少女装都有哪些品牌?
2024-04-27
2025-07-17 15:44 和牧服饰
1. 简单的手动放置 键值对 到JSONObject,然后在put到JSONArray对象里 List<Article> al = articleMng.find(f); System.out.println(al.size()); HttpServletResponse hsr = ServletActionContext.getResponse(); if(null == al){ return ; } for(Article a : al){ System.out.println(a.getId()+a.getDescription()+a.getTitle()); } JSONArray json = new JSONArray(); for(Article a : al){ JSONObject jo = new JSONObject(); jo.put(id, a.getId()); jo.put(title, a.getTitle()); jo.put(desc, a.getDescription()); json.put(jo); } try { System.out.println(json.toString()); hsr.setCharacterEncoding(UTF-8); hsr.getWriter().write(json.toString()); } catch (IOException e) { e.printStackTrace(); } 复制代码 上述代码JSONArray是引入的org.json.JSONArray包 而用net.sf.json包下JSONArray的静态方法:fromObject(list) 这是网上大多是都是直接用此方法快捷转换JSON,但是对于Hibernate级联操作关联的对象,这个方法就会报错,如果将映射文件中的级联配置去掉就行了。 另外对于list的要求就是其中的元素是字符串或对象,否则JSON不知道你想要的是什么数据。 <many-to-one name=cmsent column=comment_tid class=com.fcms.cms.entity.CmsComment not-null=false cascade=delete> 但是级联操作毕竟还是得存在,否则以后数据冗余、多余。 解决方法就是:JSONArray subMsgs = JSONArray.fromObject(object, config); JsonConfig config = new JsonConfig(); config.setJsonPropertyFilter(new PropertyFilter() { public boolean apply(Object arg0, String arg1, Object arg2) { if (arg1.equals(article) ||arg1.equals(fans)) { return true; } else { return false; } } }); 复制代码 说明:提供了一个过滤作用,如果遇到关联的对象时他会自动过滤掉,不去执行关联关联所关联的对象。这里我贴出我hibernate中的配置关系映射的代码帮助理解: <!-- 配置话题和团体之间的关系 --> <many-to-one name=article class=com.fcms.nubb.article column=article_id/> <!-- 配置主题帖与回复的帖子之间的关系 --> <set name=subMessages table=sub_message inverse=true cascade=all lazy=false order-by=date asc> <key column=theme_id /> <one-to-many class=bbs.po.SubMessage /> </set> 总结: 1. JSONArray subMsgs = JSONArray.fromObject(subMessages, config);其中config是可选的,当出现上面的情况是可以配置config参数,如果没有上面的那种需求就可以直接使用fromObject(obj)方法,它转换出来的就是标准的json对象格式的数据,如下: {[attr, content, ...}, ...]} 2. JSONObject jTmsg = JSONObject.fromObject(themeMessage, config);这是专门用来解析标准的pojo,或者map对象的,pojo对象的格式就不用说了,map的形式是这样的{str, str}。 package com.nubb.bean; import java.io.Serializable; public class Person implements Serializable{ private static final long serialVersionUID = 1L; private String name; private int age; private String address; public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getAddress() { return address; } public void setAddress(String address) { this.address = address; } } package com.nubb.test; import java.io.IOException; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.StandardOpenOption; import java.util.ArrayList; import java.util.List; import com.alibaba.fastjson.JSON; import com.nubb.bean.Person; public class JSONSerializer { private static final String DEFAULT_CHARSET_NAME = UTF-8; public static <T> String serialize(T object) { return JSON.toJSONString(object); } public static <T> T deserialize(String string, Class<T> clz) { return JSON.parseObject(string, clz); } public static <T> T load(Path path, Class<T> clz) throws IOException { return deserialize( new String(Files.readAllBytes(path), DEFAULT_CHARSET_NAME), clz); } public static <T> void save(Path path, T object) throws IOException { if (Files.notExists(path.getParent())) { Files.createDirectories(path.getParent()); } Files.write(path, serialize(object).getBytes(DEFAULT_CHARSET_NAME), StandardOpenOption.WRITE, StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING); } public static void main(String[] args) { Person person1 = new Person(); person1.setAddress(address); person1.setAge(11); person1.setName(amao); Person person2 = new Person(); person2.setAddress(address); person2.setAge(11); person2.setName(amao); List<Person> lp = new ArrayList<Person>(); lp.add(person1); lp.add(person2); System.out.println(serialize(lp)); } } 输出: [{address:address,age:11,name:amao},{address:address,age:11,name:amao}]