java-scripting-engine

问题 How can I determine if a variable exists from within the Groovy code running in the Scripting Engine? The variable was put by ScriptEngine's put method 回答1: In the groovy.lang.Script there is a method public Binding getBinding() . See also groovy.lang.Binding with method public boolean hasVariable(String name) . Thus you can simple check variable existence like if (binding.hasVariable('superVariable')) { // your code here } 回答2: // Example usage: defaultIfInexistent({myVar}, "default") def

问题 How can I determine if a variable exists from within the Groovy code running in the Scripting Engine? The variable was put by ScriptEngine's put method 回答1: In the groovy.lang.Script there is a method public Binding getBinding() . See also groovy.lang.Binding with method public boolean hasVariable(String name) . Thus you can simple check variable existence like if (binding.hasVariable('superVariable')) { // your code here } 回答2: // Example usage: defaultIfInexistent({myVar}, "default") def