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http断点续传简单实现(java)

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/* .xH5fMj,"  
**SiteFileFetch.java ZRg;/sX]  
*/ SVB\  
package NetFox; ~,5gUl?Il  
import java.io.*; 5[YDZ7g"~  
import java.net.*; fM^qQM[lG  
=W BTm  
6u7?dG'4  
public class SiteFileFetch extends Thread { pm_u  
WqXbI4;pJ  
H=Y{rq@  
SiteInfoBean siteInfoBean = null; //文件信息Bean fv9V7  
long[] nStartPos; //开始位置 Te}8!_ohyC  
long[] nEndPos; //结束位置 79xx2  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 EodQ*{l  
long nFileLength; //文件长度 pXtXjb  
boolean bFirst = true; //是否第一次取文件 j{9D{  
boolean bStop = false; //停止标志 nAjO6g6E  
File tmpFile; //文件下载的临时信息 2|}+T6_q  
DataOutputStream output; //输出到文件的输出流 Q^e}?v%=%3  
5Drq9B9;  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 6T#+V37  
public SiteFileFetch(SiteInfoBean bean) throws IOException {yB&xj[z  
{ aM:nOt" S1  
siteInfoBean = bean; $l|qk  z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "vyNxZE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3T!lA  
if(tmpFile.exists ()) ZsOIH<}S  
{ @)4]b+8Z  
bFirst = false;  s8rE$  
read_nPos(); $}jssnoU  
} YtfVD7m  
else j&Wl0  
{ >w^YO25q  
nStartPos = new long[bean.getNSplitter()]; ~?FpU  
nEndPos = new long[bean.getNSplitter()]; Ju :CMkv  
} 6DuEL=C  
[3--(#R\}?  
:kf`?u  
`R=HKtr?  
} GP:77)b5  
R5 9S@MsuD  
UM6(s@$  
public void run() "G@g" gP  
{ mM-8+H?~b  
//获得文件长度 *Ie7{EhJ'  
//分割文件 $+3}po\  
//实例FileSplitterFetch 0Pe>Es|^A#  
//启动FileSplitterFetch线程 W>p-u6u%E|  
//等待子线程返回 o)2W`i&  
try{  )8UWhl=  
if(bFirst) thvYL.U :  
{ q11>f   
nFileLength = getFileSize(); tGl;@V@Qj  
if(nFileLength == -1) 3 "Q=Vl"  
{ x`dHJq`_g  
System.err.println("File Length is not known!"); FTQ%JTgT  
} %e(z /"M=`  
else if(nFileLength == -2) 6N;wqn  
{ 45MLt5^|  
System.err.println("File is not access!"); D?8rO"  
} ;F~LqC$  
else K/3)g9Z&io  
{ g;8jK 8 Kh  
for(int i=0;i<nStartPos.length;i++) }woo%N P  
{ mA*AeP_$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N 0= ac5  
} ?hWwj6i&  
for(int i=0;i<nEndPos.length-1;i++) S!3S4:]B^  
{ NZ-\h  
nEndPos = nStartPos[i+1]; c(n&A~*AJ%  
} isZAoYVu  
nEndPos[nEndPos.length-1] = nFileLength; 'toa@5  
} nx^]>w  
} B{C??g8/  
Xp8]qH|K   
vL\&6n~M>  
//启动子线程 <B6&I$Wc+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; d)R:9M}v  
for(int i=0;i<nStartPos.length;i++) KB'qRnkc  
{ sPMa]F(  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V8HnUuz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), N.]qU d  
nStartPos,nEndPos,i); :SGF45>B@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9lW;Nk*j:  
fileSplitterFetch.start(); Eg2[k.{P  
} MF'$~gxo  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t $xY #:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ghX|3lI\q  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", krC{ed  
nEndPos = " + nFileLength); (h5'9r  
// fileSplitterFetch[nPos.length-1].start(); 8rMX9qTO@  
Ar:*oiU  
!2'jrJGc  
//等待子线程结束 L?Qg#YSd ~  
//int count = 0; dUF&."pW e  
//是否结束while循环 7"w2$*4'0  
boolean breakWhile = false; -xDGH  
5KDGSo  
`}l JH i  
while(!bStop) bBS,-vN  
{ bLQ ^fH4ww  
write_nPos(); u#V5?i  
Utility.sleep(500); K!'AkTW+-  
breakWhile = true; _`_%Y(Xat  
w - Pk7I  
'eJ+JM<0%  
for(int i=0;i<nStartPos.length;i++) lI-L` x  
{ o_D?t-XH  
if(!fileSplitterFetch.bDownOver) Lv'D^'I  
{ 6C]1Q.f;  
breakWhile = false; S`"LV $8  
break; M\Z6$<H?U  
} I-WhH>9  
} &znQ;NH#  
if(breakWhile) m"fNK$_d  
break; kRTwaNDOD  
_%B^9Yl3(  
@H7Wb}  
//count++; >9q&PEc  
//if(count>4) |iR T! ]  
// siteStop(); (A?H1 9  
} |d*&y#kV  
ewfP G,S  
rfgI$eu   
System.err.println("文件下载结束!"); E7CH^]x  
} Wo7F  
catch(Exception e){e.printStackTrace ();} Tjl:|F8  
} OnF3lCmu  
pDh{Z g6t  
-|Y(V5]  
//获得文件长度 BVr0Gk  
public long getFileSize() v|Yh w  
{ Xy@7y[s]  
int nFileLength = -1; Pj4/xX  
try{ *+\S yO  
URL url = new URL(siteInfoBean.getSSiteURL()); h~p>re  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7G\\{  
httpConnection.setRequestProperty("User-Agent","NetFox"); H'LD}\K l  
j8fpj{hp  
;Ww7"-=sw  
int responseCode=httpConnection.getResponseCode(); FRS>KO=3  
if(responseCode>=400) {2+L @  
{ ;[W"mlM  
processErrorCode(responseCode); UQ+?\wi*  
return -2; //-2 represent access is error VH(S=G5Yb  
} F@*+{1R  
)QG<f{wS  
`X`2:@gQ  
String sHeader; E[*Fz1>  
aS pWsT  
#F*1V(!  
for(int i=1;;i++) )* Q-.Je/U  
{ KM !k$;my  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 6X\ 2GC9  
//Utility.log(in.readLine()); =Apxdnz,  
sHeader=httpConnection.getHeaderFieldKey(i); {qmdm`V[  
if(sHeader!=null) o.'g]Q<}UB  
{ TP"1\O  
if(sHeader.equals("Content-Length")) {O,{c\  
{ Uv?|G%cD-  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); KLL;e/Gf  
break; V h k _  
} Tzn tO9P+  
} 0%Z]h?EYy|  
else u&9 r2R959  
break; ]\xy\\b/`  
} ]_8qn'7  
} i@B[ eta  
catch(IOException e){e.printStackTrace ();} ~>:Z6Le@   
catch(Exception e){e.printStackTrace ();} h?f>X"*|(  
MUA%^)#u4Q  
wo3wtx  
Utility.log(nFileLength); ylB7*>[  
m@Qt.4m%g  
X5`AGyX  
return nFileLength; KMV=%o  
} ?qX)ihe%k  
:Pg}Zz<  
n f.wCtf].  
//保存下载信息(文件指针位置) 4<?8M vF  
private void write_nPos() ;i"*Ll>Q)  
{ Y)$ ;Ax-D  
try{ #."Hh<C  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3` #6ACF  
output.writeInt(nStartPos.length); m1IKVa7-\}  
for(int i=0;i<nStartPos.length;i++) 6sE{{,OGB  
{ !p[9{U->o;  
// output.writeLong(nPos); g(Io/hyj  
output.writeLong(fileSplitterFetch.nStartPos); #!$GH_  
output.writeLong(fileSplitterFetch.nEndPos); `c69 ?/5  
} sj8~?O  
output.close(); Ht-t1q  
} w~ ;I7:  
catch(IOException e){e.printStackTrace ();} eh,~F   
catch(Exception e){e.printStackTrace ();} i:cXwQG}B  
} Pf$pt  
r 3M1e+'fc  
DwV4o^J:l  
//读取保存的下载信息(文件指针位置) `zR+tbm  
private void read_nPos() Kv rX{F=  
{ $rhgzpZ!X_  
try{ uu/+.9  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); d @*GUmJ  
int nCount = input.readInt(); @_"9Dy Y%  
nStartPos = new long[nCount]; O4g+D#Lu  
nEndPos = new long[nCount]; rx5B=M  
for(int i=0;i<nStartPos.length;i++) `xc^_781\  
{ 7]BW[~77  
nStartPos = input.readLong(); Hi yc#-4  
nEndPos = input.readLong(); Lj"A4i_  
} TP}h~8 /;  
input.close(); R.s^o]vT  
} Ic{F*nnM  
catch(IOException e){e.printStackTrace ();} `g_"GE  
catch(Exception e){e.printStackTrace ();} p)=~% 7DV  
} YqV8D&I  
37q@rDm2  
ZKz,|+X0G  
private void processErrorCode(int nErrorCode) ?6k}ii!c  
{ * FeQ*`r  
System.err.println("Error Code : " + nErrorCode); -@F fU2  
} (Si=m;g  
.,i(2^  
*1'`"D~  
//停止文件下载 QnI.zq V  
public void siteStop() >?]_<:  
{ `Bw9O%]-S  
bStop = true; bC^(U`y32  
for(int i=0;i<nStartPos.length;i++) 9~0^PzTA  
fileSplitterFetch.splitterStop(); ;ml 3  
)%X;^(zKM  
 /q@ s  
} 3s:%2%jVK  
} +'G0{;b  
//负责部分文件的抓取 <|*'O5B  
**FileSplitterFetch.java om3`[r[{  
*/ }%-t+Tf,  
package NetFox; #-"VS-.<  
J@ L9p46,  
S|zW^|YU  
import java.io.*; <X_!x_x  
import java.net.*; v6GsoQmA   
jhGlG-^  
$3d}"D  
public class FileSplitterFetch extends Thread { ;D.h 65rr  
+"ueq  
cM&2SRBZ  
String sURL; //File URL M('d-Q{B7L  
long nStartPos; //File Snippet Start Position y#<MV H  
long nEndPos; //File Snippet End Position npDIX  
int nThreadID; //Thread's ID zD)pF1,7:8  
boolean bDownOver = false; //Downing is over ==H$zmK  
boolean bStop = false; //Stop identical QJW`}`R  
FileAccessI fileAccessI = null; //File Access interface Vi]c%*k  
fIocq  
G2#d $  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Y=*P 8pg  
{ 0fs$#j  
this.sURL = sURL; gFPi7 o1  
this.nStartPos = nStart; = pIy  
this.nEndPos = nEnd; s-W[ .r|  
nThreadID = id; 7dX/bzUVz8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 M0c 9pE  
} o+?r I p  
 UkfB^hA  
W"Jn(:&  
public void run() 8yW oPm<A  
{ %>WbmpIyc  
while(nStartPos < nEndPos && !bStop) e9^2,:wLB  
{ tehUD&  
.5Q:Xp  
l+wc '= ]  
try{ 4.K'\S  
URL url = new URL(sURL); a45 ss7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^# A.@  
httpConnection.setRequestProperty("User-Agent","NetFox"); }E}8_ 8T6  
String sProperty = "bytes="+nStartPos+"-"; jko"MfJ  
httpConnection.setRequestProperty("RANGE",sProperty); 2uk x (Z  
Utility.log(sProperty); cE{ =(OQ  
#)`A7 $/,  
6<5Jq\-h  
InputStream input = httpConnection.getInputStream(); O}#yijU3e  
//logResponseHead(httpConnection); O{k:yVb  
"%@uO)A /  
plV7+?G  
byte[] b = new byte[1024]; DJQglt}~  
int nRead; 8@M'[jT  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) np WEop>  
{ ]$M<]w,IJ2  
nStartPos += fileAccessI.write(b,0,nRead); cUK\x2  
//if(nThreadID == 1) 'FzN[% K"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fMeZ]rb  
} M;Wha;%E"  
0m+8P$)C%  
fj 4^VXD  
Utility.log("Thread " + nThreadID + " is over!"); n~Szf  
bDownOver = true; }~o ikN:  
//nPos = fileAccessI.write (b,0,nRead); qUf)j\7"Fn  
} Z0fJ9 HW  
catch(Exception e){e.printStackTrace ();} &!y]:CC{  
} -U>7 H`5  
} ]=D5p_A(  
{6xPdUhw  
>&H~nGP.  
//打印回应的头信息 t#<KxwhcN  
public void logResponseHead(HttpURLConnection con) hN(L@0)  
{ '5};M)w  
for(int i=1;;i++) b0a}ME&1  
{ L8V3BH7B  
String header=con.getHeaderFieldKey(i); C%ytkzG_  
if(header!=null) 5@XV6  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); hkW{88  
Utility.log(header+" : "+con.getHeaderField(header)); qSQ@p\O~  
else PMKb ]y  
break; 135vZ:S  
} 9DEh*%q  
} jxy1  
2W3W/> 2 h  
$Kq<W{H3ut  
public void splitterStop() B; -2$ 77  
{ [U_[</L7  
bStop = true; 0k?Sq#7q  
} >$ F:*lO  
k_3j '  
qa}>i&uO  
} CtT~0Y|  
;o$;Z4:.D  
;IC'Gq  
/* KtTza5aF  
**FileAccess.java kb|eQtH  
*//文件访问(定位,写) bZ# X 9fT  
package NetFox; F$*3@Y  
import java.io.*; B4O6> '  
=ef1XQ{i*  
h39e)%x1  
public class FileAccessI implements Serializable{ _@E "7<\  
G[q9A$yw  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 g8yN% )[  
RandomAccessFile oSavedFile; _=6OP8  
long nPos; fr#Qz{  
yL"i  
#'>?:k  
public FileAccessI() throws IOException S!7g)  
{ iMWW%@U^=  
this("",0); e~Hr(O+;e6  
} GOW"o"S  
p`GWhI?  
ek[kq[U9  
public FileAccessI(String sName,long nPos) throws IOException :l~EE!  
{ ~|R[O^9B  
oSavedFile = new RandomAccessFile(sName,"rw"); 5.k}{{+  
this.nPos = nPos; >38 Lt\  
oSavedFile.seek(nPos); G&o64W;-s  
} 0VIZ=-e  
k_Tswf3  
1D$::{h  
public synchronized int write(byte[] b,int nStart,int nLen) d_iY&-gq/  
{ baIbf@t/  
int n = -1; l7Lj[d<n  
try{ a`38db(z  
oSavedFile.write(b,nStart,nLen); pb$fb  
n = nLen; $WNG07]tU  
} m;h<"]<  
catch(IOException e) 6{7 3p@  
{ )nnCCR S6  
e.printStackTrace (); L*O>IQh2  
} qG^_c;l6a  
k6J\Kkk(  
1CiA 8  
return n; S$K}v,8.sr  
} M]B3vPA/v  
W^(Iw%ek  
taCCw2s-8*  
} m %Y( O  
F; a3  
l7Y8b`  
/* WFj*nS^~l  
**SiteInfoBean.java O!] ;_q/  
*/ ss; 5C:*y  
package NetFox; S*rO0s:  
`r]TA]D R  
yId;\o B  
public class SiteInfoBean { y.fs,!|%@  
&9@gm--b:  
_vIO !*h0  
private String sSiteURL; //Site's URL fkBLrw  
private String sFilePath; //Saved File's Path 8;8YA1@w  
private String sFileName; //Saved File's Name od(:Y(4  
private int nSplitter; //Count of Splited Downloading File <p)Z/  
#|ddyCg2  
/4H[4m]I  
public SiteInfoBean() fPrb%  
{//nSplitter的缺省值为5 tO4):i1  
//default value of nSplitter is 5 yXXvs'$R \  
this("","","",5); s@ z{dmL  
} 2) ?  
lDlj+fK  
I)rGOda{  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) [%t3[p<)O  
{ 9H[/Tj-;  
sSiteURL= sURL; W'V@  
sFilePath = sPath; Hy;901( %  
sFileName = sName; a! ?.F_T9A  
this.nSplitter = nSpiltter; +h|K[=l\  
n_u`B|^Pj  
UE{,.s  
} }<.7xz|V  
@?Fx  
[='p!7 z  
public String getSSiteURL() aSTFcz"  
{ m'SmN{(t  
return sSiteURL; y3IA '  
} *i%.{ YH  
N tO?  
pY, O_ t$  
public void setSSiteURL(String value) ?-d Ain1w  
{ e"PMvQ  
sSiteURL = value; srsK:%`  
} @7 )Z  
n+X1AOE[L  
fMyE&#}z  
public String getSFilePath() |@+8]dy:l  
{ [qW<D/@  
return sFilePath; zdqnL^wb  
} {f&NStiB  
3y/1!A3  
9E^~#j@Zr  
public void setSFilePath(String value) m,=)qex  
{ .B6`OX&k  
sFilePath = value; QTeFR&q8  
} 8i[".9}G\  
,;7`{Nab  
E3LBPXK  
public String getSFileName() W\'Nv/L  
{ 1Jl{1;c  
return sFileName; 7F=2t_2O  
} P&,hiGTDi  
>/8ru*Oc  
I'xC+nL@  
public void setSFileName(String value) /z..5r^,ZZ  
{ .r7D )xNa@  
sFileName = value; Q6eN+i2 ;  
} ZU)BJ!L,s  
>1m)%zt  
xnT3^ #-h  
public int getNSplitter() lD9%xCo9(  
{ g)X7FxS,z  
return nSplitter; &3WkH W   
} Mp^^!AP9  
4|FRg  
NP$e-" 1  
public void setNSplitter(int nCount) ^v ]UcnB0  
{ `}[VwQ  
nSplitter = nCount; yLjV[ qP  
} +g)_4fV0|  
} N&?T0Ge;  
lt{lHat1  
`i=JjgG@  
/* h-Tsi:%b  
**Utility.java =d}gv6v2S  
*/ *Yj~]E0`1  
package NetFox; \5t`p67Ve_  
ESn6D@"  
D&4u63^  
public class Utility { D~5yj&&T;  
s Ke,  
7U&5^s )J  
public Utility() .4H_Zt[2  
{ 1d/NZJ9  
Po'-z<}wS  
+ylxezc  
} O~${&(  
P/C&R-{')  
//线程睡眠 j?Cr31  
public static void sleep(int nSecond) RP,A!pa@  
{ qUifw @  
try{ _{lx*dq  
Thread.sleep(nSecond); ;,<r|.6U  
} \s.1R/TyD  
catch(Exception e) P#w}3^  
{ r hiS  
e.printStackTrace (); m$7x#8gF  
} +8Of-ZUx  
} m5X3{[a :  
u+I3IdU3  
//日志 wy,Jw3  
public static void log(String sMsg) J"/ JRn  
{ 5dg-d\ 6S  
System.err.println(sMsg); |P^]@om  
} '.]e._T  
, D exJ1  
h9w@oRp`~  
public static void log(int sMsg) <P|`7wfxE  
{ "L9C  
System.err.println(sMsg); N|UBaPS|o  
} jN31\)/i  
} =''mpIg(  
nu#aa#ex>  
-Pqi1pj]  
/* T g3:VD  
**TestMethod.java <I>%m,  
*/ =@Q#dDnFu%  
package NetFox; m Y$nI -P  
U(rr vNt:t  
Ix*BI9E  
public class TestMethod { -@YVe:$%b  
V<7R_}^_7  
zj~8>QnKk  
public TestMethod() ATKYjhc _  
{ ///xx/weblogic60b2_win.exe ^zvA?'s  
try{ 'dmp4VT3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N90\]dFmy  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jHs<s`#h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3C> 2x(]M  
fileFetch.start(); A6{t%k~F  
} Xy[4f=X}z  
catch(Exception e){e.printStackTrace ();} +CsI,Uf4*  
>v^2^$^u  
c+@d'yR  
} o,*folL  
#g@  
4(` 2#  
public static void main(String[] args) cxtLy&C  
{ h g%@W  
new TestMethod(); >{O[t2&  
} l@,);w=_P  
} g0^~J2sDd  
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