JAVA - 表达式解析和评估库
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时间：2020-10-31 07:02:53 来源:igfitidea点击:
JAVA - Expression parsing & evaluating library
提问by duduamar
I'm looking for a JAVA library to parse & evaluate expression. I searched and tried some libraries like Apache's JEXL and Jeval, but they are not exactly what I need.
我正在寻找一个 JAVA 库来解析和评估表达式。我搜索并尝试了一些库，如 Apache 的 JEXL 和 Jeval，但它们并不是我所需要的。
My requirements:
我的要求：
- Support all value types (i.e. int,double,boolean,String, etc.)
- Support all known mathematical & logical operators (+,-,*,<,<=,etc.)
- Support variables (without any special notation - for example in Jeval variable a should be written like #{a} - not good enough for me)
- Support custom functions - with type enforcement and validation
- 支持所有值类型（即int、double、boolean、String等）
- 支持所有已知的数学和逻辑运算符（+、-、*、<、<= 等）
- 支持变量（没有任何特殊符号 - 例如在 Jeval 变量 a 应该写成 #{a} - 对我来说不够好）
- 支持自定义函数 - 具有类型强制和验证
Any recommendations?
有什么建议吗？
回答by lost
回答by Hiery Nomus
回答by Leroy Kegan
You can try mXparser- it supports significant part of your requirements:
您可以尝试mXparser- 它支持您的大部分需求：
- It is based on double, so int is supported, additionally boolean is supportedas true = 1 and false = 0. Unfortunately strings are not supported.
- 它基于双精度型，因此支持 int，此外还支持布尔值，如 true = 1 和 false = 0。不幸的是，不支持字符串。
Boolean example:
布尔示例：
import org.mariuszgromada.math.mxparser.*;
...
...
Constant T = new Constant("T = 1");
Constant F = new Constant("F = 0");
Expression e = new Expression("T && (F || (F && T))", T, F);
System.out.println(e.getExpressionString() + " = " + e.calculate());
Result:
结果：
T && (F || (F && T)) = 0.0
- mXparser has broad support for operators, functions, etc.. Check mXparser math collection. What is nice you can use help functionality inside the library.
- mXparser对运算符、函数等有广泛的支持。检查mXparser 数学集合。您可以使用库中的帮助功能有什么好处。
Example:
例子：
import org.mariuszgromada.math.mxparser.*;
...
...
mXparser.consolePrintHelp("operator");
Result:
结果：
Help content:
2. + <Operator> addition
3. - <Operator> subtraction
4. * <Operator> multiplication
5. / <Operator> division
6. ^ <Operator> exponentiation
7. ! <Operator> factorial
8. # <Operator> modulo function
9. & <Boolean Operator> logical conjunction (AND)
10. && <Boolean Operator> logical conjunction (AND)
11. /\ <Boolean Operator> logical conjunction (AND)
12. ~& <Boolean Operator> NAND - Sheffer stroke
13. ~&& <Boolean Operator> NAND - Sheffer stroke
14. ~/\ <Boolean Operator> NAND - Sheffer stroke
15. | <Boolean Operator> logical disjunction (OR)
16. || <Boolean Operator> logical disjunction (OR)
17. \/ <Boolean Operator> logical disjunction (OR)
18. ~| <Boolean Operator> logical NOR
19. ~|| <Boolean Operator> logical NOR
20. ~\/ <Boolean Operator> logical NOR
21. (+) <Boolean Operator> exclusive or (XOR)
22. --> <Boolean Operator> implication (IMP)
23. <-- <Boolean Operator> converse implication (CIMP)
24. -/> <Boolean Operator> material nonimplication (NIMP)
25. </- <Boolean Operator> converse nonimplication (CNIMP)
26. <-> <Boolean Operator> logical biconditional (EQV)
27. ~ <Boolean Operator> negation
28. ? <Boolean Operator> negation
162. add <Variadic Function> (2.4) Summation operator add(a1,a2,a3,...,an)
168. sum <Calculus Operator> summation operator (SIGMA) sum(i, from, to, f(i,...))
169. prod <Calculus Operator> product operator (PI) prod(i, from, to, f(i,...))
170. int <Calculus Operator> definite integral operator ( int(f(x,...), x, a, b) )
171. der <Calculus Operator> derivative operator ( der(f(x,...), x) )
172. der- <Calculus Operator> left derivative operator ( der-(f(x,...), x) )
173. der+ <Calculus Operator> right derivative operator ( der+(f(x,...), x) )
174. dern <Calculus Operator> n-th derivative operator ( dern(f(x,...), x) )
175. diff <Calculus Operator> forward difference operator
176. difb <Calculus Operator> backward difference operator
177. avg <Calculus Operator> (2.4) Average operator avg(i, from, to, f(i,...))
178. vari <Calculus Operator> (2.4) Bias-corrected sample variance operator vari(i, from, to, f(i,...))
179. stdi <Calculus Operator> (2.4) Bias-corrected sample standard deviation operator stdi(i, from, to, f(i,...))
180. mini <Calculus Operator> (2.4) Minimum value mini(i, from, to, f(i,...))
181. maxi <Calculus Operator> (2.4) Maximum value maxi(i, from, to, f(i,...))
182. solve <Calculus Operator> (4.0) f(x) = 0 equation solving, function root finding: solve( f(x,...), x, a, b )
301. @~ <Bitwise Operator> (4.0) Bitwise unary complement
302. @& <Bitwise Operator> (4.0) Bitwise AND
303. @^ <Bitwise Operator> (4.0) Bitwise exclusive OR
304. @| <Bitwise Operator> (4.0) Bitwise inclusive OR
305. @<< <Bitwise Operator> (4.0) Signed left shift
306. @>> <Bitwise Operator> (4.0) Signed right shift
- User defined variablesand user defined constantsare created without any special form.
- 用户定义变量和用户定义常量的创建没有任何特殊形式。
Example:
例子：
import org.mariuszgromada.math.mxparser.*;
...
...
Argument x = new Argument("x = 10");
Constant y = new Constant("y = 2");
Expression e = new Expression("x/y", x, y);
System.out.println(e.getExpressionString() + " = " + e.calculate());
Result:
结果：
x/y = 5.0
Additionally please check: a) Tutorial - User defined arguments, b) Tutorial - User defined constants.
另外请检查：a)教程 - 用户定义的参数，b)教程 - 用户定义的常量。
- User defined functionsare fully supported.
- 完全支持用户定义的函数。
Example 1 - body defined in run-time:
示例 1 - 在运行时定义的主体：
import org.mariuszgromada.math.mxparser.*;
...
...
Function f = new Function("f(x,y) = x*y");
Expression e = new Expression("20-f(2,5)",f);
System.out.println(e.getExpressionString() + " = " + e.calculate());
Result 1
结果 1
20-f(2,5) = 10.0
Example 2 - body extended via your own implementation:
示例 2 - 通过您自己的实现扩展的主体：
import org.mariuszgromada.math.mxparser.*;
...
...
/*
* Implementing FunctionExtension interface
*/
public class Addition implements FunctionExtension {
double x;
double y;
public Addition() {
x = Double.NaN;
y = Double.NaN;
}
public Addition(double x, double y) {
this.x = x;
this.y = y;
}
public int getParametersNumber() {
return 2;
}
public void setParameterValue(int argumentIndex, double argumentValue) {
if (argumentIndex == 0) x = argumentValue;
if (argumentIndex == 1) y = argumentValue;
}
public double calculate(double... params) {
return x+y;
}
public FunctionExtension clone() {
return new Addition(x, y);
}
}
/*
* Creating extended function
*/
Function f = new Function("f", new Addition());
mXparser.consolePrintln("f.calculate(1,2) = " + f.calculate(1,2) );
/*
* Using extended function in expression
*/
Expression e = new Expression("f(2,3)", f);
System.out.println(e.getExpressionString() + " = " + e.calculate() );
Result 2:
结果 2：
f.calculate(1,2) = 3.0
f(2,3) = 5.0
Additionally it is worth to follow the wholemXparser Tutorial.
此外，值得遵循整个mXparser 教程。
Found recently - in case you would like to try the syntax (and see the advanced use case) you can download the ScalarCalculatorappthat is powered by mXparser.
最近发现 - 如果您想尝试语法（并查看高级用例），您可以下载由 mXparser 提供支持的标量计算器应用程序。
Best regards
最好的祝福
回答by Lukas Eder
Here would be a couple of workaround solutions that you could choose from, if you don't find an actual Java expression evaluation library:
如果您没有找到实际的 Java 表达式评估库，那么您可以从以下几个变通解决方案中进行选择：
- Evaluate your expressions using XPath.
- Pros: XPath knows logical operators, and you can implement variables and custom functions using Xalan's extensions
- Cons: XPath has fewer types than Java
- Evaluate your expressions using JavaScript.
- Pros: Javascript is very flexible and will still be suitable when your requirements tighten. You can implement variables and custom functions using Javascript as well
- Cons: Javascript has fewer types than Java
- Evaluate your expressions using JSP's expression language (e.g. with JUEL)
- 使用 XPath 评估您的表达式。
- 优点：XPath 知道逻辑运算符，您可以使用 Xalan 的扩展来实现变量和自定义函数
- 缺点：XPath 的类型比 Java 少
- 使用 JavaScript 评估您的表达式。
- 优点：Javascript 非常灵活，当您的要求收紧时仍然适用。您也可以使用 Javascript 实现变量和自定义函数
- 缺点：Javascript 的类型比 Java 少
- 使用 JSP 的表达式语言（例如使用JUEL）评估您的表达式
