java-实现修改文件内容(1)

对于如何修改某个文件的内容，写了许多方法，目前的方法是 1.根据固定行数修改文本内容 2.根据有特殊字符修改内容 3.对文本进行数据插入

本篇主要是对文本固定行数修改内容展开，代码如下：

/**
     * 根据行号修改文件内容
     *
     * @param path
     * @param replaceList
     */
    public static void rpFileContentByLineNo(String path, List<LineReplaceEntity> replaceList) {
        File file = new File(path);
        BufferedReader br = null;
        FileReader in = null;
        // 内存流, 作为临时流
        CharArrayWriter tempStream = null;
        FileWriter out = null;
        int maxLineNo = getMaxLineNo(replaceList);
        int index = 0;
        try {
            in = new FileReader(file);
            br = new BufferedReader(in);
            // 内存流, 作为临时流
            tempStream = new CharArrayWriter();
            // 替换
            String line = null;
            while ((line = br.readLine()) != null) {
                index++;
                if (index <= maxLineNo) {
                    for (LineReplaceEntity rpEntity : replaceList) {
                        if (index == rpEntity.getLineNo()) {
                            line = rpEntity.getReplaceStr();
                        }
                    }
                }
                // 将该行写入内存
                tempStream.write(line);
                // 添加换行符
                tempStream.append(System.getProperty("line.separator"));
            }
            // 将内存中的流 写入 文件
            out = new FileWriter(path);
            tempStream.writeTo(out);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            IOUtils.closeQuietly(tempStream);
            IOUtils.closeQuietly(out);
            IOUtils.closeQuietly(br);
            IOUtils.closeQuietly(in);
        }
    }

package com.rmis.common.utils.dat;
 
/**
 * @ClassName LineReplaceEntity
 * @Description TODO
 * @Author lxp
 * @Date 2020/06/17 10:29
 */
public class LineReplaceEntity {
 
    private static final long serialVersionUID = 1L;
 
    /**
     * 行号
     */
    private int lineNo;
 
    /**
     * 替换内容
     */
    private String replaceStr;
 
    public int getLineNo() {
        return lineNo;
    }
 
    public void setLineNo(int lineNo) {
        this.lineNo = lineNo;
    }
 
    public String getReplaceStr() {
        return replaceStr;
    }
 
    public void setReplaceStr(String replaceStr) {
        this.replaceStr = replaceStr;
    }
 
    public LineReplaceEntity(int lineNo, String replaceStr) {
        this.lineNo = lineNo;
        this.replaceStr = replaceStr;
    }
}

最后测试：

    public static void main(String[] args) {
        List<LineReplaceEntity> list = new ArrayList<>();
        //将第二行替换为你想要的内容
        list.add(new LineReplaceEntity(2,"test"));
        rpFileContentByLineNo("D:\\1.dat",list);
    }