无法创建JexlEngine对象
我写了以下课程：
import org.apache.commons.jexl2.*; public class NelderMead { // контсанты private static int M = 3; private static double E = 0.005; private static double A = 1.000; private static double B = 0.500; private static double Y = 2.000; // переменные private JexlEngine jexl = new JexlEngine(); private Expression func; private String funcString = ""; private MapContext[] iterations; public NelderMead(){ this.jexl = new JexlEngine(); } public NelderMead(String funcString){ this.jexl = new JexlEngine(); this.setFunc(funcString); } public void setFunc(String funcString){ this.funcString = funcString; this.func = this.jexl.createExpression(funcString); } public double funcEval(MapContext args){ return (Double) this.func.evaluate(args); } public boolean checkCriterian(){ return true; } } 但是我创建了这个类的对象我有一个愚蠢的错误：
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory at org.apache.commons.jexl2.JexlEngine$UberspectHolder.(JexlEngine.java:121) at org.apache.commons.jexl2.JexlEngine.getUberspect(JexlEngine.java:205) at org.apache.commons.jexl2.JexlEngine.(JexlEngine.java:182) at org.apache.commons.jexl2.JexlEngine.(JexlEngine.java:170) at NelderMead.(NelderMead.java:22) at Test.main(Test.java:10) Caused by: java.lang.ClassNotFoundException: org.apache.commons.logging.LogFactory at java.net.URLClassLoader$1.run(URLClassLoader.java:202) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:306) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:247) ... 6 more
在构造函数的第一行（当创建JexlEngine的对象时）：
public NelderMead(String funcString){ this.jexl = new JexlEngine(); this.setFunc(funcString); }
你能帮帮我 – 为什么这段代码会导致错误？
PS我使用.jar文件来使用这个lib。
您需要在运行时在类路径中使用commons-logging jar