将数据转成JSON

￡神魔★判官ぃ 2021-09-17 06:44 481阅读 0赞

# 前言 #

前面我们在使用Strus2的时候，Struts2自带了组件能够让JavaBean对象、集合转成是JSON，不用我们自己拼接…这是非常方便的。但是，我们不一定使用Struts2框架来做开发呀。因此，我们还得**学习使用第三方库来将JavaBean对象、集合转成JSON**

# 导入开发包 #

*  commons-io-2.0.1.jar
 *  commons-lang-2.5.jar
 *  commons-collections-3.1.jar
 *  commons-beanutils-1.7.0.jar
 *  ezmorph-1.0.3.jar
 *  json-lib-2.1-jdk15.jar

# 事例代码 #

package cn.itcast.javaee.js.bean2json;
    
    import net.sf.json.JSONArray;
    
    import java.util.*;
    
    /** * 使用第三方工具，将JavaBean对象/List或Set或Map对象转成JSON * @author AdminTC */
    public class TestBean2Json {
        private static void javabean2json() {
            City city = new City(1,"广州");
            JSONArray jSONArray = JSONArray.fromObject(city);
            String jsonJAVA = jSONArray.toString();
            System.out.println(jsonJAVA);
            //[{
        "id":1,"name":"广州"}]
        }
        private static void list2json() {
            List<City> cityList = new ArrayList<City>();
            cityList.add(new City(1,"广州"));
            cityList.add(new City(2,"珠海"));
            JSONArray jSONArray = JSONArray.fromObject(cityList);
            String jsonJAVA = jSONArray.toString();
            System.out.println(jsonJAVA);
            //[{
        "id":1,"name":"广州"},{
        "id":2,"name":"珠海"}]
        }
        private static void set2json() {
            Set<City> citySet = new LinkedHashSet<City>();
            citySet.add(new City(1,"广州"));
            citySet.add(new City(2,"珠海"));
            JSONArray jSONArray = JSONArray.fromObject(citySet);
            String jsonJAVA = jSONArray.toString();
            System.out.println(jsonJAVA);
            //[{
        "id":1,"name":"广州"},{
        "id":2,"name":"珠海"}]
        }
        private static void javabeanlist2json() {
            List<City> cityList = new ArrayList<City>();
            cityList.add(new City(1,"中山"));
            cityList.add(new City(2,"佛山"));
            Province province = new Province(1,"广东",cityList);
    
            JSONArray jSONArray = JSONArray.fromObject(province);
            String jsonJAVA = jSONArray.toString();
            System.out.println(jsonJAVA);
            /* [ { "id":1, "name":"广东" "cityList":[{"id":1,"name":"中山"},{"id":2,"name":"佛山"}], } ] */
        }
        private static void map2json() {
    
            List<City> cityList = new ArrayList<City>();
            cityList.add(new City(1,"中山"));
            cityList.add(new City(2,"佛山"));
    
            Map<String,Object> map = new LinkedHashMap<String,Object>();
            map.put("total",cityList.size());//表示集合的长度
            map.put("rows",cityList);//rows表示集合
    
            JSONArray jSONArray = JSONArray.fromObject(map);
            String jsonJAVA = jSONArray.toString();
            System.out.println(jsonJAVA);
            //[{
        "total":2,"rows":[{
        "id":1,"name":"中山"},{
        "id":2,"name":"佛山"}]}]
    
            jsonJAVA = jsonJAVA.substring(1,jsonJAVA.length()-1);
            System.out.println(jsonJAVA);
        }
    
    }

--------------------

# 总结 #

**把要解析成JSON 的javaBena对象、集合放进下面这段代码即可！**

JSONArray jSONArray = JSONArray.fromObject(map);

**无论放进去什么，返回的都是数组**