JAVA读写文件小实例

喜欢ヅ旅行 2022-04-11 12:39 240阅读 0赞

测试同事在测试时，需要测试一些比较特殊的场景，需要往第三方的文件中新增数据，而第三方文件内容是以特殊的\\u0001做为分隔符的，用普通的文本编辑工具打开是乱码。因此，特写了一个文件操作的小程序给测试同事。

小程序功能：往第三方文件中新增数据，新增的数据是以“|”分隔的。当然，对readDataFromFile方法稍加修改，也可以从文件中读取数据。

FileUtils.java

package com.bijian.tools;
    
    import java.io.BufferedReader;
    import java.io.BufferedWriter;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStreamReader;
    import java.io.OutputStreamWriter;
    import java.util.ArrayList;
    import java.util.List;
    
    import org.apache.commons.collections.CollectionUtils;
    import org.apache.commons.lang.StringUtils;
    
    import com.google.common.base.Splitter;
    import com.google.common.io.Closeables;
    
    public class FileUtils {
        
        private final static String CHARACTER_ENCODING_UTF_8 = "UTF-8";
        private final static String SPLIT_CHAR = "\u0001";
        private final static String LOCAL_SPLIT_CHAR = "|";
        
        private final static String FILE_NAME_WITH_PATH = "D:\\data\\files\\test.txt";
        
        public static void main(String[] args) {
            
            List<String> data = new ArrayList<String>();
            data.add("123456789|201|301|20170124|153401");
            data.add("222222222|202|302|20170124|153501");
            
            List<DataDto> dataList = new ArrayList<DataDto>();
            
            for(String line : data) {
                parseLineAndAdd(line, dataList);
            }
            generateCompareFile(FILE_NAME_WITH_PATH, dataList);
        }
    
        /**
         * 从文件中读取数据
         * @return
         */
        private static List<DataDto> readDataFromFile() {
            
            List<DataDto> dataList = new ArrayList<DataDto>();
            BufferedReader reader = null;
            try {
                reader = new BufferedReader(new InputStreamReader(new FileInputStream(FILE_NAME_WITH_PATH)));
                String lineStr;
                while ((lineStr = reader.readLine()) != null) {
                    parseLineAndAdd(lineStr, dataList);
                }
            }catch(Exception e) {
                System.err.println("读取文件出错," + e);
            }finally {
                try {
                    if(reader != null) {
                        Closeables.close(reader, false);
                    }
                } catch (IOException e) {
                        reader = null;
                } finally {
                        reader = null;
                }
            }
            return dataList;
        }
        
        private static void parseLineAndAdd(String line, List<DataDto> dataList) {
            
            List<String> lineData = Splitter.on(LOCAL_SPLIT_CHAR).splitToList(line);
            if (CollectionUtils.isNotEmpty(lineData)) {
    
                DataDto data = new DataDto();
                
                data.setId(lineData.get(0));
                data.setbCode(lineData.get(1));
                data.setcCode(lineData.get(2));
                data.setDate(lineData.get(3));
                data.setTime(lineData.get(4));
    
                dataList.add(data);
            }
        }
        
        /**
         * 根据指定的文件全路径创建空白文件
         */
        public static void createNewFile(String fileName) {
            String dir = fileName.substring(0, fileName.lastIndexOf(File.separator));
            File dirs = new File(dir);
            if (!dirs.exists()) {
                dirs.mkdirs();
            }
    
            if (!dirs.mkdirs() && !dirs.isDirectory()) {
                System.out.println((new StringBuilder("Unable to create directory ")).append(dirs).toString());
            }
    
            File file = new File(fileName);
            try {
                if(file.exists()){
                    file.delete();
                }
                file.createNewFile();
            } catch (IOException e) {
                System.out.println(new StringBuffer("Create File ").append(fileName).append(" happen error,reason:").append(e.toString()).toString());
            }
        }
        
        private static void generateCompareFile(String fileName, List<DataDto> dataList) {
    
            BufferedWriter bufferedWriter = null;
            try {
                bufferedWriter = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileName, true),
                        CHARACTER_ENCODING_UTF_8));
                System.out.println("文件写入开始");
                if (!(CollectionUtils.isEmpty(dataList))) {
                    for (DataDto temp : dataList) {
                        writeCoreCompareFileToWriter(bufferedWriter, temp);
                    }
                } else {
                    System.out.println("无数据写入");
                }
                System.out.println("文件写入结束");
            } catch (Exception e) {
                System.err.println("文件写入过程出现异常:" + e);
            } finally {
                try {
                    Closeables.close(bufferedWriter, false);
                } catch (IOException e) {
                    System.err.println("关闭IO流失败" + e);
                } finally {
                    bufferedWriter = null;
                }
            }
        }
        
        private static void writeCoreCompareFileToWriter(BufferedWriter bufferedWriter, DataDto data)
                throws Exception {
            
            StringBuilder line = new StringBuilder();
            
            line.append(StringUtils.defaultIfEmpty(data.getId(), "")).append(SPLIT_CHAR)
                .append(StringUtils.defaultIfEmpty(data.getbCode(), "")).append(SPLIT_CHAR)
                .append(StringUtils.defaultIfEmpty(data.getcCode(), "")).append(SPLIT_CHAR)
                .append(StringUtils.defaultIfEmpty(data.getDate(), "")).append(SPLIT_CHAR)
                .append(StringUtils.defaultIfEmpty(data.getTime(), "")).append(SPLIT_CHAR);
            
            bufferedWriter.write(line.toString());
            bufferedWriter.write("\n");
        }
    }

DataDto.java

package com.bijian.tools;
    
    public class DataDto {
        
        private String id;
    
        private String bCode;
    
        private String cCode;
    
        private String date;
    
        private String time;
    
        public String getId() {
            return id;
        }
    
        public void setId(String id) {
            this.id = id;
        }
    
        public String getbCode() {
            return bCode;
        }
    
        public void setbCode(String bCode) {
            this.bCode = bCode;
        }
    
        public String getcCode() {
            return cCode;
        }
    
        public void setcCode(String cCode) {
            this.cCode = cCode;
        }
    
        public String getDate() {
            return date;
        }
    
        public void setDate(String date) {
            this.date = date;
        }
    
        public String getTime() {
            return time;
        }
    
        public void setTime(String time) {
            this.time = time;
        }
    }