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http断点续传简单实现(java)

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/* Eh@T W%9*  
**SiteFileFetch.java h@,e`Z  
*/ B+e_Y\B u  
package NetFox; tkN3BQ  
import java.io.*; NC.P 2^%  
import java.net.*; QYTTP6 Gz+  
-)O kG#J@  
B.mbKntK)R  
public class SiteFileFetch extends Thread { aDl, K;GL  
g{W6a2  
blfE9Oy  
SiteInfoBean siteInfoBean = null; //文件信息Bean {p e7]P?  
long[] nStartPos; //开始位置 HCx%_9xlm  
long[] nEndPos; //结束位置 'ztL3(|X6  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Vo 6y8@\  
long nFileLength; //文件长度 QI#*5zm  
boolean bFirst = true; //是否第一次取文件 |pH* CCA  
boolean bStop = false; //停止标志 { 0%TMiVf  
File tmpFile; //文件下载的临时信息 ~0F9x9V  
DataOutputStream output; //输出到文件的输出流 :#\B {)(  
(' Ko#3b  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `$V[;ld(mz  
public SiteFileFetch(SiteInfoBean bean) throws IOException du'}+rC  
{ CaYos;Pl  
siteInfoBean = bean; ]]uzl0LH  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); bwSRJFqb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5hJYy`h~  
if(tmpFile.exists ()) @4_rxu&  
{ yC'hwoQ`  
bFirst = false; V%BJNJ  
read_nPos(); 5fegWCJ  
} -4vHK!l  
else YBtq0c  
{ "y~muE:.  
nStartPos = new long[bean.getNSplitter()]; "$W|/vD+  
nEndPos = new long[bean.getNSplitter()]; q: TT4MUj<  
} O2q=gYX>\  
\]U<hub  
hC|5e|S  
[%7;f|p?  
} NMl ?Y uEv  
m@G<ZCMZ  
FDVI>HK @  
public void run() E/~"j  
{ !dyxE'T2  
//获得文件长度 pkXfsi-Nu  
//分割文件 #hgmUa  
//实例FileSplitterFetch =!?[]>Dh  
//启动FileSplitterFetch线程 < QDr,Hj  
//等待子线程返回 \!UF|mD^tG  
try{ jr, &=C(  
if(bFirst) DJViy  
{ "ep`  
nFileLength = getFileSize(); ASKAgU"h  
if(nFileLength == -1) X,WQ'|rC  
{ <JL\?)}n  
System.err.println("File Length is not known!"); s- ,=e  
} `Di ^6UK(  
else if(nFileLength == -2) fiE>H~  
{ G2CZwm{/f  
System.err.println("File is not access!"); ka5#<J7<p  
} }uF[Ra  
else ?W[J[cb  
{ Qp kKVLi  
for(int i=0;i<nStartPos.length;i++) R`@8.]cpPy  
{ q+A<g(Xu  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); i?GfY C2q  
} a^*cZ?Ta  
for(int i=0;i<nEndPos.length-1;i++) <XQN;{xSa  
{ AI1@-  
nEndPos = nStartPos[i+1]; :DtZ8$I`]C  
} UF&0 & `@  
nEndPos[nEndPos.length-1] = nFileLength; Vs_\ykO  
} r6d0x  
} k4qLB1&,  
z5XYpi_;[  
_M8G3QOx  
//启动子线程 :3KO6/+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; IajD;V  
for(int i=0;i<nStartPos.length;i++) (KT38RhA  
{ 1MbY7!?PG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R'Kt=.s<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &mN'Tk  
nStartPos,nEndPos,i); pU?{0xZH  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 81GQijq  
fileSplitterFetch.start(); >_;kTy,  
} 6 gj]y^}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )KSisEL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :/o C:z\h  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", { 1+Cw?1d  
nEndPos = " + nFileLength); A",eS6  
// fileSplitterFetch[nPos.length-1].start(); ]b4pI*:$I  
Ik`O.Q.}  
F(Lb8\to\M  
//等待子线程结束 5;IT64&]  
//int count = 0; _PK}rr?"7O  
//是否结束while循环 $Y8>_6%+T  
boolean breakWhile = false; 99<4t$KH  
E% <w5d.lq  
v<L=!-b^  
while(!bStop) nd.57@*M  
{ J.1O/Pw!.a  
write_nPos(); P@qMJ}<j  
Utility.sleep(500); 7~_{.f  
breakWhile = true; Yo>`h2C4  
x&at^Fp  
).pO2lLF4  
for(int i=0;i<nStartPos.length;i++) /8f>':zUb  
{ an3~'g?  
if(!fileSplitterFetch.bDownOver) h/,R{A2mO  
{ u@<Pu@?xm  
breakWhile = false; :lUX5j3  
break; K@B" ]6  
} 8O,? |c=>  
} P+[QI U  
if(breakWhile) 30D: ZmlY  
break; qs=Gj?GwGQ  
lc]V\ 'e  
?#d6i$  
//count++; =v.{JV#  
//if(count>4) kW#S]fsfU  
// siteStop(); q[-|ZA bbr  
} n'T He|:I  
N? M   
1o8wy_eSs  
System.err.println("文件下载结束!"); 0s1'pA'  
} G3G/ xC"  
catch(Exception e){e.printStackTrace ();} $30oc Tt{  
} W7t >&3l  
|~z3U>  
Odm#wL~E  
//获得文件长度 IE2CRBfs  
public long getFileSize() YQ; cJ$  
{ N1%p"(  
int nFileLength = -1; f0vJm  
try{ T'E ] i!$  
URL url = new URL(siteInfoBean.getSSiteURL()); u^Vh .g]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <0#^7Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); YydA6IK4  
j.DHqHx  
Bz?l{4".  
int responseCode=httpConnection.getResponseCode(); xq2V0Jp1u  
if(responseCode>=400) X/l;s  
{ _3/ec]1  
processErrorCode(responseCode); 5y]io Jc9-  
return -2; //-2 represent access is error %Uy%kN_&  
} 'TL2%T/)t  
jo}1u_OJ  
ygN>"eP  
String sHeader; [& ^RP,N~  
} ~| k  
8'_ 0g[s  
for(int i=1;;i++) @xS]!1-  
{ i\)3l%AK]T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); gw^'{b  
//Utility.log(in.readLine()); fxd0e;NAAh  
sHeader=httpConnection.getHeaderFieldKey(i); kx:jI^  
if(sHeader!=null) f8=]oa]  
{ 'f+NW &   
if(sHeader.equals("Content-Length")) pLnB)z?  
{ !;v.>.lw  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); dQD$K|aUp  
break; <*<U!J-i  
} h d2'AlB  
} aE)by-'  
else :_xh(W+2<  
break; y(5:}x&E  
} /1d<P! H  
} [}-3PpF  
catch(IOException e){e.printStackTrace ();} CE ~@}`  
catch(Exception e){e.printStackTrace ();} W\8Ln>  
l+zb~  
~}'F887f  
Utility.log(nFileLength); x GH1epf  
Y/fJQ6DY  
P|xG\3@Z  
return nFileLength; gmP9j)V6  
} dU_;2#3m  
2'|8Q\,:4Z  
0fArF*  
//保存下载信息(文件指针位置) N|K4{Frm  
private void write_nPos() y 9L14  
{ ^zr^ N?a  
try{ jVWK0Zba  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^U@~+dw  
output.writeInt(nStartPos.length); !yJICjXj  
for(int i=0;i<nStartPos.length;i++) QJGKQ2^ n  
{ ?X9U TOx  
// output.writeLong(nPos); W0I4Vvh_"  
output.writeLong(fileSplitterFetch.nStartPos); YcDe@Zuwn  
output.writeLong(fileSplitterFetch.nEndPos); *[}^[J x  
} =(o']ZaaA  
output.close(); 5,)vJ,fs  
} nZk +  
catch(IOException e){e.printStackTrace ();} 4aUiXyr*2  
catch(Exception e){e.printStackTrace ();} = QO g 6  
} %*}Y6tl'|  
"ju'UOcS/  
iE].&>w  
//读取保存的下载信息(文件指针位置) F@YKFk+a  
private void read_nPos() 646JDX[o  
{ g)"gw+ZFc  
try{ sG7u}r  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); eWs&J24  
int nCount = input.readInt(); m Y,|J\w@  
nStartPos = new long[nCount]; K.~q+IYP[  
nEndPos = new long[nCount]; 3Q^fVn$tk  
for(int i=0;i<nStartPos.length;i++) E_T 2z4lw  
{ L2UsqVU  
nStartPos = input.readLong(); 1q7tiMvV-  
nEndPos = input.readLong(); ino:N5&;;  
} xc @Ss[  
input.close(); j<<3Pr  
} `G9 l  
catch(IOException e){e.printStackTrace ();} 5GzFoy)j>  
catch(Exception e){e.printStackTrace ();} 3FE(}G  
} soRv1)el  
zp}eLm:=d  
}H> ^o9  
private void processErrorCode(int nErrorCode) [iP#VM-N  
{ IxZb$h[  
System.err.println("Error Code : " + nErrorCode); (V:E2WR  
} X{xBYZv4  
)!:sFa 1  
w>; L{  
//停止文件下载 ] }|byo  
public void siteStop() e'%v1-&sP  
{ *cuuzi&  
bStop = true; V~G`kkNy  
for(int i=0;i<nStartPos.length;i++) k <iTjI*N  
fileSplitterFetch.splitterStop(); ElhRF{R  
@gC=$A#  
Fb`a~c~s  
} a' Ki;]q  
} `{k"8#4:qA  
//负责部分文件的抓取 %ts^Z*3u  
**FileSplitterFetch.java \MC-4Yz  
*/ JxE53ev  
package NetFox; ~c^>54  
e}/Lk5q!  
V&8Vw F^-  
import java.io.*; klg25#t  
import java.net.*; gxz-R?.  
m7a#qs; ,  
hI%bjuq  
public class FileSplitterFetch extends Thread { ryF7  
f"7O  "6  
3~S'LxV  
String sURL; //File URL IN8>ZV`j)  
long nStartPos; //File Snippet Start Position 00v&lQBW  
long nEndPos; //File Snippet End Position ]^':Bmq  
int nThreadID; //Thread's ID F'jWV5"*  
boolean bDownOver = false; //Downing is over ]H-S, lmV  
boolean bStop = false; //Stop identical %~L>1ShtU  
FileAccessI fileAccessI = null; //File Access interface $vC1 K5sLk  
MFTk qbc  
J;_}lF9d@  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException X[`bMa7IB(  
{ k.("3R6v:  
this.sURL = sURL; \$0F-=w`8  
this.nStartPos = nStart; `>0MNmu  
this.nEndPos = nEnd; B`*ZsS=R-  
nThreadID = id; p&+;w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 5^']+5_vb  
} *.L81er5~  
kt`nbm|aw  
/|#&px)G  
public void run() 7+X:LA~U  
{ "k]CW\H6z  
while(nStartPos < nEndPos && !bStop) d ;vT ~;  
{ O"Ku1t!  
il|1a8M2~  
~P~  
try{ | N0Z-|  
URL url = new URL(sURL); q0f3="  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^O^l(e!3  
httpConnection.setRequestProperty("User-Agent","NetFox"); lY|Jr{+Ln  
String sProperty = "bytes="+nStartPos+"-"; U2uF&6v  
httpConnection.setRequestProperty("RANGE",sProperty); }*.0N;;C  
Utility.log(sProperty); *K> l*l(f]  
=]:>"_jN  
GKN%Tv:D_  
InputStream input = httpConnection.getInputStream(); GpZ c5c  
//logResponseHead(httpConnection); I%- " |]$  
t]7&\ihZi~  
n6s}ww)  
byte[] b = new byte[1024]; n 1!?"m!  
int nRead; *OuStr \o  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Cmc3k,t  
{ foJdu+^  
nStartPos += fileAccessI.write(b,0,nRead); ,9WBTH8  
//if(nThreadID == 1) sR/b$j>i3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); O'Js}  
} W6On9 3sa  
9Xx's%U  
Cvn#=6V3  
Utility.log("Thread " + nThreadID + " is over!"); ()~pY!)1/  
bDownOver = true; 7 S?4XyU/o  
//nPos = fileAccessI.write (b,0,nRead); LpR3BP@At  
} `rf_7  
catch(Exception e){e.printStackTrace ();} +$oF]OO  
} ]\7]%(  
} J_s>N  
v|U(+O  
ZDbc  
//打印回应的头信息 rn<PR*  
public void logResponseHead(HttpURLConnection con) #1>X58I^  
{ @)Ofi j  
for(int i=1;;i++) jBegh9KHq  
{ fk_o@ G!0  
String header=con.getHeaderFieldKey(i); sQMFpIrr  
if(header!=null) DGzw8|/(  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); In`mtn q  
Utility.log(header+" : "+con.getHeaderField(header)); ]Kr `9r),  
else 4~B> 9<$e>  
break; 6R=W}q4  
} Q+YRf3$  
} OE}*2P/M>  
N^3N[lD{  
_q~=~nub  
public void splitterStop() ;[fw]P n  
{ s`0QA!G{-  
bStop = true; ki85!k=Q2  
} % LJs  
J>/w5$h5  
{GC?SaK  
} x g0iN'e'K  
?M[ A7?  
;VWAf;U;B  
/* $sEy%-  
**FileAccess.java 'Fmvu   
*//文件访问(定位,写) o<N  nV  
package NetFox; EVoE szR  
import java.io.*; TYy.jFT-  
V{JAB]?^  
j$+nKc$  
public class FileAccessI implements Serializable{ TA{\PKA)  
g1jTy7g?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~Q\3pI. |  
RandomAccessFile oSavedFile; 7D<#(CE{  
long nPos; ]MxC_V+P`  
{7)st W  
ub|V\M{  
public FileAccessI() throws IOException Y'ow  
{ '#k0a,<N  
this("",0); |`cKD >  
} zzxGAVu  
,lyb!k8  
}`@728E  
public FileAccessI(String sName,long nPos) throws IOException E2m8UBS  
{ h=:Q-?n-  
oSavedFile = new RandomAccessFile(sName,"rw"); VY3&  
this.nPos = nPos; M8tRjNWS?  
oSavedFile.seek(nPos); ;cQ6g` bM\  
} 1R,:  
l(02W  
hRCed4qA  
public synchronized int write(byte[] b,int nStart,int nLen) /Z$&pqs!  
{ >/8yGBD  
int n = -1; *NG+L)g  
try{ <WcR,d  
oSavedFile.write(b,nStart,nLen); U-|NY  
n = nLen; uXKERzg  
} Ry'= ke  
catch(IOException e) _ A=$oVe  
{ ~m$Y$,uH  
e.printStackTrace (); )gMG#>up@  
} ~P@Q7T*  
ypy68_xyW  
-:na: Vsi  
return n; PbmDNKEh{  
} S;)w.  
6Aku1h  
tQjLOv+?=  
} @~%r5pz6  
kOed ]>H  
"T|PS 6R~  
/* A -b [>} _  
**SiteInfoBean.java *m#Za<_Gv  
*/ yr lf+tl  
package NetFox; Y 1t\iU  
'hs2RSq  
@w?P7P<O`  
public class SiteInfoBean { #Jw1IcuH  
*" {lMZ +  
C<P%CG&;  
private String sSiteURL; //Site's URL 2Tagr1L  
private String sFilePath; //Saved File's Path }&[  
private String sFileName; //Saved File's Name i(NdGL#P  
private int nSplitter; //Count of Splited Downloading File fP. 6HF_p_  
zR{W?_cV  
xLC3>>P  
public SiteInfoBean() 6E^.7%3  
{//nSplitter的缺省值为5 |fHV2Y`:g  
//default value of nSplitter is 5 v+X)Qmzf~  
this("","","",5); RR]CW  
} tfGHea)M  
xjVS   
<UQe.K"  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) !Y[lQXv  
{ XR;eY:89  
sSiteURL= sURL; eb=D/  
sFilePath = sPath; #':fkIYe'  
sFileName = sName; {62n7'U{  
this.nSplitter = nSpiltter; QC9eUYe  
fP(d8xTx2y  
m+Rv+_R  
} K[!&b0O  
[_Qa9e  
`a2n:F  
public String getSSiteURL() RE/~#k@a  
{ 1fZ(l"  
return sSiteURL; u)~C;f)  
} zc;|fHW~O  
!K'}K>iT  
o !vE~  
public void setSSiteURL(String value) rv|)n>m  
{ (w}H]LQ  
sSiteURL = value; P7{gfiB  
} Uk6HQQ  
x;8A!8w  
AD|2q M))  
public String getSFilePath() ~x ]jB  
{ Yo|,]X>/  
return sFilePath; <c2'0I >  
} Z\k&gio5C^  
\Hn>oonph  
lx[oaCr  
public void setSFilePath(String value) ,"HL~2:~  
{ ;N 0~;I  
sFilePath = value; _Nqt21sL  
} /K. !sQ$  
"-+\R}q$  
4#:W.]U8  
public String getSFileName() ;{U@qQD7  
{ ]3X@_NYj  
return sFileName; y9>ZwYN  
} ~2gG(1%At9  
%3ICI  
1f":HnLRM  
public void setSFileName(String value) 3ZXQoC '  
{ hMykf4  
sFileName = value; TztAZ2C  
} /(.mp<s0  
sXD1C2o  
E.Jkf\  
public int getNSplitter() Qm Ce>+  
{ Yq%9M=#k  
return nSplitter; <gQIq{B?  
} .MP !`  
O vk_\On  
GJoS #s  
public void setNSplitter(int nCount) x7eQ2h6O  
{ c'S,hCe*  
nSplitter = nCount; M!REygyx  
} F!]lU`z)=  
} 7~5ym15*  
?B}{GL2)  
$h*L=t(  
/* 8n*.).33  
**Utility.java <w)r`D6  
*/ U'<KC"f:'!  
package NetFox; /Sc l#4bW  
'lEA)&d  
fvdU`*|n)  
public class Utility { B(n{e53 9f  
hHT_V2*  
.ZJRO>S  
public Utility() k[:bQ)H  
{ <U!`J[n%  
4Za7^c.  
8&)DE@W  
} w-t8C=Z  
xT+zU}z  
//线程睡眠 B#.L  
public static void sleep(int nSecond) 6y9t(m  
{ !g(KK|`,m  
try{ QT>`^/]d  
Thread.sleep(nSecond); U8LtG/  
} G"Sd@%W(  
catch(Exception e) er!DYv  
{ :[hgxJu+  
e.printStackTrace (); |~X ;1j!  
} L;'"A#Pa  
} ]y1OFKYv  
Vp3ZwS  
//日志 h3z{(-~y  
public static void log(String sMsg) ?6fnpGX@a  
{ @AIaC-,~]  
System.err.println(sMsg); M>i9i -dU  
} >76\nGO  
VBcy9|lD  
OeS\7  
public static void log(int sMsg)  ng_^  
{ y*tZ !m2Gg  
System.err.println(sMsg); C ihAU"  
} /p+>NZ"b  
} 'Pn3%&O$  
 Pyb Z)5u  
Od5JG .]  
/* /M3Y~l$  
**TestMethod.java (tZrw5 @  
*/ JSTuXW  
package NetFox; .MJofE;Jn  
"F.;Dv9V[0  
/q5v"iX]T  
public class TestMethod { 37|&?||  
3P^sM1  
R)RG[F#   
public TestMethod() }5}.lJ:  
{ ///xx/weblogic60b2_win.exe =W BTm  
try{ 6u7?dG'4  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pm_u  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fi$-;Gz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); sU@nc!&Y@  
fileFetch.start(); Ux}(?Z  
} Bhp-jq'!B  
catch(Exception e){e.printStackTrace ();} _PlKhv}  
)Ccq4i  
Z3& _  
} w &(|e <  
f=mZu1(FZ  
2|}+T6_q  
public static void main(String[] args) Q^e}?v%=%3  
{ Y<Fz)dQo  
new TestMethod(); {O`w,dMOI  
} '4|-9M3f  
} }9W4"e2)  
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