http断点续传简单实现（java)

/* (=,p"3^  
**SiteFileFetch.java j'
g':U  
*/ > -OQk"o  
package NetFox; #}3$n/  
import java.io.*; WbB0{s  
import java.net.*; +Ccj@#M;  
6"b =aPTi  
@#xh)"}  
public class SiteFileFetch extends Thread { A46Xei:Ow  
f 0D9Mp  
@|sDb?J  
SiteInfoBean siteInfoBean = null; //文件信息Bean [kaj8  
long[] nStartPos; //开始位置 r$<[`L+6  
long[] nEndPos; //结束位置 %i:Sf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 rjHL06qE  
long nFileLength; //文件长度 eKsc ["  
boolean bFirst = true; //是否第一次取文件 PQDWY
 
boolean bStop = false; //停止标志 l.Iov?e1S  
File tmpFile; //文件下载的临时信息 |hk?'WGc`0  
DataOutputStream output; //输出到文件的输出流 gq\ulLyOeZ  
<KlG#7M>  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） eX;C.[&7;8  
public SiteFileFetch(SiteInfoBean bean) throws IOException CvS}U%  
{ Ksr.'  
siteInfoBean = bean; ;rC)*=4#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); NBU[>P  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \$LrL  
if(tmpFile.exists ()) 80DcM9^t8  
{ S2T~7-  
bFirst = false; &;I=*B~kE$  
read_nPos(); 4Hc+F(  
} q$7SJ.pF  
else R9%Um6  
{ ~`~mnlN  
nStartPos = new long[bean.getNSplitter()]; ))JbROBU,  
nEndPos = new long[bean.getNSplitter()]; ~\<aj(m(|  
} 7#wdBB%  
kqdF)Wa am  
kwF4I)6  
1w*DU
9f  
} h2<Y*j  
JL.noV3q$  
=wE1j  
public void run() qn=~4rg]R  
{ I*hCIy#;  
//获得文件长度 g:V8"'  
//分割文件 ]rU$0)VN  
//实例FileSplitterFetch aAJ'0xnj  
//启动FileSplitterFetch线程 JO{Rth  
//等待子线程返回 WCJ$S\#  
try{ {kVhht]X  
if(bFirst) S&N[@G  
{ W(.q.Sx>  
nFileLength = getFileSize(); >..C^8 "  
if(nFileLength == -1) m$

6u K0  
{ AM?62  
System.err.println("File Length is not known!"); `0'Bg2'  
} 2vbm=~)$F  
else if(nFileLength == -2) 7S'3U}Y>VX  
{ cG{>[
Lf  
System.err.println("File is not access!"); NFxs4:] RT  
} ~ A?  
else
w&VMb&<  
{ cVk&Yp;[*  
for(int i=0;i<nStartPos.length;i++) _ljdo`j#N  
{ nZ7FG  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); C5k\RS9  
} 1VRexp  
for(int i=0;i<nEndPos.length-1;i++) vOMmsU F  
{ Bg3`w__l;  
nEndPos = nStartPos[i+1]; ,j^z];  
} ! 3&_#VO  
nEndPos[nEndPos.length-1] = nFileLength; afE`GG-  
} *|97 g*G(  
} fjGYp  
J)yNp,V  
/8](M5X]f  
//启动子线程 5BWO7F0v"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; GBMCw  
for(int i=0;i<nStartPos.length;i++) SI-G7e)3;>  
{ H!uB&qY  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r92C^h0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @-9u;aL  
nStartPos,nEndPos,i); HH`G/(a  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); (rDB|kc^7  
fileSplitterFetch.start(); >U?U;i  
} rwYlg:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sA!
,)'6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >M1m(u84#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @!;EW R]  
nEndPos = " + nFileLength); ,AX7~;hpq  
// fileSplitterFetch[nPos.length-1].start(); I"AgRa  
.@7J8FS*  
0qND2_  
//等待子线程结束 ~x}/>-d  
//int count = 0; q].n1w[  
//是否结束while循环 &tKr ?l  
boolean breakWhile = false; ~D[5AXV`^  
? dD<KCbP,  
UM?{ba9  
while(!bStop) C
Y{`IZ  
{ 4&TTPcSt;  
write_nPos(); !4gyrNS  
Utility.sleep(500); )+!~xL  
breakWhile = true; /<J&ZoeJB  
qhNY<  
r@j$$Pk`  
for(int i=0;i<nStartPos.length;i++) d`M]>EDXp  
{ DH@})TN*O  
if(!fileSplitterFetch.bDownOver) RfM uWo:  
{ -&3WN!egq  
breakWhile = false; ?$:;hGO.<~  
break; 7F=Xn@ _  
} ^&nC)T<w  
} : 5=E>!  
if(breakWhile) e7fA-,DV  
break; Sw<V/t  
s*blZdP  
Mwm=r//  
//count++; _9@D o6  
//if(count>4) ?hW?w$C  
// siteStop(); 7hQf T76h  
} f(Hh(  
>%vw(pt  
Woo2hg-ti  
System.err.println("文件下载结束！"); lz=DP:/&  
} 7.G1Q]6/  
catch(Exception e){e.printStackTrace ();} f{]eb1  
} GoVB
1)  
G'*_7HD  
zP[_ccW@  
//获得文件长度 [8T  
public long getFileSize() fa~u<m  
{ d~lB4  
int nFileLength = -1; eh@6trzp=  
try{ b7X-mkF  
URL url = new URL(siteInfoBean.getSSiteURL()); YJioR4+q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *""JE'wG  
httpConnection.setRequestProperty("User-Agent","NetFox"); q;Y9_5S  
CTqAhL 4}  
K]0Q=HY{.  
int responseCode=httpConnection.getResponseCode(); Y+ZQN>  
if(responseCode>=400) W6kDQ&q  
{ vSu|!Xb]  
processErrorCode(responseCode); %]~XbO  
return -2; //-2 represent access is error K2=`.  
} v
Xdz?  
I(i/|S&^  
i{['18Q$F3  
String sHeader; V
!Cu%4  
z0XH`H|~  
pP1|/f5n`  
for(int i=1;;i++) TB=KTj  
{ 
T?p'R  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); "K.XoG4|  
//Utility.log(in.readLine()); sn|q EH  
sHeader=httpConnection.getHeaderFieldKey(i); qNhV zx  
if(sHeader!=null) !^o(?1  
{ 6##}zfl  
if(sHeader.equals("Content-Length")) D4CN%^?  
{ >g):xi3qK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); +Lq;0tRC  
break; VxlK:*t`  
} 994  
} ."N`X\  
else KJ7[DN'(  
break; me-:A:si  
} A7{l60(5  
} t}Z*2=DO  
catch(IOException e){e.printStackTrace ();} HwE1cOT  
catch(Exception e){e.printStackTrace ();} r*-e~  

H9c  

}~8/
a3  
Utility.log(nFileLength); nG0Uv%?{pj  
c&A;0**K,  
/EJwO3MW  
return nFileLength;
(IAc*V~  
} 0SoU\/kUi  
W{0gtT0  
=y5~7&9'  
//保存下载信息（文件指针位置） V}leEf2'  
private void write_nPos() cfb8kNn~+  
{ XM0;cF  
try{ n?@3+wG  
output = new DataOutputStream(new FileOutputStream(tmpFile)); UfE41
el:  
output.writeInt(nStartPos.length); f zu#!  
for(int i=0;i<nStartPos.length;i++) q&eUw<(F  
{ 9u3~s<  
// output.writeLong(nPos); EYe)d+E*  
output.writeLong(fileSplitterFetch.nStartPos); 2TR l@  
output.writeLong(fileSplitterFetch.nEndPos); &4aY5y`8+f  
} qr5ME/)z  
output.close(); hq5=>p  
} Ihe/P {t]J  
catch(IOException e){e.printStackTrace ();} /+FZDRf!r  
catch(Exception e){e.printStackTrace ();} ZI<p%IQ  
} W*'gqwM&  
R~z@voM*<  
m,zZe}oJ  
//读取保存的下载信息（文件指针位置） o_2mSD
!  
private void read_nPos() }]-SAM  
{ ?[[K6v}q{  
try{ 4JF8S
#8B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ri,8rf0u
 
int nCount = input.readInt(); IIN"'7Z^R  
nStartPos = new long[nCount]; M6ol/.G[  
nEndPos = new long[nCount]; *`}4]OGv.  
for(int i=0;i<nStartPos.length;i++) 6Y#-5oEu/  
{ Vrz6<c-'B  
nStartPos = input.readLong(); Q77iMb]  
nEndPos = input.readLong(); NW}kvZ  
} 
YNGG> ;L  
input.close(); Sa V]6/|  
} >s@6rNgf  
catch(IOException e){e.printStackTrace ();} Cm4$&?  
catch(Exception e){e.printStackTrace ();} X%S9H^9  
} yIS.'mK  
;l]OmcL  
P,S$qD*4  
private void processErrorCode(int nErrorCode) /o<tmK_m  
{ ObDcNq/b!  
System.err.println("Error Code : " + nErrorCode); l)PEg PSRV  
} +6vm4(3?  
uUAib<wdPL  
~=t,g S  
//停止文件下载 7\'ow|)}v  
public void siteStop() IN? A`A  
{ O*af`J{  
bStop = true; -j%!p^2j9  
for(int i=0;i<nStartPos.length;i++) ]jWe']T  
fileSplitterFetch.splitterStop(); !}sYPz]7!  
OL{U^uOh
Y  
m6qmZ2<  
} X X>Y]P a  
} l}>gG[q!  
//负责部分文件的抓取 /2,s-^  
**FileSplitterFetch.java sje}E+{[  
*/  E%g_O_  
package NetFox; >\Qyg>Md]  
cmQLkT"#K  
JwzA'[tM  
import java.io.*; w%,Iy,G@  
import java.net.*; 05".;(  
]xf lfZ  
7y",%WYSD  
public class FileSplitterFetch extends Thread { Qtmsk:qm  
MSPzOJQPy  
K5x&:z  
String sURL; //File URL >w:px$g4  
long nStartPos; //File Snippet Start Position ziuhS4k  
long nEndPos; //File Snippet End Position H'uRgBjWJ  
int nThreadID; //Thread's ID 0T!_;IQ  
boolean bDownOver = false; //Downing is over u7!X#<  
boolean bStop = false; //Stop identical e_6@oh2s-  
FileAccessI fileAccessI = null; //File Access interface Ez^U1KKOE7  
/*Z,i&eC  
xbex6i"ZE  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )j6VROt  
{ DUg  
this.sURL = sURL; ffGiNXCM  
this.nStartPos = nStart; Sqw.p#  
this.nEndPos = nEnd; 4|fI9.  
nThreadID = id; Rv=(D^F,  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 N|eus3\E  
} .M_[tl  
CT6Ca,  
S#{e@ C  
public void run() M%f96XUM  
{ \WD}@6) ~  
while(nStartPos < nEndPos && !bStop) <C\snB  
{ /H+j6*}r  
a;AvY O  
}Vw"7  
try{ IfoeHAWX  
URL url = new URL(sURL); BH0@WG7F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \AOVdnM:  
httpConnection.setRequestProperty("User-Agent","NetFox"); vJkY  
String sProperty = "bytes="+nStartPos+"-"; dBY,&=T
4p  
httpConnection.setRequestProperty("RANGE",sProperty); l -~HY*  
Utility.log(sProperty); y\Z7]LHCqw  
#RK?3?wcr  
|+//pGx  
InputStream input = httpConnection.getInputStream(); X}`|"NIk.  
//logResponseHead(httpConnection); %n`wU-?lK  
k<uC[)_  
sfez0Uqe.~  
byte[] b = new byte[1024]; vukI`(#  
int nRead; @bdGV#*d  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /jih;J|  
{ #SQao;>  
nStartPos += fileAccessI.write(b,0,nRead); U7U-H\t7  
//if(nThreadID == 1) lmb5Z-xB  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); qp>O#tj[  
} |yiM7U,i  
t&(}`W  
C|c'V-f  
Utility.log("Thread " + nThreadID + " is over!"); d^X;XVAvP  
bDownOver = true; h^ ex?  
//nPos = fileAccessI.write (b,0,nRead); DPn]de:e  
} 2.O
;  
catch(Exception e){e.printStackTrace ();} i'|rx2]e  
} xtL_,ug  
} Z
^9;sb,x  
:
(,uaX>{  
ny17(Y =  
//打印回应的头信息 xd\k;nq  
public void logResponseHead(HttpURLConnection con) JB(~O`  
{ +\G/j]3f  
for(int i=1;;i++) uW!',"0ER  
{ P:&XtpP  
String header=con.getHeaderFieldKey(i); |4BS\fx~N  
if(header!=null) W:8_S%~d  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); P6*IR|  
Utility.log(header+" : "+con.getHeaderField(header)); $6 \v1
 
else %qR
bl4  
break; Sf[ZGY)  
} ,EW-21  
} HjKj.f
V  
zC6,m6Dv  
:.6kXX'~  
public void splitterStop() ^2OBc  
{ 0EfM~u  
bStop = true; wI\v5&X-B  
} bb[.Kvq5  
E$m3Gg)s>N  
FQ>KbZ
h  
} qczGv2%!  
"NSm2RU3  
TYW$=p|  
/* ext`%$ U7  
**FileAccess.java l'T3RC,\  
*//文件访问(定位，写) oEvXZ;F@.  
package NetFox; !'(bwbd  
import java.io.*; a5C%OI<  
J3cbDE%^m  
k$?zh$  
public class FileAccessI implements Serializable{ vK)^;
T ;  
DSad[>Uj],  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 W4
Nbl  
RandomAccessFile oSavedFile; @ae;&  
long nPos; <SmXMruU  
;1^_.3  
g76l@QYIU  
public FileAccessI() throws IOException 54s+4R FL  
{ $J&wwP[  
this("",0); "WR)a`$UR  
}  M]:4X_  
>t')ZSjRs  
:<f7;.  
public FileAccessI(String sName,long nPos) throws IOException K?:rrd=7q  
{ ST1PSuC~  
oSavedFile = new RandomAccessFile(sName,"rw"); _x_om#~n  
this.nPos = nPos; EaGh`*"w(7  
oSavedFile.seek(nPos); 5hak'#2  
} -S\7
4hA  
jd
iFb~5R  
B'>(kZYMs  
public synchronized int write(byte[] b,int nStart,int nLen) Q9=vgOW+  
{ j+NOT`&  
int n = -1; ((F[]<?  
try{ 1?sR1du,  
oSavedFile.write(b,nStart,nLen); hK*:pf  
n = nLen; B;?)   
} 1\t}pGSOeh  
catch(IOException e) KW|X\1H  
{ )3PQ|r'  
e.printStackTrace (); xTNWT_d  
}
#n5q$  
k/hE68<6i  
CS2AKa@`  
return n; qwJe
eax  
} 0G?0 Bo  
/H&:  
)MqF~[k<-  
} B]~#+rMK  
?kvkkycI  

#R v&b@K  
/* lx,^Y647  
**SiteInfoBean.java &*iar+vr  
*/ "mr;!"LA  
package NetFox; #!0le:_  
\TqKm  
T(%U$ea-S  
public class SiteInfoBean { 289teU  
n.P$7%G`2  
{t`UV,  
private String sSiteURL; //Site's URL (cJb/|?3  
private String sFilePath; //Saved File's Path GY 4?}T^s  
private String sFileName; //Saved File's Name f@&C \  
private int nSplitter; //Count of Splited Downloading File ZOvMA]Rf  
X+"8yZz3?  
6U)Lhf\'o  
public SiteInfoBean() "MZj}}l  
{//nSplitter的缺省值为5 ;Q>(%"z};  
//default value of nSplitter is 5 m:A7*r[  
this("","","",5); tgEXX-{  
} -_BS!T%r  
6O2
r5F$T  
{FyGh */  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) nsk`nck  
{ Tx"}]AyB6  
sSiteURL= sURL; <Okk;rj2  
sFilePath = sPath; <_&tP=h  
sFileName = sName; wZN<Og+;  
this.nSplitter = nSpiltter; lSU&Yqx  
~t\Hb8o  
rf1Us2vp  
} K~8;wDN`b  
]Ija,C!#  
r#LoBfM;^A  
public String getSSiteURL() . fq[>zG'&  
{ Ga0= G&/  
return sSiteURL; #"% ]1={b  
} \Ku6gEy  
C=2"*>lTn  
4Sv&iQ=vh  
public void setSSiteURL(String value) Z[:fqvXQ  
{ s8iJl+Jm  
sSiteURL = value;
L>Bf}^  
} r2H_)Oi  
~$} `R=  
:{<( )gfk  
public String getSFilePath() )? WiO}"  
{ OLpE0gZ.|`  
return sFilePath; v`8dRVN  
} y)_T!&ze  
Pda(O;aNU  
&A>Hq/Y  
public void setSFilePath(String value) PW)XDo7  
{ vhiP8DQ  
sFilePath = value; aR30wxW&)  
} f;M7y:A8q,  
m5Gt8Z 6a  
#UGm/4C  
public String getSFileName() RkP g&R;i  
{ zOkUR9  
return sFileName; tj@IrwC^e"  
} 5at\!17TY  
uTY5.8  
.hW_P62\#  
public void setSFileName(String value) A|p O  
{ 1
L.H"  
sFileName = value; @A6P[r  
} %9hzz5#  
[|<2BQX  
RGy4p)z*+  
public int getNSplitter() }|>mR];  
{ l?E7'OEF:  
return nSplitter; g@]G [(  
} +4U?*:n  
T.nY>Q8  
{X$8yy2zC5  
public void setNSplitter(int nCount) :{NvBxc[  
{ t.B%7e  
nSplitter = nCount; G\3@QgyQ  
} A\J|eSG'$  
} En%PIkxeR  
]h8[b9$<")  
$r})j
~c  
/* r<4FF=  
**Utility.java +BcJHNIB  
*/ v#i,pBj  
package NetFox; 2OFrv=F  
Ym IVtQ  
XUeBK/aQ{  
public class Utility { g}nlb.b]{m  
LO
{{3No  
w7}m T3p,)  
public Utility() ]&%_Fpx  
{ C8i6ESmU  
1B+uv0lA  
$OU,| D  
} td{M%D,R"  
 9')  
//线程睡眠 :X7"fX  
public static void sleep(int nSecond) D>wq4u  
{ t~m >\(&  
try{ V"=(I'X
 
Thread.sleep(nSecond); G/ToiUY  
} ??Zh$^No:  
catch(Exception e) Z>1\|j  
{ U6V+jD}L]  
e.printStackTrace (); ``bIqY  
} 9A0wiKp  
} I_66q7U"0  
?u`+?"'H  
//日志 Tvf%'%h1  
public static void log(String sMsg) W9>q1  
{ L h"K"Uv  
System.err.println(sMsg); YI!ecx%/4  
} & yFS  
 meQ>mW  
Kp[
 F@A#  
public static void log(int sMsg) Ul#||B .c{  
{ <RzGxhT  
System.err.println(sMsg); eZ+pZq  
} n<47#-  
} Bu4J8eLx  
PScq-*^  
t.'|[pOV  
/* |E:q!4?0  
**TestMethod.java #;ezMRKM"  
*/ =@w,D.5h  
package NetFox; Yg_;Eu0'?  
tNf?pV77  
f S-(Kmh  
public class TestMethod { >D20f<w(H  
$|~YXH~O  
f?)BAah  
public TestMethod() y>}dKbCN  
{ ///xx/weblogic60b2_win.exe 8!87p?Mz  
try{ R_iQLBr
d  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); f4F13n_0X  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6^ UQ{P1;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); owYf1=G  
fileFetch.start(); +dd\_\  
} B?d^JWTZ  
catch(Exception e){e.printStackTrace ();} R:49Gn:F  
HmxA2 ~C  
$RA8U:Q!1e  
} 
Nm;(M=  
Hrb67a%b  
w7d(|`  
public static void main(String[] args) CMk0(sztU_  
{ Y"J' 'K  
new TestMethod(); q)S70M_1  
} x;d*?69f]  
} Uu
Ds  
点击下载更多相关资料