【1】、第一步，继承Jfinal的基类Json;

import com.alibaba.fastjson.JSON; import com.alibaba.fastjson.serializer.SerializerFeature; import com.jfinal.json.Json; public class MyJson extends Json{ public static String toJsonStr(Object object) { return JSON.toJSONString(object, SerializerFeature.WriteNullListAsEmpty, SerializerFeature.WriteNullStringAsEmpty, SerializerFeature.WriteNullBooleanAsFalse, SerializerFeature.WriteNullNumberAsZero, SerializerFeature.WriteDateUseDateFormat, SerializerFeature.WriteMapNullValue); } @Override public String toJson(Object object) { return JSON.toJSONString(object, SerializerFeature.WriteNullListAsEmpty, SerializerFeature.WriteNullStringAsEmpty, SerializerFeature.WriteNullBooleanAsFalse, SerializerFeature.WriteNullNumberAsZero, SerializerFeature.WriteDateUseDateFormat, SerializerFeature.WriteMapNullValue); } @Override public <T> T parse(String jsonString, Class<T> type) { return JSON.parseObject(jsonString, type); } }

【2】第二步，在Jfinal类里配置一下

public class MyConfig extends JFinalConfig { /**  * 配置常量  */ public void configConstant(Constants me) { me.setJsonFactory(new IJsonFactory() {         public Json getJson() { return new MyJson();}}); } }

搞定了。