JAVA编程中中如何读取TXT文件数据并计算

JAVA中如何读取TXT文件数据并计算,觉得好久评论

import java.io.BufferedReader;import java.io.File;import java.io.FileNotFoundException;import java.io.FileReader;import java.io.IOException;import java.io.PrintWriter;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;public class Testa { public static void main(String[] args)  {  //传入参数为文件目录  test("d:/a.txt"); }  public static void test(String filePath){  BufferedReader br = null;  try {   br = new BufferedReader(new FileReader(filePath));  } catch (FileNotFoundException e) {   e.printStackTrace();   return;  }    String []columnName = {"Id", "Name", "Languages", "Math", "English"}; //列名  int []courseIndexs = {2, 3, 4};          //课程对应的列  int i,j,index;  String line;  List<Map<String, Object>> students = new ArrayList<Map<String, Object>>();  //记录Id和总值,用于排序  List<Map<String, Object>> sortList = new ArrayList<Map<String, Object>>();  try {   br.readLine(); //去掉第一行   while((line = br.readLine()) != null){    index = 0;    String []se = line.split(" ");    Map<String, Object> student = new HashMap<String, Object>();    for(i = 0; i < se.length; i++){     if("".equals(se[i])){      continue;     }     if(index >= columnName.length){      continue;     }     student.put(columnName[index], se[i]);     index++;    }    //计算平均值,总值    double total = 0;    for(j = 0; j < courseIndexs.length; j++){     total += Double.parseDouble((String) student.get(columnName[courseIndexs[j]]));    }    double average = total / courseIndexs.length;    //只取一位小数    average = Math.round(average * 10)/10;    student.put("Total", total);    student.put("Average", average);        Map<String, Object> sort = new HashMap<String, Object>();    sort.put("Id", student.get("Id"));    sort.put("Total", student.get("Total"));    sortList.add(sort);        students.add(student);   }   br.close();      //排序   for(i = 0; i < sortList.size(); i++){    for(j = i + 1; j < sortList.size(); j++){     if((Double)sortList.get(i).get("Total") < (Double)sortList.get(j).get("Total")){      Map<String, Object> temp = sortList.get(i);      sortList.set(i, sortList.get(j));      sortList.set(j, temp);     }    }   }   Map<Object, Integer> sortedId = new HashMap<Object, Integer>();   for(i = 0; i < sortList.size(); i++){    sortedId.put(sortList.get(i).get("Id"), i+1);   }      //设定序号   for(j = 0; j < students.size(); j++){    students.get(j).put("Order", sortedId.get(students.get(j).get("Id")));   }      //输出(写到原文件)   //PrintWriter pw = new PrintWriter(new File(filePath));   //输出(写到其他文件)   PrintWriter pw = new PrintWriter(new File("D:/b.txt"));      pw.println("Id\tName\tLan\tMath\tEnglish\tAverage\tTotal\tSort");   int cIndex;   for(i = 0; i < students.size(); i++){    Map<String, Object> st = students.get(i);    cIndex = 0;    pw.println(st.get(columnName[cIndex++]) + "\t" + st.get(columnName[cIndex++])      + "\t" + st.get(columnName[cIndex++])+ "\t" + st.get(columnName[cIndex++])      + "\t" + st.get(columnName[cIndex++])      + "\t" + st.get("Total")      + "\t" + st.get("Average")      + "\t" + st.get("Order"));   }   pw.flush();   pw.close();  } catch (IOException e) {   e.printStackTrace();  } }}