查询条件拼接SQL

public static void query() throws ParseException {String jsonStr = "{applyNo:{like:'A001'}, name:{=:'张三'}, amt:{>: 600, oper: 'or', <: 1000}}";JSONObject json = new JSONObject(jsonStr);Iterator<String> iter = json.keys();StringBuffer jpql = new StringBuffer("select * from table");// 放置参数List<Object> params = new ArrayList<Object>();int index = 0;boolean firstFlag = true;while (iter.hasNext()) {// 查询字段String key = iter.next();JSONObject obj = json.getJSONObject(key);if (firstFlag) {firstFlag = false;jpql.append(" where ");} else {jpql.append(" and ");}jpql.append(key).append(" ");Iterator<String> valIter = obj.keys();while (valIter.hasNext()) {// 查询条件String valKey = valIter.next();// 不是操作符，就执行if (!"oper".equals(valKey)) {Object valObj = obj.get(valKey);jpql.append(valKey).append(" ?_").append(index).append(" ");if (valIter.hasNext()) {Object oper = obj.get("oper");jpql.append(" ").append(oper).append(" ");}params.add(valObj);index++;}}}System.out.println(jpql);System.out.println(Arrays.toString(params.toArray()));}