转http://blog.sina.com.cn/s/blog_5f1fe33f0100jibg.html
JSON 即 JavaScript Object Natation,它是一种轻量级的数据交换格式,非常适合于服务器与 JavaScript 的交互。本文主要讲解下java和JSON之间的转换,特别是解决互相转换遇到日期问题的情况。
一、需要相关的jar包:json-lib-xxx.jar
ezmorph-xxx.jar
commons-httpclient-xxx.jar
commons-lang-xxx.jar
commons-logging-xxx.jar
commons-collections-xxx.jar
上面的包可以从下面的连接下载:
http://commons.apache.org/index.html
http://json-lib.sourceforge.net
http://ezmorph.sourceforge.net
二、java-》JSON
1.List-》JSON
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List<String> list = new ArrayList<String>();
list.add("apple");
list.add("orange");
JSONArray jarr = JSONArray.fromObject(list);
System.out.println("list->json:" + jarr.toString());
打印结果:list->json:["apple","orange"]
2.Map-》JSON
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Map<String, Object> map = new HashMap<String, Object>();
map.put("name", "Michael");
map.put("baby", new String[] { "Lucy", "Lily" });
map.put("age", 30);
JSONObject jo = JSONObject.fromObject(map);
System.out.println("map->json:" + jo.toString());
打印结果:map->json:{"age":30,"name":"Michael","baby":["Lucy","Lily"]}
3.bean->JSON
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JsonBean bean = new JsonBean();
bean.setName("NewBaby");
bean.setAge(1);
bean.setBorn(new Date());
jo = JSONObject.fromObject(bean);
System.out.println("bean->json:" + jo.toString());
打印结果:bean->json:{"age":1,"born":{"date":10,"day":3,"hours":14,"minutes":14,"month":2,"seconds":1,"time":1268201641228,"timezoneOffset":-480,"year":110},"name":"NewBaby"}
这时你会发现它把bean对象里的util.Date这个类型的所有属性一一转换出来。在实际运用过程中,大多数情况下我们希望能转化为yyyy-MM-dd这种格式,下面就讲一讲如何实现:
首先要写一个新的类JsonDateValueProcessor如下:
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public class JsonDateValueProcessor implements JsonValueProcessor {
private String datePattern = "yyyy-MM-dd";
public JsonDateValueProcessor() {
super();
}
public JsonDateValueProcessor(String format) {
super();
this.datePattern = format;
}
public Object processArrayValue(Object value, JsonConfig jsonConfig) {
return process(value);
}
public Object processObjectValue(String key, Object value,
JsonConfig jsonConfig) {
return process(value);
}
private Object process(Object value) {
try {
if (value instanceof Date) {
SimpleDateFormat sdf = new SimpleDateFormat(datePattern,
Locale.UK);
return sdf.format((Date) value);
}
return value == null ? "" : value.toString();
} catch (Exception e) {