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http断点续传简单实现(java)

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/* a@}A;y'd  
**SiteFileFetch.java Z0Df~ @  
*/ HL34pmc  
package NetFox; CH4 ~9mmE  
import java.io.*; Y!nxHRE  
import java.net.*; ! C|VX,w  
gy6Pf4Yo  
t-3y`31i.  
public class SiteFileFetch extends Thread { 7qT>wCVT  
1:VbbOu->V  
TaTs-]4  
SiteInfoBean siteInfoBean = null; //文件信息Bean kZJ.G  
long[] nStartPos; //开始位置 )ND%MYJSq  
long[] nEndPos; //结束位置 g}Esj"7  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 P8=!/L2?  
long nFileLength; //文件长度 l4smAT  
boolean bFirst = true; //是否第一次取文件 ExJexjOWI^  
boolean bStop = false; //停止标志 ~.L\f%<  
File tmpFile; //文件下载的临时信息 WC *e#QP  
DataOutputStream output; //输出到文件的输出流 '980.  
NB[(O#  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) L-QzC<[F/  
public SiteFileFetch(SiteInfoBean bean) throws IOException ;!H|0sv  
{ b$k|D)_|  
siteInfoBean = bean; rXG?'jN  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )[d>?%vfd  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "l.1 UB&  
if(tmpFile.exists ()) 41Htsj  
{ >4@/x{{  
bFirst = false; L6E8A?>5rD  
read_nPos(); #I] ^Wo  
} -`<KjS  
else i |IG  
{ Mpu8/i gX,  
nStartPos = new long[bean.getNSplitter()]; yo@S.7[/  
nEndPos = new long[bean.getNSplitter()]; U-0A}@N  
} ^;=L|{Xl  
r[Zg$CW  
oGXndfd"  
oP 4z>  
} M9scZuj  
WjVj@oC  
mf\eg`'4?  
public void run() (@"5:M  
{ H(WRm1i"G  
//获得文件长度 D`C#O 7.N  
//分割文件 TE!+G\@  
//实例FileSplitterFetch D<:J6W7]  
//启动FileSplitterFetch线程 ::eYd23  
//等待子线程返回 jDwLzvM O  
try{ 3HI- G.]hC  
if(bFirst) 32KL~32Y  
{ UoSzxL  
nFileLength = getFileSize(); i9 Tq h  
if(nFileLength == -1) W`2Xn?g  
{ Y&JK*d  
System.err.println("File Length is not known!"); V.U9Q{y"  
} rjLPX  
else if(nFileLength == -2) ;%_s4  
{ F:B 8J4/  
System.err.println("File is not access!"); BJ,9C.|  
} @fz!]/  
else H$o=kQN  
{ {Z^  G]@  
for(int i=0;i<nStartPos.length;i++) ^^C@W?.z  
{ yl'@p 5n  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Y!C8@B$MR3  
} 4>I >y@^  
for(int i=0;i<nEndPos.length-1;i++) ^w(~gQ6|mP  
{ okv`+VeA  
nEndPos = nStartPos[i+1]; <yq kJ  
} ]`,jaD  
nEndPos[nEndPos.length-1] = nFileLength; ~R!M.gY[rK  
} y +2  
} |{en) {:  
FC BsC#  
4`M7 3k0  
//启动子线程 #lld*I"d  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; b)1v:X4Bv=  
for(int i=0;i<nStartPos.length;i++) F\G-. 1  
{ HZDeQx`*s  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +t hkx$o  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $ /p/9 -  
nStartPos,nEndPos,i); k~,({T<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ! O~:  
fileSplitterFetch.start(); 2/ES.>K!.  
}  <RaM@E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZJ Ke}F`l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?n0Z4 8%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", l1?$quM^V  
nEndPos = " + nFileLength); b2<((H  
// fileSplitterFetch[nPos.length-1].start(); P56B~M_  
Uzzt+Iwm  
<QcQ.b  
//等待子线程结束 .nG14i7C  
//int count = 0; a(Fx1`}  
//是否结束while循环 v%2@M  
boolean breakWhile = false; rUL_=>3  
AIU=56+I\  
:kb2v1{\  
while(!bStop) xxS>O%  
{ }#Gq*^w  
write_nPos(); 1](PuQm7+  
Utility.sleep(500); kQt#^pO)  
breakWhile = true; ><Awk~KR  
3<%ci&B  
^_rBEyz@  
for(int i=0;i<nStartPos.length;i++) Nm.G,6<J  
{ yPXa  
if(!fileSplitterFetch.bDownOver) K}j["p<!  
{ aB*'DDlx"r  
breakWhile = false; wdo(K.m  
break; 99G'`NO  
} gL(_!mcwu  
} ]o<&Q52|  
if(breakWhile) |T)  $E  
break; =Sp+$:q*  
92 oUQ EK  
q4y sTm  
//count++; )kpNg:2p  
//if(count>4) $3'xb/3|  
// siteStop(); W_bp~Wu  
} uG){0%nX  
qOs'Ljx6l  
\Aq$h:<  
System.err.println("文件下载结束!"); Zb4+zps^-  
} o6Jhl8  
catch(Exception e){e.printStackTrace ();} z55g'+Kab  
} &)ED||r,  
E gD$A!6N8  
F>lM[Lu#  
//获得文件长度 :6[G;F7s  
public long getFileSize() 5 !Ho[  
{ !+V."*]l  
int nFileLength = -1; D_)N!,i  
try{ !(8) '<t9  
URL url = new URL(siteInfoBean.getSSiteURL()); IDK~ (t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Xf%vfAf  
httpConnection.setRequestProperty("User-Agent","NetFox"); $No^\.mV  
>*]dB|2  
yE_T#FN  
int responseCode=httpConnection.getResponseCode(); UY}EW`$#m  
if(responseCode>=400) VYw<8AEFY  
{ k((kx:  
processErrorCode(responseCode); m>{I>:sq  
return -2; //-2 represent access is error 1/tyne=m  
} <Eu/f`8  
uGU-MC *  
>v'@p  
String sHeader; Z/e^G f#i  
%$6?em_  
cES8%UC^i  
for(int i=1;;i++) EL^j}P  
{ B".3NQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9 K~X+N\  
//Utility.log(in.readLine()); E0*62OI~O  
sHeader=httpConnection.getHeaderFieldKey(i); cof+iI~9O%  
if(sHeader!=null) Ie7S'.Lmq  
{ q${+I(b,  
if(sHeader.equals("Content-Length")) n3_| # 1Qu  
{ 49tJ+J-N  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); A)80qx:  
break; Uo0[ZsFD  
} =: =s  
} iit 5IV  
else &~'^;hy=  
break; kk$D:UQX  
} )u=46EU_  
} 9|l6.$Me/  
catch(IOException e){e.printStackTrace ();} d04fj/B  
catch(Exception e){e.printStackTrace ();} UWW'[gEP1  
v`\CzT  
Mt*eC)~ Yx  
Utility.log(nFileLength); 2v{42]XYf  
sB=s .`9  
C {G647  
return nFileLength; l(Y\@@t1  
} X3j|J/  
MUi#3o\f  
9/PX~j9O?  
//保存下载信息(文件指针位置) d;g]OeF  
private void write_nPos() S9E<)L  
{ p>1Klh:8.'  
try{ |[iEi  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *t bgIW+h  
output.writeInt(nStartPos.length); 7b*9 Th*a  
for(int i=0;i<nStartPos.length;i++) L.x`Jpq(3  
{ + %H2;8{F  
// output.writeLong(nPos); `,s0^?_  
output.writeLong(fileSplitterFetch.nStartPos); Mi<}q@]e  
output.writeLong(fileSplitterFetch.nEndPos); V;(Rg=5  
} Z|BOuB^   
output.close(); 9Idgib&  
} o@qI!?p&  
catch(IOException e){e.printStackTrace ();} `^: v+!  
catch(Exception e){e.printStackTrace ();} F> b<t.yV  
} %:.IG.`d  
q9B5>Ye)  
g>n1mK|  
//读取保存的下载信息(文件指针位置) K_}81|=  
private void read_nPos() ^:2>I$  
{ b4CXif  
try{ /rnP/X)T  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); R_duPaWc@  
int nCount = input.readInt(); X=[`+=  
nStartPos = new long[nCount]; oR}'I  
nEndPos = new long[nCount]; vFK!LeF%  
for(int i=0;i<nStartPos.length;i++) =`t%p1   
{ t]6 4=  
nStartPos = input.readLong(); )%bY2 pk  
nEndPos = input.readLong(); 6BObV/S Jg  
} l-q.VY2  
input.close(); / jN &VpDG  
} zJTSg  
catch(IOException e){e.printStackTrace ();} Dw&_6\F@  
catch(Exception e){e.printStackTrace ();} 3gz4c1 s^:  
} }b / G{92  
fH 0&Wc3yC  
WZf}1.Mh*  
private void processErrorCode(int nErrorCode) `_E@cZ4  
{ fYzZW  
System.err.println("Error Code : " + nErrorCode); ,,~|o3cfq  
} ^fhkWx4i  
Ombvp;  
h"(HDnq  
//停止文件下载 }O8#4-E_Ji  
public void siteStop() Os)}kkja  
{ ^w~Utx4  
bStop = true; ;mXw4_{  
for(int i=0;i<nStartPos.length;i++) |\/V1  
fileSplitterFetch.splitterStop(); !z_VwZ#,  
5uD'Kd$H  
J-Wphc!m  
} FQw@ @  
} \"Aw ATQ  
//负责部分文件的抓取 3t$)saQR  
**FileSplitterFetch.java *h2)$^P%  
*/ #6za  
package NetFox; (\ Gs7  
^vr`t9EE  
> 72qi*0  
import java.io.*; N}7tjk   
import java.net.*; #3((f[  
YojYb]y+ j  
nX-%qc"  
public class FileSplitterFetch extends Thread { B#K2?Et!t  
J@Qw6J  
psAdYEGk!  
String sURL; //File URL :a y-2  
long nStartPos; //File Snippet Start Position qb$f,E[  
long nEndPos; //File Snippet End Position j~`rc2n%  
int nThreadID; //Thread's ID k?ksv+e\  
boolean bDownOver = false; //Downing is over KHt.g`1:R  
boolean bStop = false; //Stop identical (C!33s1  
FileAccessI fileAccessI = null; //File Access interface /@f3|L<1@V  
Pt8 U0)i)  
Xw<Nnvz6  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "~aCW~  
{ X5wYfN  
this.sURL = sURL; Wj#Gm  
this.nStartPos = nStart; AE&IN.-  
this.nEndPos = nEnd; }|4dEao\  
nThreadID = id; jl~?I*Gr  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &ajpD sz;  
} ($Y6hn+  
a%)-iL X8&  
"ju0S&  
public void run() R{A$hnhW6  
{ t"]~e"  
while(nStartPos < nEndPos && !bStop) %2TjG  
{  XV*uu "F  
tS&rR0<OW  
mLL?n)   
try{ J;cTEB  
URL url = new URL(sURL); V-%Am  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); gTwxmp.,  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5b-: e? |  
String sProperty = "bytes="+nStartPos+"-"; m\?H < o0  
httpConnection.setRequestProperty("RANGE",sProperty); cQldBc  
Utility.log(sProperty); l]v>PIh~N  
BjIKs~CT  
KsBi<wY  
InputStream input = httpConnection.getInputStream(); Z4@GcdZ  
//logResponseHead(httpConnection); *WpDavovyB  
E0a &1j  
s6J`i&uu  
byte[] b = new byte[1024]; 8^%Nl `_2B  
int nRead; isR|K9qf^  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '{xPdN  
{ #iAEcC0k5  
nStartPos += fileAccessI.write(b,0,nRead); Wf>scl `s  
//if(nThreadID == 1) o$_,2$>mn  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); TEi~X 2u  
} B M$+r(#t  
`t~Zkb4>  
J)leRR&  
Utility.log("Thread " + nThreadID + " is over!"); )Y}8)/Pud  
bDownOver = true; 9 WhZ= Xk  
//nPos = fileAccessI.write (b,0,nRead); #DFfySH)A  
} OFe?T\dQn  
catch(Exception e){e.printStackTrace ();} `@07n]KB  
} #0;ULZ99aH  
} yxz"9PE/P  
dCkk5&2n  
PhOtSml0  
//打印回应的头信息 y,QJy=?  
public void logResponseHead(HttpURLConnection con) 0xQ="aXE  
{ I@<\DltPi  
for(int i=1;;i++) /"%(i#<)xs  
{ "`4V ^1  
String header=con.getHeaderFieldKey(i); bI"_hvcFp  
if(header!=null) \tx4bV#  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); v8!Ts"  
Utility.log(header+" : "+con.getHeaderField(header)); QBI;aG<+b>  
else ,aBo p#  
break; >=Pn\" j  
} :v>Nz7SB  
} t}]R0O.s  
qoXncdDHZ  
^yo~C3 r~  
public void splitterStop() >MeM  
{ n6Qsug$z  
bStop = true; ^$I8ga  
} ckTk2xPQ  
1SGLA"r  
c_#+xGS!7  
} MQ{.%  
o6[aP[~F  
V"`t*m$  
/* at-+%e  
**FileAccess.java z[`O YwsW  
*//文件访问(定位,写) (7Q Fy  
package NetFox; vRQ7=N{3  
import java.io.*; ',Q|g^rF]  
NP#:} )  
%P2l@}?a  
public class FileAccessI implements Serializable{ $)O=3dNbo  
q&RezHK l  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C6T?D5  
RandomAccessFile oSavedFile; T7bD t  
long nPos; b&j}f  
RU_wr<  
9_  
public FileAccessI() throws IOException +xc1cki_{  
{ 0<";9qN)6  
this("",0); NM{/rvM  
} iUua!uC  
(Iz$_(  
;"K;D@xzh]  
public FileAccessI(String sName,long nPos) throws IOException %7y8a`}  
{ zG. \xmp  
oSavedFile = new RandomAccessFile(sName,"rw"); ym =7EY?o  
this.nPos = nPos; Y%1 94fY$  
oSavedFile.seek(nPos); -0>gq$/N=^  
} }@XokRk  
JE<w7:R&  
Sbp].3^j  
public synchronized int write(byte[] b,int nStart,int nLen) W:gpcR]>  
{ fZ5zsm'N  
int n = -1; nde_%d$  
try{ W Y]   
oSavedFile.write(b,nStart,nLen); +\_c*'K>  
n = nLen; 6B=: P3Y  
} h7"c_=w+  
catch(IOException e) j*' +f~ A  
{ p"UdD  
e.printStackTrace (); L<62-+e`  
} o<8('j   
e>] gCa  
=+z+`ot  
return n; Z.l4<  
} S<Os\/*  
w$##GM=Tq  
A 6IrA/b  
} bQlvb  
LN0pC }F  
/L yoTBG  
/* BtA_1RO  
**SiteInfoBean.java Rl/5eE8  
*/ 5w+KIHhN|  
package NetFox; r&y0`M  
{KGEv%  
uSgR|b;R]  
public class SiteInfoBean { iLC.?v2=  
8=  kwc   
?l9j]  
private String sSiteURL; //Site's URL -Is;cbfLj/  
private String sFilePath; //Saved File's Path !y\r.fm!A  
private String sFileName; //Saved File's Name L}a-c(G+8  
private int nSplitter; //Count of Splited Downloading File &pzf*|}  
}NJKkj?  
'w z6Zt  
public SiteInfoBean() QJ,[K _  
{//nSplitter的缺省值为5 5(=5GkE)>  
//default value of nSplitter is 5 9,wD  
this("","","",5); 4^Y{ BS fF  
} 7M/v[dwL  
m!K`?P]:N  
('k9XcTPP  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 9?XQB%44  
{ 4=~+B z  
sSiteURL= sURL; n "bii7h  
sFilePath = sPath; #PkZi(k hv  
sFileName = sName; [} zzG@g,J  
this.nSplitter = nSpiltter; l@)`Q  
8g0VTY4$jP  
r@a]fTf  
} YO'aX  
bEKhU\@=J  
%b[>eIJU#  
public String getSSiteURL() 21$E.x 6  
{ nSv@FT'~z  
return sSiteURL; D"V(A\sZ  
} 7tbY>U8  
vc0LV'lmg  
uc>":V  
public void setSSiteURL(String value) ; I;&O5Y  
{ SF=TG84<  
sSiteURL = value; $niG)@*  
} Kr5(fU  
AP:Q]A6}  
I`f5)iF?0  
public String getSFilePath() O joa3  
{ ]t0St~qUL)  
return sFilePath; J%u,qF}h  
} 'Qh1$X)R7a  
T-LX>*  
j'k <  
public void setSFilePath(String value) jsFfrS"*  
{ jF}-dfe  
sFilePath = value; L^jjf8_  
} "Ccyj/  
%s! |,Cu  
H76iBJ66  
public String getSFileName() s IFE:/1,  
{ g<N;31:c\  
return sFileName; e\em;GTy  
} .* )e24`  
.P <3+  
byFO^pce  
public void setSFileName(String value)  l*?_@  
{ Z]e`bfNnI  
sFileName = value; +Bf?35LP  
} s&hr$`V4  
lA pZC6Iwk  
P8(hHuO  
public int getNSplitter() wRvh/{xB  
{ =EYWiK77a  
return nSplitter; z2>LjM) #  
} [l3ys  
$nb.[si\  
6w=`0r3hy  
public void setNSplitter(int nCount) n y cn  
{ <iA\ZS:  
nSplitter = nCount; %q}[ZD/HD  
} /w1M%10   
} q3<kr<SP  
En:>c  
6`@b@Kd  
/* F"bz<{  
**Utility.java =?c""~7  
*/ hrm<!uKn  
package NetFox; =ecLzk"+F  
e P,bFc  
"M, 1ElQ  
public class Utility { $~S~pvT  
~nTj't2R  
kU+|QBA@  
public Utility() L R\LC6kM  
{ drMMf[  
(6.uNLr  
z&WtPSyGj  
} 'zM=[#!B  
[}YUi>NGA  
//线程睡眠 Q6W![571;  
public static void sleep(int nSecond) i!zFW-*5  
{ 8L,=Eap  
try{ FieDESsX>  
Thread.sleep(nSecond); >MGWN  
} c} +*$DeT  
catch(Exception e) *5 +GJWKN  
{ g@37t @I  
e.printStackTrace (); <|3%}?  
} P`ou:M{8  
} . %s U)$bH  
~_-]> SI  
//日志 jM&di  
public static void log(String sMsg) ;F#(:-:  
{ F~8'3!<9  
System.err.println(sMsg); R0}1:1}$Sn  
} WFiX=@SS  
s(nT7x+W  
b,^Gj]7  
public static void log(int sMsg) 'Y/0:)  
{ O5:bdt.  
System.err.println(sMsg); Z(7kwhP[`  
} g_1#if&  
} <(q(5jG  
 ]'`E  
m/1FVC@*  
/* b?l>vUgAg  
**TestMethod.java GPGE7X'  
*/ 0muC4  
package NetFox; B ytx.[zbX  
{Q3OT  
+?Ii=*7n  
public class TestMethod { eD?&D_l~6  
1!KROes4  
~PI2G 9  
public TestMethod() 9H/>M4RT  
{ ///xx/weblogic60b2_win.exe f4h~c  
try{ R7/S SuG6\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Xva(R<W7d<  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ts!tv6@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .P$m?p#  
fileFetch.start(); oGRk/@  
} -BH/)$-$  
catch(Exception e){e.printStackTrace ();} ;NR|Hi]  
A<ds+0  
uYMn VE"  
} Xj 1Oxm 42  
:YI5O/gsk?  
=3 .dgtH  
public static void main(String[] args) 393c |8M  
{ "5&"Ij,/  
new TestMethod(); ^o{{kju  
} tL$,]I$1+  
} 0+e=s0s.  
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