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http断点续传简单实现(java)

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/* ih?^t(i  
**SiteFileFetch.java ?"?6,;F(4  
*/ hhoEb(BA  
package NetFox; f+rz|(6vs{  
import java.io.*; GGhM;%H_99  
import java.net.*; .]aF 1}AI  
Hw#d_P:  
Sa19q.~%  
public class SiteFileFetch extends Thread { Ra*e5  
kB5.(O  
NrP0Ep%V  
SiteInfoBean siteInfoBean = null; //文件信息Bean p ?wI9GY  
long[] nStartPos; //开始位置 cb5,P~/q  
long[] nEndPos; //结束位置 2Z20E$Cb  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7d92 Pe  
long nFileLength; //文件长度 [{C )LDN  
boolean bFirst = true; //是否第一次取文件 qj cp65^  
boolean bStop = false; //停止标志 ]%Zz \Q  
File tmpFile; //文件下载的临时信息 P{Q=mEQ  
DataOutputStream output; //输出到文件的输出流 FKe,qTqa  
s;UH]  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) PRNoqi3sY  
public SiteFileFetch(SiteInfoBean bean) throws IOException Kx_h1{  
{ ]Qm]I1P  
siteInfoBean = bean; @ 49nJi  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); fDx9iHGv  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !n6wWl  
if(tmpFile.exists ()) sg E-`#  
{ s+:=I e  
bFirst = false; =2w4C_  
read_nPos(); pm{|?R  
} r! Ay :r  
else Y.^=]-n,  
{ 5BBD.!  
nStartPos = new long[bean.getNSplitter()]; /%lZu^  
nEndPos = new long[bean.getNSplitter()]; {BHI1Uw  
} pRSOYTebP  
Gycm,Cy  
dg4vc][  
[]s^   
} l }XU 59  
bI|2@H V2  
vM_:&j_?``  
public void run() )}9rwZ  
{ xC C:BO`pw  
//获得文件长度 t43)F9!  
//分割文件 u{["50~  
//实例FileSplitterFetch a#T]*(Yq)  
//启动FileSplitterFetch线程 MQin"\  
//等待子线程返回 {nU=%w"\  
try{ V ]90  
if(bFirst) OzC\9YeA  
{ v@#b}N0n  
nFileLength = getFileSize(); [ @4rjGwB  
if(nFileLength == -1) HYmn:?H  
{ s`>[F@N7.o  
System.err.println("File Length is not known!"); -GLMmZJt  
} l3 DYg  
else if(nFileLength == -2) 1#1 riM -  
{ svXR<7) #  
System.err.println("File is not access!"); /PsnD_s]5  
} 1yqJwy;X  
else +VQ\mA59  
{ oPPX&e@=s]  
for(int i=0;i<nStartPos.length;i++) C!7>1I~5  
{ <]G]W/eB'  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); B7]MGXC  
} ]vuwkn+)  
for(int i=0;i<nEndPos.length-1;i++) _ 84ut  
{ /rSH"$  
nEndPos = nStartPos[i+1]; F5o+kz$;  
} TwgrRtj'  
nEndPos[nEndPos.length-1] = nFileLength; } (!EuLL  
} ,!U=|c"k)  
} |^@dFOz  
ul*Qt}  
"O(9m.CZ  
//启动子线程 }pJwj  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "1, pHR-+R  
for(int i=0;i<nStartPos.length;i++) 0T46sm r  
{ ;qBu4'C)T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T9s2bC.z55  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @g G<le6  
nStartPos,nEndPos,i); ES40?o*]x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8zMu7,E  
fileSplitterFetch.start(); IT$25ZF  
} t]X w{)T  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2<}NB?f`N  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); n9s iX  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $[yFsA6  
nEndPos = " + nFileLength); j!3 Gz  
// fileSplitterFetch[nPos.length-1].start(); Uo2GK3nT  
;`6^6p\p  
|2KAo!PI  
//等待子线程结束 cp o-.  
//int count = 0; U)3DQ6T99  
//是否结束while循环 ]KJj6xn  
boolean breakWhile = false; R i^[i}  
`Qqk<o  
W2.qhY5  
while(!bStop) vv=VRhwF  
{ /q5:p`4{J  
write_nPos(); IUwm}9Q!  
Utility.sleep(500); ]Zmj4vK J  
breakWhile = true; (T2m"Yi:  
~}<DG1!  
H9CS*|q6r  
for(int i=0;i<nStartPos.length;i++) B,{K*-7)MX  
{ be +4junf  
if(!fileSplitterFetch.bDownOver) +a*tO@HG  
{ \G-KplKS  
breakWhile = false; #UbF9})q  
break; cH>%r^G\  
} R+CM`4CD  
} O|w J)  
if(breakWhile) nR`ov1RH  
break; ;amXY@RmH  
B7!3-1<k>  
!o$!Frc  
//count++; aE2.L;Tk?  
//if(count>4) M|R b&6O  
// siteStop(); x*/S*!vx\  
} oJfr +3I  
5L!y-3  
tToTxf~  
System.err.println("文件下载结束!"); 7nuU^wc  
} `]W| 8M  
catch(Exception e){e.printStackTrace ();} |6< p(i7  
} L`24 ?Y{  
Z4\=*ic@  
w4gg@aO  
//获得文件长度 6R^^.tCs  
public long getFileSize() 8-O)Xx}cU  
{ LGtIm7  
int nFileLength = -1; k1!@^A  
try{ Sy 'Dp9!|  
URL url = new URL(siteInfoBean.getSSiteURL()); ow]053:i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); D gaMO,  
httpConnection.setRequestProperty("User-Agent","NetFox"); $ , u+4h  
X*\ J_  
#{\%rWnCm  
int responseCode=httpConnection.getResponseCode(); /Sh#_\x  
if(responseCode>=400) 6AhM=C  
{ S;- LIv  
processErrorCode(responseCode); ctGL-kp  
return -2; //-2 represent access is error GN2Sn` ;  
} yNbjoFM.i  
pfI"36]F  
Nal9M[]c  
String sHeader; jB(|";G  
9B9(8PVG  
5^x1cUB]  
for(int i=1;;i++) y_?Me]  
{ j?+X\PtQ  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -jiG7OL  
//Utility.log(in.readLine()); OtNd,U.dE  
sHeader=httpConnection.getHeaderFieldKey(i); 1 9CK+;b  
if(sHeader!=null) n<u $=H  
{ X)% A6M  
if(sHeader.equals("Content-Length")) qXwPDq/  
{ &mx)~J^m  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Dg?:/=,=9r  
break; Bf8jPa/  
}  v%iflCK  
} ;-qO'V:;  
else ~W-PD  
break;  .P"D  
} c(~[$)i6  
} IqoR7ajA  
catch(IOException e){e.printStackTrace ();} 5wDg'X]>V  
catch(Exception e){e.printStackTrace ();} XD2v*l|Po  
)'+8}T]xQ  
WA&!;Zq  
Utility.log(nFileLength); <Pi|J-Y  
_+E5T*dk  
ilqy /fL#  
return nFileLength; qO|R^De  
} m*kl  
|mw.qI|  
=UfsL%  
//保存下载信息(文件指针位置) W*I(f]8:y`  
private void write_nPos() ?o|f':  
{ mmk=97  
try{ #iHs* /85  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Ev}C<zk*  
output.writeInt(nStartPos.length); TJR:vr  
for(int i=0;i<nStartPos.length;i++) fNW"+ <W  
{ 0a XPPnuX  
// output.writeLong(nPos); ]Yn_}Bq  
output.writeLong(fileSplitterFetch.nStartPos); Y<%@s}zc  
output.writeLong(fileSplitterFetch.nEndPos);  UWo]s.  
} pz.JWCU1  
output.close(); XLrwxj0  
} }*S `qW;B  
catch(IOException e){e.printStackTrace ();} yvO{:B8%  
catch(Exception e){e.printStackTrace ();} YF>m$?;  
} #6HA\dE  
t,+nQ9  
wG-HF'0L  
//读取保存的下载信息(文件指针位置) 85Otss/mM  
private void read_nPos() R[hzMU}KB  
{ 4J/}]Dr5  
try{ 4?q <e*W  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >]vlkA(  
int nCount = input.readInt(); 2OVRf0.R~  
nStartPos = new long[nCount]; waj0"u^#  
nEndPos = new long[nCount]; =E#%'/ A;c  
for(int i=0;i<nStartPos.length;i++) vkEiOFU!u  
{ sW'2+|3"  
nStartPos = input.readLong(); T~##,qQ  
nEndPos = input.readLong(); ;"~ fZ2$U  
} x#xFh0CA  
input.close(); j~jV'f.:H  
} =*c7i]@}  
catch(IOException e){e.printStackTrace ();} /n{omx  
catch(Exception e){e.printStackTrace ();} A#J`;5!Sc  
} >8#X;0\Kj  
SPY|K  
ORJIo  
private void processErrorCode(int nErrorCode) mQ|v26R  
{ g'n7T|h ~  
System.err.println("Error Code : " + nErrorCode); 9\mLW"  
} Vg>dI&O  
ic#`N0s?  
MS 81sN\d  
//停止文件下载 8h*Icf  
public void siteStop() tne ST.  
{ L"1}V  
bStop = true; #(N+(():  
for(int i=0;i<nStartPos.length;i++) f$Fhf ?'  
fileSplitterFetch.splitterStop(); qGB{7-ru  
yDegcAn?  
Kzm+GW3o[  
} AicBSqUke  
} R\G0'?h >  
//负责部分文件的抓取 bU2Z[sn.  
**FileSplitterFetch.java YA_c N5p/@  
*/ IID-k  
package NetFox; zck#tht4 n  
CR"|^{G  
1AM!8VR2  
import java.io.*; $!-c-0ub  
import java.net.*; R6kD=JY/!  
4gz H8sF  
K<SyC54  
public class FileSplitterFetch extends Thread { ( u\._Gwsx  
7e|s wJ>4  
0zlb0[  
String sURL; //File URL q1"$<# t  
long nStartPos; //File Snippet Start Position F@'Jbd`   
long nEndPos; //File Snippet End Position BW}U%B^.  
int nThreadID; //Thread's ID W14 J],{L  
boolean bDownOver = false; //Downing is over !Sh&3uy_qN  
boolean bStop = false; //Stop identical p6#g;$V$  
FileAccessI fileAccessI = null; //File Access interface i1NY9br  
t\~P:"  
|y!=J$ $_H  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException /v1Q4mq  
{ w[zjerH3  
this.sURL = sURL; =hC,@R>;  
this.nStartPos = nStart; 93("oBd[s(  
this.nEndPos = nEnd; 1{ ~#H<K  
nThreadID = id; p.v0D:@&  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 s E2D#D  
} 8 D3OOab  
mS$j?>m  
K/j3a[.  
public void run() A@1W}8qY:  
{ F4}]b(L  
while(nStartPos < nEndPos && !bStop) Z<1FSk,[  
{ -:Da&V  
0WZ_7C?  
-Ta9 pxZk  
try{ Xqg@ e:g  
URL url = new URL(sURL); Ce9|=Jx!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "GMBjT8  
httpConnection.setRequestProperty("User-Agent","NetFox"); P;=n9hgHI  
String sProperty = "bytes="+nStartPos+"-"; B}Z63|/N  
httpConnection.setRequestProperty("RANGE",sProperty); MDhRR*CBh  
Utility.log(sProperty); |:q=T ~x  
8<S~Z:JK  
lYVz 3p  
InputStream input = httpConnection.getInputStream(); %Gz0^[+  
//logResponseHead(httpConnection); )t0$qd ]  
ZkRx1S"m  
rzhWw-GY  
byte[] b = new byte[1024]; \o}xF@sM5  
int nRead; z;{iM/Xe  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %p^wZtm  
{ 8=B|C'>  
nStartPos += fileAccessI.write(b,0,nRead); :DrWq{4  
//if(nThreadID == 1) nBjqTud  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [R(`W#W  
} Y!~49<;  
+7D|4  
0=@?ob7  
Utility.log("Thread " + nThreadID + " is over!"); bv]`!g: C  
bDownOver = true; S!jTyY7e  
//nPos = fileAccessI.write (b,0,nRead); /32Fy`KV  
} X@ +{5%  
catch(Exception e){e.printStackTrace ();} A-Sv;/yD_  
} L-jJg,eY  
} bhTb[r  
u)X=Qm)  
,&]S(|2%>t  
//打印回应的头信息 3 }TaF~  
public void logResponseHead(HttpURLConnection con) >Ea8G,  
{ ~ -4{B  
for(int i=1;;i++) 4IB9 ,?p  
{ p `8 s  
String header=con.getHeaderFieldKey(i); 0bceI  
if(header!=null) .0S~872  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Uol|9F  
Utility.log(header+" : "+con.getHeaderField(header)); 1n >X[! 8x  
else AF;)#T<  
break; rn/ /%  
} <r .)hT"0  
} bR*-Ht+wd  
KyVQh8  
Y}t \4 di  
public void splitterStop() +X#vVD3"  
{ "cE7 5  
bStop = true; V]|^&A _c  
} Q8:Has  
!o5 W  
^W`<gR  
} 5A)2} D]  
|4)>:d  
;,C)!c&  
/* WZ-s--n#  
**FileAccess.java 0t^M3+nc  
*//文件访问(定位,写) ?J%1#1L"/  
package NetFox; B-?6M6#  
import java.io.*; h;C5hU 4P  
L"E7#}  
j@W.&- _  
public class FileAccessI implements Serializable{ '-r).Xk  
6LOnU~l,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &vo--V1|  
RandomAccessFile oSavedFile; 9v;Vv0k_  
long nPos; Od)Uv1  
H{@Yo\J  
#o=y?(  
public FileAccessI() throws IOException b(*!$EB  
{ ?x$"+,  
this("",0); i2@VB6]?  
} }\z.)B4,  
RJL2J]*S  
v6=RY<l"m  
public FileAccessI(String sName,long nPos) throws IOException RHaI~jb  
{ _D+}q_  
oSavedFile = new RandomAccessFile(sName,"rw"); )#BMTKA^  
this.nPos = nPos; NTdixfR  
oSavedFile.seek(nPos); (_niMQtF}  
} \a5U8shc  
]9YJ,d@J  
$yn];0$J  
public synchronized int write(byte[] b,int nStart,int nLen) 8UW^"4  
{ J ][T"K  
int n = -1; q-  
try{ W^0w  
oSavedFile.write(b,nStart,nLen); jlkmLcpf  
n = nLen; 3p3 9`"~  
} @KWb+?_H{<  
catch(IOException e) H35S#+KX  
{  J}htu  
e.printStackTrace (); 3/aMJR:o  
} Hc!  mB  
B( ]M&  
i'a?kSy  
return n; .\[`B.Q  
} xAqb\|$^  
w zYzug  
K0H'4' I  
} NE"@Bk cm  
p6 ]7&{>  
xO$lsZPG  
/* $:cE ^8K  
**SiteInfoBean.java  tR}MrM  
*/ C\3y {s  
package NetFox; ~8~aJ^[  
c2h{6;bfY  
&qMPq->  
public class SiteInfoBean { w:%o?pKet1  
hXfQ)$J  
H(R1o~  
private String sSiteURL; //Site's URL I CZ4 A{I  
private String sFilePath; //Saved File's Path CpA|4'#  
private String sFileName; //Saved File's Name qS403+Su1=  
private int nSplitter; //Count of Splited Downloading File dq7x3v^"ZG  
bHPYp5UwN  
y-T| #  
public SiteInfoBean() ^M3~^lV  
{//nSplitter的缺省值为5 )` SE S."  
//default value of nSplitter is 5 !Nu<xq@!  
this("","","",5); ?p9VO.^5  
} fdxLAC  
VO,!x~S!  
RS"H8P 4W  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e>7]w,*|  
{ u}>#Eb  
sSiteURL= sURL; )'Oh `$M  
sFilePath = sPath; $56Z#'(D  
sFileName = sName;  V_C-P[2~  
this.nSplitter = nSpiltter; AjmVc])  
B\<Q ;RI2;  
Ao&\EcIOT  
} G'rxXJq  
IC#>X5  
D;oe2E{I  
public String getSSiteURL() +!k&Yje  
{ H9KKed47d/  
return sSiteURL; N8!cO[3Oh  
} {s)+R[?m<o  
p`mS[bxv!  
~3UQ|j  
public void setSSiteURL(String value) AK&S5F>D+B  
{ &J55P]7w  
sSiteURL = value; R?v>Q` Qi  
} Tu@8}C  
;lq;X{/  
,/YF-L$(t  
public String getSFilePath() {_b%/eR1  
{ mYxuA0/k  
return sFilePath; il}%7b-  
} <DMl<KZ  
vh"R'o  
kUq=5Y `D  
public void setSFilePath(String value) W!%]_I!&K  
{ ` BDLW%aL  
sFilePath = value; 0n@rLF  
} ^:K3vC[h;c  
unshH<  
FjK3 .>'  
public String getSFileName() m*ISa(#(,  
{ ]P#XVDn+;  
return sFileName; H70LhN  
} 8j Mk)-  
@'YS1N<  
@L>q (Kg  
public void setSFileName(String value) &/mA7Vf>eR  
{ nS/)P4z  
sFileName = value; d1T,eJ}  
} B,M(@5wz  
UV5Ie!\nm  
1lq(PGX)  
public int getNSplitter() %F\?R[^5  
{ zBo1P(kek  
return nSplitter; f _[<L  
}  i7]4W  
t/ +=|*  
-0?~  
public void setNSplitter(int nCount) 7P" | J\  
{ :Nu^  
nSplitter = nCount; M54j@_81pX  
} H:!7:  
} >G);j@Q  
g1XZ5P} f  
S7=Bd[4  
/* q+P|l5_ t  
**Utility.java aT_&x@x  
*/ 8S>&WR%jH]  
package NetFox; ([ jF4/  
`n$I]_}/%  
%R@X>2l/_  
public class Utility { 7+]=-  
`^bgUmJ~  
D-8O+.@  
public Utility() 6WV\}d:  
{ GMMp|WV|  
+ hn+K1  
@b"t]#V(E  
} ZPiq-q  
}MRd@ 0-?!  
//线程睡眠 MHSs!^/g5  
public static void sleep(int nSecond) tYZ[6 8  
{ }Mo=PWI1?  
try{ _Xnqb+  
Thread.sleep(nSecond); Is]aj-#r  
} ]GN7+ 8l  
catch(Exception e) ^ s1Q*He  
{ *&?c(JU;<  
e.printStackTrace (); O?U'!o=  
} Nndddk`  
} ?dD&p8{  
! vP[;6  
//日志 f~Fm4 >\(  
public static void log(String sMsg) hy}8Aji&  
{ $wmvKQc{lx  
System.err.println(sMsg); CF+_/s#j^  
} &n6$rBr %  
U"q/rcA  
S>.SSXlM  
public static void log(int sMsg) s4 6}s{6   
{ t=_J9|  
System.err.println(sMsg); 1"/He ` 4  
} Sl-v W  
} Ul2R'"FB  
!,[C] Q1  
=Vy`J)z9  
/* '3TW [!m  
**TestMethod.java Xv< B1  
*/ @?=|Y  
package NetFox; N` aF{3[  
HHq_P/'  
q6_u@:3u  
public class TestMethod { nA P.^_K  
BYs-V:  
FL(6?8zK  
public TestMethod() \"CZI<=TB  
{ ///xx/weblogic60b2_win.exe Gp4A.\7  
try{ 2WtRJi?b|  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #+$G=pS'v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); MS0Fl|YA  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?CC"Yij  
fileFetch.start(); 356>QW'm  
} KN7^:cC  
catch(Exception e){e.printStackTrace ();} )K,F]fc+O  
p"l3e9&'j  
6)vSG7Ise  
} jV? }9L^;  
TUHi5K  
mN!lo;m5  
public static void main(String[] args) h~(G$':^  
{ L]d-hs  
new TestMethod(); t5'V6nv  
} S,<EEtXQ  
} wY~&Q}U  
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