Question

我正在尝试使用Mvel java库来评估表达式。表达式是检查列表是否包含给定的字符串，但是在执行程序时我得到ClassCastException。以下是代码段。

感谢任何帮助，谢谢！

import org.mvel2.MVEL;

import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * Created by rakesh on 25-Nov-16.
 */
public class Test {
    public static void main(String[] args) {
        Map<String, Object> evalParams = new HashMap<>();
        List<String> list = Arrays.asList("abc", "xyz", "asd");
        evalParams.put("subType",list);
//        evalParams.put("contentType","Hotfixes");
        System.out.println();
//        System.out.println(MVEL.evalToBoolean("contentType == \"Hotfixes\" && \"abc\" in subType", evalParams));
        System.out.println(MVEL.evalToBoolean("\"abc\" in subType", evalParams));
    }
}

Maven依赖详情：

<dependency>
    <groupId>org.mvel</groupId>
    <artifactId>mvel2</artifactId>
    <version>2.3.1.Final</version>
</dependency>

堆栈跟踪：

Exception in thread "main" [Error: syntax error or incompatable types]
[Near : {... "abc" in subType ....}]
                      ^
[Line: 1, Column: 10]
    at org.mvel2.compiler.AbstractParser.reduce(AbstractParser.java:2617)
    at org.mvel2.compiler.AbstractParser.arithmeticFunctionReduction(AbstractParser.java:2522)
    at org.mvel2.MVELInterpretedRuntime.parseAndExecuteInterpreted(MVELInterpretedRuntime.java:147)
    at org.mvel2.MVELInterpretedRuntime.parse(MVELInterpretedRuntime.java:47)
    at org.mvel2.MVEL.eval(MVEL.java:288)
    at org.mvel2.MVEL.evalToBoolean(MVEL.java:612)
    at org.mvel2.MVEL.evalToBoolean(MVEL.java:657)
    at Test.main(Test.java:19)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)
Caused by: java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Long
    at org.mvel2.compiler.AbstractParser.reduceNumeric(AbstractParser.java:2643)
    at org.mvel2.compiler.AbstractParser.reduce(AbstractParser.java:2613)
    ... 12 more

评估MVEL表达式 - ClassCastException

0 个答案: