JSONValueProcessor日期转化问题

最新推荐文章于 2024-05-23 11:08:56 发布

lethezf

最新推荐文章于 2024-05-23 11:08:56 发布

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分类专栏： java 文章标签： JSON lib

本文链接：https://blog.youkuaiyun.com/qq_35850107/article/details/85088174

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本文详细解析了在使用JSONLib进行Java对象与JSON互转时遇到的日期格式化问题，探讨了错误原因并提供了两种解决方案：一是通过JsonValueProcessor自定义日期格式；二是修改json转换器的日期类型。

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问题来源：

在使用json lib时候遇到了一个奇葩的问题，有一个请求时会报错，报的是日期转换错误。感觉这个是个坑，所以在此记录一下。

最终解决方案：由于查询返回的是List<Map>类型，指定返回结果的时候，用的是java.Util.Map。而数据库中时间的格式是date类型，在mybatis映射的时候，由于用的是map，没有指定resultMap的映射类型。结果传入的日期，使用json转化器转换的时候，传入的日期是java.sql.Date类型（但是json转换器指定的是Date类型的）。需要经过一层包装即可，或者修改注入的json转换器的日期类型为java.sql.Date类型，并对此做相应的实现。

两个大的作用：

①将Java对象转成json格式的字符串或反之

②将Java对象转换成xml格式的文档或反之

常见用途：数值格式化和日期格式化。

使用对象：JsonConfig，JsonValueProcessor。

maven引入：

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

gradle引入：

compile group: 'net.sf.json-lib', name: 'json-lib', version: '2.4'

错误重现
{"time2":"2018-12-31","mp":{"num":200,"time":"2018-12-19"},"num":11,"time":"2018-12-19"} ------------------------------------ Exception in thread "main" net.sf.json.JSONException: java.lang.reflect.InvocationTargetException at net.sf.json.JSONObject.defaultBeanProcessing(JSONObject.java:818) at net.sf.json.JSONObject._fromBean(JSONObject.java:699) at net.sf.json.JSONObject.fromObject(JSONObject.java:172) at net.sf.json.AbstractJSON._processValue(AbstractJSON.java:274) at net.sf.json.JSONObject._processValue(JSONObject.java:2655) at net.sf.json.JSONObject.processValue(JSONObject.java:2721) at net.sf.json.JSONObject.setInternal(JSONObject.java:2736) at net.sf.json.JSONObject.setValue(JSONObject.java:1424) at net.sf.json.JSONObject._fromMap(JSONObject.java:1168) at net.sf.json.JSONObject.fromObject(JSONObject.java:163) at com.lethez.JsonLibTest.main(JsonLibTest.java:39) 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) ... 10 more Caused by: java.lang.IllegalArgumentException at java.sql.Date.getHours(Date.java:187) ... 20 more Process finished with exit code 1

测试代码
package com.lethez; import net.sf.json.JSONObject; import net.sf.json.JsonConfig; import net.sf.json.processors.JsonValueProcessor; import java.text.SimpleDateFormat; import java.util.Date; import java.util.HashMap; import java.util.Locale; import java.util.Map; /** * author: lethez * describe: * date: 2018/12/19 - 9:21 */ public class JsonLibTest { public static void main(String[] args) { Map map = new HashMap(); map.put("time",new Date()); map.put("time2",new Date(new Date().getTime()+1000000000)); map.put("num",11); Map map2 = new HashMap(); map2.put("time",new Date()); map2.put("num",200); map.put("mp",map2); JsonConfig config = new JsonConfig(); config.registerJsonValueProcessor(Date.class, new CustomerJsonValueProcessor("yyyy-MM-dd")); JSONObject jo = JSONObject.fromObject(map,config); System.out.println(jo); System.out.println("------------------------------------"); Map map3 = new HashMap(); //map3.put("time",new java.sql.Date(100000)); map3.put("time",new Date((new java.sql.Date(100000)).getTime())); JsonConfig config2 = new JsonConfig(); config2.registerJsonValueProcessor(Date.class, new CustomerJsonValueProcessor2("yyyy-MM-dd")); JSONObject jo2 = JSONObject.fromObject(map3,config); System.out.println(jo2); } static class CustomerJsonValueProcessor implements JsonValueProcessor{ private String pattern; public Object processArrayValue(Object o, JsonConfig jsonConfig) { return process(o); } @Override public Object processObjectValue(String s, Object o, JsonConfig jsonConfig) { return process(o); } public CustomerJsonValueProcessor() { super(); } public CustomerJsonValueProcessor(String format) { this.pattern = format; } private Object process(Object val){ if(null!=val && val instanceof Date){ SimpleDateFormat sdf = new SimpleDateFormat(this.pattern, Locale.CHINESE); return sdf.format(val); } return val==null?"":val.toString(); } } static class CustomerJsonValueProcessor2 implements JsonValueProcessor{ private String pattern ; public CustomerJsonValueProcessor2() { super(); } public CustomerJsonValueProcessor2(String format) { this.pattern = format; } @Override public Object processArrayValue(Object o, JsonConfig jsonConfig) { return process(o); } @Override public Object processObjectValue(String s, Object o, JsonConfig jsonConfig) { return process(o); } private Object process(Object val){ if(null!=val && val instanceof Date){ SimpleDateFormat sdf = new SimpleDateFormat(this.pattern,Locale.CHINESE); return sdf.format(val); } return val==null?"":val.toString(); } } }

package com.lethez;

import net.sf.json.JSONObject;
import net.sf.json.JsonConfig;
import net.sf.json.processors.JsonValueProcessor;

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

/**
 * author: lethez
 * describe:
 * date: 2018/12/19 - 9:21
 */
public class JsonLibTest {
    
    public static void main(String[] args) {
        Map map = new HashMap();
        map.put("time",new Date());
        map.put("time2",new Date(new Date().getTime()+1000000000));
        map.put("num",11);
        Map map2 = new HashMap();
        map2.put("time",new Date());
        map2.put("num",200);
        map.put("mp",map2);
        JsonConfig config = new JsonConfig();
        config.registerJsonValueProcessor(Date.class, new CustomerJsonValueProcessor("yyyy-MM-dd"));
        JSONObject jo = JSONObject.fromObject(map,config);
        System.out.println(jo);

        System.out.println("------------------------------------");
        Map map3 = new HashMap();
        //map3.put("time",new java.sql.Date(100000));
        map3.put("time",new Date((new java.sql.Date(100000)).getTime()));
        JsonConfig config2 = new JsonConfig();
        config2.registerJsonValueProcessor(Date.class, 
        new CustomerJsonValueProcessor2("yyyy-MM-dd"));
        JSONObject jo2 = JSONObject.fromObject(map3,config);
        System.out.println(jo2);

    }
    
    
      static class CustomerJsonValueProcessor implements JsonValueProcessor{
        
          private String pattern;
          
         public Object processArrayValue(Object o, JsonConfig jsonConfig) {
             return process(o);
         }

         @Override
         public Object processObjectValue(String s, Object o, JsonConfig jsonConfig) {
             return process(o);
         }
         
          public CustomerJsonValueProcessor() {
              super();
          }

          public CustomerJsonValueProcessor(String format) {
              this.pattern = format;
          }

          private  Object process(Object val){
              if(null!=val && val instanceof  Date){
                  SimpleDateFormat sdf =
        new SimpleDateFormat(this.pattern, Locale.CHINESE);
                  return sdf.format(val);
              }
                  return val==null?"":val.toString();
          }

      }

    static class CustomerJsonValueProcessor2 implements JsonValueProcessor{
        
        private String pattern ;

        public CustomerJsonValueProcessor2() {
            super();
        }

        public CustomerJsonValueProcessor2(String format) {
            this.pattern = format;
        }
        
        @Override
        public Object processArrayValue(Object o, JsonConfig jsonConfig) {
            return process(o);
        }

        @Override
        public Object processObjectValue(String s, Object o, JsonConfig jsonConfig) {
            return process(o);
        }


        private  Object process(Object val){
            if(null!=val && val instanceof  Date){
                SimpleDateFormat sdf = new SimpleDateFormat(this.pattern,Locale.CHINESE);
                return sdf.format(val);
            }
                return val==null?"":val.toString();
        }

    }
    
}