Java按一行一行进行文件的读取或写入

客官°小女子只卖身不卖艺 2023-10-09 20:14 41阅读 0赞

import org.junit.jupiter.api.Test;
    
    import java.io.*;
    import java.util.Arrays;
    
    public class FileTest {
    
        /**
         * 一行一行读取文件，适合字符读取，若读取中文字符时会出现乱码
         *
         * 流的关闭顺序：先打开的后关，后打开的先关，
         *       否则有可能出现java.io.IOException: Stream closed异常
         *
         * @throws IOException
         */
        @Test
        public void readFile01() throws IOException {
            FileReader fr=new FileReader("D:\\desktop\\pmp.txt");
            BufferedReader br=new BufferedReader(fr);
            String line="";
            String[] arrs=null;
            while ((line=br.readLine())!=null) {
                arrs=line.split(",");
    //            System.out.println(arrs[0] + " : " + arrs[1] + " : " + arrs[2]);
                System.out.println(Arrays.asList(arrs).toString());
            }
            br.close();
            fr.close();
        }
    
        /**
         * 一行一行读取文件，解决读取中文字符时出现乱码
         *
         * 流的关闭顺序：先打开的后关，后打开的先关，
         *       否则有可能出现java.io.IOException: Stream closed异常
         *
         * @throws IOException
         */
        @Test
        public void readFile02() throws IOException {
            FileInputStream fis=new FileInputStream("E:/phsftp/evdokey/evdokey_201103221556.txt");
            InputStreamReader isr=new InputStreamReader(fis, "UTF-8");
            BufferedReader br = new BufferedReader(isr);
            //简写如下
            //BufferedReader br = new BufferedReader(new InputStreamReader(
            //        new FileInputStream("E:/phsftp/evdokey/evdokey_201103221556.txt"), "UTF-8"));
            String line="";
            String[] arrs=null;
            while ((line=br.readLine())!=null) {
                arrs=line.split(",");
                System.out.println(arrs[0] + " : " + arrs[1] + " : " + arrs[2]);
            }
            br.close();
            isr.close();
            fis.close();
        }
    
        /**
         * 一行一行写入文件，适合字符写入，若写入中文字符时会出现乱码
         *
         * 流的关闭顺序：先打开的后关，后打开的先关，
         *       否则有可能出现java.io.IOException: Stream closed异常
         *
         * @throws IOException
         */
        @Test
        public void writeFile01() throws IOException {
            String[] arrs={
                    "zhangsan,23,FuJian",
                    "lisi,30,ShangHai",
                    "wangwu,43,BeiJing",
                    "laolin,21,ChongQing",
                    "ximenqing,67,GuiZhou"
            };
            FileWriter fw=new FileWriter(new File("E:/phsftp/evdokey/evdokey_201103221556.txt"));
            //写入中文字符时会出现乱码
            BufferedWriter  bw=new BufferedWriter(fw);
            //BufferedWriter  bw=new BufferedWriter(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(new File("E:/phsftp/evdokey/evdokey_201103221556.txt")), "UTF-8")));
    
            for(String arr:arrs){
                bw.write(arr+"\t\n");
            }
            bw.close();
            fw.close();
        }
    
        /**
         * 一行一行写入文件，解决写入中文字符时出现乱码
         *
         * 流的关闭顺序：先打开的后关，后打开的先关，
         *       否则有可能出现java.io.IOException: Stream closed异常
         *
         * @throws IOException
         */
        @Test
        public void writeFile02() throws IOException {
            String[] arrs={
                    "zhangsan,23,福建",
                    "lisi,30,上海",
                    "wangwu,43,北京",
                    "laolin,21,重庆",
                    "ximenqing,67,贵州"
            };
            //写入中文字符时解决中文乱码问题
            FileOutputStream fos=new FileOutputStream(new File("E:/phsftp/evdokey/evdokey_201103221556.txt"));
            OutputStreamWriter osw=new OutputStreamWriter(fos, "UTF-8");
            BufferedWriter  bw=new BufferedWriter(osw);
            //简写如下：
            //BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(
            //        new FileOutputStream(new File("E:/phsftp/evdokey/evdokey_201103221556.txt")), "UTF-8"));
    
            for(String arr:arrs){
                bw.write(arr+"\t\n");
            }
    
            //注意关闭的先后顺序，先打开的后关闭，后打开的先关闭
            bw.close();
            osw.close();
            fos.close();
        }
    }