输出一个对象的所有属性的值,可以不用反射机制，用JSON处理更方便

            String r = "";  
            ObjectMapper mapper = new ObjectMapper();  
            r = mapper.writeValueAsString(credential);  
            System.out.println(r);
            

import com.fasterxml.jackson.databind.ObjectMapper;

jackson-databind.2.2.3.jar

或者：

import  org.codehaus.jackson.map.ObjectMapper

jackson-mapper-asl-1.9.2.jar