Question

我想将此示例文件中的某个字符串替换为空值（空字符串）。我用了＃34; \＆＃34;逃避任何会使我的代码工作的东西。我只是想取代＆＃34;终端：＆＃34; UNKNOWN＆＃34; ＆＃34;在此示例文件

中找到

示例文件：

SESSIONID: "19670" ENTRYID: "1" STATEMENT: "1" USERID: "%USERNAME%" USERHOST: "%SRCHOSTNAME%" ACTION: "100" RETURNCODE: "0"
SESSIONID: "19670" ENTRYID: "435" STATEMENT: "20" USERID: "%USERNAME%" USERHOST: "%SRCHOSTNAME%" TERMINAL: "UNKNOWN" ACTION: "3" RETURNCODE: "0" 
SESSIONID: "19670" ENTRYID: "1" STATEMENT: "1" USERID: "%USERNAME%" USERHOST: "%SRCHOSTNAME%" ACTION: "101" RETURNCODE: "0

预期产出：

SESSIONID: "19670" ENTRYID: "1" STATEMENT: "1" USERID: "%USERNAME%" USERHOST: "%SRCHOSTNAME%" ACTION: "100" RETURNCODE: "0"
SESSIONID: "19670" ENTRYID: "435" STATEMENT: "20" USERID: "%USERNAME%" USERHOST: "%SRCHOSTNAME%" ACTION: "3" RETURNCODE: "0" 
SESSIONID: "19670" ENTRYID: "1" STATEMENT: "1" USERID: "%USERNAME%" USERHOST: "%SRCHOSTNAME%" ACTION: "101" RETURNCODE: "0

我的代码：

public static void main(String[] args) throws FileNotFoundException {
    Scanner scan = new Scanner(new File("oracle.log"));
    ArrayList<String> list = new ArrayList<String>();
    while (scan.hasNext()) {
        list.add(scan.next());
    }
    scan.close();

    try {
        //initiates a new File type file
        File file = new File("oracle.log");
        //initiates a new buffereed reader "reader"
        BufferedReader reader = new BufferedReader(new FileReader(file));
        //initialize 2 strings for comparison
        String line = "", oldtext = "";
        while ((line = reader.readLine()) != null) {
            oldtext += line + "\r\n";
        }
        reader.close();

        oldtext = oldtext.replaceAll("%TERMINAL: \"UNKNOWN\"", "");
        FileWriter writer = new FileWriter("new_oracle.log");

        // the entire file is contained within the String 'oldtext'
        writer.write(oldtext);
        writer.close();
    } catch (IOException ioe) {
        ioe.printStackTrace();
    }

}

输出：相同的示例文件没有任何更改

Answer 1

（根据我的评论）正则表达式中的%字符与文字＆＃39;％＆＃39;匹配。符号。我不确定你在那里尝试做什么，但请尝试删除它。

我知道在某些情况下%用于匹配任何内容，在这种情况下，您可以在正则表达式中使用.*，但这会删除行中的所有内容，直到匹配结束。

TERMINAL: \"UNKNOWN\"

我在regex101上测试了它并且工作正常（此工具不需要转义引号，但它们适用于java）https://regex101.com/r/eB2yW9/1

Answer 2

regexp中有一个不必要的符号。只需改变你的

oldtext = oldtext.replaceAll("%TERMINAL: \"UNKNOWN\"", "");

到

oldtext = oldtext.replaceAll("\\s*TERMINAL: \"UNKNOWN\"","");

使用附加的\ s *，删除TERMINAL之前的所有空格：＆＃34; UNKNOWN＆＃34;

如何使用带有null值的replaceAll（）方法替换整个字符串？

2 个答案: