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http断点续传简单实现(java)

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/* Q Yg V[\&  
**SiteFileFetch.java jd`h)4  
*/ S=<OS2W7+r  
package NetFox; ~&< Ls  
import java.io.*; g@2KnzD  
import java.net.*; E1j3c :2  
9?iA~r|+  
5szJ.!(  
public class SiteFileFetch extends Thread { \ )WS^KR%  
$35C1"  
)b?$ 4<X^  
SiteInfoBean siteInfoBean = null; //文件信息Bean uv=a}U;  
long[] nStartPos; //开始位置 \Up~ "q>Kb  
long[] nEndPos; //结束位置 b4qMTRnv  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 YP Qix  
long nFileLength; //文件长度 S6g_$ Q7  
boolean bFirst = true; //是否第一次取文件 ?$K.*])e  
boolean bStop = false; //停止标志 YK\pV'&+  
File tmpFile; //文件下载的临时信息 j1rR3)oP  
DataOutputStream output; //输出到文件的输出流 q|{z9V<  
,!40\"A  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Z;<:=#  
public SiteFileFetch(SiteInfoBean bean) throws IOException KKq%'y)u^  
{ $cW t^B'  
siteInfoBean = bean; %*NED zy  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); -7KoR}Ck!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .?vHoNvo  
if(tmpFile.exists ()) 8y']kVg  
{ -UM|u_  
bFirst = false; zpD?5  
read_nPos(); k Nvb>v  
} bcq&yL'D  
else D;&\)  
{ G^sx/H76J  
nStartPos = new long[bean.getNSplitter()]; Xs{PAS0  
nEndPos = new long[bean.getNSplitter()]; _7z]zy@PC5  
} {O:{F?  
aGd wuD  
ur.krsU  
78\j  
} +[R^ ?~VK  
O{EPq' x  
h'HI92; [  
public void run() &) 64:l&  
{ &:&~[4>%a  
//获得文件长度 ,5V6=pr$  
//分割文件 %AN,cE*  
//实例FileSplitterFetch L+S)hgUH  
//启动FileSplitterFetch线程 #*q]^Is"  
//等待子线程返回 nG";?TT  
try{ ;\v&4+3S  
if(bFirst) Q*Y-@lZ  
{ ;mYZ@g%e  
nFileLength = getFileSize(); ^J&D)&"j  
if(nFileLength == -1) :C>iV+B j  
{ 2-DG6\QX|  
System.err.println("File Length is not known!"); x`c 7*q%  
} Gy[anDE&  
else if(nFileLength == -2) ] s^7c  
{ Rc:}%a%e  
System.err.println("File is not access!"); lu00@~rx/  
} "F}dZ  
else Wsgp#W+  
{ qw$9i.Z  
for(int i=0;i<nStartPos.length;i++) ]ag{sU@#  
{ Q5}XD  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); s1E 0atT  
} $E&T6=Wn  
for(int i=0;i<nEndPos.length-1;i++) 0%Le*C'yk  
{ c~4Cpy^  
nEndPos = nStartPos[i+1]; ZY8w1:'  
} tkH]_cH'w  
nEndPos[nEndPos.length-1] = nFileLength; g^Hf^%3xP  
} qTK(sW  
} %W8iC%~  
o">~ObR  
M(nzJ  
//启动子线程  ?HRS*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; "-djA,`  
for(int i=0;i<nStartPos.length;i++) Pro?xY$E)  
{ <5D4h!  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Xy%||\P{)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {Ef.wlZ  
nStartPos,nEndPos,i); ii_kgqT^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }LCm_av  
fileSplitterFetch.start(); 6}m`_d?  
} =^GPQ_"  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z\oTuW*B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); =}%#j0a4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "9r$*\wOf  
nEndPos = " + nFileLength); nShXY6bA  
// fileSplitterFetch[nPos.length-1].start(); pbEWnx_  
g<(!>:h  
0VcHz$ 6  
//等待子线程结束 l;KrFJ6  
//int count = 0; } A+ncabm  
//是否结束while循环 "T_9_6tH  
boolean breakWhile = false; a7c`[   
/='0W3+o*L  
U+*l!"O,  
while(!bStop) VsJ+-IHm  
{ 1Xo0(*O  
write_nPos(); (D%vN&F  
Utility.sleep(500); kmc_%Wm}  
breakWhile = true; ~h_ _Y>  
u.|%@  
\wD/TLS}  
for(int i=0;i<nStartPos.length;i++) CV\^gTPmx  
{ EYn?YiVFU  
if(!fileSplitterFetch.bDownOver) w$/lq~zU  
{ %-yzU/`JF  
breakWhile = false; ;  ?f+  
break; o S=!6h  
} 4VZI]3K,  
} , + G  
if(breakWhile) Nd]F 33|X  
break; CDM6o!ur3  
_\KFMe= PV  
Dc@O Mr  
//count++; COsmVQ.  
//if(count>4) d_d&su E  
// siteStop(); =TDKU  
} }< H>9iJ:  
r) x  
bwzx_F/  
System.err.println("文件下载结束!"); &muBSQ-  
} ':fp|m)M  
catch(Exception e){e.printStackTrace ();} 3nG.ah  
} +Ps.HW#NY  
WI4<2u;  
O_8 SlW0e  
//获得文件长度 'o6}g p)  
public long getFileSize() ",3v%$ >  
{ I{OizBom  
int nFileLength = -1; beBG40  
try{ aaig1#a@1b  
URL url = new URL(siteInfoBean.getSSiteURL()); u0Wt"d-=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <HoCt8>U  
httpConnection.setRequestProperty("User-Agent","NetFox"); l<w7 \a6  
F<k+>e  
TG}owG]]  
int responseCode=httpConnection.getResponseCode(); y62f{ks_/  
if(responseCode>=400) sJ|pR=g)!  
{ n!4\w>h  
processErrorCode(responseCode); yf9"Rc~+  
return -2; //-2 represent access is error ^T!Zz"/:  
} ,_u7@Ix  
 I8?  
Q__CW5&'u  
String sHeader; {ogBoDS  
gMI%!Y  
}yK7LooM  
for(int i=1;;i++) x6`mv8~9Db  
{ H P.=6bJWi  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); R>O_2`c  
//Utility.log(in.readLine()); H[u9C:}9b  
sHeader=httpConnection.getHeaderFieldKey(i); c'i5,\ #X  
if(sHeader!=null) gSwV:hm  
{ fgd2jr 3T  
if(sHeader.equals("Content-Length")) x|a&wC2,{  
{ VkFh(Br<{  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 4%J0e'iN  
break; ot<d FvD  
} p[JIH~nb  
} AOZ C D{  
else DLrV{8%W  
break; E xhih^[_  
} >`0U2K  
} \W .CHSD  
catch(IOException e){e.printStackTrace ();} zuLW'a6F-  
catch(Exception e){e.printStackTrace ();} K khuPBd2  
rNq* z,  
?Z 2,?G  
Utility.log(nFileLength); iSCkV2  
`-uE(qp  
^wolY0p  
return nFileLength; S/XU4i:aV  
} !G-+O#W`  
@}H u)HO  
;stuTj@vH  
//保存下载信息(文件指针位置) Ab ,^y  
private void write_nPos() nZbI}kcm  
{ oIE 1j?  
try{ :EV.nD7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $XhMI;h  
output.writeInt(nStartPos.length); 8X,6U_>#a  
for(int i=0;i<nStartPos.length;i++) ~pRgTXbz  
{ $(9QnH1KY  
// output.writeLong(nPos); .2f vRN92  
output.writeLong(fileSplitterFetch.nStartPos); 7<xnE]jdq  
output.writeLong(fileSplitterFetch.nEndPos); }qiZ%cT.G  
} %XG m\p  
output.close(); 5)RZJrN]  
} 309 pl  
catch(IOException e){e.printStackTrace ();} O6hzOyNX@  
catch(Exception e){e.printStackTrace ();} /xk7Z q  
} pJ] Ix *M  
0(7 IsG=t  
_p*9LsN$L  
//读取保存的下载信息(文件指针位置) I1fpX |  
private void read_nPos() j+_fHADq  
{ BX?DI-o^h  
try{ _iJ~O1qx,w  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 8z1z<\  
int nCount = input.readInt(); j9NF|  
nStartPos = new long[nCount]; b)I-do+  
nEndPos = new long[nCount]; 5*$yY-A  
for(int i=0;i<nStartPos.length;i++) O=2|'L'h!  
{ k4ti#3W5eG  
nStartPos = input.readLong(); Bz ;r<Kn  
nEndPos = input.readLong(); vUpAW[[  
} ^!1!l-  
input.close(); ">bhxXeiN  
} ZIx-mC5  
catch(IOException e){e.printStackTrace ();} P4[kW}R  
catch(Exception e){e.printStackTrace ();} >$ZG=&  
} oN1D&*  
l ;:IL\*1I  
}Z"iW/?"  
private void processErrorCode(int nErrorCode) -$Z1X_~;)<  
{ !rUP&DA  
System.err.println("Error Code : " + nErrorCode); 6YM X7G]  
} iqDyE*a  
}Ja-0v)Wf  
4`,(*igEv  
//停止文件下载 @)U.Dbm  
public void siteStop() U>PZ3  
{ kG>jb!e@(  
bStop = true; ;MS.ag#  
for(int i=0;i<nStartPos.length;i++) a#j,0FKv  
fileSplitterFetch.splitterStop(); IIR+qJ__|  
kZw"a*6  
Cb;6yE)!Z  
} AY/.vyS  
} ;R*-cm  
//负责部分文件的抓取 jaoZ}}V_$  
**FileSplitterFetch.java [Fr](&Tx  
*/ /w?e(v<  
package NetFox; KOy{?  
lMY\8eobcB  
'3>;8(s l  
import java.io.*; XKjrS 9:  
import java.net.*; Ljy797{f  
K{P-+(  
[9">}l  
public class FileSplitterFetch extends Thread { LIID(s!bX  
 ~71U s  
; JkSZs3  
String sURL; //File URL yzS^8,  
long nStartPos; //File Snippet Start Position =d{6=2Pt  
long nEndPos; //File Snippet End Position 4zMvHe  
int nThreadID; //Thread's ID [bh?p+V  
boolean bDownOver = false; //Downing is over 40kAGs>_  
boolean bStop = false; //Stop identical i6if\B  
FileAccessI fileAccessI = null; //File Access interface sq'm)g  
kOQ)QX  
I0}.!  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ukR0E4p  
{ XJ<"S p  
this.sURL = sURL; \L*%?~  
this.nStartPos = nStart; _w\9 \<%  
this.nEndPos = nEnd; 6(8 F4[D  
nThreadID = id; SxRJ{m~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 j[r}!;O  
} -$Fj-pO\  
J8:s=#5  
C7%R2>}?f  
public void run() HgQjw!  
{ !eyLh&]5  
while(nStartPos < nEndPos && !bStop) ;73S;IPR  
{ 2)=whnFS  
eGEwXza 4  
JqzoF}WH  
try{ rRe5Q  
URL url = new URL(sURL); f-F=!^.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +fVvH  
httpConnection.setRequestProperty("User-Agent","NetFox"); 1bV G%N  
String sProperty = "bytes="+nStartPos+"-"; D :@W*,  
httpConnection.setRequestProperty("RANGE",sProperty); #kW=|8X  
Utility.log(sProperty); +M=h+3hw](  
{>ba7-Cy+y  
{"wF;*U.V  
InputStream input = httpConnection.getInputStream(); ZG=]b%  
//logResponseHead(httpConnection); <X8Urum  
E22o-nI?1  
 :xsZz$  
byte[] b = new byte[1024]; `PUqz&  
int nRead; i-CJ{l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  V(&L  
{ *u$aItx  
nStartPos += fileAccessI.write(b,0,nRead); Dmh$@Uu#F  
//if(nThreadID == 1) 1mmL`M1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); -gs I:-Xo  
} o-8{C0>:  
gNZwD6GMe?  
3WwS+6R  
Utility.log("Thread " + nThreadID + " is over!"); Dge#e  
bDownOver = true; >6C\T@{lJ  
//nPos = fileAccessI.write (b,0,nRead); 5=TgOS]R  
} r8m}B#W7  
catch(Exception e){e.printStackTrace ();} a OmG,+o  
} t1Ts!Q2  
} d'_q9uf'  
f+:iz'b#U  
$J6 .0O  
//打印回应的头信息 pz^S3fy  
public void logResponseHead(HttpURLConnection con) 1clzDwW  
{ \n_7+[=E  
for(int i=1;;i++) ='"Yj  
{ L0![SE>  
String header=con.getHeaderFieldKey(i); [Hx}#Kds  
if(header!=null) !RKuEg4hQ  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Wet0qt]  
Utility.log(header+" : "+con.getHeaderField(header)); )?jFz'<r  
else 2* g2UP  
break; =Z+^n ?"  
} 2O kID WcM  
} !~E/Rp  
IOFXkpK R  
]xvA2!) Q  
public void splitterStop() I$"Z\c8;  
{ .F ?ww}2p]  
bStop = true; qJ;~ANwt  
} XIIq0I  
?A@y4<8R|  
q[Ai^79  
} aqSOC(jU  
oRbWqN`F.  
g]f<k2  
/* 29:2Xu i  
**FileAccess.java sPK]:i C  
*//文件访问(定位,写) 1sXCu|\q  
package NetFox; U 4d7-&U  
import java.io.*; dC6>&@ VX  
C@-Hm  
WoXAOj%iW  
public class FileAccessI implements Serializable{ +Ug &  
rai'x/Ut}+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 qK'mF#n0#  
RandomAccessFile oSavedFile; s`x2Go  
long nPos; e,s  S.  
#. Dl1L/  
k)knyEUi  
public FileAccessI() throws IOException t3$cX_  
{ 4<s;xSCL  
this("",0); \gP?uJ  
} +vZYuEq_  
4b}p[9k  
xiW}P% bf  
public FileAccessI(String sName,long nPos) throws IOException wQ(DX!   
{ Cx;it/8+  
oSavedFile = new RandomAccessFile(sName,"rw"); A6szTX#0  
this.nPos = nPos; }P2*MrkcHB  
oSavedFile.seek(nPos); 0-p^o A  
} Ow-ejo  
lz=DGm  
pKLcg"{[F  
public synchronized int write(byte[] b,int nStart,int nLen) W<<G  'Km  
{ ,q*|R O  
int n = -1; \WE/#To  
try{ 0faf4LzU!  
oSavedFile.write(b,nStart,nLen); NL.3qx  
n = nLen; ok--Jyhv#  
} I 6WHC*  
catch(IOException e) ;FlDRDZ%  
{ @IL@|Srs8  
e.printStackTrace (); y6am(ugE  
} Q8HNST($?  
0^{Tq0Ri[  
YEV;GFI1  
return n; 86%k2~L  
} q!&:y7O8  
N_D=j 6B  
}*XF- U  
}  mTH[*Y,  
(l][_6Q  
.NdsKhg b  
/* e`+  
**SiteInfoBean.java 6 w!qZ4$  
*/ ="T}mc  
package NetFox; -)J*(7F(6^  
tDAX pi(  
`LFT"qnp  
public class SiteInfoBean { a\-5tYo`u  
PM*lnd#J  
R?:K\  
private String sSiteURL; //Site's URL V,ZRX}O  
private String sFilePath; //Saved File's Path heF'7ezv#  
private String sFileName; //Saved File's Name -0(+a$P7e  
private int nSplitter; //Count of Splited Downloading File 2;:]Q.g  
(QFZM"G  
Z+R-}<   
public SiteInfoBean() #d8]cm=  
{//nSplitter的缺省值为5 >CCy2W^W  
//default value of nSplitter is 5 /_<_X 7  
this("","","",5); k5&}bj-  
} #5;4O{  
gd3MP^O1  
/ pe.?Zd  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &}gH!5L m  
{ fk^DkV^<  
sSiteURL= sURL; 3Mh_ &%!O  
sFilePath = sPath; o)\EfPT  
sFileName = sName; [Qkj}  
this.nSplitter = nSpiltter; Pd:tRY+t/  
CNiJuj`  
3rh t5n2-  
} 1b=\l/2  
:@~3wD[y  
_uh@fRyh  
public String getSSiteURL() Qm3 RXO  
{ W*c^(W  
return sSiteURL; 1%.CtTi  
} ~O;?;@  
%|}7YH41  
l5e`m^GK  
public void setSSiteURL(String value) IxG0TJ_  
{ Qe[ai?iJkt  
sSiteURL = value; k:s86q  
} n-9X<t|*?a  
DKQQZ` PF  
c1%ki%J#  
public String getSFilePath() <Dnv=)Rq  
{ G* mLb1  
return sFilePath; o,1Fzdh6(  
} uN9.U  _  
arPqVMVr  
:fG9p`  
public void setSFilePath(String value) 2\}6b4  
{ .dBW{|gN  
sFilePath = value; wW/wvC-  
} BGB.SN#q+  
9&c *%mm  
>GDN~'}^oz  
public String getSFileName() LrfyH"#!:  
{ QZ-6aq\sgp  
return sFileName; Rm.9`<Y  
} xI=[=;L  
#5kg3OO  
5o~AUo{  
public void setSFileName(String value) ``?Z97rH  
{ l&Fx< W  
sFileName = value; ~i@Z4t j7  
} (P:.@P~  
Jxb+NPUB  
~f2-%~  
public int getNSplitter() YsjTC$Tx,  
{ 1K$8F ~%Z  
return nSplitter; 47/YD y%  
} `WU"*HqW  
LTY(6we-  
S1$&  
public void setNSplitter(int nCount) V,9UOC,Gn  
{ BI)$aR  
nSplitter = nCount; ErMA$UkJ  
} rUF= uO(  
} 8>^O]5Wo`X  
_Ai\XS Am  
_1Iw"K49Qx  
/* nIP*yb}5  
**Utility.java Z"<tEOs/En  
*/ EEp,Z`  
package NetFox; ~_L_un.R  
G5x%:,n  
b!|c:mE9|  
public class Utility { [.iz<Yh  
oxm3R8 S  
hz+x)M`Y  
public Utility() OGO4~Up  
{ $5l=&  
T%:W6fH7  
~4tu*\P  
} j.rJfbE|X  
#$>m`r  
//线程睡眠 F0FF:><  
public static void sleep(int nSecond) a)8M'f_z  
{ hbdM}"&]  
try{ 0~XZ  
Thread.sleep(nSecond); SfwAMNCe  
} V5LzUg]  
catch(Exception e) wg,w;Gle  
{ <[GkhPfZ  
e.printStackTrace (); -i?-Xj#%  
} P\H$*6v(  
} VSt)~  
fL&bN[XA"$  
//日志 J4ltHk.|  
public static void log(String sMsg) |P]>[}mD  
{ v iY&D  
System.err.println(sMsg); MkG*6A  
} D@>^_cTO24  
`=3:*.T*  
4jl-?  
public static void log(int sMsg) `H6kC$^Ofx  
{ Lm}:`  
System.err.println(sMsg); 3"hPplE  
} * 7 o(  
} t/aT  
Bq]eNq  
x, ^j=n  
/* }A%Sx!7~  
**TestMethod.java *G#W],~0  
*/ 3Ga! )  
package NetFox; y\&`A:^[ A  
u>.qhtm[  
.qCD(XZ+  
public class TestMethod { /u 8m|S<  
>{^&;$G+*  
Rs cU=oaKi  
public TestMethod() 7x^P74  
{ ///xx/weblogic60b2_win.exe  u m[nz  
try{ Xo>P?^c4?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #yv_Eb02  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); AVA hS}*t  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tQ:)j^\  
fileFetch.start(); Ln})\ UDK)  
} xCMcS~ 3/  
catch(Exception e){e.printStackTrace ();} @4D$Xl  
t .&YD x  
y#Ao6Od6  
} L= fz:H  
4cni_m]  
8`*Wl;9u  
public static void main(String[] args) )FkJ=P0  
{ Og?]y ^y  
new TestMethod(); /bj D*rj  
} K -!YD}OF  
} XOzd{  
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