Java开发异常

1.org.apache.catalina.LifecycleException

报错信息如下：

警告: Error during context [/wxqhbcloud] restart
org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/wxqhbcloud]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:162)
	at org.apache.catalina.startup.HostConfig.reload(HostConfig.java:1584)
	at org.apache.catalina.startup.HostConfig.checkResources(HostConfig.java:1548)
	at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1784)
	at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:366)
	at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
	at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
	at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1370)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1542)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1552)
	at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1520)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalStateException: Unable to complete the scan for annotations for web application [/wxqhbcloud] due to a StackOverflowError. Possible root causes include a too low setting for -Xss and illegal cyclic inheritance dependencies. The class hierarchy being processed was [org.bouncycastle.asn1.ASN1Boolean->org.bouncycastle.asn1.DERBoolean->org.bouncycastle.asn1.ASN1Boolean]
	at org.apache.catalina.startup.ContextConfig.checkHandlesTypes(ContextConfig.java:2174)
	at org.apache.catalina.startup.ContextConfig.processAnnotationsStream(ContextConfig.java:2120)
	at org.apache.catalina.startup.ContextConfig.processAnnotationsJar(ContextConfig.java:1981)
	at org.apache.catalina.startup.ContextConfig.processAnnotationsUrl(ContextConfig.java:1942)
	at org.apache.catalina.startup.ContextConfig.processAnnotations(ContextConfig.java:1927)
	at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1332)
	at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:888)
	at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:388)
	at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
	at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5522)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
	... 11 more

　　解决：

第一步：修改jvm分配的堆空间。没有解决

在需要运行的程序右键选择Run As -> Run Configurations -> 在打开的Run Configurations中找到VM arguments，输入需要设置的jvm参数，比如：-Xms2048M -Xmx2048M  ->点击Run即可。

第二步：把项目clean一下，然后remove、add再次启动。没有解决

第三步：在web.xml中加上  metadata-complete="true" ，不让tomcat继续扫描jar包 。没有解决

<web-app metadata-complete="true">

　解释见http://qingyuexiao.iteye.com/blog/1886059

 第四步：修改tomcat，禁止扫描

更改tomcat配置文件catalina.properties 。 ->   tomcat.util.scan.DefaultJarScanner.jarsToSkip= 值后面加",*"。

2.Data truncation: Data too long for column 'remark' at row 1

(1)服务器的配置文件

比如tomcat的话，在conf文件下面有，web.xml，server.xml，tomcat-users.xml，context.xml等文件，设置编码为uft-8：<?xml version='1.0' encoding='utf-8'?>

(2)数据库的配置文件

比如mysql的my.ini，设置默认的编码为utf-8：default-character-set=utf8。