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http断点续传简单实现(java)

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/* 7AwV4r*:  
**SiteFileFetch.java W|@7I@@$"  
*/ s5/5>a V  
package NetFox; ;+v5li  
import java.io.*; Vb{5-v ;a  
import java.net.*; 1{6BU!  
% 8c <C  
V11(EZJ/j  
public class SiteFileFetch extends Thread { ++O L&n  
OJ#eh w<  
j,<3[  
SiteInfoBean siteInfoBean = null; //文件信息Bean W,sU5sjA  
long[] nStartPos; //开始位置 #'`!*VI  
long[] nEndPos; //结束位置 MZYh44  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 D#%aow'(7  
long nFileLength; //文件长度 JFAmND;+  
boolean bFirst = true; //是否第一次取文件 5\\#kjjx  
boolean bStop = false; //停止标志 mjgwU8'![  
File tmpFile; //文件下载的临时信息 7D'-^#S5  
DataOutputStream output; //输出到文件的输出流 /#mq*kNIM6  
mCM7FFl I  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) b1+6I_u.  
public SiteFileFetch(SiteInfoBean bean) throws IOException H~Z$pk%  
{ qY,z,o AF  
siteInfoBean = bean; b\6 )whh  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .<xzf4C  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &[u>^VO8  
if(tmpFile.exists ()) :LE0_ .  
{ lKVy{X 3]*  
bFirst = false; j@chSk"K  
read_nPos(); ~kDR9s7  
} '8%pEl^  
else JA]TO (x  
{ 0!4;."S  
nStartPos = new long[bean.getNSplitter()]; G.j  R  
nEndPos = new long[bean.getNSplitter()]; S8=Am7D]1  
} $ghAC  
V[9#+l~#  
* SAYli+@  
 Om%HrT  
} 9NUft8QB  
\R"}=7  
'K|Jg.2  
public void run() k8>(-W"A  
{ }s*H| z  
//获得文件长度 VSm[80iR0  
//分割文件 8]SJ=c"}Xf  
//实例FileSplitterFetch $? 'JePC  
//启动FileSplitterFetch线程 '*4>&V.yX  
//等待子线程返回  Iw07P2  
try{ @B.;V=8wJ  
if(bFirst) Tbf@qid e  
{ 8(AI|"A"-  
nFileLength = getFileSize(); | aAu 4   
if(nFileLength == -1) }Iyr u3M][  
{ j@w+>h  
System.err.println("File Length is not known!"); 3HtLD5%Q  
} ?(C(9vO  
else if(nFileLength == -2) ioIOyj  
{ Drn{ucIs  
System.err.println("File is not access!"); Kmk}Yz  
} Z`_`^ \"  
else Fe:M'.  
{ Cx N]fo  
for(int i=0;i<nStartPos.length;i++) G,jv Mb`+  
{ w)Rtt 9  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |_<'q h  
} d3nx"=Cy0I  
for(int i=0;i<nEndPos.length-1;i++) t=-t xnlr<  
{ nqp:nw  
nEndPos = nStartPos[i+1]; /mdPYV  
} jCJbmEfo9@  
nEndPos[nEndPos.length-1] = nFileLength; <5 Ye')+  
} FWi c/7  
} g&79?h4UXQ  
q5Bj0r[/o  
,5Vc  
//启动子线程 \IL;}D{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fPW|)e"  
for(int i=0;i<nStartPos.length;i++) ~RdD6V  
{ '7'*+sgi$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Mx-? &  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), fG *1A\t]  
nStartPos,nEndPos,i); P4\{be>e  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "PFczoRZ  
fileSplitterFetch.start(); >M}\_c=  
} | c:E)S\  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R04%;p:k#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1);  9S<87sO  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", FJ/>=2^B  
nEndPos = " + nFileLength); xH,D bAC;  
// fileSplitterFetch[nPos.length-1].start(); 2&e2/KEWR  
RFsd/K;Zp  
[RAzKzC\M  
//等待子线程结束 %VV\biO]  
//int count = 0; rNi]|)-ET  
//是否结束while循环 4$5d*7  
boolean breakWhile = false; t:NYsL  
2 }9of[  
(31ia"i%  
while(!bStop) :Dh\  
{ j{U#g8  
write_nPos(); LnwI 7uvq  
Utility.sleep(500); :,<G6"i  
breakWhile = true; sI M^e  
S!LLC{  
|b BA0.yS  
for(int i=0;i<nStartPos.length;i++) 4qd =]i  
{ -\6";_Y  
if(!fileSplitterFetch.bDownOver)  |UudP?E  
{ $0kuR!U.N  
breakWhile = false; [N35.O6P6u  
break; 5s5GBJ?  
} gI~4A,  
} AQUl:0!  
if(breakWhile) \n&l  
break; iY|zv|;]=  
{r.KY  
'8k{\>  
//count++; '7Ad:em  
//if(count>4) ^R g=*L  
// siteStop(); ^| b]E  
} [!g$|   
iXF iFsb  
mJ'Q9x"  
System.err.println("文件下载结束!"); B-R& v8F  
} [Iwb7a0p  
catch(Exception e){e.printStackTrace ();} m L#%H(  
} xr;:gz!h  
""Ub^:ucD  
hc2AGeZr  
//获得文件长度 >}uDQwX8  
public long getFileSize() *y}<7R  
{ $] gwaJ:  
int nFileLength = -1; p)x*uqSd  
try{ @4O;dFOQ)  
URL url = new URL(siteInfoBean.getSSiteURL()); ZaNZUVBh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ! R b  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~x(1g;!^  
p aQ"[w  
Wl29xY}`{!  
int responseCode=httpConnection.getResponseCode(); We8n20wf<  
if(responseCode>=400) #`g..3ey  
{ E$4_.Z8sRw  
processErrorCode(responseCode); |v Gb,&3  
return -2; //-2 represent access is error M0B6v} ^H  
} LH:M`\(DL1  
\68x]q[  
Dc1tND$X3g  
String sHeader; OBCH%\;g  
<P%<EgOE  
q2$-U&  
for(int i=1;;i++) ]_hrYjX;  
{ GKk> ;X-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 96VJE,^h  
//Utility.log(in.readLine()); ~!Ar`= [  
sHeader=httpConnection.getHeaderFieldKey(i); 8et*q3D7`  
if(sHeader!=null) brdfj E8  
{ , GU|3  
if(sHeader.equals("Content-Length")) ~Z{IdE  
{ ( !THd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'Nqa=_<WW  
break; E7CeE6U  
} ,Ky-3p>  
} bV3az/U  
else I7S#vIMXR.  
break; "3?N*,U_  
} @W|N1,sp  
} 8Qo~zO  
catch(IOException e){e.printStackTrace ();} yF _@^V  
catch(Exception e){e.printStackTrace ();} m|CB')  
u2FD@Xq?  
<=yqV]JR  
Utility.log(nFileLength); &az :YTq  
t_+Xt$Q7C  
='\Di '*  
return nFileLength; +L]$M)*0&  
} TV['"'D&i  
i3SrsVSG  
{9,!XiF.:  
//保存下载信息(文件指针位置) )-u0n] ,  
private void write_nPos() `\pv^#5HV9  
{ 9>OPaL n  
try{ W ZAkp|R  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 'g@Yra&09  
output.writeInt(nStartPos.length); @[=K`n:n_  
for(int i=0;i<nStartPos.length;i++) (b*PDhl`+  
{ ,$,c<M  
// output.writeLong(nPos); KJs/4oR;  
output.writeLong(fileSplitterFetch.nStartPos); q!OB?03n  
output.writeLong(fileSplitterFetch.nEndPos); 1Z$` }a  
} K<g<xW*X  
output.close(); Ofm?`SE*|  
} IQm[ ,Fh  
catch(IOException e){e.printStackTrace ();} >QcIrq%=  
catch(Exception e){e.printStackTrace ();} Vzmw%f)_+  
} 7<Yf  
L3@upb  
%77X/%.Y  
//读取保存的下载信息(文件指针位置) $*k9e^{S  
private void read_nPos() I\8F.J1_  
{ Jfe<$-$$7  
try{ Ed>Dhy6\r  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O'i!}$=g  
int nCount = input.readInt(); -,Oq=w*EV  
nStartPos = new long[nCount]; U?[_ d  
nEndPos = new long[nCount]; p_g#iH!*  
for(int i=0;i<nStartPos.length;i++) 7C::%OF~7  
{ G%q^8#  
nStartPos = input.readLong(); BPwn!ii|  
nEndPos = input.readLong(); w Jr5[p*M  
} N}/|B}  
input.close(); #J): N  
} +%'!+r l  
catch(IOException e){e.printStackTrace ();} en?J#fz  
catch(Exception e){e.printStackTrace ();} 6 o!*bWh  
} '  ~F  
q\r@x-&g+  
qx;8Hq(E[  
private void processErrorCode(int nErrorCode) |u@/,x/t  
{ zQ=c6xvm8  
System.err.println("Error Code : " + nErrorCode); gd,3}@@SH  
} T!F0_<  
5dNM:1VoE  
d8p<f+  
//停止文件下载 M#CYDEB  
public void siteStop() c2o.H!>  
{ -yJ%G1R  
bStop = true; %p(!7FDE2n  
for(int i=0;i<nStartPos.length;i++) ~M !9E])  
fileSplitterFetch.splitterStop(); Y;uQq-CP  
N6%wHNYZ  
^F?}MY>  
} .m^L,;+2  
} e%wzcn  
//负责部分文件的抓取 {pR4+g  
**FileSplitterFetch.java ~ 7^#.  
*/ xaw)iC[gI{  
package NetFox; |Vj@;+/j  
EG&97l b  
)/{zTg8$?/  
import java.io.*; =U- w!uW  
import java.net.*; R?E< }\!  
Xk]:]pl4W  
/]@1IC{Lk  
public class FileSplitterFetch extends Thread { a:V2(nY  
2Vwv#NAV k  
1!P\x=Nn_  
String sURL; //File URL IBn+4 2V  
long nStartPos; //File Snippet Start Position Hdxon@,+cd  
long nEndPos; //File Snippet End Position jY|fP!?[  
int nThreadID; //Thread's ID m5'nqy F  
boolean bDownOver = false; //Downing is over .I#ss66h  
boolean bStop = false; //Stop identical {Y7dE?!`7  
FileAccessI fileAccessI = null; //File Access interface ,jc')#]9B  
- fx?@  
&&s3>D^Ta  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException f$|AU- |<  
{ Ix59(g  
this.sURL = sURL; Gtm|aR{OS  
this.nStartPos = nStart; %={[e`,  
this.nEndPos = nEnd; {n'+P3\T:  
nThreadID = id; .gP}/dj  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;+3XDz v  
} 7+2DsZ^6MW  
KM:k<pvi  
8TH fFL  
public void run() XN Gw@$  
{ Q?xCb  
while(nStartPos < nEndPos && !bStop) q,% lG$0v  
{ g-8D1.U  
$uj3W<iw3E  
>&Ios<67g  
try{ OC5\3H  
URL url = new URL(sURL); nb|KIW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,CED%  
httpConnection.setRequestProperty("User-Agent","NetFox"); p2I9t|  
String sProperty = "bytes="+nStartPos+"-"; l RM7s(^l  
httpConnection.setRequestProperty("RANGE",sProperty); tM DJ,rT  
Utility.log(sProperty); 6!T9VL\=H  
/YrBnccqD  
q?0&&"T}  
InputStream input = httpConnection.getInputStream(); =&,<Co1hF  
//logResponseHead(httpConnection); +aoenUm5  
eR|u']Em>T  
$O[$<D%H  
byte[] b = new byte[1024]; AQU^7O  
int nRead; bZ-_Q  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) gCjW !t  
{ L}hc|(:  
nStartPos += fileAccessI.write(b,0,nRead); Gzw9E.Hk  
//if(nThreadID == 1) ^/M-*U8ab  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l+XTn;cS  
} sogdM{tz\  
6cVJu%<V  
jV 98 2Y  
Utility.log("Thread " + nThreadID + " is over!"); [~Vj(H=KwI  
bDownOver = true; $Le|4Hj  
//nPos = fileAccessI.write (b,0,nRead); J-U5_>S  
} (ptk!u6  
catch(Exception e){e.printStackTrace ();}  &peUC n  
} w'Vm'zo  
} .EB'n{zxd  
IZSJ+KO  
<nk7vo?Ks  
//打印回应的头信息 e anR$I;Yj  
public void logResponseHead(HttpURLConnection con) <_>xkQbn2  
{ <_ruVy0]  
for(int i=1;;i++) {^*K@c  
{ j0uu* )Rk  
String header=con.getHeaderFieldKey(i); u5O`|I@R  
if(header!=null) < .knM  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); AV]7l}-  
Utility.log(header+" : "+con.getHeaderField(header)); ; nc3O{rU  
else nAT,y9&  
break; `P *wz<  
} N/x]-$fl  
} Em]2K:  
ANuO(^  
76eF6N+%}t  
public void splitterStop() `3?5Z/,y  
{ ,k |QuOrCh  
bStop = true; VXP@)\!  
} r>_40+|&  
m'PU0x  
T8W;Lb9hQ  
} E]c0+rh~  
pZ)N,O3  
FByA4VxB  
/*  \<u  
**FileAccess.java +cwuj  
*//文件访问(定位,写) 8Xx4W^*_  
package NetFox; 5MHc gzyp  
import java.io.*; #D ]P3  
:>K8oE  
S.R|Bwj}(Y  
public class FileAccessI implements Serializable{ }'WEqNuE  
9,cMb)=0  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 n%K^G4k^  
RandomAccessFile oSavedFile; rGm xK|R  
long nPos; rr^?9M*{V  
dGG8k&  
bZlKy`Z  
public FileAccessI() throws IOException K:q|M?_  
{ MRN=-|fV^  
this("",0); :-tMH02c  
} +[2ep"5H  
3,^.  
HB*H%>L{"B  
public FileAccessI(String sName,long nPos) throws IOException t_kRYdW9  
{ Y+nk:9  
oSavedFile = new RandomAccessFile(sName,"rw"); ' '<3;  
this.nPos = nPos; jT*?Z:U  
oSavedFile.seek(nPos); 7-VP)|L#G  
} *X\J[$!  
0q o]nw  
3W3)%[ 5  
public synchronized int write(byte[] b,int nStart,int nLen) f-`C1|\w  
{ ] XjL""EbC  
int n = -1; +lw8YH  
try{ 2?nEHIUT  
oSavedFile.write(b,nStart,nLen); cnz+%Y N  
n = nLen; '1"vwXJ"  
} v(P5)R,  
catch(IOException e) g+]o=@  
{ z#*> u  
e.printStackTrace (); Oh5aJ)"D  
} #c$z&J7e  
y`\rb<AZ*t  
gTb%c84  
return n; .~,=?aq^  
} -T2w?|  
5pH6]$  
u$<>8aMei  
} ZVz`g]  
Eg(.L,dj  
6PT"9vR`)  
/* I~Q G  
**SiteInfoBean.java <.=-9O6  
*/   bKt4  
package NetFox; nLY(%):(P  
zALtG<_t  
x7!gmbMfK'  
public class SiteInfoBean { Ejj+%)n.  
QxT\_Nej*n  
oVQbc \P3  
private String sSiteURL; //Site's URL >';UF;\5]Q  
private String sFilePath; //Saved File's Path +1nzyD_E  
private String sFileName; //Saved File's Name r2m&z%N &  
private int nSplitter; //Count of Splited Downloading File a5?Yh<cJ  
PZihC  
]Jo}F@\g  
public SiteInfoBean() -5Oy k,  
{//nSplitter的缺省值为5 $]gflAe2  
//default value of nSplitter is 5 {a0yHy$H  
this("","","",5); Xi0fX$-,  
} sAS[wcOQ  
o>HU4O}  
\V T.bUs  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) hA1p#  
{ L&0aS:  
sSiteURL= sURL; d:{}0hmxI  
sFilePath = sPath; S]Ye`  
sFileName = sName; Z8`Y}#Za[  
this.nSplitter = nSpiltter; uM,R+)3  
-z">ov-)  
V1yP{XT=  
} $|t={s34  
hC?rHw H>  
%Ix2NdC  
public String getSSiteURL() EMzJyGt7  
{ uC%mGZ a  
return sSiteURL; o37D~V;  
} 0 YAH[YF  
dF><XZph  
aKintb}n  
public void setSSiteURL(String value) |nBs(>b  
{ U|Uc|6  
sSiteURL = value; XTRF IY  
}  54#P  
 'Pxq>Os  
CU:HTz=  
public String getSFilePath() \ 027>~u {  
{ JCci*F#r  
return sFilePath; MzH'<`;BP  
} MlR ]+]  
M(vX.kF  
W;?e@}  
public void setSFilePath(String value) OZEbs 7  
{ intl?&wC  
sFilePath = value; xlH3t&i7  
} iK!FVKi}  
VaA.J  
3vdFO: j  
public String getSFileName() 4v` G/w  
{ -$$mrU  
return sFileName; <H$!OPV  
} L tUvFe  
W#2} EX  
"R"{xOQl  
public void setSFileName(String value) @w;$M]o1  
{ )iid9K<HB  
sFileName = value; /D964VR1M\  
} @9~x@[  
[Sj"gLj  
*4%%^*g.I  
public int getNSplitter() A0OA7m:~4  
{ Eihy|p  
return nSplitter; "]|7%]  
} 7A h   
p`EgMzVO,  
xQl}~G]!  
public void setNSplitter(int nCount) &G?"I%Vw  
{ n6G&c4g<"  
nSplitter = nCount; 2@IL  n+#  
} Ze <)B *  
} 8Ltl32JSB[  
Yr>0Qg],  
\01 kK)  
/* &xZSM,  
**Utility.java AD+OQLG]`  
*/ &TL"Hd  
package NetFox; J *38GX+  
;NE4G;px4<  
5A<}*T  
public class Utility { ydA@@C\&  
Uf MQ?(,  
qoZ)"M  
public Utility() ,.h@tN<C  
{ EwmNgmYq  
I9m9`4BK  
}9glr]=  
} jGT|Xo>t  
OMM5ALc(F  
//线程睡眠 5=I"bnIU  
public static void sleep(int nSecond) bZr,jLEf  
{ \hn$-'=4  
try{ ^;F5ymb3U  
Thread.sleep(nSecond); +25=u|#4r  
} e-OKv#]  
catch(Exception e) 1z0|uc  
{ 8I Ip,#%v  
e.printStackTrace (); OCq5}%yU&i  
} Y]5spqG  
} 5W$Jxuyqj  
/Kq'3[d8  
//日志 'Ebjn>"  
public static void log(String sMsg) &=kb>*  
{ }"SqB{5e(  
System.err.println(sMsg); Gs,e8ri!  
} ;)wk ^W  
e ;^}@X  
GgnR*DVP$  
public static void log(int sMsg) C|2|OTtQ  
{ ~mwIr  
System.err.println(sMsg); QPh3(K1w^  
} UvM4-M%2JN  
} \WbQS#Z9  
bwcr/J( Nb  
Fn iht<  
/* AJE$Z0{q  
**TestMethod.java w^("Pg`  
*/ U=7nz|  
package NetFox; J#ClQ%  
qS"#jxc==+  
]T)<@bmL  
public class TestMethod { !dU$1:7  
t%J1(H  
}}ic{931  
public TestMethod() 7!h> < sx  
{ ///xx/weblogic60b2_win.exe IF-y/]  
try{ Jz3,vV fQ:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -(>Ch>O  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ,,+4d :8$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8ICV"8(  
fileFetch.start(); 6GPI gPL,  
} 17,mqXX>  
catch(Exception e){e.printStackTrace ();} +GL$[ 5G  
SWY  
RgL>0s  
} + d3  
pT3icy!A=  
gu%i|-}  
public static void main(String[] args) k3nvML,bv  
{ .Gvk5Wn  
new TestMethod(); , ,ng]&%i  
} eV/oY1B]<  
} Dte5g),R  
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