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http断点续传简单实现(java)

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/* > voUh;L  
**SiteFileFetch.java %%3ugD5i!  
*/ /y-P) 3_  
package NetFox; X:!%"K%}  
import java.io.*; "xO`&a{  
import java.net.*; #/1Bam6  
DV.MvFV  
:?^(&3;  
public class SiteFileFetch extends Thread { ~\kRW6  
9GGBJTk-  
&#)3v8  
SiteInfoBean siteInfoBean = null; //文件信息Bean dZYS5_wr  
long[] nStartPos; //开始位置 -+4$W{OK*0  
long[] nEndPos; //结束位置 0loC^\f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \m\.+q]  
long nFileLength; //文件长度 ?IWLl  
boolean bFirst = true; //是否第一次取文件 L NE]#8ue  
boolean bStop = false; //停止标志 {&4qknPd%  
File tmpFile; //文件下载的临时信息 $Z,+aLmb  
DataOutputStream output; //输出到文件的输出流 mee-Qq:}  
UU !I@  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) !#?tA/t@  
public SiteFileFetch(SiteInfoBean bean) throws IOException +tA rH C]  
{ 9wwvh'T&NK  
siteInfoBean = bean; ,onv `  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~KNxAxyVi  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3&zmy'b*:  
if(tmpFile.exists ()) f2Slsl;  
{   C[Fh^  
bFirst = false; zZ wD)p?_g  
read_nPos(); CkflEmfe  
} #&/*ll)  
else iN)@Cu7  
{ Gmc"3L  
nStartPos = new long[bean.getNSplitter()]; yZ  P+  
nEndPos = new long[bean.getNSplitter()]; |_rj 12.xo  
} q<UqGj7#   
S xgY q  
^:q(ksssY  
"8rP?B(  
} ILpB:g  
IrVeP&KM+  
!bY{T#i)k  
public void run() N" 8o0>  
{ aL`pvsnF  
//获得文件长度 t3WlVUtq3  
//分割文件 $ OR>JnV  
//实例FileSplitterFetch f9 rToH  
//启动FileSplitterFetch线程 ywdNwNJ  
//等待子线程返回 \\T I4A^#  
try{ p 2i5/Ly  
if(bFirst) b9vKux  
{ (=\P|iv  
nFileLength = getFileSize(); C6Mb(&  
if(nFileLength == -1) W=b5{ 6  
{  {jl4`  
System.err.println("File Length is not known!"); ^aC[Z P:  
} HC0puLt_  
else if(nFileLength == -2) jgYiuM3c\  
{ _]4cY%s  
System.err.println("File is not access!"); WV6vM()#!C  
} vrbS-Z<S9  
else wx1uduT)  
{ v#X? KqD  
for(int i=0;i<nStartPos.length;i++) sM4wh_lO  
{ 1TVTP2&Rd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); BAPi<U'D  
} "-Ns1A8  
for(int i=0;i<nEndPos.length-1;i++) l nZ=< T  
{ vKW%l  
nEndPos = nStartPos[i+1]; ;L`'xFo>>  
} m&x0,8  
nEndPos[nEndPos.length-1] = nFileLength; C +IXP  
} 'D-imLV<<  
} RDZq(rKc  
m ;KP  
uaGg8  
//启动子线程 ^\CQWgY(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; (&B & V  
for(int i=0;i<nStartPos.length;i++) b)V[d8IA  
{ MHbRG_zW  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Rl)/[T  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), E*ic9Za8`h  
nStartPos,nEndPos,i); 9-@w(kMu  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _S[H:b$?  
fileSplitterFetch.start(); (u*]&yk  
} QL)UPf>Kp  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '5Y8 rv<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <wuP*vI "h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", f;b(W  
nEndPos = " + nFileLength); toCN{[  
// fileSplitterFetch[nPos.length-1].start(); >Kr,(8rA  
z(m*]kpL"  
U/ZbE?it>  
//等待子线程结束 }C'z$i( y  
//int count = 0; 6>"0H/y,  
//是否结束while循环 lDH0bBmd0  
boolean breakWhile = false; h!Ka\By8#  
a@7we=!  
qmK!d<4  
while(!bStop) "L ,FUo^&  
{ cVz.ac  
write_nPos(); W$3p,VTMmB  
Utility.sleep(500); ?T^$,1 -  
breakWhile = true; 6^zv:C%  
LJiMtqg  
USbiI %   
for(int i=0;i<nStartPos.length;i++) ctCfLlK  
{ )~5`A*Ku  
if(!fileSplitterFetch.bDownOver) $DMeUA\av  
{ #e#8I7P  
breakWhile = false; ;6]+/e7O  
break; *L^{p.K4  
} =tP|sYR]^  
} Ri,UHI4 W  
if(breakWhile) }r i"u;.R  
break; \Lc pl-;?  
5~sJ$5<,  
'UB<;6wy  
//count++; mr/^lnO  
//if(count>4) 1xx-}AIH#  
// siteStop(); jeW0;Cz J~  
} fer'2(G?W  
Zj}, VB*T  
X{ Nif G  
System.err.println("文件下载结束!"); "NJ!A  
} L*5&hPU  
catch(Exception e){e.printStackTrace ();} Og,,s{\  
} u'N'<(\k  
9 ROKueP  
L7KHs'c*  
//获得文件长度 ,mRN;|N  
public long getFileSize() qH-dT,`"{  
{ weu'<C   
int nFileLength = -1; bT>^% H3  
try{ l"MEX/   
URL url = new URL(siteInfoBean.getSSiteURL()); K=~h1qV:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b\^.5SEw  
httpConnection.setRequestProperty("User-Agent","NetFox"); /fD)/x  
r)b`3=  
4];NX  
int responseCode=httpConnection.getResponseCode(); h)YqC$A-s  
if(responseCode>=400) p<![JeV  
{ wRuJein#  
processErrorCode(responseCode); YsTfv1~z#  
return -2; //-2 represent access is error zX5p'8-  
} X&Mc NO6"  
sQ`8L+oY  
O<+C$J|  
String sHeader; c XY!b=9  
hsl Js^  
p%G\5.GcJL  
for(int i=1;;i++) ad"&c*m[  
{ PM_q"}-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Fc nR}TE  
//Utility.log(in.readLine()); Ck[Z(=b$$:  
sHeader=httpConnection.getHeaderFieldKey(i); 9@S icqx   
if(sHeader!=null) oACE:h9U  
{ <H 3}N!  
if(sHeader.equals("Content-Length")) :Ct} ||9/  
{ c\R! z&y~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9(H8MUF0{  
break; K_My4>~Il  
} 7tyn?t0n  
} nVYh1@yLy  
else G q:7d]c~T  
break; )`U T#5  
} sd=i!r)ya  
} gz$=\=%>RL  
catch(IOException e){e.printStackTrace ();} yP"_j&ef7  
catch(Exception e){e.printStackTrace ();} is`a_{5e=  
;/YSQt)rc>  
Cd (Ov5%  
Utility.log(nFileLength); Nl(Aa5:!  
21;n0E  
xXyzzr1[  
return nFileLength; jm*v0kNy  
} a @TAUJ,  
(57x5qP X  
`HHbQXB  
//保存下载信息(文件指针位置) G& ;W  
private void write_nPos() eR3!P8t  
{ ~=c#Ff =Z  
try{ 1&m08dZm5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); N/y.=]  
output.writeInt(nStartPos.length); 5v?6J#]2  
for(int i=0;i<nStartPos.length;i++) |_ ;-~bmb  
{ n,fUoS  
// output.writeLong(nPos); RJg# A`  
output.writeLong(fileSplitterFetch.nStartPos); n'R 8nn6^  
output.writeLong(fileSplitterFetch.nEndPos); V6Q[Y>84~a  
} $+rdzsf)+/  
output.close(); .Wb),  
} ,@2O_O`:  
catch(IOException e){e.printStackTrace ();} 2 OGg`1XX  
catch(Exception e){e.printStackTrace ();} aUJ&  
} q!FJP9x  
qg'm<[  
m@yaF: R  
//读取保存的下载信息(文件指针位置) KJ~f ~2;  
private void read_nPos() kiXa2Yn*(d  
{ Bg34YmZ  
try{ m2 OP=z@)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ot/Y?=j~  
int nCount = input.readInt(); 7$w:~VZ  
nStartPos = new long[nCount]; <;acWT?(  
nEndPos = new long[nCount]; 2Gx&ECa,  
for(int i=0;i<nStartPos.length;i++) #$#{QEh0}  
{ mDo]5 i<  
nStartPos = input.readLong(); T%ha2X=  
nEndPos = input.readLong(); / P{f#rV5  
} ZL@7Mr!e  
input.close(); )ll}hGS  
} R (hq Ba/V  
catch(IOException e){e.printStackTrace ();} M>'-P  
catch(Exception e){e.printStackTrace ();} lv{Qn~\y&  
} n2T vPt\  
8_ju.h[  
)+ S"`  
private void processErrorCode(int nErrorCode)  Kp!P/Q{  
{ E]+W^ VG  
System.err.println("Error Code : " + nErrorCode); Ot(EDa9}IJ  
} zf^!Zqn[8z  
!iZ*ZPu  
G*n5`N@>7  
//停止文件下载 9WHkw@<R+  
public void siteStop() |>p\*Dl}H  
{  g\n@(T$)  
bStop = true; }z[ O_S,X  
for(int i=0;i<nStartPos.length;i++) `< VoZ/v  
fileSplitterFetch.splitterStop(); YwKY3kL  
rj,Sk~0Q  
D3MuP p-v  
} Amz7j8zJ  
} =`{!" 6a  
//负责部分文件的抓取 S6K aw  
**FileSplitterFetch.java N>@AsI  
*/ F-2HE><+  
package NetFox; Oa*/jZjr  
A 8&%G8d  
r$*k-c9Bf  
import java.io.*; XD*$$`+#  
import java.net.*; d<#Xqc  
VP|9Cm=Fg  
T0Y=g n  
public class FileSplitterFetch extends Thread { 6 )Oe]{-  
{KODwP'~  
0Wk}d(f  
String sURL; //File URL d~YDg{H  
long nStartPos; //File Snippet Start Position O^ f[ ugs  
long nEndPos; //File Snippet End Position `qX'9e3VP+  
int nThreadID; //Thread's ID BEu9gu  
boolean bDownOver = false; //Downing is over 2\m+  
boolean bStop = false; //Stop identical g pO@xk$  
FileAccessI fileAccessI = null; //File Access interface !a?o9<V  
C[&L h_F\  
W"z!sf5U  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #{<Jm?sU  
{ 2,dG Rf  
this.sURL = sURL; .XS rLb?  
this.nStartPos = nStart; R1?g6. Mq  
this.nEndPos = nEnd; jtl7t59R  
nThreadID = id; lHZf'P_Wx  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 o#E z_D[  
} Pbz-I3+66  
?^k-)V  
a*=\-;HaZ  
public void run() dB< \X.   
{ y?Fh%%uNr  
while(nStartPos < nEndPos && !bStop) Z\TH=UA  
{ u5%.T0 P  
l6)*u[}E   
i1u & -#k  
try{ TB1 1crE  
URL url = new URL(sURL); eF:6k qg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~I2 IgEj>]  
httpConnection.setRequestProperty("User-Agent","NetFox"); |1;0q<Ka  
String sProperty = "bytes="+nStartPos+"-"; O8n\>pkI  
httpConnection.setRequestProperty("RANGE",sProperty); UB?a-jGZ K  
Utility.log(sProperty); 'ApWYt  
llQDZ}T  
e>"{nOY4  
InputStream input = httpConnection.getInputStream(); 0Ac]&N d`  
//logResponseHead(httpConnection); dH?;!sJ  
H@'Y>^z?  
C{+~x@  
byte[] b = new byte[1024]; |PTL!>ym2  
int nRead; /q(+r5k \  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #jK{)%}mA  
{ yQ6{-:`)  
nStartPos += fileAccessI.write(b,0,nRead); 9 /q4]%`  
//if(nThreadID == 1) ~M,nCG^4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /.Gx n0  
} _ ?=bW  
!P#lTyz  
${mHbqN  
Utility.log("Thread " + nThreadID + " is over!"); $wC]S4C  
bDownOver = true; N2=gSEY  
//nPos = fileAccessI.write (b,0,nRead); / ijj;9EB  
} oP_'0h0 X  
catch(Exception e){e.printStackTrace ();} e)>Z&e,3  
} SIzW3y[  
} a&4>xZU #  
ejD;lvf  
En-eG37 l  
//打印回应的头信息 =DvnfT<  
public void logResponseHead(HttpURLConnection con) sj Yg  
{ 3E:wyf)i"  
for(int i=1;;i++) A+NLo[swwu  
{ ,8EeSnI  
String header=con.getHeaderFieldKey(i); )7[>/2aGd  
if(header!=null) ka*VQXk*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); '2v,!G]^  
Utility.log(header+" : "+con.getHeaderField(header)); n%@xnB $ZX  
else ) T 3y,*  
break; d v"  
} x)nBy)<  
} lOcvRF  
 /dBQ*f5  
V#C[I~l  
public void splitterStop() t9W_ [_a9  
{ R&=Y7MfZ  
bStop = true; 44($a9oa2  
} !j( v-pQf"  
!9OAMHa*9  
6^}GXfJAc  
} e,|"9OK  
^cBA8 1  
x w]Zo<F  
/* /V-7u  
**FileAccess.java qEX59v  
*//文件访问(定位,写) }=;N3Q" #y  
package NetFox; hH`yQGZ  
import java.io.*; 5H;*Nj@  
<fWho%eOK  
9akCvY#Q  
public class FileAccessI implements Serializable{ ); 7csh%  
)xlNj$(x5n  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 c"77<Db$  
RandomAccessFile oSavedFile; __'Z0?.4#  
long nPos; F2OU[Z,-]  
*cq#>rN  
'xvV;bi  
public FileAccessI() throws IOException FL"IPX;S  
{ 1m|1eAGS{  
this("",0); PBR+NHrZ  
} H Viu7kue`  
1K4LEg a`  
hFyN|Dqhds  
public FileAccessI(String sName,long nPos) throws IOException }DY^a'wJ-  
{ boJQ3Xc  
oSavedFile = new RandomAccessFile(sName,"rw"); NS mo(c >5  
this.nPos = nPos; ~iyd p  
oSavedFile.seek(nPos); N@Bqe{r6j  
} YtxBkKiJ2V  
>0T0K`o  
}0}J  
public synchronized int write(byte[] b,int nStart,int nLen) : :e=6i  
{ V]`V3cy1+3  
int n = -1; !V7VM_}@Y  
try{ ^7~=+0cF]  
oSavedFile.write(b,nStart,nLen); mJ !}!~:  
n = nLen; A\.k['!  
} <@ (HQuL#  
catch(IOException e) JwxI8Pi*y  
{ >")%4@  
e.printStackTrace (); a}El!7RO0  
} (;V]3CtU*  
X7Cou6r  
%[Ia#0'Y@  
return n; ~u/Enl7\-  
}  @X  
at ]Lz_\  
_f{'&YhUU  
} GDZe6*  
]J?5qR:xCy  
4,wdIdSm4  
/* (gs"2  
**SiteInfoBean.java gP^'4>Jr  
*/ >x (^g~i  
package NetFox; mzfj!0zR*  
Q3_ia 5 `O  
,r:. 3.  
public class SiteInfoBean { ([`-*Hy  
W5EB+b49KM  
3,S5>~R=  
private String sSiteURL; //Site's URL `{ou4H\  
private String sFilePath; //Saved File's Path \[ +ZKj:  
private String sFileName; //Saved File's Name 80c\O-{  
private int nSplitter; //Count of Splited Downloading File akrEZ7A  
N;;!ObVHnP  
Z!^iPB0~D  
public SiteInfoBean() d+[hB4!l2  
{//nSplitter的缺省值为5 YmNBtGhT  
//default value of nSplitter is 5 W(a=ev2sa  
this("","","",5); O9:vPbn  
} F~)xZN3=  
qf(!3  
G{YJ(6etZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Bn-%).-ED  
{ Zb<DgJ=3  
sSiteURL= sURL; SN\;&(?G  
sFilePath = sPath; =DcKHL(m  
sFileName = sName; P;mmK&&  
this.nSplitter = nSpiltter; )7*Apy==x  
JG0TbM1(Bt  
9Z6O{ >  
}  Z:u7`%  
AIN_.=]"?  
: R.,<DQM  
public String getSSiteURL() %~}9#0h)  
{ 7?Xfge%\  
return sSiteURL; e9o(hL  
} Cq}LKiu  
!NZFo S~  
pU<->d;->  
public void setSSiteURL(String value) ;UArDwH  
{ M5[AA/@  
sSiteURL = value; "72 _Sw  
} ^#vWdOlt  
C(xdiQJh  
h9 [ov)  
public String getSFilePath() ZYc)_Og  
{ lH T?  
return sFilePath; li$(oA2  
} G'#a&6  
KokmylHu  
,^`+mP  
public void setSFilePath(String value) =cX &H  
{ oju4.1  
sFilePath = value; P0 hC4Sxf  
} 7:9WiN5b  
"qMd%RP  
Y GvtG U-  
public String getSFileName() }+,1G!? z  
{ )LKutN?tBy  
return sFileName; Y{f;qbEQH'  
} s-3vp   
mst-:F[h  
2PAo tD4+I  
public void setSFileName(String value) C[|jJ9VE,  
{ 6psK2d0  
sFileName = value; }gGcYRT  
} [;83 IoU}  
`>g: :  
P)7SK&]r;=  
public int getNSplitter() cOxF.(L  
{ gR?=z}`@p  
return nSplitter; 305()  
} jaFBz&P/#  
f*aYS  
b: +.Y$%F-  
public void setNSplitter(int nCount) "  q0lh  
{ j2k,)MHu!x  
nSplitter = nCount; ||0mfb  
} SB:-zQ5  
} kOs_]  
M(jSv  
[qI, $ +  
/* bmGIxBRq  
**Utility.java o/)]z  
*/ QZYD;&iY&  
package NetFox; ")i4w{_y  
.?@$Rd2@W  
j_j~BXhIS  
public class Utility { i%:oO KI  
/MosE,7l  
}c:s+P+/  
public Utility() )xoIH{  
{ Kj;Q;Ii  
?FA} ;?v  
#JWW ;M6F  
} Nw/4z$].J  
=NQDxt}  
//线程睡眠 @9~6+BZOq  
public static void sleep(int nSecond) g-bHf]'  
{ F $^RM3  
try{  &)T5V  
Thread.sleep(nSecond); J)"2^?!&B  
} l*e*jA_>:7  
catch(Exception e) a[ 1^)=/DM  
{ 5.q2<a :  
e.printStackTrace (); |p-, B>p!  
} wJNiw)C  
} -2{NI.-Xd  
9!NL<}]{  
//日志 %7x x"$P:R  
public static void log(String sMsg) g~rZ=  
{ :54ik,l  
System.err.println(sMsg); 9l]+ rs +  
} Hca vA{H  
}i^]uW*h  
tMR&>hM  
public static void log(int sMsg) &'TZU"_  
{ m6a`OkP  
System.err.println(sMsg); *GH` u*C_  
} f(6`5/C  
} w/IYQC\v  
04D>h0yFf  
'=Nb`n3%  
/* mCb(B48]%X  
**TestMethod.java %iPWg  
*/ nQy.?*X  
package NetFox; idPx! fe  
A,Wwt [Qw  
J<'[P$D  
public class TestMethod { Ub2t7MU  
MzM"r"u  
U0 nSI  
public TestMethod() -GCC  
{ ///xx/weblogic60b2_win.exe MxQhkY-=  
try{ Ye% e!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ikX"f?Q;S2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); BiT #bg  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @.0>gmY;:  
fileFetch.start();  Fku~'30  
} Z-z^0QO  
catch(Exception e){e.printStackTrace ();} (~q.YJ'  
r'/&{?Je/  
AJ}QS?p8s  
} YcOPqvQ  
O]3$$uI=QE  
EmNJ_xY  
public static void main(String[] args) 6Ri+DPf:  
{ LM\H%=*L  
new TestMethod(); [ R  
} b 5<&hN4g  
} 8eq*q   
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