开源java文件读取_Java读取文本文件的简单应用

应用情景&＃xff1a;

读取SQL文件&＃xff0c;获取ID&＃xff0c;对先前插入数据库的记录进行删除。

SQL文件大概如下&＃xff1a;

insert into CAR_PAYORDERS (DDBH, MAILL, WDBH, SCRQ, DJZT, DKFS, JYZT, JYRQ, SJRR, SJDH, SJDZ, HZZT, HZRQ, ZFZT, WLDH, YZBM)

values (&＃39;0076d1432f304429a30bdb4e4cf2927c&＃39;, &＃39;sfc-1&＃39;, &＃39;Y001&＃39;, to_date(&＃39;23-12-2015 15:22:10&＃39;, &＃39;dd-mm-yyyy hh24:mi:ss&＃39;), null, 2, null, to_date(&＃39;23-12-2015 17:53:13&＃39;, &＃39;dd-mm-yyyy hh24:mi:ss&＃39;), &＃39;秦飘人&＃39;, &＃39;15015584995&＃39;, null, null, null, 1, null, null);

insert into CAR_PAYORDERS_DETAIL (JFBH, DDBH, CXDM, CPHM, JFNF, SLBH, ZFCG, JFJE, ZFRQ, DJRQ, WLDH, DYTT, ZNJ)

values (&＃39;Y3N441&＃39;, &＃39;0076d1432f304429a30bdb4e4cf2927c&＃39;, &＃39;06&＃39;, &＃39;粤A·Y3N44蓝&＃39;, &＃39;2015&＃39;, &＃39;15015584995&＃39;, 1, 980, to_date(&＃39;23-12-2015 17:53:13&＃39;, &＃39;dd-mm-yyyy hh24:mi:ss&＃39;), to_date(&＃39;23-12-2015 14:22:10&＃39;, &＃39;dd-mm-yyyy hh24:mi:ss&＃39;), null, null, 0);

--........

目标就是获取DDBH对应值&＃xff1a;

代码如下&＃xff1a;

public static void main(String[] args){

Pattern p &＃61; Pattern.compile("[a-z0-9]{32}");

Set set &＃61; new HashSet<>();

try{

BufferedReader br &＃61; new BufferedReader(new FileReader(new File(".\\4.carPayorderdetail.sql")));//构造一个BufferedReader类来读取文件

String s &＃61; null;

while((s &＃61; br.readLine()) !&＃61; null){//使用readLine方法&＃xff0c;一次读一行

Matcher m &＃61; p.matcher(s);

while(m.find()){

set.add(m.group());

}

}

br.close();

for(String str : set){

System.out.println("delete from CAR_PAYORDERS_DETAIL t where t.ddbh&＃61;&＃39;"&＃43;str&＃43;"&＃39;;");

System.out.println("delete from CAR_PAYORDERS t where t.ddbh&＃61;&＃39;"&＃43;str&＃43;"&＃39;;");

}

}catch(Exception e){

e.printStackTrace();

}

}

然后&＃xff0c;在命令行窗口编译、执行

javac Main.java

java Main > deleteOrders.sql