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http断点续传简单实现(java)

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/* 5~8FZ-x  
**SiteFileFetch.java Qk`ykTS!  
*/ iB-h3/  
package NetFox; <;eXbO>Q  
import java.io.*; ;&iZ {  
import java.net.*; .0ov>4,R  
Ei$?]~ &  
+`jI z'+  
public class SiteFileFetch extends Thread { Q5K<ECoPk  
/xS4>@hn  
t?&@bs5~g  
SiteInfoBean siteInfoBean = null; //文件信息Bean Xgb ~ED]  
long[] nStartPos; //开始位置 sWtT"7>x  
long[] nEndPos; //结束位置 7tZvz `\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1VXyn\  
long nFileLength; //文件长度 $!Qv f  
boolean bFirst = true; //是否第一次取文件 WF#3'"I  
boolean bStop = false; //停止标志 mE>v (JY  
File tmpFile; //文件下载的临时信息 >{ /As][  
DataOutputStream output; //输出到文件的输出流 6I8A[   
,q_'l?Pn  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) p-CBsm5P  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1UHlA8w7 Q  
{ A5WchS'  
siteInfoBean = bean; &Y `V A  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); H]I^?+)9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); n7EG%q6m+  
if(tmpFile.exists ()) PJ$C$G  
{ !\'NBq,  
bFirst = false; KCDbE6  
read_nPos(); ='rSB.$Ctk  
} 7A,QA5G ]C  
else >0XB7sC  
{ U-]Rm}X\M  
nStartPos = new long[bean.getNSplitter()]; =P}BAJ  
nEndPos = new long[bean.getNSplitter()]; n PAl8  
} !k5I#w:  
DA9-F  
UgqfO(  
QXaE2}}P  
} 3)ZdT{ MY  
= n>aJ(=Pd  
N'5AU (  
public void run() @gc|Z]CV  
{ G d%X> ~  
//获得文件长度 MJyz0.9c  
//分割文件 {?+dVLa^;  
//实例FileSplitterFetch - WEEnwZ  
//启动FileSplitterFetch线程 Q`0 k=<  
//等待子线程返回 wO-](3A-8P  
try{ .sqX>sU/]  
if(bFirst) 7>@g)%",  
{ -O~ V4004  
nFileLength = getFileSize(); 9y$"[d27;+  
if(nFileLength == -1) AcoU.tpP  
{ iHYvH   
System.err.println("File Length is not known!"); |Q|vCWel{  
} h=x{ 3P;B  
else if(nFileLength == -2) ;:`0:Ao.  
{ 4tGP- L  
System.err.println("File is not access!"); 6he (v  
} G+k~k/D6  
else fR^aFT  
{ :nLhg$wMs  
for(int i=0;i<nStartPos.length;i++) s{Wj&.)M  
{ 1woBw>g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); }Ghh%]  
} 9im<J'  
for(int i=0;i<nEndPos.length-1;i++) /c4@QbB  
{ 5H{dLZ],  
nEndPos = nStartPos[i+1]; XX9u%BZ~  
} _+0Q Q{'N  
nEndPos[nEndPos.length-1] = nFileLength; kv8 /UW  
} jI%g!  
} Q($.s=&l;  
Vi:<W0:  
)a;ou>u  
//启动子线程 KD(}-zUs  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; sM  _m  
for(int i=0;i<nStartPos.length;i++) CS\ E]f  
{ #q-7#pp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A}h`%b  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), h ycdk1SN  
nStartPos,nEndPos,i); :enmMB#%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ? CabVj-r  
fileSplitterFetch.start(); OZCbMeB{+J  
} IPTEOA<M[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), q\I2lZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 9FKowF_8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", PKK18E}{%^  
nEndPos = " + nFileLength); jn:9Cr,o;g  
// fileSplitterFetch[nPos.length-1].start(); qiyX{J7Z  
OtsW>L@ O(  
"'9[c"Iz  
//等待子线程结束 dU<qFxW  
//int count = 0; i| /EA7  
//是否结束while循环 Z{p)rscX  
boolean breakWhile = false; vi8)U]6  
F?jFFw im  
QVq+';cG  
while(!bStop) /t $J<bU  
{ }z|@X KA#  
write_nPos(); 49Y_ze6L}  
Utility.sleep(500); 0D Q\akh  
breakWhile = true; PSR21;  
B{dR/q3;@  
fEgwQ-]  
for(int i=0;i<nStartPos.length;i++) c:OFBVZ   
{ cZFG~n/  
if(!fileSplitterFetch.bDownOver) 6$*\%  
{ = VFPZ  
breakWhile = false; O&vE 5%x  
break; gd=gc<zYP  
} '^# =,+ A  
} V!XT=Ou?6  
if(breakWhile) fa:V8xa  
break; qHtonJc  
x<lY&KQ0  
))xyaYIZkk  
//count++; lij>u  
//if(count>4) 6|HxBC#4  
// siteStop(); 5p]Cwj<u  
} W_\~CntyZ  
M7x*LiKc2  
N#!**Q 0  
System.err.println("文件下载结束!"); ZaKT~f%%z  
} /ZpwJc`e  
catch(Exception e){e.printStackTrace ();} ) Z^b)KAk  
} 8gK  <xp  
dF#`_!4pbf  
BJ,D1E  
//获得文件长度 grWmF3c#  
public long getFileSize() w /l\p3n  
{ xJemc3]2  
int nFileLength = -1; O3];1ud  
try{ >dU.ic?19  
URL url = new URL(siteInfoBean.getSSiteURL()); z<h?WsL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O S%  
httpConnection.setRequestProperty("User-Agent","NetFox"); {!]7=K)W9  
R8(Bt73  
J 6%CF2  
int responseCode=httpConnection.getResponseCode(); Dmq_jt  
if(responseCode>=400) !YZ$WiPl  
{ WNo",Vc  
processErrorCode(responseCode); 6{8dv9tK  
return -2; //-2 represent access is error %X^K5Io  
} .r4M]1Of  
5k]xi)%  
QH]G>+LI5  
String sHeader; wSGW_{;-  
W, YYL(L  
%'`L+y  
for(int i=1;;i++) A."]6R<  
{ YZllfw$9  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K H&o`U(}  
//Utility.log(in.readLine()); R'e>YDC  
sHeader=httpConnection.getHeaderFieldKey(i); "gQA|NHwV  
if(sHeader!=null) +`_Km5=  
{ 8F(Vd99I  
if(sHeader.equals("Content-Length"))  >M-ZjT>  
{ T:?01?m  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); FM=- ^l,  
break; }(-2a*Z;Y  
} |(Q !$  
} A!bH0=<I  
else &E+2  
break; ?K>=>bS^h  
} 'v?"TZ  
} IJzPWs5W:  
catch(IOException e){e.printStackTrace ();} 1O@y >cV  
catch(Exception e){e.printStackTrace ();} ;:l>Kac  
}g]O_fN7~  
wB0K e  
Utility.log(nFileLength); >/eV4ma"  
q?TI(J+/  
K2gg"#ft?  
return nFileLength; 4Y!_tZ>  
} 66jL2XU<  
HgfeSH  
"(cMCBVYdA  
//保存下载信息(文件指针位置) E3`&W8  
private void write_nPos() z($h7TZ$  
{ )(`HEl>-9c  
try{ Pko2fJt1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); J*}Qnl+  
output.writeInt(nStartPos.length); azT@S=,  
for(int i=0;i<nStartPos.length;i++) Q/u1$&1  
{ Bq 9 Eu1  
// output.writeLong(nPos); m:4Ec>?e  
output.writeLong(fileSplitterFetch.nStartPos); E6njm du  
output.writeLong(fileSplitterFetch.nEndPos); $Il:Yw_  
} ek9Y9eJ"  
output.close(); uL1$yf'  
} ![}q9aeT  
catch(IOException e){e.printStackTrace ();} }_GI%+t  
catch(Exception e){e.printStackTrace ();} < X&{6xu  
} } 0^wJs  
Z<M?_<3  
jJU9~5i?  
//读取保存的下载信息(文件指针位置) l$mfsm|{:  
private void read_nPos() SIr^\iiOB  
{ ^Ox|q_E w}  
try{ +\@}IKWl-?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); w]Byl3}Gt  
int nCount = input.readInt(); U) B^R  
nStartPos = new long[nCount]; a-(OAzQ_  
nEndPos = new long[nCount]; E>2~cC*  
for(int i=0;i<nStartPos.length;i++) hnD=DLW $  
{ cZd{K[fuK  
nStartPos = input.readLong(); /ltGSl  
nEndPos = input.readLong(); G j9WUv[P  
} N sNk  
input.close(); v$_YZm{!<  
} | bWvQdN  
catch(IOException e){e.printStackTrace ();} `zmj iC  
catch(Exception e){e.printStackTrace ();} RV{'[8gM   
} -Uu65m~:{k  
!GL kAV  
fH6mv0  
private void processErrorCode(int nErrorCode) WY3D.z-</  
{ yWkg4  
System.err.println("Error Code : " + nErrorCode); mO|YX/>  
} lf?dTPrD  
OqNtTk+  
//W7$DYEG  
//停止文件下载 1GA$nFBVC  
public void siteStop() 8n`O{8:fi  
{ Bk)*Z/1<x  
bStop = true; [<H'JsJl  
for(int i=0;i<nStartPos.length;i++) |^!  
fileSplitterFetch.splitterStop(); y)%CNH)*x  
AFN"#M  
<1xs ya[e  
} u hJnDo  
} 5q Y+^jO]o  
//负责部分文件的抓取 ^_C]?D?  
**FileSplitterFetch.java IA&NMf;{  
*/ ,y%4QvG7a  
package NetFox; :K]&rGi,  
N~] 4,~  
R3,O;9i  
import java.io.*; dnXre*rhz  
import java.net.*; wx2 EMr   
I C?bqC+  
$-Wn|w+h<a  
public class FileSplitterFetch extends Thread { {~u#.(  
m?4L>'  
THcK,`lX@  
String sURL; //File URL sH_5.+,`  
long nStartPos; //File Snippet Start Position Z&w/JP?  
long nEndPos; //File Snippet End Position |MEu"pY)  
int nThreadID; //Thread's ID g E#4 3  
boolean bDownOver = false; //Downing is over Sh(Ws2b7  
boolean bStop = false; //Stop identical n +R3  
FileAccessI fileAccessI = null; //File Access interface P g{/tM Y  
5:r*em  
A\IQM^i  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g$P<`.  
{ <!m'xOD  
this.sURL = sURL; %40uw3  
this.nStartPos = nStart; BZr$x8%ki  
this.nEndPos = nEnd; Q(gc(bJV  
nThreadID = id; k.MAX8  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 MfJ8+3@K  
} npD`9ff  
&R7N^*He  
+&j&es  
public void run() [h;&r"1  
{ ML9nfB^z!  
while(nStartPos < nEndPos && !bStop) 8:QnxrODP  
{ F4T}HY>nZ  
w4UaWT1J  
U|2*.''+Q  
try{ %; 0l1X  
URL url = new URL(sURL); U.mVz,k3  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Za4X ;  
httpConnection.setRequestProperty("User-Agent","NetFox"); w!8xZu  
String sProperty = "bytes="+nStartPos+"-"; FK~FC:K  
httpConnection.setRequestProperty("RANGE",sProperty); p#fd+  
Utility.log(sProperty); Kx[u9MD  
93+p~?  
gs?=yNL  
InputStream input = httpConnection.getInputStream(); eq<giHJM  
//logResponseHead(httpConnection); P}dhpU  
vsDR@Y}k  
h0v4!`PQ-  
byte[] b = new byte[1024]; XC NM  
int nRead; ]z{f)`;I  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ImnN&[Cu  
{ IC[iCrB  
nStartPos += fileAccessI.write(b,0,nRead); {y0`p1  
//if(nThreadID == 1) s1/:Ts[3i  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); t^Hte^#S  
} _Vj uQ  
Ait3KIJ9  
2wKW17wj,  
Utility.log("Thread " + nThreadID + " is over!"); =Y;w O8  
bDownOver = true; &F xw19[G  
//nPos = fileAccessI.write (b,0,nRead); 'c")]{  
} iR`c/  
catch(Exception e){e.printStackTrace ();} e.<y-b?  
} p"lTZ7c:Y  
} $: %U`46%s  
vi :IO  
Ev'Bm Dk  
//打印回应的头信息 ,cg%t9  
public void logResponseHead(HttpURLConnection con) fsr0E=nV  
{ dDeImSeV  
for(int i=1;;i++) M:*^k  
{ ;K+'J0  
String header=con.getHeaderFieldKey(i); 4PVkKP'/  
if(header!=null) vxmz3ht,Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); OB&lq.r  
Utility.log(header+" : "+con.getHeaderField(header)); \4B2%H  
else /'S@iq  
break; n,.ZLuBEX  
} &q?A)R  
} liuF;*  
EP ;TfWc}1  
"N|gU;~W  
public void splitterStop() $2?10}mrx  
{ \@ j YY~  
bStop = true; $u`v k|\R  
} 4z$}e-  
yhBf%m  
YH%aPsi  
} T9,T'y>BD  
oK!W<#  
@fML.AT  
/* -5_[m@Vr  
**FileAccess.java |KM<\v(A{  
*//文件访问(定位,写) p? q~.YY  
package NetFox; R>05MhA+  
import java.io.*; qit D{;  
2d`:lk%\  
XKTX~:  
public class FileAccessI implements Serializable{ 0i4 X,oHjG  
?'I[[KuG  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 i5QG_^X&  
RandomAccessFile oSavedFile; gp/_# QVWC  
long nPos; Ki"o0u  
$xWebz0  
:())%Xu3  
public FileAccessI() throws IOException qg(rG5kD@  
{ h)vRvfcmY  
this("",0); /61P`1y(J  
} D{4Ehr "T  
xK3 xiR  
0."TSe83\  
public FileAccessI(String sName,long nPos) throws IOException w,'"2^Cwy  
{ Fa!6*K\  
oSavedFile = new RandomAccessFile(sName,"rw"); cnrS.s=  
this.nPos = nPos; `k>h2(@9S  
oSavedFile.seek(nPos); f8m%T%]f  
} `(RQh@H  
RH=Tu6i  
BgzER[g|q{  
public synchronized int write(byte[] b,int nStart,int nLen) v@6TC1M,  
{ %dyEF8)  
int n = -1; @y#QHJ.j  
try{  ?Cu1"bl  
oSavedFile.write(b,nStart,nLen); Hvm+Tr2@  
n = nLen; JpFfO<uO  
} :-I~-Yj  
catch(IOException e) vWM3JH~a6  
{ RuW62QSq  
e.printStackTrace (); h7EKb-@  
} D9#?l <D  
r dc} e"v  
Q|^TR__  
return n; q $Hg\ {c  
} j70]2NgX  
ZW]Q|vPh4U  
7,\Uk|  
} sw(dd01a 7  
:[#~,TW  
}P5zf$  
/* _>G=v!  
**SiteInfoBean.java w_gPX0N}3n  
*/ !_EaF`oh(  
package NetFox; i&r56m<  
3E!#?N|v  
XYKWOrkQqa  
public class SiteInfoBean { X>n\@rTo  
1-Fz#v7p  
Whf7J'  
private String sSiteURL; //Site's URL GS%i<HQ3  
private String sFilePath; //Saved File's Path ,@_$acm  
private String sFileName; //Saved File's Name L=. 4x=%%  
private int nSplitter; //Count of Splited Downloading File ?a h<Qf]  
=ZsM[wd  
MZ(TST"  
public SiteInfoBean() @aG1PG{  
{//nSplitter的缺省值为5 g[rxK n\Z  
//default value of nSplitter is 5 'wo[iNy[  
this("","","",5); b9ON[qOMN  
} kp4*|$]  
Jl"),;Od  
blwdcdh  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) > n~l\ fC  
{ e7{n=M  
sSiteURL= sURL; =sqh PS<>  
sFilePath = sPath; iK*2 Z$`lw  
sFileName = sName; v;E7UL .w  
this.nSplitter = nSpiltter; 6\MJvg\;  
3~e"CKD>  
G;n'c7BV  
} `ym@ U(;N  
H!F Cerg  
N0@&eX|$i4  
public String getSSiteURL() 4T-9F  
{ >H@ zP8  
return sSiteURL; %!r>]M <  
} #?xhfSgr  
RLypWjMx$  
FuOP+r!H  
public void setSSiteURL(String value) KzQ\A!qG  
{ _YXk ,ME!Q  
sSiteURL = value; ?|8QL9Q"|  
} dOm#NSJVd  
f`5e0;zm  
vG(Gs=.U  
public String getSFilePath() iOB]72dh  
{ }+[H~8)5  
return sFilePath; y.AF90Q>)  
} ZQT14.$L  
m6a q_u{W  
+\FTR  
public void setSFilePath(String value) 5!ll #/ {`  
{ /B$"fxFf  
sFilePath = value; D6iHkDTg  
} ti:qOSIDTA  
7$(>Z^ Em  
:X>%6Xj?RV  
public String getSFileName() Zho d%n3  
{ mPNT*pAO  
return sFileName; f>)k<-<yj  
} <RmI)g>'_^  
%]JSDb=C  
u>Z0ug6x  
public void setSFileName(String value) `.f<RVk-  
{ 3~"G(UP  
sFileName = value; fF208A7U I  
} .:tAZZ  
h+k:G9;sS  
tT}*%A  
public int getNSplitter() AL/q6PWi  
{ \UI7H1XDH  
return nSplitter; =T)4Oziks  
} }/ 6Q3B  
]HP aM  
1FU(j*~:  
public void setNSplitter(int nCount) 0>Y3>vwSl  
{ 7Op6> i  
nSplitter = nCount; uBLI!N-G  
} nB?$W4  
} 7:U^Ki  
4,m aA  
<4z |"(  
/* B$aA=+<S  
**Utility.java :E/]Bjq$;  
*/ {n8mE,;M  
package NetFox; $m`?x5rL8  
O/^7TBTn<r  
75~>[JM  
public class Utility { ffK A  
x^kV;^ I  
:ND5po#(  
public Utility() *TY?*H  
{ ANEW^\  
T:aYv;#0  
c&.>SR')  
} V`Z-m-V~1  
*.wX9g9\  
//线程睡眠 ahNpHTPa  
public static void sleep(int nSecond) B1>aR 7dsf  
{ &wsxH4  
try{ Q=lQy  
Thread.sleep(nSecond); q]3bGO;  
} ^9zL[R  
catch(Exception e)  V3WHp'1  
{ +]-~UsM  
e.printStackTrace (); ^ZX71-  
} H: Rd4dl,  
} [mKPOg-t  
1.YDIB||  
//日志 VfOm#Ue0 q  
public static void log(String sMsg) E(Tvj\9  
{ JQQP!]%}  
System.err.println(sMsg); ~=~|@K  
} Sw<@u+Z;%  
ftB-gItV  
gT$`a  
public static void log(int sMsg) F@Qzh  
{ RnV )*  
System.err.println(sMsg); E7-il;`cKn  
} g$<Sh.4A  
} Md_S};!QN6  
MG<kvx~2  
bcFG$},k  
/* e[f}Lxln  
**TestMethod.java Y.&nxT95=  
*/ >[;+QVr;  
package NetFox; @l:\0cO  
 L5/J  
LY b@0O<w  
public class TestMethod { 6qQdTp{i  
[+EmV>Y  
n46H7e(ej\  
public TestMethod() H^{Eh  
{ ///xx/weblogic60b2_win.exe ?|LR@M!S7  
try{ {fe[$KQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); <eP`Lu"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 9fr LYJz"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !t/I j~o  
fileFetch.start(); f QSP]?  
} R{"Kh2q_  
catch(Exception e){e.printStackTrace ();} Mz,G;x}  
&@CcH_d*  
(27bNKr  
} v7x %V%K  
k^ B<t'  
D+G?:m R  
public static void main(String[] args) $'# hCs  
{ OKs1irt5  
new TestMethod(); *;7~aM  
} ^]}+ s(  
} *#p}>\Y{  
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