JavaMe连载(7)-数据永久存储 - JAVA

try {
this.openDataBase();
info.deleteRecord(id);
this.closeDataBase();
} catch (RecordStoreException ex) {}
}

7 删除所有记录

[html] public void db_deleteAllRecord(){
try {
RecordStore.deleteRecordStore(RECORDSTORE_NAME);
} catch (RecordStoreException ex) {}
}

public void db_deleteAllRecord(){
try {
RecordStore.deleteRecordStore(RECORDSTORE_NAME);
} catch (RecordStoreException ex) {}
}

8 如何使用？

(1) 新建对象

[html] private UserDataRecord userRecord;
private UserDataRecord userRecord;

[html] userRecord = new UserDataRecord();
userRecord = new UserDataRecord();

(2) 添加记录

[html] UserDataItem userItem = new UserDataItem(1,(username+","+passwd).getBytes());
userRecord.db_addRecord(userItem);
UserDataItem userItem = new UserDataItem(1,(username+","+passwd).getBytes());
userRecord.db_addRecord(userItem);

(3) 查看记录

[html] userRecord.db_getRecord(1);
userRecord.db_getRecord(1);
*1为记录id，在添加记录步骤中，id为1。

(4) 更新记录

[html]

UserDataItem userItem = new UserDataItem(1,(username+","+passwd).getBytes()); 
 userRecord.db_updateRecord(userItem); 
 UserDataItem userItem = new UserDataItem(1,(username+","+passwd).getBytes());
 userRecord.db_updateRecord(userItem);
   
 (5) 综合实例 
 [html] userRecord.db_deleteAllRecord(); 
 if(userRecord.db_getRecord(1)==null) 
 { 
     UserDataItem userItem = new UserDataItem(1,(username+","+passwd).getBytes()); 
     userRecord.db_addRecord(userItem); 
     userItem = null; 
 } 
 userRecord.db_deleteAllRecord();
 if(userRecord.db_getRecord(1)==null)
 {
  UserDataItem userItem = new UserDataItem(1,(username+","+passwd).getBytes());
  userRecord.db_addRecord(userItem);
  userItem = null;
 }
 *在添加记录前，要检测当前记录ID是否被使用过，否则“增”操作会失败。如果不指定数值，默认情况下，id会递增1。所以在多次调用时，而又只需要一条记录的情况下，调用了userRecord.db_deleteAllRecord(); 
   
 *将UserDataRecord.java中的UserDataItem改为Object对象，稍作修改，可作为一个通用的数据库，有兴趣的朋友可以试一试。 
   摘自 tandesir的专栏

JavaMe连载(7)-数据永久存储 (三)