freemarker如何通过一个变量取对象的属性值？

Question

public class TestBean { 
    private String selTestBean1; 
    private String selTestBean2; 
    private String selTestBean3;
}

List<String> colList = new ArrayList<String>();
colList.add("selTestBean1");
colList.add("selTestBean2");
colList.add("selTestBean3");

<#if colList?exists && testBean?exists>
   <#list colList as str  >
      <input type="text" id="${str?if_exists}" name="${str?if_exists}" value=""/>
   </#list>
</#if>

colList中的字符串是testBean中的属性名，一一对应，str变量的值即testBean的属性

input标签的value值是testBean对应属性的值，value值要怎么写