用第三方工具类，将JavaBean、List、Map<String,Object>转成JSON文本

导入第三方jar包：

》commons-beanutils-1.7.0.jar

》commons-collections-3.1.jar

》commons-lang-2.5.jar

》commons-logging-1.1.1.jar

》ezmorph-1.0.3.jar

》json-lib-2.1-jdk15.jar

（1）JavaBean->JSON

》JSONArray jsonArray = JSONArray.fromObject(city);

》String jsonJAVA = jsonArray.toString();

（2）List<JavaBean>->JSON

》JSONArray jsonArray = JSONArray.fromObject(cityList);

》String jsonJAVA = jsonArray.toString();

（3）List<String>->JSON

》JSONArray jsonArray = JSONArray.fromObject(stringList);

》String jsonJAVA = jsonArray.toString();

（4）Map<String,Object>->JSON【重点】

package loaderman.bean2json;
 
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
 
import net.sf.json.JSONArray;
 
import org.junit.Test;
 
/**
 * 演示用第三方工具类，将JavaBean、List、Map<String,Object>转成JSON文本
 **/
public class TestJson {
    @Test
    public void javabean2json() {
        User user = new User(1, "哈哈", 123, "男");
        JSONArray jsonArray = JSONArray.fromObject(user);
        String jsonJAVA = jsonArray.toString();
        System.out.println(jsonJAVA);
        //[{"id":1,"name":"哈哈","sal":7000}]
    }
 
    @Test
    public void list2json() {
        List<User> userList = new ArrayList<User>();
        userList.add(new User(1, "恩和", 123, "男"));
        userList.add(new User(2, "恩和老婆", 123, "男"));
        userList.add(new User(3, "恩和小孩", 24, "男"));
        JSONArray jsonArray = JSONArray.fromObject(userList);
        String jsonJAVA = jsonArray.toString();
        System.out.println(jsonJAVA);
        //[{"id":1,"name":"恩和","sal":7000},{"id":2,"name":"福老婆","sal":8000},{"id":3,"name":"恩和","sal":20000}]
    }
 
    @Test
    public void map2json() {
        List<User> userList = new ArrayList<User>();
        userList.add(new User(1, "张三", 7000, "男"));
        userList.add(new User(2, "张三老婆", 8000, "女"));
        userList.add(new User(3, "张三小孩", 20000, "男"));
        userList.add(new User(4, "张三小孩的小孩", 40000, "男"));
 
        Map<String, Object> map = new HashMap<String, Object>();
        //total表示集合的长度
        map.put("total", userList.size());
        //rows表示集合内容
        map.put("rows", userList);
 
        JSONArray jsonArray = JSONArray.fromObject(map);
        String jsonJAVA = jsonArray.toString();
        System.out.println(jsonJAVA);
 
        jsonJAVA = jsonJAVA.substring(1, jsonJAVA.length() - 1);
 
        System.out.println(jsonJAVA);
    }
}