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http断点续传简单实现(java)

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/* :"? boA#L  
**SiteFileFetch.java %J4]T35^2  
*/ \ &1)k/  
package NetFox; [z#C&gDt  
import java.io.*; vr5 6 f1  
import java.net.*; JG&`l{c9  
*u.6,jw  
Wh[+cH"M  
public class SiteFileFetch extends Thread { H6?ZE  
7cin?Z1  
yZ3/Ia>,  
SiteInfoBean siteInfoBean = null; //文件信息Bean jeF1{%  
long[] nStartPos; //开始位置 ?Z%Ja_}8ma  
long[] nEndPos; //结束位置 mMmzi4HL  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 iJ_`ZM.w  
long nFileLength; //文件长度 cAJKFu X"  
boolean bFirst = true; //是否第一次取文件 L;30& a  
boolean bStop = false; //停止标志 |qbCmsY5/  
File tmpFile; //文件下载的临时信息 7onMKMktM%  
DataOutputStream output; //输出到文件的输出流 Xm`s=5%  
6ae  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ]$(::'pmK  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,t5X'sY L  
{ *9)7.} uY  
siteInfoBean = bean; > kOca  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k7P~*ll$  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); aVvi_cau  
if(tmpFile.exists ()) p'1n'|$e  
{ E 5}T_~-{  
bFirst = false; )3v0ex@Jl  
read_nPos(); *0M#{HQ  
} 8[5%l7's  
else *9e T#dH  
{ AfW63;kH  
nStartPos = new long[bean.getNSplitter()]; 8=ubMqr[  
nEndPos = new long[bean.getNSplitter()]; Nw $io8:d  
} vc o/h  
I!lzOg4~  
~L Gkc t  
ElAJR4'{*i  
} adtK$@Yeg  
B' 6^E#9  
eU_|.2  
public void run() R-]QU`c  
{ _H@s^g  
//获得文件长度 dj4 g  
//分割文件 quk~z};R>\  
//实例FileSplitterFetch ^qqP):0y1V  
//启动FileSplitterFetch线程 RGYky3mQK  
//等待子线程返回 HRi~TZ?\  
try{ $+Ke$fq.>  
if(bFirst) 0$l=ME(  
{ `*PVFm>  
nFileLength = getFileSize(); 6u/3"A]'  
if(nFileLength == -1) x^_Wfkch]  
{ kH*l83  
System.err.println("File Length is not known!"); V[,/Hw~d%  
} \@nmM&7C!4  
else if(nFileLength == -2) yAtM|:qq  
{ "lLt=s2>L  
System.err.println("File is not access!"); zNRoFz.  
} lqA U5K{wQ  
else USu/Y29  
{ 6,M>'s,N  
for(int i=0;i<nStartPos.length;i++) ==(9P`\  
{ 7|PpAvMF  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #G{}Rd|!  
} gVCkj!{  
for(int i=0;i<nEndPos.length-1;i++) ||hy+f[A  
{ udB:ys  
nEndPos = nStartPos[i+1]; nk9hQRP? 8  
} *{tn/ro6a  
nEndPos[nEndPos.length-1] = nFileLength; a{Y:hrd:Z  
} o*97Nbjn  
} h *)spwF-  
? Ldw\  
mU:C{<Z  
//启动子线程 tp$NT.z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >#dNXH]9  
for(int i=0;i<nStartPos.length;i++) H7G*Vg  
{ "[@-p  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7;Km J}$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ',8]vWsl  
nStartPos,nEndPos,i); isHa4 D0  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $f>Mz|j  
fileSplitterFetch.start(); W-=~Afy  
} : QSlctW  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CZE5RzG  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); t)g1ICt  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Zb-TCS+3l  
nEndPos = " + nFileLength); &9PzBc  
// fileSplitterFetch[nPos.length-1].start(); xuO5|{h  
N-jFA8n  
TJ7on.;  
//等待子线程结束 lE08UEk1i  
//int count = 0; JI )+  
//是否结束while循环 1 Y@6oT  
boolean breakWhile = false; gj\r>~S  
;3Fgy8 T  
2i', e  
while(!bStop) #^<7VS!x  
{ N::_JH? ^=  
write_nPos(); `y0ZFh1>X  
Utility.sleep(500); 5ejdf  
breakWhile = true; *gHOH!K,S  
&PD4+%!  
IvetQ+  
for(int i=0;i<nStartPos.length;i++) gd.P%KC!g  
{ `j[)iok  
if(!fileSplitterFetch.bDownOver) v"O{5LM"  
{ _]1dm)%  
breakWhile = false; `kyr\+hp  
break; ^SxB b,\  
} eznw05U  
} 8U\;N  
if(breakWhile) 9%oLv25{)  
break; xBG&ZM4"^f  
/#9O{)  
HoymGU`w  
//count++; M]jzbJ3Q  
//if(count>4) $ePAsJ  
// siteStop(); )H S|pS:  
} wGd8q xa  
({Fus@/  
"vH@b_>9|  
System.err.println("文件下载结束!"); Y {Klwn   
} + }(  
catch(Exception e){e.printStackTrace ();} z|}Anc[\  
} eL^,-3JA(]  
EU ThH.  
=w".B[r  
//获得文件长度 ~Ht[kO  
public long getFileSize() 8l>/ZZ.NXi  
{ Cv{rd##Y8  
int nFileLength = -1; g Gg8O? Z  
try{ %&Z!-k(  
URL url = new URL(siteInfoBean.getSSiteURL()); !rb)Y;WQt  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J\_tigd   
httpConnection.setRequestProperty("User-Agent","NetFox"); (o{QSk\  
VyCBJK  
.zlUN0oe  
int responseCode=httpConnection.getResponseCode(); ; z:}OD  
if(responseCode>=400) :Ff1Js(Z  
{ h\C  
processErrorCode(responseCode); 9g"a`a?c  
return -2; //-2 represent access is error \PU|<Ru.  
} V5K`TC^  
?OYu BZF  
PAH; +  
String sHeader; Niou=PI@  
g[-'0d\1  
fbNVmjb$)  
for(int i=1;;i++) 93)&  
{ Da_g3z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0%k`* 8  
//Utility.log(in.readLine()); RFDwL~-p  
sHeader=httpConnection.getHeaderFieldKey(i); ;. !AX|v  
if(sHeader!=null) ?&)<h_R4p  
{ ;*wZgl  
if(sHeader.equals("Content-Length")) >8t3a-/  
{ DB:Ia5|*i  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .cQwj L  
break; kxWf1hIz0  
} %l,p />r  
} O9=vz%  
else #p*{p)]HiA  
break; p[hA?dXn  
} n8A*Y3~R  
} +_06{7@h  
catch(IOException e){e.printStackTrace ();} KSqWq:W+  
catch(Exception e){e.printStackTrace ();} pHni"i T  
fseHuL=~  
>LFhu6T  
Utility.log(nFileLength); bCdEItcD  
A"I:cw"KY  
epW;]> l  
return nFileLength; !(w\%$|  
} 7tUl$H;I/R  
q,^^c1f  
)+N%!(ki  
//保存下载信息(文件指针位置) \2: JX?Jw!  
private void write_nPos() 53=s'DZ  
{ I Vq9z  
try{ _yJd@  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @/`b:sv&*  
output.writeInt(nStartPos.length); <{9E.6G`n  
for(int i=0;i<nStartPos.length;i++) [US.n +G6  
{ fwf]1@#   
// output.writeLong(nPos); ;l &mA1+  
output.writeLong(fileSplitterFetch.nStartPos); HMS9_#[kE  
output.writeLong(fileSplitterFetch.nEndPos); 72&xEx  
} /(E)|*~6  
output.close(); -1:yqF.x  
} FoInJ(PDH  
catch(IOException e){e.printStackTrace ();} 1}QU\N(t  
catch(Exception e){e.printStackTrace ();} 1 ;4TA}'H  
} D/9&pRsO  
%S]5wR6;_  
f<!eJO:<'  
//读取保存的下载信息(文件指针位置) zRD{"uqi  
private void read_nPos()  z4&|~-m,  
{ (JL{X`gs#  
try{ y2TJDb1  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); PC7U&*x@  
int nCount = input.readInt(); * "~^k^_b}  
nStartPos = new long[nCount]; 31  QT  
nEndPos = new long[nCount]; i.)k V B  
for(int i=0;i<nStartPos.length;i++) Jf|J":S  
{ F[l{pc "C  
nStartPos = input.readLong(); ]{0 2!  
nEndPos = input.readLong(); F9]GEBLr  
} elJLTG  
input.close(); (Y)$+9  
} lmp0Ye|  
catch(IOException e){e.printStackTrace ();} m mu{K$9}I  
catch(Exception e){e.printStackTrace ();} ORA +>  
} @L=xY[&{  
Zvk O#j  
}Rt?p8p  
private void processErrorCode(int nErrorCode) <nvz*s  
{ !n}"D:L(  
System.err.println("Error Code : " + nErrorCode); Qg%B<3 <  
} R8W{[@  
hof:36 <  
<FRYt-+  
//停止文件下载 bfQ+}|;  
public void siteStop() WDP$w( M  
{ rMH\;\ I|U  
bStop = true; GW]Ygf1t  
for(int i=0;i<nStartPos.length;i++) K`M8[ %S  
fileSplitterFetch.splitterStop(); @@# ^G8+l  
va:5pvt2&  
KaauX m  
} f]qP xRw  
} {3i.U028]  
//负责部分文件的抓取 0AZ Vc  
**FileSplitterFetch.java ido'<;4>  
*/ ?N~rms e  
package NetFox; Vge9AH:op  
jRm v~]  
!eMz;GZ  
import java.io.*; ry*b"SO  
import java.net.*; GASDkVoij  
$GSn#} yz  
^Cst4=:W  
public class FileSplitterFetch extends Thread { !.?2zp~  
,@;",  
N41)?-7F  
String sURL; //File URL o 3#qp>R  
long nStartPos; //File Snippet Start Position :3gtc/pt>  
long nEndPos; //File Snippet End Position 2>Xgo%  
int nThreadID; //Thread's ID *_}ft-*w  
boolean bDownOver = false; //Downing is over Ovq-rI{  
boolean bStop = false; //Stop identical A% -*M 'J  
FileAccessI fileAccessI = null; //File Access interface z|Q)^  
}G]6Rip 3  
#e}Q|pF  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $>hPB[[  
{ `k+ci7;  
this.sURL = sURL; `1=n H/E  
this.nStartPos = nStart; H!y1&  
this.nEndPos = nEnd; _rdEur C6  
nThreadID = id; ': 87.8$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 yTm/P!1S  
} 2`9e20  
%?Yf!)owh  
)>QpR8 G-  
public void run() ^RAst1q7  
{ fZw/kjx@  
while(nStartPos < nEndPos && !bStop) p9 <XaJ}   
{ 1Mn=m w  
DI{VJ&n66  
9. 6"C<eYt  
try{ p[2`H$A  
URL url = new URL(sURL); F0qpJM,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y'(( tBWa!  
httpConnection.setRequestProperty("User-Agent","NetFox"); s/"&k  
String sProperty = "bytes="+nStartPos+"-"; n0bm 'qw  
httpConnection.setRequestProperty("RANGE",sProperty); Hz ) Xn\x  
Utility.log(sProperty); RP9#P&Qk  
(u-K^xC  
w[YiH $  
InputStream input = httpConnection.getInputStream(); iH<:wLY&J  
//logResponseHead(httpConnection); J&CA#Bg:w  
}`ox;Q  
oJ734v[X  
byte[] b = new byte[1024]; Xia4I* *  
int nRead; R.@I}>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) wW EnAW~  
{ <tXk\ cOg  
nStartPos += fileAccessI.write(b,0,nRead); t 1}R#NB  
//if(nThreadID == 1) !w2J*E\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Q"7vzri  
} Y&!-VW  
MKPxF@N(  
|L[/]@|  
Utility.log("Thread " + nThreadID + " is over!"); {k*rD!tT  
bDownOver = true; ^ >JAl<k  
//nPos = fileAccessI.write (b,0,nRead); i=T!4'Zu  
} Tsg;i;  
catch(Exception e){e.printStackTrace ();} .;}vp*  
}  UCV1{  
} !0!m |^c5  
$ha,DlN  
3V=wW{;x  
//打印回应的头信息 >!sxX = <  
public void logResponseHead(HttpURLConnection con) C$WUg<kcK'  
{ r&+8\/{  
for(int i=1;;i++) +i^@QNOa  
{ cZC%W!pT  
String header=con.getHeaderFieldKey(i); 5QN~^  
if(header!=null) 3w!8PPl  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'tvX.aX2  
Utility.log(header+" : "+con.getHeaderField(header)); cQ}3? v  
else xKl\:}Ytp  
break; AK$&'t+$}7  
} *ThP->&:(  
} 4FQB%3>*  
*Tc lc u  
e_=TkG1E6  
public void splitterStop() StLFq6BO  
{ O{^8dwg  
bStop = true; ~H`m"4zQ  
} i&mcM_g32  
Fi)(~ji:  
RK )1@Tz7!  
} <ks+JkW_  
Hq$&rNnq\  
{$qE>ic  
/* M/?eDW/  
**FileAccess.java &~=FX e0S  
*//文件访问(定位,写) _cvA1Q"  
package NetFox; ['m7Wry  
import java.io.*; $,u>,  
*!oV?N[eA'  
%9vl  
public class FileAccessI implements Serializable{ Fz11/sKz  
?}g^/g !  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q7z`oK5  
RandomAccessFile oSavedFile; 1 A%0y)]  
long nPos; lT^/ 8Z<g  
-.xiq0  
Mc,3j~i  
public FileAccessI() throws IOException *T6*Nxs0k  
{ +~(SeTY  
this("",0); KE[!{O^(a  
} C&|K7Zp0v  
 jYUN:  
L:j3  
public FileAccessI(String sName,long nPos) throws IOException *Xcqnu('  
{ uM)#T*(  
oSavedFile = new RandomAccessFile(sName,"rw"); JAx0(MZO  
this.nPos = nPos; x52#md-Z  
oSavedFile.seek(nPos); fHK.q({Qc  
} &R5zt]4d&  
A=W:}szt]  
_mWVZ1P  
public synchronized int write(byte[] b,int nStart,int nLen) ]*?lgwE  
{ &&% oazR=  
int n = -1; 7F2 WmMS  
try{ | |"W=E  
oSavedFile.write(b,nStart,nLen); t"JE+G  
n = nLen; "7q!u,u  
} F[(ocxQZ3  
catch(IOException e) E)%D LZ  
{ .8wf {y  
e.printStackTrace (); ZJe^MnE (G  
} `=V p 0tPI  
EDT9O  
O!!N@Q2g  
return n; j*\oK@  
} 40%fOu,u`  
qxB|*P `  
gLm,;'h%u  
} x8w l  
?;VsA>PV  
+=:_a$98  
/* `>0%Ha   
**SiteInfoBean.java 577#A,O  
*/ 3n,jrX75u  
package NetFox; cO$xT;kK  
!>\&*h-Cm#  
5^D094J|^  
public class SiteInfoBean { )SZzA'  
QLH!>9Ch  
i 50E#+E8  
private String sSiteURL; //Site's URL en>n\;U  
private String sFilePath; //Saved File's Path > ^=n|%  
private String sFileName; //Saved File's Name q68CU~i*  
private int nSplitter; //Count of Splited Downloading File JC0#pU;  
{]bmecz  
Y'{}L@"t  
public SiteInfoBean() tD*k   
{//nSplitter的缺省值为5 )T6:@n^]h  
//default value of nSplitter is 5 qt(4?_J  
this("","","",5); z3Yi$*q <  
} 5dGfO:Dy_  
9wlp AK  
-T}r$A  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 15@2h  
{ r+8)<Xt+p  
sSiteURL= sURL; yAAV,?:o[  
sFilePath = sPath; #+QJ5VI :  
sFileName = sName; uI$n7\G!  
this.nSplitter = nSpiltter; NN#k^[i1  
4> uNH5  
n }b{u@$  
} ^k*%`iQ  
[>N#61CV 5  
0SU v5c  
public String getSSiteURL() p>,D F9W`  
{ |sI@m@  
return sSiteURL; 0BNH~,0u  
} wmww7  
j!@T@ 8J  
~/X8Hy!-  
public void setSSiteURL(String value) vf zC2  
{ Nyt*mbd5 {  
sSiteURL = value; k-H6c  
} [;yKbw!C  
{+zG.1o^  
V:#rY5X  
public String getSFilePath() gg.]\#3g  
{ & #JYh=#  
return sFilePath; 118lb]  
} fP:]s@$  
mKjTJzS  
O&MH5^I  
public void setSFilePath(String value) ;O1jf4y  
{ LofpBO6^  
sFilePath = value; b}fC' h  
} BYu(a  
>|, <9z`D  
P4HoKoj2`  
public String getSFileName() 7m  ou  
{ -.r"|\1X  
return sFileName; TFG? EO  
} :8(jhs  
8!0fT}  
1$1>cuu  
public void setSFileName(String value) 3b\s;!  
{ ]?)uYot  
sFileName = value; c&1_lI,tH  
} (V&8 WN  
pj<aMh  
2Y%7.YX"  
public int getNSplitter() lX%-oRQ/os  
{ sVr|kvn2  
return nSplitter; KAXjvZN1  
} t #Kucde  
KB^8Z@(+  
V,=5}qozQ  
public void setNSplitter(int nCount) XlD=<$Nk7  
{ VQ,5&-9Y3  
nSplitter = nCount; 1TX3/]:  
} tH&eKM4G  
} tvf5b8(Y-  
K\KQ(N8F  
y{&%]Fq <5  
/* k-a1^K3  
**Utility.java A9N8Hav  
*/ bl&9O  
package NetFox; hxj\  
&"W gO!pzD  
>]anTF`d  
public class Utility { nBd]rak'  
w>\oz  
j94~c YV  
public Utility() O'B3sy  
{ +,,dsL  
.wp[uLE  
cLp_\\  
} 5 =8v\q?)c  
M"W#_wY;  
//线程睡眠 BKO^ux%  
public static void sleep(int nSecond) cWyf04-?  
{ WMnSkO  
try{ 7D,nxx(`  
Thread.sleep(nSecond); @I|kY5'c  
} kP}l"CN4  
catch(Exception e) VRgckh m  
{ n|?sNM<J3  
e.printStackTrace (); OM^`P  
} =$+0p3[r  
} wl%ysM| x  
ZbVn"he  
//日志 )X," NJG  
public static void log(String sMsg) "=K3sk  
{ V~#5^PF{  
System.err.println(sMsg); I$S*elveG  
} jl}!UG  
Xs|d#WbX  
*;McX  
public static void log(int sMsg) ;F*^c )  
{ *g %bdO  
System.err.println(sMsg); rXz q :  
} [kpQ:'P3  
} $L( ,lB  
mE1Vr  
=SuJ*  
/* /eU\B^k  
**TestMethod.java KPDJ$,:  
*/ V1Ojr~iM  
package NetFox; w8~R=k  
(=WbLNBS  
olr#3te  
public class TestMethod { N.+A-[7,W  
x^_c4,i)  
a!4p$pR  
public TestMethod() = 03G~7B>  
{ ///xx/weblogic60b2_win.exe _-H,S)kI`  
try{ Vt \g9-[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =jh^mD&'  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TD*AFR3Oz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^tSwAanP\  
fileFetch.start(); h?;03>6A&]  
} A@?-"=h}  
catch(Exception e){e.printStackTrace ();} ns~bz-n  
rQNm2h  
+~YoP>  
} 2Mq@5n  
)(yaX  
v!DK.PZbi  
public static void main(String[] args) )Ghw!m  
{ qhG2j;  
new TestMethod(); ^K::g)  
} ^\ln8!;  
} ^8bc<c:P  
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