Question

import com.google.gson.Gson;

public class Beanutil {
    public static void main(String args[]) {
        Map<String, Object> yourMap = new HashMap<String, Object>();
        yourMap.put("name", "Joan");
        yourMap.put("age", "309");
        Map<String, Object> secondMap = new HashMap<String, Object>();
        secondMap.put("name", "k");
        secondMap.put("age", "39");
        yourMap.put("bean",secondMap);

        YourBean bean = null;
        try {
            bean= new YourBean();
            try{
            BeanUtils.populate(bean, yourMap);
            }catch(Exception e){
                e.printStackTrace();
            }
            System.out.println(new Gson().toJson(bean));
        } catch (Throwable e) {
            e.getMessage();
        }
    }

}

bean类如下：

public class YourBean {

    String          name    = null;
    int             age     = 0;
    public Bean2    bean;

    //getter & setters
}

public class Bean2 {

        String          name    = null;
        int             age     = 0;


        //getter and setters
    }

获得例外

java.lang.IllegalArgumentException：无法调用 bean类'class上的com.org.nlp.test.YourBean.setBean com.org.nlp.test.YourBean' - 参数类型不匹配 - 有对象类型“java.util.HashMap”但预期签名 “com.org.nlp.test.Bean2”at org.apache.commons.beanutils.PropertyUtilsBean.invokeMethod（PropertyUtilsBean.java:2195）在 org.apache.commons.beanutils.PropertyUtilsBean.setSimpleProperty（PropertyUtilsBean.java:2108）在 org.apache.commons.beanutils.PropertyUtilsBean.setNestedProperty（PropertyUtilsBean.java:1914）在 org.apache.commons.beanutils.PropertyUtilsBean.setProperty（PropertyUtilsBean.java:2021）在 org.apache.commons.beanutils.BeanUtilsBean.setProperty（BeanUtilsBean.java:1018）在 org.apache.commons.beanutils.BeanUtilsBean.populate（BeanUtilsBean.java:823）在 org.apache.commons.beanutils.BeanUtils.populate（BeanUtils.java:431）在 com.org.nlp.test.Beanutil.main（Beanutil.java:24）引起：java.lang.IllegalArgumentException：参数类型不匹配 at sun.reflect.NativeMethodAccessorImpl.invoke0（Native Method）at sun.reflect.NativeMethodAccessorImpl.invoke（NativeMethodAccessorImpl.java:62）在 sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）在java.lang.reflect.Method.invoke（Method.java:498）at org.apache.commons.beanutils.PropertyUtilsBean.invokeMethod（PropertyUtilsBean.java:2127） ... 7更多{“name”：“Joan”，“age”：309}

我很喜欢

{name=Joan, age=309, bean={name=k, age=39}}

请帮我解决这个问题并建议我，如果他们有更好的方法

提前致谢

Answer 1

根据错误消息，您似乎需要首先填充内部Bean2：

BeanUtils.populate(bean2, secondMap);

将填充的bean添加到地图：

yourMap.put("bean",bean2);

然后最后填充bean：

BeanUtils.populate(bean, yourMap);

这样，yourMap包含填充的Bean2成员，并且不需要执行嵌套填充。

Answer 2

Actualy我需要这样，我们可以使用jackson-databind

final ObjectMapper mapper = new ObjectMapper(); 

bean = mapper.convertValue(yourMap, YourBean.class);

将键值转换为POJO

2 个答案: