Spring导出可以运行的jar包问题如何解决

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最近需要解决Maven项目导入可执行的jar包的问题，如果项目不包含Spring，那么使用mvn assembly:assembly即可

可是如果包含Spring，那么这么方法就不可行，报错：

Configuration problem: Unable to locate Spring NamespaceHandler for XML schema namespace

我在网上折腾了两天，这是assembly的一个bug。

据说原因是spring的多个jar包中都含有spring.handlers和spring.schemas文件，而assembly只会把第一次遇到的文件打入jar包，后面遇到的都会skip掉。

解决方法就是放弃assembly，使用shade插件来打包.在shade的打包配制中指明spring.handlers和spring.schemas文件会以append方式加入进来，从而确保其他spring的jar中的这两个文件的信息不会被遗漏。

下面是一个非常简单的例子，只有四个文件的Maven工程，代码再附件内：

1、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>com.javaee</groupId>
    <artifactId>main-spring</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>3.0.6.RELEASE</version>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>1.7</version>

                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <finalName>my-spring-app</finalName>
                            <shadedArtifactAttached>true</shadedArtifactAttached>
                            <shadedClassifierName>jar-with-dependencies</shadedClassifierName>
                            <transformers>
                                <transformer
                                    implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>com.test.Main</mainClass>
                                </transformer>
                                <transformer
                                    implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                    <resource>META-INF/spring.handlers</resource>
                                </transformer>
                                <transformer
                                    implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                    <resource>META-INF/spring.schemas</resource>
                                </transformer>
                                <transformer
                                    implementation="org.apache.maven.plugins.shade.resource.AppendingTransformer">
                                    <resource>META-INF/spring.tooling</resource>
                                </transformer>
                            </transformers>

                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

2、applicationContext.xml(Spring的配置文件)

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:aop="http://www.springframework.org/schema/aop" xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
        http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
        ">
    <context:annotation-config />
    <context:component-scan base-package="com.*" />
</beans>

3、代码事例

package com.service;

import org.springframework.stereotype.Service;

@Service
public class UserService {
    public String findUser() {
        return "find liqiu";
    }
}

package com.exec;

import org.springframework.context.support.GenericXmlApplicationContext;

import com.service.UserService;

public class Main {

    public static void main(String[] args) throws InterruptedException {
        GenericXmlApplicationContext context = new GenericXmlApplicationContext();
        context.setValidating(false);
        context.load("classpath:applicationContext.xml");
        context.refresh();
        UserService userService = context.getBean(UserService.class);
        while (true) {
            System.out.println(userService.findUser());
            Thread.sleep(10000);
        }
    }
}

在命令行运行：mvn package

然后在target目录会产出一个jar包：my-spring-app.jar

运行即可：java -jar target/my-spring-app.jar

五月 16, 2015 10:46:52 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [applicationContext.xml]
五月 16, 2015 10:46:53 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.support.GenericXmlApplicationContext@4a5e88f7: startup date [Sat May 16 22:46:53 CST 2015]; root of context hierarchy
五月 16, 2015 10:46:53 下午 org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
INFO: Pre-instantiating singletons in org.springframework.beans.factory.support.DefaultListableBeanFactory@18fd54ec: defining beans [org.springframework.context.annotation.internalConfigurationAnnotationProcessor,org.springframework.context.annotation.internalAutowiredAnnotationProcessor,org.springframework.context.annotation.internalRequiredAnnotationProcessor,org.springframework.context.annotation.internalCommonAnnotationProcessor,userService]; root of factory hierarchy
find liqiu
find liqiu

当然也可以这么运行：java -classpath target/my-spring-app.jar com.exec.Main

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