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http断点续传简单实现(java)

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/* t p3 !6I6  
**SiteFileFetch.java bc*CP0t|  
*/ "P8cgj C  
package NetFox; G297)MFF  
import java.io.*; -jL10~/  
import java.net.*; PRyzUG&  
xSZ+6R|  
?H(']3X5@  
public class SiteFileFetch extends Thread { eih~ SBSH  
d<afO?"  
ynG@/S6)K  
SiteInfoBean siteInfoBean = null; //文件信息Bean Mp`i@pm+  
long[] nStartPos; //开始位置 j<_)Y(x>  
long[] nEndPos; //结束位置 ?wbf)fbq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 pwr]lV$w  
long nFileLength; //文件长度 WxF0LhM  
boolean bFirst = true; //是否第一次取文件 bWfT-Jewh  
boolean bStop = false; //停止标志 35fsr=  
File tmpFile; //文件下载的临时信息 9i/VvW  
DataOutputStream output; //输出到文件的输出流 _J33u3v  
[5s4Jp$+  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) @N+6qO}  
public SiteFileFetch(SiteInfoBean bean) throws IOException XiN@$  
{ _6{XqvWqb  
siteInfoBean = bean; x_BnWFP  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); J+0T8 ?A  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $ 2PpG|q  
if(tmpFile.exists ()) ? EXYLG  
{ fs%l j_t  
bFirst = false; )w&k&TY4H  
read_nPos(); jij-pDQnv  
} C(lGW,!  
else XXZ<r  
{ z Feo8S  
nStartPos = new long[bean.getNSplitter()]; '7/c7m/$X<  
nEndPos = new long[bean.getNSplitter()]; W)m\q}]FYz  
} Y8%*S%yO  
vHxLn/  
m<| *  
y?yWM8  
} @DA.$zn&  
KPMId`kf  
cuo'V*nWQ  
public void run() ":,J<|Oy  
{ Y SD|#0  
//获得文件长度 4WZ"8  
//分割文件 O2C&XeB:4  
//实例FileSplitterFetch /yO|Q{C}M8  
//启动FileSplitterFetch线程 \N"=qw^ t  
//等待子线程返回 w2e 9Ue~WH  
try{ +'QE-#%{=  
if(bFirst) ^%~ux0%^T  
{ ZT%Q:]B+  
nFileLength = getFileSize(); f%5 s8)  
if(nFileLength == -1) ? _Y2'O  
{ Z^SF $+UN  
System.err.println("File Length is not known!"); !_#2$J*s^D  
} ;$$.L bb8  
else if(nFileLength == -2) 9a lMC  
{ ;ZowC#j  
System.err.println("File is not access!"); &WAJ;7f  
} %P tdFz$  
else ]9/{  
{ 15tT%TC  
for(int i=0;i<nStartPos.length;i++) $g+q;Y~i0  
{ 5>*~1}0T  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |}^ BF%8V:  
} e:kd0)9  
for(int i=0;i<nEndPos.length-1;i++) OXCf  
{ _vgFcE~E@  
nEndPos = nStartPos[i+1]; %q)*8  
} g6 Nw].{  
nEndPos[nEndPos.length-1] = nFileLength; .cA'6J"Bm\  
} :bV1M5  
} DQRr(r~2Kj  
>xJh!w<pB  
w,v~  
//启动子线程 etkKVr;Kv  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +1Ua`3dWN_  
for(int i=0;i<nStartPos.length;i++) pXv@ QD#!  
{ t (>}  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 'k(aZ"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), XDcA&cM}p  
nStartPos,nEndPos,i); EAi!"NJ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tWN hFQ'  
fileSplitterFetch.start(); Eggdj+  
} wEJ) h1=)^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s`Z'5J;S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8O0E;6b  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", A,'JmF$d  
nEndPos = " + nFileLength); B>"O~ gZ{#  
// fileSplitterFetch[nPos.length-1].start(); 1hnw+T<<W  
xU_Dg56z'&  
3iC$ "9!p  
//等待子线程结束 I? o)X!  
//int count = 0; (#`1[n+b`x  
//是否结束while循环 v?en-,{A  
boolean breakWhile = false; #\X="' /  
Yl!~w:O!o  
+ IpC  
while(!bStop) xesZ 7{ o  
{ G(6MLh1  
write_nPos(); )r^)e 4UI  
Utility.sleep(500); 3 2MdDa  
breakWhile = true; Fv(1A_~IS  
vq&u19iP  
rp^G k  
for(int i=0;i<nStartPos.length;i++) <>tQa5;  
{ \uT y\KA  
if(!fileSplitterFetch.bDownOver) !?u{2 D  
{ ~gA p`Q  
breakWhile = false; ;mw$(ZKa#  
break; _K5R?"H0  
} <5wk~|@t  
} <B %s9Zy  
if(breakWhile) V<%eWT)x7C  
break; 9;*-y$@  
&>]c"?C*  
V`/D!8>  
//count++; FhkS"y  
//if(count>4) eVy>  
// siteStop(); $x'p+&n\  
} +>uiI4g  
-lNq.pp3-$  
6bXR?0$*M.  
System.err.println("文件下载结束!"); WzwH;!  
} [~[)C]-=  
catch(Exception e){e.printStackTrace ();} RZg8y+jM  
} 5!pof\/a  
$V0G[!4  
Bl"BmUn  
//获得文件长度 =K ctAR;  
public long getFileSize() ra4$/@3n  
{ 7\?0d!  
int nFileLength = -1; iE;D_m.>`O  
try{ !8 V  
URL url = new URL(siteInfoBean.getSSiteURL()); yK3b^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -~'{WSJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); ZgP~VB0)$  
1'G&PX   
n8dJ6"L<"  
int responseCode=httpConnection.getResponseCode(); qij<XNZU"&  
if(responseCode>=400) I \DH  
{ XFiP8aX<  
processErrorCode(responseCode); &=-ZNWNo  
return -2; //-2 represent access is error ev}ugRxt|k  
} &eqeQD6  
*49lM;  
vTdJe  
String sHeader; hN3*]s;/6z  
6(5YvT  
knsTy0]  
for(int i=1;;i++) c :{#H9  
{ 4N- T=Ig  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =>kE`"{!  
//Utility.log(in.readLine()); V4.&"0\n#  
sHeader=httpConnection.getHeaderFieldKey(i); G'M;]R9EP  
if(sHeader!=null) K#e&yY  
{ k+D"LA%J  
if(sHeader.equals("Content-Length")) _,?<r&>v6  
{ KT>eE  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); oN\IQ7oI  
break; +[R,wsG  
} ,@#))2<RK  
} DNGXp5I  
else +p Y*BP+~i  
break; |*T3TsP u  
} ~g|Z6-?4Jj  
} R iPxz=kr  
catch(IOException e){e.printStackTrace ();} !)1gGXRY  
catch(Exception e){e.printStackTrace ();} /YLHg5n8+  
R|&Rq(ow"  
Sz_{#-  
Utility.log(nFileLength); Z?);^m|T  
QQPT=_P]  
Mkj`  
return nFileLength; 9[5qN!P;y  
} jgW-&nK!  
iaAj|:  
IOjp'6Yr  
//保存下载信息(文件指针位置) iiw\  
private void write_nPos() y$Rr,]L  
{ VPh0{(O^=  
try{ /~O>He  
output = new DataOutputStream(new FileOutputStream(tmpFile)); j^V r!y  
output.writeInt(nStartPos.length); 6VsgZ"Il  
for(int i=0;i<nStartPos.length;i++) x/B1\U I  
{ UK7pQt}9  
// output.writeLong(nPos); :"~SKJm  
output.writeLong(fileSplitterFetch.nStartPos); S /kM#  
output.writeLong(fileSplitterFetch.nEndPos); 4*D'zJsJ  
} $\w<.)"#  
output.close(); <Pm!#)-g9  
} b:M1P&R  
catch(IOException e){e.printStackTrace ();} /Z?$!u4I  
catch(Exception e){e.printStackTrace ();} Bo#,)%80  
} &qjc+-r{l  
1z6$>{FUR  
wOLDHg_  
//读取保存的下载信息(文件指针位置) jGSY$nt9  
private void read_nPos() ieL7jN,'m  
{ !<8-juY  
try{ T@4R|P&{)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?^Q8#Y^M  
int nCount = input.readInt(); 2d#3LnO  
nStartPos = new long[nCount]; Q:5^K  
nEndPos = new long[nCount]; 4!</JZX~$  
for(int i=0;i<nStartPos.length;i++) bih%hqny  
{ +QZ}c@'r  
nStartPos = input.readLong(); N*w6D:  
nEndPos = input.readLong(); nr{#Krkb  
} @CTSvTt$  
input.close(); u{'|/g&  
} ].Sz2vI  
catch(IOException e){e.printStackTrace ();} Z0'&@P$  
catch(Exception e){e.printStackTrace ();} 44x+2@&1  
} =.48^$LWx  
\x7^ly$_  
h]>QGX[kC  
private void processErrorCode(int nErrorCode) CQANex4&\  
{ $SOFq+-T  
System.err.println("Error Code : " + nErrorCode); L7`=ec<  
} =] +owl2  
m}$7d5  
E^`-:L(_  
//停止文件下载 w!eY)p<  
public void siteStop() {M^BY,%*  
{ [KMNMg  
bStop = true; */6lyODf  
for(int i=0;i<nStartPos.length;i++) TFAd  
fileSplitterFetch.splitterStop(); +e87/\5  
4aGVIQ  
$VxKv7:  
} nf0]<x2  
} \V_ Tc`  
//负责部分文件的抓取 VrIR!9%:  
**FileSplitterFetch.java r6Qsh CA"  
*/ Ht"?ajW{  
package NetFox; B{lj.S` mB  
Bc*FH>E  
&|K9qa~)Y  
import java.io.*; *yZ `aKfH  
import java.net.*; {zTnE?(o`  
YZ k.{#^c  
XkhGU?={  
public class FileSplitterFetch extends Thread { 67g"8R#.V  
FX1H2N(  
EvKzpxCh  
String sURL; //File URL X=KC +1e  
long nStartPos; //File Snippet Start Position W8_$]}G8E  
long nEndPos; //File Snippet End Position idNra#  
int nThreadID; //Thread's ID Rz#q68  
boolean bDownOver = false; //Downing is over ^?8/9 o  
boolean bStop = false; //Stop identical ;EB^1*A Ew  
FileAccessI fileAccessI = null; //File Access interface `oU|U!|  
/&  W&  
0NF=7 j  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ZYS]Et[Q  
{ |JLXgwML  
this.sURL = sURL; oMNSQMlI  
this.nStartPos = nStart; N XCvS0/h  
this.nEndPos = nEnd; ='t}d>l  
nThreadID = id; {[)n<.n[g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 vB%os Qm  
} gkmV; 0  
1N}vz(0"  
)`BKEa f  
public void run() p/U{*i ]t  
{ 4:9N]1JCb  
while(nStartPos < nEndPos && !bStop) mIZ6[ ?  
{ :2.<JUDM  
jx{wOb~oO)  
z*UgRLKZD  
try{ Y:R*AOx  
URL url = new URL(sURL); ni85Ne$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); =<%[P9y  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4nrn Npf`b  
String sProperty = "bytes="+nStartPos+"-"; EO`eg]  
httpConnection.setRequestProperty("RANGE",sProperty); ?2%;VKN4  
Utility.log(sProperty); aD+4uGN  
wJZuJ(  
q5G`q&O5  
InputStream input = httpConnection.getInputStream(); {e5DQ21.  
//logResponseHead(httpConnection); v`@NwH<r  
/Nkxb&  
*M ^ <oG  
byte[] b = new byte[1024]; 5P{[8PZxbV  
int nRead; cLf<YF  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,M9e *  
{ bq2f?uD-}  
nStartPos += fileAccessI.write(b,0,nRead); v5F+@ug  
//if(nThreadID == 1) :8`~dj.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3rY\y+m  
} y_' 6bpb  
U=WS]  
x5|^p=  
Utility.log("Thread " + nThreadID + " is over!"); 3 "iBcsLn  
bDownOver = true; "AP$)xM-:  
//nPos = fileAccessI.write (b,0,nRead); )Dp0swJ  
} CTS1."kx1  
catch(Exception e){e.printStackTrace ();} q B IekQT  
} \n`/?\r.z  
} PthgxB^  
4.p:$/GTS  
+e, c'.  
//打印回应的头信息 \zc R7 5  
public void logResponseHead(HttpURLConnection con) UM/!dt}DnF  
{ 6e8 gFQ"w2  
for(int i=1;;i++) .DI?-=p|_#  
{ osl\j]U8  
String header=con.getHeaderFieldKey(i); 2qot(Zs1i  
if(header!=null) K3Bw3j 9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d'"|Qg_'  
Utility.log(header+" : "+con.getHeaderField(header));  wX5q=I  
else d N$,AOT  
break; !S%0#d2  
} 1F_$[iIX]  
} ('{aOiSH  
_, E/HAX  
Cs(sar:7  
public void splitterStop() >(-A"jf  
{ *4e?y  
bStop = true; \1SC:gN*#  
} ]}kw'&  
ap8q`a{j^  
4l7 Ny\J  
} zn>+ \  
d@p#{ -  
ZS%W/.?  
/* ;{aGEOP'U  
**FileAccess.java :}yT?LIyP  
*//文件访问(定位,写) Af\  
package NetFox; Vm[F~2+HX  
import java.io.*; 1Au+X3   
Xo:Mar  
hbg$u$1`,  
public class FileAccessI implements Serializable{ /wax5FS'I,  
KZTLIZxI-  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 OLqV#i[K#9  
RandomAccessFile oSavedFile; u>]3?ty`  
long nPos; jo^c>ur  
n\M8>9c  
Y!8FW|  
public FileAccessI() throws IOException ="5D}%  
{ c6lCF &  
this("",0); [_nOo`  
} @TQ/Z$y  
F}7sb#G  
@gfW*PNjlP  
public FileAccessI(String sName,long nPos) throws IOException lKB9n}P  
{ l^d'8n  
oSavedFile = new RandomAccessFile(sName,"rw"); >[Wjzg  
this.nPos = nPos; 0k{\W  
oSavedFile.seek(nPos); b"Q8[k |d  
} YVwpqOE.=  
Xl<iR]lda  
 |iI dm  
public synchronized int write(byte[] b,int nStart,int nLen) 3C<G8*4);/  
{ BM/o7%]n  
int n = -1; l=b!O  
try{ K"x_=^,Yu*  
oSavedFile.write(b,nStart,nLen); [@ev%x,  
n = nLen; 8>t,n,k  
} ,0a_ou"P=_  
catch(IOException e) swxX3GR  
{ 2QRO$NieV  
e.printStackTrace (); 8}m J )9<7  
} p<{P#?4 g  
tsJR:~  
M2-`p  
return n; SAdE9L =d  
} ^?Mp(o  
@lF?+/=$  
t^KQ*8clG  
} Ku%tM7ad  
Ny^f'tsA  
}%8ZN :  
/* FGx)?  
**SiteInfoBean.java p<=Lh47 =  
*/ mf3,V|>[\  
package NetFox; &hO-6(^I  
BLy V~   
ewU*5|*[  
public class SiteInfoBean { 6{buel(|e  
?UAuUFueA  
fwv^dEe  
private String sSiteURL; //Site's URL $j.;$~F  
private String sFilePath; //Saved File's Path 88~Nrl=co  
private String sFileName; //Saved File's Name -n&&d8G^s  
private int nSplitter; //Count of Splited Downloading File $C;i}q#  
-0d9,,c  
*,4rYb7I w  
public SiteInfoBean() 7h}gIm7e"  
{//nSplitter的缺省值为5 q* p  
//default value of nSplitter is 5 (|K+1R  
this("","","",5); "-$}GUK?Z  
} Jg;[k  
1~c\J0h)d  
P|<V0 Vs.  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ~^1y(-cw  
{ 0[l}@K?  
sSiteURL= sURL; 'z;(Y*jb  
sFilePath = sPath; =G:Krc8w@  
sFileName = sName; lH4Nbluc^  
this.nSplitter = nSpiltter; EwzR4,r\M  
R^.PKT2E  
BA c+T  
} TRGpE9i  
k sv]  
S&` 6pN  
public String getSSiteURL() |reA`&<q  
{ ^YLC{V  
return sSiteURL; u2oS Ci  
} [f_^B U&  
<a"(B*bBd  
$pES>>P  
public void setSSiteURL(String value) _ p\L,No  
{ Wk0E7Pr  
sSiteURL = value; ']1n?K=A  
} mH$tG $  
['IH*gi  
KV_/fa~Ry  
public String getSFilePath() ^aSb~lce  
{ irAXXg  
return sFilePath; cW:y^(Xii  
} =\O#F88ui  
% "(&a'B  
Me .I>7c  
public void setSFilePath(String value) lcdhOjz!N  
{ ^O_Z5NbC3  
sFilePath = value; M@cFcykK  
} Te-p0x?G.  
[7vV#s3kJ  
G,)zn9X  
public String getSFileName() RsZj  
{ cqG6di7#  
return sFileName; EV?}oh"x  
} H>C bMz1u  
O-(V`BZe  
7_I83$p'  
public void setSFileName(String value) l8oaDL\f  
{ [Z$H <m{c-  
sFileName = value; B7 s{yb  
} WQ9e~D"  
fQfn7FaW_\  
VE+H! ob A  
public int getNSplitter() e$~[\ w  
{ wo@ T@Ve~  
return nSplitter; OD8 fn  
} aFTWzz  
QF>T)1&J[7  
&*v\t\]  
public void setNSplitter(int nCount) &en. m>9,  
{ O&l4/RtQ\)  
nSplitter = nCount; TDH^x1P  
} ~7 i{~<?  
} JIySe:p3  
^ }7O|Y7  
A8m06  
/* f!'i5I]  
**Utility.java fp [gKRSF  
*/ 4'O,xC  
package NetFox; ?9~^QRLT  
?\o~P  
Xq135/d  
public class Utility { cwmS4^zt8  
~XOmxz0  
v #+ECx  
public Utility() tAv3+  
{ I\mF dE  
QC+ Z6WS;  
/JR+WmO  
} 5NhFjPETr  
hN3FH# YO  
//线程睡眠 Y ^+x<  
public static void sleep(int nSecond)  (Q8!5s  
{ Q4u.v,sE  
try{ &e^;;<*w  
Thread.sleep(nSecond); ` s7pM  
} 0ID9=:J  
catch(Exception e) \FsA-W\X  
{ 8US#SI'x  
e.printStackTrace (); #gC [L=01  
} Dj\nsc@e3  
} yNI0Do 2  
`Z;Z^c  
//日志 k6b ct@7  
public static void log(String sMsg) \bARp z?a  
{ l'"nU6B&  
System.err.println(sMsg); Blxa0&3  
} z=>fBb>w7  
a}y b~:TC  
gv`_+E{P  
public static void log(int sMsg) *V2;ds.~  
{ Q a (Sb  
System.err.println(sMsg); z8X7Y >+SA  
} a`' >VCg  
} |]< 3cW+  
YmC}q20;  
z x-[@G  
/* ]d1'5F][H  
**TestMethod.java -qP)L;n  
*/ uyYV_Q0~;  
package NetFox; Q4cCg7|0  
;oOTL'Vu  
YZf{."Opj[  
public class TestMethod { XM:BMd|  
vFk@  
u !BU^@P  
public TestMethod() 1 m'.wh|  
{ ///xx/weblogic60b2_win.exe hi"C<b.  
try{ 0Q{lyu  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ,?8a3%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TQ(q [:>  
SiteFileFetch fileFetch = new SiteFileFetch(bean); %tVU Rj  
fileFetch.start(); (,I:m[0  
} 21v--wZ  
catch(Exception e){e.printStackTrace ();} 4!/QB6  
?,$:~O* w  
d~<$J9%  
} ;KQU% k$  
S(PV*e8  
J@-'IJ  
public static void main(String[] args) )]fiyXA  
{ -YQh F;/  
new TestMethod(); b\"F6TF:  
} 6:2*<  
} "p O  
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