报错信息为：

Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.apache.commons.beanutils.PropertyUtilsBean.invokeMethod(PropertyUtilsBean.java:2155)
	at org.apache.commons.beanutils.PropertyUtilsBean.getSimpleProperty(PropertyUtilsBean.java:1323)
	at org.apache.commons.beanutils.PropertyUtilsBean.getNestedProperty(PropertyUtilsBean.java:762)
	at org.apache.commons.beanutils.PropertyUtilsBean.getProperty(PropertyUtilsBean.java:837)
	at org.apache.commons.beanutils.PropertyUtils.getProperty(PropertyUtils.java:426)
	at net.sf.json.JSONObject.defaultBeanProcessing(JSONObject.java:749)
	... 55 more
Caused by: java.lang.IllegalArgumentException
	at java.sql.Date.getHours(Date.java:187)
	... 65 more

原因：

java.sql.util.Date 类的 getHours 方法已经被弃用，但是 net.sf.json.JSONObject.fromObject(javaObject) 进行 json 序列化的时候仍然调用了这个方法。

这篇博客中描述的很详细：https://segmentfault.com/a/1190000016937108

结局方法：

json-lib 有一个配置类 JsonConfig，通过 JsonConfig 可以注册一个字段处理器，通过实现 JsonValueProcessor 接口，将 Date 格式化后使用。

加入依赖：

		<dependency>
            <groupId>net.sf.json-lib</groupId>
            <artifactId>json-lib</artifactId>
            <version>2.4</version>
            <classifier>jdk15</classifier>
        </dependency>

实现接口：

@Test
public void testJson(){
    Map<String, Object> mp = new ModelMap();
    mp.put("server",server.getAll());
<span class="hljs-type">JsonConfig</span> <span class="hljs-variable">config</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">JsonConfig</span>();
config.registerJsonValueProcessor(java.sql.Date.class, <span class="hljs-keyword">new</span> <span class="hljs-title class_">JsonValueProcessor</span>() {
    <span class="hljs-keyword">private</span> <span class="hljs-type">SimpleDateFormat</span> <span class="hljs-variable">sd</span> <span class="hljs-operator">=</span> <span class="hljs-keyword">new</span> <span class="hljs-title class_">SimpleDateFormat</span>(<span class="hljs-string">"yyyy-MM-dd"</span>);

    <span class="hljs-meta">@Override</span>
    <span class="hljs-keyword">public</span> Object <span class="hljs-title function_">processArrayValue</span><span class="hljs-params">(Object arg0, JsonConfig arg1)</span> {
        <span class="hljs-keyword">return</span> <span class="hljs-literal">null</span>;
    }

    <span class="hljs-meta">@Override</span>
    <span class="hljs-keyword">public</span> Object <span class="hljs-title function_">processObjectValue</span><span class="hljs-params">(String arg0, Object arg1, JsonConfig arg2)</span> {
        <span class="hljs-type">return</span> <span class="hljs-variable">arg1</span> <span class="hljs-operator">=</span>= <span class="hljs-literal">null</span> ? <span class="hljs-string">""</span> : sd.format(arg1);
    }
});

<span class="hljs-type">JSONObject</span> <span class="hljs-variable">jsonObject</span> <span class="hljs-operator">=</span> JSONObject.fromObject(mp);

<span class="hljs-type">String</span> <span class="hljs-variable">msg</span> <span class="hljs-operator">=</span> jsonObject.toString();
System.out.println(msg);

}