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http断点续传简单实现(java)

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/* >}k*!J|  
**SiteFileFetch.java |$.?(FZYu  
*/ 'CBwE&AL  
package NetFox; ~tUZQ5"  
import java.io.*; ~z^l~Vyg?  
import java.net.*; =^"Sx??V  
t Cuvb  
^&3vGu9  
public class SiteFileFetch extends Thread { bLT3:q#s  
s/1r{;q  
+U fw  
SiteInfoBean siteInfoBean = null; //文件信息Bean Ff<cY%t  
long[] nStartPos; //开始位置 ] 0i[=  
long[] nEndPos; //结束位置 b[vE!lJEq  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Aez2n(yac  
long nFileLength; //文件长度 %Z;RY5  
boolean bFirst = true; //是否第一次取文件 ;NP-tA)  
boolean bStop = false; //停止标志 +o+f\!  
File tmpFile; //文件下载的临时信息 ,Csdon  
DataOutputStream output; //输出到文件的输出流 1$Up7=Dr=  
{/[@uMS_6]  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) aru2H6  
public SiteFileFetch(SiteInfoBean bean) throws IOException k?cX f j&  
{ DVQr7tQf  
siteInfoBean = bean; =i~ = |K!  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5{H)r   
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Vmz#u1gGT6  
if(tmpFile.exists ()) p{?duq=  
{ t%@iF U;}  
bFirst = false; Z@Rqm:e  
read_nPos(); :GvC#2 p  
} COi15( G2  
else -=-^rQx9  
{ Yjg$o:M  
nStartPos = new long[bean.getNSplitter()]; Vy& X1lG:  
nEndPos = new long[bean.getNSplitter()]; Hc/7x).  
} c((3B  
_0[z xOI  
za>%hZf\  
 hyxv+m[  
} M:O*_>KF  
mbAzn  
Eu |/pH=:  
public void run() e {6wFN  
{ s.(.OXD&  
//获得文件长度 E2Sj IR}  
//分割文件 hn.(pI1  
//实例FileSplitterFetch W{Qb*{9  
//启动FileSplitterFetch线程 ->#wDL!6  
//等待子线程返回 fD%/]`y  
try{ TT/=0^"  
if(bFirst) Eq@sU?j  
{ 2NFk#_9e~  
nFileLength = getFileSize(); {9J|\Zz3  
if(nFileLength == -1) "]^U(m>f  
{ $%U}k=-  
System.err.println("File Length is not known!"); fe\'N4  
} /{({f?k<\/  
else if(nFileLength == -2) %2RXrH2&H  
{ `+=Zq :0  
System.err.println("File is not access!"); x~'_;>]r_  
} +4J'> dr  
else DN9x<%/-  
{ A?tCa*b^  
for(int i=0;i<nStartPos.length;i++) '"Cqq{*  
{ ,%Pn.E* r;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 02 FLe*zQ  
} QVn2`hr  
for(int i=0;i<nEndPos.length-1;i++) 5hqXMs  
{ TrZ!E`~  
nEndPos = nStartPos[i+1]; 0gyvRM@ x[  
} <S_0=U  
nEndPos[nEndPos.length-1] = nFileLength; =}ZY`O*/  
} w2$ L;q  
} ?:q"qwt$F  
0#c-qy  
jHMP"(]  
//启动子线程 K[SzE{5=P  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Uq=Rz8hLM  
for(int i=0;i<nStartPos.length;i++) MPp:EH  
{ ;[zZI~wh  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vU/sQt8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %to.'R  
nStartPos,nEndPos,i); )p!") :'fv  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); h1)+QLI  
fileSplitterFetch.start(); 4YOLy\"S  
} E=v4|/['N  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +Km xo4p  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); GNG.N)q#C  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", C#&b`  
nEndPos = " + nFileLength); bz&9]% S<  
// fileSplitterFetch[nPos.length-1].start(); 'o_ RC{k2"  
I%?M9y.u6  
?`*`A9@  
//等待子线程结束 J_ h\tM  
//int count = 0; acpc[ ^'  
//是否结束while循环 <!u(_Bxw/  
boolean breakWhile = false; DL_M#c`<  
EY1L5 Ba.  
L8;`*H  
while(!bStop) "| oW6@  
{ rI:]''PR  
write_nPos(); I1ibrn  
Utility.sleep(500); -r_Pp}s  
breakWhile = true; B*Q.EKD8s  
I7ySm12}  
+c'I7bBr  
for(int i=0;i<nStartPos.length;i++) 7 dG_E]&  
{ ^w RD|  
if(!fileSplitterFetch.bDownOver) t/"9LMKs?  
{ (+\K  
breakWhile = false; {XS2<!D  
break; ku5g`ho  
} vCR\lR+  
} 1 pzd  
if(breakWhile) [h :FJ  
break; :n?}G0y  
0xutG/-&N  
Ks7kaX  
//count++; 7w"YCRKh  
//if(count>4) p4zV<qZ>e  
// siteStop(); [TpW$E0H  
} i `8Y/$aT  
w*N9p8hb]  
jr5x!@rb  
System.err.println("文件下载结束!"); "V_PWEi  
} Y)4D$9:  
catch(Exception e){e.printStackTrace ();} |c>A3 P$=B  
} t #g6rh&  
}oTac  
;c>Rjg&[  
//获得文件长度 K>$od^f%c  
public long getFileSize() seH#v  
{ *SZ*S %oS3  
int nFileLength = -1; M*c`@\  
try{ aKCXV[PO   
URL url = new URL(siteInfoBean.getSSiteURL()); >&9Iy"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {z%%(,I  
httpConnection.setRequestProperty("User-Agent","NetFox"); v4< x 4  
ex2*oqAdX  
L``K. DF  
int responseCode=httpConnection.getResponseCode(); yyHr. C  
if(responseCode>=400) Om2 )$(  
{ UIv 2wA2  
processErrorCode(responseCode); 'x10\Q65[  
return -2; //-2 represent access is error |5,q54d(K  
} R\=y/tw0H  
F3a"SKMW  
D &wm7,  
String sHeader; *%cI,}%   
T3{qn$t8  
FyQ^@@  
for(int i=1;;i++) DI!l.w5P_  
{ D`.CXFI+U  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); gGdZ}9  
//Utility.log(in.readLine()); UeT"v?zP  
sHeader=httpConnection.getHeaderFieldKey(i); ^f1}:g  
if(sHeader!=null) R16" lG  
{ ? B^*YCo7(  
if(sHeader.equals("Content-Length")) g;bkV q  
{ 1}!f.cWV(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); =N n0)l  
break; H1=R(+-s  
} ]0dp^%  
} rYq8OZLi  
else ?(U> )SvF  
break; TZZ qV8  
} c-avX  
} D x Vt  
catch(IOException e){e.printStackTrace ();} W~Mj6c~S"  
catch(Exception e){e.printStackTrace ();} .)u,sYZA|  
$- #M~eZv  
iygdX2  
Utility.log(nFileLength); e v?Hz8Q;(  
Mi 'eViH  
: ZU  
return nFileLength; #ZGWU_l}  
} K=Fcy#, f  
Khw!+!(H  
+|( eP_  
//保存下载信息(文件指针位置) R_ 4600  
private void write_nPos() /tP"r}l   
{ 0/(YH  
try{ vC J  
output = new DataOutputStream(new FileOutputStream(tmpFile)); R`>E_SY  
output.writeInt(nStartPos.length); Nc]oA Y  
for(int i=0;i<nStartPos.length;i++) UXa3>q>  
{ 6z=:x+m  
// output.writeLong(nPos); m=NX;t  
output.writeLong(fileSplitterFetch.nStartPos); /2?GRwU~P  
output.writeLong(fileSplitterFetch.nEndPos); {u46m  
} l!q i:H<=1  
output.close(); ycCEXu2F  
} 4"wuqr|o  
catch(IOException e){e.printStackTrace ();} R4QXX7h!  
catch(Exception e){e.printStackTrace ();} {?BxVDD07  
} tM ]qR+  
='OPU5(;O  
'ei9* 4y  
//读取保存的下载信息(文件指针位置) aCFO ]  
private void read_nPos() Sjj &n S  
{ o $p*C  
try{ S4`uNB#Ht  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); MWsBZJRr  
int nCount = input.readInt(); =}U`q3k  
nStartPos = new long[nCount]; W)w@ju$Ko  
nEndPos = new long[nCount]; kV6T#RVob  
for(int i=0;i<nStartPos.length;i++) ?OvtR:hC  
{ ,p>=WX  
nStartPos = input.readLong(); OES+BXGX  
nEndPos = input.readLong(); }r*t V)  
} IM)\-O\Wd  
input.close(); (+bk +0  
} E@P8-x'i  
catch(IOException e){e.printStackTrace ();} xC!,v 0&  
catch(Exception e){e.printStackTrace ();} zn>*^h0B  
} d5+ (@HSR  
:%)l* [  
AXz'=T}{  
private void processErrorCode(int nErrorCode) XrtB&h|C  
{ &FIPEe#n  
System.err.println("Error Code : " + nErrorCode); 4wMKl6mL  
} r/+ <_3  
W9{6?,]  
6 }qNH29  
//停止文件下载 E,u@,= j  
public void siteStop() Yep(,J~'  
{ P0 DvZV8  
bStop = true; #: w/vk  
for(int i=0;i<nStartPos.length;i++) M8:gHjwsx  
fileSplitterFetch.splitterStop(); @q],pD  
Pfe&wA't  
S;MS,R  
} g  O,X  
} QrHI}r  
//负责部分文件的抓取 D#1'#di*t  
**FileSplitterFetch.java 'kL>F&|  
*/ DL_2%&k/  
package NetFox; N3TkRJZ  
t+W+f  
/^ hB6_'D  
import java.io.*; 7y&Fb  
import java.net.*; +kd88Fx  
oXK`=.\  
J}hi)k  
public class FileSplitterFetch extends Thread { $e_A( |  
>mgbs>  
wtndXhVC4>  
String sURL; //File URL 's8NO Xlj  
long nStartPos; //File Snippet Start Position %XMrS lSOp  
long nEndPos; //File Snippet End Position 3YR6@*!f/  
int nThreadID; //Thread's ID [kMXr'TyPX  
boolean bDownOver = false; //Downing is over PBTGN;y  
boolean bStop = false; //Stop identical Y]0oF_ :7  
FileAccessI fileAccessI = null; //File Access interface !r,ZyJU  
iKu[j)F  
PnJr  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException  2(YZTaY  
{ _~d C>`K  
this.sURL = sURL; KIps {_J[<  
this.nStartPos = nStart; t^)q[g  
this.nEndPos = nEnd; #9,!IW]l  
nThreadID = id; {l-,Jbfi`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 gz;().{  
} |qE"60&"}  
d7g/s'ZHt6  
^VR1whCrx  
public void run() >&f .^p  
{ i44UqEb  
while(nStartPos < nEndPos && !bStop) '""qMRCm  
{ 2^Tj7@  
R4"["T+L`  
7]_UZ)u  
try{ OY*BVJ^  
URL url = new URL(sURL); Uq 2Uv  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +[V[{n  
httpConnection.setRequestProperty("User-Agent","NetFox"); su<_?'uH  
String sProperty = "bytes="+nStartPos+"-"; g^26Gb.  
httpConnection.setRequestProperty("RANGE",sProperty); &THM]3:  
Utility.log(sProperty); L}ud+Wfox  
8)&H=#E  
C"PN3>x}j  
InputStream input = httpConnection.getInputStream(); 6A7UW7/  
//logResponseHead(httpConnection); #m1e_[   
2mP| hp?  
: FF:{&d  
byte[] b = new byte[1024]; [ -bL>8  
int nRead; AMA :hQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Ih!UL:Ckh  
{ yHLc lv  
nStartPos += fileAccessI.write(b,0,nRead); M. 1R]x( |  
//if(nThreadID == 1) eC%.xu^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %?J\P@  
} 9Xmb_@7b}  
dt{ |bQLu3  
,miU'<8tQ|  
Utility.log("Thread " + nThreadID + " is over!"); W%hdS<b  
bDownOver = true; J)Dw`=O0n  
//nPos = fileAccessI.write (b,0,nRead); Hq8<g$  
} 3!`Pv ?|o  
catch(Exception e){e.printStackTrace ();} di]z  
} r.** z j  
} "\Jq2vM  
b[$%Wg  
-v8Jn# f  
//打印回应的头信息 $]:I1I  
public void logResponseHead(HttpURLConnection con) S;M'qwN  
{ d{0b*l%  
for(int i=1;;i++) H@bra~k-  
{ f/H rO6~k%  
String header=con.getHeaderFieldKey(i); [Tby+pC  
if(header!=null) zLc.4k  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -`n>q^A7e  
Utility.log(header+" : "+con.getHeaderField(header)); cEnkt=  
else >Bq;Z}EV  
break; I7r{&X) D  
} d*,% -Io  
} AT}}RE@vq  
xcnHj1r-o'  
yBE1mA:x7:  
public void splitterStop() 8jd<|nYnfc  
{ ji? 0;2Y  
bStop = true; 91r9RG>  
} 25BW/23}e  
p18-yt; 1  
NoO>CjeFb  
} 'Y(#Yxc  
P0~3<h?U8  
2!\y0*}K  
/* 5#g<L ~  
**FileAccess.java SKuZik_  
*//文件访问(定位,写) [&|Le;h  
package NetFox; Bwjd/id q  
import java.io.*; V2g,JFp&  
Ziu f<X{  
kFgN^v^t  
public class FileAccessI implements Serializable{ 7{RI`Er`  
4q/E7n  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Msn)jh  
RandomAccessFile oSavedFile; >9a%"<(2#  
long nPos; UBOCd[  
R"6Gm67t  
aO.'(kk8  
public FileAccessI() throws IOException 9-o{[  
{ auAST;"Z8  
this("",0); )wP0U{7?v  
} ^%~ztn 51  
rtvuAFiH  
Y:&1;`FBZ  
public FileAccessI(String sName,long nPos) throws IOException JmrQDO_(  
{ k^Tu9}[W1  
oSavedFile = new RandomAccessFile(sName,"rw"); %2^C  
this.nPos = nPos; l<PGUm:_  
oSavedFile.seek(nPos); [P OcO  
} g,Kb9['  
v|VY5vN  
j$T2ff6  
public synchronized int write(byte[] b,int nStart,int nLen) -le:0NUwI  
{ $qD8vu )|j  
int n = -1; F) {f{-@)  
try{ G(JvAe]r  
oSavedFile.write(b,nStart,nLen); {-^>) iJqt  
n = nLen; \cPGyeq  
} <E$P  
catch(IOException e) /AJ ^wY  
{ UL; d H  
e.printStackTrace (); V J){@  
} .Y_RI&B!L  
m{mK;D  
[4kx59J3b  
return n; wz.Il-sm  
} )jR:\fe  
3Aaj+=]W  
YM3oqS D  
} }tft@,dIC  
zN].W\("\  
ETH`.~%  
/* EM vV  
**SiteInfoBean.java >G' NI?$  
*/ PHDKx+$  
package NetFox; lADi  
cIl^5eE^Pq  
_ H$ Cm  
public class SiteInfoBean { j0 =`Jf  
R{!s%K&  
j V:U%  
private String sSiteURL; //Site's URL <2A4}+p:  
private String sFilePath; //Saved File's Path m f4@g05  
private String sFileName; //Saved File's Name &wNN| fH  
private int nSplitter; //Count of Splited Downloading File ?j8CkqX!  
`U2PlCf |  
rM[Ps=5  
public SiteInfoBean() &_" 3~:N8k  
{//nSplitter的缺省值为5 QV{Nq=%]  
//default value of nSplitter is 5 T]Tz<w W(  
this("","","",5); SnQ$  
} F`Q,pBl1p6  
"^_p>C)T  
"kP.Kx!  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) l-t:7`=|  
{ L4Nk+R;  
sSiteURL= sURL; &JfyXM[]  
sFilePath = sPath; >GT0 x  
sFileName = sName; D-ug$ZRg  
this.nSplitter = nSpiltter; px4Z  
hJFQ/(  
Ba`]Sm=  
} bI]1!bi]i  
((.PPOdJV  
]PUyX8'~  
public String getSSiteURL() .]r[0U  
{ U?#6I-  
return sSiteURL; 'd(}bYr)  
} 6K`frt  
f$2lq4P{  
.WyI.Y1  
public void setSSiteURL(String value) y;<jE.7>  
{ <LBMth  
sSiteURL = value; k9}im  
} j{p0yuZ)<  
F<'g6 f  
" Jv&=zJ  
public String getSFilePath() i]Kq  
{ .YS[Md{  
return sFilePath; 5fVdtJk7  
} <6(u%t0k5  
v+Mt/8  
%eD&2$q*  
public void setSFilePath(String value) `uzRHbJ`  
{ l l&iMj]  
sFilePath = value; Gc@ENE f  
} I*ho@`U  
uidE/7  
r43dnwX  
public String getSFileName() yGS._;#R  
{ jRgv 8n  
return sFileName; f, ;sEV  
} 4=q\CK2^A  
Bb-x1{t  
W:9L!+m^  
public void setSFileName(String value) ENqJ9%sk7  
{ xhimRi  
sFileName = value; A`OU} 'v?L  
} v{%2`_c  
>aa-ix &  
:=~([oSNW"  
public int getNSplitter() N k^#Sa?  
{ y#x]?%m  
return nSplitter; N:&^ql4  
} !sR`]0  
{ 0Leua  
"]JS,g {m  
public void setNSplitter(int nCount) C/]0jAAE7  
{ @Vb-BC,  
nSplitter = nCount; cT.1oaAM0  
} T}4RlIZF  
} "I+wU`AIek  
CZbp}:|  
-ud!j  
/* ~~yo& ]  
**Utility.java sq :ff  
*/ BJ{mX>I(  
package NetFox; _jnH!Mw  
eb+[=nmP  
L*L3;y|  
public class Utility { BQw#PXp3  
k6*2= xK~  
ux-Fvwoh  
public Utility() .;$/nz6vk  
{ \UN7lDH  
3YRhqp"E  
\mv7"TM  
} G]5'U"cj3  
,gRsbC  
//线程睡眠 neOR/]  
public static void sleep(int nSecond) 5$zC,g*#  
{ vw+ @'+  
try{ *a+~bX)18  
Thread.sleep(nSecond); T_I"Tsv  
} xJZbax[  
catch(Exception e) IURi90Ir  
{ "4L' 2w+  
e.printStackTrace (); (5'qEi ea  
} =">O;L.xj  
} J6::(0HM  
FtE%<QHt  
//日志 (MbI8B>  
public static void log(String sMsg) *S{%+1F  
{ G~YV6??  
System.err.println(sMsg); &HW%0lTs%  
} ~fQ#-ekzqk  
P3@[x  
SRj|XCd  
public static void log(int sMsg) 5H?`a7q N  
{ B4&x?-0ZC  
System.err.println(sMsg); Ok O;V6`  
} 9I9J}&4  
} ggX'`bK  
v#D9yttO{  
dkRJ^~  
/* ,uuQj]Dac+  
**TestMethod.java QJ pUk%Wj  
*/ <W\~A$  
package NetFox; Yc\;`C  
~vaV=})  
$NJi]g|<3  
public class TestMethod { hwkol W  
nQg6 j Zf  
'du:Bxl`d4  
public TestMethod() J%D'Xlb  
{ ///xx/weblogic60b2_win.exe q4(&.Al\@  
try{ "hpK8vQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); b^^Cj(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6}{2W<  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _vvnxG!x&  
fileFetch.start(); .ay K+6I  
} c9i CH~  
catch(Exception e){e.printStackTrace ();} WihOGdUS6  
%E~4Ur  
`h :&H,N  
} I=Ws /+  
j[) i>Qw  
wxr93$v  
public static void main(String[] args) g :e|  
{ 56&s'  
new TestMethod(); h Sr#/dw&  
} XQ,I Ej|  
} d/Fjs0pt  
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