我在我的 RIM Blackberry 应用程序中执行 HttpConnection。我正在使用无线网络连接。在执行 HttpConnection 时，有时它会返回数据，有时它会给出
java.io.IOException 收音机已关闭
和
java.io.IOException 内存不足
错误。我真的不明白到底是什么问题。我在这里发布我的代码片段：
public static String getRemoteData(String url) throws ConnectionNotFoundException{
StringBuffer stringBuff=new StringBuffer();
try {
HttpConnection fconImg = (HttpConnection) Connector.open(url+ NetworkUtils.getConnectionString());
InputStream input = fconImg.openInputStream();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int k = 0;
while ((k = input.read()) != -1) {
baos.write(k);
}
byte[] byteArray = baos.toByteArray();
String s = new String(byteArray);
stringBuff.append(s.trim());
return stringBuff.toString();
} catch (Exception e) {
stringBuff.append("Exception : "+e.toString());
return stringBuff.toString();
}
}
下面是我的 NetworkUtils 类。
import net.rim.device.api.servicebook.ServiceBook;
import net.rim.device.api.servicebook.ServiceRecord;
import net.rim.device.api.system.CoverageInfo;
import net.rim.device.api.system.DeviceInfo;
import net.rim.device.api.system.RadioInfo;
import net.rim.device.api.system.WLANInfo;
public class NetworkUtils {
private static final String COVERAGE_CARRIER = "Carrier full Coverage";
private static final String COVERAGE_MDS = "BES coverage";
private static final String COVERAGE_NONE = "No coverage";
private static final String NOT_SUPPORTED_WAF = "Not supported by the device";
public static String logM;
/**
* Access the net.rim.device.api.system.DeviceInfo class in order to
* understand if the running system is a simulator or a real device.
* @return true if the current application is running on a Blackberry
* simulator, false otherwise
*/
public static boolean isSimulator() {
return DeviceInfo.isSimulator();
}
/**
* Give the information about the presence o a wifi bearer on the device
* @return true if the wifi communication interface bearer is supported by
* the device, false otherwise
*/
protected static boolean isWifiAvailable() {
// Log.info("Checking WIFI Availability");
boolean isWifiEnabled;
if (RadioInfo.areWAFsSupported(RadioInfo.WAF_WLAN)) {
// Log.info("WIFI Supported");
isWifiEnabled = true;
} else {
// Log.info("WIFI NOT Supported");
isWifiEnabled = false;
}
return isWifiEnabled;
}
/**
* Give information about the presence of active wifi connections.
* @return true if the device is connected to a wifi network with its wifi
* bearer, false otherwise
*/
protected static boolean isWifiActive() {
int active = RadioInfo.getActiveWAFs();
int wifi = RadioInfo.WAF_WLAN;
return active >= wifi;
}
protected static boolean isWapGprsDataBearerOffline() {
return RadioInfo.getState()==RadioInfo.STATE_OFF ||
RadioInfo.getSignalLevel() == RadioInfo.LEVEL_NO_COVERAGE;
}
public static String getNetworkCoverageReport() {
StringBuffer sb = new StringBuffer();
sb.append("\n*********************************************************");
sb.append("\nWireless Access Families:");
sb.append("\n3GPP: " + getNetworkCoverage(RadioInfo.WAF_3GPP));
sb.append("\nCDMA: " + getNetworkCoverage(RadioInfo.WAF_CDMA));
sb.append("\nWLAN: " + getNetworkCoverage(RadioInfo.WAF_WLAN));
sb.append("\nCDMA: " + getNetworkCoverage(RadioInfo.NETWORK_CDMA));
sb.append("\nBands:");
sb.append("\nCDMA_800: " + getNetworkCoverage(RadioInfo.BAND_CDMA_800));
sb.append("\nCDMA_1900: " + getNetworkCoverage(RadioInfo.BAND_CDMA_1900));
sb.append("\nNetworks:");
sb.append("\n802_11: " + getNetworkCoverage(RadioInfo.NETWORK_802_11));
sb.append("\nGPRS: " + getNetworkCoverage(RadioInfo.NETWORK_GPRS));
sb.append("\nNetwork services:");
sb.append("\nVOICE: " + getNetworkCoverage(RadioInfo.NETWORK_SERVICE_VOICE));
sb.append("\nUMTS: " + getNetworkCoverage(RadioInfo.NETWORK_SERVICE_UMTS));
sb.append("\nEDGE: " + getNetworkCoverage(RadioInfo.NETWORK_SERVICE_EDGE));
sb.append("\n*********************************************************");
return sb.toString();
}
private static String getNetworkCoverage(int networkType) {
if (RadioInfo.areWAFsSupported(networkType)) {
int status = CoverageInfo.getCoverageStatus(networkType, false);
switch (status) {
// case CoverageInfo.COVERAGE_DIRECT: //TODO if we switch back to < 4.5 we must use CARRIER
// return COVERAGE_CARRIER;//not support less ver of 4.5
case CoverageInfo.COVERAGE_MDS:
return COVERAGE_MDS;
case CoverageInfo.COVERAGE_NONE:
return COVERAGE_NONE;
default:
break;
}
}
return NOT_SUPPORTED_WAF;
}
public static boolean isDataConnectionAvailable() {
boolean ret = (isWifiAvailable()&&isWifiActive())||!isWapGprsDataBearerOffline();
return ret;
}
/**
* Determines what connection type to use and returns the necessary string to use it.
* @return A string with the connection info
*/
public static String getSubURL()
{
// This code is based on the connection code developed by Mike Nelson of AccelGolf.
// http://blog.accelgolf.com/2009/05/22/blackberry-cross-carrier-and-cross-network-http-connection
String connectionString = null;
// Simulator behavior is controlled by the USE_MDS_IN_SIMULATOR variable.
if(DeviceInfo.isSimulator())
{
logMessage("Device is a simulator and USE_MDS_IN_SIMULATOR is false");
connectionString = ";deviceside=true";
}
// Wifi is the preferred transmission method
else if(WLANInfo.getWLANState() == WLANInfo.WLAN_STATE_CONNECTED)
{
logMessage("Device is connected via Wifi.");
connectionString = ";interface=wifi";
}else{
String uid = null;
ServiceBook sb = ServiceBook.getSB();
ServiceRecord[] records = sb.findRecordsByCid("WPTCP");
for (int i = 0; i < records.length; i++) {
if (records[i].isValid() && !records[i].isDisabled()) {
if (records[i].getUid() != null &&
records[i].getUid().length() != 0) {
if ((records[i].getCid().toLowerCase().indexOf("wptcp") != -1) &&
(records[i].getUid().toLowerCase().indexOf("wifi") == -1) &&
(records[i].getUid().toLowerCase().indexOf("mms") == -1) ) {
uid = records[i].getUid();
break;
}
}
}
}
if (uid != null) {
// WAP2 Connection
connectionString = ";ConnectionUID="+uid;
} else {
connectionString = ";deviceside=true";
}
}
return connectionString + ";ConnectionTimeout=60000";
}
/**
* Looks through the phone's service book for a carrier provided BIBS network
* @return The uid used to connect to that network.
*/
private static String getCarrierBIBSUid()
{
ServiceRecord[] records = ServiceBook.getSB().getRecords();
int currentRecord;
for(currentRecord = 0; currentRecord < records.length; currentRecord++)
{
if(records[currentRecord].getCid().toLowerCase().equals("ippp"))
{
if(records[currentRecord].getName().toLowerCase().indexOf("bibs") >= 0)
{
return records[currentRecord].getUid();
}
}
}
return null;
}
public static void logMessage(String str)
{
logM=str;
}
public synchronized static String getConnectionString() {
String connectionString = null;
// Simulator behaviour is controlled by the USE_MDS_IN_SIMULATOR variable.
if (DeviceInfo.isSimulator()) {
connectionString = ";deviceside=true";
}
// Wifi is the preferred transmission method
else if (WLANInfo.getWLANState() == WLANInfo.WLAN_STATE_CONNECTED) {
connectionString = ";interface=wifi";
}
// Is the carrier network the only way to connect?
else if ((CoverageInfo.getCoverageStatus() & CoverageInfo.COVERAGE_DIRECT) == CoverageInfo.COVERAGE_DIRECT) {
String carrierUid = getCarrierBIBSUid();
if (carrierUid == null) {
// Has carrier coverage, but not BIBS. So use the carrier's TCP network
connectionString = ";deviceside=true";
} else {
// otherwise, use the Uid to construct a valid carrier BIBS request
connectionString = ";deviceside=false;connectionUID="+carrierUid + ";ConnectionType=mds-public";
}
}
// Check for an MDS connection instead (BlackBerry Enterprise Server)
else if ((CoverageInfo.getCoverageStatus() & CoverageInfo.COVERAGE_MDS) == CoverageInfo.COVERAGE_MDS) {
connectionString = ";deviceside=false";
}
// If there is no connection available abort to avoid hassling the user
// unnecssarily.
else if (CoverageInfo.getCoverageStatus() == CoverageInfo.COVERAGE_NONE) {
connectionString = "none";
}
// In theory, all bases are covered by now so this shouldn't be reachable.But hey, just in case ...
else {
connectionString = ";deviceside=true";
}
return connectionString;
}
}
首先十分感谢....