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http断点续传简单实现(java)

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/* /ruf1?\,R  
**SiteFileFetch.java mefmoZ  
*/ lwY{rWo  
package NetFox; > T-O3/KN  
import java.io.*; ,B#Y9[R  
import java.net.*; ^m+W  
,gOQI S56  
;etQ  
public class SiteFileFetch extends Thread { ttsB'|p s  
gMGg9U$@  
aDOH3Ri0K!  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1|nB\xgu  
long[] nStartPos; //开始位置 E{fnh50^Q.  
long[] nEndPos; //结束位置 4O`h%`M  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 &(rd{j/*  
long nFileLength; //文件长度 }w-`J5Eq#  
boolean bFirst = true; //是否第一次取文件 >bZ#  
boolean bStop = false; //停止标志 qXhrK /  
File tmpFile; //文件下载的临时信息 OK)0no=OAK  
DataOutputStream output; //输出到文件的输出流 X,fTzkGj  
p|FX_4RjX  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) O#EBR<CuK  
public SiteFileFetch(SiteInfoBean bean) throws IOException ZGbZu  
{ <+$S{Z.  
siteInfoBean = bean; `UI)H*GA8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); > Qtyw.n  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .lFSFJ??  
if(tmpFile.exists ()) IRU2/Ycg  
{ R/wSGP`W  
bFirst = false; s{,e^T  
read_nPos(); /,>.${,;u  
} X<QE]RZ  
else J6%op{7/  
{ ^KaMi_--  
nStartPos = new long[bean.getNSplitter()]; Orb(xLChJ  
nEndPos = new long[bean.getNSplitter()]; kp6x6%{K\  
} M[{Cy[ta  
7_3O]e[8  
lET)<V(Y  
P X0#X=$  
} }dHiW:J>  
u#,]>;  
4bBxZY  
public void run() 9F+bWo_m  
{ >ahj|pm  
//获得文件长度 j41:]6  
//分割文件 z K(5&u  
//实例FileSplitterFetch "EHc&,B`  
//启动FileSplitterFetch线程 kb:C>Y8!sC  
//等待子线程返回 </=PN1=A  
try{ c[y8"M5  
if(bFirst) 1v4kN -  
{ vj b?N  
nFileLength = getFileSize(); m#ie{u^  
if(nFileLength == -1) :mrGB3x{  
{ /trc&V  
System.err.println("File Length is not known!"); h+W^k+~(  
} bS'r}  
else if(nFileLength == -2) )q^vitkjup  
{ 10J*S[n1  
System.err.println("File is not access!"); (J4utw Z  
} %:,=J  
else gQEV;hCO  
{ Ueeay^zN  
for(int i=0;i<nStartPos.length;i++) x-pMT3m\D#  
{ |gVO Iq  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?>y-5B[K/(  
} K7.<,E"M.  
for(int i=0;i<nEndPos.length-1;i++) 3DHm9n+/:  
{ xAjQW=  
nEndPos = nStartPos[i+1]; gAj)3T@  
} wuk7mIJ  
nEndPos[nEndPos.length-1] = nFileLength; q KM]wu0Et  
} ?R(3O1,v^  
} IebS~N E  
5);#\&B  
JqUVGEg  
//启动子线程 )ziQ=k6d6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; nB5[]x'  
for(int i=0;i<nStartPos.length;i++) *lK4yI*%o  
{ 4BT`|(7  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F^YIZ,=p!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %5G BMMn  
nStartPos,nEndPos,i); m%[t&^b}T  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FJLJ;]`7+  
fileSplitterFetch.start(); kpH;D=;  
} Q 8rtZ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R`Lm"5w  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); p*0Ve21i,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #CPPdU$  
nEndPos = " + nFileLength); ;}~=W!yz  
// fileSplitterFetch[nPos.length-1].start(); $5b|@  
#%9]Lq  
'-IT@}  
//等待子线程结束 r?!xL\C\  
//int count = 0; J,O@T)S@  
//是否结束while循环 j/<y  
boolean breakWhile = false;  J31M:<  
tA-B3 ]  
\.c )^QQ  
while(!bStop) yj~"C$s  
{ E aD@clJS  
write_nPos(); =%\6}xPEl<  
Utility.sleep(500); EKPTDKut  
breakWhile = true; ;J(,F:N  
rcZ SC3  
Qu,k  
for(int i=0;i<nStartPos.length;i++) jw[BtRW  
{ XKX,7  
if(!fileSplitterFetch.bDownOver) 4Aew )   
{ n^\;*1%$c@  
breakWhile = false; Qcy`O m^2  
break; 38rZ`O*D  
} 5|CiwQg|,p  
} ZZU8B?)  
if(breakWhile) #( sNk,^Ax  
break; =&pN8PEn\  
&fW=5'  
yCIgxPv|7  
//count++; U"+ ry.3`  
//if(count>4) ig}e@]  
// siteStop(); A+*oT(`  
} E`fssd~  
r0deBRM  
aT!9W'uY  
System.err.println("文件下载结束!"); ?=!XhU .  
} aNC,ccm  
catch(Exception e){e.printStackTrace ();} :bRR(sP  
} Kk>qgi$  
5\0.[W{^  
_IV@^v  
//获得文件长度 6KCmswvE  
public long getFileSize() `Kw"XGT  
{ 4E-A@FR  
int nFileLength = -1; *ZR@ z80i  
try{ AaYrVf 9!  
URL url = new URL(siteInfoBean.getSSiteURL()); TucAs 0-bF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8Wx@[!  
httpConnection.setRequestProperty("User-Agent","NetFox"); Om2X>/V%C  
_P<lG[V  
KWJgW{{v  
int responseCode=httpConnection.getResponseCode(); :6$4K"^1  
if(responseCode>=400) bmVgTm&  
{ W)!{U(X  
processErrorCode(responseCode); 2nU NI U  
return -2; //-2 represent access is error iW@Vw{|i I  
} 1m`tqlFU9  
7~ese+\smG  
DRW.NL o  
String sHeader; sV^h#g~Zb  
S@xsAib0J  
pLQSG}N  
for(int i=1;;i++) )L<?g !j~  
{ Z4AAg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); //M4Sq(  
//Utility.log(in.readLine()); :aq>  
sHeader=httpConnection.getHeaderFieldKey(i); /QXs-T}d  
if(sHeader!=null) aE\BAbD7  
{ '}+X,Usm  
if(sHeader.equals("Content-Length")) LAY)">*49H  
{ Flujwh@rg  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); k,R~oSA'n  
break; z3Y)-  
} id tQXwa  
} te*Y]-&I|/  
else <,pLW~2-"  
break; C6'*/wq  
} 8gtCY~m  
} 3.<6;?  
catch(IOException e){e.printStackTrace ();} G#n^@kc*,  
catch(Exception e){e.printStackTrace ();} Sd\IGy{a  
K-EI?6`xM  
@yn^6cE  
Utility.log(nFileLength); 4 ?@uF[  
(L0 hS'  
_%Jl&0%q  
return nFileLength; UI<PNQvo9  
} n E,gQHw  
9j?hF$L"  
bj7MzlGFy  
//保存下载信息(文件指针位置) ]EM)_:tRf  
private void write_nPos() +:"6`um|  
{ {1@4}R4  
try{ 3 2 1={\X  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2Ph7qEBQ22  
output.writeInt(nStartPos.length); a4jnu:e  
for(int i=0;i<nStartPos.length;i++) ~6:LUM  
{ '!fFI1s  
// output.writeLong(nPos); LA+$_U"Jk  
output.writeLong(fileSplitterFetch.nStartPos); 2rj/wakd  
output.writeLong(fileSplitterFetch.nEndPos); `F2*o47|t  
} $uUb$8 Bu  
output.close(); {"0TO|%x  
} siRnH(^ J  
catch(IOException e){e.printStackTrace ();} BH#C<0="  
catch(Exception e){e.printStackTrace ();} StyB"1y  
}  w{ r(F`  
l<aqiZSY  
,dZ H$  
//读取保存的下载信息(文件指针位置) (]}x[F9l  
private void read_nPos() cPx ~|,)l  
{ \ L9?69B~  
try{ V8nz-DL{  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g^z5fFLg/8  
int nCount = input.readInt(); Tw}?(\ya  
nStartPos = new long[nCount]; B15O,sL&W  
nEndPos = new long[nCount]; @7Rt4}g  
for(int i=0;i<nStartPos.length;i++) vz yNc'  
{ urT/+deR  
nStartPos = input.readLong(); oBRm\8 2|  
nEndPos = input.readLong(); 8tV=fSHd  
} EFRZ% Y  
input.close(); B;z>Dd,Y_x  
} #0?"J)  
catch(IOException e){e.printStackTrace ();} 8g[ (nxI~  
catch(Exception e){e.printStackTrace ();} Ho)t=qn  
} &N/|(<CB  
~ ^rey  
dThn?  
private void processErrorCode(int nErrorCode) d^Zo35X  
{ >?>ubM`,  
System.err.println("Error Code : " + nErrorCode); +Q SxYV  
} uv|eVT3jNs  
%UUp=I  
Ok}{jwJ%W;  
//停止文件下载 o\@ A2r3  
public void siteStop() agU%z:M{  
{ P&[Ft)`  
bStop = true; :jk)(=^  
for(int i=0;i<nStartPos.length;i++) ~{7zm"jN  
fileSplitterFetch.splitterStop(); L9{mYA]q  
;L G %s  
p|h.@do4   
} GhG%>U#&a  
} Sl. KLc@@  
//负责部分文件的抓取 BaWQ<T8p8  
**FileSplitterFetch.java 60hNCVq%  
*/ P\q<d  
package NetFox; R<n8M"B  
L,C? gd@"  
aPD?Bh>JU  
import java.io.*; DA+A >5/  
import java.net.*; s6uF5]M;2  
}g>dn  
HF &h  
public class FileSplitterFetch extends Thread { KjFZ  
ig{A[7qN  
iUeV5cB  
String sURL; //File URL qs6Nb'JvQR  
long nStartPos; //File Snippet Start Position 935-{h@k  
long nEndPos; //File Snippet End Position MB ]#%g&  
int nThreadID; //Thread's ID ~/j$TT"  
boolean bDownOver = false; //Downing is over 4 ss&'h  
boolean bStop = false; //Stop identical &Pu+(~'Q  
FileAccessI fileAccessI = null; //File Access interface b$d J?%W  
5nMkd/  
h^o+E2<]  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &K5C=]4  
{ Y%78>-2 L  
this.sURL = sURL; B;xZ% M]  
this.nStartPos = nStart; "XGD:>Q.  
this.nEndPos = nEnd; W<\kf4Y  
nThreadID = id; r+t ,J|V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 |rr$U  
} snXB`U C  
5z1\#" B[  
~A8qeaP  
public void run() D ?Nd; [  
{ - *:p.(c  
while(nStartPos < nEndPos && !bStop) 5~@?>)TBv  
{ %/UV_@x&  
[3t0M5x w  
Dh hG$  
try{ '8s>rH5[V  
URL url = new URL(sURL); +mJ :PAy4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); = E&b=  
httpConnection.setRequestProperty("User-Agent","NetFox"); zWy ,Om8P  
String sProperty = "bytes="+nStartPos+"-"; If~95fy~c  
httpConnection.setRequestProperty("RANGE",sProperty); XOu+&wOu  
Utility.log(sProperty); c:=7lI  
`%$8cZ-kr  
_R EqT  
InputStream input = httpConnection.getInputStream(); `+roQX.p  
//logResponseHead(httpConnection); C1h#x'k  
y\^@p=e  
O{PW  
byte[] b = new byte[1024]; nAIH`L"X  
int nRead; 5JS ZLC  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) xLA~1ZSVJw  
{ nYOY"'z  
nStartPos += fileAccessI.write(b,0,nRead); +J"'  'cZ  
//if(nThreadID == 1) n4^~gT%b5]  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); L<bYRGz  
} TG1P=g5h  
sB?2*S"X)<  
:~vxZ*a  
Utility.log("Thread " + nThreadID + " is over!"); bAdiA2VF'  
bDownOver = true; j3 6,w[Y:  
//nPos = fileAccessI.write (b,0,nRead); <v]z6B@9!  
} $[[?;g  
catch(Exception e){e.printStackTrace ();} +C'XS{K,#  
} t2"@Ps&1|  
} qv *3A?uzr  
/r276Q  
-7k[Vg?  
//打印回应的头信息 DeH0k[o  
public void logResponseHead(HttpURLConnection con) ^uia`sOP4  
{ a*D,*C5}  
for(int i=1;;i++) v9u<F6  
{ ERF,tLa!  
String header=con.getHeaderFieldKey(i); w'A tf  
if(header!=null) & B}Lo  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); >L^xlm%7o  
Utility.log(header+" : "+con.getHeaderField(header)); | z:Q(d06  
else @!e~G'j%VD  
break; O]t\B *%}  
} %Ys$@dB  
} `AR"!X  
#>=8w9]  
VKy5=2&  
public void splitterStop() Gu5~ DyT`G  
{ GMz8B-vk  
bStop = true; PkTf JQP8  
} [cDbaq,T  
b\:~;  
ZP-dW|<[ x  
} _mXs4  
%4,xx'`  
e8oKn&  
/* f e|g3>/|  
**FileAccess.java >:2}V]/ ;  
*//文件访问(定位,写) $0#6"urG  
package NetFox; h}h^L+4  
import java.io.*; t)} \9^Uo  
|=O1Hn  
dByjcTPA  
public class FileAccessI implements Serializable{ 5X0QxnnV  
W"Z#Fs{n8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 fp{G|.SA  
RandomAccessFile oSavedFile; 8.yCA  
long nPos; c_#*mA"+  
Rv<L#!; t  
^2E hlK^)  
public FileAccessI() throws IOException }%$OU =T  
{ *hF^fxLbl  
this("",0); 09d9S`cS\  
} <#y*h8IZ@t  
wX0l?xdI  
_8^0!,j  
public FileAccessI(String sName,long nPos) throws IOException @ .gPJMA  
{ F}'wH-qp  
oSavedFile = new RandomAccessFile(sName,"rw"); X'x3esw w  
this.nPos = nPos;  D,Lp|V  
oSavedFile.seek(nPos); n?:2.S.8  
} xIL#h@dz  
0Gsu  
i6Qb[\;  
public synchronized int write(byte[] b,int nStart,int nLen) T#@{G,N  
{ H@D;e  
int n = -1; @r<b:?u  
try{ =WK04\H  
oSavedFile.write(b,nStart,nLen); e[{mVhg4E  
n = nLen; 'w.}2(  
} ,hWcytzEw  
catch(IOException e) hm\\'_u  
{ qfYG.~`5  
e.printStackTrace (); w{`Acu  
} PNpu*# Z`  
?v4E<iXs  
K(VW%hV1  
return n; d2~l4IL)~  
} _R^y\1Qu  
ARF\fF|<2  
T@P!L  
} N*_"8LIfi_  
>b48>@~bY  
SE)nD@:  
/* 514Z<omrK  
**SiteInfoBean.java ;iU%Kt  
*/ JoJukoy}F  
package NetFox; g1{/ 5{XI  
?#BV+#(  
\|%E%Yc  
public class SiteInfoBean { u,o1{% O  
_ie.|4k  
*5D3vB*S  
private String sSiteURL; //Site's URL xE1'&!4O  
private String sFilePath; //Saved File's Path /e1(? 20  
private String sFileName; //Saved File's Name aQUGNa0+d  
private int nSplitter; //Count of Splited Downloading File pOA!#Aj)  
BpH%STEN  
3vW4<:Lgy  
public SiteInfoBean() :q (&$  
{//nSplitter的缺省值为5 ',)7GY/n~  
//default value of nSplitter is 5 fF;h V  
this("","","",5); f%XJ;y\,9H  
} W~ruN4q.  
4h8*mMghs  
bL`eiol6  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ? ?[g}>  
{ exZLj0kvF  
sSiteURL= sURL; LZ<[ll#C  
sFilePath = sPath; ~3CVxbB^<  
sFileName = sName; IQnIaZ  
this.nSplitter = nSpiltter; n]yEdL/1  
ashar&'  
x[i`S8D  
} PeTA$Yl  
e2w&&B-  
EzpFOqJG  
public String getSSiteURL() 5=L} \ankn  
{ gXy -Mpzp  
return sSiteURL; Ef@,hX  
} ss iokLE  
V.=lGhi  
b>11h  
public void setSSiteURL(String value) fS=hpL6]@  
{ O{]9hm(tN  
sSiteURL = value; JOD/Raq.1k  
} I g \#f  
dRaOGm)  
41V e}%  
public String getSFilePath() =\3Tv  
{ mL yBm  
return sFilePath; i9A~<  
} [4Q"#[V&9  
:O-1rD  
+L%IG  
public void setSFilePath(String value) Hd &{d+B  
{ C6  "  
sFilePath = value; ,6,]#R :J  
} m3.sVI0I  
Q(Gl{#b  
nwmW.(R4  
public String getSFileName() GF$`BGW  
{ x#H 3=YD*  
return sFileName; ;\{`Ci\  
} f_=~H<j!  
EWj gI_-  
"%6/a7S  
public void setSFileName(String value) V/%~F6e  
{ V diJ>d[  
sFileName = value; =L]Q2V}  
} w$fJ4+  
zpjqEEY;  
{38bv. 3'  
public int getNSplitter() o{WyQ&2N  
{ n<7q`tM#  
return nSplitter; v)X\GmW7w  
} SA"8!soY3  
J'T=q/  
;zH HIdQ>-  
public void setNSplitter(int nCount) 'T8W!&$  
{ #,NvO!j<4  
nSplitter = nCount; L.'}e{ldW  
} h2Bz F  
} fV\]L4%  
DN] v_u+}  
)> a B  
/* 5&!c7$K0  
**Utility.java |> enp>  
*/ ~d >W?A  
package NetFox; v& $k9)]  
[wnDHy6W  
,5Vt]#F5@  
public class Utility { jp2Q 9Z  
r'7LR  
S<wj*"|.s  
public Utility() j2 %^qL  
{ \cJa;WM>  
PkuTg";  
(5Nv8H8|  
} +0l`5."d  
2?q(cpsN  
//线程睡眠 "sUyHt-&  
public static void sleep(int nSecond) h*i9m o  
{ 5Wx~ZQZ  
try{ aHzHvl  
Thread.sleep(nSecond); b;cMl'  
} E%N2k|%8d_  
catch(Exception e) zZ-\a[F  
{ r(A.<`\   
e.printStackTrace (); \}0-^(9zd  
} f58?5(Dc|  
} 2{|$T2?e  
{Qu"%h.Al  
//日志 2}U!:bn(  
public static void log(String sMsg) KzU lTl0  
{ muON> ^MbC  
System.err.println(sMsg); <@v ]H@ E  
} ]; $] G-  
5*g]qJF  
9LC&6Q5O&  
public static void log(int sMsg) i5}4(sV  
{ 5 `D-  
System.err.println(sMsg);  t+uE  
} (qM j-l  
} ,M5}4E7L%s  
wf.T3  
JYb}Zw;  
/* Z~  
**TestMethod.java _l`e#XbG  
*/ ,5 j"ruZ  
package NetFox; B=f,QU  
s"KJiQKGM  
),:c+~@@kT  
public class TestMethod { ~ Heb1tl ;  
R\3VB NX.g  
K$ }a8rH  
public TestMethod() dq;|?ESP  
{ ///xx/weblogic60b2_win.exe xgu `Q`~  
try{ OHr Y(I6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ZD/jX_!t  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); g`^X#-!(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); bBcp9C)iY  
fileFetch.start(); &C<yfRDu  
} )j l 8!O7  
catch(Exception e){e.printStackTrace ();} VSX@e|Nj  
K6JVg$  
]  ]U<UJ  
} Z4K+ /<I  
C BYX]  
PQmq5N6  
public static void main(String[] args) $lA V6I.  
{ rf:XRJ <4  
new TestMethod(); @oP_;G  
} #65^w=Sp}  
} ? 8aaD>OR$  
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