java - 如何将 Groovy 列表强制转换为对象？

Question

我正在关注 this关于使用列表和映射作为构造函数的博客文章。

为什么以下列表无法强制反对？

class Test {
    static class TestObject {
        private int a = 1;
        protected int b = 2;
        public int c = 3;
        int d = 4;
        String s = "s";
    }

    static main(args) {
        def obj = [1, 2, 3, 4, 's'] as TestObject
    }
}

我得到这个异常:

Caught: org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object '[1, 2, 3, 4, s]' with class 'java.util.ArrayList' to class 'in.ksharma.Test$TestObject' due to: groovy.lang.GroovyRuntimeException: Could not find matching constructor for: in.ksharma.Test$TestObject(java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.String)
org.codehaus.groovy.runtime.typehandling.GroovyCastException: Cannot cast object '[1, 2, 3, 4, s]' with class 'java.util.ArrayList' to class 'in.ksharma.Test$TestObject' due to: groovy.lang.GroovyRuntimeException: Could not find matching constructor for: in.ksharma.Test$TestObject(java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.Integer, java.lang.String)
    at in.ksharma.Test.main(Test.groovy:22)

Answer 1

你可以使用 map :

class Test {
    static class TestObject {
        private int a = 1;
        protected int b = 2;
        public int c = 3;
        int d = 4;
        String s = "s";
    }

    static main(args) {
        def o = ['a':1,b:'2',c:'3','d':5,s:'s'] as TestObject
        println o.d
    }
}

一会儿会想到列表。

编辑

嗯..我不确定列表是否可行。仅当您添加适当的构造函数时。完整示例:

class Test {
    static class TestObject {
        TestObject() {
        }

        TestObject(a,b,c,d,s) {
            this.a = a
            this.b = b
            this.c = c
            this.d = d
            this.s = s
        }


        private int a = 1;
        protected int b = 2;
        public int c = 3;
        int d = 4;
        String s = "s";
    }

    static main(args) {
        def obj = ['a':1,b:'2',c:'3','d':5,s:'s'] as TestObject
        assert obj.d == 5
        obj = [1, 2, 3, 6, 's'] as TestObject
        assert obj.d == 6
    }
}