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http断点续传简单实现(java)

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/* v NeCpf  
**SiteFileFetch.java m "M("%  
*/ A 5+rd{k/  
package NetFox; " beQZG  
import java.io.*; PT^c^{V  
import java.net.*; RC^9HuR&  
Zo}y(N1K}  
Bcjx>#3?L  
public class SiteFileFetch extends Thread { )' hH^(Yu  
D!oc>K$B  
R@*O!bD  
SiteInfoBean siteInfoBean = null; //文件信息Bean TP}h~8 /;  
long[] nStartPos; //开始位置 8 :o<ry  
long[] nEndPos; //结束位置 xEltwuDd?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 c=[O `/f  
long nFileLength; //文件长度 4:sjH.u<  
boolean bFirst = true; //是否第一次取文件 x%<  
boolean bStop = false; //停止标志 .p ls!  
File tmpFile; //文件下载的临时信息 t'~/$=9}  
DataOutputStream output; //输出到文件的输出流 M@(^AK{mU  
Pe_!?:vF  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) /{{UP-  
public SiteFileFetch(SiteInfoBean bean) throws IOException `Bw9O%]-S  
{ enTW0U}  
siteInfoBean = bean; 5PIZh<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]u-02g  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); z**hD2R!  
if(tmpFile.exists ()) oR~e#<$;  
{ 97,rE$bC  
bFirst = false; 20TCG0% x  
read_nPos(); Otz E:qe  
} -L3|&O_  
else D-U<u@A4  
{ ,=~z6[  
nStartPos = new long[bean.getNSplitter()]; ai'4_  
nEndPos = new long[bean.getNSplitter()]; {&[9iIf  
} j.i#*tN//  
BT_tOEL#  
'&FjW-`" G  
7Mx6  
} +"ueq  
cM&2SRBZ  
M('d-Q{B7L  
public void run() `Ci4YDaz;k  
{ fRvAKz|rL  
//获得文件长度 kL90&nP   
//分割文件 #RMI&[M  
//实例FileSplitterFetch 2`a q**}  
//启动FileSplitterFetch线程 $ C0TD7=  
//等待子线程返回 =1oNZKBP  
try{ `T2<<<  
if(bFirst) J R PSvP\  
{ +y#T?!jQYj  
nFileLength = getFileSize(); O%f8I'u$  
if(nFileLength == -1) [,~TaP}m  
{ UzKFf&-:;K  
System.err.println("File Length is not known!"); .la&P,j_L  
} `aqrSH5^h  
else if(nFileLength == -2) MqKye8h9f  
{ {S<>&?XB  
System.err.println("File is not access!"); 8yW oPm<A  
} %>WbmpIyc  
else Vh<A2u3&  
{ + q''y  
for(int i=0;i<nStartPos.length;i++) kz q29S  
{ '(#g1H3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); S:8OQI  
} v8I{XU@%  
for(int i=0;i<nEndPos.length-1;i++) ibdO*E  
{ '+*-s7o{  
nEndPos = nStartPos[i+1]; O!Wd5Y  
} Q0{z).&\(e  
nEndPos[nEndPos.length-1] = nFileLength; tJ=di5&  
} . -"E^f  
} (shK  
~"!a9GZ  
@-#T5?  
//启动子线程 O4No0xeWo  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; R< zG^m  
for(int i=0;i<nStartPos.length;i++) `!G7k  
{ ^ie^VY($  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M8@_Uj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *OdX u&5  
nStartPos,nEndPos,i); g6sjc,`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); bQa oMZB  
fileSplitterFetch.start(); P|^$kK  
} fj 4^VXD  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), n~Szf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ACjf\4Q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", GIv){[i  
nEndPos = " + nFileLength); ]v5-~E!  
// fileSplitterFetch[nPos.length-1].start(); Y'Z+, CNf  
HXJ9xkrr  
-U>7 H`5  
//等待子线程结束 (tl}q3U  
//int count = 0; rwpgBl  
//是否结束while循环 0]x;n+G[q  
boolean breakWhile = false; >&H~nGP.  
t#<KxwhcN  
hN(L@0)  
while(!bStop) Z,WW]Y,$  
{ {@r*+~C3  
write_nPos(); :w?7j_p#  
Utility.sleep(500); WwW^[k (X  
breakWhile = true; }`9`JmNM  
C$#W{2x%6  
16@);Ot  
for(int i=0;i<nStartPos.length;i++) "A]Y~iQ  
{ ^C9x.4I$)  
if(!fileSplitterFetch.bDownOver) G5{Ot>;*%  
{ oA~4p(  
breakWhile = false; `W[+%b  
break; XLTD;[jO  
} &.*uc|{  
} B50 [O!  
if(breakWhile) (BERY  
break; k_3j '  
qa}>i&uO  
CtT~0Y|  
//count++; ;o$;Z4:.D  
//if(count>4) MB* u-N0v  
// siteStop(); 4^O w^7N?  
} HR3_@^<7  
v3JPE])/  
F$*3@Y  
System.err.println("文件下载结束!"); j;2<-{  
} n6d^>s9J  
catch(Exception e){e.printStackTrace ();} *\LyNL(  
} Y&,rTa  
m{&w{3pQk  
-NDi5i\  
//获得文件长度 $o^e:Y , a  
public long getFileSize() lEfBe)7+  
{ i=8UBryr'e  
int nFileLength = -1; -3mgza  
try{ 6.Bh3p  
URL url = new URL(siteInfoBean.getSSiteURL()); @8"18HEp#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a{`"68  
httpConnection.setRequestProperty("User-Agent","NetFox"); s#lto0b"8  
F14(;'Az  
4uX(_5#j  
int responseCode=httpConnection.getResponseCode(); 93I'cWN  
if(responseCode>=400) 55hyV{L%  
{ GOW"o"S  
processErrorCode(responseCode); p`GWhI?  
return -2; //-2 represent access is error ek[kq[U9  
} Igjr~@ #  
Ky&KF0  
uu>lDvR*  
String sHeader; (/fT]6(  
)C}KR`"  
\Hs|$   
for(int i=1;;i++) 5OB]x?4]  
{ RqGVp?   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); '\L0xw4  
//Utility.log(in.readLine()); Wg(bD,  
sHeader=httpConnection.getHeaderFieldKey(i); pruWO'b`  
if(sHeader!=null)  N ?+eWY  
{ v[D&L_  
if(sHeader.equals("Content-Length")) _>v0R'  
{ 5w-JPjH  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); zKJ. Tj W  
break; ih!~G5Xi9i  
} 1#D<ZN  
} A7(M,4`6  
else QUPf *3Oy  
break; hb! ln7  
} C*O ,rm}  
} vfXJYw+6_  
catch(IOException e){e.printStackTrace ();} a*Jn#Mx<M  
catch(Exception e){e.printStackTrace ();} [` 'd#pR  
]-KV0H  
@,YlmX}  
Utility.log(nFileLength); f N0bIE Y  
BVAr&cu  
RH=$h! 5  
return nFileLength; va>"#;37  
} L *{QjH  
b8cVnP  
( H[  
//保存下载信息(文件指针位置) Q)+Y}  
private void write_nPos() \[k% )_  
{ o4'Wr  
try{ (+x]##Q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); \=8=wQv  
output.writeInt(nStartPos.length); #gI&lO*\gr  
for(int i=0;i<nStartPos.length;i++) <Cr8V'c  
{ L"^.0*X/d  
// output.writeLong(nPos); ~T&% VvI  
output.writeLong(fileSplitterFetch.nStartPos); (!ZV9S  
output.writeLong(fileSplitterFetch.nEndPos); L1F###c  
} RnSm]}?  
output.close(); {Ve D@  
} SJOmeN}4)  
catch(IOException e){e.printStackTrace ();} *pK lA&_  
catch(Exception e){e.printStackTrace ();} Oh-Fp-v87  
} H%cp^G  
$vqU|]J`  
2R] XH 0   
//读取保存的下载信息(文件指针位置) YnD#p[Wo^  
private void read_nPos() 2) ?  
{ x?rbgsB5&  
try{ &_YtY47  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L^jaBl  
int nCount = input.readInt(); Dh?vU~v(6  
nStartPos = new long[nCount]; W[GQ[h  
nEndPos = new long[nCount]; _^b@>C>O  
for(int i=0;i<nStartPos.length;i++) +]_nbWL(%  
{ K{N%kk%F  
nStartPos = input.readLong(); pEkOSG  
nEndPos = input.readLong(); E+Im~=m$  
} _lNC<7+#h  
input.close(); +.wT 9kFcc  
} ]DU61Z"v?b  
catch(IOException e){e.printStackTrace ();} S{ey@ X(  
catch(Exception e){e.printStackTrace ();} :Dt\:`(r'  
} RZe#|k+ 8  
HrDTn&/  
363cuRP  
private void processErrorCode(int nErrorCode) CvP`2S\  
{ O!yakU+  
System.err.println("Error Code : " + nErrorCode); r/^tzH's  
} 0w'|d@*wV  
\.kTe<.:_  
p; F2z;#  
//停止文件下载 w'|&5cS  
public void siteStop() +!Q!m 3/I  
{ E;xMPK$  
bStop = true; '1]+8E `Z  
for(int i=0;i<nStartPos.length;i++) l3BD <PB2S  
fileSplitterFetch.splitterStop(); 2DUr7r M  
[h^f%  
\ U Ax(;  
} 6{ C Fe|XN  
} l`G(O$ct  
//负责部分文件的抓取 =p5?+3" @  
**FileSplitterFetch.java erXy>H[;  
*/ Esb ?U|F4  
package NetFox; y%2%^wF  
D7M0NEY  
^t`f1rGR  
import java.io.*; T7^ulG1'  
import java.net.*;  YN4"O>  
\m%J`{Mt  
`(!W s\:  
public class FileSplitterFetch extends Thread { O1|B3M[P  
G&.d)NfE  
jT{f<P0  
String sURL; //File URL Lr wINVa  
long nStartPos; //File Snippet Start Position wInY7u Bd!  
long nEndPos; //File Snippet End Position Is<x31R  
int nThreadID; //Thread's ID >1m)%zt  
boolean bDownOver = false; //Downing is over xnT3^ #-h  
boolean bStop = false; //Stop identical " \`BPN  
FileAccessI fileAccessI = null; //File Access interface g)X7FxS,z  
HgYc@P*b  
@l)\?IEF@f  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (rAiDRQ[  
{ )\D2\1e(c  
this.sURL = sURL; uXjoGcW  
this.nStartPos = nStart; i^/ eN  
this.nEndPos = nEnd; L7s>su|c(  
nThreadID = id; tF<^9stM  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 #"hJpyW 4V  
} 7[4_+Q:}  
^GE^Q\&D&  
=d}gv6v2S  
public void run() *Yj~]E0`1  
{ +:fqL  
while(nStartPos < nEndPos && !bStop) ESn6D@"  
{ p(~Y" H  
yI3Q|731)  
JL?Cnk$!  
try{ 45?*:)l:  
URL url = new URL(sURL); ||yXp2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &$<(D0  
httpConnection.setRequestProperty("User-Agent","NetFox"); gW'P`Oxw  
String sProperty = "bytes="+nStartPos+"-"; KbXbT  
httpConnection.setRequestProperty("RANGE",sProperty); dFd lB `L  
Utility.log(sProperty); $*YC7f  
u)tHOV>&  
N[0 xqQ  
InputStream input = httpConnection.getInputStream(); a3Z :C!|O'  
//logResponseHead(httpConnection); TNyK@~#m  
f#'8"ff*1  
|sA4:Aq  
byte[] b = new byte[1024]; UCe,2v%  
int nRead; c"sj)-_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) P#w}3^  
{ ub[""M?  
nStartPos += fileAccessI.write(b,0,nRead); <\E"clZI  
//if(nThreadID == 1) +8Of-ZUx  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m5X3{[a :  
} l#X=]xQf  
L@>^_p$  
\d `dV0X  
Utility.log("Thread " + nThreadID + " is over!"); #L_@s d  
bDownOver = true; 7bA4P*  
//nPos = fileAccessI.write (b,0,nRead); AF6d#Klog  
} dNOX&$/=  
catch(Exception e){e.printStackTrace ();} A Z4|&iT  
} N8,EI^W8Z  
} X!,#'&p&  
x1.3W j  
hq5NQi` %  
//打印回应的头信息 ' 9IP;  
public void logResponseHead(HttpURLConnection con) zY]Bu-S3  
{ CWE Ejl  
for(int i=1;;i++) 6W)xj6<@  
{ *eHA: A_I  
String header=con.getHeaderFieldKey(i); J ZVr&KZN  
if(header!=null) U(rr vNt:t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ix*BI9E  
Utility.log(header+" : "+con.getHeaderField(header)); [LJ705t  
else f %bc64N(  
break; DkDw>Nx<rs  
} H @_eFlT t  
} 4$0jz'  
A Oby*c  
A8 \U CG  
public void splitterStop() @`w'   
{ B.]qrS|  
bStop = true; 5u'TmLuKT  
} }s`jl` `PM  
P3+)pOE-SI  
aeG#: Ln+{  
} ML=hKwCA  
9 eSN+q  
t7{L[C$  
/* K)yCrEZ  
**FileAccess.java "WF( 6z#  
*//文件访问(定位,写) >{O[t2&  
package NetFox; l@,);w=_P  
import java.io.*; B]A 5n8<  
Z_iAn TT  
wm); aWP  
public class FileAccessI implements Serializable{ s,eld@  
>/7KL2*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2uvQf&,  
RandomAccessFile oSavedFile; s(1_:  
long nPos; F,' ^se4&  
ddUjs8VvJ  
`U {o:  
public FileAccessI() throws IOException {toyQ)C7  
{ :)KTZ  
this("",0); l(h;e&9x  
} "wT ~$I"  
cJU!zG  
p{A}p9sjx  
public FileAccessI(String sName,long nPos) throws IOException }4bB7,j  
{ ](B& l{V  
oSavedFile = new RandomAccessFile(sName,"rw"); 8gVxiFjo  
this.nPos = nPos; 5?V?  
oSavedFile.seek(nPos); B(4:_ j\2  
} Z]mM  
/E`l:&89)  
l%sp[uqcg  
public synchronized int write(byte[] b,int nStart,int nLen) {ED(O -W  
{ 5]4<!m  
int n = -1; s`8M%ZLu  
try{ 6 . +[ z  
oSavedFile.write(b,nStart,nLen); 2+T8Y,g  
n = nLen; n:5O9,umZ  
} ?=;e.qK=71  
catch(IOException e) es.\e.HK  
{ ,cGwtt(  
e.printStackTrace (); ,Az`6PW  
} Rxvd+8FF  
Ft%TnEp  
T+AlcOP  
return n; veYsctK~  
} 4b3F9  
W2r6jm!  
.LXh]I *  
} %{N$1ht^  
ch5`fm  
H6%!v1 u  
/* R,d70w (_  
**SiteInfoBean.java %=NM_5a}]  
*/ ooLnJ Y#  
package NetFox; `}k&HRn  
#a7Amh\nT  
} #\;np  
public class SiteInfoBean { E<zT  
v@$evmA  
'f=)pc#&g  
private String sSiteURL; //Site's URL Ckl7rpY+  
private String sFilePath; //Saved File's Path zCBtD_@  
private String sFileName; //Saved File's Name y~]I Vl"  
private int nSplitter; //Count of Splited Downloading File C>w9 {h  
1K? & J2  
!^>LOH>j  
public SiteInfoBean() LH3N}J({  
{//nSplitter的缺省值为5 }%o+1 <=  
//default value of nSplitter is 5 c:?#zX  
this("","","",5); %vf2||a$BS  
} v GR \GFm  
E&iWtwkz  
wZ]BY;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Z!]U&Ax`Z  
{ dbMu6Bm\G  
sSiteURL= sURL; BDRYip[Sa  
sFilePath = sPath; }Ke}rM<  
sFileName = sName; S1H47<)UF  
this.nSplitter = nSpiltter; zulf%aaL  
a O"nD_7  
h 0QYoDvbC  
} ctc`^#q  
Z!*8JaMT  
JGSk4  
public String getSSiteURL() }l]3m=)  
{ pU:C =hq4  
return sSiteURL; x;ICV%g/  
} K+h9bI/Sf  
(2O} B.6  
@Q$ /eL  
public void setSSiteURL(String value) r3c\;Ra7  
{ MuFU?3ovG*  
sSiteURL = value; Ew?/@KAV\  
} Z5*(W;;  
}GoOE=rhY  
P[#WHbn  
public String getSFilePath() GqIvvnw@f  
{ _pH6uuB  
return sFilePath; A5.'h<  
} (. quX@w"m  
,rH)}C<Q+  
&-8-xw#.  
public void setSFilePath(String value) ~P]HG;$?n  
{ -h G 9  
sFilePath = value; F)E7(Un`8  
} +%Bf y4F6  
WB=<W#?w7%  
?G>5 D`V  
public String getSFileName() nIT^'  
{ Kc9mI>uH  
return sFileName; 4ye`;hXy  
} ?(,5eg  
e&H<lT  
/SqFP L]  
public void setSFileName(String value) @KW+?maW  
{ S,`Sq8H  
sFileName = value; +3o)L?:g  
} F"m}mf  
Z|Lh^G  
hBfzU\*0H  
public int getNSplitter() k9_VhR|!  
{  ,3@15j  
return nSplitter; [#Nx>RY  
} LG&Q>pt.  
:S+U}Sm[  
E9Xk8w'+  
public void setNSplitter(int nCount) G8(i).Q  
{ soqNzdTB2  
nSplitter = nCount; @8<uAu%  
} E!}-qbH^  
} Z'EO   
qs c-e,rl  
se n{f^U  
/* +{Jf]"KD  
**Utility.java >e$^# \D  
*/ h4B#T'b  
package NetFox; Ji}IV  
(y+5d00  
li_pM!dWU_  
public class Utility { [>J~M!yu:r  
{ZsWZJ!  
8F\Msx  
public Utility() 3R=3\;  
{ |L_g/e1A3  
cdtzf:#q  
HyX4ob[X  
} eR* ]<0=  
#`#aSqGmc  
//线程睡眠 dW^_tzfF7  
public static void sleep(int nSecond) oIL+@}u7  
{ qiKtR  
try{ 5.K$ X$+7}  
Thread.sleep(nSecond); G}dOx}kT  
} Lq $4.l[j  
catch(Exception e) 2W:?#h3  
{ }b ]y 0"  
e.printStackTrace (); kJ<Xq   
} f/[?5M[  
} ;AL@<,8  
tCCi|*P G  
//日志 @#--dOWYR  
public static void log(String sMsg) agxSb^ 8tF  
{ L^al1T  
System.err.println(sMsg); H'h4@S  
} =3v 1]7 X  
UVBw;V  
W$MEbf%1  
public static void log(int sMsg) iQ}sp64  
{ seV;f^-hR  
System.err.println(sMsg); &CeF^   
} :: 72~'tw  
} >yT@?!/Q>'  
zm3MOH^a  
~lalc ^  
/* < ,cIc]eX  
**TestMethod.java "1`i]Y\'  
*/ M Xt +  
package NetFox; ]S2[eS  
gS<{ekN  
pS@VLXZP  
public class TestMethod { gK#fuQ$hH  
x< y[na  
fJ"~XTN}T  
public TestMethod() L+ETMk0  
{ ///xx/weblogic60b2_win.exe gZ >orZL'  
try{ w4MMo  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F']%q 0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U;Y}2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); aj'8;E+  
fileFetch.start(); D%Jc?6/I#3  
} Pc; 14M  
catch(Exception e){e.printStackTrace ();} ' /<b[  
[qD<U%Hi  
FQ~ead36C  
} iN/!k.ybW}  
[BR}4(7  
Qbt>}?-  
public static void main(String[] args) ~Ow23N  
{ rKs WS~U  
new TestMethod(); ?O>JtEz~lQ  
} L\?g/l+k  
} W;g+R-  
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