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http断点续传简单实现(java)

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/* ]t3"0  
**SiteFileFetch.java Q2NnpsA^6  
*/ ,Tl5@RN  
package NetFox; .[fz x`  
import java.io.*; %}!}2s.A  
import java.net.*; n4 @a`lN5g  
DV\ei")  
g8"7wf`0k  
public class SiteFileFetch extends Thread { h12wk2@P/]  
U08?*{  
i 8Xz  
SiteInfoBean siteInfoBean = null; //文件信息Bean ~a%hRJg  
long[] nStartPos; //开始位置 RKkI/Z0  
long[] nEndPos; //结束位置 NR&9:?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *"\Q ~#W  
long nFileLength; //文件长度 m[j3s=Gr  
boolean bFirst = true; //是否第一次取文件 Z5L1^  
boolean bStop = false; //停止标志 zYdtQjv  
File tmpFile; //文件下载的临时信息 bl?%:qb.V  
DataOutputStream output; //输出到文件的输出流 )^Pvm  
}YP7x|  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) :(`>bY  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?ljod6  
{ Ne7{{1  
siteInfoBean = bean; ;x^,t@ xge  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); S\5k' ifh  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); b H_pNx81  
if(tmpFile.exists ()) c$kb0VR  
{ ON0+:`3\  
bFirst = false; *v ^"4  
read_nPos(); +~ Ay h[V  
} O)uM&B=  
else QCfpDE}  
{ !<zzP LC  
nStartPos = new long[bean.getNSplitter()]; '5/}MMT  
nEndPos = new long[bean.getNSplitter()]; d J:x1j  
} Q'% o;z*  
_-J@$d%  
sC_UalOC_  
/2Lo{v=0[  
} JlQT5k  
=awO63j>  
@:9fS  
public void run() t} i97;  
{ 7&1~O#  
//获得文件长度 m2CWQ[u  
//分割文件 .Pes{uHg  
//实例FileSplitterFetch oz6+rM6MY  
//启动FileSplitterFetch线程 i:M*L< +  
//等待子线程返回 #pQ"+X  
try{ -5v.1y=!L  
if(bFirst) pptM &Y  
{ 4)+IO;  
nFileLength = getFileSize(); .*~u  
if(nFileLength == -1) /cC6qhkp%  
{ YOV4)P"  
System.err.println("File Length is not known!"); E97+GJ3  
} h<1dTl*  
else if(nFileLength == -2) iEVA[xy=D  
{ r`R~{;oT  
System.err.println("File is not access!"); 2HGD{;6>v{  
} p;=kH{uu  
else ),Ho(%T\  
{ )_ ^WpyzF1  
for(int i=0;i<nStartPos.length;i++) ^I<T+X+<  
{ MJKl]&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); cYM~IA  
} U+PCvl=x  
for(int i=0;i<nEndPos.length-1;i++) Cz@FZb8  
{ TDFO9%2c  
nEndPos = nStartPos[i+1]; ^b!7R <>~  
} mH*@d"  
nEndPos[nEndPos.length-1] = nFileLength; $7n#\h  
} iSr`fQw#  
} Ivt} o_b*  
L> Oy7w)Y  
gJ5wAK+?  
//启动子线程 bV$8 >[`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3$N %iE6  
for(int i=0;i<nStartPos.length;i++) ^jha:d  
{ 9c^skNbS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B >u,)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), D<bU~Gd,P  
nStartPos,nEndPos,i); [Ba2b: l6v  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W `u$7k]$  
fileSplitterFetch.start();  =Etwa  
} _TOi [G T  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), y,v0-o~q  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <L/M`(:=k  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", XK%W^a*x  
nEndPos = " + nFileLength); Q5y q"/=[a  
// fileSplitterFetch[nPos.length-1].start(); e-iYJ?  
,V33v<|wc  
J7ktfyQ0W  
//等待子线程结束 `xX4!^0Hm  
//int count = 0; PPCTc|G  
//是否结束while循环 $35,\ZO>  
boolean breakWhile = false; VXkAFgO  
KIKq9*  
A3"1D  
while(!bStop) umm\r&]A  
{ *"ykTqa  
write_nPos(); kQwm"Z  
Utility.sleep(500); +2EHmuJ;  
breakWhile = true; ]D{c4)\7C|  
Bn1L?>G  
2~M;L&9-  
for(int i=0;i<nStartPos.length;i++) dqD;y#/  
{ 8K.s@<  
if(!fileSplitterFetch.bDownOver) oE!hF}O  
{ i'!jx.  
breakWhile = false; cBab2/  
break; 2 {mY:\  
} ?-8y4 Ex  
} "J P{Q  
if(breakWhile) >HcYVp~G  
break; TwM1M["3  
m|[\F#+C  
nY{i>Y  
//count++; NokXE  
//if(count>4) U~{Sa+  
// siteStop(); gb=80s0  
} YER:ICQ  
ZI58XS+  
DYo<5^0  
System.err.println("文件下载结束!"); wi\z>'R  
} Y_[g_  
catch(Exception e){e.printStackTrace ();} 5ys #L&q'Z  
} oUQGLl!V  
b&=]S(  
7.Ml9{M/i  
//获得文件长度 <`c25ih.4  
public long getFileSize() v9E+(4I9_  
{ &<gUFcw7Ui  
int nFileLength = -1; 7szls71/=  
try{ j`2B}@2  
URL url = new URL(siteInfoBean.getSSiteURL()); MV0<^/p|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4ef*9|^x#  
httpConnection.setRequestProperty("User-Agent","NetFox"); a9#W9eP  
20rN,@2<  
n> MD\ZS  
int responseCode=httpConnection.getResponseCode(); N@cMM1  
if(responseCode>=400) 5mI?pfm  
{ 6Cl+KcJH  
processErrorCode(responseCode); v]WH8GI  
return -2; //-2 represent access is error 9U2Px$E  
} Z$!C=  
@+?+6sS  
AA))KBXq  
String sHeader; >vQ6V'F  
_&W0e}4  
kU #:I9PO  
for(int i=1;;i++) f\h%; X  
{ ,dHP`j ?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); [#7y[<.P  
//Utility.log(in.readLine()); lir &e 9I+  
sHeader=httpConnection.getHeaderFieldKey(i); D3%l4.h  
if(sHeader!=null) T@(6hEmP,  
{ LKqRvPnh  
if(sHeader.equals("Content-Length")) cJP'ShnCh  
{ `aO.=:O_  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); >65 TkAp  
break; "0|BoG  
} m9#}X_&x  
} X,>(Y8  
else 3%XG@OgP  
break; ^pJ0nY# c  
} {B@*DQv  
} .=Pm>o/,  
catch(IOException e){e.printStackTrace ();} UUl*f!& o  
catch(Exception e){e.printStackTrace ();} n<{aPLQ  
{hxW,mmA  
M} O[`Fx{W  
Utility.log(nFileLength); s,84*6u  
4$%`Qh>yA  
65lOX$*{-  
return nFileLength; Jf_]Z  
} c`-YIz)W  
pAEN XC\,  
mH'\:oN  
//保存下载信息(文件指针位置) =f o4x|{O  
private void write_nPos() f 4R1$(<  
{ /ca(a\@R  
try{ h=hoV5d@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); DeA@0HOxh  
output.writeInt(nStartPos.length); }g}6qCv7  
for(int i=0;i<nStartPos.length;i++) 3nwz<P  
{ !loO%3_)  
// output.writeLong(nPos); ]a)IMIh;  
output.writeLong(fileSplitterFetch.nStartPos); = Q@6c   
output.writeLong(fileSplitterFetch.nEndPos); yHl@_rN sC  
} M6\7FP6G  
output.close(); @|^jq  
} Z%Vr+)!4  
catch(IOException e){e.printStackTrace ();} ?hKm&B;d  
catch(Exception e){e.printStackTrace ();} 6%>/og\%  
} NP "ylMr7P  
9-b 8`|s  
R^w}o,/  
//读取保存的下载信息(文件指针位置) M]1;  
private void read_nPos() GN0duV  
{ N.jA 8X  
try{ Hv3W{|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ?<E0zM+  
int nCount = input.readInt(); 2pz4rc  
nStartPos = new long[nCount]; $1~c_<DN  
nEndPos = new long[nCount]; uw_H:-J  
for(int i=0;i<nStartPos.length;i++) ~,T+JX  
{ Oohq9f#!  
nStartPos = input.readLong(); )qmFK .;%  
nEndPos = input.readLong(); goB;EWz  
} gd K*"U  
input.close(); F, zG;_  
} _1P`]+K\D$  
catch(IOException e){e.printStackTrace ();} PzLJ/QER  
catch(Exception e){e.printStackTrace ();} YN/u9[=`  
} C *a,<`  
`T=1<Twc  
$}db /hY*  
private void processErrorCode(int nErrorCode) n_J5zQJ  
{ Jns/v6  
System.err.println("Error Code : " + nErrorCode); ]Ym=+lgi  
} %0lf  
VxkEez'|  
|e:rYLxm:  
//停止文件下载 ly[lrD0Kn.  
public void siteStop() a/ b92*&k  
{ kB V/rw  
bStop = true; >{b3>s~T  
for(int i=0;i<nStartPos.length;i++) };^}2Xo+  
fileSplitterFetch.splitterStop(); ]'tJ S]  
4b=Gg  
\KCWYi]  
} lr0M<5d=p  
} zXjw nep  
//负责部分文件的抓取 AxEc^Cof  
**FileSplitterFetch.java rEmwKZF'  
*/ Si]X rub  
package NetFox; gn^!"MN+g  
?T <rt  
~~@y_e[N#l  
import java.io.*; 'aZAS Pn[  
import java.net.*; S_$nCyaH2  
eKyqU9  
SetX#e?q~  
public class FileSplitterFetch extends Thread { p.5e: i^LJ  
nn'Af,ko/  
~{$L9;x  
String sURL; //File URL H~eGgm;p  
long nStartPos; //File Snippet Start Position |*ReqM|_C  
long nEndPos; //File Snippet End Position 3[.3dy7,Z  
int nThreadID; //Thread's ID >C*4_J7  
boolean bDownOver = false; //Downing is over nSHNis  
boolean bStop = false; //Stop identical lA]N04 d  
FileAccessI fileAccessI = null; //File Access interface _CL{IY  
m d_g}N(C  
}1Z6e[K?  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException tJAnuhX  
{ L?Cjo4xS  
this.sURL = sURL; WI{; #A  
this.nStartPos = nStart; :xtT)w  
this.nEndPos = nEnd; @<a|  
nThreadID = id; M|H 2kvl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  pr/'J!{^  
} Y0}4WWV  
i(Vm!Y82  
F<gMUDB  
public void run() c ;^A)_/  
{ {!r#f(?uT  
while(nStartPos < nEndPos && !bStop) R+uw/LG  
{ ;?`@"YG)  
iu|v9+  
C5MqwNX  
try{ 7 OWsHlU  
URL url = new URL(sURL); # M>wH`Q#  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); +|0 t  
httpConnection.setRequestProperty("User-Agent","NetFox"); >: $"a  
String sProperty = "bytes="+nStartPos+"-"; }#bZ8tm&  
httpConnection.setRequestProperty("RANGE",sProperty); GMw)*  
Utility.log(sProperty); *Dc@CmBr  
YD9!=a$  
fbV@=(y?  
InputStream input = httpConnection.getInputStream(); .`+yo0O:  
//logResponseHead(httpConnection); O J>iq@ >  
5NFRPGYX  
a%*_2#  
byte[] b = new byte[1024]; -K^41W71  
int nRead; ^vM_kAr A  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 1]Lh'.1^  
{ P7UJ-2%Y+  
nStartPos += fileAccessI.write(b,0,nRead); R>HY:-2  
//if(nThreadID == 1) Why"G1`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); f"P$f8$  
} &`@lB (m  
U=DEV7E  
Zw24f1iY  
Utility.log("Thread " + nThreadID + " is over!"); 8i[LR#D)  
bDownOver = true; Yv=g^tw  
//nPos = fileAccessI.write (b,0,nRead); T%~SM5  
} A2 BRbwr>  
catch(Exception e){e.printStackTrace ();} -N4z-ozhC  
} GXYj+ qJ  
} _r5wF(Y?7  
7>mhK7l  
Wc\+x1:8  
//打印回应的头信息 ZB0+GG\  
public void logResponseHead(HttpURLConnection con) Eu4 &-i  
{ zi.mq&,]R  
for(int i=1;;i++) z7k$0&  
{ P5P< "  
String header=con.getHeaderFieldKey(i); t R ;{.  
if(header!=null) q5?{ 1  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); gwq`_/d}  
Utility.log(header+" : "+con.getHeaderField(header)); D )gD<  
else #g{Mne  
break; HU9p !I.  
} `x2,;h!:)N  
} & g$rrpTzv  
73)Ll"(  
ZPvf-Pq Jl  
public void splitterStop() CW;m  
{ 1daL y  
bStop = true; :q;R6-|.  
} }DHUTP2;yz  
O4!9{  
xEC 2@J  
} $P;UoqG<&  
Man^<T%F  
Xb0!( (A  
/* O]bKNA.5  
**FileAccess.java yKlU6t&` G  
*//文件访问(定位,写) i7s\CY  
package NetFox; .R\p[rv&  
import java.io.*; 8JP6M!F#  
FJF3B)Va|  
gi1j/j7  
public class FileAccessI implements Serializable{  Oq}ip  
Ck@M<(x  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^9=4iXd  
RandomAccessFile oSavedFile; om>VQ3  
long nPos; Ko+al{2  
Q0WY$w1 <  
x G^f  
public FileAccessI() throws IOException zQ<88E&&Xs  
{ 2NYi-@mr  
this("",0); ftaBilkjp  
} kfRJ\"`   
d EI a=e|  
K-6p'|  
public FileAccessI(String sName,long nPos) throws IOException +dM.-wW  
{ 71*>L}H  
oSavedFile = new RandomAccessFile(sName,"rw"); PF6 7z]<o  
this.nPos = nPos; >Zo-wYG  
oSavedFile.seek(nPos); B>@D,)/bT5  
} 9 ?(x>P  
T\fudmj&  
Az9J\V~"  
public synchronized int write(byte[] b,int nStart,int nLen) 8F)=n \  
{ !?6.!2  
int n = -1; A6Q c;v+  
try{ ,# eO&  
oSavedFile.write(b,nStart,nLen); Lrlk*   
n = nLen; U&X.  
} ) G|"jFP  
catch(IOException e) {zu/tCq?  
{ ,O2q+'&  
e.printStackTrace (); @ct#s:t  
} 2]3G1idB  
;M-,HK4=  
j C9<hLt  
return n; %]!?{U\*k  
} sSV^5  
3<3t;&e  
5c)wZ  
} aX]y`  
Lg b  
1 0V+OIC  
/* FbuKZp+  
**SiteInfoBean.java c[Yq5Bu{y  
*/ ]a=l^Pc(xN  
package NetFox; PB@-U.Z  
h~:H?pj3g  
[&Lxz~W][  
public class SiteInfoBean { L PMb0F}"5  
GV=V^Fl .  
i6FP[6H1  
private String sSiteURL; //Site's URL 9c%(]Rn:  
private String sFilePath; //Saved File's Path Gy$o7|PA"{  
private String sFileName; //Saved File's Name g{]ej  
private int nSplitter; //Count of Splited Downloading File F; 0Dp  
#|q;t   
,rXW`7!2  
public SiteInfoBean() bu;vpNa  
{//nSplitter的缺省值为5 ]Px:d+wX:  
//default value of nSplitter is 5 XGL"gD   
this("","","",5); aK-N}T  
} N*? WUn9]  
CO7CNN  
)|Jr|8  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,I=O"z>9  
{ 6B /Jp  
sSiteURL= sURL; Z"+(LO!  
sFilePath = sPath; } cRi A  
sFileName = sName; IK85D>00T  
this.nSplitter = nSpiltter; rtoSCj:  
r!>es;R8  
lf}?!*V`+  
} JW2W>6Dgv[  
.ZM]%[4  
U24V55ZnI  
public String getSSiteURL() V.+DP  
{ rC=f#YjR  
return sSiteURL; h@ EJTAi  
} <x^IwS  
v#w4{.8)  
 PVS\,  
public void setSSiteURL(String value) |I4D(#w.  
{ v!iWzN  
sSiteURL = value; ^j1Gmv)  
} )_WH#-}  
^BQ>vI'.4  
>Y44{D\`  
public String getSFilePath() bXk:~LE  
{ x`wZtv\  
return sFilePath; Tm0?[[3hC  
} m21QN9(i%  
u)wu=z8  
k:@a[qnY  
public void setSFilePath(String value) 1i ?gvzrq  
{  j@s=ER  
sFilePath = value; &IxxDvP3k  
} ^a: Saq-}  
ikeJDKSG  
@?(nwj~ s`  
public String getSFileName() + ?[ ACZF  
{ hrUm} @d  
return sFileName; \3,$YlG  
} 3XMBu*  
\;4L~_2$q  
-<u- +CbuT  
public void setSFileName(String value) Z1 E` I89<  
{ Q3'(f9 x  
sFileName = value; ] `b<"  
} [J(@$Qix  
WlF+unB!9  
)cf p(16  
public int getNSplitter() R V_MWv  
{ 7/$nA<qM  
return nSplitter; nI((ki}v  
} $yP'k&b!  
9J't[( u|u  
qen44;\L  
public void setNSplitter(int nCount)  WMt&8W5  
{ ]0at2  
nSplitter = nCount; &6=TtTp"9  
} Q%_!xQP`  
} E,"b*l.  
:..E:HdYO  
w-{#6/<kI5  
/* /@xr[=L  
**Utility.java hnM9-hqm  
*/ !xJLeQFJI]  
package NetFox; !;BZ#tF&  
!07FsPI#{  
xF\}.OfWG  
public class Utility {  Ep#<$6>  
p0%6@_FT~  
4DG 9`5.  
public Utility() ;@h'Mb  
{ 98"z0nI%  
sYW1T @  
4okHAv8;  
} n]kQtjJ  
fS8XuT  
//线程睡眠 _ d(Ks9  
public static void sleep(int nSecond) v ](G?L9b  
{ i75?*ld  
try{ `"^@[1  
Thread.sleep(nSecond); =PeW$q+  
} N7Z(lI|a;  
catch(Exception e) *IjdN,wox  
{ ^Y*`D_-G  
e.printStackTrace (); Cz$H k;3\6  
} jSOa   
} q_%w l5\F  
Y'+F0IZ+  
//日志 wnZ*k(  
public static void log(String sMsg) Xm0&U?dZB  
{ oK(W)[u  
System.err.println(sMsg); N'Z_6A*-  
} <*b]JY V@  
iPtm@f,bI  
 CU7iva  
public static void log(int sMsg) j|VlHDqR  
{ eX]9m Q]E  
System.err.println(sMsg); {U+9,6.`  
} MFCbx>#  
} pXh^M{.  
z?IY3]v*z<  
:*w:eKk  
/* `,8R~-GPD  
**TestMethod.java p0:&7,+a,  
*/ 4u{E D(  
package NetFox; eF gb6dSh  
z!t3xFN&/  
Kr+Bt y  
public class TestMethod { A{n*NxKCX!  
x"h)"Y[c5  
:a^,Ei-&  
public TestMethod() I _Mqh4];  
{ ///xx/weblogic60b2_win.exe 0 6G[^  
try{ 6{F S /+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w$<fSe7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); v=yI#5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); QBBJ1U  
fileFetch.start(); .-1{,o/&Q  
} !MG>z\:  
catch(Exception e){e.printStackTrace ();} L{o >D"  
>> 8KL`l  
ZCOuv6V+  
} *|.yX%"k  
7HR%rO?'  
aGzdur  
public static void main(String[] args) VHXR)}  
{ $4ZDT]n  
new TestMethod(); #\!hBL @b  
} "l2N_xX;  
} [7 Kj$PB3  
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