Java数学表达式计算(Expression Evaluator)

常见的表达式计算lib有：

parsii

JEval

JEPLite

expr

Janino

MathEval

(1)parsii

Java代码

String exp = "2 + (7-5) * 3.14159 * x + sin(0)";

// compile

Scope scope = Scope.create();

Expression parsiiExpr = Parser.parse(exp);

Variable var = scope.getVariable("x");

var.setValue(X_VALUE);

// evaluate

double result = parsiiExpr.evaluate();

System.out.println(result);//-> 2.0

(2)JEval

Java代码

String exp = "2 + (7-5) * 3.14159 * #{x} + sin(0)";

// compile

Evaluator jevalEvaluator = new Evaluator();

jevalEvaluator.setVariables(Collections.singletonMap("x", Double.toString(X_VALUE)));

// evaluate

double result = Double.parseDouble(jevalEvaluator.evaluate(exp));

System.out.println(result);//-> 2.0

(3)JEPLite

Java代码

String exp = "2 + (7-5) * 3.14159 * x + sin(0)";

// compile

JEP jep = new JEP();

jep.addVariable("x", X_VALUE);

jep.parseExpression(exp);

DoubleStack jepStack = new DoubleStack();

// evaluate

double result = jep.getValue(jepStack);

System.out.println(result);//-> 2.0

http://andreas.haufler.info/2013/12/how-to-write-one-of-fastest-expression.html

http://www.transylvania-jug.org/archives/5777

ExprEvalSample.zip (157.5 KB)

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