我正在尝试在HttpServlet中使用ActiveJDBC-我知道数据库连接需要在单独的线程上打开，并且can be done through a WebFilter.
不幸的是，我无法看到此错误消息：
例外
javax.servlet.ServletException：筛选器执行引发异常 根本原因
java.lang.NoClassDefFoundError：无法初始化类 org.javalite.activejdbc.Registry org.javalite.activejdbc.DB.open（DB.java:152） org.javalite.activejdbc.Base.open（Base.java:51） filter.DBFilter.doFilter（DBFilter.java:13）
完整错误堆栈：
java.lang.NoClassDefFoundError: Could not initialize class org.javalite.activejdbc.Registry
at org.javalite.activejdbc.DB.open(DB.java:152)
at org.javalite.activejdbc.Base.open(Base.java:51)
at filters.DBFilter.init(DBFilter.java:17)
at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:270)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:251)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:102)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4491)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5135)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:743)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:719)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:703)
at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:986)
at org.apache.catalina.startup.HostConfig$DeployWar.run(HostConfig.java:1858)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.base/java.util.concurrent.FutureTask.run(Unknown Source)
at org.apache.tomcat.util.threads.InlineExecutorService.execute(InlineExecutorService.java:75)
at java.base/java.util.concurrent.AbstractExecutorService.submit(Unknown Source)
at org.apache.catalina.startup.HostConfig.deployWARs(HostConfig.java:772)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:426)
at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1629)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:304)
at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:123)
at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1176)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1398)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1402)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1370)
at java.base/java.lang.Thread.run(Unknown Source)
这是我的filter.DBFilter类：
package filters;
import org.javalite.activejdbc.Base;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import java.io.IOException;
@WebFilter("/DBFilter")
public class DBFilter implements Filter {
@Override
public void doFilter(final ServletRequest request, final ServletResponse response, FilterChain chain) throws IOException, ServletException {
Base.open();
chain.doFilter(request,response);
Base.close();
}
}
并完成.classpath：
<?xml version="1.0" encoding="UTF-8"?>
<classpath>
<classpathentry kind="src" output="target/classes" path="src/main/java">
<attributes>
<attribute name="optional" value="true"/>
<attribute name="maven.pomderived" value="true"/>
</attributes>
</classpathentry>
<classpathentry excluding="**" kind="src" output="target/classes" path="src/main/resources">
<attributes>
<attribute name="maven.pomderived" value="true"/>
</attributes>
</classpathentry>
<classpathentry kind="src" output="target/test-classes" path="src/test/java">
<attributes>
<attribute name="optional" value="true"/>
<attribute name="maven.pomderived" value="true"/>
<attribute name="test" value="true"/>
</attributes>
</classpathentry>
<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8">
<attributes>
<attribute name="maven.pomderived" value="true"/>
</attributes>
</classpathentry>
<classpathentry kind="con" path="org.eclipse.m2e.MAVEN2_CLASSPATH_CONTAINER">
<attributes>
<attribute name="maven.pomderived" value="true"/>
</attributes>
</classpathentry>
<classpathentry kind="src" path="target/generated-sources/annotations">
<attributes>
<attribute name="optional" value="true"/>
<attribute name="maven.pomderived" value="true"/>
<attribute name="ignore_optional_problems" value="true"/>
<attribute name="m2e-apt" value="true"/>
</attributes>
</classpathentry>
<classpathentry kind="src" output="target/test-classes" path="target/generated-test-sources/test-annotations">
<attributes>
<attribute name="optional" value="true"/>
<attribute name="maven.pomderived" value="true"/>
<attribute name="ignore_optional_problems" value="true"/>
<attribute name="m2e-apt" value="true"/>
<attribute name="test" value="true"/>
</attributes>
</classpathentry>
<classpathentry kind="output" path="target/classes"/>
</classpath>
并完成pom.xml：
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.ticketsit</groupId>
<artifactId>ticketsit</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>ticketsit Maven Webapp</name>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<java.version>1.8</java.version>
<environments>development.test,development</environments>
<maven.compiler.source>${java.version}</maven.compiler.source>
<maven.compiler.target>${java.version}</maven.compiler.target>
</properties>
<dependencies>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>javax.annotation</groupId>
<artifactId>javax.annotation-api</artifactId>
<version>1.2</version>
</dependency>
<dependency>
<groupId>org.javalite</groupId>
<artifactId>activejdbc</artifactId>
<version>2.0</version>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-crypto</artifactId>
<version>5.1.1.RELEASE</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.13</version>
</dependency>
<dependency>
<groupId>org.javalite</groupId>
<artifactId>activejdbc-instrumentation</artifactId>
<version>2.0</version>
</dependency>
</dependencies>
<build>
<finalName>ticketsit</finalName>
<resources>
<resource>
<directory>${basedir}/src/main/resources</directory>
<excludes><exclude>node_modules/**</exclude></excludes>
</resource>
</resources>
<pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
<plugins>
<plugin>
<groupId>org.javalite</groupId>
<artifactId>activejdbc-instrumentation</artifactId>
<version>2.0</version>
<executions>
<execution>
<phase>process-classes</phase>
<goals>
<goal>instrument</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<artifactId>maven-clean-plugin</artifactId>
<version>3.0.0</version>
</plugin>
<!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
<plugin>
<artifactId>maven-resources-plugin</artifactId>
<version>3.0.2</version>
</plugin>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.7.0</version>
</plugin>
<plugin>
<artifactId>maven-surefire-plugin</artifactId>
<version>2.20.1</version>
</plugin>
<plugin>
<artifactId>maven-war-plugin</artifactId>
<version>3.2.0</version>
</plugin>
<plugin>
<artifactId>maven-install-plugin</artifactId>
<version>2.5.2</version>
</plugin>
<plugin>
<artifactId>maven-deploy-plugin</artifactId>
<version>2.8.2</version>
</plugin>
</plugins>
</pluginManagement>
</build>
</project>
有什么想法吗？谢谢。
答案 0 :(得分：0)
您必须设置一个try{} catch{}包装器，可以选择对事务进行包装。不幸的是，错误消息不能完全清楚地揭示此问题！
示例：
@Override
public void doFilter(final ServletRequest request, final ServletResponse response, FilterChain chain) throws IOException, ServletException {
chain.doFilter(request,response);
try{
Base.open();
Base.openTransaction();
chain.doFilter(request, response);
Base.commitTransaction();
}
catch (IOException e){
Base.rollbackTransaction();
throw e;
}
catch (ServletException e){
Base.rollbackTransaction();
throw e;
}
finally{
Base.close();
}
}