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http断点续传简单实现(java)

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/* ^?]-Q*w3Qs  
**SiteFileFetch.java b IxH0=f  
*/ QiA}0q3]0  
package NetFox; H9'psv  
import java.io.*; c ?<)!9:  
import java.net.*; tKyGD|g S  
I lO,Ql  
s[eSPSFZ  
public class SiteFileFetch extends Thread { Q%~BD@Io  
67/\0mV:~  
3 ;"[WOv  
SiteInfoBean siteInfoBean = null; //文件信息Bean / j "}e_Q  
long[] nStartPos; //开始位置 A *:| d~  
long[] nEndPos; //结束位置 feS$)H9-  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 % u VTf  
long nFileLength; //文件长度 2Y9u9;ah  
boolean bFirst = true; //是否第一次取文件 tz?3R#rM  
boolean bStop = false; //停止标志 wWx{#!W  
File tmpFile; //文件下载的临时信息 iEI#J!~  
DataOutputStream output; //输出到文件的输出流 P9:5kiP H  
FS)# v  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) > jiez,  
public SiteFileFetch(SiteInfoBean bean) throws IOException sk07|9nU  
{ O..{wdZy  
siteInfoBean = bean; 6d5J*y2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); RX{} UmU<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); kWa5=BW2f  
if(tmpFile.exists ()) Y|wjt\M  
{ trjpq{,[U  
bFirst = false; e*`ht+  
read_nPos(); GzaGTd.b  
} s5G`?/  
else }^Sk.:;n3  
{ *@^@7`W  
nStartPos = new long[bean.getNSplitter()]; K:XP;#OsP  
nEndPos = new long[bean.getNSplitter()]; E_'H=QN c  
} V=fh;p  
AB3OG*C9  
sMVk]Mb  
WZHw(BN{+  
} Vp1ct06^  
Nw9:Gi  
UpD4'!<buV  
public void run() %t6-wWM97  
{ >}+R+''nR  
//获得文件长度 :81d~f7  
//分割文件 {A< 961  
//实例FileSplitterFetch ckV\f({  
//启动FileSplitterFetch线程 KkTE -$-  
//等待子线程返回 T(Yp90'6  
try{ w\D !e  
if(bFirst) vw:GNpg'R6  
{ /9gn)q2f(  
nFileLength = getFileSize(); 8PVjNS/  
if(nFileLength == -1) \}4*}Lr  
{ \`z%5/@f;  
System.err.println("File Length is not known!"); 04}8x[t  
} )\D{5j  
else if(nFileLength == -2) f|_\GVW  
{ < @GO]vY  
System.err.println("File is not access!"); 2?6]Xbs{  
} u23_*W\  
else x'\C'zeF  
{ |.m)UFV  
for(int i=0;i<nStartPos.length;i++) S:i# |T."  
{ V'>Plb.A  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ig YYkt  
} a6;[Z  
for(int i=0;i<nEndPos.length-1;i++) -l_B;Sb:e  
{ i5Sya]FN  
nEndPos = nStartPos[i+1]; : qK-Rku  
} |By[ev"Kh%  
nEndPos[nEndPos.length-1] = nFileLength; %,~\,+NP  
} $mAC8a_Zu  
} 5oCg&aT  
~4=*kJ#7  
~@6l7H6{  
//启动子线程 }[lP^Qs  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; jDQ?b\^  
for(int i=0;i<nStartPos.length;i++) - G/qfd|s/  
{ Fx.Ly]L  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ye$j43b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), sCt)Yp+8}B  
nStartPos,nEndPos,i); 9M($_2,44  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); :2M&C+f[  
fileSplitterFetch.start(); 'Nt)7U>oC9  
} VJTO:}Q  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c'3N;sZ*B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `) cH(Rj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", iSoQ1#MP)2  
nEndPos = " + nFileLength); u_+iH$zA  
// fileSplitterFetch[nPos.length-1].start(); u;t~ z  
Y-y yg4JH  
573,b7Yf  
//等待子线程结束 %1jcY0zEQ  
//int count = 0; pZ \7!rON  
//是否结束while循环 T^`; wD  
boolean breakWhile = false; li\=mH,Wr  
JrY*K|YdW  
6i+,/vr  
while(!bStop) -3) jUzD  
{ o<3$|`S&  
write_nPos(); $Z;/Sh  
Utility.sleep(500); pw4^E|X  
breakWhile = true; MIr+4L  
M.s'~S7y  
%c\k LSe  
for(int i=0;i<nStartPos.length;i++) u<cnz% @  
{ ]OdZlZBsJ  
if(!fileSplitterFetch.bDownOver) 4c(Em+ 4  
{ .?QYqGcG  
breakWhile = false; dTK0lgkUE  
break; $fg@g7_:  
} P[G>uA>Z1  
} #>bj6<  
if(breakWhile) M$Z2"F;  
break; B1!xr-kC  
*n EkbI/  
x,U_x  
//count++; E}S%yD[  
//if(count>4) 51y"#\7  
// siteStop(); 8aWEl%  
} h ':ZF  
lTq"j?#E]m  
!YjxCx  
System.err.println("文件下载结束!"); 7CuZ7!>$  
} }kr?+)wB  
catch(Exception e){e.printStackTrace ();} ;XawEG7" U  
} T#3@r0M  
0&]1s  
zM=MFKhi ~  
//获得文件长度 "EMW'>&m  
public long getFileSize() T{3nIF  
{ 7>j~;p{  
int nFileLength = -1; 5a_8`csu  
try{ PgK7CG7G  
URL url = new URL(siteInfoBean.getSSiteURL()); ]r|oNGD)G  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :[_ms d  
httpConnection.setRequestProperty("User-Agent","NetFox"); $+7uB-KsU  
'-RacNY  
}}tbOD)t  
int responseCode=httpConnection.getResponseCode(); Qw'905;(  
if(responseCode>=400) nDC0^&  
{ BXYH&2]Q  
processErrorCode(responseCode); Wj(#!\ 7F  
return -2; //-2 represent access is error 9|}Pf_5]%[  
} thJ~* 0^  
6u+aP  
%;dj6):@  
String sHeader; m]AT-]*f  
oXnaL)Rk  
eyyME c!  
for(int i=1;;i++) esnq/  
{ 6ABK)m-y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [#q>Aq$11  
//Utility.log(in.readLine()); W~ET/h  
sHeader=httpConnection.getHeaderFieldKey(i); (n*:LS=0  
if(sHeader!=null) LQ# E+id&  
{ C{zp8 A(Dh  
if(sHeader.equals("Content-Length")) I8 :e `L  
{ s4"Os gP+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -<6?ISF2  
break; rYr*D[m]  
} |M?vFF]TN  
} kUgfFa#_  
else V3t#kv  
break; R);Hd1G  
} ~bhS$*t64  
} rtj`FH??11  
catch(IOException e){e.printStackTrace ();} \]u;NbC]  
catch(Exception e){e.printStackTrace ();} _2!8,MX  
RTm/-6[N  
clB K  
Utility.log(nFileLength); t+8e?="  
zOs}v{8"  
RPW46l34  
return nFileLength; $mn0I69  
} D=#RQ-  
!=YKfzE  
fu^W# "{  
//保存下载信息(文件指针位置) BHUI1y5t  
private void write_nPos() :dSda,!z  
{ ! ;t\lgMl  
try{ fgdR:@]-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); wu)+n\mt'  
output.writeInt(nStartPos.length); EsMX #1>/m  
for(int i=0;i<nStartPos.length;i++) lhGJ/By- -  
{ v4n< G-  
// output.writeLong(nPos); Vb (b3  
output.writeLong(fileSplitterFetch.nStartPos); kUf i  
output.writeLong(fileSplitterFetch.nEndPos); (aa2uctTn  
} 3T2]V?   
output.close(); @b,Az{EH  
} gA!@oiq@  
catch(IOException e){e.printStackTrace ();} Wb-C0^dTn  
catch(Exception e){e.printStackTrace ();} pd|KIs%jl  
} y QW7ng7D0  
\l~^dn}  
f82%nT  
//读取保存的下载信息(文件指针位置) 7 $e6H|j@  
private void read_nPos() CF '&Yo  
{ >qmCjY1  
try{ Qn!mS[l  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); +i&<`ov  
int nCount = input.readInt(); Q7_5  
nStartPos = new long[nCount]; 3f[Yk# "  
nEndPos = new long[nCount]; .S/ 5kLul  
for(int i=0;i<nStartPos.length;i++) o.{W_k/n  
{ D:1@1Jr  
nStartPos = input.readLong(); e73=*~kfR  
nEndPos = input.readLong(); ^m|@pp  
} l-+=Yk!X  
input.close(); zt(lV  
} 6:ettdj  
catch(IOException e){e.printStackTrace ();} mM,HMrgLqK  
catch(Exception e){e.printStackTrace ();} q>$MqKWM  
} 51jgx,-|$  
R~\R>\  
=yf) Z^  
private void processErrorCode(int nErrorCode) ZZY#.  
{ K~TwyB-h  
System.err.println("Error Code : " + nErrorCode); (~GQncqa  
} C^J<qq &  
.[Sis<A]%  
1M]=Nv  
//停止文件下载  w4U,7%V  
public void siteStop() y{%0[x*N<m  
{ s#9q3JV0  
bStop = true; wFJf"@/vJ  
for(int i=0;i<nStartPos.length;i++) 7~Y\qJ4b  
fileSplitterFetch.splitterStop(); >h\y1IrAaG  
Eomfa:WL  
q[&Kr+)j  
} _K^Q]V[nZ  
} qoO`)<  
//负责部分文件的抓取 4&}%GH>}  
**FileSplitterFetch.java ytZo0pad  
*/ kxMvOB$  
package NetFox; $w0TEO!  
$DY#04Je\=  
2J7|y\N,  
import java.io.*; U#jz5<r  
import java.net.*; @/ z\p7e  
0!hr9Y]Lx  
vK',!1]y  
public class FileSplitterFetch extends Thread { H;/do-W[  
Mog >W&U  
`6Bx8CZ'I  
String sURL; //File URL *~vB6V|1  
long nStartPos; //File Snippet Start Position Er;/ zxg9p  
long nEndPos; //File Snippet End Position %{u@{uG0'3  
int nThreadID; //Thread's ID nip6|dN  
boolean bDownOver = false; //Downing is over )1s5vNVa  
boolean bStop = false; //Stop identical )?F&`+  
FileAccessI fileAccessI = null; //File Access interface DrJ?bG;[  
d:%b  
gHg=G+Q@  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  %?ElC  
{ \|HEe{nA  
this.sURL = sURL; $n\Pw  
this.nStartPos = nStart; ]auvtm- [  
this.nEndPos = nEnd; 'nCVjO7o  
nThreadID = id; AV5={KK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [wGj?M}  
} %K6veB{M  
F@BpAl  
}`uyOgGg*  
public void run() 6"&cQ>$xh  
{ d?zSwLsl  
while(nStartPos < nEndPos && !bStop) 1}(22Q;  
{ BEDkyz;:  
yf&g\ke  
,aP6ct  
try{ ;wn9 21r  
URL url = new URL(sURL); y )QLR<wf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `YNzcn0x  
httpConnection.setRequestProperty("User-Agent","NetFox"); Sdu\4;(  
String sProperty = "bytes="+nStartPos+"-"; {wqT$( (<  
httpConnection.setRequestProperty("RANGE",sProperty); bb6x} jR  
Utility.log(sProperty); (GJtTp~2C4  
gv*b`cl  
OoB|Eh|),  
InputStream input = httpConnection.getInputStream(); eZ'8JU]  
//logResponseHead(httpConnection); IW~R{ ]6  
TM)INo^  
j4$nr=d.6  
byte[] b = new byte[1024]; PLCm\Oh$l  
int nRead; Na0^csPm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) +kL7"  
{ r w?wi}}gn  
nStartPos += fileAccessI.write(b,0,nRead); 6jq*lnA%  
//if(nThreadID == 1) q0.!T0i  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IZZAR  
} (i~UH04r>s  
c4H6I~2Na  
/ Hr|u  
Utility.log("Thread " + nThreadID + " is over!"); B2;P%B  
bDownOver = true; `16'qc  
//nPos = fileAccessI.write (b,0,nRead); 1j?P$%p  
} Y~"tL(WfJl  
catch(Exception e){e.printStackTrace ();} _*mn4n=  
} P5Xp #pa  
} $qNF /rF  
.S k+"iH5  
%2QGbnt_*  
//打印回应的头信息 p{Lrv%-j  
public void logResponseHead(HttpURLConnection con) )z[C=  
{ ,^/Wv!uPE  
for(int i=1;;i++) ]LvP)0=  
{ S\GWMB!oF  
String header=con.getHeaderFieldKey(i); Nq8ON!<<  
if(header!=null) (TZK~+]@sb  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "qmSwdM  
Utility.log(header+" : "+con.getHeaderField(header)); *C_A(n5"V  
else q/s-".%P  
break; K=gg<E<  
} #C9f?fnM  
} f_~T  
dxeiN#(XT  
,/f\  
public void splitterStop() &g :(I  
{ kWr1>})'  
bStop = true; U0&myj 8L  
} _Ewh:IM-  
X=QX9Ux?^  
#V k?  
} "laf:Ty1  
)!8q JQD  
T`# nn|  
/* yYz{*hq  
**FileAccess.java u?,>yf.;s  
*//文件访问(定位,写) 6z\!lOVjb  
package NetFox; a 0SZw  
import java.io.*; v5[gFY(?  
Vn#}f=u\  
!tq]kKJ3:  
public class FileAccessI implements Serializable{ &y? |$p\;/  
|8 ` }8vo)  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ex>7f%\  
RandomAccessFile oSavedFile; 9\8ektq}Z  
long nPos; V(ELrjB0  
xlv(PVdn  
zyPb\/  
public FileAccessI() throws IOException L^qCE-[  
{ w%L4O;E]*{  
this("",0); f I1CT)0<e  
} A7L;ims7  
[4"(\r\f  
 P^te  
public FileAccessI(String sName,long nPos) throws IOException f ,e]jw@  
{ vHi%UaD-y  
oSavedFile = new RandomAccessFile(sName,"rw"); ] (e ,J  
this.nPos = nPos; vu( 5s  
oSavedFile.seek(nPos); A@?0(  
} @b(@`yz.a  
^q-%#  
DOWWG!mx  
public synchronized int write(byte[] b,int nStart,int nLen) F_079~bJ  
{ =z. hJu  
int n = -1; ,!Wo6{'  
try{ 8g -u  
oSavedFile.write(b,nStart,nLen); %n$f#Ml_r  
n = nLen; [{Wo:c9Qq1  
} 6FDj:~  
catch(IOException e) "](Q2  
{ wR_mJMk_  
e.printStackTrace (); 3EYEd39E  
} z</C)ObL  
?NA $<0  
P%R!\i  
return n;  ?s,oH  
} !Q\*a-C  
(BY 0b%^  
lJ3VMYVrUP  
} @ lB{!j&q  
A;8kC}  
4q .;\n  
/* _|e&zr  
**SiteInfoBean.java +.Vh<:?  
*/ <y7{bk~i  
package NetFox; db 99S   
2S7 BzZ/  
x<I[?GT=  
public class SiteInfoBean { 3$"V,_TBZ  
G$,s.MSf  
}[leUYi`  
private String sSiteURL; //Site's URL {XU!p: x  
private String sFilePath; //Saved File's Path l2;$qNAo  
private String sFileName; //Saved File's Name k (AE%eA  
private int nSplitter; //Count of Splited Downloading File N[eL Qe]q  
k -G9'c~  
)2c]Z|  
public SiteInfoBean() *Xnf}Ozx  
{//nSplitter的缺省值为5 ?=lb@U  
//default value of nSplitter is 5 U-DQ?OtmC@  
this("","","",5); +E. D:  
} = cRmaD  
2Pb+/1*ix  
kk5&lak2V  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }"+"nf5h  
{ h GA2.{  
sSiteURL= sURL; G^{~'TZv%  
sFilePath = sPath; "d<uc j  
sFileName = sName; (A=PDjP!  
this.nSplitter = nSpiltter; EY]H*WJJ  
*  1}dk`-  
=x+1A)Q  
} YC;@^  
d>u^ 7:  
& &CrF~  
public String getSSiteURL() _wXT9`|3  
{ ,q%X`F rc  
return sSiteURL; 0WzoI2Q  
} 8b0j rt  
?5't1219  
d"5_x]Z;  
public void setSSiteURL(String value)  IZrcn  
{ Ch{6=k bK  
sSiteURL = value; Lu^uY7 ?}  
} 0`zdj  
oi`L ;w|]  
BcQUD?LC`  
public String getSFilePath() )xf(4  
{ 2MB>NM<xO  
return sFilePath; ajkV"~w',|  
} Q"s6HZ"YI  
Xc+YoA0Ez  
xJ<RQCW$  
public void setSFilePath(String value) ^/Hf$tYI!`  
{ a;dWM(;Kw  
sFilePath = value; Yt*NIwWr  
} .@x.    
(~Bm\Jn  
E uO:}[  
public String getSFileName() B Hp>(7,  
{ ] K&ca  
return sFileName; 6Z1O:Bou  
} `yq) y>_  
pS-o*!\C.  
r;b`@ .  
public void setSFileName(String value) n<|8Onw  
{ gna!Q  
sFileName = value; q=e;P;u  
} =P,mix|  
V|A.M-XLv4  
c611&  
public int getNSplitter() ]u<U[l-w  
{ D(Z#um8n  
return nSplitter; y}FG5'5$13  
} xN$V(ZX4  
fFVQu\  
/Gnt.%y&  
public void setNSplitter(int nCount) {{gd}g  
{ k6DJ(.n'%a  
nSplitter = nCount; IM6n\EZ^  
} +z9BWo!{I  
} 1c/<2xO~  
}JOz,SQHP  
>=rniHs=?7  
/* iuqJPW^}  
**Utility.java >r)UDa+  
*/ _s-X5 xU  
package NetFox; Y,mo}X<>  
OWz{WV.  
p\I3fI0i  
public class Utility { U(+QrC:  
ph)=:*A6&  
?mV2|;  
public Utility() OWfB8*4@  
{ Te!eM{_$T  
fFC9:9<  
aiX4;'$x!  
} f dJg7r*  
LDw.2E  
//线程睡眠 zZ9Ei-Q  
public static void sleep(int nSecond) Yrf?|,  
{ 4]zn,g?&  
try{ 902A,*qq  
Thread.sleep(nSecond); EhD%  
} cMtUb  
catch(Exception e) QHXpX9  
{ _eQ-'")  
e.printStackTrace (); b* n#XTV  
} N1E9w:T`  
} X`Lv}6}xT  
L#D)[v"  
//日志 =.J>'9Q  
public static void log(String sMsg) -q)|I|y*7  
{ U3aM^  
System.err.println(sMsg); \p\p~FVS  
} 1 h162  
<Qbqxw  
u6E ze4u  
public static void log(int sMsg) +yr~UP_ }  
{ D}{]5R  
System.err.println(sMsg); bA6^R If?  
} x`p908S^  
} -NzOX"V]3  
!}`[s2ji  
V LeYO5'L  
/* }!*|VdL0  
**TestMethod.java nR Hl Hu  
*/ )g&nI <Mh  
package NetFox; u,@ac[!vP  
va(6?"9  
$^e_4]k  
public class TestMethod { p&xj7qwp@F  
"FE%k>aV@v  
f/kYm\Zc  
public TestMethod() #~rQ\A!4  
{ ///xx/weblogic60b2_win.exe 7k#>$sY+  
try{ ;$*tn"- ?~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); KB\ri&bF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); _=[pW2p  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E^w0X,0XlE  
fileFetch.start(); 0ikA@SAq  
} =L"I[  
catch(Exception e){e.printStackTrace ();} e=tM=i"  
Z0~,cO8~  
e v7A;;  
} H11@ DQ6  
fA V.Mj-  
VK%ExMSqEh  
public static void main(String[] args) PJKxh%J  
{ {poTA+i  
new TestMethod(); m,4'@jg0  
} uW(Ngcpr  
} L]X Lv9J0  
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