相等类之间的ClassCastException Wildfly 10 [英] ClassCastException in between equal classes Wildfly 10

问题描述

我正在创建RESTful应用程序，但无法进行新连接的转换。
我的应用程序服务器是Wildfly 10.0。

I am Creating a RESTful application and I am having trouble making a conversion for a new connection. My application server is Wildfly 10.0.

standalone-full.xml中的数据源和驱动程序：

<datasource jndi-name="java:jboss/datasources/PostgreDS" pool-name="PostgreDS" enabled="true" use-java-context="true">
    <connection-url>jdbc:postgresql://192.168.0.112:5432/bdns</connection-url>
    <driver>postgresql</driver>
    <transaction-isolation>TRANSACTION_READ_COMMITTED</transaction-isolation>
    <pool>
        <min-pool-size>10</min-pool-size>
        <max-pool-size>40</max-pool-size>
        <prefill>true</prefill>
    </pool>
    <security>
        <user-name>sa</user-name>
        <password>000000</password>
    </security>
    <statement>
        <prepared-statement-cache-size>32</prepared-statement-cache-size>
        <share-prepared-statements>true</share-prepared-statements>
    </statement>
</datasource>
<drivers>
    <driver name="postgresql" module="org.postgresql">
        <xa-datasource-class>org.postgresql.xa.PGXADataSource</xa-datasource-class>
    </driver>
</drivers>

Java代码ConnectionMng.java：

package dao;

import java.sql.Connection;
import java.sql.SQLException;

import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.sql.DataSource;

import org.jboss.jca.adapters.jdbc.jdk7.WrappedConnectionJDK7;
import org.postgresql.jdbc.PgConnection;

public class ConnectionMng {
    private DataSource ds;

    private ConnectionMng() throws NamingException {
        this.ds = (DataSource)new InitialContext().lookup("java:jboss/datasources/PostgreDS");
    }

    public PgConnection getPgConnection() throws SQLException {
        WrappedConnectionJDK7 wrappedConn = (WrappedConnectionJDK7)ds.getConnection();
        Connection underlyingConn = wrappedConn.getUnderlyingConnection(); 
        return (PgConnection)underlyingConn;
    }
}

发生异常：

ClassCastException: org.jboss.jca.adapters.jdbc.jdk7.WrappedConnectionJDK7 cannot be cast to org.jboss.jca.adapters.jdbc.jdk7.WrappedConnectionJDK7

pom.xml：

<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>Core</groupId>
<artifactId>Core</artifactId>
<version>1.0.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>Core</name>
<description>Core</description>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <java.version>1.8</java.version>
    <javac.target>1.8</javac.target>
    <postgresql.enforce.jdk.version>[1.7,1.8)</postgresql.enforce.jdk.version>
</properties>

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.3.3.RELEASE</version>
</parent>

<dependencies>
    <dependency>
        <groupId>org.wildfly</groupId>
        <artifactId>wildfly-connector</artifactId>
        <version>10.0.0.Final</version>
    </dependency>
    <dependency>
        <groupId>org.postgresql</groupId>
        <artifactId>postgresql</artifactId>
    </dependency>
    <dependency>
        <groupId>javax</groupId>
        <artifactId>javaee-api</artifactId>
        <version>7.0</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
        <exclusions>
            <exclusion>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-tomcat</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-dbcp2</artifactId>
    </dependency>
    <dependency>
        <groupId>org.codehaus.jackson</groupId>
        <artifactId>jackson-mapper-asl</artifactId>
        <version>1.9.13</version>
    </dependency>
    <dependency>
        <groupId>org.apache.poi</groupId>
        <artifactId>poi-ooxml</artifactId>
        <version>3.12</version>
    </dependency>
    <dependency>
        <groupId>commons-fileupload</groupId>
        <artifactId>commons-fileupload</artifactId>
        <version>1.3.1</version>
    </dependency>
    <dependency>
        <groupId>com.thoughtworks.xstream</groupId>
        <artifactId>xstream</artifactId>
        <version>1.4.8</version>
    </dependency>
    <dependency>
        <groupId>com.github.junrar</groupId>
        <artifactId>junrar</artifactId>
        <version>0.7</version>
    </dependency>
    <dependency>
        <groupId>org.zeroturnaround</groupId>
        <artifactId>zt-zip</artifactId>
        <version>1.9</version>
        <type>jar</type>
        <exclusions>
            <exclusion>
                <groupId>org.slf4j</groupId>
                <artifactId>slf4j-log4j12</artifactId>
            </exclusion>
            <exclusion>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
</dependencies>

<build>
    <sourceDirectory>src</sourceDirectory>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
        <plugin>
            <artifactId>maven-war-plugin</artifactId>
            <configuration>
                <warSourceDirectory>WebContent</warSourceDirectory>
                <failOnMissingWebXml>false</failOnMissingWebXml>
            </configuration>
        </plugin>
    </plugins>
</build>

推荐答案

aribeiro的答案是正确的答案：一个由build-tool（Maven）打包的jar位于战争的lib目录中，并且与wildfly-Classloader冲突。

The answer from aribeiro is the right answer: A jar, packaged by the build-tool(Maven) is in the lib-directory of the war and conflicts with the wildfly-Classloader.

此外，以下问题的通用解决方案：

Additional,here is a generic solution for the following issue:

• 您已经拥有JBoss 7 AS或Wildfly AS


• 您使用Eclipse JBoss Tools


• 您部署了EAR或WAR，lib-Folder由Maven之类的构建工具打包


• 会出现这样的错误：examplepackage.ExcampleClass无法转换为examplepackage.ExcampleClass

• you've got a JBoss 7 AS or a Wildfly AS
• You work with Eclipse JBoss Tools
• you deploy an EAR or a WAR, lib-Folder is packed by build-tool like Maven
• there occurs an error like this: examplepackage.ExcampleClass cannot be cast to examplepackage.ExcampleClass

大多数情况是在您离开Java EE-Spec并使用特定于JBoss / Wildfly的模块，ironjacamar，jsf-impl等时发生的。 Maven将所需的jar放在lib目录中。但是Jars已经在AS的模块目录中。根据我的经验， ClassCastException 出于这个原因而发生。

Mostly it happens, when you leave the Java EE-Spec and use JBoss/Wildfly-specific modules, ironjacamar, jsf-impl and so on. Maven puts the required jars in the lib-directory. But the Jars are already in the module-directory of the AS. According to my experience, the ClassCastException occurs for this reason.

然后必须从lib-中删除jar。

You must then remove the jar from the lib-directory, in maven by declaring the dependency as provided.

告诉JBoss / Wildfly-Classloader在哪里找到该类。可以通过以下方式完成：

Tell the JBoss/Wildfly-Classloader, where to find the class. This can be done by:

• 向 MANIFEST.MF 的项目。 Eclipse-JBoss-Tools从服务器环境中加载类，因此您可以从pom中删除依赖项。在您的情况下：

• Either add a dependency to the MANIFEST.MF of the project. Eclipse-JBoss-Tools loads the class from the Server-Enviroment, so you can remove the dependency from the pom. In your case:

Dependencies: org.jboss.ironjacamar.jdbcadapters

或者您使用 jboss-deployment-structure.xml ，则可以加载该类与Maven，但声明为已提供

Or you use the jboss-deployment-structure.xml, then you can load the class with Maven, but declare it as provided

<dependencies>
    <module name="org.jboss.ironjacamar.jdbcadapters" />
</dependencies>

另请参见 https://docs.jboss.org/author/display/WFLY8/Class+Loading+in + WildFly

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