UDP通信之后拿到字符串，我要对他进行截取处理！
byte[] inBuf=new byte[1024];
DatagramPacket inPacket=new DatagramPacket(inBuf,inBuf.length);
socket.receive(inPacket);
receiveInfo= new String(inPacket.getData());
我要写一个方法字符串截取
private String stringTopoint(String str,int len){
String ret = "";
StringBuilder sb = new StringBuilder();
for(int i=0;i<len;i++){
ret=sb.substring(3, 6);
}
return ret;
}但是我拿到数据是字节的，我又要对字符串处理，我要怎么调用我写的方法呢？求大神赐教
你可以先把它变成字符String str= new String（inPacket.getData(),inPacket.getLength());然后你就可以 这样调用 toPoint（str，str.length())
你的方法命名有问题应该是toPoint（...),还有你可以不用传入length，java是面向对象编程，你直接用str.length()就可以获取到它的大小了
是不是我截取的程序写的有问题呢？大神求赐教！
把你整个代码发来
可能是别的问题，你Ip写对了吗？端口是否相同
它没问题，receive本身就是个阻塞方法它没接受到数据时它会一直阻塞等待中
/UDP数据接收线程
public class udpReceiveThread extends Thread
{
@Override
public void run()
{
try
{
socket = new DatagramSocket(8081);
listenStatus=true;
while(listenStatus)
{
// byte[] inBuf= new byte[1024];
byte[] inBuf=new byte[1024];
DatagramPacket inPacket=new DatagramPacket(inBuf,inBuf.length);
socket.receive(inPacket);
// String str= new String(inPacket.getData(),inPacket.getLength());
String str = new String (inPacket.getData());
receiveInfo= stringTopoint(str,inPacket.getLength()).trim();
//receiveInfo = stringTopoint(receiveInfo, inPacket.getLength()).trim();
// receiveInfo= bytes2HexString(inBuf,inPacket.getLength());
// receiveInfo = recvHexData(inPacket.getData(), inPacket.getLength());
// receiveInfo=recvHexData(inPacket.getLength()).trim();
Message msg = new Message();
receiveHandler
.sendMessage(msg);
}
} catch (Exception e)
{
e.printStackTrace();
// TODO Auto-generated catch block
}
}
}
//发送按钮单击事件
public void SendButtonClick(View source)
{
new udpSendThread().start();
}
//监听按钮点击事件
public void ListenButtonClick(View source)
{
if(listenStatus==false)
{
stop.setText("停止监听");
new udpReceiveThread().start();
}
else
{
stop.setText("开始监听");
socket.close();
listenStatus=false;
new udpReceiveThread().interrupt();
}
}
private String stringTopoint(String ret,int len){
StringBuilder sb = new StringBuilder();
for(int i=0;i<len;i++){
ret=sb.substring(3, 6);
}
return ret;
}
private String recvHexData(int len)
{
fBuffer = new byte[len];
System.arraycopy(inBuf, 0, fBuffer, 0, len);//复制数组
StringBuilder sb = new StringBuilder(fBuffer.length);
String rHex = "";
for (int i = 0; i < fBuffer.length; i++)
{
rHex = Integer.toHexString(fBuffer[i] & 0xFF);
if (rHex.length() == 1)
rHex = "0" + rHex;
sb.append(rHex.toUpperCase());
}
return sb.toString().trim();
}
/*
public static int bytetopoint(byte[] b,int len){
int ret = 0;
for(int i=0;i<len;i++){
int hex=(b[i]<<3
)|(b[i]<<6);
ret=Integer.valueOf(hex);
}
return ret;
}
*/
// byte[]转16进制字符串
public static String bytes2HexString(byte[] b,int len)
{
String ret = "";
for (int i = 0; i < len; i++)
{
String hex = Integer.toHexString(b[ i ] & 0xFF);
if (hex.length() == 1)
{
hex = '0' + hex;
}
ret += hex.toUpperCase()+" ";
}
return ret;
}
private static byte charToByte(char c)
{
return (byte) "0123456789ABCDEF".indexOf(c);
}
/* //bye[] 转为字符串
public static String bytesToString(byte[] b,int len){
String ret="" ;
for(int i=0;i<len;i++){
ret=b.substring(3, 6)+"";
String hex = Integer.toHexString(b[ i ] & 0xFF);
String hex = String.valueOf(b[i]);//将字节转化为字符串
string hex=b[i].substring(3, 6)+"";
ret+=hex.substring(3, 6)+" ";//截取3-6位
ret += hex.toUpperCase()+" ";
}
return ret;
}*/
//报文判断
//
// ReceiveChar()
private boolean ReceiveChar(char Char,int len)
{ byte[] RBuffer = new byte[len];
System.arraycopy(inBuf,0, RBuffer, 0, len);
if(Char != 'p' && RBuffer.length == 0)
return false;
ScanResult __RxBuffer = null;
// 将字符写入缓冲 //byte[] inbuf=new byte[256]; //
__RxBuffer.writeToParcel((Parcel) inBuf, Char); // 如果收到的字符不是结束符，则退出 if(Char !='!')
{ if(RBuffer.length > 10) //Buffer.clear(); return false; }
// 收到结束符，对报文加以解析处理 // 首先检查报文格式
if((RBuffer[0]=='p')&&(RBuffer[4]=='!'))
if(RBuffer.length != 10) { // __RxBuffer.clear(); return false; }
// 解析应答报文 Object __LPosition; Object __RPosition;
int __LPosition;
int __RPosition;
if(RBuffer[1] == '1') __LPosition = CharToWord(RBuffer, 7);
else if(RBuffer[1] == '2') __RPosition = CharToWord(RBuffer, 7);
}}
return true;}
//RBuffer.substring(3,RBuffer[6]);
// Char=CharToWord(RBuffer[4],6); return true; }
// CharToHex()
Byte CharToHex(Byte Char)
{ if(Char >= '0' && Char <= '9')
return (byte) (Char - '0');
else if(Char >= 'A' && Char <= 'F')
return (byte) (Char - 'A' + 10);
else if(Char >= 'a' && Char <='f')
return (byte) (Char - 'a' + 10);
else return 0; }
//------------------
int CharToWord(byte[] Buffer, int Begin)
{ return (CharToHex(Buffer[Begin]) << 12) | (CharToHex(Buffer[Begin + 1]) << 8) |
(CharToHex(Buffer[Begin + 2]) << 4) | CharToHex(Buffer[Begin + 3]); }
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
你得发送端了，你要先点击监听，再点发送。。。不然就不会接受到数据
receiveInfo= stringTopoint(str,inPacket.getLength()).trim();，现在是这句话有问题
你是先点监听再点的发送吗
private String stringTopoint(String ret,int len){
StringBuilder sb = new StringBuilder();
for(int i=0;i<len;i++){
ret=sb.substring(3, 6);
}
return ret;
}
这有问题sb时StringBuffer你是搞错了吧
你是想sb.append(ret.substring(3,6));吗