java中从txt文件读取数据以及写数据到txt文件

package com.baorant;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.InputStreamReader;
import java.util.ArrayList;

public class FileUtil {

    /*
     * 测试用主函数
     */
    public static void main(String[] args) throws Exception {
        // File file = new File("test.txt");//数组写到文件中
        // int[] datas = {1,2,3,4,5};
        //
        // intDataToFileOut(datas, file);

        // 读取csv文件存到txt文件中
        // int[] recordsTotal;
        //
        // File csv = new File("csv//1203.csv"); // CSV文件路径
        // int[] records0 = GetExcelData.returnFinalArray(csv);
        // File csv1 = new File("csv//1204.csv"); // CSV文件路径
        // int[] records1 = GetExcelData.returnFinalArray(csv1);
        // File csv2 = new File("csv//1205.csv"); // CSV文件路径
        // int[] records2 = GetExcelData.returnFinalArray(csv2);
        // File csv3 = new File("csv//1206.csv"); // CSV文件路径
        // int[] records3 = GetExcelData.returnFinalArray(csv3);
        // File csv4 = new File("csv//1207.csv"); // CSV文件路径
        // int[] records4 = GetExcelData.returnFinalArray(csv4);
        // File csv5 = new File("csv//1208.csv"); // CSV文件路径
        // int[] records5 = GetExcelData.returnFinalArray(csv5);
        // File csv6 = new File("csv//1209.csv"); // CSV文件路径
        // int[] records6 = GetExcelData.returnFinalArray(csv6);
        //
        // recordsTotal = combine_two_intdata(records0,records1);
        // recordsTotal = combine_two_intdata(recordsTotal,records2);
        // recordsTotal = combine_two_intdata(recordsTotal,records3);
        // recordsTotal = combine_two_intdata(recordsTotal,records4);
        // recordsTotal = combine_two_intdata(recordsTotal,records5);
        //
        // for(int i = 0; i < recordsTotal.length; i++){
        // System.out.print(recordsTotal[i] + " ");
        // }
        //
        // File file = new File("trainData.txt");//数组写到文件中
        // intDataToFileOut(recordsTotal, file);
        //
        // File file1 = new File("testData.txt");//数组写到文件中
        // intDataToFileOut(records6, file1);

        //读取file中数据存到数组中
        System.out.println("获取训练数据：");
        String pathname1 = "trainData.txt"; // 绝对路径或相对路径都可以，这里是绝对路径，写入文件时演示相对路径
        File file = new File(pathname1); // 要读取以上路径的input。txt文件
        intFileTOData(1729, file);
        //读取file中数据存到数组中
        System.out.println("获取测试数据：");
        String pathname2 = "trainData.txt"; // 绝对路径或相对路径都可以，这里是绝对路径，写入文件时演示相对路径
        File file2 = new File(pathname2); // 要读取以上路径的input。txt文件
        intFileTOData(1729, file2);

    }

    /*
     * 读取txt中数据存到数组中
     */
    public static int[] intFileTOData(int length, File file) throws Exception {
        /* 读入TXT文件 */
        // String pathname = "trainData.txt"; //
        // 绝对路径或相对路径都可以，这里是绝对路径，写入文件时演示相对路径
        // File filename = new File(pathname); // 要读取以上路径的input。txt文件
        InputStreamReader reader = new InputStreamReader(new FileInputStream(file)); // 建立一个输入流对象reader
        BufferedReader br = new BufferedReader(reader); // 建立一个对象，它把文件内容转成计算机能读懂的语言
        String line = "";
        line = br.readLine();
        int[] datas = new int[1729];
        int i = 0;
        while (line != null) {
            line = br.readLine(); // 一次读入一行数据
            System.out.println(line);
            if (null != line) {
                int tem = Integer.valueOf(line.trim());
                datas[i++] = tem;
            }
        }
        for (int j = 0; j < datas.length; j++) {
            System.out.println(datas[j] + " ");
        }
        return datas;
    }

    /*
     * 数组写到txt文件中
     */
    public static void intDataToFileOut(int[] datas, File file) throws Exception {

        FileWriter out = new FileWriter(file);
        for (int i = 0; i < datas.length; i++) {
            String content = datas[i] + "";
            out.write(content + "	");
            out.write("
");
        }
        out.close();
    }

    /*
     * 连接2个整形数组，得到1个整形数组
     */
    public static int[] combine_two_intdata(int a[], int b[]) {

        ArrayList<Integer> alist = new ArrayList<Integer>(a.length + b.length);

        for (int j = 0; j < a.length; j++) {
            alist.add(a[j]);
        }

        for (int k = 0; k < b.length; k++) {
            alist.add(b[k]);
        }

        int c[] = new int[alist.size()];

        for (int i = 0; i < alist.size(); i++) {
            c[i] = alist.get(i);
        }
        return c;
    }
}

数据格式：

trainData.txt:

package com.baorant;
import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.FileWriter;import java.io.InputStreamReader;import java.util.ArrayList;
public class FileUtil {
/* * 测试用主函数 */public static void main(String[] args) throws Exception {// File file = new File("test.txt");//数组写到文件中// int[] datas = {1,2,3,4,5};//// intDataToFileOut(datas, file);
// 读取csv文件存到txt文件中// int[] recordsTotal;//// File csv = new File("csv//1203.csv"); // CSV文件路径// int[] records0 = GetExcelData.returnFinalArray(csv);// File csv1 = new File("csv//1204.csv"); // CSV文件路径// int[] records1 = GetExcelData.returnFinalArray(csv1);// File csv2 = new File("csv//1205.csv"); // CSV文件路径// int[] records2 = GetExcelData.returnFinalArray(csv2);// File csv3 = new File("csv//1206.csv"); // CSV文件路径// int[] records3 = GetExcelData.returnFinalArray(csv3);// File csv4 = new File("csv//1207.csv"); // CSV文件路径// int[] records4 = GetExcelData.returnFinalArray(csv4);// File csv5 = new File("csv//1208.csv"); // CSV文件路径// int[] records5 = GetExcelData.returnFinalArray(csv5);// File csv6 = new File("csv//1209.csv"); // CSV文件路径// int[] records6 = GetExcelData.returnFinalArray(csv6);//// recordsTotal = combine_two_intdata(records0,records1);// recordsTotal = combine_two_intdata(recordsTotal,records2);// recordsTotal = combine_two_intdata(recordsTotal,records3);// recordsTotal = combine_two_intdata(recordsTotal,records4);// recordsTotal = combine_two_intdata(recordsTotal,records5);//// for(int i = 0; i < recordsTotal.length; i++){// System.out.print(recordsTotal[i] + " ");// }//// File file = new File("trainData.txt");//数组写到文件中// intDataToFileOut(recordsTotal, file);//// File file1 = new File("testData.txt");//数组写到文件中// intDataToFileOut(records6, file1);
//读取file中数据存到数组中System.out.println("获取训练数据：");String pathname1 = "trainData.txt"; // 绝对路径或相对路径都可以，这里是绝对路径，写入文件时演示相对路径File file = new File(pathname1); // 要读取以上路径的input。txt文件intFileTOData(1729, file);//读取file中数据存到数组中System.out.println("获取测试数据：");String pathname2 = "trainData.txt"; // 绝对路径或相对路径都可以，这里是绝对路径，写入文件时演示相对路径File file2 = new File(pathname2); // 要读取以上路径的input。txt文件intFileTOData(1729, file2);
}
/* * 读取txt中数据存到数组中 */public static int[] intFileTOData(int length, File file) throws Exception {/* 读入TXT文件 */// String pathname = "trainData.txt"; //// 绝对路径或相对路径都可以，这里是绝对路径，写入文件时演示相对路径// File filename = new File(pathname); // 要读取以上路径的input。txt文件InputStreamReader reader = new InputStreamReader(new FileInputStream(file)); // 建立一个输入流对象readerBufferedReader br = new BufferedReader(reader); // 建立一个对象，它把文件内容转成计算机能读懂的语言String line = "";line = br.readLine();int[] datas = new int[1729];int i = 0;while (line != null) {line = br.readLine(); // 一次读入一行数据System.out.println(line);if (null != line) {int tem = Integer.valueOf(line.trim());datas[i++] = tem;}}for (int j = 0; j < datas.length; j++) {System.out.println(datas[j] + " ");}return datas;}
/* * 数组写到txt文件中 */public static void intDataToFileOut(int[] datas, File file) throws Exception {
FileWriter out = new FileWriter(file);for (int i = 0; i < datas.length; i++) {String content = datas[i] + "";out.write(content + " ");out.write(" ");}out.close();}
/* * 连接2个整形数组，得到1个整形数组 */public static int[] combine_two_intdata(int a[], int b[]) {
ArrayList<Integer> alist = new ArrayList<Integer>(a.length + b.length);
for (int j = 0; j < a.length; j++) {alist.add(a[j]);}
for (int k = 0; k < b.length; k++) {alist.add(b[k]);}
int c[] = new int[alist.size()];
for (int i = 0; i < alist.size(); i++) {c[i] = alist.get(i);}return c;}}

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原文地址：https://www.cnblogs.com/baorantHome/p/9343718.html