| 001 002 003 004 005 006 007 008 009 010 011 012 013 014 015 016 017 018 019 020 021 022 023 024 025 026 027 028 029 030 031 032 033 034 035 036 037 038 039 040 041 042 043 044 045 046 047 048 049 050 051 052 053 054 055 056 057 058 059 060 061 062 063 064 065 066 067 068 069 070 071 072 073 074 075 076 077 078 079 080 081 082 083 084 085 086 087 088 089 090 091 092 093 094 095 096 097 098 099 100 101 102 103 104 105 106 107 108 109 | import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; /** * 单例模式实现 * * @author king * */ public class FileCounter { public static FileCounter counter; private String fileName; private int count; private FileCounter(String fileName) { super(); this.fileName = fileName; } public static synchronized FileCounter getInstance(String fileName) { if (counter == null) { counter = new FileCounter(fileName); } return counter; } public int getNextValue() { ObjectInputStream ois = null; ObjectOutputStream oos = null; try { File file = new File(this.fileName); if (!file.exists()) { file.createNewFile(); oos = new ObjectOutputStream(new FileOutputStream(file)); oos.writeInt(1); this.count = 1; } else { ois = new ObjectInputStream(new FileInputStream(file)); int tmp = ois.readInt(); oos = new ObjectOutputStream(new FileOutputStream(file)); tmp++; oos.writeInt(tmp); this.count = tmp; } return this.count; } catch (Exception e) { e.printStackTrace(); } finally { try { if (ois != null) { ois.close(); } } catch (IOException e) { e.printStackTrace(); } try { if (oos != null) { oos.close(); } } catch (IOException e) { e.printStackTrace(); } } return this.count; } /** * @param args */ public static void main(String[] args) { FileCounter counter = FileCounter.getInstance("counter.txt"); System.out.println("开始计时:"); for (int i = 0; i < 10; i++) { System.out.println(counter.getNextValue()); } System.out.println("结束计时!\n"); } } |
