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http断点续传简单实现(java)

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/* UZdGV?o ?  
**SiteFileFetch.java +_L]d6  
*/ iZLy#5(St  
package NetFox; '4Jf[  
import java.io.*; #M||t|9iu?  
import java.net.*; J'ZC5Xr  
#UE}JR3g  
'ieTt_1.G  
public class SiteFileFetch extends Thread { !Rc %  
cQ]c!G|a4  
Wco2i m  
SiteInfoBean siteInfoBean = null; //文件信息Bean *MS$C$HOq  
long[] nStartPos; //开始位置 r.'xqzF/  
long[] nEndPos; //结束位置 @ x .`z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n5%\FFG0M  
long nFileLength; //文件长度 $KQ q~|  
boolean bFirst = true; //是否第一次取文件 YKz#,  
boolean bStop = false; //停止标志 9%Tqk"x?  
File tmpFile; //文件下载的临时信息 )Q62I\  
DataOutputStream output; //输出到文件的输出流 BT&R:_:  
gxhdxSm=2  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) +HPcv u?1  
public SiteFileFetch(SiteInfoBean bean) throws IOException R`Fgne$4  
{ Ph%{h"  
siteInfoBean = bean; SXP(C^?C  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 3"zPG~fY{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); a{ L&RRJ  
if(tmpFile.exists ()) &XV9_{Hm  
{ I-}ms  
bFirst = false; U3C"o|   
read_nPos(); QJj='+R>  
} N,Z*d  
else 4 ob?M:S  
{ P6Y+ u  
nStartPos = new long[bean.getNSplitter()]; .^M#BAt2  
nEndPos = new long[bean.getNSplitter()]; R:+'"dBge  
} M(nzJ  
 ?HRS*  
"-djA,`  
Pro?xY$E)  
} %.hJDX\j  
up+0-!AH  
dOKp:|9G  
public void run() <{k`K[)  
{ ZG 0^O"B0  
//获得文件长度 5+11J[~{  
//分割文件 Lu {/"&)  
//实例FileSplitterFetch G^tazAEfo  
//启动FileSplitterFetch线程 ?_FL 'G  
//等待子线程返回 V'e%%&g~N  
try{ Q 8Hl7__^  
if(bFirst) Wlxmp['Bh  
{ @I-,5F|r  
nFileLength = getFileSize(); @!=Ds'MJC  
if(nFileLength == -1) &ocuZ -5`  
{ JRi:MWR<r  
System.err.println("File Length is not known!"); L {P'mG=4  
} p:TE##  
else if(nFileLength == -2) }ymW};W  
{ ^utOVi  
System.err.println("File is not access!"); =3c?W&:  
} $cIaLq  
else A"ATtid  
{ nhdZC@~E0  
for(int i=0;i<nStartPos.length;i++) .SjJG67OyA  
{ F \ls]luN  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]:#=[ CH  
} r :$tvT*  
for(int i=0;i<nEndPos.length-1;i++) \?]U*)B.r  
{ )2RRa^=&  
nEndPos = nStartPos[i+1]; >t)Pcf|s  
} C 2nmSXV  
nEndPos[nEndPos.length-1] = nFileLength; {j9TzR  
} rbnAC*y8'L  
} QK?V^E  
r@}`Sw]@  
t 86w&  
//启动子线程 {N>ju  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ` @  YV  
for(int i=0;i<nStartPos.length;i++) zwZvKV/g  
{ #lrwKHZ+  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), X+ITW#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), cFw-JM<  
nStartPos,nEndPos,i); l>K+4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cN0 *<  
fileSplitterFetch.start(); 1R3,Z8j'  
} 6`O,mpPu4G  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ru@#s2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); PkrVQH9^w  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 9:4S[mz/hD  
nEndPos = " + nFileLength); w.w{L=p:<"  
// fileSplitterFetch[nPos.length-1].start(); $*942. =Q  
pdRM%ug   
?/OF=C#  
//等待子线程结束 ~*7$aj  
//int count = 0; 0t? o6 e  
//是否结束while循环 o3dqsQE%  
boolean breakWhile = false; )][U6e  
I4G0 !"T+  
LWv<mtuYf  
while(!bStop) b'\Q/;oz>  
{ Q3ty K{JE  
write_nPos(); y<kUGsD  
Utility.sleep(500); &'$Bk5D@G  
breakWhile = true; $ uHQl#!;  
LAlwQ^v|  
{/]2~!  
for(int i=0;i<nStartPos.length;i++) R|8vdZ%@  
{ 6&os`!  
if(!fileSplitterFetch.bDownOver) `jGeS[FhR  
{ xcr2|  
breakWhile = false; GMJ4v S  
break; EjLq&QR.  
} $KYGQP  
} a~7D4G  
if(breakWhile) `s)4F~aVo  
break; V?j,$LixY  
?{qUn8f2  
g %mCg P  
//count++; )]j3-#  
//if(count>4) (DO'iCxlNh  
// siteStop(); s{@R|5  
} G<e+sDQ2  
4W" A*A  
\1!Q.V  
System.err.println("文件下载结束!"); %`C*8fc&  
} BQ0?B*yqd  
catch(Exception e){e.printStackTrace ();} -`I|=lBz{H  
} Cw+boB_tip  
?YW~7zG  
9s^$tgH  
//获得文件长度 QMBT8x/+_'  
public long getFileSize() bFX{|&tHU  
{ KkZx6A)$u  
int nFileLength = -1; M YF ^zheD  
try{ /eQAGFG  
URL url = new URL(siteInfoBean.getSSiteURL()); ^wolY0p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S/XU4i:aV  
httpConnection.setRequestProperty("User-Agent","NetFox"); aDdGhB  
@}H u)HO  
;stuTj@vH  
int responseCode=httpConnection.getResponseCode(); Ab ,^y  
if(responseCode>=400) +r3)\L{U  
{ oIE 1j?  
processErrorCode(responseCode); :EV.nD7  
return -2; //-2 represent access is error m`-);y  
} BuV71/Vb{Q  
P`lv_oV  
t,7%| {  
String sHeader; w w^\_KGu7  
hN2A%ds*(j  
A0Mjk  
for(int i=1;;i++) X(ph$,[  
{ t Ly:F*1i  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); V O:4wC"7  
//Utility.log(in.readLine()); R'v~:wNTNs  
sHeader=httpConnection.getHeaderFieldKey(i); &IQ=M.!r  
if(sHeader!=null) uI-T]N:W8x  
{ 2|>\A.I|=  
if(sHeader.equals("Content-Length")) 9~Dg<wQ  
{ z ?\it(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); m=01V5_  
break; lAU99(GXV  
} .nD#:86M  
} #-;c!<2  
else BTkx}KK  
break; \P.h;|u  
} G]=z ![$  
} _Q5mPBO  
catch(IOException e){e.printStackTrace ();} ~</FF'Xz  
catch(Exception e){e.printStackTrace ();} ,s~l; Gkj  
bgor W"'  
&'z_:Wm  
Utility.log(nFileLength); UTkPA2x  
LU:xmDv  
|'?vlUCd  
return nFileLength; `NW/Z/_  
} V.*TOU{{xh  
BD C DQ  
&zJI~R  
//保存下载信息(文件指针位置) P1mg;!tq  
private void write_nPos() /]`@.mZ9:  
{ U+!RIF[Je  
try{ q}P@}TE  
output = new DataOutputStream(new FileOutputStream(tmpFile)); J9mK9{#q  
output.writeInt(nStartPos.length); <T_3s\  
for(int i=0;i<nStartPos.length;i++) bTD?uX!^@  
{ cT'Bp)a  
// output.writeLong(nPos); XGSFG ~d  
output.writeLong(fileSplitterFetch.nStartPos); 072C!F  
output.writeLong(fileSplitterFetch.nEndPos); C^ )Imr  
} z By%=)`  
output.close(); ;R*-cm  
} w jkh*Y  
catch(IOException e){e.printStackTrace ();} << >+z5D+  
catch(Exception e){e.printStackTrace ();} aRMlE*yW  
} ~n]5iGz  
h]oUY.Pf  
E'LI0fr  
//读取保存的下载信息(文件指针位置) p1KhI;^  
private void read_nPos() DU!T#H7  
{ '3l TI  
try{ fUjo',<s  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fB$a )~  
int nCount = input.readInt(); E`fG9:6l]  
nStartPos = new long[nCount]; Q VTL}AT2:  
nEndPos = new long[nCount]; ;_cTrjMv\  
for(int i=0;i<nStartPos.length;i++) [inlxJD  
{ >-MnB  
nStartPos = input.readLong(); N!K%aH~O  
nEndPos = input.readLong(); ?J:w,,4m  
} <[db)r~c  
input.close();  vywB{%p  
} B(W~]i  
catch(IOException e){e.printStackTrace ();} Uc tlE>X`  
catch(Exception e){e.printStackTrace ();} +dCDk* /m  
} 0/Q_% :  
\jC) ;mk  
%OBW/Ti  
private void processErrorCode(int nErrorCode) 0<m7:D Gd  
{ V+`kB3GV  
System.err.println("Error Code : " + nErrorCode); gRY#pRT6d  
} << 6 GE  
' ##?PQ*u  
A^OwT#  
//停止文件下载 c]9gf\WW  
public void siteStop() mo| D  
{ 5T;LWS  
bStop = true; ahl|N`  
for(int i=0;i<nStartPos.length;i++) Jh\KVmfXN  
fileSplitterFetch.splitterStop(); &nmBsl3Q.  
f-F=!^.  
{lds?AuK  
} 2w.FC  
} #kW=|8X  
//负责部分文件的抓取 WzzA:X  
**FileSplitterFetch.java  ew1L+  
*/ ..`c# O&  
package NetFox; 1ubu~6  
hV7EjQp  
,j%\3g`  
import java.io.*; QEJu.o  
import java.net.*; WESD^FK  
bsQ'kBD  
J||g(+H>  
public class FileSplitterFetch extends Thread { HJl?@& l/  
5sY $  
| xB`cSu(  
String sURL; //File URL S F)$b  
long nStartPos; //File Snippet Start Position @8W@I|  
long nEndPos; //File Snippet End Position ud/!@WG  
int nThreadID; //Thread's ID v<1@"9EH  
boolean bDownOver = false; //Downing is over 84(Jo_9  
boolean bStop = false; //Stop identical .V;,6Vq  
FileAccessI fileAccessI = null; //File Access interface !4p{ b f  
j e\!0{  
d8wGXNd7B  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 8>C4w 5kF  
{ H9T~7e+  
this.sURL = sURL; v^&HZk=(  
this.nStartPos = nStart; #ZZe*B!s_  
this.nEndPos = nEnd; 'Dfs&sm  
nThreadID = id; p\[!=ZXFr\  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 FF8jW1  
} \m7\}Nbz0/  
3/RwCtc  
;#Po}8Y=  
public void run() ?T/4 =  
{ k4s V6f  
while(nStartPos < nEndPos && !bStop) s\d3u`G  
{ <f7 O3 >  
.BP d06y  
0ca0-vY  
try{ mlByE,S2E  
URL url = new URL(sURL); $oW= N   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w[z=x  
httpConnection.setRequestProperty("User-Agent","NetFox"); :%gc Sm  
String sProperty = "bytes="+nStartPos+"-"; ':4ny]F  
httpConnection.setRequestProperty("RANGE",sProperty); 4u5j 7`O  
Utility.log(sProperty); (XOz_K6c%K  
iF`_-t/k  
v/ry" W  
InputStream input = httpConnection.getInputStream(); ranem0KQ)]  
//logResponseHead(httpConnection); phDIUhL$z  
1sXCu|\q  
RC7F/|w.z  
byte[] b = new byte[1024]; Xq1#rK(  
int nRead; %E%=Za  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .w4|$.H  
{ z_'^=9m  
nStartPos += fileAccessI.write(b,0,nRead); n~lB}  
//if(nThreadID == 1) _h1bVd-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Sj ovL@X  
} @JSWqi>  
0eO!,/  
$PM r)U  
Utility.log("Thread " + nThreadID + " is over!"); >9w^C1"  
bDownOver = true; 0s`6d;  
//nPos = fileAccessI.write (b,0,nRead); a @? $#>  
} F.TIdkvp  
catch(Exception e){e.printStackTrace ();} 8fQ~UcT$  
} 2[Bbdg[O  
} ,i*rHMe  
`)O9 '568  
N~|f^#L  
//打印回应的头信息 @6ckB (  
public void logResponseHead(HttpURLConnection con) )nHMXZ>Td  
{ M Q =x:p{  
for(int i=1;;i++) Z&^vEQ  
{ \B')2phE  
String header=con.getHeaderFieldKey(i); -, +o*BP  
if(header!=null) Yh]a4l0  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); bAt!S  
Utility.log(header+" : "+con.getHeaderField(header)); ta&z lZt  
else iB0r+IbR  
break; U,b80%k:  
} vT5GUO{5  
} b$2=w^*  
_U}|Le@ e  
5{-Hg[+9  
public void splitterStop() M0m%S:2  
{ A]"6/Lr9P  
bStop = true; k8E2?kbF  
} uhq6dhhR  
9ZOQNN<ex  
_ (b4|hJ'  
} Wda?$3!^q  
-AnJLFY  
~%\vX  
/* ;R >>,&g  
**FileAccess.java tLJ 7tnB  
*//文件访问(定位,写) , JH*l:7  
package NetFox; #NT~GhWFf  
import java.io.*; LEKE+775  
a3A-N] ;f  
`LFT"qnp  
public class FileAccessI implements Serializable{ a\-5tYo`u  
PM*lnd#J  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V,ZRX}O  
RandomAccessFile oSavedFile; [ GknE#p  
long nPos; UHY)+6qt]  
{(-TWh7V  
*)r_Y|vg  
public FileAccessI() throws IOException (q"S0{  
{ x^3K=l;N  
this("",0); }f> 81[^  
} aQhT*OT{Q  
rDaiA x&  
b0f6?s  
public FileAccessI(String sName,long nPos) throws IOException |{M F o)  
{ O0^Y1l  
oSavedFile = new RandomAccessFile(sName,"rw"); 5UL5C:3R9  
this.nPos = nPos; `iuQ.I  
oSavedFile.seek(nPos); 3 } $9./+  
} M|{KQ3q:9  
TbMlYf]It  
@bkSA  
public synchronized int write(byte[] b,int nStart,int nLen) k;umLyz  
{ g3n>}\xG>  
int n = -1; Uwiy@ T Z  
try{ I-s$U T[p  
oSavedFile.write(b,nStart,nLen); e,vgD kI;  
n = nLen; <O9WCl  
} t2ui9:g4j  
catch(IOException e) Pw|/PfG  
{ #SLi v  
e.printStackTrace (); `5t~ Vlp  
} 99h#M3@!  
/\jRr7 Cd  
-?T|1FA,  
return n; ^-# :T  
} PClwGO8'&  
f$nZogaQ  
ku v<  
} +DT tKj  
.:['&; k  
eF 8um$t9  
/* bB.nevb9p  
**SiteInfoBean.java =Oh/4TbW[  
*/ Y$q--JA  
package NetFox; TAM`i3{D  
r-BqIoVT  
aj+I+r"~  
public class SiteInfoBean { >48)@sS  
&)Wm rF  
\LS s@\$ g  
private String sSiteURL; //Site's URL bir tA{q  
private String sFilePath; //Saved File's Path )Z?\9'6e4  
private String sFileName; //Saved File's Name Y%rC\Ij/i  
private int nSplitter; //Count of Splited Downloading File =>C3IR/  
[Az^i>iH  
nRZ T~S4  
public SiteInfoBean() b|Ed@C  
{//nSplitter的缺省值为5 p t{/|P  
//default value of nSplitter is 5 >>7m'-k%D  
this("","","",5); j|% C?N  
} D2Kh+~l  
n@e|PWu  
$/i;UUd  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) doe u`  
{ fl9J  
sSiteURL= sURL; N'5!4JUI  
sFilePath = sPath; M\9p-%"L  
sFileName = sName; {u7_<G7  
this.nSplitter = nSpiltter; [\i1I`7pE  
Q5v_^O<!  
bF3}L=z  
} NE$=R"<Gv  
7^8<[8  
\h/aD1 &g  
public String getSSiteURL() l< |)LD q~  
{ r+l3J>:K  
return sSiteURL; !U+XIr  
} {,m W7  
l3/?,xn  
9s6d+HhM  
public void setSSiteURL(String value) c/}bx52>u  
{ *}i.,4+y   
sSiteURL = value;  F_%&,"$  
} Q,f5r%A.  
*j= whdw%J  
[[:wSAO>6'  
public String getSFilePath() b _0Xi  
{ I%G6V a@  
return sFilePath; FZtIC77X5  
} ;,]Wtmu)7  
[^-DFq5@  
 t"'aQr  
public void setSFilePath(String value) Y_&)>;  
{ C}GOwvAL>  
sFilePath = value; H]W59-{a  
} kO\aNtK  
O7RW*V:G@  
{7X80KI  
public String getSFileName() Vz&!N/0i  
{ ygp NMq#?X  
return sFileName; NvfQa6?;  
} 0l ]K%5#  
Y;XEC;PXD  
:u53zX[v  
public void setSFileName(String value) Q<pL5[00fD  
{ F4Gv=q)Z  
sFileName = value; '`Z5 .<n7p  
} [& &9F};  
n P4DHb&5  
dAcy;-[[P  
public int getNSplitter() ',p`B-dw  
{ `H6kC$^Ofx  
return nSplitter; F&lvofy23  
} RI_3X5.KQ  
ebS>_jD  
!N1DJd  
public void setNSplitter(int nCount) p9)'nU'\t  
{ +K%4jIm  
nSplitter = nCount; e[7n`ka '  
} Hh8)d/D  
} ~O}LAzGb  
v [ 4J0  
@nS+!t{  
/*  + >oA@z  
**Utility.java x-/`c  
*/ ^J]~&.l  
package NetFox; 1yN/+Rq  
hIPU%  
.5zqpm  
public class Utility { Og`w~!\  
bgjo_!J+Pp  
/r Hd9^Y  
public Utility() Hb;#aXHSd  
{ F\Gi;6a  
: )\<  
$>;U^-#3  
} PI#xRKt  
qffXm `k  
//线程睡眠 8I'c83w  
public static void sleep(int nSecond) <O cD[5  
{ jR#g>MDKB  
try{ Q!:J.J  
Thread.sleep(nSecond); iC`K$LY4W  
} !e >EDYbY  
catch(Exception e) N(W ;(7  
{ [s4lSGh  
e.printStackTrace (); z5v)~+"1  
} 7N / v  
} Nj_h+=UE!  
Z`23z( +  
//日志 pN"d~Z8  
public static void log(String sMsg) DUxj^,mf,  
{ ]N^a/&} *  
System.err.println(sMsg); G:QaWqUb  
} @""aNKA^r>  
2#:h.8  
7W6tz\Y  
public static void log(int sMsg) $4y;F]  
{ brGUK PB  
System.err.println(sMsg); ([='LyH];z  
} jd|? aK;(  
} 0S0 ?\r  
2 Ke?*  
u|.L7 3<j%  
/* wPYz&&W  
**TestMethod.java t%wC~1  
*/ wvum7K{tI  
package NetFox; c@%:aiEl  
X/fk&Cp  
e`fN+  
public class TestMethod { LoQm&3/  
#N?EPV$  
xZ} 1dq8  
public TestMethod() -aPvls   
{ ///xx/weblogic60b2_win.exe `g&<7~\=A  
try{ y_:i'Ri.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); C#`VVtei  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Lf|5miO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); F7wpGtt  
fileFetch.start(); eDR4 c%  
} x8xSA*@k  
catch(Exception e){e.printStackTrace ();} ML!Z m[I9  
FV>LD% uu  
)pV5l|`  
} "If]qX(w  
ixZ w;+h  
Gk0f#;  
public static void main(String[] args) #8G (r9  
{ w:P$ S  
new TestMethod(); FWv-_  
} )>$@cH  
} <o8j+G)K#  
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