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http断点续传简单实现(java)

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/* 5Gw!9{ke  
**SiteFileFetch.java NE; (..  
*/ t[f9Z  
package NetFox; PO1:9  
import java.io.*; v)C:E9!|  
import java.net.*; ={mPg+Ei'  
(IoPU+1b  
=E"kv!e   
public class SiteFileFetch extends Thread { V(' 'p{  
ig.6[5a\  
lH,]ZA./  
SiteInfoBean siteInfoBean = null; //文件信息Bean +}`O^#<qLX  
long[] nStartPos; //开始位置 0?5%  
long[] nEndPos; //结束位置 6'No4[F 4n  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 TQ5MKqR$  
long nFileLength; //文件长度 JucxhjV#,  
boolean bFirst = true; //是否第一次取文件 !q=Q~ea  
boolean bStop = false; //停止标志 HYI1 o/}  
File tmpFile; //文件下载的临时信息 bzj!d|T`  
DataOutputStream output; //输出到文件的输出流 +>i<sk  
)bIK0h  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) #v~S",*.f  
public SiteFileFetch(SiteInfoBean bean) throws IOException Q#J>vwi=  
{ R>e3@DQ~  
siteInfoBean = bean; >arO$|W  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .Kh(F 6 s  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Sf4h!ly  
if(tmpFile.exists ())  [A%e6  
{ O=#/DM;  
bFirst = false; 08K.\3  
read_nPos(); o7 @4=m}  
} 9 .&Or4>  
else :,}:c%-^"  
{ ]UCk_zWsn1  
nStartPos = new long[bean.getNSplitter()]; . tH35/r  
nEndPos = new long[bean.getNSplitter()]; ku[=QsMv  
} X>@.-{6T  
c~pUhx1(  
o trTrh  
tXG4A$(2&  
} $5Y^fwIK  
_OknP2E  
Z:B Y*#B  
public void run() c&Su d, &  
{ D $CY:@  
//获得文件长度 Lm*LJ_+ B  
//分割文件 >;'1k'  
//实例FileSplitterFetch I 3zitI;  
//启动FileSplitterFetch线程 ,QHx*~9  
//等待子线程返回 M#lVPXS  
try{ uZ2v;]\Y6  
if(bFirst) s=y9!rr  
{ Ei p~ ~2  
nFileLength = getFileSize(); l=-d K_ I?  
if(nFileLength == -1) \")YKN=W  
{ 9h,yb4jPP  
System.err.println("File Length is not known!"); v4k=NH+w  
} ;aRWJG  
else if(nFileLength == -2) [[66[;  
{ c9g\7L,Z  
System.err.println("File is not access!"); MBYD,v&  
} xU\:Vid+A  
else 1O3<%T#LOZ  
{ c;|&>Fp  
for(int i=0;i<nStartPos.length;i++) 1TxhEXB  
{ AZ]SRz9mKY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]-s`#  
}  ]O9f"cj  
for(int i=0;i<nEndPos.length-1;i++) Uwm[q+sTp  
{ <T.3ZZ%  
nEndPos = nStartPos[i+1]; h'YcNkM 2>  
} RY/ Z~]  
nEndPos[nEndPos.length-1] = nFileLength; A Fm*60C  
} @qhg[= @  
} y1"^S  
MTITIecw=  
Mi/'4~0Y  
//启动子线程 CQuvbAo  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; milK3+N  
for(int i=0;i<nStartPos.length;i++) S5pP"&I[  
{ u, SX`6%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8DS5<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <T_Nlar^^  
nStartPos,nEndPos,i); _8b>r1$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f?<M3P  
fileSplitterFetch.start(); $ E~Lu$|  
} K[|P6J   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `SS~=~WY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z#E,96R  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", NW>:Lz ?"  
nEndPos = " + nFileLength); 08jUVHdt  
// fileSplitterFetch[nPos.length-1].start(); K{w=qJBM  
QsF<=b~  
\FY De  
//等待子线程结束 F=T.*-oS3  
//int count = 0; eg~^wi  
//是否结束while循环 pu)9"Ad[ G  
boolean breakWhile = false; BK\~I  
h }%M  
MVL }[J  
while(!bStop) {FmFu$z+[  
{ u/:Sf*;?  
write_nPos(); 53&xTcv}x  
Utility.sleep(500); \utH*;J|x  
breakWhile = true; dv9Pb5i  
a5~C:EU0  
.idl@%  
for(int i=0;i<nStartPos.length;i++) 3{L vKe  
{ +VW]%6 +  
if(!fileSplitterFetch.bDownOver) 2Ku#j ('  
{ <sFf'W_3{  
breakWhile = false; yExyx?j.  
break; xY'YbHFz  
} leYmV FE  
} 1H[;7@o$e  
if(breakWhile) QEHZ=Yg%3  
break; vAhO!5]>\  
Gc!{%x  
eD1MP<>h  
//count++;  p|8Fl  
//if(count>4) x w83K  
// siteStop(); 7<Js'\Z  
} |Gs-9+'y  
J&Qy$itqg  
{}C7VS1  
System.err.println("文件下载结束!"); EkAqFcKLq  
} yrYaKh  
catch(Exception e){e.printStackTrace ();} ~t3?er& R  
} ,H(vD,54g  
RkV3_c  
Sm_:SF!<D6  
//获得文件长度 _,?HrL9  
public long getFileSize() g(r'Y#U  
{ \*"0wR;[K  
int nFileLength = -1; >)Z2bCe  
try{ 1 'pQ,  
URL url = new URL(siteInfoBean.getSSiteURL()); Cv7RCjMw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~HI0<;r=eL  
httpConnection.setRequestProperty("User-Agent","NetFox"); s ;Nu2aOp7  
5.HztNL  
& ~G  
int responseCode=httpConnection.getResponseCode(); XN%D`tbvJ  
if(responseCode>=400) 3:Egqw  
{ 61wG:  
processErrorCode(responseCode); 128 rly  
return -2; //-2 represent access is error m/B9)JzY  
} GeT CN  
+hhbp'%  
e14 Q\  
String sHeader; I}0 -  
CMjPp`rA  
][qA@3^Tw  
for(int i=1;;i++) ?gP/XjToMg  
{ |-Klh  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \`9|~!,Ix7  
//Utility.log(in.readLine()); { 3P!b|V>  
sHeader=httpConnection.getHeaderFieldKey(i); 9JeGjkG,  
if(sHeader!=null) *<5lx[:4/x  
{ iZ;jn8  
if(sHeader.equals("Content-Length")) sh3}0u+  
{ Ec/+9H6g  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 'N/%SRk  
break; JkEQ@x  
} 8>+eGz|  
} dM.Ow!j  
else >Nqkz?67  
break; @,$HqJ  
} ky"7 ^  
} m{Xf_rQ w  
catch(IOException e){e.printStackTrace ();} 5d;K.O  
catch(Exception e){e.printStackTrace ();} 4[j) $!l`  
o%Q'<0d  
cwU6}*_zn  
Utility.log(nFileLength); r 24]2A  
[o6<aE-  
IN*Z__l8j`  
return nFileLength; &1n0(qB  
} ?Ir6*ZyY  
B|w}z1.  
$jL.TraV7  
//保存下载信息(文件指针位置) L7="!I  
private void write_nPos() !aoO,P#j  
{ aq**w?l  
try{ TK1M mL  
output = new DataOutputStream(new FileOutputStream(tmpFile)); aa3YtNpP  
output.writeInt(nStartPos.length); F&Z>B};  
for(int i=0;i<nStartPos.length;i++) N.J:Qn`(  
{ }z@hx@N/  
// output.writeLong(nPos); TJa%zi  
output.writeLong(fileSplitterFetch.nStartPos); z$,hdZ]  
output.writeLong(fileSplitterFetch.nEndPos); :9>nY  
}  F<1'M#bl  
output.close(); 05DtU!3O  
} 7P(:!ce4-  
catch(IOException e){e.printStackTrace ();} 1O{67Pf  
catch(Exception e){e.printStackTrace ();} R|yTUGY  
} HM x9M$  
_J`M>W)8  
'7%9Sqx  
//读取保存的下载信息(文件指针位置) Jx,s.Z0@7,  
private void read_nPos() S!bvU2d  
{ p[I gnO  
try{ e=C,`&s z  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ]vG)lY.=  
int nCount = input.readInt(); ON^u|*kO  
nStartPos = new long[nCount]; g:V6B/M&  
nEndPos = new long[nCount]; R'_[RHFC  
for(int i=0;i<nStartPos.length;i++) }zLE*b,  
{ -#hl& ^u$  
nStartPos = input.readLong(); d@~)Wlje  
nEndPos = input.readLong(); #-8/|_*  
} +%^xz 1m  
input.close(); EkPSG&6RZ  
} Xp@OIn  
catch(IOException e){e.printStackTrace ();} .- o,_eg1f  
catch(Exception e){e.printStackTrace ();} E_#&L({|@  
} q9Wtu7/  
m{" zFD/  
fe,CY5B{  
private void processErrorCode(int nErrorCode) H$HhB8z3  
{ !ym5' h  
System.err.println("Error Code : " + nErrorCode); Z!6G (zz:>  
} ~Y$1OA8  
^^mi@&ApLD  
_TiF}b!hi  
//停止文件下载 n+w>Qz'  
public void siteStop() "^7Uk#! 7  
{ nfR5W~%*:  
bStop = true; PI?[  
for(int i=0;i<nStartPos.length;i++) pgarGaeq  
fileSplitterFetch.splitterStop(); v\Gu  
QUO?q+  
epePx0N%x$  
} 36z{TWF  
} Sx7xb]3XI"  
//负责部分文件的抓取 pQ JZE7S  
**FileSplitterFetch.java W@LR!EW)  
*/ hHQt4 r'd  
package NetFox; #=c%:{O{4R  
\qPrY.-  
e!y t<[ph  
import java.io.*; 0Oq1ay^  
import java.net.*; {0~ p"%*  
# jyAq$I0  
6C=.8eP  
public class FileSplitterFetch extends Thread { Xb {y*',  
2oRmro  
~5zhK:7c  
String sURL; //File URL 4H)a7 <,  
long nStartPos; //File Snippet Start Position SqLKF<tY]/  
long nEndPos; //File Snippet End Position [ CY=  
int nThreadID; //Thread's ID j@f(cRAf#  
boolean bDownOver = false; //Downing is over U/;Vge8{  
boolean bStop = false; //Stop identical 1>LquZ+Kj  
FileAccessI fileAccessI = null; //File Access interface 0!T $Ef   
:/08}!_:  
K,Vl.-4?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException p_D)=Ef|&  
{ 0&|-wduR=  
this.sURL = sURL; dcsd//E  
this.nStartPos = nStart; 3FfS+q*3S  
this.nEndPos = nEnd; p_( NLJ%  
nThreadID = id; >jm9x1+C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qIl@,8T  
} ! `o =2b=N  
"|H0 X#  
7>TG ]&  
public void run() NUseYU``  
{ A.Njn(z?Lz  
while(nStartPos < nEndPos && !bStop) c s> W6  
{ nN: i{t4f  
^B7Aam  
)deuB5kz  
try{ 2P*O^-zRp  
URL url = new URL(sURL); Qoc-ZC"<6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); TqC"lO>:Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); ;3_'{  
String sProperty = "bytes="+nStartPos+"-"; !!AutkEg>  
httpConnection.setRequestProperty("RANGE",sProperty); (<t)5?@%  
Utility.log(sProperty); f#?R!pR  
<cS1}"  
o z QL2  
InputStream input = httpConnection.getInputStream(); & |r)pl0$  
//logResponseHead(httpConnection); ;NEHbLH#F  
. Hw^Nx  
-Cl0!}P4I  
byte[] b = new byte[1024]; iD9GAe}x  
int nRead; kE1u-EA  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R[6&{&E:  
{ !Wk "a7  
nStartPos += fileAccessI.write(b,0,nRead); &F)lvtt|  
//if(nThreadID == 1) *@< jJP4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *Co+UJjT  
} -c. a7  
b^1!_1c  
_?8T'?-1  
Utility.log("Thread " + nThreadID + " is over!"); o{/D:B  
bDownOver = true; y_w4ei  
//nPos = fileAccessI.write (b,0,nRead); 5E]I  
} %NuS!v>  
catch(Exception e){e.printStackTrace ();} MZ.Jkf(  
} A-kI_&g\Og  
} y~w$>7U.  
%~@}wHMB  
S&yCclM  
//打印回应的头信息 YRl2e`&jt  
public void logResponseHead(HttpURLConnection con) Xv6s,<#\  
{ 2KU [Yd  
for(int i=1;;i++) nX~sVG{Q  
{ Y0DBkg  
String header=con.getHeaderFieldKey(i); DY%E&Vd:h  
if(header!=null) }Q*8QV  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :%{8lanO  
Utility.log(header+" : "+con.getHeaderField(header)); ;G ?_^ 0  
else Z^b1i`v  
break; R lv|DED$  
} S;= D/)[mr  
} |&7l*j(\  
dS-l2 $n  
:`d& |BB  
public void splitterStop() +=*ZH `qX  
{ F2#^5s(  
bStop = true; >R6Me*VR  
} E/ Pa0.  
{?82>q5F  
|zSkQ_?54  
} W n|w~{d{  
FQ_4a}UOjX  
_d: l1jD  
/* l+@NjZGm<  
**FileAccess.java 3S Dw-k  
*//文件访问(定位,写) ]kr OPM/  
package NetFox; =6ojkTk  
import java.io.*; zg|]Ic  
2$|WXYY  
s i C/k*  
public class FileAccessI implements Serializable{ 9R!.U\sq  
WVKzh  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Pr" 2d\  
RandomAccessFile oSavedFile; B?k75G  
long nPos; dx|j,1e  
kZeb^Q+,  
v~j21`  
public FileAccessI() throws IOException |]V0sgpoZ  
{ \S _ycn  
this("",0); Vg0Rc t  
} "gYn$4|R7*  
zXB.)4T  
3(X"IoNQ  
public FileAccessI(String sName,long nPos) throws IOException J 5~bs*a8  
{ ">|fB&~A  
oSavedFile = new RandomAccessFile(sName,"rw"); ?me0J3u_  
this.nPos = nPos; Bc$t`PI  
oSavedFile.seek(nPos); +Bgy@.a?  
} ((#|>W\&  
, j7&(V~  
ZPHB$]ri  
public synchronized int write(byte[] b,int nStart,int nLen) ><%z~s  
{ )jvYJ9s  
int n = -1; *?cE]U6;  
try{ 0P z"[  
oSavedFile.write(b,nStart,nLen); 2 g,UdG  
n = nLen; yy@g=<okt\  
} I;9>$?t[  
catch(IOException e) cZi/bIh  
{ ftRf~5d2  
e.printStackTrace (); dG\dGSZ\h  
} BTqY _9  
!CUrpr/*  
(k4>I"x)  
return n; Q! WXFS  
} J'W6NitMr  
B\`4TU}kE  
4vF1  
} UH2fP G  
rz5AIe>Hm  
Cjdw@v0;  
/* M"W-|t)~  
**SiteInfoBean.java _DS_AW}D  
*/ !{jDZ?z{h  
package NetFox; !;>j(xc  
Y<odXFIS  
M, f6UYo=  
public class SiteInfoBean { @-)jU!  
#f d ;]  
bejvw?)S.  
private String sSiteURL; //Site's URL _46 y  
private String sFilePath; //Saved File's Path 3U^E<H  
private String sFileName; //Saved File's Name Xf(H_&K  
private int nSplitter; //Count of Splited Downloading File qf-0 | w  
rZEL7{  
Dn1aaN6  
public SiteInfoBean() )ERmSWq/u  
{//nSplitter的缺省值为5 _NA[g:DZ&O  
//default value of nSplitter is 5 :+06M@  
this("","","",5); [f 4Nq \i  
} 7S|nn|\Kp  
7b7@"Zw*  
8Th{(J_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,t2Mur  
{ yy8h8{=g  
sSiteURL= sURL; ei%L[>N  
sFilePath = sPath; bLuAe EA  
sFileName = sName; WKek^TW4HE  
this.nSplitter = nSpiltter; >UlAae44  
/x\{cHAt8J  
 UDl[  
} ^VabXGzo#  
cgY + xd@  
-*HR0:H  
public String getSSiteURL() /{il;/Vj  
{ dz_~_|  
return sSiteURL; H}vq2|MN  
} SA!P:Q?h  
()%NotN;  
;&=c@>!xP#  
public void setSSiteURL(String value) vuN!7*d+  
{ :Aq==N_/2  
sSiteURL = value; 4E:kDl*@  
} NpqK+GO  
hUR>NUK@8  
_!_%Afz  
public String getSFilePath() apmZ&Ab  
{ +9yV'd>U  
return sFilePath; v@n0ma=  
} {5`=){  
DNwqi"  
@,kR<1  
public void setSFilePath(String value) )/Z% HBn  
{ PLoD^3uG)  
sFilePath = value; ]fiAV|'^  
} jxeZ,w o  
*e/8uFX  
9\ f%+?p  
public String getSFileName() pT ]:TRPS  
{ 'Sk-L 5  
return sFileName; _e4%<!1  
} ( &N`N1  
q#pD}Xe$  
#u]'3en  
public void setSFileName(String value) 3pU/Z bb,:  
{ {&3{_Ml  
sFileName = value; S1SsJo2\  
} 5|:t$  
4 s&9A/&pC  
(58}G2}q  
public int getNSplitter() $<DcbJW  
{ m6wrG`-di  
return nSplitter;  {@E(p4W  
} ^&8FwV]  
>tGl7Ov  
&-R(u}m-F  
public void setNSplitter(int nCount) 1>)q 5D  
{ 7j,u&%om  
nSplitter = nCount; 7^bde<0  
} J)I|Xot  
} R-[t 4BHn  
L@VIC|~E  
3]MSS\uB  
/* ']Z1nb  
**Utility.java Cr&,*lUo  
*/ =pa F6!AB  
package NetFox; R%EpF'[~[  
y*oH"]D  
Ng,< 4;  
public class Utility { qL;u59  
K (px-jY  
4arqlz lo  
public Utility() 5oOF|IYi  
{ I l2`c}9  
iCX Ki7  
RvXK?mL4F  
} vHmsS\\~9  
nGoQwKIW  
//线程睡眠 K3*8-Be  
public static void sleep(int nSecond) )y#~eYn  
{ ~[[(_C3  
try{ )\3 RR.p  
Thread.sleep(nSecond); J>w3>8!>7  
} `2I<V7SF$  
catch(Exception e) Z)qts=  
{ 9jkaEn>m^  
e.printStackTrace (); =sFLzAu8  
} (6g;FD:"6  
} f5tkv<) %  
F4X0DRC,G  
//日志 _DD.#YB</  
public static void log(String sMsg) G?$0OU  
{ EEI !pi  
System.err.println(sMsg); SSrYFu"  
} 8n2MZ9p]  
0pW?v:!H  
HzdyfZ!jR  
public static void log(int sMsg) qvHRP@  
{ Bj1{=Pvl  
System.err.println(sMsg); jT:z#B%  
} + 7~u_J  
} /$-Tg)o5i  
31*0b|Z  
.$]%gjIBCl  
/* I 7 B$X=  
**TestMethod.java xtq='s8e  
*/ t^')ST  
package NetFox; !Zi_4 .(4  
Z]^Ooy[pb  
UB9n7L(@c  
public class TestMethod { Ms61FmA4  
ZvVrbj&  
JlMD_pA  
public TestMethod() -F338J+J24  
{ ///xx/weblogic60b2_win.exe OL0W'C9oA  
try{ ibj3i7G?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]- +%]'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); S`t@L}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =" Sb>_  
fileFetch.start(); /9wmc2  
} 0Z,a3)jcc  
catch(Exception e){e.printStackTrace ();} )}|b6{{<  
vw5f|Q92  
l =`?Im  
} tgpg  
&ZR}Z7E*=  
V'Z Z4og  
public static void main(String[] args) uW{;@ 7N  
{ 9\J6G8b>|I  
new TestMethod(); @o/126(k  
} L0QF(:F5  
} [+8in\T i  
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