我正在创建一个具有 CellTable 的网页。我需要为这个表提供来自 hbase 表的数据。
我已经编写了一种从 hbase 表中检索数据并对其进行测试的方法。
但是当我将该方法调用为 GWT 异步 RPC 方法时，rpc 调用成功但它没有返回任何内容。在我的情况下，它返回空列表。警报框显示列表的大小为 0。
以下是相关代码。
请帮忙。
greetingService.getDeviceIDData(new AsyncCallback<List<DeviceDriverBean>>(){
public void onFailure(Throwable caught) {
// Show the RPC error message to the user
System.out.println("RPC Call failed");
Window.alert("Data : RPC call failed");
}
public void onSuccess(List<DeviceDriverBean> result) {
//on success do something
Window.alert("Data : RPC call successful");
//deviceDataList.addAll(result);
Window.alert("Result size: " +result.size());
// Add a text column to show the driver name.
TextColumn<DeviceDriverBean> nameColumn = new TextColumn<DeviceDriverBean>() {
@Override
public String getValue(DeviceDriverBean object) {
Window.alert(object.getName());
return object.getName();
}
};
table.addColumn(nameColumn, "Name");
// Add a text column to show the device id
TextColumn<DeviceDriverBean> deviceidColumn = new TextColumn<DeviceDriverBean>() {
@Override
public String getValue(DeviceDriverBean object) {
return object.getDeviceId();
}
};
table.addColumn(deviceidColumn, "Device ID");
table.setRowCount(result.size(), true);
// more code here to add columns in celltable
// Push the data into the widget.
table.setRowData(0, result);
SimplePager pager = new SimplePager();
pager.setDisplay(table);
VerticalPanel vp = new VerticalPanel();
vp.add(table);
vp.add(pager);
// Add it to the root panel.
RootPanel.get("datagridContainer").add(vp);
}
});
从 hbase 检索数据的代码（服务器端代码）
public List<DeviceDriverBean> getDeviceIDData()
throws IllegalArgumentException {
List<DeviceDriverBean> deviceidList = new ArrayList<DeviceDriverBean>();
// Escape data from the client to avoid cross-site script
// vulnerabilities.
/*
* input = escapeHtml(input); userAgent = escapeHtml(userAgent);
*
* return "Hello, " + input + "!<br><br>I am running " + serverInfo +
* ".<br><br>It looks like you are using:<br>" + userAgent;
*/
try {
Configuration config = HbaseConnectionSingleton.getInstance()
.HbaseConnect();
HTable testTable = new HTable(config, "driver_details");
byte[] family = Bytes.toBytes("details");
Scan scan = new Scan();
int cnt = 0;
ResultScanner rs = testTable.getScanner(scan);
for (Result r = rs.next(); r != null; r = rs.next()) {
DeviceDriverBean deviceDriverBean = new DeviceDriverBean();
byte[] rowid = r.getRow(); // Category, Date, Sentiment
NavigableMap<byte[], byte[]> map = r.getFamilyMap(family);
Iterator<Entry<byte[], byte[]>> itrt = map.entrySet()
.iterator();
deviceDriverBean.setDeviceId(Bytes.toString(rowid));
while (itrt.hasNext()) {
Entry<byte[], byte[]> entry = itrt.next();
//cnt++;
//System.out.println("Count : " + cnt);
byte[] qual = entry.getKey();
byte[] val = entry.getValue();
if (Bytes.toString(qual).equalsIgnoreCase("account_number")) {
deviceDriverBean.setAccountNo(Bytes.toString(val));
} else if (Bytes.toString(qual).equalsIgnoreCase("make")) {
deviceDriverBean.setMake(Bytes.toString(val));
} else if (Bytes.toString(qual).equalsIgnoreCase("model")) {
deviceDriverBean.setModel(Bytes.toString(val));
} else if (Bytes.toString(qual).equalsIgnoreCase("driver_name")) {
deviceDriverBean.setName(Bytes.toString(val));
} else if (Bytes.toString(qual).equalsIgnoreCase("premium")) {
deviceDriverBean.setPremium(Bytes.toString(val));
} else if (Bytes.toString(qual).equalsIgnoreCase("year")) {
deviceDriverBean.setYear(Bytes.toString(val));
} else {
System.out.println("No match found");
}
/*
* System.out.println(Bytes.toString(rowid) + " " +
* Bytes.toString(qual) + " " + Bytes.toString(val));
*/
}
deviceidList.add(deviceDriverBean);
}
}
catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (Exception e) {
// System.out.println("Message: "+e.getMessage());
e.printStackTrace();
}
return deviceidList;
}