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http断点续传简单实现(java)

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/* dC.bt|#Oz  
**SiteFileFetch.java ~6`iY@)  
*/ *5k+t  
package NetFox; wv?RO*E  
import java.io.*; BcQEG *N  
import java.net.*; h}Rx_d  
i?>tgmu.  
0:"2MSf>  
public class SiteFileFetch extends Thread { ?cKZ_c  
VWx]1\  
%MZP)k,&U  
SiteInfoBean siteInfoBean = null; //文件信息Bean IA4N@ijRxh  
long[] nStartPos; //开始位置 .2W"w)$nuq  
long[] nEndPos; //结束位置 1l5J P|x  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 d"E^SBO&  
long nFileLength; //文件长度 0*8TS7.3  
boolean bFirst = true; //是否第一次取文件 ZF6c{~D  
boolean bStop = false; //停止标志 Ipe n  
File tmpFile; //文件下载的临时信息 0K `[,$Y  
DataOutputStream output; //输出到文件的输出流 9CJ(Z+;OM  
"Y;}G lE  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) {u"8[@@./  
public SiteFileFetch(SiteInfoBean bean) throws IOException :@eHX&  
{ H4:&%"j7  
siteInfoBean = bean; s$w;q\1z  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); LlHa5]E@6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); edipA P~!  
if(tmpFile.exists ()) 7I9aG.;  
{ ^{F_ a  
bFirst = false; aI3CNeav  
read_nPos(); 8|@9{  
} e(?]SU|  
else f>2MI4nMG  
{ wM~H(=s`D  
nStartPos = new long[bean.getNSplitter()]; wi_'iv  
nEndPos = new long[bean.getNSplitter()]; 7b[wu~'( n  
} 5'KA'>@  
aUc|V{Jp  
/(hUfYm0  
iEm ?  
} E5</h"1  
M5g\s;y;  
SJ?cI!=x  
public void run() MSw$_d  
{ >yB(lKV  
//获得文件长度 >6<q8{*  
//分割文件 #wY0D_3@1  
//实例FileSplitterFetch _%/}>L>-`8  
//启动FileSplitterFetch线程 .ubE2X[][  
//等待子线程返回 kLj$@E`4  
try{ )5_jmW`n  
if(bFirst) ^7^N}x@  
{ !cSq+eD  
nFileLength = getFileSize(); 'n;OB4  
if(nFileLength == -1) )G~w[~  
{ Ts.wh>`  
System.err.println("File Length is not known!"); 8|6 4R:  
} */^QH@P  
else if(nFileLength == -2) 'Gl&Pa1g?  
{ k D5!}+y  
System.err.println("File is not access!"); |'d>JT:  
} ^uBxgWIC  
else ? *>]")[>  
{ *.#oxcll  
for(int i=0;i<nStartPos.length;i++) :Dt~e|  
{ - e"jw#B  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); up>c$jJ  
}  asHxL!  
for(int i=0;i<nEndPos.length-1;i++) 30>3 !Xqa  
{ *`_{  
nEndPos = nStartPos[i+1]; ZfrVjUB  
} IQZ#-)[T"  
nEndPos[nEndPos.length-1] = nFileLength; 83%)/_&  
} y5r4+2B  
} |`TgX@,#9  
QnQOm ""  
M_g ?<rK  
//启动子线程 Ep9W-n?}  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "]K>j'^Zs<  
for(int i=0;i<nStartPos.length;i++) MN ^Aw9U  
{ Dre2J<QL  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z2_6??tS/c  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $5x ,6[&  
nStartPos,nEndPos,i); ryB}b1`D  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '2^7-3_1  
fileSplitterFetch.start(); >P6BW  
} PHOP%hI $  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0k)rc$eDF+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Q7Iw[=;\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", yAL[[  
nEndPos = " + nFileLength); GZI`jS"lU  
// fileSplitterFetch[nPos.length-1].start(); 'k;rH !R  
wX  >*H  
#$1Z  
//等待子线程结束 ~5FW [_  
//int count = 0; 4}+/F}TbJ5  
//是否结束while循环 Od f[*  
boolean breakWhile = false; .p0Clr!  
HY)-/  
v ~QHMg  
while(!bStop) HK`I\,K  
{ ZKHG!`X0  
write_nPos(); J'$>Gk]  
Utility.sleep(500); @)o^uU T  
breakWhile = true; !?c|XdjZ  
8Nu=^[qwQM  
^nbnbU4'  
for(int i=0;i<nStartPos.length;i++) iQDx{m3]  
{ V"c 6Kdtd  
if(!fileSplitterFetch.bDownOver) Z}$TKO*u  
{ )W/;=K  
breakWhile = false; /1Ue?)g  
break; ck?YI]q|  
} okbQ<{9  
} DC{>TC[p1k  
if(breakWhile) rj(T~d4  
break; }gJ(DbnV  
T5a*z}L5  
h1'\:N`  
//count++; pe^u$YE  
//if(count>4) PRHCrHs  
// siteStop(); Fu!RhsW5j  
} CHe>OreiS  
d3=KTTi\  
sI{ M  
System.err.println("文件下载结束!"); 0 $,SF3K  
} ZK>WW  
catch(Exception e){e.printStackTrace ();} y;s`P .  
} B95B|tU>.  
tH-C8Qxy  
,^uEYT}j  
//获得文件长度 ]]zPq<b2  
public long getFileSize() z^T`x_mF  
{ IiG6<|d8H  
int nFileLength = -1; Lhqz\o  
try{ )wT-8o  
URL url = new URL(siteInfoBean.getSSiteURL()); :j+ ZI3@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z11O F  
httpConnection.setRequestProperty("User-Agent","NetFox"); r-:Uz\gM  
J+`VujWT  
|`.([2  
int responseCode=httpConnection.getResponseCode(); B)0i:"q  
if(responseCode>=400) {{QELfH2  
{ O#F4WWF  
processErrorCode(responseCode); j KoG7HH  
return -2; //-2 represent access is error V$ ps>  
} Z<vKQ4 G  
tCdqh-   
ZpnxecJUJ  
String sHeader; Za 1QC;7  
K*~0"F>"0  
H '  
for(int i=1;;i++) 3f,hw5R  
{ ljb7oA3cP4  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [PDNwh0g5  
//Utility.log(in.readLine()); Q\ 0cvmU  
sHeader=httpConnection.getHeaderFieldKey(i); p>4-s, W  
if(sHeader!=null) dw*_(ys  
{ XCBL}pNkR  
if(sHeader.equals("Content-Length")) >Wv;R2|  
{ A<??T[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); h2XfC. f  
break; 7eAX*Kgt<_  
} NfjE`  
} !6*"(  
else sG F aL  
break; ee^{hQi  
} i%0ur}p  
} :51/29}  
catch(IOException e){e.printStackTrace ();} V6@o]*  
catch(Exception e){e.printStackTrace ();} K1M%!JKh)x  
TA4!$7b$  
E>D_V@,/  
Utility.log(nFileLength); uC(V  
%-1O.Q|f  
Y2~nBb  
return nFileLength; .oeX"6K  
} oU.R2\Q  
kZmpu?P  
l4uMG]m  
//保存下载信息(文件指针位置) NgP&.39U  
private void write_nPos() 2QyV%wz  
{ {#@W)4)cA  
try{ "i[@P)  
output = new DataOutputStream(new FileOutputStream(tmpFile)); RO'7\xvn  
output.writeInt(nStartPos.length); }E50>g  
for(int i=0;i<nStartPos.length;i++) heV=)8  
{ ;z$(nhJ  
// output.writeLong(nPos); hvsWs.;L'  
output.writeLong(fileSplitterFetch.nStartPos); a6)BqlJ  
output.writeLong(fileSplitterFetch.nEndPos); GkQpELO:  
} ?iWi  
output.close(); Ju1D = b  
} @~"h62=] -  
catch(IOException e){e.printStackTrace ();} j~[z2tV  
catch(Exception e){e.printStackTrace ();} H[U!%Z  
} 3cK I  
0tT(W^ho g  
2{H@(Vgpbr  
//读取保存的下载信息(文件指针位置) Dv5D~on{  
private void read_nPos() i#vYyVr[  
{ gc-@"wI?  
try{ G}b]w~ML ~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Lh!J >  
int nCount = input.readInt(); YUtC.TR1  
nStartPos = new long[nCount]; RC7]'4o  
nEndPos = new long[nCount]; T[UN@^DP(  
for(int i=0;i<nStartPos.length;i++) svcK?^ HTe  
{ 5YeM%%-S  
nStartPos = input.readLong(); BBwy,\o#  
nEndPos = input.readLong();  3KlbP  
} gd`!tRcNY  
input.close(); i:Y^{\Z?V  
} +M\`#i\g>  
catch(IOException e){e.printStackTrace ();} iJ1"at  
catch(Exception e){e.printStackTrace ();} 3TeY%5iVt  
} vqDu(6!2  
(MxQ+D\  
MOQ*]fV:  
private void processErrorCode(int nErrorCode) v$?+MNks  
{ | *2w5iR  
System.err.println("Error Code : " + nErrorCode); "n(hfz0y%  
} $P/~rZ@M@  
Vc\MV0lr  
rWa2pO  
//停止文件下载 W$hx,VEy`  
public void siteStop() &=] ~0$  
{ N8F~8lTi  
bStop = true; v&DI`xn~  
for(int i=0;i<nStartPos.length;i++)  ]hk  
fileSplitterFetch.splitterStop(); )r xX+k+b/  
K*K,}W&}  
D#cyOrzy  
} u8&Z!p\  
} lb4Pcd j  
//负责部分文件的抓取 ~ =M7 3U#  
**FileSplitterFetch.java SJb&m-  
*/ . qO@Q=  
package NetFox; 2_HNhW  
B~MU^ |v  
n8~N$tDU  
import java.io.*; +" .X )avF  
import java.net.*; !Xf5e*1IS  
[=6]+V83M  
y\4L{GlBM  
public class FileSplitterFetch extends Thread { s~ a"4~f  
f-vCm 5f  
Dp,L/1GQ8  
String sURL; //File URL 89pEfl j2  
long nStartPos; //File Snippet Start Position %g{X?  
long nEndPos; //File Snippet End Position h7G"G"  
int nThreadID; //Thread's ID _|kxY '_[8  
boolean bDownOver = false; //Downing is over J=9FRC  
boolean bStop = false; //Stop identical P{kur} T  
FileAccessI fileAccessI = null; //File Access interface >JHryS.j$4  
:~&~y-14  
h \fjBDU^  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^ Edfv5  
{ X5zDpi|Dq  
this.sURL = sURL; n{n52][J]  
this.nStartPos = nStart; 36}?dRw#p  
this.nEndPos = nEnd; o4G?nvK-  
nThreadID = id; CGW.I$u  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 lA| 5E?  
} oK6tTK  
(-UYB9s  
[+2[`K c]  
public void run() KKj a/p  
{ aL+ o /  
while(nStartPos < nEndPos && !bStop) T0wW<_jh  
{ HJ=:8:  
_<n~n]%  
ZCMw3]*  
try{ W,V:R  
URL url = new URL(sURL); c69C  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lk/n}bx  
httpConnection.setRequestProperty("User-Agent","NetFox"); q6McGHT  
String sProperty = "bytes="+nStartPos+"-"; &N2N6&Ta/  
httpConnection.setRequestProperty("RANGE",sProperty); ;#g"(  
Utility.log(sProperty); (9''MlGd%  
Q|S.R1L^  
\FQRNj?'_  
InputStream input = httpConnection.getInputStream(); jFQQ`O V  
//logResponseHead(httpConnection); 2V- 16Q'%  
Z3"%`*Tmq-  
(5$!MUS~9  
byte[] b = new byte[1024]; EU2$f  
int nRead; |7'df&CA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *v;2PP[^  
{ -u6bAQ  
nStartPos += fileAccessI.write(b,0,nRead); $O&b``  
//if(nThreadID == 1) 9&-dTayIz  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zqimR#u  
} cvn@/qBq*t  
B nFwlw  
1{)5<!9!l  
Utility.log("Thread " + nThreadID + " is over!"); K[I=6  
bDownOver = true; N]>=p.#j  
//nPos = fileAccessI.write (b,0,nRead); zGb|)A~,  
} F+YZE[h%  
catch(Exception e){e.printStackTrace ();} f',Op1o  
} \j@OZ   
} 1!xQ=DU"  
,Xu-@br{  
xgwY@'GN  
//打印回应的头信息 b1(T4w6  
public void logResponseHead(HttpURLConnection con) >!eAM )  
{ [^WC lRF  
for(int i=1;;i++) Fco`^kql.D  
{ {{$Nqn,pH  
String header=con.getHeaderFieldKey(i); %0S3V[4I  
if(header!=null) t URu0`](  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 5bRJS70M  
Utility.log(header+" : "+con.getHeaderField(header)); m~iXl,r  
else ]J1dtN=  
break; VQc_|z_ s  
} \\iQEy<i  
} &PR5q 7  
rN<0 R`4sE  
R3 -n>V5o  
public void splitterStop() lUOF4U&r  
{ [T8WThs  
bStop = true; F%@A6'c  
} E-T)*`e  
u4t7Ie*Q  
@:oXN]+ _  
} >nJ\BPx  
b)6D_Az7c  
%R}qg6dL  
/* , Rk9N  
**FileAccess.java ax"+0L {  
*//文件访问(定位,写) ^=GC3%  J  
package NetFox; 0!4Ts3qn1  
import java.io.*; LK{*sHi$  
sQYkQ81  
:NhO2L  
public class FileAccessI implements Serializable{ -WY<zJ  
7o7)0l9!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ew>XrT=Zm  
RandomAccessFile oSavedFile; ()Y~Q(5ji  
long nPos; z 9vInf@M  
vk}n,ecl  
OSRp0G20k\  
public FileAccessI() throws IOException dcDyK!zz"  
{ GB23\Yv  
this("",0); Ow+GS{-q  
} GoJ.&aH $  
KI.q@zO6|  
6/f7<  
public FileAccessI(String sName,long nPos) throws IOException k9<;woOBO  
{ 35h 8O,Y  
oSavedFile = new RandomAccessFile(sName,"rw"); 'F/~o1\.  
this.nPos = nPos; 5VfyU8)7X  
oSavedFile.seek(nPos); {0L1X6eg  
}  `xKp%9  
T.])diuvj-  
6Pz4\uE=  
public synchronized int write(byte[] b,int nStart,int nLen) n7zm>&  
{ R"-mKT}  
int n = -1; ^PDJ0k/u1  
try{ zG }@0  
oSavedFile.write(b,nStart,nLen); ?qmRbDI  
n = nLen; "H=6j)Cb  
} 0CWvYC%e  
catch(IOException e) 1XrO~W\=  
{ e2AX0(  
e.printStackTrace (); 5Y.)("1f}f  
} kDEXN  
x,'(5*  
&u]8IEv}u  
return n; } +TORR?  
} 6O7'!@@  
wx]0p  
IQAZuN"<  
} 4svBzZdr  
HCIU!4rH  
|hKDvH  
/* 7!$Q;A  
**SiteInfoBean.java WQx?[tW(U  
*/ c/:b.>W  
package NetFox; ~Zun&b)S  
5-FQMXgThc  
2Sle#nw3  
public class SiteInfoBean { sZ3KT&  
hXcyoZ8  
OyU5DoDz1  
private String sSiteURL; //Site's URL ?so=;gh  
private String sFilePath; //Saved File's Path mu\6z_e  
private String sFileName; //Saved File's Name ]V[q(-Jk  
private int nSplitter; //Count of Splited Downloading File o$wEEz*4  
7z%L*z8V  
C>ICu*PW  
public SiteInfoBean() ~Z-Vs  
{//nSplitter的缺省值为5 j:Xq1f6a  
//default value of nSplitter is 5 Ja|5 @  
this("","","",5); ;"xfOzQ  
} \Q {m9fE  
_jvxc'6  
[xK3F+  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) B+$%*%b  
{ E7WK (  
sSiteURL= sURL; >Ifr [  
sFilePath = sPath; I:E`PZ  
sFileName = sName; MH =%-S   
this.nSplitter = nSpiltter; FDv<\2+ c  
X1:V<,}"  
a Fl;BhM  
} k6;?)~.  
a H yx_B  
Hf%@3X  
public String getSSiteURL() k)i3   
{ W 6^5YH%  
return sSiteURL; ISzqEi  
} $6#CqWhI  
L,HhbTRca  
`A,-@`p  
public void setSSiteURL(String value) #{6{TFx\  
{ /RG:W0=K  
sSiteURL = value; zZ:>do\2  
} |sa]F5  
'g">LQ~a+  
):P?  
public String getSFilePath() # ncRb  
{ l.(v^3:X  
return sFilePath; *o]L|Vu  
} #"}JdBn  
|+{)_?  
?'IP4z;y  
public void setSFilePath(String value) M5i%jZk  
{ [ieI;OG;  
sFilePath = value; 5v[*:0p'  
} 0!D4pvlt  
{k(g]#pP  
hMa]B*o/-  
public String getSFileName() y>S.?H:P  
{ W}nlRbN?  
return sFileName;  50"pbzW  
} dSLU>E3g  
B=U 3  
y3vdUauOn  
public void setSFileName(String value) dR K?~1  
{ bes<qy  
sFileName = value; 4M^= nae  
} oxr#7Ei0d  
yyR0]NzYUD  
pk>^?MO  
public int getNSplitter() &`h{i K7  
{ !'Ak&j1:`  
return nSplitter;  ''|W9!  
} f<GhkDPm>?  
Y h7rU?Gj  
|O3q@  
public void setNSplitter(int nCount) 8aZ=?_gvT  
{ cv8L-Z>x.=  
nSplitter = nCount; 2v:]tj  
} P i=+/}  
} ;$HftG>B  
.28<tEf  
Z~GL5]S  
/* +20G>y=+  
**Utility.java RXNn[A4xfY  
*/ fAF1"4f  
package NetFox; S2E8G q9  
GeI-\F7b  
Cwr~HY  
public class Utility { XWn VgY s  
5CuuG<0  
X3(tuqmi  
public Utility() a,Sw4yJ!Q  
{ =NpYFKmMhV  
FW.7'7G@n  
z Eq GD2"  
} 57aXQ8u{  
\1d (9jR  
//线程睡眠 ~W*FCG#E  
public static void sleep(int nSecond) =pr` '  
{ "7U4'Y:E  
try{ 1f%1*L0>@  
Thread.sleep(nSecond); [2>yYr s_=  
} z__EYh  
catch(Exception e) 4Xgg%@C  
{ >1s* at/h  
e.printStackTrace (); >/{@C  
} 9K.Vb1&  
} 1Vsz4P"O $  
A_V]yP  
//日志 ]E7F /O/.  
public static void log(String sMsg) 3^IpE];+:u  
{ B{/R: Hm  
System.err.println(sMsg); 8Pfb~&X^Ws  
} Y5f1lUT  
Q}`0W[a ~  
@>u}eB>Kn  
public static void log(int sMsg) ,NOsFO-`<  
{ ~Io7]  
System.err.println(sMsg); j_/>A=OD  
} *lYVY) L  
} -^K"ZP1  
Amp#GR1CA  
y?rPlA_  
/* $:BKzHmg  
**TestMethod.java l~1Oef#y  
*/ &]g}u5J!=  
package NetFox; -O1>|y2rU  
26e]`]!SU  
UG'Q]S#!  
public class TestMethod { i% w3/m  
8k2?}/+  
F7 5#*  
public TestMethod() ?e` ^P   
{ ///xx/weblogic60b2_win.exe rTM}})81  
try{ hmvfw:Nq4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Sw:7pByjI  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &[_g6OL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Jk&3%^P{m  
fileFetch.start(); G"klu  
} grS:j+_M2m  
catch(Exception e){e.printStackTrace ();} Mh~q//  
Vl5`U'^qx  
b v G/|U  
} oin$-i|Xp!  
<x@}01 ~  
YO#M/%^j  
public static void main(String[] args) =w;F<M|Y  
{ :Uz|3gq  
new TestMethod(); \O}E7 -  
} g=39C>  
} &?W0mW(  
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