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http断点续传简单实现(java)

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/* |2?'9<  
**SiteFileFetch.java V `b2TS  
*/ 8}c$XmCM  
package NetFox; ?{\nf7Y  
import java.io.*; ^$%S &W  
import java.net.*; M9Cv wMi  
ZW-yP2  
]=.\-K  
public class SiteFileFetch extends Thread { ?i)f^O  
l,R/Gl  
XxT#X3D/,"  
SiteInfoBean siteInfoBean = null; //文件信息Bean qd9cI&  
long[] nStartPos; //开始位置 vqnw#U4`  
long[] nEndPos; //结束位置 Ipf|")*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !,l9@eJQ  
long nFileLength; //文件长度 m#8m] Y  
boolean bFirst = true; //是否第一次取文件 c|lu&}BS  
boolean bStop = false; //停止标志 ?Y)vGlWDW<  
File tmpFile; //文件下载的临时信息 P7J>+cm  
DataOutputStream output; //输出到文件的输出流 nA?`BOe(  
hhSy0  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) XUM!Qv  
public SiteFileFetch(SiteInfoBean bean) throws IOException VcAue!MN  
{ G %N $C  
siteInfoBean = bean; stG~AC  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 8;z6=.4xtg  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); IYqBQnX}oM  
if(tmpFile.exists ()) @En^wN  
{ g3Ec"_>P  
bFirst = false; Mx6@$tQ%  
read_nPos(); M^MdRu  
} {n(b{ ibl  
else ;6gDV`Twy  
{ j Yx38_5e  
nStartPos = new long[bean.getNSplitter()]; -#0qV:D  
nEndPos = new long[bean.getNSplitter()]; g+DzscIT  
} _6_IP0;  
uG?_< mun  
$u7; TW6QD  
wi hH?~]  
} aY3^C q(r  
1)9sf0LyU  
j;']cWe  
public void run() lwHzj&/ ~  
{ +)kb(  
//获得文件长度 $h^wG)s2P  
//分割文件 _6O\W%it  
//实例FileSplitterFetch bnm P{Ps  
//启动FileSplitterFetch线程 L>MLi3{  
//等待子线程返回 ,RE\$~`w  
try{ yN~dU0.G6!  
if(bFirst)  '/`= R  
{ eKgisY4#  
nFileLength = getFileSize(); y@ ML/9X8q  
if(nFileLength == -1) ykv94i?Q  
{ 2GFLnz  
System.err.println("File Length is not known!"); pM x  
} =2[7 E  
else if(nFileLength == -2) EzDk}uKY0R  
{ r9X?PA0f  
System.err.println("File is not access!"); =2Bg9!zW>  
} JQ}$Aqk  
else >GQEqXs  
{ L~_9_9c  
for(int i=0;i<nStartPos.length;i++) Ks=>K(V6  
{ h lkn%  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); W;_nK4$%'  
} [OHxonU  
for(int i=0;i<nEndPos.length-1;i++) |\QgX%  
{ T~QWRBO  
nEndPos = nStartPos[i+1]; 9!T[Z/}T  
} P6!jRC"52'  
nEndPos[nEndPos.length-1] = nFileLength; X'%E\/~u  
} &L#UGp $,  
} .zS?9MP  
8*8Zc/{  
ki[UV zd  
//启动子线程 Fkvl%n  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; g$HwxA9Gp/  
for(int i=0;i<nStartPos.length;i++) .}'qUPNR  
{ xB_!>SqF1U  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }MRd@ 0-?!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), MHSs!^/g5  
nStartPos,nEndPos,i); tYZ[6 8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }Mo=PWI1?  
fileSplitterFetch.start(); Xg<*@4RD8  
} Se HagKA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :80Z6F.k`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ZaeqOVp/j  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *_R]*o!W'  
nEndPos = " + nFileLength); KiI!frm1  
// fileSplitterFetch[nPos.length-1].start(); O?U'!o=  
)_{dWf1  
ulu9'ch  
//等待子线程结束 /E Bo3`  
//int count = 0; XD|E=s  
//是否结束while循环 x;-. ZVF  
boolean breakWhile = false; C3< m7h  
8i6Ps$T  
v[#9+6P=  
while(!bStop) 9UKp?SIF  
{ hc~s"Atck  
write_nPos(); D!.[q-<  
Utility.sleep(500); ()K " c#  
breakWhile = true; " Om[~-31  
Of{/t1o?  
KC(xb5x Y  
for(int i=0;i<nStartPos.length;i++) Atflf2K  
{  $rz=6h  
if(!fileSplitterFetch.bDownOver) $Z|ffc1  
{ fQ/ 0R  
breakWhile = false; hQ]H /+\  
break; =0^Ruh  
} HFwN  
} BDVHol*g  
if(breakWhile) ]?3un!o3o  
break; zXv3:uRp.  
&C_' p{G  
AFc$%\s4  
//count++; 0TN;86Mo  
//if(count>4) =Vy`J)z9  
// siteStop(); &8%e\W\K:/  
} <,3^|$c%  
%6L^2 X  
b8LoIY*  
System.err.println("文件下载结束!"); @?=|Y  
} 1U^A56CN  
catch(Exception e){e.printStackTrace ();} /rq VB|M  
} S|apw7C  
|~'IM3Jw(Y  
M@4UGM`J  
//获得文件长度 >tO`r.5u9  
public long getFileSize() nA P.^_K  
{ L,mQ   
int nFileLength = -1; PH?#)l D  
try{ `D`sr[3n  
URL url = new URL(siteInfoBean.getSSiteURL()); [[>wB[w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I4i2+ *l}  
httpConnection.setRequestProperty("User-Agent","NetFox"); *g y{]  
j7sKsbb  
0G7K8`a  
int responseCode=httpConnection.getResponseCode(); u}!@ ,/)  
if(responseCode>=400) 'd+N Vj{C  
{ MS0Fl|YA  
processErrorCode(responseCode); dFH$l  
return -2; //-2 represent access is error Fx5d:!]:$?  
} kGdt1N[  
66.5QD0  
JNkwEZhHyg  
String sHeader; vhsk 0$f  
A81ls#is  
U+)xu>I  
for(int i=1;;i++) 3 dht!7/  
{ w"OP8KA:^T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L3 G \  
//Utility.log(in.readLine()); F%i^XA]a*  
sHeader=httpConnection.getHeaderFieldKey(i); |tv"B@`  
if(sHeader!=null) mN!lo;m5  
{ =+-Yxh|*  
if(sHeader.equals("Content-Length")) jeGj<m  
{ 0A,]$Fzt  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); F)s{PCl  
break; w3=%*<  
} dxZu2&gi  
} Ix(?fO#uNF  
else UJfEC0  
break; YqPQ%  
} uq, { tV  
} x~GQV^(l3  
catch(IOException e){e.printStackTrace ();} UB 6mqjPK  
catch(Exception e){e.printStackTrace ();} K'X2dG*  
A5i:x$ww  
P( XaTU&-  
Utility.log(nFileLength); s3]?8hXd  
9G{;?c  
*xON W  
return nFileLength; Pu"R,a  
} K4]g[z  
hoQs @[  
)//I'V  
//保存下载信息(文件指针位置) AC;V m: @{  
private void write_nPos() u0#}9UKQ  
{ VQ0fS!5'  
try{ q EP 4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); hSFn8mpXT  
output.writeInt(nStartPos.length); ax{ ;:fW  
for(int i=0;i<nStartPos.length;i++) _~rI+lA  
{ RRGWC$>?  
// output.writeLong(nPos); ]J:1P`k.  
output.writeLong(fileSplitterFetch.nStartPos); W?eu!wL#p  
output.writeLong(fileSplitterFetch.nEndPos); }~"hC3w  
} x_c7R;C  
output.close(); ZTU&, 1Y;  
} rAs,X  
catch(IOException e){e.printStackTrace ();} 2Fz|fW_  
catch(Exception e){e.printStackTrace ();} VxY+h`4#  
} 7zHh@ B:]  
m;D- u>o  
Wm);C~Le  
//读取保存的下载信息(文件指针位置) $KLD2BAL  
private void read_nPos() mwY IJy[  
{ J?Dq>%+ ^  
try{ txcf=)@>V  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g8w2Vz2/  
int nCount = input.readInt(); )ZBY* lk9  
nStartPos = new long[nCount]; _UT$,0u_i  
nEndPos = new long[nCount]; ^2$ lJ  
for(int i=0;i<nStartPos.length;i++)  qNm$Fx  
{ -jn WZ5.  
nStartPos = input.readLong(); x5QaM.+=J  
nEndPos = input.readLong(); ^S)cjH`P  
} Pt&(npjN,  
input.close(); 'yV?*a  
} b8%C *r7  
catch(IOException e){e.printStackTrace ();} WBNw~|DO]  
catch(Exception e){e.printStackTrace ();} ^-rfvc  
} qwK2WE%T  
\EKU*5\Hp>  
CBDG./  
private void processErrorCode(int nErrorCode) {5d9$v7k4  
{ rQEyD  
System.err.println("Error Code : " + nErrorCode); 5w\fSY  
} 52b*[tZ  
K{ \;2M  
`E!N9qI?t$  
//停止文件下载 <)\y#N  
public void siteStop() 7lS#f1E  
{ p/2jh&  
bStop = true; {@<J_ A  
for(int i=0;i<nStartPos.length;i++) &f7fK|}  
fileSplitterFetch.splitterStop(); V\})3i8  
"dROb}szn  
bu=?N  
} @^;j)%F}  
} N?5x9duK  
//负责部分文件的抓取 w|CZ7|6  
**FileSplitterFetch.java s TOa  
*/ Qb! PRCHQ  
package NetFox; Z0`T\ay  
;L|uIg;.s  
+uBLk0/)>  
import java.io.*; 2_ :n  
import java.net.*;  f>s?4  
r}0\}~'?c  
?H_ LX;r  
public class FileSplitterFetch extends Thread { [! 'op0  
2P]L9'N{Y  
CH fVQ|!\  
String sURL; //File URL :>aQ~1f>]  
long nStartPos; //File Snippet Start Position `xz<>g9e  
long nEndPos; //File Snippet End Position / }Rz=&  
int nThreadID; //Thread's ID }lK3-2Pk  
boolean bDownOver = false; //Downing is over T ]j.=|,d  
boolean bStop = false; //Stop identical Wd0 [%`dq  
FileAccessI fileAccessI = null; //File Access interface Yp0/Ab(v  
4GR!y)  
{8R"O{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ATy*^sc&"  
{ <BSc* 9Q  
this.sURL = sURL; P_c,BlfGMH  
this.nStartPos = nStart; uZZU{U9h  
this.nEndPos = nEnd; 7},)]da>,'  
nThreadID = id; w=|GJ 0  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .TE?KI   
} R/^u/~<  
`+t.!tv!  
U|HB=BP  
public void run()  Y=`  
{ h?-#9<A  
while(nStartPos < nEndPos && !bStop) (;%|-{7e-  
{ GZ{]0$9I'  
,+g&o^T  
bsd99-_(4  
try{ -!0_:m3  
URL url = new URL(sURL); yQ3OL#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &QG6!`fK}3  
httpConnection.setRequestProperty("User-Agent","NetFox"); VdP`a(Yd;  
String sProperty = "bytes="+nStartPos+"-"; {QbvR*gv  
httpConnection.setRequestProperty("RANGE",sProperty); y7S4d~&  
Utility.log(sProperty); /m( =`aRt  
lNv".Y=l  
$7QoMV8V  
InputStream input = httpConnection.getInputStream(); zE)~0v4  
//logResponseHead(httpConnection); Fb/XC:AD  
QI]Ih  
Sa"9^_.2#  
byte[] b = new byte[1024]; Dfd-^N!  
int nRead; SlSM+F  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) EZ.!rh~+  
{ R.LL#u};  
nStartPos += fileAccessI.write(b,0,nRead); m%"uPv\  
//if(nThreadID == 1) pq:7F  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <xJ/y|{  
} #q3l!3\mW  
kz"3ZDR  
Y%|@R3[Nk  
Utility.log("Thread " + nThreadID + " is over!"); eUl/o1~mXa  
bDownOver = true; l{VSb92f  
//nPos = fileAccessI.write (b,0,nRead); |!q$_at  
} @HBEt^!  
catch(Exception e){e.printStackTrace ();} +3i7D  
} 'a^{=+  
} pG^}Xf2a  
>K# ,cxY  
=`Y.=RL+'n  
//打印回应的头信息 Y~)T  
public void logResponseHead(HttpURLConnection con) ^uS/r#l  
{ OG3/-K8R  
for(int i=1;;i++) b dJ+@r  
{ E42eOGp9i  
String header=con.getHeaderFieldKey(i); ]APvp.Tw:  
if(header!=null) dr{y0`CCN  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -[OXSaf6  
Utility.log(header+" : "+con.getHeaderField(header)); Omi^>c4G  
else ?EU\}N J  
break; |wox1Wt|E  
} 8h<ehNX ^I  
} $6F)R|  
xsjO)))f  
pPVRsXy  
public void splitterStop() s cdtWA  
{ 1Uf*^WW4  
bStop = true; +Z!;P Z6  
} =2y8 CgLj  
\n9A^v`F/  
#'OaKt?Z)  
} xt4)Ya  
fag^7rz  
w6 2=06`@  
/* Q,Z*8FH=  
**FileAccess.java `(0LK%w  
*//文件访问(定位,写) bXYA5wG  
package NetFox;  ==/n(LBD  
import java.io.*; $jI>[%  
TP1S[`nR  
,}xbAA#  
public class FileAccessI implements Serializable{ P6Bl *@G  
6zIgQ4Bp24  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *m+5Pr`7  
RandomAccessFile oSavedFile; u)Q;8$`  
long nPos; )a=/8ofe  
^D@b;EyK  
ig0u^BC  
public FileAccessI() throws IOException Q36)7=at  
{ V 'X;jC  
this("",0); :L0/V~D  
} Lc<eRVNd,  
%lr|xX  
'f/Lv@]a  
public FileAccessI(String sName,long nPos) throws IOException +VEU:1Gt  
{ 5 / m$)wE  
oSavedFile = new RandomAccessFile(sName,"rw"); <-UOISyf  
this.nPos = nPos; J NC  
oSavedFile.seek(nPos); n,P5o_^:  
} Swtbl`,  
:9l51oE7  
\g-j9|0  
public synchronized int write(byte[] b,int nStart,int nLen) ,`td@Y  
{ g"Q h]:  
int n = -1; 5;)*T6Y  
try{ %'L;FPxB  
oSavedFile.write(b,nStart,nLen); |!d"*.Q@F  
n = nLen; =A[5= k>  
} tPHS98y  
catch(IOException e) 1'6cGpZY  
{ ZF#Rej?  
e.printStackTrace (); o%M<-l"!/  
} Bk|K%K  
Nq8@Nyp  
W VkR56  
return n; iO!6}yJ*V  
} tUE'K.-  
(L6Cy% KgV  
y[0`hSQ)~  
} j<tq1?? [b  
eukA[nO7G  
!- ~ X?s~L  
/* 3+OsjZ  
**SiteInfoBean.java kpfwqHT  
*/ e[Xq  
package NetFox; m.%`4L^`T  
Aq#/2t  
#y"=Cz=1u7  
public class SiteInfoBean { ,*,sw:=2  
$*~Iu%Az  
g?/XZ5$a5  
private String sSiteURL; //Site's URL US?Rr  
private String sFilePath; //Saved File's Path ~el-*=<m  
private String sFileName; //Saved File's Name _JGs}aQ  
private int nSplitter; //Count of Splited Downloading File j kn^Z":  
~krS#\  
?~ULIO'  
public SiteInfoBean() 9$d.P6|d>  
{//nSplitter的缺省值为5 ~waNPjPRG  
//default value of nSplitter is 5 M<8ML!N0;t  
this("","","",5); )JgC$ <  
} |qjZ38;6  
#I\Y= XCY  
Mpx/S<Z  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |ek ak{js  
{ ?;7b*Z  
sSiteURL= sURL; gb-{2p>}  
sFilePath = sPath; PjqeE,5  
sFileName = sName; @ Gjny BJ  
this.nSplitter = nSpiltter; X, fu!  
A[/I#Im7  
2P~)I)3V  
} A! 6r/   
)3E,D~1e%  
cwtD@KC[B  
public String getSSiteURL() g@nk.aRw  
{ SX+RBVZU  
return sSiteURL; #n})X,ip2  
} 66ohmP@04Z  
^7XAw: ?  
}Zl"9A#K  
public void setSSiteURL(String value) Px4/O~bLk  
{ oNRG25  
sSiteURL = value; NCt~9xS.  
} Up?=m^  
CB}BQd  
sk X]8  
public String getSFilePath() BnEdv8\,&s  
{ rFd@mO  
return sFilePath; x*8O*!ZZ  
} f~\Xg7<  
6M><(1fT  
$-G`&oT  
public void setSFilePath(String value) Lar r}o=  
{ ^Vo"fI`=C  
sFilePath = value; g6' !v  
} W,NL*($^  
E/ O5e(h  
E 5kF^P  
public String getSFileName() PW[6/7  
{ ju{%'D!d9  
return sFileName; X8 qIia  
} T_ ^C#>  
R^{xwI  
cC6z,0`3  
public void setSFileName(String value) }:#dV B+  
{ 0\ f-z6  
sFileName = value; ~iTxv_\=6u  
} 6Y?`=kAp  
 5H.Db  
%x2b0L\g  
public int getNSplitter() )/%S=c  
{ 84`rbL!M  
return nSplitter; xXOw:A'  
} XS/n>C  
V*qY"[   
{8m1dEC^@Q  
public void setNSplitter(int nCount) _Y#Bm/*  
{ {%7<"  
nSplitter = nCount; ~I$}#  
} =R9*;6?N  
} >h7$v~nra  
T&/_e   
nLd~2qBuv  
/* &z ksRX  
**Utility.java 5P\N"Yjx'  
*/ _;G=G5r  
package NetFox; iwo$\  
~07RFR  
NhDA7z`b'J  
public class Utility { 4K,''7N3  
BTs0o&}e  
`vEqj v  
public Utility() b`]M|C [5  
{ 1f;or_f#k?  
UPO^V:.R4  
ysth{[<5F3  
} 5&(3A|P2  
\3j)>u,r  
//线程睡眠 4WG=m}X  
public static void sleep(int nSecond) #Q+R%p  
{ H5p5S\g-)  
try{ \\s?B K  
Thread.sleep(nSecond); =h[yA f  
} @YB85p"]J.  
catch(Exception e) R-C5*$  
{ ,RN|d0dE  
e.printStackTrace (); E0jUewG  
} A^vvST%7  
} u*k*yWdr  
3{q[q#"  
//日志 `oPLl0  
public static void log(String sMsg) aH^{Vv$]M@  
{ [a+4gy  
System.err.println(sMsg); ^Fvr f`A'  
} T^NJ4L4#  
o'^phlX  
Z"N(=B  
public static void log(int sMsg) kxy]vH6m  
{ qOgtGN}k  
System.err.println(sMsg); bQV("~#  
}  2$)mC9  
} < 4$YO-:E  
X#7}c5^Y  
PvuAg(?  
/* D+hB[*7Fs  
**TestMethod.java 19w_tSg  
*/ c.-cpFk^L&  
package NetFox; ;%!tf{Si  
$2is3;h  
wO!% q[  
public class TestMethod { >F|qb*Tm7  
d/4ubf+$k  
Ff&R0v  
public TestMethod() F7V6-V{_  
{ ///xx/weblogic60b2_win.exe 8.-S$^hj~6  
try{ nHVPMi>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); h,.fM}=H  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); OsB?1;:  
SiteFileFetch fileFetch = new SiteFileFetch(bean); soxfk+ 9  
fileFetch.start(); 6~3jn+K$1  
} H.9yT\f.  
catch(Exception e){e.printStackTrace ();} }M?|,N6  
{YBl:rMz  
'DeW<Sa~  
} a>?p.!BM  
LhZZc`|7t  
YPG,9iZ&f  
public static void main(String[] args) <oZ(ng@X  
{ A$N+9n\  
new TestMethod(); oL)lyUVT  
} =kF? _KN  
} lh~<s2[R2  
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