package?raw;

class?DataFile?{

????//表示正在進行讀取操作的人數
????private?int?readerCount;
????//doreading?表示讀信號量?當?doreading?=?true?時?表示有線程在讀無法進行寫操作
????private?boolean?doreading;
????//dowriting?表示寫信號量?當?dowriting?=?true?時?表示有線程在寫無法進行讀操作??????如何解決一個線程在寫讓另外其他的不能寫？
????private?boolean?dowriting;
????private?int?www;

????public?DataFile（）?{
????????readerCount?=?0;
????????doreading?=?false;
????????dowriting?=?false;
????????www?=?0;
????}

????public?static?void?naps（）?{
????????try?{
????????????Thread.sleep（（int）?（4000?*?Math.random（）））;
????????}?catch?（InterruptedException?e）?{
????????????e.printStackTrace（）;
????????}
????}

????public?synchronized?int?startRead（）?//開始讀操作
????{
????????while?（dowriting?==?true）?//?當有寫線程在完成寫操作時??讀線程等待寫線程喚醒
????????{
????????????try?{
????????????????System.out.println（Thread.currentThread（）.getName（）?+?“臨界資源被占用“）;
????????????????//等待寫者發出notify
????????????????wait（）;
????????????}?catch?（InterruptedException?e）?{
????????????????e.printStackTrace（）;
????????????}
????????}
????????while（true）????
????????{
?????????????if?（www?==?0）?{
????????????????System.out.println（Thread.currentThread（）.getName（）?+?“開始進行讀操作“）;
????????????????readerCount++;
????????????????break;
????????????}?else?{
????????????????try?{
????????????????wait（）;
????????????}?catch?（InterruptedException?e）?{
????????????????e.printStackTrace（）;
????????????}
????????????}
????????}

????????if?（readerCount?>=?1）?{
????????????doreading?=?true;
????????}
????????return?readerCount;
????}

????public?synchronized?int?endRead（）?//結束讀操作
????{
????????--readerCount;

????????if?（readerCount?==?0）?{
????????????doreading?=?false;
????????}
????????notifyAll（）;
????????System.out.println（Thread.currentThread（）.getName（）?+?“讀操作結束“）;
????????if（readerCount==0）
????????{
?????????System.out.println（“此時無讀者在讀，臨界資源釋放“）;
????????}

????????return?readerCount;
????}

????public?synchronized?void?startWrite（）?//開始寫操作
????{
????????www++;
????????while?（doreading?==?true?||?dowriting?==?true）?{
????????????try?{
????????????????System.out.println（Thread.currentThread（）.getName（）?+?“臨界資源被占用“）;
????????????????//等待讀者或者寫者發出信息
????????????????wait（）;
????????????}?catch?（InterruptedException?e）?{
????????????????e.printStackTrace（）;
????????????}
????????}

????????System.out.println（Thread.currentThread（）.getName（）?+?“開始進行寫操作“）;
????????dowriting?=?true;
????}

????public?synchronized?void?endWrite（）?//結束寫操作
????{
????????--www;
????????dowriting?=?false;
????????notifyAll（）;
????????System.out.println（Thread.currentThread（）.getName（）?+?“寫操作結束，釋放臨界資源“）;
????}
}

class?Reader?implements?Runnable?{

????private?int?readerNum;

????private?DataFile?df;

????Reader（int?readerNum?DataFile?df）?{
????????this.readerNum?=?readerNum;
????????this.df?=?df;
????}

????public?void?run（）?{
????????df.naps（）;
????????df.startRead（）;
????????df.naps（）;
????????

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----
?????目錄???????????0??2018-05-23?12:07??RAW\
?????文件????????3594??2018-05-23?11:56??RAW\build.xml
?????目錄???????????0??2018-05-23?12:07??RAW\build\
?????目錄???????????0??2018-05-23?12:07??RAW\build\classes\
?????文件???????????0??2018-05-23?12:07??RAW\build\classes\.netbeans_automatic_build
?????文件???????????0??2018-05-23?12:07??RAW\build\classes\.netbeans_update_resources
?????目錄???????????0??2018-05-23?12:07??RAW\build\classes\raw\
?????文件????????2237??2018-05-23?12:07??RAW\build\classes\raw\DataFile.class
?????文件????????1112??2018-05-23?12:07??RAW\build\classes\raw\RAW.class
?????文件??????????47??2018-05-23?12:07??RAW\build\classes\raw\RAW.rs
?????文件?????????605??2018-05-23?12:07??RAW\build\classes\raw\Reader.class
?????文件?????????599??2018-05-23?12:07??RAW\build\classes\raw\Writer.class
?????文件??????????85??2018-05-23?11:56??RAW\manifest.mf
?????目錄???????????0??2018-05-23?11:56??RAW\nbproject\
?????文件???????79614??2018-05-23?11:56??RAW\nbproject\build-impl.xml
?????文件?????????475??2018-05-23?11:56??RAW\nbproject\genfiles.properties
?????目錄???????????0??2018-05-23?12:10??RAW\nbproject\private\
?????文件?????????112??2018-05-23?11:56??RAW\nbproject\private\private.properties
?????文件?????????427??2018-05-23?12:10??RAW\nbproject\private\private.xml
?????文件????????2461??2018-05-23?11:56??RAW\nbproject\project.properties
?????文件?????????511??2018-05-23?11:56??RAW\nbproject\project.xml
?????目錄???????????0??2018-05-23?11:56??RAW\src\
?????目錄???????????0??2018-05-23?11:56??RAW\src\raw\
?????文件????????4527??2018-05-23?12:07??RAW\src\raw\RAW.java
?????目錄???????????0??2018-05-23?11:57??RAW\test\
?????目錄???????????0??2018-05-22?22:33??RW\
?????文件????????3591??2018-05-22?21:54??RW\build.xml
?????目錄???????????0??2018-05-22?22:33??RW\build\
?????目錄???????????0??2018-05-22?22:33??RW\build\classes\
?????文件???????????0??2018-05-22?22:33??RW\build\classes\.netbeans_automatic_build
?????文件???????????0??2018-05-22?22:33??RW\build\classes\.netbeans_update_resources
............此處省略48個文件信息