java对象转json示例

package com.jun.json; import java.lang.reflect.Field; import java.lang.reflect.Type; import java.util.ArrayList; import java.util.List; import com.jun.modle.ListModel; import com.jun.modle.Model; /** * * @ClassName: ModleToJson * @Description: 把一个对象转成Json格式的数据 * @author hujun * @date 2012-1-25 上午09:26:37 * @version V1.0 */ public class ModleToJson { /** * * @author hujun @date 2013-1-25 上午09:32:51 * @Title: main * @Description: 测试生成的json数据 * @param @param args * @return void 返回类型 * @throws */ public static void main(String[] args) { /** 生成json对象中的toString String model = "com.jun.modle.Model"; String jsonStr = ""; try { jsonStr = toStringJson(model); } catch (Exception e) { e.printStackTrace(); } System.out.println(jsonStr); **/ //测试对象数据 Model m = new Model(); List<ListModel> list = new ArrayList<ListModel>(); ListModel lm = new ListModel(); lm.setTr("sdf"); lm.setTr1("sdf3"); lm.setTr2("sdf23"); ListModel lm1 = new ListModel(); lm1.setTr("sdf"); lm1.setTr1("sdf3"); lm1.setTr2("sdf23"); list.add(lm); list.add(lm1); m.setList(list); m.setTr("sdf"); m.setTr1("sdf"); m.setTr2("sdf"); System.out.println(m.toString()); } /** * * @author hujun @date 2013-1-25 上午09:36:43 * @Title: toStringJson * @Description: 生成model中的toString方法 * @param @param className * @param @return * @param @throws Exception * @return String 返回类型 * @throws */ public static String toStringJson(String className) throws Exception { if (className == null || className.equals("")) { return null; } String space8 = " "; String str = "@Override" + "\r\n"; str += "public String toJson() {" + "\r\n"; str += space8 + "StringBuffer sb = new StringBuffer();" + "\r\n"; str += space8 + "sb.append(\"{\");" + "\r\n"; Class<?> cls = Class.forName(className); Field[] fields = cls.getFields(); for (int i = 0; i < fields.length; i++) { Field field = fields[i]; Type type = field.getType();// .getGenericType(); // 后边的值的两边去掉双引号 if (type.toString().equals("interface java.util.Map") || type.toString().equals("interface java.util.List") || type.toString().equals("class [Ljava.lang.String;") || type.toString().equals( "class org.json.simple.JSONObject")) { str += space8 + "if (null != " + field.getName() + ") {" + "\r\n"; str += space8 + space8 + "sb.append(\"\\\"" + field.getName() + "\\\"\").append(\":\").append(" + field.getName() + ");" + "\r\n"; if (i + 1 != fields.length) { str += space8 + space8 + "sb.append(\",\");" + "\r\n"; } str += space8 + "}" + "\r\n"; } else {// 新增字段如果为空则""，否则"null"在页面中上显示null是不对的 str += space8 + "sb.append(\"\\\"" + field.getName() + "\\\"\").append(\":\").append(\"\\\"\"+((" + field.getName() + " != null)?" + field.getName() + ":\"\")+\"\\\"\");" + "\r\n"; if (i + 1 != fields.length) { str += space8 + "sb.append(\",\");" + "\r\n"; } } } str += space8 + "sb.append(\"}\");" + "\r\n"; str += space8 + "String jsonStr = sb.toString();" + "\r\n"; str += space8 + "if (jsonStr != null && jsonStr.lastIndexOf(\",}\") != -1) {" + "\r\n"; str += space8 + space8 + "jsonStr = jsonStr.substring(0, jsonStr.length()-2)+\"}\";" + "\r\n"; str += space8 + "}" + "\r\n"; str += space8 + "return jsonStr;" + "\r\n"; str += "}" + "\r\n"; return str; } }