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http断点续传简单实现(java)

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/* Spm7kw  
**SiteFileFetch.java aEvW<jHh  
*/ Mq,2S  
package NetFox; tH^]`6"QUa  
import java.io.*; fnZ?YzLI  
import java.net.*; 1/J3 9Y~+  
zg+6< .Sf  
X Z4q{^o  
public class SiteFileFetch extends Thread { chs] ,7R  
=4_Er{AT  
S( Vssi|y  
SiteInfoBean siteInfoBean = null; //文件信息Bean ~|kSQ7O^  
long[] nStartPos; //开始位置 efUa[XO  
long[] nEndPos; //结束位置 'fS&WVR?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B$D7}=|kc  
long nFileLength; //文件长度 <4%cKW0  
boolean bFirst = true; //是否第一次取文件 <!G%P4)  
boolean bStop = false; //停止标志 `E:&a]ul  
File tmpFile; //文件下载的临时信息 x3tos!Y  
DataOutputStream output; //输出到文件的输出流 }_|qDMk+  
5!jU i9  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) DU|>zO%  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,.,spoV  
{ zbgH}6b  
siteInfoBean = bean; V*j1[d  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); U@:h';.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0 qp Pz|h  
if(tmpFile.exists ()) MfG8=H2#|  
{ >j6"\1E+Dz  
bFirst = false; peD7X:K\s  
read_nPos(); <Gw>}/-^  
} oa<%R8T?@  
else k^ Qd%;bdF  
{ .g?Ppma  
nStartPos = new long[bean.getNSplitter()]; a1 v%G  
nEndPos = new long[bean.getNSplitter()]; vlVHoF;&  
} `NB6Of*/  
vp&N)t_  
U>0~/o  
# ~(lY}  
} M.u1SB0  
34c+70x7  
_ZHDr[  
public void run() 0u?Vn N<  
{ Dj9ecV`  
//获得文件长度 vB Vg/  
//分割文件 /K :H2?J  
//实例FileSplitterFetch F#KUu3;B  
//启动FileSplitterFetch线程 )~be<G( a  
//等待子线程返回 `dJ?j[P,p  
try{ 4WXr~?Vq9  
if(bFirst) (q}{;  
{ 3DOc,}nI~@  
nFileLength = getFileSize(); PM^Xh*~  
if(nFileLength == -1) PX >>h}%  
{ .1F41UyL  
System.err.println("File Length is not known!"); ~u-_DOA  
} 4Ul*`/d  
else if(nFileLength == -2) 1k!$#1d<  
{ YJB/*SV^  
System.err.println("File is not access!"); CF]#0*MI  
} Z)!#+m83>-  
else xp%LXx j  
{ C:ntr=3J  
for(int i=0;i<nStartPos.length;i++) Yv"-_  
{ 6F; |x  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9t+:L(*pK  
} gr\vC  
for(int i=0;i<nEndPos.length-1;i++) O2S{*D={  
{ 91|~KR)  
nEndPos = nStartPos[i+1]; C] M{  
} sWFw[ Y>  
nEndPos[nEndPos.length-1] = nFileLength; qJK-HF:#  
} 17[vq!x6  
} 4%*`' o$_  
, %A2wV  
+?^lnoX  
//启动子线程 ;"]?&ri  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <4Ik]Uz^  
for(int i=0;i<nStartPos.length;i++) _Kg"l5?B  
{ fKNDl\SD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /vAA]n8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), uO4R5F|tL  
nStartPos,nEndPos,i); xbs X-F  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NT<}-^  
fileSplitterFetch.start(); Oee>d<  
} iCdq-r/r!6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `! _mIh}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Y|L]#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", [-h=L Jf#  
nEndPos = " + nFileLength); # N'_~:H  
// fileSplitterFetch[nPos.length-1].start(); 3$P GLM  
seA=7c5E  
"tz`@3,5dN  
//等待子线程结束 YQaL)t$0  
//int count = 0; c:,K{ZR  
//是否结束while循环 ,S-zY\XB  
boolean breakWhile = false; NLZUAtx(  
#.|MV}6rQ  
~i=5NUE  
while(!bStop) j,v2(e5:  
{ 0b+End#mp  
write_nPos(); -XWlmw*i(g  
Utility.sleep(500); XT\Q"=FD  
breakWhile = true; M~-jPY,+  
0]2@T=*kTY  
5 0<  
for(int i=0;i<nStartPos.length;i++) uEdeA'*^  
{ ::!{f+Up  
if(!fileSplitterFetch.bDownOver) @^^,VgW[  
{ 'Ug-64f>  
breakWhile = false; X;3gKiD  
break; D]hwG0Chd  
} HKYJgx  
} dPyZzMes=  
if(breakWhile) YHI@Cj  
break; 8&++S> <  
Cm[^+.=I  
crRYgr  
//count++; j/w*2+&v  
//if(count>4) jfsbvak  
// siteStop(); xkmqf7w  
} )r6d3-p1  
H(ds  
Y1L7sH 9  
System.err.println("文件下载结束!"); THz=_L6  
} K5:>  
catch(Exception e){e.printStackTrace ();} 8aa`0X/6  
} /Pgc W  
k{.`=j  
"oo j;  
//获得文件长度 Ap9 %5:]  
public long getFileSize() lwp(Pq  
{ xQ@gh ( (  
int nFileLength = -1; E~eSHJ(oR7  
try{ d/&~IR  
URL url = new URL(siteInfoBean.getSSiteURL()); jt4c*0z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V"Y-|R  
httpConnection.setRequestProperty("User-Agent","NetFox"); /|aD,JVN"  
46M?Gfd,X  
KPB^>,T2{  
int responseCode=httpConnection.getResponseCode(); E~'QC  
if(responseCode>=400) {igVuZ(>en  
{ 9xIz[`)i.  
processErrorCode(responseCode); l]KxUkA+  
return -2; //-2 represent access is error (}&O)3)  
} 6@cT;=W;xj  
O`Ge|4  
0ZjinWkR[  
String sHeader; _Sn7z?  
%TA@-tK=  
^V;2v? O  
for(int i=1;;i++) 5_= HtM[v]  
{ 3ew`e"s  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9ld'SB:#  
//Utility.log(in.readLine()); &kNJ s{  
sHeader=httpConnection.getHeaderFieldKey(i); "[p-Iy1  
if(sHeader!=null) w} 1~  
{ 8@- UvT&o  
if(sHeader.equals("Content-Length")) = , ^eQZR:  
{ CiTjRJ-ZW)  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 2'5%EQW;0y  
break; t&L+]I'P3  
} :;u?TFCRx  
} D+xHTQNTL  
else C6cEt5  
break; 6;vfl*  
} |*-&x:p7O  
} C lekB  
catch(IOException e){e.printStackTrace ();} Fi_JF;  
catch(Exception e){e.printStackTrace ();} euc|G Xs  
95^A !  
N)N\iad^  
Utility.log(nFileLength); Aq:1  
MW$ X4<*KD  
^E349c-|  
return nFileLength; f hS4Gb_  
} 1Xj>kE:  
R@Kzdeo  
vS_Ji<W~E  
//保存下载信息(文件指针位置) ae`6hW2  
private void write_nPos() \OX;ZVb?5  
{ -VVJf5/  
try{ )S 2GPn7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .PJCBT e  
output.writeInt(nStartPos.length); 9et%Hn.K'  
for(int i=0;i<nStartPos.length;i++) z),@YJU"z  
{ !HPye@Ua  
// output.writeLong(nPos); ]E!b&  
output.writeLong(fileSplitterFetch.nStartPos); >;}q  
output.writeLong(fileSplitterFetch.nEndPos); !<2%N3l  
} L?slIGp%-  
output.close(); ROc)LCA  
} MmPLJ  
catch(IOException e){e.printStackTrace ();} 27q=~R}  
catch(Exception e){e.printStackTrace ();} ueD_<KjE=  
} 5h6c W  
u~y0H  
o@!Uds0  
//读取保存的下载信息(文件指针位置) O ELh6R  
private void read_nPos() \Q m1+tg  
{ E+$%88  
try{ ltH?Ew<]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "g=g' W#  
int nCount = input.readInt(); o,yP9~8\  
nStartPos = new long[nCount]; ZN `D!e6  
nEndPos = new long[nCount]; pX~X{JTaL)  
for(int i=0;i<nStartPos.length;i++) 6mAaFDI,R  
{ 8M&q  
nStartPos = input.readLong(); v62M8r,Y  
nEndPos = input.readLong(); { *&Wc Os  
} eNEMyv5{w4  
input.close(); !:<(p  
} U.,_zEbx,  
catch(IOException e){e.printStackTrace ();} ta'{S=^j  
catch(Exception e){e.printStackTrace ();} -mur` tC  
} ?wpS  
:,'yHVG\  
4ZAnq{nR4  
private void processErrorCode(int nErrorCode) >q !:*  
{ .Fe_Z)i>h  
System.err.println("Error Code : " + nErrorCode); #D2.RN  
} $pLJtQ  
4u.Fy<+@4M  
9\J.AAk~/  
//停止文件下载 6*u WRjt  
public void siteStop() aR0'$*3E  
{ lc qpwSk  
bStop = true; )GC9%mF;  
for(int i=0;i<nStartPos.length;i++) Uxl7O4J@H  
fileSplitterFetch.splitterStop(); {`>;I  
zlhHSyK  
W8><  
} nA)KRCi  
} XJI ff$K  
//负责部分文件的抓取 Fk*C8  
**FileSplitterFetch.java u4QBD5T"  
*/ (l ]_0-Z  
package NetFox; 6Ex 16  
76BA1x+G  
Mr6q7  
import java.io.*; (S)jV 0  
import java.net.*; ]qPrXuS/  
oT}-i [=}  
MLk%U 4  
public class FileSplitterFetch extends Thread { T}r}uw`  
["7]EW\!:  
nSR<(-j!  
String sURL; //File URL @||GMA+|  
long nStartPos; //File Snippet Start Position r0L' mf$  
long nEndPos; //File Snippet End Position L+N;mI8  
int nThreadID; //Thread's ID e]k\dj;,^%  
boolean bDownOver = false; //Downing is over 3@8Zy:[8<  
boolean bStop = false; //Stop identical YU6D;  
FileAccessI fileAccessI = null; //File Access interface X6G2$|  
'v0(ki#  
R>y/Y<5=  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ihBIE  
{ %shCqS  
this.sURL = sURL; v!6IH  
this.nStartPos = nStart; ?AYb@&%  
this.nEndPos = nEnd; &\L\n}i-  
nThreadID = id; ~fY\;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6)[gF 1  
} {vox x&UX  
YlJ_$Q[  
++Fv )KY@  
public void run() DW >|'w%  
{ !~ fy".|x  
while(nStartPos < nEndPos && !bStop) JL!:`#\  
{ PsO>&Te2  
f(E[jwy  
EWK?vs  
try{ v%E~sX&CG  
URL url = new URL(sURL); V(P 1{g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P]<15l  
httpConnection.setRequestProperty("User-Agent","NetFox"); X1 FKcWv  
String sProperty = "bytes="+nStartPos+"-"; z6uHe{|  
httpConnection.setRequestProperty("RANGE",sProperty); *yqke<o9)  
Utility.log(sProperty); NEW0dF&)  
-fT}Nj\  
w" ,ab j  
InputStream input = httpConnection.getInputStream(); 1HBWOV7z.?  
//logResponseHead(httpConnection); DSL3+%KF#  
SdNxSD$Q  
~'VVCtA  
byte[] b = new byte[1024]; {ug*  
int nRead; 8c5=Px2\  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) wj 15Og?  
{ j5MUP&/g3  
nStartPos += fileAccessI.write(b,0,nRead); Ls/*&u  
//if(nThreadID == 1) ",P?jgs^g5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); GxS!Lk  
} K8{ef  
DA^!aJ6iF  
#4!6pMW(&7  
Utility.log("Thread " + nThreadID + " is over!"); IO?6F@(  
bDownOver = true; 5fK<DkB$>:  
//nPos = fileAccessI.write (b,0,nRead); zuvP\Y=V`  
} PSa"u5O  
catch(Exception e){e.printStackTrace ();} %$F\o1S  
} sUsIu,1Q  
} V _pKe~  
Zy > W2(<  
a4N8zDS  
//打印回应的头信息 =eG:Scoug?  
public void logResponseHead(HttpURLConnection con) el,n5O Z7  
{ eXMl3Lxf  
for(int i=1;;i++) C-ipxL"r  
{ HO;,Ya^l  
String header=con.getHeaderFieldKey(i); #NWc<Dd  
if(header!=null) K|-RAjE  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 6Q9S~YYq  
Utility.log(header+" : "+con.getHeaderField(header)); tNCKL. yU  
else O)G^VD s  
break; U`ELd:  
} n\H.NL)  
} sTO9>~sj  
5[$jrG\!  
cGe-|>:  
public void splitterStop() >"+bL6#  
{ pc<A ,?  
bStop = true; 6w^Fee`>]  
} h-[FUPfuw  
N^K@$bs4^  
}K\m.+%=d  
} W=T,hOyh<W  
&sJ%ur+G  
5R7DD5c[  
/* *Ldno`1O  
**FileAccess.java 4 g^oy^~  
*//文件访问(定位,写) G=%SMl>[  
package NetFox; &c1zEgl  
import java.io.*; | WMq&-$D  
QAh6!<.;@  
h ?%]uFJC  
public class FileAccessI implements Serializable{ lVQy {`Ns  
RP4P"m(   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 seo.1.Da2  
RandomAccessFile oSavedFile; 2DTBL:?`  
long nPos; \@HsMV2+zN  
7cJh^M   
LdM9k(  
public FileAccessI() throws IOException s0x;<si_  
{ !*l5%H  
this("",0); Qcf5* ]V  
} W{v-(pW  
)mw&e}jRV  
41V}6+$g  
public FileAccessI(String sName,long nPos) throws IOException  G(1y_t  
{ D27MT/=7  
oSavedFile = new RandomAccessFile(sName,"rw"); 'u{DFMB-A  
this.nPos = nPos; _Y gvLz %  
oSavedFile.seek(nPos); 2E":6:Wsw  
} =^LX,!2zp{  
tX#8 G09G+  
<..|:0Q&~  
public synchronized int write(byte[] b,int nStart,int nLen) lP:ll])p2  
{ .;xt{kK  
int n = -1; g$jZpU  
try{ D~s TQfWr  
oSavedFile.write(b,nStart,nLen); q|+`ihut  
n = nLen; (\M&Q-xZ  
} D,H v(6({  
catch(IOException e) .\X;VWTI  
{ fudIUG.  
e.printStackTrace (); l6lyRJ  
} a5AD$bP  
.oNs8._:  
M[@=m[#a  
return n; "me a*-XB  
} 3 O)^Hq+9  
+w]KK6  
![,W?  
} U- a+LS  
@m=xCg.Z  
`bdCom  
/* >;A7mi/  
**SiteInfoBean.java 0Lo)Ni^"  
*/ C& QT-|  
package NetFox; 18AKM  
Oa'DVfw2J  
kq SpZoV0'  
public class SiteInfoBean { FesXY856E  
x]Nk T  
J AK+v  
private String sSiteURL; //Site's URL 5Cp6$V|/kv  
private String sFilePath; //Saved File's Path ,y+}0q-Ou  
private String sFileName; //Saved File's Name POtj6 ?a  
private int nSplitter; //Count of Splited Downloading File vncak  
:|\{mo1NB  
 6tPgFa#N  
public SiteInfoBean() E26zw9d  
{//nSplitter的缺省值为5 avb'J^}f  
//default value of nSplitter is 5 5VU 5kiCt  
this("","","",5); OUd&fUmH  
} bk-veJR  
)e$}sw{t  
@nuMl5C-`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]}wo$7pO  
{ `n*e8T  
sSiteURL= sURL; f8T6(cA  
sFilePath = sPath; H+oQ L(i|_  
sFileName = sName; vbo:,]T<A  
this.nSplitter = nSpiltter; {!lC$SlJ  
_NfdJ=[Xh  
k_E Jg;(  
} GI~JIXHTQ  
4pin\ZS:C  
Rd?8LLz  
public String getSSiteURL() g69^D  
{ -A?6)ggf.  
return sSiteURL; d-zNvbU"  
} Z#O )0ou  
1%v!8$  
>tmv3_<=  
public void setSSiteURL(String value) Ej\M e  
{ AG3iKk??T  
sSiteURL = value; w)# Lu/  
} 78=a^gRB  
_ (U|Kpi  
!CBvFl/v  
public String getSFilePath() U?bQBHIC  
{ Ix-bJE6+I,  
return sFilePath; 7s2 l3  
} t",=]k  
FZt a  
Jv,*rQH  
public void setSFilePath(String value) > a"4aYj  
{ 6,j&u7  
sFilePath = value; oV,lEXz  
} 6e q`/~#  
k`;&??  
-$@4e|e%a  
public String getSFileName() ;{S7bH'6m  
{ S/H!a:_5r  
return sFileName; {q^?Rw  
} n}!D)Gx  
@$] CC1Y  
O$$$1VHYo  
public void setSFileName(String value) 8iKupaaOX  
{ ganXO5T$  
sFileName = value; ~ s# !\Ye  
} 6S6E 1~  
01AzM)U3"m  
w?Nx ^)xX  
public int getNSplitter() xjO((JC  
{ y+K21(z.  
return nSplitter; +t`QHvxv  
} eHQ3K#M#  
,.PW qfb  
}5{#f`Ca6  
public void setNSplitter(int nCount) "F8A:tR  
{ J2P5<  
nSplitter = nCount; 1h0cId8d  
} u>I;Cir4  
} m(c5g[6nO  
B}A7Usm  
wD'LX  
/* "J(7fL$!  
**Utility.java 1> wt  
*/ 4RU/y+[o  
package NetFox; H;nq4;^yK  
qGgqAF#B  
ecgGl,{  
public class Utility { 2gC.Z:}  
=|G l  
h=Xr J  
public Utility() <D!\"C  
{ 3kl\W[`?  
d,0Yi u.p  
g,seqh%  
} =W Q_5}  
kb>/R/,9  
//线程睡眠 h0)Wy>B=,  
public static void sleep(int nSecond) _'lrI23I  
{ _a3,Zuv  
try{ _Xn[G>1  
Thread.sleep(nSecond); nS}XY  
} c>*RQ4vE  
catch(Exception e) i C nWb  
{ t6)wR  
e.printStackTrace (); ZxRD+`  
} [|\JIr=of5  
} Jm+hDZrW  
}FTyRHD|  
//日志 2@ <x%T  
public static void log(String sMsg) ~X/1%  
{ !PzlrH)M=p  
System.err.println(sMsg); fi2@`37PM  
} Rj|8l K;,  
jI8qiZ);~  
1o;+.]B  
public static void log(int sMsg) :(|;J<R%_  
{ ,\|W,N}~  
System.err.println(sMsg); [kyF|3k~  
} /Wh} ;YTv^  
} ueiXY|  
XZv(B^  
\wxS~T<&L  
/* wPn#>\/L  
**TestMethod.java 0wLu*K5$4E  
*/ n0T\dc~  
package NetFox; (o1*7_]e  
D-/K'|b  
4*4s{twG  
public class TestMethod { ?Mg&e/^  
[lqwzW{(UN  
wjF/c  
public TestMethod() $#g1Mx{  
{ ///xx/weblogic60b2_win.exe S=>54!{`x  
try{ x?:[:Hf   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /#z5bo  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ISI\< qx  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "r!O9X6  
fileFetch.start(); 0Ii* "?s  
} Ji_3*(  
catch(Exception e){e.printStackTrace ();} 92F (Sl  
7u!i)<pn  
Wc4F'}s  
} r^mP'#  
0*MY4r|-  
kzqW&`xn?  
public static void main(String[] args) :?s~,G_*l  
{ G};os+FxF  
new TestMethod(); JzJS?ZF  
} >(s)S[\  
} nc#}-}`5  
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