我有一个邮箱文件,其中包含50多条消息,分隔如下:
From - Jul 7月19日07:11:55 2007
我想在Java中为此构建一个正则表达式,以便一次提取一封邮件,因此我尝试使用扫描程序,使用以下模式作为分隔符:
public boolean ParseData(DataSource data_source) {
boolean is_successful_transfer = false;
String mail_header_regex = "^From\\s";
LinkedList<String> ip_addresses = new LinkedList<String>();
ASNRepository asn_repository = new ASNRepository();
try {
Pattern mail_header_pattern = Pattern.compile(mail_header_regex);
File input_file = data_source.GetInputFile();
//parse out each message from the mailbox
Scanner scanner = new Scanner(input_file);
while(scanner.hasNext(mail_header_pattern)) {
String current_line = scanner.next(mail_header_pattern);
Matcher mail_matcher = mail_header_pattern.matcher(current_line);
//read each mail message and extract the proper "received from" ip address
//to put it in our list of ip's we can add to the database to prepare
//for querying.
while(mail_matcher.find()) {
String message_text = mail_matcher.group();
String ip_address = get_ip_address(message_text);
//empty ip address means the line contains no received from
if(!ip_address.trim().isEmpty())
ip_addresses.add(ip_address);
}
}//next line
//add ip addresses from mailbox to database
is_successful_transfer = asn_repository.AddIPAddresses(ip_addresses);
}
//error reading file--unsuccessful transfer
catch(FileNotFoundException ex) {
is_successful_transfer = false;
}
return is_successful_transfer;
}
这似乎应该可行,但每当我运行它时,程序都会挂起,可能是由于它没有找到模式。这个相同的正则表达式在Perl中使用相同的文件,但在Java中它始终挂在String current_line = scanner.next(mail_header_pattern);
这个正则表达式是正确的还是我正确解析文件?
答案 0 :(得分:1)
通过阅读行,我会倾向于更简单的 ,这样的事情:
while(scanner.hasNextLine()) {
String line = scanner.nextLine();
if (line.matches("^From\\s.*")) {
// it's a new email
} else {
// it's still part of the email body
}
}