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http断点续传简单实现(java)

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/* TTu<~GH  
**SiteFileFetch.java Xji<oih  
*/ '9*(4/,UJJ  
package NetFox; tKu'Q;J  
import java.io.*; kbiMqiPG  
import java.net.*; /dj r_T  
d/N&bTg:  
P6@(nGgK<  
public class SiteFileFetch extends Thread { !Yd7&#s  
!bRoNP  
UhXZ^ k3  
SiteInfoBean siteInfoBean = null; //文件信息Bean SCZtHEl9  
long[] nStartPos; //开始位置 Yq}(O<ol  
long[] nEndPos; //结束位置 $3w a%"  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 +O2T%  
long nFileLength; //文件长度 ~}PB&`%7  
boolean bFirst = true; //是否第一次取文件 CB:G4VqOT  
boolean bStop = false; //停止标志 @.@O#  
File tmpFile; //文件下载的临时信息 |]*]k`o<)  
DataOutputStream output; //输出到文件的输出流 #[ipJ %  
{ LZ` _1D  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Dz3=ksXZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException @WEDXB  
{ IXc"gO  
siteInfoBean = bean; bC&*U|de  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *`7cvt5]IM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7G z f>n  
if(tmpFile.exists ()) fIWOo >)D  
{ 4'_PLOgnX  
bFirst = false; EPkmBru ^  
read_nPos(); .0}]/%al  
} tUaDwIu#  
else PS7ta?V QC  
{ S&^i*R4]  
nStartPos = new long[bean.getNSplitter()]; Xz4T_-X8d  
nEndPos = new long[bean.getNSplitter()]; E>NRC\^@  
} B"P-h^oiV  
%a$ l%8j&  
-C1,$mkj  
sT ]JDC6  
} K*NCIIDh  
s"gNHp.oF  
W"MwpV  
public void run() {$5?[KD  
{ > yk2  
//获得文件长度 ?%K7IJ%  
//分割文件 VB=$D|Ll  
//实例FileSplitterFetch #6* j+SX^  
//启动FileSplitterFetch线程 l3[2b Qx  
//等待子线程返回 U|Z Yoc+](  
try{ W:VRLT>w>  
if(bFirst) 3g ep_ aC  
{ 41dB4Td5t  
nFileLength = getFileSize(); :QGgtTEV""  
if(nFileLength == -1) tX)l_ ?jVH  
{ R+}7]tva6C  
System.err.println("File Length is not known!"); N/CL?Z>c  
} ny'?Hl'Q  
else if(nFileLength == -2) U|yXJ.Z3  
{ vM5yiHI(jb  
System.err.println("File is not access!"); F8Y_L\q  
} \%[sv@P9s  
else dPvRbwH<  
{ _3YZz$07  
for(int i=0;i<nStartPos.length;i++) jjLx60|{  
{ oU"!"t  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~FCkr&Ky3  
} u2\QhP 9  
for(int i=0;i<nEndPos.length-1;i++) apy9B6%PJ+  
{ ;@/^hk{A  
nEndPos = nStartPos[i+1]; iX (<ozH  
} ZMa@/\pf1  
nEndPos[nEndPos.length-1] = nFileLength; x6N)T4J(  
} |0^~S  
} M it3q  
FglW|Hwy  
.! 'SG6 q  
//启动子线程 {/ef`MxV }  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Y-YlQ ^  
for(int i=0;i<nStartPos.length;i++) ,v\^efc:%  
{ |f67aN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1xBgb/+  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), GoSdo  
nStartPos,nEndPos,i); 7H=V|Btnc  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9:9gam  
fileSplitterFetch.start(); p#;I4d G  
} :}0>IPW-V  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ; ,9:1.L  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9^+8b9y  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Bl$Hg,in-  
nEndPos = " + nFileLength); "($"T v2  
// fileSplitterFetch[nPos.length-1].start(); ;+;%s D  
P z< \q;  
"WF@T  
//等待子线程结束 (Y!{ UNq5  
//int count = 0; +YD_ L  
//是否结束while循环 0)Nu  
boolean breakWhile = false; +%sMd]$,n  
!94qF,#1  
Gv\39+9 =  
while(!bStop) i0q<,VSl$_  
{ ! mb<z^>5  
write_nPos(); ^ jYE4gHM  
Utility.sleep(500); " i!Xiy~  
breakWhile = true; cZR9rnZT  
4(nwi[1Y  
@h=r;N#/`P  
for(int i=0;i<nStartPos.length;i++) |X47&Y  
{ %^KNY ;E  
if(!fileSplitterFetch.bDownOver) [%LIW%t|  
{ 5.M82rR; ~  
breakWhile = false; 2e?a"Vss  
break; T"_f9?  
} 3q-Xj:FP  
} 9 `+RmX;m  
if(breakWhile) i&m t-  
break; 'f_[(o+n  
8{4SaT.-Rm  
,II-:&H  
//count++; *G&3NSM-  
//if(count>4) i K,^|Q8  
// siteStop(); ]iezwz`'  
} r7FFZNs!  
\DMZ M  
qbx}9pp}g  
System.err.println("文件下载结束!"); 89Ch'D  
} ioT+,li  
catch(Exception e){e.printStackTrace ();} }}b &IA#  
} +wIv|zj9  
[cso$Tv  
6^vz+oN  
//获得文件长度 HRg< f= oz  
public long getFileSize() 9M;k(B!  
{ 2A&Y})D  
int nFileLength = -1; b|Sjh;  
try{ ?v,4seRuz  
URL url = new URL(siteInfoBean.getSSiteURL()); S;tv4JY  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lvp8{]I<  
httpConnection.setRequestProperty("User-Agent","NetFox"); M$Or|HTG  
fx=HKt  
l1UN.l'p  
int responseCode=httpConnection.getResponseCode(); ~O8Xj6  
if(responseCode>=400) ;d<RP VE:  
{ sjj,q?  
processErrorCode(responseCode); s;W1YN  
return -2; //-2 represent access is error L %20tm  
} UPcx xtC  
{?uG] G7  
'U*Kb  
String sHeader; $s<bKju  
AGMrBd|J{  
.azA1@V|  
for(int i=1;;i++) M0K+Vz=  
{ hQ_g OI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !SAR/sdXf  
//Utility.log(in.readLine()); St|B9V?eEB  
sHeader=httpConnection.getHeaderFieldKey(i); qr'P0+|~5  
if(sHeader!=null) v=J[p;H^H  
{ eh /QFm 4  
if(sHeader.equals("Content-Length")) >5MHn@  
{ Oi4y~C_Xd  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); e)#f`wM  
break; NR.YeKsBq  
} -F&*>?I  
} lG R6S  
else chszP{-@X  
break; D:#e;K  
} ' }T6dS  
} wvz_)b N~A  
catch(IOException e){e.printStackTrace ();} cr>"LAi  
catch(Exception e){e.printStackTrace ();} a&C}' e"  
&O\$=&, h  
JW9U&Bj{  
Utility.log(nFileLength); &Xp<%[:  
\(;X3h  
9-hVlQ~|  
return nFileLength; EZ)$lw/!J  
} wq>0W 4(  
I%tJLdL  
:>o2UH  
//保存下载信息(文件指针位置) !8}x6  
private void write_nPos() 0u=FlQ }h  
{ k|; [)gE  
try{ o l8|  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Rdl^-\BV  
output.writeInt(nStartPos.length); rssn'h  
for(int i=0;i<nStartPos.length;i++) @f%q ,:  
{ hx:"'m5  
// output.writeLong(nPos); k*k 9hv?  
output.writeLong(fileSplitterFetch.nStartPos); |YWX.-aeo  
output.writeLong(fileSplitterFetch.nEndPos); [fIElH<  
} g3kF&+2i  
output.close(); $[M5V v  
} YdF\*tZ  
catch(IOException e){e.printStackTrace ();} *,#T&M7D  
catch(Exception e){e.printStackTrace ();} [*z`p;n2D  
} o}6d[G>  
B`/p[U5  
,#hx%$f}d  
//读取保存的下载信息(文件指针位置) ZE4xF8  
private void read_nPos() $94l('B6H  
{ ZuVes?&j  
try{ <69Uq8GI  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); by@}T@^\  
int nCount = input.readInt(); 3fhlMOm  
nStartPos = new long[nCount]; =plU3D2  
nEndPos = new long[nCount]; v6*8CQ+  
for(int i=0;i<nStartPos.length;i++) m)"wd$O^w  
{ Pj7n_&*/  
nStartPos = input.readLong(); "Oq>i9v;|$  
nEndPos = input.readLong(); gvy c(d  
} D.Z4noMA6  
input.close(); t`eUD>\  
} C?fa-i0l^  
catch(IOException e){e.printStackTrace ();} xSL%1>MrN  
catch(Exception e){e.printStackTrace ();} lbnH|;`$]m  
} &'A8R;b}-?  
+X4/l"|  
m6YDyQC  
private void processErrorCode(int nErrorCode) obtXtqew  
{ oa:30@HSb  
System.err.println("Error Code : " + nErrorCode); ?)mM]2%%  
} ?n9?`8a#  
:}3;z'2]l  
[RFF&uy  
//停止文件下载 x$;kA}gy  
public void siteStop() g4NbzU[I  
{ $i.)1.x  
bStop = true; jyFXAs2  
for(int i=0;i<nStartPos.length;i++) /qObXI  
fileSplitterFetch.splitterStop(); 1jkMje  
.vk|aIG  
az;o7[rI^  
} =.yKl*WV{  
} %2z] 2@  
//负责部分文件的抓取 `AcT}. u  
**FileSplitterFetch.java W=ar&O~}n  
*/ ;=F]{w]$+  
package NetFox; AD4Ot5  
*Rj(~Q/t  
!/wR[`s9w  
import java.io.*; 7FvtWE*  
import java.net.*; ar[*!:!  
=6^phZ(  
tZqy \_G  
public class FileSplitterFetch extends Thread { fLR\@f  
a534@U4,  
f]37Xl%I  
String sURL; //File URL ^Uq"hT(41  
long nStartPos; //File Snippet Start Position 18];fC  
long nEndPos; //File Snippet End Position EH~XN9b  
int nThreadID; //Thread's ID HL34pmc  
boolean bDownOver = false; //Downing is over CH4 ~9mmE  
boolean bStop = false; //Stop identical $pGdGV\H  
FileAccessI fileAccessI = null; //File Access interface o<\9OQ0  
gy6Pf4Yo  
1GI/gc\  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  k.("<)  
{ *9I/h~I  
this.sURL = sURL; fsH =2p  
this.nStartPos = nStart; z-;2)RkV2  
this.nEndPos = nEnd; kCVA~ %d7  
nThreadID = id; <yz&> +9,  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 +c-?1j  
} CF_pIfbaf  
4;.y>~z  
iQJ[?l`  
public void run() 0tyS=X;#e  
{ OD`?BM  
while(nStartPos < nEndPos && !bStop) )%D>U  
{ wR*>9LjeG  
6im!v<1Qx  
^oT!%"\  
try{ o:8*WCiqrN  
URL url = new URL(sURL); ZQ'bB5I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .uwD;j +#  
httpConnection.setRequestProperty("User-Agent","NetFox"); !i77v, (#|  
String sProperty = "bytes="+nStartPos+"-"; +8~C&K:  
httpConnection.setRequestProperty("RANGE",sProperty); sm>5n_Vw  
Utility.log(sProperty); Vi o ~2  
[mJmT->  
`am]&0g^+(  
InputStream input = httpConnection.getInputStream(); ubZcpqm?Q  
//logResponseHead(httpConnection); /2#1Oi)o  
*D6X&Hg&5  
rj> _L  
byte[] b = new byte[1024]; 8O_0x)X  
int nRead; 5y%-K=d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Hd9vS"TN]  
{ 8,m3]Lg  
nStartPos += fileAccessI.write(b,0,nRead); %}0B7_6B+@  
//if(nThreadID == 1) JLFZy\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qTD^Vz V  
} Kfl#78$d  
Z<^TO1xs9B  
z-X_O32  
Utility.log("Thread " + nThreadID + " is over!"); e ) ?~  
bDownOver = true; q|_t=YM@  
//nPos = fileAccessI.write (b,0,nRead);  ]H_|E  
} TEYn^/n~  
catch(Exception e){e.printStackTrace ();} H 6~6hg  
} |NoTwK  
} gvl3NQQ%t  
r#;GVJR6  
Obb"#W@3  
//打印回应的头信息 do>,ELS+m  
public void logResponseHead(HttpURLConnection con) L/sMAB  
{ p ! _\a  
for(int i=1;;i++) &)y$XsSMW  
{ 4UV<Q*B\F  
String header=con.getHeaderFieldKey(i); )%T< Mw2u  
if(header!=null) M7JQw/,xs  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); KqNbIw*sR  
Utility.log(header+" : "+con.getHeaderField(header)); Sh+$w=vC  
else ;"N4Yflz  
break; DbH"e  
} LqA&@  
} \)' o{l&  
+dgHl_,i  
W-UMX',0zS  
public void splitterStop() 0/@ ^He8l  
{ IVblS iFF  
bStop = true; -4IHs=`;I  
} /suW{8A(E  
2S^:fm}  
rrL gBeQa  
} Un[ 0or  
U:1cbD7|3  
Gi=s|vt  
/* t6JM%  
**FileAccess.java $ /p/9 -  
*//文件访问(定位,写) k~,({T<  
package NetFox; ! O~:  
import java.io.*; 2/ES.>K!.  
 <RaM@E  
UG5AF Z\  
public class FileAccessI implements Serializable{ ;p_@%*JAx  
QO&{Jx.^[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _hz}I>G@B  
RandomAccessFile oSavedFile; V ~%C me  
long nPos; a#L:L8T;j  
5zf bI  
4 [K"e{W3  
public FileAccessI() throws IOException o,D7$WzL  
{ <jwQ&fm)/R  
this("",0); "7X[@xX@  
} {k"t`uo_  
9>I&Z8J$M  
(O@fgBM  
public FileAccessI(String sName,long nPos) throws IOException uZ/XI {/  
{ g;n6hXq4  
oSavedFile = new RandomAccessFile(sName,"rw"); kQt#^pO)  
this.nPos = nPos; ><Awk~KR  
oSavedFile.seek(nPos); r|,_qNrw  
} dvX[,*wz  
q@(MD3OE  
mN&B|KWU  
public synchronized int write(byte[] b,int nStart,int nLen) K275{ydN  
{ %p t^?  
int n = -1; w28&qNha  
try{ Dm+[cA"I  
oSavedFile.write(b,nStart,nLen); *&nIxb60b{  
n = nLen; BJNZH#"  
} J\%SAit@  
catch(IOException e) :I !}ZD+Z  
{ [0M`uf/u  
e.printStackTrace (); oH ] _2[ !  
} L#6!W  
^1mnw@04  
N}\%r&KR=  
return n; .X](B~\!  
} Qt+i0xd  
b2 5.CGF  
\Aq$h:<  
} Zb4+zps^-  
m<liPl uv  
L4t( Y7  
/* ?;xL]~Q~1  
**SiteInfoBean.java epm ~  
*/ WZ6'"Cz`  
package NetFox; kuI$VC  
#i'wDvhol  
vKFEA7  
public class SiteInfoBean { [fZhfZ)<  
;#XF.l,u  
<To$Hb,NP  
private String sSiteURL; //Site's URL F6Ne?[b  
private String sFilePath; //Saved File's Path %)#yMMhR  
private String sFileName; //Saved File's Name >z|bQW#2  
private int nSplitter; //Count of Splited Downloading File zb,YYE1  
i[4t`v'Dk  
jb83Y>  
public SiteInfoBean() K 3.z>.F'h  
{//nSplitter的缺省值为5 k@ So l6  
//default value of nSplitter is 5 `P/87=h  
this("","","",5); ~o X`Gih  
} U)6Ew4uRxV  
\ !qe@h<  
$g&_7SJ@  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) yW]>v>l:Eg  
{ H g04pZupN  
sSiteURL= sURL; oH"VrS 6  
sFilePath = sPath; E0*62OI~O  
sFileName = sName; ecMpU8}rR  
this.nSplitter = nSpiltter; Ie7S'.Lmq  
q${+I(b,  
n3_| # 1Qu  
} 49tJ+J-N  
A)80qx:  
7TB&Q*Zf  
public String getSSiteURL() cMoBYk  
{ W_bA.z T{  
return sSiteURL; = J0r,dR  
} 2= )V"lR\  
J 7HOSFwXn  
RHu4cK!5  
public void setSSiteURL(String value) eHc.#OA&  
{ Im"8+756  
sSiteURL = value; Fgw$;W  
} 5 D[`nU}  
q-r5zGI  
=6d'/D#J  
public String getSFilePath() /}Ct2w&<k  
{ Q;k D Jo  
return sFilePath; @g] >D  
} S76x EL  
l<UA0*t  
4bq+(CI6  
public void setSFilePath(String value) \F9HsR6  
{ [H=l# W@  
sFilePath = value; <Q@{6  
} ?8ady% .ls  
H8A=]Gq  
h3(B7n7  
public String getSFileName() us )NgG  
{ $AF,4Ir-b+  
return sFileName; FPkig`(3  
} `{&l _  
I#- T/1N  
~)#xOE}  
public void setSFileName(String value) yHnN7&  
{ 0Ci:w|J  
sFileName = value; =zRjb>  
} f!bGH-.r5  
mMtva}=*  
6.M!WK{+  
public int getNSplitter() ch)#NHZ9F  
{ DcsQ6  
return nSplitter; ',s{N9  
} 6)1xjE#  
tg;AF<VI  
q) !G5j3  
public void setNSplitter(int nCount) ;5:3 =F>ao  
{ ksV ^Y=]  
nSplitter = nCount; t]6 4=  
} )%bY2 pk  
} U(\ ^!S1  
l-q.VY2  
/ jN &VpDG  
/* zJTSg  
**Utility.java Dw&_6\F@  
*/ t Z]b0T(e  
package NetFox; ,%]x T>kH  
fH 0&Wc3yC  
WZf}1.Mh*  
public class Utility { |$`I1  
| (: PX  
,S7M4ajVZB  
public Utility() aq$adPtu  
{ ^fhkWx4i  
.] BJM?9  
LLJsBHi-  
} 9m}c2:p  
=~ ="#  
//线程睡眠 aZL FsSY  
public static void sleep(int nSecond) .!Os'Y9[,  
{ G;;iGN  
try{ 4fau 9bW  
Thread.sleep(nSecond); |r/4 ({n  
} \q:PU6q  
catch(Exception e) }tPI#[cfK  
{ F}4jm,w  
e.printStackTrace (); gg QI  
} CDGN}Q2_  
} oT[8Iu  
qW t 9Tr  
//日志 BZRC0^-C@  
public static void log(String sMsg) r&D&xsbQ  
{ Gu\lV c  
System.err.println(sMsg); QW6\~l 4  
} 6Ej@;]^^-  
xyRZ v]K1  
Z{ b($po  
public static void log(int sMsg) ?iaD;:'qE  
{ gf U!sYZ  
System.err.println(sMsg); Hh0a\%!  
} ['_G1_p  
} Hbi2amfBu  
~ H $q  
Uv(Uj3D  
/*  ^6Y:9+  
**TestMethod.java '>"-e'1m(  
*/ 5:~BGK&{Y  
package NetFox; l;'c6o0e  
c!=^C/5Ee  
&HYs^|ydrr  
public class TestMethod { L }&$5KiwV  
wEJ?Y8  
/]"2;e-s+  
public TestMethod() y w>T1  
{ ///xx/weblogic60b2_win.exe "ju0S&  
try{ R{A$hnhW6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); %SD=3UK6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); l/@t>%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Zv)x-48  
fileFetch.start(); 8Qi@z Jq,  
} x@480r  
catch(Exception e){e.printStackTrace ();} ]BBL=$*  
\ D,c*I|p7  
 d`&F  
} ,MdK "Qa>  
ET}Dh3A  
4^Ghn  
public static void main(String[] args) i-_ * 5%A  
{ _T[m YY  
new TestMethod(); ( mKuFz7  
} 7!-y72qx  
} 0s8w)%4$  
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