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http断点续传简单实现(java)

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/* M5xCC!  
**SiteFileFetch.java 5 ~TdD6}  
*/ 3B1cb[2y  
package NetFox; ^^5&QSB:'  
import java.io.*; FQ=@mjh  
import java.net.*; ]('D^Ro  
eImn+_ N3  
0v9rv.Y"  
public class SiteFileFetch extends Thread { HttiX/2~  
lP<:tR~K  
'` pDngX  
SiteInfoBean siteInfoBean = null; //文件信息Bean <~ Sz04  
long[] nStartPos; //开始位置 7)s^8+  
long[] nEndPos; //结束位置 *zr(Zv  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 r$2P;Cxj  
long nFileLength; //文件长度 AhZ8 0!  
boolean bFirst = true; //是否第一次取文件  cReB~wk  
boolean bStop = false; //停止标志 M bb x`  
File tmpFile; //文件下载的临时信息 33!oS&L  
DataOutputStream output; //输出到文件的输出流 o7|eMe?<t  
]xuG&O"SBV  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类)  trAkcYd  
public SiteFileFetch(SiteInfoBean bean) throws IOException <:?r:fQX  
{ OF\rgz  
siteInfoBean = bean; H,b5C_D29  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @|\}.M<e*)  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); =jN *P?  
if(tmpFile.exists ()) }Hn/I,/  
{ O} f80K  
bFirst = false; ^MVkZ{gtre  
read_nPos(); eopD5  
} L'F<ev  
else YCP) %}  
{ z<yU-m2h  
nStartPos = new long[bean.getNSplitter()]; y\ a1iy  
nEndPos = new long[bean.getNSplitter()]; '0FhL)x?"T  
} daYx76yP_?  
@HOBRRm`  
o LvZ   
I :vs;-  
} ra o[VZ  
Yl3n2R /U  
5-M&5f.   
public void run() |`cKD >  
{ zzxGAVu  
//获得文件长度 l,kUhZ@W  
//分割文件 #FNcF>3>  
//实例FileSplitterFetch lyGhdgWc  
//启动FileSplitterFetch线程 a[ex[TRKe  
//等待子线程返回 ,G2TVjz  
try{ uuQ(&  
if(bFirst) o93`|yWl  
{ cJrmm2.0kD  
nFileLength = getFileSize();  -4cXRv]  
if(nFileLength == -1) >(;{C<6|^  
{  rwI  
System.err.println("File Length is not known!"); 5F~'gLH/F-  
} OVV]x{  
else if(nFileLength == -2) NgY =&W,  
{ d!$Z (W0  
System.err.println("File is not access!"); 7k rUKYVo  
} Z:*76PP,  
else <N%7|t*eT  
{ #W|'1 OX4  
for(int i=0;i<nStartPos.length;i++) R=|{n'n$0|  
{ /AW=5Ck-#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l?Ya"C`FL  
} Z-l=\ekJ  
for(int i=0;i<nEndPos.length-1;i++) 8|" XSN  
{ ;A*`e$  
nEndPos = nStartPos[i+1]; %T~ig[GstX  
} v&=gF/$  
nEndPos[nEndPos.length-1] = nFileLength; tQjLOv+?=  
} @~%r5pz6  
} =F@W gn,  
(JM5`XwM  
GSRVe/ [  
//启动子线程 !7kG!)40  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; O)jWZOVp >  
for(int i=0;i<nStartPos.length;i++) 8p:j&F  
{ /bi}'H+#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .dav8n*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), pim!.=vN/U  
nStartPos,nEndPos,i); #H :7@  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hy`?E6=9+  
fileSplitterFetch.start(); gy_>`16K  
} x= 5N3[5  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HbxL:~:}J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |g//g\dd  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", | y2w9n0D  
nEndPos = " + nFileLength); k@'#@ t  
// fileSplitterFetch[nPos.length-1].start(); sPR1?:0:  
MP>dW nl  
v~^{{O  
//等待子线程结束 $GTU$4u  
//int count = 0; fe9LEM8j  
//是否结束while循环 ;t|Ii8Ne  
boolean breakWhile = false; ^G.B+dG@`x  
P9vA7[  
/%;mqrdk  
while(!bStop) {62n7'U{  
{ z& fwE$Nm  
write_nPos(); yp({>{u7  
Utility.sleep(500); m+Rv+_R  
breakWhile = true; K[!&b0O  
s[w6FXt  
;oc&Hb  
for(int i=0;i<nStartPos.length;i++) IWY;="  
{ "t~  
if(!fileSplitterFetch.bDownOver) ;oy-#p>N%  
{ ])nPPf  
breakWhile = false; Y9&,t\ q  
break; rl #p".4q  
} BBtzs^C|  
} rv|)n>m  
if(breakWhile) ]{ntt}3G,  
break; P7{gfiB  
}#n;C{z2e  
orjj' +;X  
//count++; LyAn&h}  
//if(count>4) ZR(x%ews  
// siteStop(); Yj6*NZ*  
} njWL U!  
FW21 U<  
G1o3l~x  
System.err.println("文件下载结束!"); lLF-{  
} #g]vc_V  
catch(Exception e){e.printStackTrace ();} `0Oh_8"  
} T>NDSami  
j 4^97  
!;KCU^9  
//获得文件长度 *tK\R&4,4s  
public long getFileSize() 5) pj]S!]-  
{ Z )SY.iK.  
int nFileLength = -1; s]f6/x/~  
try{ &2{ tF  
URL url = new URL(siteInfoBean.getSSiteURL()); !Rhl f.x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,}K7Dg^1  
httpConnection.setRequestProperty("User-Agent","NetFox"); 61)-cVC  
oz}+T(@O  
U G~ba  
int responseCode=httpConnection.getResponseCode(); }<9cL'  
if(responseCode>=400) TzNn^ir=HX  
{ $3s@}vLd  
processErrorCode(responseCode); {/ BT9|LI  
return -2; //-2 represent access is error "gDb1h)8  
} =*r]) Vg^  
osX8eX]\  
RsY3V=u  
String sHeader; gk0(ANx  
fmb} 2h  
d~1 gMz+)  
for(int i=1;;i++) mqSQL}vR  
{ 4\4FolsK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); lXjXqk\  
//Utility.log(in.readLine()); 7~5ym15*  
sHeader=httpConnection.getHeaderFieldKey(i); K>DR Jz  
if(sHeader!=null) Vnr[}<L  
{ 8n*.).33  
if(sHeader.equals("Content-Length")) <w)r`D6  
{ O8j_0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); )'6DNa[y  
break; t+1 %RyKFB  
} $Z\.-QE\  
} FXi{87F2  
else Y]B)'[=h  
break; WZ*ws[dVI  
} VCD:3U 8  
} H?)w!QX  
catch(IOException e){e.printStackTrace ();} Na?!;1]_  
catch(Exception e){e.printStackTrace ();} fngOeLVG  
vJ-q*qM1  
B#.L  
Utility.log(nFileLength); Y}#J4i0b*  
QT>`^/]d  
U8LtG/  
return nFileLength; 2gCX}4^3b  
} er!DYv  
:[hgxJu+  
+/)#( j@  
//保存下载信息(文件指针位置) S|]X'f  
private void write_nPos() 4'!c*@Y  
{ ?C&z]f3(:  
try{ OslL~<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); JU^lyi!  
output.writeInt(nStartPos.length); ]Zyur`  
for(int i=0;i<nStartPos.length;i++) w[I E  
{ ecCr6)  
// output.writeLong(nPos); T`;%TO*Y  
output.writeLong(fileSplitterFetch.nStartPos); 8(~K~q[Cr  
output.writeLong(fileSplitterFetch.nEndPos); %\H|B0  
} `m!j$,c.  
output.close(); k=4N.*#`y  
} CkdP#}f  
catch(IOException e){e.printStackTrace ();} ^`)) C;  
catch(Exception e){e.printStackTrace ();} PGLplXb#[S  
} ~s]iy9i  
RHO(?8"_  
2E)wpgUc?e  
//读取保存的下载信息(文件指针位置) s0k`p<q  
private void read_nPos() n1VaLD  
{ qT`k*i?  
try{ %Ntcvp)  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); N#DYJ-~*  
int nCount = input.readInt(); q(.:9A*0  
nStartPos = new long[nCount]; b;cdIl!3  
nEndPos = new long[nCount]; C0}IE,]  
for(int i=0;i<nStartPos.length;i++) X@LRsg  
{ -/g B|J  
nStartPos = input.readLong(); GJtZ&H  
nEndPos = input.readLong(); &'}RrW-s  
} 17G'jiY H  
input.close(); znaUBv_  
} 8\5 T3AF  
catch(IOException e){e.printStackTrace ();} [ji#U s:h  
catch(Exception e){e.printStackTrace ();} b{]z w pf  
} LS88.w\=S@  
Zy(W^~NT  
8$;=Uf,x  
private void processErrorCode(int nErrorCode) ]2\VweV  
{ _PlKhv}  
System.err.println("Error Code : " + nErrorCode); )Ccq4i  
} Z3& _  
w &(|e <  
l33Pm/V2?  
//停止文件下载 O^^C;U@U<1  
public void siteStop() qpE&go=k'  
{ -2A(5B9Fq  
bStop = true; _;UE9S%  
for(int i=0;i<nStartPos.length;i++) % Cv D-![0  
fileSplitterFetch.splitterStop(); !`M|C?b  
` M3w]qJ<}  
% <q w  
} t`,` 6@d  
} .[JYj(p  
//负责部分文件的抓取 <\pfIJr$  
**FileSplitterFetch.java t<|NLk.  
*/ I| b2acW  
package NetFox; #~l(]h@ )  
pt?q#EfFJ  
kAC&S!n  
import java.io.*; (r D_(%o  
import java.net.*; T3pmVl  
Ou1JIxZ)|  
%]8qAtV^3j  
public class FileSplitterFetch extends Thread { %+K<<iyR|  
|>JS!NM I  
G6FEp`  
String sURL; //File URL Dqe^E%mc  
long nStartPos; //File Snippet Start Position XAe% m^  
long nEndPos; //File Snippet End Position kZerKP  
int nThreadID; //Thread's ID w$`5g  
boolean bDownOver = false; //Downing is over e^[H[d.WMC  
boolean bStop = false; //Stop identical 1PP $XJtyD  
FileAccessI fileAccessI = null; //File Access interface ~ ArP9 K "  
dRaNzK)M  
}C>{uXv  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _oUHJ~&,  
{ 82QGS$0V  
this.sURL = sURL; /(BMG/Tb  
this.nStartPos = nStart; jr!?v<NoX  
this.nEndPos = nEnd; Lg*B>=  
nThreadID = id; CS=qj-(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (;57Vw  
} 4@ML3d/  
S4h:|jLUF  
.b-f9qc=  
public void run() ##V5-ZG{:  
{ tP2qK_\e=  
while(nStartPos < nEndPos && !bStop) $a"n1ou  
{ s+EAB{w$  
Gmq/3tw  
9J>&29@us0  
try{ nCj2N,mT  
URL url = new URL(sURL); ]5$eAYq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); H+ 0$tHi  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6^"=dn6K  
String sProperty = "bytes="+nStartPos+"-"; 3MY(<TGX  
httpConnection.setRequestProperty("RANGE",sProperty); 24)(5!:"  
Utility.log(sProperty); ZOQTINf  
/s[l-1zW  
eL\;Nf+Zp  
InputStream input = httpConnection.getInputStream(); >ey\jDr#O  
//logResponseHead(httpConnection); 43Qtj$F  
7qg{v9|,  
]jaQ[g$F  
byte[] b = new byte[1024]; [I$ BmGQ  
int nRead; "gne_Ye.  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) g)_e]&  
{ |*'cF-lp6v  
nStartPos += fileAccessI.write(b,0,nRead); v {jQek4  
//if(nThreadID == 1) RQ'H$r.7g  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v%s`~~u%^  
} (''M{n  
~YRDyQ:%T  
r]l!WRn  
Utility.log("Thread " + nThreadID + " is over!"); aP8H`^DFX>  
bDownOver = true; OZTPOz.  
//nPos = fileAccessI.write (b,0,nRead); l#H#+*F  
} 2GWMlI  
catch(Exception e){e.printStackTrace ();} 'iGzkf}j  
} $;/}?QY(  
} MV\|e1B}  
W'.s\e?gh  
>b6-OFJx  
//打印回应的头信息 k?z98 >4  
public void logResponseHead(HttpURLConnection con) a(9L,v#?  
{ A%D7bQ  
for(int i=1;;i++) b r^_'1  
{ Zuw?58RE\  
String header=con.getHeaderFieldKey(i); A Q+]|XYo_  
if(header!=null) _-9@qe  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ?}RSwl  
Utility.log(header+" : "+con.getHeaderField(header)); 6C]1Q.f;  
else S`"LV $8  
break; M\Z6$<H?U  
} bV8!"{  
} z6?)3'  
YR>B_,Gl  
B,K>rCZ/  
public void splitterStop() FcRW;e8-  
{ Ircp``g  
bStop = true; 9f',7i  
} ZP;j9 T!  
_=NwQu\_F  
mN>h5G>a  
} ~d%Pnw|  
FFH_d <q  
)Jk0v_ X  
/* mXUGe:e8  
**FileAccess.java q@@T]V6  
*//文件访问(定位,写) &/uu)v  
package NetFox; &%s8L\?  
import java.io.*; '{J&M|<A  
<YOLxR  
l411a9o  
public class FileAccessI implements Serializable{ O=$~O\}b  
n< ud> JIb  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~<k,#^"}X  
RandomAccessFile oSavedFile; <%Ostqj  
long nPos; C":o/;,1  
'^Ql]% _  
` bdZ/*E  
public FileAccessI() throws IOException .hba*dV  
{ Wt=|  
this("",0); +\|Iu;w  
} _`I "0.B]  
F@*+{1R  
LNa$ X5`  
public FileAccessI(String sName,long nPos) throws IOException `X`2:@gQ  
{ ,Vh{gm1  
oSavedFile = new RandomAccessFile(sName,"rw"); K)-m*#H&uw  
this.nPos = nPos; xw3YK!$sIF  
oSavedFile.seek(nPos); 6X\ 2GC9  
} =Apxdnz,  
66'?&Xx'  
x,otFp  
public synchronized int write(byte[] b,int nStart,int nLen) ~,BIf+ \XF  
{ :sP!p`dl  
int n = -1; 3Ezy %7  
try{ jWY$5Vq<H  
oSavedFile.write(b,nStart,nLen); ?APe R,"V  
n = nLen; 13+<Q \  
} `"@g8PWe  
catch(IOException e) }Y*VAnY6;  
{ u_ '!_T L  
e.printStackTrace (); ]miy/V }5  
} 2 OwV^-OG  
N @#c,,  
EM/@T}  
return n; Cz W:L&t  
} T<L^N+<,{N  
Pf_S[ sm  
E-{^E.w1  
} Cxcr/9  
l%`F&8K  
XO9M_*Va  
/* S_T1y  
**SiteInfoBean.java ]a! xUg!S  
*/ 1|?05<8  
package NetFox; %uoQ9lD'  
X5khCL Hi  
}#qGqY*@LK  
public class SiteInfoBean { V%_4%  
m1IKVa7-\}  
6sE{{,OGB  
private String sSiteURL; //Site's URL !p[9{U->o;  
private String sFilePath; //Saved File's Path g(Io/hyj  
private String sFileName; //Saved File's Name #!$GH_  
private int nSplitter; //Count of Splited Downloading File `c69 ?/5  
K^3co  
^<:sdv>Y5  
public SiteInfoBean() GV^i`r^"  
{//nSplitter的缺省值为5 C-?%uF  
//default value of nSplitter is 5 Q3 eM2i8Y  
this("","","",5); S<L.c  
} W?We6.%  
sz9G3artK&  
<97d[/7i  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) :KKa4=5L  
{ 3 AHY|  
sSiteURL= sURL; |hO~X~P  
sFilePath = sPath; c(/VYMJZ&  
sFileName = sName; shH~4<15  
this.nSplitter = nSpiltter; Khe!g1=&X  
-PnyZ2'Z  
Wfz\ `y  
} gxT4PQDy  
{w8 NN-n  
U^.4Hy&D  
public String getSSiteURL() )OLq_':^ @  
{ TP}h~8 /;  
return sSiteURL; R.s^o]vT  
} eVR5Xar  
i z~ pGkt  
Yyfq  
public void setSSiteURL(String value) g!`3{ /4  
{ AWjm~D-?  
sSiteURL = value; oM)h#8bq  
} w]_zp?\^ }  
[<,~3oRu  
t'~/$=9}  
public String getSFilePath() Lqp8yVO  
{ S#b-awk  
return sFilePath; QnI.zq V  
} >?]_<:  
\NG C$p n  
8LI-gp\ 2  
public void setSFilePath(String value) {Rear 2  
{ JI/_ce  
sFilePath = value; X>I)~z}9#  
} a|BcnYN  
$x#FgD(iI  
D&ve15wL  
public String getSFileName() /oL;YIoQX  
{  x-'~Bu  
return sFileName; XG@`ZJhU6  
} J@ L9p46,  
S|zW^|YU  
M0' a9.d  
public void setSFileName(String value) LrCk*@  
{ '&FjW-`" G  
sFileName = value; E"|4Y(G  
} $2MAZGJV  
a Zk&`Jpz  
y#<MV H  
public int getNSplitter() npDIX  
{ zD)pF1,7:8  
return nSplitter; DOQc"+  
} !>(RK"KWq]  
OI0B:()  
a1.|X i'/z  
public void setNSplitter(int nCount) 8CC/BOe  
{ oW$s xS  
nSplitter = nCount; }Z`(aDH  
} -z:&*=  
} Kv{8iAB#c  
}4>JO""  
D\~e&0*  
/* _ OaRY]  
**Utility.java }#v{`Sn%^C  
*/ ,&YTj>  
package NetFox; Zw] ?.  
 y\F=ui  
=6=_/q2  
public class Utility { %5  
_J]2~b  
r,N[)@  
public Utility() nW+YOX|+  
{ a45 ss7  
^# A.@  
~/IexQB&  
} Y& ] 8 {  
?G08NR  
//线程睡眠 {^Pq\h;  
public static void sleep(int nSecond) x3e]d$  
{ RiO="tX'  
try{ gcJF`H/iNK  
Thread.sleep(nSecond); -@IL"U6  
} \Xt) E[  
catch(Exception e) Ze!92g  
{ [rreFSy#@  
e.printStackTrace (); np WEop>  
} uO >x:*^8  
} 'FzN[% K"  
sl/)|~3!8  
//日志 )~rB}>^Z  
public static void log(String sMsg) i_F$&?)  
{ QfQ\a%cc  
System.err.println(sMsg); }t>q9bZ9z  
} y1BgK>R  
|*,jU;NI  
Gqyue7;0,  
public static void log(int sMsg) ~ E=\t9r  
{ kA7(CqUW  
System.err.println(sMsg); ]=D5p_A(  
} {6xPdUhw  
} m&R"2t_Z  
s6=YV0w(  
LQ-6vrbs  
/* j1$<]f  
**TestMethod.java WA LGIW  
*/ =V|Nn0E  
package NetFox; :w?7j_p#  
WwW^[k (X  
~4)Y#IxL  
public class TestMethod { }#=Od e  
[.q(h/b  
vZajT!h  
public TestMethod() 'H FKBp  
{ ///xx/weblogic60b2_win.exe j[P8  
try{ aQcN&UA@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); kd;'}x=5yP  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Zj-BuE&@f  
SiteFileFetch fileFetch = new SiteFileFetch(bean); A1*4*  
fileFetch.start(); agaq`^[(P  
} 7CrpUh  
catch(Exception e){e.printStackTrace ();} o@d y:AR  
5a(<%Q <"  
wq4nMY:#  
} '1]7zWbW  
;IC'Gq  
KtTza5aF  
public static void main(String[] args) kb|eQtH  
{ bZ# X 9fT  
new TestMethod(); 'Kis hXOn]  
} JJl7JwSTW  
} +$(0w35V5  
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