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http断点续传简单实现(java)

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/* ;QPy:x3  
**SiteFileFetch.java vgk9b!Xd  
*/ 8eX8IR!K9  
package NetFox; 05)|"EX)  
import java.io.*; l{EU_|q  
import java.net.*; `p|[rS>  
%cj58zO |y  
1ih*gJPpj  
public class SiteFileFetch extends Thread { R+Lk~X^*l'  
>l2w::l%  
5P\N"Yjx'  
SiteInfoBean siteInfoBean = null; //文件信息Bean _;G=G5r  
long[] nStartPos; //开始位置 tp+=0k2i  
long[] nEndPos; //结束位置 <IH*\q:7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 22vq=RO7Z  
long nFileLength; //文件长度 a|.20w5  
boolean bFirst = true; //是否第一次取文件 [$:@X V(  
boolean bStop = false; //停止标志 Q7k.+2  
File tmpFile; //文件下载的临时信息 QNJ\!+,HV  
DataOutputStream output; //输出到文件的输出流 #JS`e_3Rr  
SsRVd^=;x  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) *<dHqK`?C  
public SiteFileFetch(SiteInfoBean bean) throws IOException u+DX$#-n!]  
{ j |td,82.  
siteInfoBean = bean; 5&(3A|P2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \3j)>u,r  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3U o]> BG  
if(tmpFile.exists ()) jZ#UUnR%  
{ (6-y+ LG  
bFirst = false; 0x#E4v (UA  
read_nPos(); 5mIXyg 0:  
} \\s?B K  
else vzy!3Hiw  
{ @YB85p"]J.  
nStartPos = new long[bean.getNSplitter()]; R-C5*$  
nEndPos = new long[bean.getNSplitter()]; `,m7xJZ?y  
} E0jUewG  
;+9(;  
EE9vk*[@C  
3{q[q#"  
} LaT8l?q q  
v>:=w|.HC  
?%;B`2 nDR  
public void run() L5C2ng>  
{ &CO| Y(+  
//获得文件长度 qZ?{-Vw  
//分割文件 TK %< a/  
//实例FileSplitterFetch %^U"Spv;  
//启动FileSplitterFetch线程 /=ACdJ  
//等待子线程返回 Wxk; g  
try{ *#GDi'0  
if(bFirst) ?&\h;11T  
{ & qL<C  
nFileLength = getFileSize(); #'iPDRYy  
if(nFileLength == -1)  Q>[Ce3  
{ @ AggznA8  
System.err.println("File Length is not known!"); 4L11P  
} '2xcce#  
else if(nFileLength == -2) wzbz }P>  
{ _f66>a<  
System.err.println("File is not access!"); c _p[yS  
} o oDdV >  
else #!1IP~  
{ IadK@?X6j  
for(int i=0;i<nStartPos.length;i++) ;YM]K R;  
{ rFO_fIJno  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1^tSn#j  
} 'tut4SwC  
for(int i=0;i<nEndPos.length-1;i++) :r-.r"[m-  
{ {70 Ou}*  
nEndPos = nStartPos[i+1]; ~K%k 0kT  
} ik1XGFy?  
nEndPos[nEndPos.length-1] = nFileLength; ?4MSgu  
} HoV{Uzm  
} Vp\80D&  
*f?S5 .  
o[n<M> @  
//启动子线程 qr9Imr0w<  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^+URv  
for(int i=0;i<nStartPos.length;i++) b.@H1L  
{ F/xCG nP-  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), u(8~4P0w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), F6DxvyANr  
nStartPos,nEndPos,i); YV4 : 8At1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); MN\i-vAL8  
fileSplitterFetch.start(); PRZ8X{h  
} Dl&PL  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), x g{VP7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); f~U#z7  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", K:uQ#W.&  
nEndPos = " + nFileLength); f%L:<4  
// fileSplitterFetch[nPos.length-1].start(); C)U #T)  
A3<^ U  
Xn PJC'  
//等待子线程结束 e"lD`*U8R  
//int count = 0; yr%yy+(.k  
//是否结束while循环 2c"/QT  
boolean breakWhile = false; A0UV+ -PP  
5d%_Wb'  
8F\~Wz7K  
while(!bStop) m'3OGvd  
{ ZRX^^yN  
write_nPos(); f!mE1,eBEe  
Utility.sleep(500); BB0g}6M  
breakWhile = true; /G{&[X<4U  
\ hrBq^I  
I7A7X*  
for(int i=0;i<nStartPos.length;i++) u/;_?zI  
{ cl@kRX<7'  
if(!fileSplitterFetch.bDownOver) FoQ?U=er  
{ 2.!1kije  
breakWhile = false; F9v)R #u~  
break; ~d&'Lp[3  
} u"*J[M~  
} aD?# ,  
if(breakWhile) ;,mBT[_ZO  
break; %Fs*#S  
K?$ 9N}+  
AL(n *,  
//count++; i[o&z$JO  
//if(count>4) sN"p5p  
// siteStop(); gHp'3SnS  
} >c}:   
q|R+x7x  
 ^8b~ZX  
System.err.println("文件下载结束!"); ! Zno[R  
} 4u@yJ?U  
catch(Exception e){e.printStackTrace ();} (6e!09P&  
} =VCi8jDkP  
/]pX8 d  
Dp%5$wF)8  
//获得文件长度 W]} #\\$z  
public long getFileSize() u):X>??  
{ jG =(w4+  
int nFileLength = -1; A J<iM)l|  
try{ X77A; US  
URL url = new URL(siteInfoBean.getSSiteURL()); @gs26jX~2}  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 37J\i ]  
httpConnection.setRequestProperty("User-Agent","NetFox"); <GSQ2bX[  
ww-XMz h  
|*lH9lWJ  
int responseCode=httpConnection.getResponseCode(); A$%@fO.b  
if(responseCode>=400) Q~x*bMb.  
{ j@%K*Gb`  
processErrorCode(responseCode); >|v=Ba6R0  
return -2; //-2 represent access is error p Z0=  
} t^`<*H  
Z'voCWCd  
5Xp$ yX =  
String sHeader; 8W(<q|t  
w g$D@E7  
ac2}3 $u  
for(int i=1;;i++) N;e;4,_ n  
{ OJnPP>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -OHvK0~  
//Utility.log(in.readLine()); pI'8>_o  
sHeader=httpConnection.getHeaderFieldKey(i); _K 4eD.  
if(sHeader!=null) $ijx#a&O  
{ 8yY"x ['  
if(sHeader.equals("Content-Length")) ; :v]NZtc  
{ Q,[rrG;?@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); oc!biE`u  
break; j4.Qvj >:4  
} L-^# 02  
}  Bq~AU#  
else \W3+VG2cA  
break; N{?Tm`""  
} 43UJ#rF  
} v]LFZI5  
catch(IOException e){e.printStackTrace ();} fs]#/*RR  
catch(Exception e){e.printStackTrace ();} .d<~a1k  
P58\+9d_  
jrDz7AfA  
Utility.log(nFileLength); rU/-Wq`B  
qkIA,Kgy  
v1`bDS?*Q  
return nFileLength; tXssejiE%  
} zv$=*  
$#6 Fnhh}  
/ig^7+#  
//保存下载信息(文件指针位置) @t{{Q1  
private void write_nPos() yVbg,q'?  
{ @ef//G+Z"  
try{ {jj]K.&  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ;`X`c  
output.writeInt(nStartPos.length); Y?"v2~;3  
for(int i=0;i<nStartPos.length;i++) fY| @{]rx  
{ KUl Zk^a  
// output.writeLong(nPos); , V0iMq  
output.writeLong(fileSplitterFetch.nStartPos); $ioaunQKP  
output.writeLong(fileSplitterFetch.nEndPos); TMnT#ypf<5  
} umq$4}T '$  
output.close(); &4ug3  
} !?tu! M<1?  
catch(IOException e){e.printStackTrace ();} }w|=c >'_}  
catch(Exception e){e.printStackTrace ();} AxG?zBTFx  
} Y/?DSo4G  
:epitpJ  
e8WPV  
//读取保存的下载信息(文件指针位置) jgZX ~D  
private void read_nPos() I1eb31<  
{ E 6>1Fm8%V  
try{ g4BwKENM  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); B1 jH.(  
int nCount = input.readInt(); C9"f6>i  
nStartPos = new long[nCount]; UgOGBj,&5W  
nEndPos = new long[nCount]; FvtM~[Q  
for(int i=0;i<nStartPos.length;i++) jk WBw.(  
{ K-g=td/@  
nStartPos = input.readLong(); &;uGIk>s  
nEndPos = input.readLong(); A;/Xt  
} ;iwD/=Y  
input.close(); LN,$P  
} }RC. Q`b  
catch(IOException e){e.printStackTrace ();} m\R@.jkZ  
catch(Exception e){e.printStackTrace ();} (o6A?37i  
} _BeX7  
gn;nS{A  
f"} 0j|Gg  
private void processErrorCode(int nErrorCode) ;I0yQlx|U  
{ @n ~ND).  
System.err.println("Error Code : " + nErrorCode); RN cI]oJ  
} <E(-QJ  
o$qFa9|Ec?  
9I^H)~S  
//停止文件下载 S%a}ip&  
public void siteStop() L@^ !(  
{ ]9~#;M%1  
bStop = true; <+mO$0h"r  
for(int i=0;i<nStartPos.length;i++) gvwCoCbb  
fileSplitterFetch.splitterStop(); 9e :d2  
MO(5-R`  
;1(qGy4  
} |?pYJkrYO  
} <7RkM  
//负责部分文件的抓取 \a~;8):q=i  
**FileSplitterFetch.java XH_qA[=c]  
*/ Cbf,X[u  
package NetFox; +wPvQKVfI  
+@<^i?ale  
SbQ{ >  
import java.io.*; ni02N3R  
import java.net.*; OM.(g%2  
,rvZW}=  
MZhJ,km)  
public class FileSplitterFetch extends Thread { Z)Xq!]~/g  
pqNoL* H  
2-B8>-   
String sURL; //File URL 37<GG)  
long nStartPos; //File Snippet Start Position /fcwz5~  
long nEndPos; //File Snippet End Position E!(`275s  
int nThreadID; //Thread's ID 'KN!m| z  
boolean bDownOver = false; //Downing is over _#\5]D~""  
boolean bStop = false; //Stop identical z;@S_0M,Z  
FileAccessI fileAccessI = null; //File Access interface #f jX|b  
z<C~DH  
!UPAEA  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException aV0;WH_3  
{ v2dSC(hRZ  
this.sURL = sURL; $(<*pU  
this.nStartPos = nStart; -^SD6l$  
this.nEndPos = nEnd; s$=B~l  
nThreadID = id; fjeE.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B+e~k?O]1  
} xX67bswG  
l<+,(E=  
<P Z\qE*+y  
public void run() _|2";.1E  
{ g]hn@{[  
while(nStartPos < nEndPos && !bStop) rO2PbF3  
{ fe]T9EDA  
^dp[ Z,[1z  
jl ?y}  
try{ =K&q;;h  
URL url = new URL(sURL); M. UUA?d<'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); vA $BBXX  
httpConnection.setRequestProperty("User-Agent","NetFox"); D\i8rqU/l  
String sProperty = "bytes="+nStartPos+"-"; s13 d*  
httpConnection.setRequestProperty("RANGE",sProperty); rH9|JEz  
Utility.log(sProperty); ,19"[:WN  
Q!$kUcky9  
q?b)zeJ  
InputStream input = httpConnection.getInputStream(); 39^uLob  
//logResponseHead(httpConnection); ;kcFQed\w  
^gVbVz[17  
Zp P6Q  
byte[] b = new byte[1024]; 9R<J$e  
int nRead; ,HjHt\!~<  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) X wn|.  
{ N6 Cc%,  
nStartPos += fileAccessI.write(b,0,nRead); m]b.P,~v  
//if(nThreadID == 1) +r34\mAO  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); i_Q4bhVj  
} Z_TbM^N  
@eD2<e  
W71#NjM2Z  
Utility.log("Thread " + nThreadID + " is over!"); EC&19  
bDownOver = true; 8CHf.SXh  
//nPos = fileAccessI.write (b,0,nRead); 'J<zVD}0  
} "\P~Re"EH  
catch(Exception e){e.printStackTrace ();} Hwi7oXP  
} :Y&W)V-  
} ?F:C!_  
6(Rq R  
)}Mt'd  
//打印回应的头信息 gj(l&F *@  
public void logResponseHead(HttpURLConnection con) 8*X L19N  
{ d(cYtM,P  
for(int i=1;;i++) 2LK*Cv[  
{ jZgnt{  
String header=con.getHeaderFieldKey(i); `[R:L.H1  
if(header!=null) pl? J<48  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); SF}L3/C&h  
Utility.log(header+" : "+con.getHeaderField(header)); kA$;vbm  
else '[M2Q"X  
break; gbi~!S-  
} w[7HY@[  
} X([n>w  
a}8>(jtSt  
n@8{FoF  
public void splitterStop() qv >(  
{ XT;IEZQZ  
bStop = true; 7UnO/K7oB.  
} v?iH}7zb%Q  
CX(yrP6;  
`E%d$  
} 2tTV5,(1  
yvnrZ&x :  
Ib<+m%Ac  
/* <UHf7:0V  
**FileAccess.java kT3;%D^  
*//文件访问(定位,写) uTF EI.N  
package NetFox; vVRCM  
import java.io.*; K>E!W!-PJ  
%.  }  
%1l80Z  
public class FileAccessI implements Serializable{ st^N QL  
UVi/Be#|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9(\N+  
RandomAccessFile oSavedFile; I;PO$T  
long nPos; <. ]&FPJ  
GoGgw]h>x  
N1zrfn-VU  
public FileAccessI() throws IOException LWR &(p.%  
{ -|UX}t*  
this("",0); $zH 0$aOx  
} 2G*#Czr"  
F973U  
G@6,O-Sj  
public FileAccessI(String sName,long nPos) throws IOException Wam?(!{mOf  
{ C)dYAq3,8  
oSavedFile = new RandomAccessFile(sName,"rw"); WUQh[A41  
this.nPos = nPos; Fd=`9N9  
oSavedFile.seek(nPos); @g` ,'r  
} JaN_[ou  
`'t;BXedz/  
I ywx1ac  
public synchronized int write(byte[] b,int nStart,int nLen) 23?0'AU  
{  PW\FcT  
int n = -1; V)?g4M3}  
try{ i(#c Yb  
oSavedFile.write(b,nStart,nLen); rm;"98~zJ?  
n = nLen; , X+(wp  
} 4E94W,1%,Y  
catch(IOException e) LPgI"6cP  
{ .EELR]`y7I  
e.printStackTrace (); M/I d\~  
} X64I~*  
Rs`Y'_B  
[~0q )  
return n; uw&,pq  
} #GJh:#tt^  
ooxzM `  
_^A NJ7  
} _Pm}]Y:_  
F#R\Ot,hv  
 K8we*  
/* soCHwiE  
**SiteInfoBean.java _ o3}Ly}  
*/ c.> (/  
package NetFox; fXQRsL8 ]  
"C|l3X'  
CzbNG^+  
public class SiteInfoBean { +u)$o  
PA[Rhoit,  
s&hP^tKT  
private String sSiteURL; //Site's URL `h]f(  
private String sFilePath; //Saved File's Path JQ4>S<ttJ  
private String sFileName; //Saved File's Name F'Vl\qPt  
private int nSplitter; //Count of Splited Downloading File sM_e_e  
oVgNG!/c0  
}# ^Pb M  
public SiteInfoBean() y=`(`|YW}`  
{//nSplitter的缺省值为5 2C&%UZim;P  
//default value of nSplitter is 5 a VMFjkW  
this("","","",5); \5_^P{p7<  
} (LPc\\Vv  
4(gf!U  
p-Btbhv  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) K Hc+  
{ e4LNnJU\|  
sSiteURL= sURL; t fQq3#  
sFilePath = sPath; (HxF\#r?  
sFileName = sName; ^%^0x'"  
this.nSplitter = nSpiltter; 9jO+ew  
N$b;8F  
I'YotV7  
} (`xnA~BN  
dkC/ ?R  
B\yq% m  
public String getSSiteURL() pP& M]'  
{ ^a5>`W  
return sSiteURL; a"4 6_>  
} {P+[C O  
c^k. <EA  
-qF|Y f  
public void setSSiteURL(String value) rpWy 6oD  
{ #+\G- =-  
sSiteURL = value; 9mm(?O~'p  
} /ep~/#Ia  
?8/h3xV;  
_\[G7  
public String getSFilePath() ,oil}N(  
{ 1>{(dd?L  
return sFilePath; 2N]s}/l  
} 8m0sEV>  
>S]')O$c  
V|`|CVFo]  
public void setSFilePath(String value) Zv93cv  
{ VV0$L=mo  
sFilePath = value; :Yqa[._AF  
} m ws.)  
@xE Q<g  
`Mg "!n`  
public String getSFileName() z(qz(`eGC&  
{ e+TNG &_  
return sFileName; IF1}}[Ht  
} f6)H!SI  
cO9Aw!  
yW 3h_08  
public void setSFileName(String value) `314.a6S  
{ <Vb{QOgc;  
sFileName = value; J;dFmZOk  
} *Q?HaG|S  
yM@cml6Ox  
rv:O|wZ  
public int getNSplitter() $)!Z"2T  
{ r^)<Jy0|r  
return nSplitter; =B1!em|  
} ;Lu|fQ#u*  
\BW(c)Q  
QR4o j  
public void setNSplitter(int nCount) /_\4( vvf  
{ /Y:Zqk3  
nSplitter = nCount; HFOp4  
} ^Tx1y[hw$  
} ;f Gi5=-  
4tjRju?  
Hw? J1#1IE  
/* >B0S5:S$W  
**Utility.java ??PpHB J')  
*/ ,U}8(D~:  
package NetFox; Qs a2iw{  
cf9y0  
4.TG&IQ nN  
public class Utility { U' Cp3>  
DNPK1e3a{  
<3KrhhH  
public Utility() ;<\*(rUe  
{ v]v f(]""  
tr Ls4o,  
N<x5:f#+  
} dq2v[? *R  
c1[;a>  
//线程睡眠 novZ<?7 5;  
public static void sleep(int nSecond) 6c:$[owC  
{ X9R-GT  
try{ W2RS G~|  
Thread.sleep(nSecond); |d K-r  
} H UjmJu6f{  
catch(Exception e) "<n{/x(  
{ tyh%s"  
e.printStackTrace (); B}W^s;h  
} _~!,x.Dbp  
} i!NGX  
4J  s>yP  
//日志 JsV#:  
public static void log(String sMsg) #!2gxm;g  
{ $a G'.0HW  
System.err.println(sMsg); !E%!,  
} Xp' KQ1w)  
a <3oyY'  
^P[*yf  
public static void log(int sMsg) UxW~yk  
{ bWqGy pq4  
System.err.println(sMsg); QO8/?^d  
}  [7bY(  
} W6pS.}  
jV(IS D  
\vI_%su1N  
/* |l9AgwDg  
**TestMethod.java %UmE=V  
*/ bnlL-]]9z  
package NetFox; R~`Y6>o~9:  
(/%}a`2#o  
<^=k~7m  
public class TestMethod { ZrTq)BZ  
_Qv4;a  
)YZ41K5N  
public TestMethod() _u>+H#  
{ ///xx/weblogic60b2_win.exe Z1Ms ~tch  
try{ :!%oQQO  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); X **w RF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _?{2{^v  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 6c2fqAF>i  
fileFetch.start(); q+K`+& @\  
} nP}/#Wy  
catch(Exception e){e.printStackTrace ();} RKe19l_V  
zmdOL9"a  
,yB-jk?  
} +/ #J]v-  
cJt#8P  
rTi.k  
public static void main(String[] args) ^#G>P0mG%  
{  (vY10W{  
new TestMethod(); L9x,G!  
} F*a+&% Q  
} t<e?f{Q5  
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