许多MIDP应用程序需要简单的存储配置信息，对此，简单封装一个RMSHandler，实现一条记录的读写：
package com.crackj2ee.midp.rms;
import Java.io.*;
import javax.microedition.rms.*;
public final class RMSHandler {
private static final String RECORD_STORE_NAME = "RmsDaTa";
public static boolean loadUniqueRecord(Persistentable p) {
byte[] data = loadUniqueRecord();
if(data==null)
return false;
DataInputStream input = null;
try {
input = new DataInputStream(new ByteArrayInputStream(data));
p.load(input);
return true;
}
catch(IOException ioe) {
return false;
}
finally {
try {
input.close();
}
catch (Exception e) {}
}
}
public static boolean saveUniqueRecord(Persistentable p) {
DataOutputStream output = null;
try {
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
output = new DataOutputStream(bytes);
p.save(output);
return saveUniqueRecord(bytes.toByteArray());
}
catch(IOException ioe) {
return false;
}
finally {
if(output!=null)
try {
output.close();
}
catch (Exception e) {}
}
}
private static byte[] loadUniqueRecord() {
RecordStore rs = null;
RecordEnumeration re = null;
try {
rs = RecordStore.openRecordStore(RECORD_STORE_NAME, true);
if(rs.getNumRecords()==0)
return null;
re = rs.enumerateRecords(null, null, false);
if(re.hasNextElement())
return re.nextRecord();
return null;
}
catch(RecordStoreException rse) {
return null;
}
finally {
if(re!=null) {
re.destroy();
}
if(rs!=null) {
try {
rs.closeRecordStore();
}
catch (Exception e) {}
}
}
}
private static boolean saveUniqueRecord(byte[] data) {
RecordStore rs = null;
RecordEnumeration re = null;
try {
rs = RecordStore.openRecordStore(RECORD_STORE_NAME, true);
re = rs.enumerateRecords(null, null, false);
if(re.hasNextElement()) {
rs.setRecord(re.nextRecordId(), data, 0, data.length);
}
else {
rs.addRecord(data, 0, data.length);
}
return true;
}
catch(RecordStoreException rse) {
return false;
}
finally {
if(re!=null) {
re.destroy();
}
if(rs!=null) {
try {
rs.closeRecordStore();
}
catch (Exception e) {}
}
}
}
}
需要持久化的类实现一个Persistentable接口：
package com.crackj2ee.midp.rms;
import java.io.*;
public interface Persistentable {
void save(DataOutputStream output) throws IOException;
void load(DataInputStream input) throws IOException;
}
读写数据时，按照顺序依次读写即可，例如：
class MyForm extends Form implements Persistentable {
private int score;
private String username;
public MyForm() {
super("Test");
load(this);
}
public void save(DataOutputStream output) throws IOException {
output.writeInt(score);
output.writeUTF8(username);
}
public void load(DataInputStream input) throws IOException {
score = input.readInt();
username = input.readUTF8();
}
}
（出处：http://www.knowsky.com）
