将数据转成JSON

前言

前面咱们在使用Strus2的时候，Struts2自带了组件可以让JavaBean对象、集合转成是JSON，不用咱们本身拼接…这是很是方便的。可是，咱们不必定使用Struts2框架来作开发呀。所以，咱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);
    }

}

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总结

把要解析成JSON 的javaBena对象、集合放进下面这段代码便可！

 JSONArray jSONArray = JSONArray.fromObject(map);

不管放进去什么，返回的都是数组

<script type="text/javascript"> $(function () { $('pre.prettyprint code').each(function () { var lines = $(this).text().split('\n').length; var $numbering = $('<ul/>').addClass('pre-numbering').hide(); $(this).addClass('has-numbering').parent().append($numbering); for (i = 1; i <= lines; i++) { $numbering.append($('<li/>').text(i)); }; $numbering.fadeIn(1700); }); }); </script>