Map<String, Object> paramMap = request.getParameterMap();
Set<String> keys = paramMap.keySet();
for(String key:keys){
System.out.println(key+":"+Arrays.toString((String[])paramMap.get(key)));
}

/trxdate:[20180713]
trxid:[111879470000030836]
sign:[028786217EE72E2794E2F6BDC0416D16]
acct:[6217000010094452144]
cusorderid:[1531477147738]
termtraceno:[0]
trxstatus:[0000]
appid:[00000156]
trxcode:[VSP301]
cusid:[990581053996001]
outtrxid:[1531477147738]
paytime:[20180713181942]
trxamt:[1000000]/