java读取文件后修改，并写入到另一个文件

来源：互联网发布：mac在哪里新建文件夹编辑：程序博客网时间：2024/05/17 02:21
首先，用java读取文件和写入文件都其实很简单，但重点是修改文件。
修改可以为替换、删除、新增字符。所以不能用inputstream那种字节流的方式，以下例子使用BufferedReader的方式来读取每行的字符数据。
完成一个Util java文件如下：
主要要用到common-io.jar 包，其中有一些正则表达式规则来做替换工作。
package com.zjhc.hcdream.util;import java.io.*;import java.util.ArrayList;import java.util.List;import java.util.regex.Matcher;import java.util.regex.Pattern;/** * Created by Gerrard on 2016-9-14. */public class TransformUtil {    public static void main(final String[] args) throws Exception {        String inFile = "D:/3XDATA/test/"; // 输入文件路径        String outFile = "D:/3XDATA/out/"; // 输出文件路径        String paths="/user/hive/ggzyjy/";        String dbo="ggzyjy";        File file=new File(inFile);        File[] tempList = file.listFiles();        for (int i = 0; i < tempList.length; i++) {            if (tempList[i].isFile()) {                tranformMethod(tempList[i].toString(),outFile,paths,dbo);            }        }    }    public static void tranformMethod(String inFile,String outFile,String paths,String dbo) throws IOException {        String fileName="";        BufferedReader bs  = null;        BufferedWriter bw = null;        try{            bs = new BufferedReader(new FileReader(new File(inFile)));            List<String> outData =  new ArrayList<String>();            String line = null;            String[] data = null;            //如果确定ID1一直是整数的活，可以用整数比，否则可以用字符串的equals比较            int oldId1 = 0;            int newId1 = 0;            int oldId2 = -1;            int newId2 = -1;            int num=0;            int count=0;            while((line = bs.readLine()) != null){                String lowLine=line.toLowerCase();                // 把所有[]都去掉                lowLine=lowLine.replace("[","");                lowLine=lowLine.replace("]","");                if(num==1){ // 字符修改处                    // 将Table换成                    if(lowLine.contains("table")){                        lowLine=lowLine.replace("table","external table");                        lowLine=lowLine.replace("dbo","ggzyjy");                        // 获取表明                        Pattern pattern = Pattern.compile("ggzyjy.(.*)\\($");                        Matcher matcher = pattern.matcher(lowLine);                        while(matcher.find()){                            fileName=matcher.group(1);                            fileName=fileName.trim();                        }                    }                    if(count==1){// 加固操作，只改()里面的                        // 替换字符类型                        boolean flag=false;                        String[] regex = {"nvarchar.*,$","datetime.*,$","bit.*,$","varchar.*,$","timestamp .*,$",                                "date.*,$","ntext.*,$","int.*,$","bigint.*,$","float.*,$","double.*,$","numeric.*,$","nvarchar.*\\s+$","datetime.*\\s+$","bit.*\\s+$","varchar.*\\s+$","timestamp .*\\s+$",                                "date.*\\s+$","ntext.*\\s+$","int.*\\s+$","bigint.*\\s+$","float.*\\s+$","double.*\\s+$","numeric.*\\s+$"};// 设置最后一行不以逗号结尾的行                        String[] regex1={"nvarchar.*","datetime.*","bit.*","varchar.*","timestamp .*",                                "date.*","ntext.*","int.*","bigint.*","float.*","double.*","numeric.*\\s+$"};                        for(int i=0;i<regex.length;i++){                            Pattern pattern = Pattern.compile(regex[i]);                            Matcher matcher = pattern.matcher(lowLine);                            if(regex[i].startsWith("int") && regex[i].endsWith(",$")){                                lowLine = matcher.replaceAll("int ,");                            }else if(regex[i].startsWith("bigint")  && regex[i].endsWith(",$")){                                lowLine = matcher.replaceAll("bigint ,");                            }else if(regex[i].startsWith("float")  && regex[i].endsWith(",$")){                                lowLine = matcher.replaceAll("float ,");                            }else if(regex[i].startsWith("double")  && regex[i].endsWith(",$")){                                lowLine = matcher.replaceAll("double ,");                            }else if(regex[i].startsWith("numeric")  && regex[i].endsWith(",$")){                                lowLine = matcher.replaceAll("double ,");                            }else if(regex[i].startsWith("int")  && regex[i].endsWith("+$")){                                lowLine = matcher.replaceAll("int");                            }else if(regex[i].startsWith("bigint")  && regex[i].endsWith("+$")){                                lowLine = matcher.replaceAll("bigint");                            }else if(regex[i].startsWith("float")  && regex[i].endsWith("+$")){                                lowLine = matcher.replaceAll("float");                            }else if(regex[i].startsWith("double")  && regex[i].endsWith("+$")){                                lowLine = matcher.replaceAll("double");                            }else if(regex[i].startsWith("numeric")  && regex[i].endsWith("+$")){                                lowLine = matcher.replaceAll("double");                            }else{                                if(regex[i].endsWith("+$")){                                    lowLine = matcher.replaceAll("string ");                                }                                if(regex[i].endsWith(",$")){                                    lowLine = matcher.replaceAll("string ,");                                }                            }                        }                    }                    if(count==2){                        String str="row format delimited\n" +                                "fields terminated by '\\t' \n" +                                "STORED AS TEXTFILE \n" +                                "location '"+paths+fileName+"' ;";                        outData.add(str);                        count++;                    }                    if(lowLine.endsWith("(") || lowLine.endsWith(")")){                        count++;                    }                    if(!lowLine.equals("go")){                        outData.add(lowLine);                    }                }                if(lowLine.equals("go")){                    num++;                }            }            // 在最后要新增的行数据            if(!outData.isEmpty()){                bw = new BufferedWriter(new FileWriter(new File(outFile+fileName+".sql")));                for(String s : outData){                    bw.write(s + "\r\n");                }            }        }catch(Exception e){            e.printStackTrace();        }finally{            if(bs != null){                bs.close();            }            if(bw != null){                bw.close();            }        }    }}
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