Blame view

src/main/java/com/example/demo/service/impl/SNServiceImpl.java 5.05 KB
9f87bede   岑健浩   SNManage init
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
  package com.example.demo.service.impl;
  
  import cn.hutool.core.codec.Base64;
  import com.example.demo.exception.SNRepetitiveException;
  import com.example.demo.service.SNService;
  import org.springframework.beans.factory.annotation.Value;
  import org.springframework.stereotype.Service;
  
  import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import java.io.*;
  import java.util.HashSet;
  import java.util.Set;
  import java.util.concurrent.locks.Lock;
  import java.util.concurrent.locks.ReentrantLock;
  
  @Service
  public class SNServiceImpl implements SNService {
      /**
       *  多线程改写文件存在并发问题,需加锁操作
       */
      private static final Lock lock = new ReentrantLock();
  
      @Value("${SN.file.path}")
      String SNFilePath;
  
      @Value("${SN.file.temp.path}")
      String SNTempFilePath;
  
      @Override
      public void addSN(String SNDto) throws SNRepetitiveException, IOException {
          //加try,catch只为释放锁
          try {
              //加锁
              lock.lock();
  
              //读取文件,判断SN是否重复
              Set<String> set = new HashSet<>();
              BufferedReader bufferedReader = new BufferedReader(new FileReader(SNFilePath));
              String br;
              while ((br=bufferedReader.readLine()) != null) {
                  //截取SN
                  int index = br.indexOf('#');
                  String SN = br.substring(0,index == -1? 0 : index);
                  set.add(SN);
              }
  
              String addSn = SNDto.substring(0,SNDto.indexOf('#'));
              if (set.contains(addSn)) {
                  throw new SNRepetitiveException("SN:" + addSn + " 已存在,请勿重复添加");
              }
  
              //写入
              FileWriter fileWriter = new FileWriter(SNFilePath,true);
              fileWriter.write(SNDto+System.lineSeparator());
              fileWriter.flush();
              fileWriter.close();
          } finally { //释放锁
              lock.unlock();
          }
      }
  
      @Override
      public String getEncryptSNs() throws IOException {
          File file = new File(SNFilePath);
          //读取文件
          byte[] SNsByteArr = new byte[(int) file.length()];
          FileInputStream fileInputStream = new FileInputStream(file);
          fileInputStream.read(SNsByteArr);
          //加密
          String encodeSNs = Base64.encode(SNsByteArr);
  
          return encodeSNs;
      }
  
      @Override
      public void deleteSN(String SN) throws Exception{
          try {
              lock.lock();
  
              //读取文件,记录不用删除的数据
              BufferedReader bufferedReader = new BufferedReader(new FileReader(SNFilePath));
              String br;
              StringBuilder stringBuilder = new StringBuilder();
              boolean SNExist = false;
              while ((br=bufferedReader.readLine()) != null) {
                  //截取SN
                  int index = br.indexOf('#');
                  String str = br.substring(0,index == -1? 0 : index);
                  if (!SN.equals(str)) {
                      stringBuilder.append(br);
                      stringBuilder.append(System.lineSeparator());
                  } else {
                      SNExist = true;
                  }
              }
              bufferedReader.close();
  
              //如果存在要删除的SN,先将数据备份,再将留存数据覆盖掉原SN文件,避免数据写一半断电丢失。
              if (SNExist) {
                  //备份数据
                  FileWriter SNTempfileWriter = new FileWriter(SNTempFilePath);
                  SNTempfileWriter.write(stringBuilder.toString());
                  SNTempfileWriter.flush();
                  SNTempfileWriter.close();
                  //覆盖掉原来的数据到SN文件中
                  FileWriter SNfileWriter = new FileWriter(SNFilePath);
                  SNfileWriter.write(stringBuilder.toString());
                  SNfileWriter.flush();
                  SNfileWriter.close();
  
              }
  
  
          } finally {
              lock.unlock();
          }
      }
  
      @Override
      public void downloadSNFile(HttpServletRequest request, HttpServletResponse response) throws IOException {
          File file = new File(SNFilePath);
  
          response.setCharacterEncoding("UTF-8");
          response.setHeader("Content-type","application/octet-stream;charset=UTF-8");
          response.setHeader("Content-Disposition", "attachment;filename=" + java.net.URLEncoder.encode(file.getName().trim(), "UTF-8"));
          response.addHeader("Pargam", "no-cache");
          response.addHeader("Cache-Control", "no-cache");
  
          //读取文件
          byte[] SNsByteArr = new byte[(int) file.length()];
          FileInputStream fileInputStream = new FileInputStream(file);
          fileInputStream.read(SNsByteArr);
          //加密
          String encodeSNs = Base64.encode(SNsByteArr);
  
          //写入到输出流
          response.addHeader("Content-Length",String.valueOf(encodeSNs.getBytes().length));
          OutputStream outputStream = response.getOutputStream();
          outputStream.write(encodeSNs.getBytes());
          outputStream.flush();
          outputStream.close();
  
      }
  
  }