java一行一行写入或读取数据

Posted 2020-08-07 imsoft.cnblogs

原文：http://www.cnblogs.com/linjiqin/archive/2011/03/23/1992250.html

假如E:/phsftp/evdokey目录下有个evdokey_201103221556.txt文件，

现在对evdokey_201103221556.txt文件进行写入或读取操作，并解决写入或读取出现的乱码问题。

               

文件内容如：

zhangsan,23,福建 lisi,30,上海 wangwu,43,北京 laolin,21,重庆 ximenqing,67,贵州

                

代码如下：

/**
     * 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("E:/phsftp/evdokey/evdokey_201103221556.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]);
        }
        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();
    }