java 中sqlite的备份 还原问题!!!
以下是我的代码。。。。
package javaSqlite;
import java.io.*;
public class backupsqlite{
public static void main(String[] args) {
backup();
//load();
}
public static void backup() {
try {
Runtime rt = Runtime.getRuntime();
Process source = rt.exec("e:/sqlite3/sqlite3 new .dump");
InputStream in = source.getInputStream();
InputStreamReader cov = new InputStreamReader(in, "utf8");
//An InputStreamReader is a bridge from byte streams to character streams
String inStr;
StringBuffer sb = new StringBuffer("");
String outStr;
BufferedReader br = new BufferedReader(cov);
while ((inStr = br.readLine()) != null) {
sb.append(inStr + "\r\n");
System.out.println("I " +inStr);
}
outStr = sb.toString();//Returns a string representing the data in this sequence
System.out.println("O " +outStr);
//An OutputStreamWriter is a bridge from character streams to byte streams
FileOutputStream fout = new FileOutputStream(
"e:/sqlite3/studentsqlite.txt");
OutputStreamWriter writer = new OutputStreamWriter(fout, "utf8");
writer.write(outStr);
writer.flush();
in.close();
cov.close();
br.close();
writer.close();
fout.close();
System.out.println("/* Backup finished! */");
} catch (Exception e) {
e.printStackTrace();
System.out.println(e);
}
}
}
得到的TXT文件中只显示:
BEGIN TRANSACTION;
COMMIT;
直接用SQLITE导出则是:
BEGIN TRANSACTION;
CREATE TABLE studentsqlite(
Matrikelnr int(10) primary key,
Name varchar(10),
Fach varchar(10),
Note float,
Datum date,
Zeit timestamp);
INSERT INTO "studentsqlite" VALUES(7041960,'shi','mathe',1.3,'2002-08-09','2008-09-08 09:30:04');
INSERT INTO "studentsqlite" VALUES(7041961,'aaa','mathe',1.3,'2002-08-09','2008-09-08 10:30:04');
INSERT INTO "studentsqlite" VALUES(7041962,'bbb','mathe',1.3,'2002-08-09','2008-09-08 11:30:04');
INSERT INTO "studentsqlite" VALUES(7041963,'ccc','mathe',1.3,'2002-08-09','2008-09-08 12:30:04');
INSERT INTO "studentsqlite" VALUES(7041888,'ddd','mathe',1.3,'2002-08-09','2008-10-08 18:23:34');
COMMIT;
BEGIN TRANSACTION;和COMMIT;之间的内容读不出来,
有可能问题在readline那里。望高手指教!!!谢谢先!
[解决办法]
对于数据库备份根本不需要写程序,直接调用命令就行.
sqlite数据库就是一个文件,如果备份整个数据库,只需要cp命令就行了.
如果只想备份某个表,可使用导入导出命令
导入
命令: .import
sqlite> .import 文件名 表名
注1: 不要忘了开头的点
注2: 这条语句不能用分号结束. 非SQL不需要分号结束.
注3: 需要查看默认的分隔符separator. 必须一致. 如果不一致可能导致sqlite字段分割错误.
查看分隔符使用命令 .show , 如果不一致可直接修改, 比如:
sqlite>.separator ","
将分隔符转为逗号.
举例1:
将文件a.csv中的数据导入表 tab_xx. (a.csv中字段以逗号分割)
sqlite> .separator ","
sqlite> .import a.csv tab_xx
sqlite>
导入结束.
导出
实现方式: 将输出重定向至文件.
命令: .output
sqlite> .output a.txt
然后输入sql语句, 查询出要导的数据. 查询后,数据不会显示在屏幕上,而直接写入文件.
结束后,输入
sqlite> .output stdout
将输出重定向至屏幕.
举例2:
将 tab_xx 中的数据导出到文件a.txt
sqlite> .output a.txt
sqlite> select * from tab_xx;
sqlite> .output stdout
导出完毕.