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http断点续传简单实现(java)

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/* #G|RnV%t$~  
**SiteFileFetch.java f*% D$Mqg  
*/ SM#]H-3  
package NetFox; t|\%VC  
import java.io.*; I*{ nP)^9  
import java.net.*; d L 1tl  
4[r0G+  
uBKgcpvTs  
public class SiteFileFetch extends Thread { ~H_/zK6e  
nNV'O(x}  
dq6m>;`  
SiteInfoBean siteInfoBean = null; //文件信息Bean _/$Bpr{R  
long[] nStartPos; //开始位置 7>0o&  
long[] nEndPos; //结束位置 x /S}Q8!"}  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 xh,qNnGGi  
long nFileLength; //文件长度 \ a<h/4#|  
boolean bFirst = true; //是否第一次取文件 k,6f &#x  
boolean bStop = false; //停止标志 /4V#C-  
File tmpFile; //文件下载的临时信息 t#})Awy^R  
DataOutputStream output; //输出到文件的输出流 J?1 uKR  
::lKL  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) wu!59pL  
public SiteFileFetch(SiteInfoBean bean) throws IOException r'r%w#=`t  
{ zkrM/ @p#  
siteInfoBean = bean; 4r#= *  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 85$m[+md  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); dr}`H,X"3  
if(tmpFile.exists ()) x,+{9  
{ |bHelD|  
bFirst = false; -UEZ#Q  
read_nPos(); TDKki(o=~  
} BLdvyVFx  
else ]i)c{y  
{ }O5i/#.lR  
nStartPos = new long[bean.getNSplitter()]; PI)+Jr%L  
nEndPos = new long[bean.getNSplitter()]; (O?.)jEW(.  
} d#Y^>"|$.  
rSk >  
29"'K.r  
W~; `WR;.  
} Lc,Pom  
~9]hV7y5C  
Qh3YJ=X&  
public void run() |Nn)m  
{ RDi]2  
//获得文件长度 o Q2Fjj  
//分割文件 `Bp.RXsd*  
//实例FileSplitterFetch *uf'zQ<9  
//启动FileSplitterFetch线程 8 &LQzwa  
//等待子线程返回 +b<FO+E_  
try{ $E~`\o%Ev  
if(bFirst) A*2jENgci  
{ 7M!I8C0!aO  
nFileLength = getFileSize(); HxV=F66"  
if(nFileLength == -1) HY*Kb+[  
{ Y@vTaE^w3  
System.err.println("File Length is not known!"); QzVnL U)  
}  a=9:[  
else if(nFileLength == -2) W?R6ZAn  
{ 4<Utmr  
System.err.println("File is not access!"); w^|*m/h|@u  
} VcO0sa f`  
else Gbr=+AT  
{ GL#up  
for(int i=0;i<nStartPos.length;i++) 8@Q$'TT6}  
{ mbxZL<ua  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); C.yQ=\U2  
} HGs $*  
for(int i=0;i<nEndPos.length-1;i++) b\kdKVh&  
{ D6Ui!  
nEndPos = nStartPos[i+1]; f!uwzHA`?  
} TH&U j1  
nEndPos[nEndPos.length-1] = nFileLength; s}9S8@#  
} Y-_`23x`  
} R6Km\N  
m@2QnA[ 4  
KNvZm;Q6  
//启动子线程 RuA*YV  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; y<|7z99L  
for(int i=0;i<nStartPos.length;i++) O7m(o:t x3  
{ mb TEp*H  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i {NzV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), }<v@01  
nStartPos,nEndPos,i); 5y [Oj^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); iDp)FQ$  
fileSplitterFetch.start(); D9=KXo^  
} JN-y)L/>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (AaoCa[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); RQ'9m^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]Kt6^|S$a  
nEndPos = " + nFileLength); C=L>zOZ  
// fileSplitterFetch[nPos.length-1].start(); v\gLWq'  
5oW!YJg  
g0=z&2Q[_)  
//等待子线程结束 P|tO<t6/9*  
//int count = 0; *xxx:*6rk;  
//是否结束while循环 KE5kOU;  
boolean breakWhile = false; q]ku5A\y  
qpP=K $  
ooj,/IEQ  
while(!bStop) 3tIVXtUCUk  
{ @]%IK(|  
write_nPos(); _LEK%  
Utility.sleep(500); mZS >O_E  
breakWhile = true; kX7C3qdmt  
WYm\)@  
nLZTK&7}  
for(int i=0;i<nStartPos.length;i++) pk$l+sNZ=  
{ SumF  2  
if(!fileSplitterFetch.bDownOver) OUPUixz2Z  
{ ~S"+S/z/k  
breakWhile = false; ifMRryN4  
break; 2 /\r)$ 2i  
} 7Jyy z,!5  
} en4k/w_  
if(breakWhile) =vCY?I$P  
break; zII|9y  
)hn6sXo+  
u^ +7hkk  
//count++; DZ'P@f)]  
//if(count>4) {0Yf]FQb-a  
// siteStop(); ,Bi.1 %$  
} dC3o9  
Z*]9E^  
vAF "n  
System.err.println("文件下载结束!"); <sGVR5NR  
} Db}j?ik/  
catch(Exception e){e.printStackTrace ();} ;40/yl3r3[  
} Fx_z6a  
r"3=44St  
|PCm01NU!  
//获得文件长度 )np:lL$$  
public long getFileSize() :1. L}4"gg  
{ shy-Gu&  
int nFileLength = -1; v!-/&}W)1  
try{ {yTGAf-DV  
URL url = new URL(siteInfoBean.getSSiteURL()); [[Ls_ZL!=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F3[T.sf  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^+>laOzC`8  
.GP T!lDc  
2+ N]PW\V  
int responseCode=httpConnection.getResponseCode(); j ?3wvw6T  
if(responseCode>=400) T"}5}6rSG  
{ X Swl Tg  
processErrorCode(responseCode); ?|\ER#z  
return -2; //-2 represent access is error [\98$BN  
} E!)xj.aS$  
(&Kk7<#`  
5FPM`hLT  
String sHeader; &v/dj@   
MO]F1E?X  
6RU~"C  
for(int i=1;;i++) #>("CAB02T  
{ ~|D Ut   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); UawyDs  
//Utility.log(in.readLine()); :gv{F} ##  
sHeader=httpConnection.getHeaderFieldKey(i); lV3x*4O=  
if(sHeader!=null) Fh&G;aEq  
{ Wa>}wA=v  
if(sHeader.equals("Content-Length")) lwxaMjaL4K  
{ d`=MgHz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); FJ GlP&v<  
break; `!3SF|x&  
} Zgp4`)}:  
} Tt`u:ZwhF  
else 6m/r+?'  
break; U/66L+1  
} xf\C|@i  
} J\} twYty  
catch(IOException e){e.printStackTrace ();} Fo (fWvz  
catch(Exception e){e.printStackTrace ();} hlvK5Z   
Jc&{`s^Nu  
Fj8z  
Utility.log(nFileLength); xA2YG|RU=b  
EqkN3%IG  
c)6m$5]  
return nFileLength; fZGX}T<)p-  
} .ljnDL/  
pGP7nw_g  
jh?H.;**  
//保存下载信息(文件指针位置) Y #ap*  
private void write_nPos() _P#|IAq*  
{ bI7Vwyz  
try{ z}77Eh<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .FP$m?  
output.writeInt(nStartPos.length); q<x/Hat)  
for(int i=0;i<nStartPos.length;i++) R^8o^z['6u  
{ + B,}Qr  
// output.writeLong(nPos); G=s}12/Z"{  
output.writeLong(fileSplitterFetch.nStartPos); Pf")e,u$  
output.writeLong(fileSplitterFetch.nEndPos); <6%?OJhp  
} 58}U^IW  
output.close(); GLH0 ]  
} U#7#aeI  
catch(IOException e){e.printStackTrace ();} p}}R-D&K  
catch(Exception e){e.printStackTrace ();} x xHY+(m  
} '|6]_   
<VMGTBVQ  
_b pP50Cu  
//读取保存的下载信息(文件指针位置) XAD- 'i  
private void read_nPos() wyH[x!QX  
{ W]$w@.oW[  
try{ H `XUJh  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 7y'RFD9@{  
int nCount = input.readInt(); NR$3%0 nC6  
nStartPos = new long[nCount]; W 8<&gh+  
nEndPos = new long[nCount]; kP=eW_0D  
for(int i=0;i<nStartPos.length;i++) d~])K#oJ  
{ X~b X5b[P  
nStartPos = input.readLong(); 6%\J"AgXO  
nEndPos = input.readLong(); \Gef \   
} Y,qI@n<  
input.close(); hk;5w{t}}  
} v4a8}G  
catch(IOException e){e.printStackTrace ();} +qN>.y!Y  
catch(Exception e){e.printStackTrace ();} r5S[-`s;  
} '0;l]/i.  
^ox=HNV  
@Z_x.Y6  
private void processErrorCode(int nErrorCode) 0Uz"^xO["  
{ >.Pnkx*  
System.err.println("Error Code : " + nErrorCode); L8@f-Kk  
} c`)\Pb/O  
etQCzYIhn  
udK%>  
//停止文件下载 w0 M>[ 4  
public void siteStop() EgEa1l!NSQ  
{ dM.f]-g  
bStop = true; pHGYQ;:L  
for(int i=0;i<nStartPos.length;i++) B B{$&Oh  
fileSplitterFetch.splitterStop(); ]6,\r"  
O0x,lq  
SBu"3ym  
} 4!{KWL`A  
} Ot0ap$&  
//负责部分文件的抓取 TIqtF&@o4  
**FileSplitterFetch.java ^cC,.Fdw  
*/ ^ 'MT0j  
package NetFox; c1(RuP:S  
.|KyNBn  
soB,j3#p'*  
import java.io.*; >a<.mU|#  
import java.net.*; PudS2k_Qv  
JJ-( Sl  
UkwP  
public class FileSplitterFetch extends Thread { d UE,U=  
sPpH*,(  
-a}Dp~j  
String sURL; //File URL 5+0gR &|j  
long nStartPos; //File Snippet Start Position 2 0h} [Q(  
long nEndPos; //File Snippet End Position h%na>G  
int nThreadID; //Thread's ID x3=A:}t8  
boolean bDownOver = false; //Downing is over <18(  
boolean bStop = false; //Stop identical #b}Z`u?@  
FileAccessI fileAccessI = null; //File Access interface _IHV7*u{;  
:1Xz4wkWS*  
aH(J,XY  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ,Q$ q=E;X  
{ GTPHVp&y  
this.sURL = sURL; :wyno#8`-  
this.nStartPos = nStart; Vi$~-6n&  
this.nEndPos = nEnd; "m$##X\  
nThreadID = id; IZ-1c1   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 J9nX"Sb  
} PCee<W_%YE  
/ y40(l?  
8mrUotjS  
public void run() Pl06:g2I  
{ 6dr%;Wp  
while(nStartPos < nEndPos && !bStop) bjW]bRw  
{ pZ{+c  
|-67 \p]  
<]t%8GB2V  
try{ :as$4|  
URL url = new URL(sURL); yx8z4*]kH  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wo{gG?B  
httpConnection.setRequestProperty("User-Agent","NetFox"); qbN =4  
String sProperty = "bytes="+nStartPos+"-"; A1$TXr  
httpConnection.setRequestProperty("RANGE",sProperty); ] )\Pqn(  
Utility.log(sProperty); Igt#V;kK"2  
LKB$,pR~1l  
c9 eM/*:  
InputStream input = httpConnection.getInputStream(); Oc0a77@  
//logResponseHead(httpConnection); U[-o> W#  
9MJG;+B~  
H [\o RId  
byte[] b = new byte[1024]; oG?Xk%7&\  
int nRead; 3BUSv#w{i  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y;M|D'y+  
{ !;v|'I  
nStartPos += fileAccessI.write(b,0,nRead); <8&au(I,vB  
//if(nThreadID == 1) h 0Q5-EA  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `:KY\  
} M#6W(|V/  
ifQ*,+@fxR  
Wq&if_  
Utility.log("Thread " + nThreadID + " is over!"); ;?i W%:_,  
bDownOver = true; %3-y[f  
//nPos = fileAccessI.write (b,0,nRead); Np9<:GF1  
} CAWNDl4  
catch(Exception e){e.printStackTrace ();} BoWg0*5xb  
} dt]-,Y  
} 1N-\j0au  
Y\k#*\'Y~  
z'n:@E  
//打印回应的头信息 b94DJzL1z  
public void logResponseHead(HttpURLConnection con) {$ JYw{a  
{ *u[BP@vE  
for(int i=1;;i++) &)ChQZA  
{ U(g:zae  
String header=con.getHeaderFieldKey(i); Cctu|^V  
if(header!=null) D_*WYV  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); - %h.t+=U  
Utility.log(header+" : "+con.getHeaderField(header)); :U%W%  
else nh>vixe  
break; Y eo]]i{  
} .@U@xRu7|  
} ^"2J]&x`G  
\V8PhO;j  
xJ8M6O8  
public void splitterStop() *vxk@ `K~  
{ mxC;?s;~  
bStop = true; b5vC'B-!  
} 1~ 3_^3OT  
*)T^Ch D,  
#OD/$f_  
} ,m:.-iy?  
(Zrj_P`0[  
0&|\N ? 8_  
/* E,U+o $  
**FileAccess.java kJsN|=  
*//文件访问(定位,写) & G4\2l9  
package NetFox; xF'EiX~  
import java.io.*; E A1?)|}n  
WiR(;m<g  
]Ie 0S~  
public class FileAccessI implements Serializable{ J @1!Oq>  
}rw8PZ9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 E KLyma&}Y  
RandomAccessFile oSavedFile; ]MitOkX  
long nPos; kfY}S  
3$>1FoSk  
VU]`&`~J  
public FileAccessI() throws IOException |N7M^  
{ N +_t-5  
this("",0); xy[3u?,&s!  
} | rtD.,m   
oIzj,v8$  
y I  
public FileAccessI(String sName,long nPos) throws IOException ,f'CD{E  
{ 9F;>W ET  
oSavedFile = new RandomAccessFile(sName,"rw"); 6}Ci>_i4#  
this.nPos = nPos; 37.S\ gO]  
oSavedFile.seek(nPos); K;H&n1  
} YfKdR"i+.  
8^+%I/S$  
qWPkT$ u  
public synchronized int write(byte[] b,int nStart,int nLen) rcG"o\g@+  
{ 'yEHI  
int n = -1; c]o'xd,T8\  
try{ {]@= ijjf  
oSavedFile.write(b,nStart,nLen); YZ8>OwQz2  
n = nLen; [<yaXQxl  
} P{>!5|k  
catch(IOException e) >jLY"  
{ O-hAFKx  
e.printStackTrace (); L\"d  
}  |TH\`U  
 DA,?}  
%pL''R9VF  
return n; 0znR0%~  
} _8UU'1d  
'S&zCTX7j  
0pd'93C  
} 16(QR-  
p6Gy ,C.  
[]1C$.5DD  
/* *P=VFP  
**SiteInfoBean.java E4/Dr}4  
*/  >Abdd  
package NetFox; 0=1T.4+=  
N5 6g+,w%)  
}(73Syl#  
public class SiteInfoBean { 3;A)W18]  
SO'vp z{  
N<VJ(20y  
private String sSiteURL; //Site's URL y??XIsF  
private String sFilePath; //Saved File's Path x g  
private String sFileName; //Saved File's Name vXZOy%$o  
private int nSplitter; //Count of Splited Downloading File '_FsvHQ  
f46t9dxp$  
PKiy5D*8p  
public SiteInfoBean() >KhOz[Zg  
{//nSplitter的缺省值为5 :':s@gqr  
//default value of nSplitter is 5 9qzHS~l  
this("","","",5); 0 /U{p,r6`  
} Kis"L(C  
yWo; a  
i<Zc"v;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) VjZ|$k  
{ `b7t4d*  
sSiteURL= sURL; Iit; F  
sFilePath = sPath; Eo]xNn/g  
sFileName = sName; 2pa5U;u:+  
this.nSplitter = nSpiltter; 4>e&f&y~  
c<Tf 2]vZE  
7ZWgf"1j  
} y766; X:J  
=GMkR+<)  
8'io$ 6d=  
public String getSSiteURL() h MD|#A-<  
{ SoSb+\* @h  
return sSiteURL; KB(8f*  
} M%P:n/j  
)1`0PJoHE  
j'"J%e]  
public void setSSiteURL(String value) $B5aje}i  
{ r52gn(,  
sSiteURL = value; 6mxfLlZ  
} -X2Buz8  
9EibIOD^/  
I:1C8*/  
public String getSFilePath() U8n V[  
{ M-Y_ Wb3  
return sFilePath; !wh8'X*  
} =MDys b&:  
],Do6 @M-  
P{ lB50  
public void setSFilePath(String value) sWnLEw  
{ ;+ hH  
sFilePath = value; v;D~Pa  
} Y O}<Ytx  
=$JET<(  
s R/F"  
public String getSFileName() ')<hON44EX  
{ _ *Pf  
return sFileName; +Q"4Migbe@  
} r0% D58  
*#+An<iT ;  
z[qDkL  
public void setSFileName(String value) 3 {sVVq5Y  
{ $Ri; ^pZw[  
sFileName = value; _ZSR.w}j/  
} wgGl[_)  
Y\g3h M  
pG;U2wE  
public int getNSplitter() \bvfEP  
{ &E5g3lf  
return nSplitter; 'c$+sp ?  
} %YqEzlzF  
p947w,1![  
N6i Q8P -  
public void setNSplitter(int nCount) R%[ c;i  
{ dhK~O.~m  
nSplitter = nCount; P.9>z7l{  
} lA8`l>I  
} ]Gq !`O1  
:P0mx   
-r]W  
/* _L=h0H l  
**Utility.java oE]QF.n#  
*/ -]M5wb2,  
package NetFox; G2: agqL/  
4ID5q~  
_u QOHwn  
public class Utility { <=C!VVk4f  
<x>M o   
or}[h09qA  
public Utility() rf{rpe$  
{ v0.#Sl-  
)bscBj@  
3AN/ H  
} XUuN )i  
|Ds1  
//线程睡眠 -m~#Bq  
public static void sleep(int nSecond) PALc;"]O  
{ oe-\ozJ0  
try{ aO4?m+  
Thread.sleep(nSecond); {;6`_-As%  
} &6nWzF  
catch(Exception e) ~oY^;/ j  
{ \z(gqkc 6  
e.printStackTrace (); ?^\|-Gr  
} sD#.Oq4&]y  
} .U]-j\  
40m-ch6Q  
//日志 ^Xh^xL2cn  
public static void log(String sMsg) -PR N:'T  
{ v mk2{f,g  
System.err.println(sMsg); '?(% Zxw%&  
} w ;^ra<*<+  
</*6wpN  
>tW#/\x{  
public static void log(int sMsg) sLxc(d'A  
{ o|["SYIf  
System.err.println(sMsg); gc$l^`+M  
} O3kA;[f;  
} JDT`C2-Q  
X45%e!  
`3&v6  
/* r mg}N  
**TestMethod.java 7J<5f)  
*/ QhJiB%M  
package NetFox; 8 v%o,"  
&^Q/,H~S  
c\AfaK^KF  
public class TestMethod { ;u)I\3`*!  
1bX<$>x9u  
SO0PF|{\r  
public TestMethod() [`7ThHX  
{ ///xx/weblogic60b2_win.exe 20Wg=p9L  
try{ c yz3,3\e  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); r* Ca}Z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +QJ#2~pE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); eehb1L2(b  
fileFetch.start(); 5$C-9  
} 11;MN  
catch(Exception e){e.printStackTrace ();} B tcy)LRk  
A~70  
$qj2w"'  
} I b5rqU\  
E~"y$Fqe  
o?\?@H  
public static void main(String[] args) ZPYS$Ydy  
{ tY4;F\e2|A  
new TestMethod(); ~Z' ?LV<t  
} fI|Nc  
} d7bS wL  
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