attempts to construct a class according to the class name in the form of a string, and cannot find the class file with the corresponding name after traversing the classpath, it throws this exception.

java.lang.CloneNotSupportedException
Clone exception is not supported. When the Cloneable interface is not implemented or the clone method is not supported, the clone () method will throw this exception.

java.lang.EnumConstantNotPresentException
Enumeration constant has no exception. This exception is thrown when an application attempts to access an enumeration object by name and enumeration type, but the enumeration object does not contain a constant.

java.lang.Exception
Root exception. Describes what the application wants to capture.

java.lang.IllegalAccessException
Illegal access exception. This exception is thrown when an application attempts to create an instance of a class, access its properties, and call its methods through reflection, but it cannot access the definition of class, property, method, or construction method.

java.lang.IllegalMonitorStateException
Illegal monitoring status is abnormal. This exception is thrown when a thread tries to wait for a monitor of an object (o) that it does not own, or notifies other threads to wait for the monitor of the object (o).

java.lang.IllegalStateException
The illegal state is abnormal. When the Java environment and application are not in the legal calling state of a method, and the method is called, the exception is thrown.

java.lang.IllegalThreadStateException
Illegal thread state exception. When a method is called while it is not in legal calling state, an exception is thrown.

java.lang.IndexOutOfBoundsException
Index out of bounds exception. When the index value of accessing a sequence is less than 0 or greater than or equal to the sequence size, the exception is thrown.

java.lang.InstantiationException
Instantiation exception. This exception is thrown when an attempt is made to create an instance of a class that is an abstract class or interface through the newinstance() method.

java.lang.InterruptedException
Aborted exception. When a thread is in a long waiting, sleeping or other pause state, and other threads terminate the thread through the interrupt method of thread, this exception is thrown.

java.lang.NegativeArraySizeException
Negative array size exception. This exception is thrown when an array is created with a negative size value.

java.lang.NoSuchFieldException
Property has no exception. This exception is thrown when accessing a nonexistent property of a class.

java.lang.NoSuchMethodException
Method has no exception. This exception is thrown when a nonexistent method of a class is accessed.

java.lang.NullPointerException
Null pointer exception. This exception is thrown when the application attempts to use null where the object is required. For example: call instance method of null object, access property of null object, calculate length of null object, throw null with throw statement, etc.

java.lang.NumberFormatException
The number format is abnormal. This exception is thrown when an attempt is made to convert a string to a specified numeric type and the string does not meet the format required by the numeric type.

java.lang.RuntimeException
Runtime exception. Is the parent of all exceptions that can be thrown during normal operation of Java virtual machine.

java.lang.SecurityException
Security exception. An exception thrown by the security manager to indicate a security violation.

java.lang.StringIndexOutOfBoundsException
String index out of bounds exception. When the index value is used to access characters in a string and the index value is less than 0 or greater than or equal to the sequence size, the exception is thrown.

java.lang.TypeNotPresentException
There is no exception for the type. This exception is thrown when an application attempts to access a type in a string representation of the type name, but cannot find the type according to the given name. The difference between this exception and classnotfoundexception is that it is an unchecked exception, while classnotfoundexception is a checked exception.

java.lang.UnsupportedOperationException
Unsupported method exception. Exception indicating that the requested method is not supported.

org.springframework.dao.InvalidDataAccessApiUsageException: Bean object must not be null; nested exc

An error is reported when the project is started, and the entity class is null

org.springframework.dao.InvalidDataAccessApiUsageException: Bean object must not be null; nested exception is java.lang.IllegalArgumentException: Bean object must not be null
	at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:296)
	at org.springframework.orm.jpa.vendor.HibernateJpaDialect.translateExceptionIfPossible(HibernateJpaDialect.java:108)
	at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:403)
	at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:58)
	at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213)
	at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:163)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.data.jpa.repository.support.LockModeRepositoryPostProcessor$LockModePopulatingMethodIntercceptor.invoke(LockModeRepositoryPostProcessor.java:92)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:91)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
	at com.sun.proxy.$Proxy22.save(Unknown Source)
	at cn.zx.ghjmaven.service.EmployeeServiceImpl.save(EmployeeServiceImpl.java:17)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
	at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96)
	at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:204)
	at com.sun.proxy.$Proxy26.save(Unknown Source)
	at cn.zx.ghjmaven.action.bc.EmployeeAction.save(EmployeeAction.java:35)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:450)
	at com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:289)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:252)
	at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:167)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:265)
	at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:138)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:239)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:239)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:191)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:73)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:91)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:252)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:100)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:141)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)
	at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:161)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:193)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:189)
	at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:246)
	at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
	at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:563)
	at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
	at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:99)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
	at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607)
	at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:313)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.IllegalArgumentException: Bean object must not be null
	at org.springframework.util.Assert.notNull(Assert.java:112)
	at org.springframework.beans.BeanWrapperImpl.setWrappedInstance(BeanWrapperImpl.java:213)
	at org.springframework.beans.BeanWrapperImpl.setWrappedInstance(BeanWrapperImpl.java:202)
	at org.springframework.beans.BeanWrapperImpl.<init>(BeanWrapperImpl.java:151)
	at org.springframework.data.jpa.repository.support.JpaMetamodelEntityInformation$DirectFieldAccessFallbackBeanWrapper.<init>(JpaMetamodelEntityInformation.java:261)
	at org.springframework.data.jpa.repository.support.JpaMetamodelEntityInformation.getId(JpaMetamodelEntityInformation.java:107)
	at org.springframework.data.repository.core.support.AbstractEntityInformation.isNew(AbstractEntityInformation.java:51)
	at org.springframework.data.jpa.repository.support.JpaMetamodelEntityInformation.isNew(JpaMetamodelEntityInformation.java:190)
	at org.springframework.data.jpa.repository.support.SimpleJpaRepository.save(SimpleJpaRepository.java:357)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.executeMethodOn(RepositoryFactorySupport.java:344)
	at org.springframework.data.repository.core.support.RepositoryFactorySupport$QueryExecutorMethodInterceptor.invoke(RepositoryFactorySupport.java:329)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:96)
	at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:260)
	at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:94)
	at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
	at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:155)
	... 91 more

Research on Maven management of Java project pom.xml The jar package error is reported, but the project is running normally

Today, I always make mistakes when building projects. I suspect that there is something wrong with the jar package, so I delete all the jar packages and reload them into the Maven warehouse,

Think very good, but made a mistake! POM file error, how to update all useless, delete jar package reload also can’t.

Finally, in the life and death of the occasion, choose the forced refresh, just like, then remember it!

Eclipse port occupied（ java.net.BindException : address already in use: bind) solution

An error occurred when starting Tomcat in Eclipse: the port is already occupied.

This is because when Tomcat is on, eclipse closes abnormally, causing Tomcat to occupy the port all the time.

resolvent

Enter the command in the CMD window–

Netstat – ano | findstr 8080 (8080 refers to the occupied port number)

After the command is executed, you can get the PID of the process that occupies the changed port number

Then enter the command in the CMD window–

Taskkill – PID – F from the last command

ok

java.lang.IllegalStateException Exception: cause analysis and solution

Today, I write a java file download program. After it’s finished, everything is normal, but it always throws out java.lang.IllegalStateException Abnormal, although it does not affect the normal use, but it always makes people feel very uncomfortable. There is nothing wrong with checking the code. Finally, I checked a lot of information on the Internet and finally found out the reason.

When we upload or download files, or filter files, we may need to use the output stream of the page.
for example, when we use it in action:
for example, when we use it in action response.reset ();
　　　　 response.setContentType (”application/ vnd.ms -excel”);
　　　　OutputStream os = response.getOutputStream ();
throw an exception: java.lang.IllegalStateException

Cause analysis:
this is a problem in the servlet code generated by the web container out.write (), which is invoked in JSP. response.getOutputStream () conflicts.
that is, the servlet specification states that it cannot be called either response.getOutputStream (), and then call response.getWriter (), no matter which one is called first, an IllegalStateException will be thrown when calling the second one,

Because in JSP, the out variable is generated through the response.getWriter It is used in the program response.getOutputStream , and the out variable is used, so the above error occurs.

solve:

Method 1: add the following two sentences to the JSP file

<%
out.clear ();
out = pageContext.pushBody ();
%>

Defects of this method:
many development projects are not caused by JSP front-end, such as freemaker, velocity and so on“ response.getOutputStream () “not in JSP, but in servlet/action

Method 2: in action, do not return to the specific result file, return null
instead

//return SUCCESS;
return null;