文档：Jep说明文档_jep,javajep-Java文档类资源-CSDN下载

测试代码：

        <!-- jep java表达式分析器 --><dependency><groupId>com.singularsys</groupId><artifactId>jep</artifactId><version>3.5</version><classifier>trial</classifier></dependency>

import com.singularsys.jep.PostfixMathCommandI;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;/*** @author lihai* Create Date: 2021-11-20*/
@Data
@NoArgsConstructor
@AllArgsConstructor
public class JepFunctionPo {private String name;private PostfixMathCommandI function;
}

import cn.hutool.core.util.NumberUtil;
import cn.hutool.core.util.ObjectUtil;
import com.qms.ipqc.common.po.JepFunctionPo;
import com.quality.common.exception.DangerException;
import com.quality.common.exception.GeneralException;
import com.singularsys.jep.Jep;
import com.singularsys.jep.JepException;
import com.singularsys.jep.Variable;
import com.singularsys.jep.VariableTable;
import com.singularsys.jep.bigdecimal.BigDecComponents;
import com.singularsys.jep.functions.*;import java.math.BigDecimal;
import java.math.MathContext;
import java.util.*;
import java.util.List;
import java.util.stream.Collectors;/*** @author lihai* Create Date: 2021-11-20*/
public class JepAnalysisUtil {public static List<JepFunctionPo> getDefaultJepFunctionPoList() {return Arrays.asList(
//                new JepFunctionPo("round", new Round()),
//                new JepFunctionPo("rint", new RInt()),
//                new JepFunctionPo("floor", new Floor()),
//                new JepFunctionPo("ceil", new Ceil()),
//                new JepFunctionPo("abs", new Abs()),new JepFunctionPo("sqrt", new SquareRoot()),new JepFunctionPo("SQRT", new SquareRoot()));}public static Jep newJep(List<JepFunctionPo> functions) {Jep jep = new Jep(new BigDecComponents(MathContext.DECIMAL128));if (ObjectUtil.isNotEmpty(functions)) {functions.forEach(function -> jep.addFunction(function.getName(), function.getFunction()));}return jep;}public static Jep parse(String expression) {Jep jep = newJep(getDefaultJepFunctionPoList());try {jep.parse(expression);return jep;} catch (Exception e) {throw new DangerException("JEP解析表达式失败：" + expression + "，请检查表达式是否合法！");}}public static BigDecimal analysis(String expression, Map<String, Object> variables) {Jep jep = parse(expression);try {if (ObjectUtil.isNotEmpty(variables)) {variables.forEach((k, v) -> {try {jep.addVariable(k, NumberUtil.parseNumber(v.toString()));} catch (JepException e) {throw new DangerException("JEP赋值异常：" + e.getMessage());}});}return new BigDecimal(jep.evaluate().toString());} catch (JepException e) {throw new GeneralException("JEP计算异常：" + e.getMessage());}}public static Set<String> getVariables(String expression) {Jep jep = parse(expression);try {final VariableTable variableTable = jep.getVariableTable();final List<Variable> variables = new ArrayList<>(variableTable.getVariables());return variables.stream().filter(var -> var.getValue() == null).map(Variable::getName).collect(Collectors.toSet());} catch (Exception e) {throw new DangerException("获取JEP变量失败：" + expression);}}public static void checkExpressionVariables(String expression, Set<String> variables) {final Set<String> expressionVariables = getVariables(expression);for (String var : expressionVariables) {if (!variables.contains(var)) {throw new DangerException(String.format("表达式：%s 缺少变量：%s", expression, var));}}}}

测试方法：

    @Testvoid jepAnalysis() {String expression = "sqrt(a-b+c*d/e)";Map<String, Object> params = new HashMap<String, Object>() {{put("a", 5);put("b", 1);put("c", 3);put("d", 2);put("e", 2);}};final BigDecimal analysis = JepAnalysisUtil.analysis(expression, params);System.out.println("计算结果：" + analysis);}