==========================================
fname="d:\\bankmessagedemo\\"+fname+".txt";
BufferedWriter out = new BufferedWriter(new FileWriter(fname));
/*把业务记录写入文件中*/
IndivInfomod indivinfomod=new IndivInfomod();
if (type.equals("1")) {
back = indivinfomod.oneWriteData(out, strDate); //自动生成
}
else {
back = indivinfomod.oneWriteData(out, sdate); //手动生成
}
=========================================
public int oneWriteData(BufferedWriter out, String sdate) {
System.out.println("dingting---------Start:");
odbcConnection mySybase = new odbcConnection();
Connection conndb = null;
Statement stmt = null;
ResultSet rs=null;
int back = 0; //如果返回0为不成功，如果返回1为成功。
try {
conndb = mySybase.getConnection();
String readStr = "select RFDT,IOMK,CYNO,BRNO,AMCD,OTCD,ACIT,TSAM,PRID,USID,MARK from XKJ where RFDT='" +sdate + "' order by BRNO";
stmt = conndb.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
rs = stmt.executeQuery(readStr);
System.out.println("dingting:Now begin to excute from bankcredit..........");
StringBuffer sb = new StringBuffer(512);
while (rs.next()) {
sb.append("|");
sb.append(rs.getString(1)).append("|");
sb.append(rs.getString(2)).append("|");
sb.append(rs.getString(3)).append("|");
sb.append(rs.getString(4)).append("|");
sb.append(rs.getString(5)).append("|");
sb.append(rs.getString(6)).append("|");
sb.append(rs.getString(7)).append("|");
sb.append(rs.getString(8)).append("|");
sb.append(rs.getString(9)).append("|");
sb.append(rs.getString(9)).append("|");
sb.append(rs.getString(10)).append("|");
sb.append(rs.getString(11)).append("|");
sb.append("\n");
}
if (!sb.equals("")) {
back = 1;
}
System.out.println("dingting:Now end to excute from bankcredit..........");
out.write(sb.toString());
out.flush();
out.close();
}
catch (Exception ex) {
System.out.println(mySybase.getErrorMessage(ex,"Application error,please contact to your Software Designer!").toString());
}
finally {
try {
if(conndb != null){
conndb.close();
rs.close();
}
}
catch (Exception e) {
}
}
return back;
}
===================================
操作：查询数据库，读取数据，插入到文本文件中，但是查询数据量达到100万时，报内存溢出，请大家看看程序都有什么问题
报错信息：Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space
------解决方案--------------------
百万数据非同小可，这样做溢出是在所难免的
建议分批write
------解决方案--------------------
做个类似批量处理的处理
- Java code
while (rs.next()) { sb.append("|"); sb.append(rs.getString(1)).append("|"); sb.append(rs.getString(2)).append("|"); sb.append(rs.getString(3)).append("|"); sb.append(rs.getString(4)).append("|"); sb.append(rs.getString(5)).append("|"); sb.append(rs.getString(6)).append("|"); sb.append(rs.getString(7)).append("|"); sb.append(rs.getString(8)).append("|"); sb.append(rs.getString(9)).append("|"); sb.append(rs.getString(9)).append("|"); sb.append(rs.getString(10)).append("|"); sb.append(rs.getString(11)).append("|"); sb.append("\n"); count ++; if (count % 10000 == 0) { out.write(sb.toString()); sb.delete(0, sb.length()); } }