java需要从.txt文本里读取特定的字段，并写入另一个.txt

Question

读取之前
读取之后
a,b,c,....e是表示标签，先的是数据，我需要读取特定标签下面的数据，麻烦写个代码，谢谢，我刚学java，超级菜鸟，别嘲笑，现在力求进步，谢谢大佬们，运行成功，就给币。

Answer 1

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class TestAAA {

    public static void main(String[] args) throws Exception {
        File file = new File("C:\\Users\\Administrator\\Desktop\\新建文本文档.txt");
        BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(new File("C:\\Users\\Administrator\\Desktop\\新建文本文档1.txt")),"UTF-8"));
        String[] strs = {"a", "b", "d", "e"};//要读的标签
        int num[] = new int[strs.length];//每个标签的位置
        String[] left = new String[strs.length];
        String[] right = new String[strs.length];
        BufferedInputStream inputStream = new BufferedInputStream(new FileInputStream(file));
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream),5*1024*1024);
        String line = null;
        if((line = reader.readLine()) != null) {
            String[] infoArraay = line.split(" ");
            for (int i = 0; i < strs.length; i++) {
                for (int j = 0; j < infoArraay.length; j++) {
                    int begin = 0;
                    if((begin=infoArraay[j].indexOf(strs[i]))!=-1) {
                        num[i] = j;
                        String leftStr = infoArraay[j].substring(0, begin);;
                        String rightStr = infoArraay[j].substring(begin+strs[i].length()-1, infoArraay[j].length()-1);
                        left[i] = leftStr;
                        right[i] = rightStr;
                        writer.write(infoArraay[j]+" ");
                        break;
                    }
                }
            }
            writer.newLine();
        }
        while((line = reader.readLine()) != null) {//逐行的读
            String[] infoArraay = line.split(" ");
            String str = "";
            for (int i = 0; i < num.length; i++) {
                str += infoArraay[num[i]].replace(left[i], "").replace(right[i], "")+",";
            }
            str = str.substring(0, str.length()-1);
            writer.write(str);
            writer.newLine();
        }
        reader.close();
        writer.close();
    }
}

改了下，你试试
运行前
a b c d .....e.....
a1 b1 c1 d1 .....e1.....
a2 b2 c2 d2 .....e2.....
a3 b3 c3 d3 .....e3.....
a4 b4 c4 d4 .....e4.....
a5 b5 c5 d5 .....e5.....
a6 b6 c6 d6 .....e6.....
a7 b7 c7 d7 .....e7.....
a8 b8 c8 d8 .....e8.....
a9 b9 c9 d9 .....e9.....
运行后
a b d e
a1,b1,d1,e1
a2,b2,d2,e2
a3,b3,d3,e3
a4,b4,d4,e4
a5,b5,d5,e5
a6,b6,d6,e6
a7,b7,d7,e7
a8,b8,d8,e8
a9,b9,d9,e9