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http断点续传简单实现(java)

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/* 7P& O{tl(  
**SiteFileFetch.java |OgtAI9  
*/ :A~6Gk92A  
package NetFox; 3RwDIk?>%  
import java.io.*; (%bqeI!ob  
import java.net.*; Cb`2"mpWS  
td}%reH  
OMl<=;^:|  
public class SiteFileFetch extends Thread { 8ZnHp~  
Ys+2/>!  
jrF#DDH?I  
SiteInfoBean siteInfoBean = null; //文件信息Bean HDV@d^]-  
long[] nStartPos; //开始位置 )<<}8Fs  
long[] nEndPos; //结束位置 a9+l :c@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 M%U1?^j8  
long nFileLength; //文件长度 ;ui=7[ Us  
boolean bFirst = true; //是否第一次取文件 q6A"+w,N  
boolean bStop = false; //停止标志 Ct8}jg"  
File tmpFile; //文件下载的临时信息 lhp.zl  
DataOutputStream output; //输出到文件的输出流 &8w MGahp  
\& KfIh8  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) vXq2="+  
public SiteFileFetch(SiteInfoBean bean) throws IOException ./Y5Vk#Rp\  
{ =!?4$vW  
siteInfoBean = bean; 4s <|8   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); AA&5wDMV>  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); eu^B  
if(tmpFile.exists ()) .huk>  
{ rAuv`.qEV  
bFirst = false; t XbMP  
read_nPos(); 4^OPzg6Z%p  
} x_k @hGSC  
else [k<w'n*  
{ n _H]*~4F  
nStartPos = new long[bean.getNSplitter()]; )C1ihm!7\  
nEndPos = new long[bean.getNSplitter()]; $-J=UT2m  
} ]b&"](A  
%F.^cd"  
?gGmJl  
u/,ng&!  
} x&['g*[L0  
P c'0.4  
H[;\[ 3  
public void run() W["c3c  
{  mRYM,   
//获得文件长度 }Q<c E$c  
//分割文件 sf(2~BMQI  
//实例FileSplitterFetch iN]#XIQ%  
//启动FileSplitterFetch线程 $z":E(oy  
//等待子线程返回 !^h{7NmP[  
try{ =0" Zse,  
if(bFirst) NZaMF.  
{  FTk`Mq  
nFileLength = getFileSize(); tl@n}   
if(nFileLength == -1) Bq# l8u  
{ ^5,B6  
System.err.println("File Length is not known!"); Zf [#~4  
} j3kcNb  
else if(nFileLength == -2) ^5-8'9w  
{  0+P[0  
System.err.println("File is not access!"); y wf@G; fK  
} )=EJFQ*v  
else 'U %L\v,  
{ +Vsd%AnN"l  
for(int i=0;i<nStartPos.length;i++) |."thTO  
{ Ga9^+.j  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); &|j^?ro6  
} \'}? j-8  
for(int i=0;i<nEndPos.length-1;i++) z}sBx 9;  
{ 3R|C$+Sc  
nEndPos = nStartPos[i+1]; A"PmoV?lAm  
} !JOM+P:  
nEndPos[nEndPos.length-1] = nFileLength; <lxE^M  
} p0b2n a !  
} `N,q~@gL  
3ug-cq  
+:#x!i;W8[  
//启动子线程 Jd0I!L  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; pZA0Go2!IN  
for(int i=0;i<nStartPos.length;i++) .V.x0  
{ \A'tV/YAd  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N7WQ{/PSG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9}_ccq  
nStartPos,nEndPos,i); }vGW lNd#g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j1 Q"s(  
fileSplitterFetch.start(); FLE2]cL-  
} ='"hB~[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <JyF5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <Jwx|  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @UG%B7  
nEndPos = " + nFileLength); ow!NH,'Hy  
// fileSplitterFetch[nPos.length-1].start(); /ivA[LSS  
k9|8@3(h  
BIM!4MHLA  
//等待子线程结束 (TjY1,f!H  
//int count = 0; {*jo,<4ee  
//是否结束while循环 2U Q&n`A  
boolean breakWhile = false; d2!A32m  
8qi6>}A  
F CbU> 1R  
while(!bStop) $afE= qC*  
{ &0='z  
write_nPos(); ~s[St0  
Utility.sleep(500); 1m5 =Nu  
breakWhile = true; ff3HR+%M  
?8O %k<?  
+"HLx%k  
for(int i=0;i<nStartPos.length;i++) A/%+AH(  
{ X4bB  
if(!fileSplitterFetch.bDownOver) Q-qM"8I  
{ F ^mMyK  
breakWhile = false; `]q>A']Dl  
break; !B#Lea  
} IB sQaxt.  
} 0';U3:=i,  
if(breakWhile) -hpJL\ng  
break; a1 I"Sh  
u*aFWl]=  
ha%3%O8Z  
//count++; Y@+e)p{  
//if(count>4) BJ]4j-^o  
// siteStop(); ^zv,VD  
} _2wU(XYH  
+-VkRr#  
S S/9fT"[  
System.err.println("文件下载结束!"); +] .Zs<  
} x P3v65Q1  
catch(Exception e){e.printStackTrace ();} $Eo)i  
} + \DGS  
ZP]l%6\.  
~; emUU  
//获得文件长度 \R6D'Yt  
public long getFileSize() ep<O?7@j-G  
{ Yb~[XS |p  
int nFileLength = -1; ?_!} lg  
try{ # -0}r  
URL url = new URL(siteInfoBean.getSSiteURL()); *G<K@k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '\&t3?;  
httpConnection.setRequestProperty("User-Agent","NetFox"); w=UFj  
s Y^#I  
\5MW65  
int responseCode=httpConnection.getResponseCode(); xUiSAKrcM  
if(responseCode>=400) M_5$y )M  
{ VdVUYp  
processErrorCode(responseCode); E%?X-$a  
return -2; //-2 represent access is error K%+[2Hj2  
} O,&nCxB]  
x8#bd{  
SnK#YQCDt  
String sHeader; ?gp:uxq,.  
"M)kV5v%  
ot"3 3I  
for(int i=1;;i++) ) r8yt}  
{ (iwZs:k-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); IfK%i/J  
//Utility.log(in.readLine()); u~WE} VC  
sHeader=httpConnection.getHeaderFieldKey(i); <6 LpsM}  
if(sHeader!=null) BrWo/1b  
{ 'zEmg}  
if(sHeader.equals("Content-Length")) J6WyFtlyLc  
{ c v .R`)l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^#-i%V%  
break; z1-JoZ  
} (?G?9M#7_  
} %Sgdhgk1  
else *J ]2"~_.  
break; #J=@} S)  
} nB; yS<  
} u%o2BLx  
catch(IOException e){e.printStackTrace ();} =54"9*  
catch(Exception e){e.printStackTrace ();} )A@i2I  
_P^ xX'v  
d x/NY1  
Utility.log(nFileLength); w7(jSPB  
I6q]bQ="  
<~rf;2LZ  
return nFileLength; ._6|epJ#  
} 55mDLiA  
-Um|:[*I  
w9Eb\An  
//保存下载信息(文件指针位置) myR}~Cj;q  
private void write_nPos() rJ@yOed["b  
{ shn{]Y  
try{ e >OYJd0s  
output = new DataOutputStream(new FileOutputStream(tmpFile)); OdZLJt?g  
output.writeInt(nStartPos.length); /]_a\x5Ss  
for(int i=0;i<nStartPos.length;i++) q h+c}"4m  
{ @CxXkR  
// output.writeLong(nPos); 2l8TX#K  
output.writeLong(fileSplitterFetch.nStartPos); b <1k$0J6  
output.writeLong(fileSplitterFetch.nEndPos); KMhEU**  
} )|Ho"VEmg  
output.close(); YFGQPg  
} N ?RJuDW  
catch(IOException e){e.printStackTrace ();} Q#,j,h  
catch(Exception e){e.printStackTrace ();} "!fvEE  
} 6F@2:]W  
k~ YZT 8  
"G(^v?x:P  
//读取保存的下载信息(文件指针位置) ThvVLK  
private void read_nPos() Q9\6Pn ]T  
{ f`[gRcZ-  
try{ B?-~f^*,jG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); x+X^K_*  
int nCount = input.readInt(); B!z-O*fLE1  
nStartPos = new long[nCount]; +1R qo  
nEndPos = new long[nCount]; " iKX-VIl  
for(int i=0;i<nStartPos.length;i++) f<Co&^A  
{ x c[BQ|P=  
nStartPos = input.readLong(); MgP6ki1z  
nEndPos = input.readLong(); >_<J=8|E  
} UImd* ;2TE  
input.close(); =$^<@-;  
} :J'ibb1  
catch(IOException e){e.printStackTrace ();} 9uRs@]i  
catch(Exception e){e.printStackTrace ();} Hf ]w  
} -%h0`hOG{  
}+" N '  
.QaHE`e{  
private void processErrorCode(int nErrorCode) !OO{qw(*g  
{ 9AbSt&#  
System.err.println("Error Code : " + nErrorCode); hZudVBn  
} VgoN=S  
EZz`pE  
\k8|3Y~g  
//停止文件下载 x;G~c5  
public void siteStop() Gz>M`M`[4  
{ oI!L2  
bStop = true; LvtZZX6!  
for(int i=0;i<nStartPos.length;i++) ;M95A  
fileSplitterFetch.splitterStop(); H/eyc`  
XHN`f#(w  
+Yuy%VT  
} H"_]Hq  
} 77:s=)   
//负责部分文件的抓取 T{L{<+9%  
**FileSplitterFetch.java CQLh;W`Dc  
*/ 1o;*`  
package NetFox;  F%}0q&  
icX$<lD  
0Q]p#;  
import java.io.*; ~[|zf*ZISG  
import java.net.*; NWGSUUa  
zeXMi:X  
Fe4QWB6\U  
public class FileSplitterFetch extends Thread { ${/"u3a_  
C&\vVNV;9  
6iozb~!Rr  
String sURL; //File URL S[J=d%(  
long nStartPos; //File Snippet Start Position +dkbt%7M  
long nEndPos; //File Snippet End Position *L%i-Wg"  
int nThreadID; //Thread's ID \/jr0):  
boolean bDownOver = false; //Downing is over 5Wj+ey^ ^w  
boolean bStop = false; //Stop identical \TG!M]D:  
FileAccessI fileAccessI = null; //File Access interface l`2X'sw[/  
29"eu#-Qj  
?Z@FxW  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /Yk2 |L  
{ '0|AtO77  
this.sURL = sURL; %/dYSC  
this.nStartPos = nStart; NyD[9R?  
this.nEndPos = nEnd; i0uBb%GMT  
nThreadID = id; \ ?[#>L4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %zHNX4  
} h<.G^c)  
,\;;1Kq  
L!E/ )#{  
public void run() +dm&XW >  
{ c'_-jdi`>_  
while(nStartPos < nEndPos && !bStop) %T*lcg  
{ d"+zDc;  
rt%.IQdY  
m?-3j65z  
try{ - Z"w  
URL url = new URL(sURL); c/ wzV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); L0SeG:  
httpConnection.setRequestProperty("User-Agent","NetFox"); > _U)=q  
String sProperty = "bytes="+nStartPos+"-"; /%Bc*k=ox  
httpConnection.setRequestProperty("RANGE",sProperty); "U34D1I )#  
Utility.log(sProperty); n.C.th >Y1  
e*uaxh+7  
\)VV6'zih  
InputStream input = httpConnection.getInputStream(); m~~_iz_*  
//logResponseHead(httpConnection); buGW+TrWY  
1TfK"\  
p5^,3&  
byte[] b = new byte[1024]; ~$>l@> xX  
int nRead; k oo`JHC  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) q{ov62t`  
{ < vU<:S  
nStartPos += fileAccessI.write(b,0,nRead); V\@h<%{^%7  
//if(nThreadID == 1) @D8c-`LC"*  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o)'T#uK  
} x^}kG[s  
,#&lNQ'I  
>z6 (fM`i  
Utility.log("Thread " + nThreadID + " is over!"); 7]Y Le+Ds  
bDownOver = true; Eom|*2vWIC  
//nPos = fileAccessI.write (b,0,nRead); .ps'{rl8  
} ;rpjXP  
catch(Exception e){e.printStackTrace ();} pt;E~_  
} b9[;qqq@'  
} !v^D}P 3Y  
8Cz_LyL  
+T=Z!2L  
//打印回应的头信息 8 s!0Z1Roc  
public void logResponseHead(HttpURLConnection con) E\#hcvP  
{ LF <fp&C)h  
for(int i=1;;i++) aOfL;I  
{ T5NO}bz  
String header=con.getHeaderFieldKey(i); g5R2a7  
if(header!=null) [=9-AG~}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /ZZo`   
Utility.log(header+" : "+con.getHeaderField(header)); j]}A"8=1  
else [wP;g'F  
break; 2}>jq8Y47  
} `h_,I R<  
} NY\q  
|r1\  
vG O-a2Z  
public void splitterStop() @Z~lM5n$8  
{ -EFtk\/  
bStop = true; }rsD$  
} q17c)]<"  
P %f],f  
Oga0CR_  
} $[5ihV$u  
< i"U%Ds(  
,x!P|\w.G{  
/* 9kL'"0c  
**FileAccess.java /8@JWK^I{  
*//文件访问(定位,写) k'}}eu/ q  
package NetFox; T[B@7$Dp*  
import java.io.*; T j9;".  
JLm0[1Lzd  
v5i[jM8  
public class FileAccessI implements Serializable{ L.>tJ.ID  
OaRtGJnR  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 PcC9)x  
RandomAccessFile oSavedFile; AJ`b- $Q  
long nPos; :X Er{X  
 =\`g<0  
E.Xf b"]  
public FileAccessI() throws IOException VS@o_fUx)  
{ /=>z|?z3  
this("",0); %h 6?/  
} 7lY&/-V  
HT)b3Ws~M8  
&N GYV  
public FileAccessI(String sName,long nPos) throws IOException sguE{!BO  
{ 2;r(?ebw  
oSavedFile = new RandomAccessFile(sName,"rw"); EMzJJe{Cv  
this.nPos = nPos; 1U.se` L  
oSavedFile.seek(nPos); )(TaVHJR  
} ]S<eO6z  
frbKi _1  
]24aK_Uu  
public synchronized int write(byte[] b,int nStart,int nLen) 5t#+UR  
{ &G7JGar  
int n = -1; "{105&c\  
try{ LOpn PH`  
oSavedFile.write(b,nStart,nLen); ?Q[uIQ?dV  
n = nLen; z8{ kwz  
} N~ _GJw@  
catch(IOException e) |8PUmax  
{ <KqZ.7XfB  
e.printStackTrace (); _HX 1E  
} `4__X;  
~Wjm"|c  
wv<D%nF2|  
return n; D% } ?l  
} uFOxb}a9v  
/R^Moj<  
6js94ko[  
} ^5j|   
_"SE^_&c  
-v .\CtpHv  
/* h 1G`z  
**SiteInfoBean.java Er^ijh,  
*/ L22GOa0  
package NetFox; :zdMV6s  
!c[(#g  
u"XqWLTV  
public class SiteInfoBean { 0"7 xCx  
MO&QR-OY  
w~+5FSdH  
private String sSiteURL; //Site's URL tp<uN~rTgh  
private String sFilePath; //Saved File's Path h 92\1,  
private String sFileName; //Saved File's Name u[9i>7}9  
private int nSplitter; //Count of Splited Downloading File l_GvdD  
VXXo\LQUU  
@-nCK Yj  
public SiteInfoBean() &M(=#pq9  
{//nSplitter的缺省值为5 :L#t?~  
//default value of nSplitter is 5 #D M%_HXDi  
this("","","",5); cZI )lX  
} gQ4Q h;  
S%gb1's  
u,e'5,`N  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) a)=WDRk  
{ \PU3{_G]  
sSiteURL= sURL; &QO~p3M  
sFilePath = sPath; u}Vc2a,WV  
sFileName = sName; FJKW=1 =,  
this.nSplitter = nSpiltter; O 4@sN=o  
$~vy,^  
HSGM&!5mW  
} R2WEPMH%  
zJJ KLr;  
Bf!i(gM  
public String getSSiteURL() #A<|&#hh  
{ <Z5ak4P  
return sSiteURL; Q<W9<&VZe  
} m<)0 XE6w  
H|_^T.n?E  
{;0j9rr  
public void setSSiteURL(String value) +;~JHx.~X  
{ `3+yu' Q'  
sSiteURL = value; U]j4Izq  
} S6-)N(3|  
1];rW`Bw  
54~`8f  
public String getSFilePath() 2GOQ|Z  
{ g+Vfd(e  
return sFilePath; #PUvrA2Zl  
} pFi.?|6"  
V\^rs41$;  
0STtwfTr:  
public void setSFilePath(String value) 3Tze`Q 9  
{ !GI*R2<W  
sFilePath = value; #g[jwl'  
} bOjvrg;Sz\  
Q4e*Z9YJ  
N: 'v^0  
public String getSFileName() fkE4 [X7f  
{ ^$qr6+  
return sFileName; v#*9rNEj0  
} H~%HTl  
<>/0 ;J1<  
 jL8[;*^G  
public void setSFileName(String value) 2[f8"'lUQ  
{ xCwd*lsM  
sFileName = value; [of{~  
} 0<*R 0  
xc)A`(g  
`tA~"J$32l  
public int getNSplitter()  O\y #|=d  
{ ,l`4)@{G  
return nSplitter; 19-|.9m(  
} @wO"?w(  
k(1]!c4J0  
QX}O{LQR  
public void setNSplitter(int nCount) 8 CKN^8E  
{ OZ 4uk.)  
nSplitter = nCount; lc1?Vd$  
} =4`#OQ&g  
} {n9]ej^  
!f5I.r~  
<)n8lIK  
/* 2eErvfC[  
**Utility.java ]q@/:I9]  
*/ ,)%al76E  
package NetFox; CVfQ  
RbB y8ZVM  
d]Y-^&]{]  
public class Utility { I3Gz,y+  
<=WSX{_D  
(iM*Y"Y  
public Utility() ioxs x>e<  
{ <aps)vF  
1.\|,$  
= 7%1]  
} j8/rd  
On%21L;JG  
//线程睡眠 hE.NW  
public static void sleep(int nSecond) I| j Gu9G  
{ l)y$c}U  
try{ +$Q.N{LV  
Thread.sleep(nSecond); CZ2&9Vb9I  
} i,HafY  
catch(Exception e) 951"0S`Lo  
{ W vh3Y,|3  
e.printStackTrace ();  N7%iz+  
} ul0]\(sS:  
} Vgy}0pCl  
E.*TJ  
//日志 bvyX(^I[q  
public static void log(String sMsg) r9!jIkILz  
{ GilaON*pK.  
System.err.println(sMsg); @C[]o.r  
} j2GO ZKy  
pfd||Z  
ZJUTtiD  
public static void log(int sMsg) Pl|e?Np  
{ OVr, {[r  
System.err.println(sMsg); Nb.AsIR^  
} z"4UObVs  
} Q-<,+[/  
0*?/s\>PS;  
4 ZD~i e  
/* _-^bAr`z  
**TestMethod.java /?<tjK' "H  
*/ C@!C='b,  
package NetFox; [x}]sT`#a  
P'Q|0lB  
h\+U+ ?u  
public class TestMethod { |e+8Xz1>  
kpc3l[.A  
63hOK  
public TestMethod() g3B zi6$m  
{ ///xx/weblogic60b2_win.exe sW/^82(dM  
try{ sTu6KMn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); F8e]sa$K\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5|l&` fv`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i <KWFF#  
fileFetch.start(); *=]hc@  
} Yh`P+L  
catch(Exception e){e.printStackTrace ();} *5( h,s3&  
T &.ZeB1  
J%|!KQl  
} QR'yZ45n4  
i:ar{ q  
]y*AA58;  
public static void main(String[] args) |eD$eZ=m  
{ D&5>Op4U  
new TestMethod(); HKA7|z9{  
} anwMG0  
} #{973~uj  
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