java - 您可以使用 OGNL 访问私有(private)变量吗？

Question

有没有使用 OGNL访问未作为 bean 属性公开的私有(private)变量(即没有 get/set 方法对)？我想将 OGNL 用作单元测试中使用的更快、更清晰的反射方法。

这是我的代码:

@Test
public void shouldSetup() throws OgnlException{
    class A{
        private Object b = "foo";
        private Object c = "bar";
        public Object getB(){ return b; }
    }
    A a = new A();

    System.out.println( "This'll work..." );
    Ognl.getValue( "b", a );

    System.out.println( "...and this'll fail..." );
    Ognl.getValue( "c", a );

    System.out.println( "...and we'll never get here." );
}

Answer 1

其实你可以。您需要在 OgnlContext 中设置 MemberAccess 以允许访问非公共(public)字段，并使用 getValue(ExpressionAccessor expression, OgnlContext context, Object root) 方法来检索值。

@Test
public void shouldSetup() throws OgnlException {
    class A {
        private Object b = "foo";
        private Object c = "bar";
        public Object getB() { return b; }
    }
    A a = new A();

    // set DefaultMemberAccess with allowed access into the context
    OgnlContext context = new OgnlContext();
    context.setMemberAccess(new DefaultMemberAccess(true));

    System.out.println( "This'll work..." );
    // use context in getValue method
    Ognl.getValue( "b", context, a );

    System.out.println( "...and this'll work..." );
    // use context in getValue method
    Ognl.getValue( "c", context, a );

    System.out.println( "...and we'll get here." );
}