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检测类路径下是否存在jar包中的class冲突,通常用于web应用的lib目录下class冲突检查
package liq.utils;
import java.io.File;
import java.util.Arrays;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
/**
* 检测classPath下的类冲突,通常用于web应用的lib目录下jar包中class冲突检测,
* 避免程序运行过程中出现如下的类似异常:
* {@link NoSuchMethodError}、{@link NoSuchMethodException}
* {@link ClassNotFoundException}、{@link NoClassDefFoundError}
*
* @author 0532
*
*/
public class ClassConflictCheck {
private static Map<String, HashSet<String>> classMap = new HashMap<String, HashSet<String>>();
public static void check(String classPath) throws Exception {
File dir = new File(classPath);
File[] jarFiles = dir.listFiles();
for (File jarFile : jarFiles) {
if (jarFile.getName().endsWith(".jar")) {
JarFile jar = new JarFile(jarFile);
Enumeration<JarEntry> enumeration = jar.entries();
while (enumeration.hasMoreElements()) {
JarEntry jarEntry = enumeration.nextElement();
if (jarEntry.getName().endsWith(".class")) {
storeClassAndJarRel(jarEntry.getName(), jar.getName());
}
}
}
}
}
private static void storeClassAndJarRel(String className, String jarName) {
HashSet<String> jarSet = classMap.get(className);
if (jarSet == null) {
jarSet = new HashSet<String>();
}
jarSet.add(jarName.substring(jarName.lastIndexOf("/") + 1));
classMap.put(className, jarSet);
}
public static void main(String[] args) throws Exception {
//args = new String[] { "/Users/soft/tomcat-7.0.54.1/deploy/cloud-mobile-cloudapi-gateway/WEB-INF/lib" };
for (String arg : args) {
check(arg);
}
boolean isConflict = false;
for (Iterator<Map.Entry<String, HashSet<String>>> iterator = classMap.entrySet().iterator(); iterator
.hasNext();) {
Map.Entry<String, HashSet<String>> entry = iterator.next();
HashSet<String> jarSet = entry.getValue();
if (jarSet.size() > 1) {
if (!isConflict) {
isConflict = true;
}
List<String> jarList = Arrays.asList(jarSet.toArray(new String[] {}));
System.out.println("Class conflict!!! the class :" + entry.getKey()
+ " has been duplicate inclusioned in the jars : " + jarList);
}
}
if(!isConflict) {
System.out.println("oh,good! there are no class conflict in the jars");
}
}
}
@0532

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0532 commented Dec 2, 2015

用于检测多个Jar包冲突的class

当一个项目使用的jar包较多时,代码经常在运行的时候抛出异常:java.lang.NoSuchMethodException,java.lang.ClassNotFoundException,基本是存在多个jar包包含相同的class类文件导致的,运行期引用的class由于版本没对上导致没有该方法等

该小工具可以帮助你检测出classpath下,通常是项目的lib目录下是否存在类冲突,且告诉你冲突的jar包,方便定位处理。

使用说明,示例:

cd liq/util

javac ClassConflictCheck.java

java ClassConflictCheck xxx/WEB-INF/lib

如果没有任何类冲突,则输出: "oh,good! there are no class conflict in the jars"

否则则有类似如下的冲突输出 (两处冲突了):

Class conflict!!! the class :org/aspectj/weaver/tools/MatchingContext.class has been duplicate inclusioned in the jars : [aspectjweaver-1.6.6.jar, eclipse.aspectj__aspectjweaver-1.5.2a.jar-0.0.0.jar, aspectjtools-1.6.2.jar, aspectjweaver-1.6.2.jar]

Class conflict!!! the class :org/apache/batik/css/engine/value/css2/FontSizeAdjustManager.class has been duplicate inclusioned in the jars : [xml.xmlgraphics-1.7.jar, xml.xmlgraphics__batik-css-1.7.jar-1.7.jar]

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