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http断点续传简单实现(java)

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/* $[=`*m  
**SiteFileFetch.java |@-y+vbA*  
*/ . 55aY~We  
package NetFox; q|D*H9[ke  
import java.io.*; g=v[@{9Pw  
import java.net.*; y7*^H  
lgAE`Os  
Ke&fTK  
public class SiteFileFetch extends Thread { m} =<@b:l  
@D<Q'7mLh  
Q([g1?F9*  
SiteInfoBean siteInfoBean = null; //文件信息Bean wVs|mG"  
long[] nStartPos; //开始位置 ',RR*{I  
long[] nEndPos; //结束位置 7xT<|3 I  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 inGH'nl_  
long nFileLength; //文件长度 ;#"`]khd  
boolean bFirst = true; //是否第一次取文件 zwHTtE  
boolean bStop = false; //停止标志 gwF@'Uu  
File tmpFile; //文件下载的临时信息 `+@%l*TQ  
DataOutputStream output; //输出到文件的输出流 WUi7~Ei}  
lu.2ZQE  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类)  6Ue6b$xE  
public SiteFileFetch(SiteInfoBean bean) throws IOException Un[#zh<4  
{ WqU$cQD"  
siteInfoBean = bean; g(;ejKSR  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z#*GPA8Em:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); veE8 N~0N.  
if(tmpFile.exists ()) !*#=7^#  
{ q+G1#5  
bFirst = false; _H3cqD  
read_nPos(); QnOa?0HL/  
} RMrt4:-DI  
else eaiz w@N  
{ %F/tbXy{  
nStartPos = new long[bean.getNSplitter()]; @o^sp|k !  
nEndPos = new long[bean.getNSplitter()]; ;NPb  
} -s!PO;qm  
`RzM)ILl  
O 1X !  
2Uk8{d  
} bKaV]Uy  
Rx<pV_|H,  
n<$I,IRE  
public void run() T<=\5mn  
{ ,^,J[F  
//获得文件长度 BzUx@,  
//分割文件 4* hmeS"  
//实例FileSplitterFetch  JuI,wA  
//启动FileSplitterFetch线程 gR>#LM&dG  
//等待子线程返回 ^~I  
try{ QBo^{],  
if(bFirst) \%VoX` B  
{ zj)[Sn tn?  
nFileLength = getFileSize(); y|mR'{$I  
if(nFileLength == -1) dk ?0r  
{ Y+7v~/K=  
System.err.println("File Length is not known!"); Z n!SHj  
} S9BJjo  
else if(nFileLength == -2) {gn[ &\  
{ P$QfcJq&c*  
System.err.println("File is not access!"); ^YZ#P0 y  
} m1hf[cg  
else m ;vNA  
{ g<-cHF  
for(int i=0;i<nStartPos.length;i++) Mf63 59  
{  h 2zCX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); RinRQd  
} N!3f1d7RQ  
for(int i=0;i<nEndPos.length-1;i++) b +_E)4  
{ nNKL{Hp  
nEndPos = nStartPos[i+1]; S'e2~-p0F  
} 3WY W])  
nEndPos[nEndPos.length-1] = nFileLength; _V?Q4}7d/  
} ;D7jE+  
} ^b#E%Rd  
9+']`=a:  
=EJ"edw]%0  
//启动子线程 a*8}~p,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {mQJ6 G'ny  
for(int i=0;i<nStartPos.length;i++) #wyS?FP-  
{ qGqu/$bh  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -iHhpD9"X  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), bW]+Og  
nStartPos,nEndPos,i); G dU W$.  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2 *$n?  
fileSplitterFetch.start(); %r"GL  
} u| c+w)a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DvCt^O*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); #`$7$Y~]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", qg/5m;U  
nEndPos = " + nFileLength); "q .uiz+1:  
// fileSplitterFetch[nPos.length-1].start(); Dhoj|lc  
+q$|6?  
;GS JnV  
//等待子线程结束 fL;p^t u3  
//int count = 0; M\f0 =`g  
//是否结束while循环 d#Ajb  
boolean breakWhile = false; M6sDtL9l  
C.-a:oQ[  
jxaoQeac  
while(!bStop) @U JmbD{  
{ ]r6bJ 2  
write_nPos(); eZi<C}z  
Utility.sleep(500); E6k&r}  
breakWhile = true; ay4xOwcR  
Uj)]nJX  
<4,?lZ  
for(int i=0;i<nStartPos.length;i++) *lAdS]I  
{ Gu).*cU  
if(!fileSplitterFetch.bDownOver) 8A.7=C' z  
{ 8)8oR&(f  
breakWhile = false; F.D1;,x  
break; x["  
} I:<R@V<~#  
} !++62Lf  
if(breakWhile) /g''-yT7#  
break; YPnJldVn  
u0b-JJ7)BQ  
sEyl\GL  
//count++; S45>f(!  
//if(count>4) 5i#w:O\cz  
// siteStop(); ^^l"brPa  
} 9G+rxyWMW  
D:tZiS=0  
ycD.:w p\'  
System.err.println("文件下载结束!"); YCO:bBmp:  
} T(^8ki  
catch(Exception e){e.printStackTrace ();} gq3OCA!cX  
} GuvF   
w tLM c  
mtddLd,  
//获得文件长度 e622{dfVS  
public long getFileSize() v^fOT5\  
{ lG>e6[Wc  
int nFileLength = -1; ^\jX5)2{  
try{ W%K8HAP"  
URL url = new URL(siteInfoBean.getSSiteURL()); 4CT9-2UC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z,YUguc|  
httpConnection.setRequestProperty("User-Agent","NetFox"); S=SncMO nE  
Cpv%s 1M  
bGc|SF<V  
int responseCode=httpConnection.getResponseCode(); 3>)BI(Wl  
if(responseCode>=400) Lu.tRZ`$38  
{ '<S:|$ $  
processErrorCode(responseCode); >[4|6k|\x  
return -2; //-2 represent access is error .WyX/E$I^!  
} y4rJ-  
5G;^OI!g  
3MJWCo-[  
String sHeader; O \8G~V 5"  
5XO'OSdYq  
![ID0}MjJ  
for(int i=1;;i++) n4T2'e  
{ {eN{Zh5"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %&+R":Bw  
//Utility.log(in.readLine()); Prz +kPP  
sHeader=httpConnection.getHeaderFieldKey(i); Ds,"E#?  
if(sHeader!=null) ef:$1VIBda  
{ J*KBG2+13  
if(sHeader.equals("Content-Length")) qZ_fQ@   
{ PG[O?l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); BBE1}V!u  
break; o+Ti$`2<O7  
} ss@}Dt^  
} X8n/XG~_  
else JX$NEq(  
break; \ +-hn  
} `=$jc4@J  
} Q*&aC|b&  
catch(IOException e){e.printStackTrace ();} (VPM>ndkw  
catch(Exception e){e.printStackTrace ();} 1S]gD&V  
n.6 0$kR`  
3/IWO4?_  
Utility.log(nFileLength);  )P9{47  
A.C278^O8  
6O@ ^`T  
return nFileLength; Fp6[W5>(-  
} mx(%tz^t  
~muIi#4  
/xm#:+Sc  
//保存下载信息(文件指针位置) ivUsMhx>S,  
private void write_nPos() NRuG?^/}d  
{ &J/4J  
try{ LXu"rfp  
output = new DataOutputStream(new FileOutputStream(tmpFile)); iraRB~  
output.writeInt(nStartPos.length); kl3S~gE4@  
for(int i=0;i<nStartPos.length;i++) MLD>"W  
{ "kBqY+:Cn  
// output.writeLong(nPos); P2Qyz}!wo  
output.writeLong(fileSplitterFetch.nStartPos); r {B,uj"  
output.writeLong(fileSplitterFetch.nEndPos); 0.BUfuuh  
} & kjwIg{  
output.close(); fzFvfMAU  
} R4~zL!7;  
catch(IOException e){e.printStackTrace ();} Wt)SdF=U/  
catch(Exception e){e.printStackTrace ();} ZH$sMh<xg  
} ZOrTbik  
)lDIzLp  
L^ #<HQ  
//读取保存的下载信息(文件指针位置) ,+f0cv4  
private void read_nPos() m~j\?mb{+  
{ ~Ri u*<  
try{ 'D0X?2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); R|)2Dg  
int nCount = input.readInt(); |N=@E,33  
nStartPos = new long[nCount]; [ 4Y `O  
nEndPos = new long[nCount]; `k}l$ih`X  
for(int i=0;i<nStartPos.length;i++) ,8xP8T~Kmv  
{ kF+}.x%  
nStartPos = input.readLong(); >xZhK63C/  
nEndPos = input.readLong(); VM]GYz|#]  
} N{hF [F  
input.close(); @ Zgl>  
} 4/`h@]8P  
catch(IOException e){e.printStackTrace ();} Zu0;/_rN  
catch(Exception e){e.printStackTrace ();} rxy{a  
} Yf!*OGF  
QLB1:O>  
Y0 X"Zw  
private void processErrorCode(int nErrorCode) )p!*c,  
{ Rgfc29(8  
System.err.println("Error Code : " + nErrorCode); 3u?`q%Y-e  
} n(Q\' ,C  
i (%tHa37  
$p0 /6c  
//停止文件下载 |,1bkJt  
public void siteStop() /Oggt^S  
{ vhYMWfbY  
bStop = true; 4j=<p@  
for(int i=0;i<nStartPos.length;i++) >9.5-5"   
fileSplitterFetch.splitterStop(); MS st  
sw41wj  
B|Fl ,55  
} +-H}s`  
} 42V,PH6o  
//负责部分文件的抓取 7>'uj7r]=  
**FileSplitterFetch.java %Le:wC  
*/ @q> ktE_  
package NetFox; w~kHQ%A  
~9JW#HHzn  
"t[M'[ `C  
import java.io.*; E /fw?7eQ  
import java.net.*; w`c0a&7  
u(pdP"  
"wA0 LH_  
public class FileSplitterFetch extends Thread { kAZC"qM%i  
Qw24/DJK  
xn(+G$m  
String sURL; //File URL ?mH@`c,fM  
long nStartPos; //File Snippet Start Position iD>G!\&  
long nEndPos; //File Snippet End Position -"W)|oC_  
int nThreadID; //Thread's ID \*f;!{P{  
boolean bDownOver = false; //Downing is over t *{,Gk  
boolean bStop = false; //Stop identical j~M#Ss-H8  
FileAccessI fileAccessI = null; //File Access interface x}tKewdOSe  
<jbj/Q )"  
Wgxn`6  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /Zo~1q  
{ P3'2IzNw  
this.sURL = sURL; +"]oc{W!  
this.nStartPos = nStart; Zxg1M  
this.nEndPos = nEnd; {5T0RL{\N  
nThreadID = id; 9*#$0Y=  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m)s xotgXf  
} <"* "1(wN  
ZhH+D`9  
mfXD1]<.  
public void run() Q]< (bD.7  
{ +"'F Be  
while(nStartPos < nEndPos && !bStop) ]]>nbgGn#  
{ H76E+AY  
}<vvxi  
Vy]A,Rn7  
try{ B,3 t`  
URL url = new URL(sURL); 9'1hjd3k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l`SK*Bm~<  
httpConnection.setRequestProperty("User-Agent","NetFox"); ./$ <J6-J  
String sProperty = "bytes="+nStartPos+"-"; q1H=/[a  
httpConnection.setRequestProperty("RANGE",sProperty); 53B.2 4Tm  
Utility.log(sProperty); S[v Rw]*  
JW=uK$sO  
Yt -W1vl  
InputStream input = httpConnection.getInputStream(); @4;&hP2Z:  
//logResponseHead(httpConnection); @gNpJB]V  
~eDI$IO  
:Df)"~/mO+  
byte[] b = new byte[1024]; ^w>&?A'!  
int nRead; F&xv z2G  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) aSUsyOe  
{ =(%*LY!Xc  
nStartPos += fileAccessI.write(b,0,nRead); cn$5:%IK  
//if(nThreadID == 1) S#k{e72 *  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \I;cZ>{u"}  
} B$ui:R/ t  
1YFeVMc  
D-6  
Utility.log("Thread " + nThreadID + " is over!"); i<mevL  
bDownOver = true;  ozU2  
//nPos = fileAccessI.write (b,0,nRead); {B3(HiC  
} *|oPxQCtK  
catch(Exception e){e.printStackTrace ();} d<#p %$A4  
} 7{-@}j`  
} _ \l HI  
ZPl PN;J^1  
\*uugw,\y  
//打印回应的头信息 ha5e(Hj?  
public void logResponseHead(HttpURLConnection con) ]oEQ4  
{ p'}lN|"{O  
for(int i=1;;i++) L?HF'5o  
{ /_q#a h  
String header=con.getHeaderFieldKey(i); e8{^f]5  
if(header!=null) >60"p~t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); : W~f;k  
Utility.log(header+" : "+con.getHeaderField(header)); "qS!B.rt:  
else  ;1@C_5C  
break; ^sV|ck  
} KY g3U  
} OF8WDo`  
088C|  
^!}F%  
public void splitterStop() g5}lLKT  
{ D^u\l  
bStop = true; wu2:'y>n  
} N<liS3>  
'0RRFO  
f>niFPW"  
} I8k  
vU}: U)S  
#W|!fILL  
/* WYLX?x  
**FileAccess.java VjB*{,  
*//文件访问(定位,写) kwlC[G$j7  
package NetFox; | 3giZ{  
import java.io.*; C2G  |?=  
>S'>!w  
Fg=v6j4W  
public class FileAccessI implements Serializable{ TV=c,*TV  
K2HvI7$-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ZoxS*Xk  
RandomAccessFile oSavedFile; !BUi)mo  
long nPos; BI.V0@qZ  
A$@o'Q;he  
:Fw?{0  
public FileAccessI() throws IOException <HF-2?`  
{ bMmra.x4L  
this("",0); 9|=nV|R'6  
} lR@& Z6lw  
W 2<3C  
K/|  
public FileAccessI(String sName,long nPos) throws IOException .&iN(Bd  
{ v459},!P  
oSavedFile = new RandomAccessFile(sName,"rw"); Q]#Z9H  
this.nPos = nPos; 76u{!\Jo/{  
oSavedFile.seek(nPos); X$V|+lTk  
} -k{ Jp/-D  
Cs4hgb|  
tOH0IE c  
public synchronized int write(byte[] b,int nStart,int nLen) iyj3QLqE  
{ fY_%33_I$  
int n = -1; e+@xs n3  
try{ 9p`r7:  
oSavedFile.write(b,nStart,nLen); g 1@wf  
n = nLen; jNc<~{/  
} o&$hYy"<.L  
catch(IOException e) 2~FPw{]j  
{ gS$A   
e.printStackTrace (); _- %d9@x  
} f xtxu?A>  
G{o+R]Us  
w>vH8f  
return n; d#\W hRE  
} WZ?!!   
x?L hq2  
5pJ*1pfeo  
} hYb9`0G"2  
d(S}NH  
dJl^ADX[@  
/* Dp^/gL=  
**SiteInfoBean.java O&'/J8  
*/ lLCdmxbT  
package NetFox; w^o }E)O  
-0 0}if7  
4;*f1_;f~  
public class SiteInfoBean { 0{R/<N  
VXIQw' Cq  
mP-2s;q  
private String sSiteURL; //Site's URL yVS\Q,:J9  
private String sFilePath; //Saved File's Path Y8ehmz|g]J  
private String sFileName; //Saved File's Name ez*jjm  
private int nSplitter; //Count of Splited Downloading File M!{'ED  
jTSOnF}C~+  
Uix{"  
public SiteInfoBean() ^\wl2  
{//nSplitter的缺省值为5 T=\!2gt  
//default value of nSplitter is 5  r(`nt-o@  
this("","","",5); I]uhi{\C  
} R]Qp Mj%o  
@ yxt($G  
;[6&0! N\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )+Y&4Qu  
{ d^84jf.U  
sSiteURL= sURL; n`L,]dco  
sFilePath = sPath; G|9B )`S  
sFileName = sName; r4;Bu<PQN1  
this.nSplitter = nSpiltter; }*kJ-q&0  
.nZ3kT`  
k dU! kj  
} C6@t  
X+ f9q0  
o&-L0]i|  
public String getSSiteURL() =B(mIx;m  
{ Oif,|:  
return sSiteURL; JJf<*j^G  
} [7W(NeMk  
n33kb/q*  
s AE9<(g&@  
public void setSSiteURL(String value) <_:zI r,  
{ A=`* r*  
sSiteURL = value; F?4Sz#  
} 3Gd0E;3sk~  
_#'9kx|)  
+1@AGJU3  
public String getSFilePath() b5 Q NEi  
{ D ,M@8 h,  
return sFilePath; KQ)T(mIqp  
} #T% zfcUj  
6?SFNDQ"C  
Qpu3(`d<  
public void setSFilePath(String value) mJMq{6;  
{ frH)_YJ%  
sFilePath = value; DuNcX$%%  
} <lo`q<q  
h4 vm{ho  
u~'OcO  
public String getSFileName() tWk{1IL  
{ d=F-L  
return sFileName; n,nisS  
} CW0UMPE5  
~`Sle xK|}  
detLjlE  
public void setSFileName(String value) Kbas-</Si  
{ `P.CNYR<J  
sFileName = value; D#v?gPo4  
} cyMs(21  
d8:C3R  
t _\MAK  
public int getNSplitter() M 9"-WIG@h  
{ re uYTH  
return nSplitter; ;0j*>fb\q7  
} Ae3,^  
c]v +  
h7?.2Q&S  
public void setNSplitter(int nCount) r}EM4\r  
{ HV\"T(8 9  
nSplitter = nCount; FpzP #;  
} EcW1;wH  
} (C`@a/q  
EUZq$@uWL  
l* Y[^'  
/* evOb  
**Utility.java qGa<@ b  
*/ -f.R#J$2  
package NetFox; *<k&#D"m  
<E}N=J'uJ  
1S*P"8N}0h  
public class Utility { wOcg4HlW  
g7Z9F[d  
Wp4K6x  
public Utility()  UTX](:TC  
{ CB]l[hM$  
pqq?*\W&[v  
oCA(FQ6  
} KZ3B~#oQ  
4\1;A`2%0  
//线程睡眠 g*c\'~f;  
public static void sleep(int nSecond) HXV73rDA  
{ KJJb^6P48W  
try{ ST8/ ;S#c  
Thread.sleep(nSecond); @] "9EW 0  
} 9-iB?a7{.  
catch(Exception e) E!~2\qKT  
{ &b6@_C9  
e.printStackTrace (); I \%Lb z  
} b`|MK4M(  
} Tl7:}X<?  
MMr7,?,$  
//日志 hYv 6-5_  
public static void log(String sMsg) <J }9.k  
{ K2MNaB   
System.err.println(sMsg); iE gM ~  
} -+_aL4.  
-Fc#  
Y6%OV?}v!  
public static void log(int sMsg) @ h`Zn1;  
{ H_=[~mJ  
System.err.println(sMsg); NEou2y+}  
} O*/-I pM  
} GJt9hDM$0  
3N*C]  
NE%yv,B  
/* L{,7(C=  
**TestMethod.java x&/Syb  
*/ $,zM99  
package NetFox; ;xtb2c8HT  
L?C~ qS2g  
uvv-lAbjw  
public class TestMethod { >upUY(3&  
RkP|_Bf8)  
$5CY<,f  
public TestMethod() [K@!JY  
{ ///xx/weblogic60b2_win.exe ~)IJE+e>}  
try{ WJ4UJdf'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); UkbQ'P+oS  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); >37}JUG  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {ZEXlNPww  
fileFetch.start(); Dlf=N$BL7d  
} 5 ^J8<s@_  
catch(Exception e){e.printStackTrace ();} $<% nt  
NWwtq&pz2  
#I~dv{RX  
} by<@Zwtf  
HtYR 0J  
4m!3P"$  
public static void main(String[] args) $<e .]`R  
{ %vYlu%c<  
new TestMethod(); #&KE_ n  
} Y'*h_K  
} N_[ Q.HD"  
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