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http断点续传简单实现(java)

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/* a &tWMxBr  
**SiteFileFetch.java }aOqoi7w  
*/ ( K[e=0Rf  
package NetFox; F%V|Aa  
import java.io.*; Ct'tUF<K5  
import java.net.*; +Kgl/Wg%  
y CHOg  
K{d3)lVYCS  
public class SiteFileFetch extends Thread { pT=^o  
#U-y<[ 3  
'TYO-'aC  
SiteInfoBean siteInfoBean = null; //文件信息Bean ';G/,wB?`  
long[] nStartPos; //开始位置 bqH [-mu6  
long[] nEndPos; //结束位置 ~0,v Q   
FileSplitterFetch[] fileSplitterFetch; //子线程对象 At@0G\^  
long nFileLength; //文件长度 8Ze> hEG  
boolean bFirst = true; //是否第一次取文件 0y$VPgsKf  
boolean bStop = false; //停止标志 P?q HzNGi7  
File tmpFile; //文件下载的临时信息 fK:4jl-r  
DataOutputStream output; //输出到文件的输出流 ~U w<e~  
CE M4E  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) s 4rva G@a  
public SiteFileFetch(SiteInfoBean bean) throws IOException (LsVd2AbR  
{ tC'#dU`=qY  
siteInfoBean = bean; q+[ )i6!?  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "<|KR{/+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); I._ A  
if(tmpFile.exists ()) jS]Saqd  
{ 346 z`5  
bFirst = false; lrc%GU):  
read_nPos(); 7Wef[N\x  
} s2L]H  
else V_ (Ly8"1;  
{ >&HW6 c  
nStartPos = new long[bean.getNSplitter()]; d s`YVXKH  
nEndPos = new long[bean.getNSplitter()]; ~H#c-B  
} }],l m  
U{dK8~  
e,#w* |  
>A{e,&  
} [<i3l'V/[  
N'{Yhx u  
o,j_eheAM  
public void run() &(<>} r  
{ ]4B;M Ym*  
//获得文件长度 a9&[Qv5-/  
//分割文件 8r>\scS  
//实例FileSplitterFetch O: I]v@  
//启动FileSplitterFetch线程 /*gs]  
//等待子线程返回 3VU4E|s>  
try{ i<m) s$u  
if(bFirst) ;fV"5H)U\  
{ h)sT37  
nFileLength = getFileSize(); YL`MLt4MC  
if(nFileLength == -1) 6{d?3Jk  
{ FnVW%fh  
System.err.println("File Length is not known!"); FLJ&ZU=s  
} u0) O Fz  
else if(nFileLength == -2) uB\UIz)e  
{ % dFz[b  
System.err.println("File is not access!"); z z]~IxQ  
} 8=bn TJf  
else :icpPv  
{ f.` 8vaV  
for(int i=0;i<nStartPos.length;i++) vD2(M1Q  
{ hc$m1lLn  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ox<6qW  
} 7gLk~*  
for(int i=0;i<nEndPos.length-1;i++) c{`!$Z'k<  
{ [x?9< #T  
nEndPos = nStartPos[i+1]; 4D 5Wse  
} 3qGz(6w6E  
nEndPos[nEndPos.length-1] = nFileLength; q%bFR[p<*  
} C3.]dsv:  
}  [A,!3BN  
<%^WZ:c  
})8D3kzX)  
//启动子线程 VxOWv8}|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %qJgtu"8  
for(int i=0;i<nStartPos.length;i++) |j/Y#.k;{0  
{  0zr%8Q(Q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F~fN7<9R  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), M-;Mw Lx  
nStartPos,nEndPos,i); AEf[:]i]  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G]xYQ]  
fileSplitterFetch.start(); f3vl=EA4|  
} vx6lud0k}  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t~}c"|<t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ADxje%!1O  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ]n@T5*=  
nEndPos = " + nFileLength); ?FS0zc!+  
// fileSplitterFetch[nPos.length-1].start(); {{bwmNv"  
,6^Xn=o #  
|gk4X%o6  
//等待子线程结束 uZf 6W<a  
//int count = 0; p4\sKF8-  
//是否结束while循环 r4K_Wp  
boolean breakWhile = false; 9;n*u9<  
Uv?^qe0=  
G{|"WaKW  
while(!bStop) K)1Lg? j  
{ ' 8R5 Tl  
write_nPos(); o3GZcH?  
Utility.sleep(500); 39[ylR|\  
breakWhile = true; SH"<f_  
M d Eds|D  
5D-as9k*  
for(int i=0;i<nStartPos.length;i++) 2!9W:I7  
{ :%28*fl  
if(!fileSplitterFetch.bDownOver) y_Gs_xg  
{ A#Ga!a  
breakWhile = false; <AJRU l  
break; N*PJ m6-  
} W4#DeT  
} 0%|)=T3Slu  
if(breakWhile) 1NTx?JJfW  
break; PxWH)4  
@qWClr{`  
7^@ 1cA=S  
//count++; gQ{<2u  
//if(count>4) "9X(.v0ze  
// siteStop(); zLxuxf~4@  
} C>-}BeY!  
a>6M{C@pd  
]f`UflMO8  
System.err.println("文件下载结束!"); iYdg1  
} "-5FUKI-  
catch(Exception e){e.printStackTrace ();} c/F!cW{z^  
} ^[+2P?^K  
%k"hzjXAw  
9N2.:<so  
//获得文件长度 vUL@i'0&o  
public long getFileSize() ,s}7KE  
{ x a\~(B.  
int nFileLength = -1; %Zfh6Bl\X  
try{ t82*rC IB{  
URL url = new URL(siteInfoBean.getSSiteURL()); XCgC^c'  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y+7+({w<  
httpConnection.setRequestProperty("User-Agent","NetFox"); V sL*&Fk  
,#^2t_c/  
TL -AL tG  
int responseCode=httpConnection.getResponseCode(); V.+a}J=Cw  
if(responseCode>=400) *uxKI:rB:  
{ 'Vhnio;qC  
processErrorCode(responseCode); R(}!gv}s  
return -2; //-2 represent access is error wk=s3^  
} hy~KY6Ta  
v9gaRqi8  
@te}Asv  
String sHeader; wSALK)T1{  
k<o<!   
^R+CkF4l l  
for(int i=1;;i++) K|;L{[[yH  
{ 6hFs{P7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); t?;=\%^<  
//Utility.log(in.readLine()); mndEB!b  
sHeader=httpConnection.getHeaderFieldKey(i); 6Tq2WZ}<'  
if(sHeader!=null) Ghe@m6|D  
{ rdX;  
if(sHeader.equals("Content-Length")) <rU+{&FKNL  
{ $ Fy)+<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); COH.`Tv{*  
break; )1)&fN41i#  
} LG?b]'#  
} !_&;#j](  
else CF+:v(NL  
break; K$$%j"s  
} Xs2B:`,hh  
} |c2;`T#`o  
catch(IOException e){e.printStackTrace ();} u^L_X A  
catch(Exception e){e.printStackTrace ();} Wl,I%<&j}  
^<aj~0v  
OJ7y  
Utility.log(nFileLength); 2\Yv;J+;  
`ih#>i_ &  
25;`yB$  
return nFileLength; .4=A:9  
} ]/mRMm9"3h  
Sh<A936/E  
Bf,}mCq  
//保存下载信息(文件指针位置) z+?48 }  
private void write_nPos() HDhG1B"NL  
{ 9H%ixBnM  
try{ T zHR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Wk/Il^YG  
output.writeInt(nStartPos.length); t\ 9Y)d  
for(int i=0;i<nStartPos.length;i++) 7{[i)  
{ KeC&a=HL  
// output.writeLong(nPos); mldY/;-H!1  
output.writeLong(fileSplitterFetch.nStartPos); _b[Pk;8}j;  
output.writeLong(fileSplitterFetch.nEndPos); 3cFvS[JG  
} sDy~<$l?  
output.close(); pzDz@lAwR  
} S|B S;VY  
catch(IOException e){e.printStackTrace ();} +AOpB L'  
catch(Exception e){e.printStackTrace ();} T"Nnl(cO_  
} 5=.mg6:  
S`[r]msw  
\j vS`+  
//读取保存的下载信息(文件指针位置) bB.Yq3KI  
private void read_nPos() ~rbJtz  
{ sO&eV68 [  
try{ Mwd.S  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); M3q7{w*bM  
int nCount = input.readInt(); N*Xl0m(Q  
nStartPos = new long[nCount]; /.m}y$@GV  
nEndPos = new long[nCount]; zvbz3a  
for(int i=0;i<nStartPos.length;i++) E._/PB  
{ AyMbwCR"X  
nStartPos = input.readLong(); aDX4}`u  
nEndPos = input.readLong(); <kWNx.eci  
} 3;EBKGg|  
input.close(); V5d|Lpm  
} JU-eoB}m  
catch(IOException e){e.printStackTrace ();} z-h7v5i"  
catch(Exception e){e.printStackTrace ();} x>[ gShAV!  
} #r80FVwiD  
;DI"9  
-k@Uo(MB  
private void processErrorCode(int nErrorCode) "I45=nf  
{ 6E:5w9_=c  
System.err.println("Error Code : " + nErrorCode); VD2o#.7*eu  
} [N*`3UZk"  
`qr.@0whP  
wRE2rsXoU  
//停止文件下载 !Y]%U @4}  
public void siteStop() jD_B&MQz  
{ Y/34~lhyl  
bStop = true; Z-z(SKL  
for(int i=0;i<nStartPos.length;i++) VI^~I;M^  
fileSplitterFetch.splitterStop(); c}#(,<8X  
{Gr"oO`&"  
q3Y49d  
} VDPq3`$+v{  
} 5~SBZYI  
//负责部分文件的抓取 O9MBQNwjA  
**FileSplitterFetch.java ~DK=&hCd!  
*/ SCD;(I~4  
package NetFox; C= PV-Ul+  
hUMFfc ?  
q|R$A8)L.  
import java.io.*; uWerC?da  
import java.net.*; 0XrOOYmx  
=zKbvwe%X  
lyrwm{&  
public class FileSplitterFetch extends Thread { K/XUF#^B]  
bR|1* <  
'd|E>8fejG  
String sURL; //File URL Ty"=3AvRLV  
long nStartPos; //File Snippet Start Position :Nw7!fd  
long nEndPos; //File Snippet End Position 4 {3< `  
int nThreadID; //Thread's ID fm^)u"  
boolean bDownOver = false; //Downing is over jQ\/R~)O  
boolean bStop = false; //Stop identical >oc&hT  
FileAccessI fileAccessI = null; //File Access interface wi-{&  
aOo;~u2-=  
kn7Qvk[+  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 7)+%;|~  
{ {_*$X  
this.sURL = sURL; ZlsdO.G  
this.nStartPos = nStart; G@]|/kN1y  
this.nEndPos = nEnd; v_ W03\  
nThreadID = id; t%>x}b"2T  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;Ajy54}7  
} Ol. rjz9  
&>o?0A6  
vH9Gf  
public void run()  al:c2o  
{ x<e-%HB*-  
while(nStartPos < nEndPos && !bStop) 9k>=y n  
{ wa4(tM2  
H(Q|qckj  
H) &pay  
try{ ;Cqjg.wkB  
URL url = new URL(sURL); vxC,8Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); t#[u X?  
httpConnection.setRequestProperty("User-Agent","NetFox"); hV4B?##O  
String sProperty = "bytes="+nStartPos+"-"; *Ad7GG1/u  
httpConnection.setRequestProperty("RANGE",sProperty); P(BV J_n  
Utility.log(sProperty); = g)G!  
P&@[ j0  
0Ku%9wh-  
InputStream input = httpConnection.getInputStream(); Ev;ocb,  
//logResponseHead(httpConnection); 5Pl~du  
~h*p A8^L  
IW'2+EGc  
byte[] b = new byte[1024]; )\TI^%s  
int nRead; )vFZl]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #GHLF  
{ q#~]Hp=W5  
nStartPos += fileAccessI.write(b,0,nRead); 2x*C1   
//if(nThreadID == 1) /y"Y o  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gZr/Dfy  
} 1$Pn;jg:  
|O]oX[~  
MrA&xM  
Utility.log("Thread " + nThreadID + " is over!"); Y)I8(g}0  
bDownOver = true; $yx34=  
//nPos = fileAccessI.write (b,0,nRead); wB;'+d&  
} H19CVc\B  
catch(Exception e){e.printStackTrace ();} txwTJScg  
} 4;ig5'U,  
} d>Z{TFY  
1=t\|Th-  
RZ[r XV5  
//打印回应的头信息 #?z 1cgCg  
public void logResponseHead(HttpURLConnection con) ,{{uRs/  
{ vx\h Njb  
for(int i=1;;i++) i%~4>k  
{ +0O{"XM  
String header=con.getHeaderFieldKey(i); 4JHFn [%  
if(header!=null) \8!&X cA  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2Ax HhD.  
Utility.log(header+" : "+con.getHeaderField(header)); ?7cF_Zvve  
else {Z_Pry$6  
break; D>O{>;y[  
} o " x& F  
} M,Px.@tw.  
?6 "F.\ O@  
UP]J `\$o  
public void splitterStop() mdOF0b%-]  
{ +*Cg2`  
bStop = true; K`@GN T&  
} q*ZjOqj  
1px:(8]{  
E$FXs~a  
} qb ^4G  
Z<|ca T]Q(  
qfY.X&]PU  
/* U"xI1fg%b  
**FileAccess.java A]{8 =  
*//文件访问(定位,写) 'B"kUh%3$5  
package NetFox; X./4at`  
import java.io.*; ~`{HWmah  
flLC\   
N2}].}  
public class FileAccessI implements Serializable{ 1GW=QbO 6  
%f@VOSs  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q5[%B K  
RandomAccessFile oSavedFile; /s=TLPm  
long nPos; oS$&jd  
_SC>EP8:Z  
CPGXwM=   
public FileAccessI() throws IOException 1H @GwQ|<=  
{ =?57*=]0M  
this("",0); / GJ"##<  
} ?/{ qRz'C<  
%.b)%=  
$<]y.nr|CX  
public FileAccessI(String sName,long nPos) throws IOException QHsS|\u  
{ +iwNM+K/gQ  
oSavedFile = new RandomAccessFile(sName,"rw"); 7BF't!-2F  
this.nPos = nPos; ;'pEzz?k"  
oSavedFile.seek(nPos); 1(!!EcU_  
} N`grr{*_  
|n=kYs  
L"tj DAV  
public synchronized int write(byte[] b,int nStart,int nLen) (>>pla^  
{ qEf )TW(  
int n = -1; cCU'~  
try{ *Yvfp{B  
oSavedFile.write(b,nStart,nLen); .Kq>/6  
n = nLen; ZH`6>:  
} o&?Tz*"l  
catch(IOException e) ~@bCSOIy  
{ ^C):yxN P  
e.printStackTrace (); }k<b)I*A  
} ygUvO3Z  
XT= #+  
_:M6~XHo  
return n; =YZp,{T  
} eJ%~6c`@!  
%o#D"  
"a`0s_F,^  
} bg_Zf7{  
0} liK  
!U,qr0h  
/* xwT"Q=|kW  
**SiteInfoBean.java ',6QL4qV/  
*/ aiw~4ix  
package NetFox; o|l)oc6{  
cdP+X'Y4D  
~@BV  
public class SiteInfoBean { xHykU;p@  
XT~JP  
Lvv`_  
private String sSiteURL; //Site's URL +5?hkQCX1^  
private String sFilePath; //Saved File's Path U`:#+8h-}  
private String sFileName; //Saved File's Name fPK|Nw]b  
private int nSplitter; //Count of Splited Downloading File B Ibcm,YQ  
DWk'6;e4j  
k%NY,(:(  
public SiteInfoBean() wm*`  
{//nSplitter的缺省值为5 5 ;dg#hO  
//default value of nSplitter is 5 pVt-7 AgW  
this("","","",5); yn!LJT[~2  
} CL9p/PJ%e  
A>7'W\R  
Gu*;z% b2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `x6 i5mp  
{ ,!%[CpM3  
sSiteURL= sURL; Jev@IORN\  
sFilePath = sPath; >4~{ CXZ  
sFileName = sName; ;?zb (2  
this.nSplitter = nSpiltter; {U^mL6=&v  
7ou2SL}k  
pgU54 Ef  
} <T  
jh\q2E~,`  
nF A7@hsm  
public String getSSiteURL() Zn #ri 8S  
{ OX|/yw8  
return sSiteURL; *tz"T-6O  
} MfeW|  
x*BfRj  
lOd[8|/  
public void setSSiteURL(String value) ':o.vQdJ  
{ #MGZje,I  
sSiteURL = value; us`hR!_  
} v{?9PRf\s  
quGb;)3  
]#S1 AvT  
public String getSFilePath() I \ vu?$w  
{ DNki xE*  
return sFilePath; T`a [~:  
} Y&'2/zI6~  
7OC ,KgJ3  
eSa ]6  
public void setSFilePath(String value) g[H7.  
{ mqq~&nI  
sFilePath = value; Xg,E;LSF8  
} w:M faN*  
N1#*~/sXh  
zq{L:.#ha  
public String getSFileName() 20%xD e  
{ Z33w A?9  
return sFileName; 4^AE;= Q  
} + ` Em&  
%0:  (''  
T=b5th}  
public void setSFileName(String value) r<&d1fM;X  
{ 5'l+'ox@J  
sFileName = value; ?1OS%RBF  
} <FGNV+?%e  
P}?,*'b  
uo 7AU3\  
public int getNSplitter() ~73YOGiGJH  
{ BszkQ>#6  
return nSplitter; bE]2:~  
} RMLs(?e  
*(o~pxFTR  
pw- C=MY]  
public void setNSplitter(int nCount) !Otyu6&  
{ s{IycTbz  
nSplitter = nCount; O$#`he/jm  
} 6"jq/Pu  
} q'K=Ly+  
_4.`$n/Z  
(MNbABZQ  
/* 61!R -  
**Utility.java O]^E%;(]}i  
*/ A5?[j QT0  
package NetFox; =GnDiI  
,pf<"^li  
BS+N   
public class Utility { l4r09"S|V  
&*MwKr<y  
_Y}(v( (;  
public Utility() kS=OX5  
{ Xv=n+uo  
+XFF@h&=t  
e:!&y\'"9  
} W~dS8B=<  
}v@w(*)h:  
//线程睡眠 aSKI %<?xN  
public static void sleep(int nSecond) MlS<txFPS  
{ oryoGy=(yk  
try{ )ZNH/9e/  
Thread.sleep(nSecond); {T m-X`  
} B{c,/{=O  
catch(Exception e) ETjlq]@j  
{ z#bO FVg#  
e.printStackTrace (); (AXS QI~y  
} KcNEB_i  
} KQQR"[z&V  
Wd&!##3$Q  
//日志 HPr5mWs:  
public static void log(String sMsg) 1 ,[T;pdDd  
{ GaM#a[p  
System.err.println(sMsg); (j}"1  
} Tv~<W4  
}MXZ  
g3Kc? wTC  
public static void log(int sMsg) Xm\tyLY  
{ jIAl7aoY  
System.err.println(sMsg); cKFzn+  
} duT2:~H2  
} UiaY0 .D  
zOWbdd_zl  
p4HX83y{  
/* [S-NGip  
**TestMethod.java jo{GPp}  
*/ [ o3}K  
package NetFox; I)Lg=n$  
VA4_>6  
(Dq3e9fX  
public class TestMethod { Dr,{V6^  
[ ecYpE<  
OHM.xw*?.  
public TestMethod() b\dBt#mB!  
{ ///xx/weblogic60b2_win.exe @6}c\z@AxM  
try{ .5KRi6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); YNHn# 98\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);  V:F)m!   
SiteFileFetch fileFetch = new SiteFileFetch(bean); 8WfF: R;  
fileFetch.start(); AEOo]b*&d  
} u{tjB/K&  
catch(Exception e){e.printStackTrace ();} JU/K\S2%,  
Gvl-q1PVC  
YeYFPi#  
} Wi hQj  
pkjL2U:  
uTBls8  
public static void main(String[] args) L7%Dc2{^(  
{ b3<<4Vf  
new TestMethod(); lmQ!q>N  
} DJ[U^dWRn  
} KX[_eO L  
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