Java与C交互

/**
* Java与C交互
* @param param 上送信息
* @return 返回信息
*/
public static Map<String, String> infExchange(Object param){
Map<String, String> returnMsg = null;

Socket socket = null;
DataOutputStream outputStream = null;
DataInputStream inputStream = null;

String host = null;
int port = 0;
try{
//读取地址及端口号
host = Global.getConfig("socket.host");
port = Integer.valueOf(Global.getConfig("socket.port"));

//创建socket
socket = new Socket(host, port);
socket.setSoTimeout(20000);//超时时间设置为20s

//对象转化为json
ObjectMapper mapper = new ObjectMapper();
String json = mapper.writeValueAsString(param);

//前加4位长度
String sendMsg = StringUtils.padLeft(String.valueOf(json.getBytes("GBK").length), '0', 4) + json;
System.out.println("上送报文：" + sendMsg);

//上送
outputStream = new DataOutputStream(socket.getOutputStream());
outputStream.write(sendMsg.getBytes("GBK"));
outputStream.flush();

//接收返回
inputStream = new DataInputStream(socket.getInputStream());
byte[] b = new byte[4];
int count = 1;//只读取两次，第一次读取报文长度，第二次读取完整报文
while(inputStream.read(b)!=-1){
if(count==1){
int len = Integer.valueOf(new String(b));
b = new byte[len];
count++;
Thread.sleep(200);
}else{
break;
}
}
String response = new String(b, "GBK");
System.out.println("返回报文：" + response);

//将返回json转化为map格式
if(response!=null && !"".equals(response)){
returnMsg = mapper.readValue(response, Map.class);
}
}catch(Exception e){
e.printStackTrace();
}finally{
//关闭流
try {
inputStream.close();
outputStream.close();
socket.close();
} catch (IOException e) {
e.printStackTrace();
}
}

return returnMsg;
}