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http断点续传简单实现(java)

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/* P;X0L{u0H  
**SiteFileFetch.java ulEtZ#O{_  
*/ J!Rqm!)q  
package NetFox;   LR4W  
import java.io.*; n(n7"+B  
import java.net.*; #!m^EqF1_  
"79b>  
>r4BI}8SK<  
public class SiteFileFetch extends Thread { u2':~h?l  
c*(=Glzn  
V6Of(;r  
SiteInfoBean siteInfoBean = null; //文件信息Bean b ts*qx&)  
long[] nStartPos; //开始位置 PKGqu,J,  
long[] nEndPos; //结束位置 )1YGWr;ykS  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 plzwk>b_  
long nFileLength; //文件长度 Hg\H>Z  
boolean bFirst = true; //是否第一次取文件 )wEXCXr!  
boolean bStop = false; //停止标志 :4\_upRE  
File tmpFile; //文件下载的临时信息 h7xgLe@  
DataOutputStream output; //输出到文件的输出流 ,&@FToR  
h,/3 }  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ;ae6h [  
public SiteFileFetch(SiteInfoBean bean) throws IOException Kr4%D*  
{ daf-B-  
siteInfoBean = bean; ,z((?h,nm  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); e)L!4Y44K  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); q#8z%/~k  
if(tmpFile.exists ()) !:_krLB<  
{ J3r':I}\  
bFirst = false; JvJ)}d$,&  
read_nPos(); 5a&gdqg]  
} # M Y4Mr  
else kc@ \AZb  
{ <rU+{&FKNL  
nStartPos = new long[bean.getNSplitter()]; X&i" K'mV  
nEndPos = new long[bean.getNSplitter()]; 20Rm|CNH?  
} ZS&lXgo  
nXh<+7  
f\:I1y  
Z#GR)jb+  
} \x_$Pu  
{PL,3EBG  
y}W*P#BDO  
public void run()  Kc3/*eu;  
{ ;~}!P7z  
//获得文件长度 Ax4;[K\Q  
//分割文件 eW_EWVH  
//实例FileSplitterFetch nxuR^6 Ai  
//启动FileSplitterFetch线程 H_l>L9/\  
//等待子线程返回 B+'w'e$6  
try{ Lf Y[Z4  
if(bFirst) "?J f#  
{ D]V&1n  
nFileLength = getFileSize(); AUaupNN  
if(nFileLength == -1) $BOIa  
{ 25;`yB$  
System.err.println("File Length is not known!"); X(>aW*q  
} D6P/39}W  
else if(nFileLength == -2) Z~"8C Kz  
{ 7P52r  
System.err.println("File is not access!"); 'f.5hX(Y  
} H_%ae' W  
else <9Ytv|t@0  
{ L\t!)X-4  
for(int i=0;i<nStartPos.length;i++) 4DGKZh'm"  
{ y8|}bd<Sr  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); iz`ys.Fu  
} Lo9 \[4FP  
for(int i=0;i<nEndPos.length-1;i++) h*mKS -TC  
{ z9zo5Xc=  
nEndPos = nStartPos[i+1]; lF$$~G  
} tkdyR1-  
nEndPos[nEndPos.length-1] = nFileLength; uF T5Z  
} c+<gc:#jy  
} tQ2S*]"f  
W6yz/{Rf  
/ DS T|2  
//启动子线程 ZD8E+]+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; pzDz@lAwR  
for(int i=0;i<nStartPos.length;i++) V##TG0  
{ * \ tR  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N)YoWA>#bF  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :-b-)*TC;  
nStartPos,nEndPos,i); R9Y{kk0M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JaJyH%+$!  
fileSplitterFetch.start(); &([yI>%  
} \@j3/!=,n%  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &$pA,Gjin\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); i]zTY\gw8M  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Dr#V^"Dte  
nEndPos = " + nFileLength); ,j[1!*Z_[  
// fileSplitterFetch[nPos.length-1].start(); `$r?^|T  
,Q8h#0z r  
/^ [K  
//等待子线程结束 l37l| xp~  
//int count = 0; ,,V uvn  
//是否结束while循环 xT8!X5;  
boolean breakWhile = false; zvbz3a  
EJ Ta~  
S%w67sGl4n  
while(!bStop) OKNGV,{`  
{ |Lz7}g=6  
write_nPos(); .@f )#2  
Utility.sleep(500); "(E%JAwZ^W  
breakWhile = true; &. "ltB  
$K!6T  
au7@-_  
for(int i=0;i<nStartPos.length;i++) S2 YxA  
{ <V4"+5cJ8  
if(!fileSplitterFetch.bDownOver) ^|%7}=e  
{ +PHuQ  
breakWhile = false; _dn*H-5hO  
break; boIFN;Aq"  
} q%Lw#f  
} ch0x*[N@  
if(breakWhile) ~ZRtNL9   
break; N|s8PIcSp  
x@<!#d+  
l65Qk2<YC  
//count++; s Qa9M  
//if(count>4) )Z@hk]@?_[  
// siteStop(); fH;lh-   
} Oat #%  
%lN4"jtx  
jD_B&MQz  
System.err.println("文件下载结束!"); IS }U2d,W  
} O:[@?l  
catch(Exception e){e.printStackTrace ();} VN<baK%]  
} hKFB=U  
[{rne2sA  
q&EwD(k  
//获得文件长度 N+ei)-  
public long getFileSize() HlX2:\\  
{ ]"\XTL0  
int nFileLength = -1; VDPq3`$+v{  
try{ PAy7b7m~B  
URL url = new URL(siteInfoBean.getSSiteURL()); .h;X5q1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <p8>"~ R  
httpConnection.setRequestProperty("User-Agent","NetFox"); [E/^bM+  
F#\+.inO  
 B*Q  
int responseCode=httpConnection.getResponseCode(); \!'K#%]9  
if(responseCode>=400) +Ram%"Zwh  
{ b]5S9^=LI  
processErrorCode(responseCode); '5SO3/{b  
return -2; //-2 represent access is error %Z#[{yuFs  
} Ya,(J0l  
<e'l"3+9(  
vTYgWR,h  
String sHeader; }{ "RgT-qG  
M9sB2Ips<  
K/XUF#^B]  
for(int i=1;;i++) 3x~AaC.j  
{ :X- \!w\  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); #.~lt8F  
//Utility.log(in.readLine()); [fXC ;c1  
sHeader=httpConnection.getHeaderFieldKey(i); 05vu{>  
if(sHeader!=null) ou'|e"tI  
{ Ix|^c268o<  
if(sHeader.equals("Content-Length")) pB0Do6+{  
{ .2STBh.;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jQ\/R~)O  
break; I K Dh)Zm  
} OL$^7FB  
} fsVr<m  
else +N!!Z2  
break; 5v-o2  
} O7tL,)Vv  
} Nx4X1j?-n  
catch(IOException e){e.printStackTrace ();} [$(/H;  
catch(Exception e){e.printStackTrace ();} >CPoeIHK  
Pr^p ^s  
~m@w p  
Utility.log(nFileLength);  .)XJ-  
s$;IR c5!6  
aQhr$aH  
return nFileLength; rlVo}kc7:  
} i"C?6R  
^Dhu8C(  
&>o?0A6  
//保存下载信息(文件指针位置) "J6 aU  
private void write_nPos() {uMqd-Uu  
{ FUU/=)^P$  
try{ X~Vr}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >c:- ;(k  
output.writeInt(nStartPos.length); ='|HUxFi  
for(int i=0;i<nStartPos.length;i++) Z8Il3b*)  
{ T~'9p`IW  
// output.writeLong(nPos); vdN0YCXG  
output.writeLong(fileSplitterFetch.nStartPos); 66~]7w  
output.writeLong(fileSplitterFetch.nEndPos); Dhe ]f#d  
} -,#LTW<.  
output.close(); BHBMMjY5  
} k/ ZuFTN  
catch(IOException e){e.printStackTrace ();} yS:1F PA$_  
catch(Exception e){e.printStackTrace ();} 2Md'<.  
} IKV:J9  
ZIrJ"*QO=  
A?sU[b6_  
//读取保存的下载信息(文件指针位置) HR83{B21  
private void read_nPos() H/6GD,0  
{ pu*vFwZ  
try{ Y4|g^>{<ni  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); qP0_#l&  
int nCount = input.readInt(); j?n:"@!G/  
nStartPos = new long[nCount]; ,o)U9 <  
nEndPos = new long[nCount]; Q-GnNT7MB3  
for(int i=0;i<nStartPos.length;i++) hq^@t6!C\m  
{ pJ1Q~tI  
nStartPos = input.readLong(); 8QGj:3  
nEndPos = input.readLong(); |.Pl[y  
} 'qg q8  
input.close(); mjqVP.  
} /RmHG H!  
catch(IOException e){e.printStackTrace ();} _}B:SM  
catch(Exception e){e.printStackTrace ();} R?Or=W)i  
} ~:%rg H  
|cBpX+D  
*AU"FI> V  
private void processErrorCode(int nErrorCode) -cHX3UAEI  
{ ?geEq'  
System.err.println("Error Code : " + nErrorCode); ,\K1cW~U5  
} /U%Xs}A)  
S qQqG3F  
sm>Hkci%  
//停止文件下载 afMIqQ?  
public void siteStop() JDzk v%E^  
{ d>Z{TFY  
bStop = true; *?+maK{5+  
for(int i=0;i<nStartPos.length;i++) Y(]&j`%  
fileSplitterFetch.splitterStop(); ,1YnWy *  
#)BdN  
k+S 6)BQ7U  
} &,Xs=Lv mq  
} vx\h Njb  
//负责部分文件的抓取 X=p~`Ar M{  
**FileSplitterFetch.java -R;.Md_  
*/ WM}bM] oe  
package NetFox; k'BLos1W  
Ek,s6B)'d  
f9FsZD  
import java.io.*; hsQrHs'k  
import java.net.*; Tdr^~dcQ  
[-sE:O`yt  
[N/[7Q/y  
public class FileSplitterFetch extends Thread { u= K?K  
snBC +`-  
<'4DMZ-G  
String sURL; //File URL M,Px.@tw.  
long nStartPos; //File Snippet Start Position *s6MF{Ds  
long nEndPos; //File Snippet End Position pAV}hB  
int nThreadID; //Thread's ID T@]vjXd![  
boolean bDownOver = false; //Downing is over (r^IW{IndX  
boolean bStop = false; //Stop identical  /y,~?  
FileAccessI fileAccessI = null; //File Access interface '* +]&~b  
)]%GNdU  
k:w\4Oqd  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q*ZjOqj  
{ { A(= phN  
this.sURL = sURL; By@<N [I@  
this.nStartPos = nStart; +mP3 y~|-j  
this.nEndPos = nEnd; eP3)8QC  
nThreadID = id; d%9r"=/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 NdQXQa?,  
} H3.WAg[`  
$2^V#GWo  
*Df|D/,WE  
public void run() Y 1 i!  
{ i)0*J?l=  
while(nStartPos < nEndPos && !bStop) 'PlKCn`(w  
{ nYuZg6K  
 jK&kQ  
x]k^JPX  
try{ M)#R_(Q5{  
URL url = new URL(sURL); Ox&g#,@h  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R9yK"  
httpConnection.setRequestProperty("User-Agent","NetFox"); }tU<RvT  
String sProperty = "bytes="+nStartPos+"-"; %t\`20-1<  
httpConnection.setRequestProperty("RANGE",sProperty); VbtFM=Dg  
Utility.log(sProperty); #cQ[ vE)y  
vbQo8GFp}  
S[NV-)r=  
InputStream input = httpConnection.getInputStream(); oS$&jd  
//logResponseHead(httpConnection); +gOCl*L  
*kxk@(lT?  
6yF4%Sz9  
byte[] b = new byte[1024]; "_C^Bc  
int nRead; yi7-[W}  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) nrA}36E  
{ [6 !/  
nStartPos += fileAccessI.write(b,0,nRead); {61NLF\0H  
//if(nThreadID == 1) +6f5uMKUvs  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ''wWw(2O  
} -Tk~c1I#`  
jjz<V(Sk  
2u6N';jgZ  
Utility.log("Thread " + nThreadID + " is over!"); DnaG$a<  
bDownOver = true; Xt8;Pl  
//nPos = fileAccessI.write (b,0,nRead); 1(!!EcU_  
} Uz H)fB  
catch(Exception e){e.printStackTrace ();} q[q#cY:0  
} K I$?0O  
} i<1w*yu  
T{|'<KT  
P,~a'_w:|D  
//打印回应的头信息 qEf )TW(  
public void logResponseHead(HttpURLConnection con) 'mug,jM  
{ ,I@4)RSAH|  
for(int i=1;;i++) "^<:7_Y  
{ Qkk~{OuC  
String header=con.getHeaderFieldKey(i); :H\6wJ  
if(header!=null) z0HCmj9T  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); mw`%xID*  
Utility.log(header+" : "+con.getHeaderField(header)); 8R:H{)o~s}  
else `/]8C &u  
break; =X>3C"]  
} +&a2aEXF  
} ygUvO3Z  
0'|#Hi7@  
*H&a_s/{Nb  
public void splitterStop() Y.i<7pBt  
{ *D,+v!wG9  
bStop = true; '4FS.0*_  
} PQvq$|q  
3VA8K@QiRm  
S5v>WI^0h  
} Q_6./.GQ  
nUhD41GJ  
-j]r\EVKS  
/* `U!eh1*b  
**FileAccess.java ED"5y  
*//文件访问(定位,写) Y#{KGVT<  
package NetFox; ',6QL4qV/  
import java.io.*; M5exo   
R.|fc5_"+  
F>n<;<  
public class FileAccessI implements Serializable{ u;& `_=p  
4m#i4  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 < 5[wP)K@  
RandomAccessFile oSavedFile; =[t([DG  
long nPos; C+ r--"Z  
F.PD5%/$q  
.XURI#b  
public FileAccessI() throws IOException <pYGcVB9V  
{ U`:#+8h-}  
this("",0); 5:CC\!&QBV  
} 9qwVBu ;  
-1S+fUkiK/  
wXXv0OzK  
public FileAccessI(String sName,long nPos) throws IOException Xj+1]KRN  
{ |mk$W$h  
oSavedFile = new RandomAccessFile(sName,"rw"); j=dHgnVvj  
this.nPos = nPos; PM=I  
oSavedFile.seek(nPos); [JMz~~ F  
} }%$9nq3  
IOTHk+w  
0NpxqeIDY  
public synchronized int write(byte[] b,int nStart,int nLen) )/bt/,M&}  
{ S][: b  
int n = -1; : [aUpX=  
try{ A+Y>1-=JO  
oSavedFile.write(b,nStart,nLen); Lkk'y})/  
n = nLen; MZ+8wr/y  
} Gk799SDL  
catch(IOException e) t ~U&a9&Z  
{ fn#b3ee  
e.printStackTrace (); z~o%U&DO}  
} AZl|; y  
0[PP Vr:  
I.y|AQB  
return n; l+R-lsj  
} uA:;OM}  
N<Y-]xS  
vh?({A#>.E  
} }6C&N8 f  
dW8'$!@!!  
.__X[Mzth3  
/* b*dRNu  
**SiteInfoBean.java c 0!bn b  
*/ q* Ns]f'a  
package NetFox; ((EN&X,v  
(.%:Q0i1  
7ou2SL}k  
public class SiteInfoBean { |`qur5h`  
?PyI#G   
/o8`I m   
private String sSiteURL; //Site's URL GsqrKrbJ  
private String sFilePath; //Saved File's Path ttZ!P:H2  
private String sFileName; //Saved File's Name W.zA1S  
private int nSplitter; //Count of Splited Downloading File 4X#>;  
Pm+H!x,  
JsfbY^wz  
public SiteInfoBean() H -.3r  
{//nSplitter的缺省值为5 'OBA nE<.  
//default value of nSplitter is 5 K{M_ 4'\  
this("","","",5); @] )a  
} "-v9V7KCM  
g"# R>&P  
)F4er '  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .t"s>jq 1  
{ 'cH),~ z  
sSiteURL= sURL; vx!nC}f"k`  
sFilePath = sPath; (X>r_4W$  
sFileName = sName; :8Q6=K87  
this.nSplitter = nSpiltter; "vU:qwm  
!R{L`T0  
']Y:f)i#  
} T`a [~:  
/MQd[03]  
Am  kHVg  
public String getSSiteURL() C/!2q$  
{ ]>R`]U9*O  
return sSiteURL; xiA9X]FB  
} _6=6 b!hD  
.%WbXs  
x0Tb7y`  
public void setSSiteURL(String value) iKp4@6an  
{ Pb]s+1  
sSiteURL = value; N1#*~/sXh  
} <-}6X  
wQM(Lm#Q  
C+y:<oo)  
public String getSFilePath() y3;G<9K2c]  
{ ix7N q7!N  
return sFilePath; &)xoR4!2  
} bmt2~!  
ub,Sj{Mq"  
wG^{Jf&@$  
public void setSFilePath(String value) 5"XcVH4g  
{ oh& P Q{  
sFilePath = value; IWm|6@y  
} aeH 9:GQ6  
7|,5;  
InPq1AH  
public String getSFileName() ;"joebZ/  
{ E@ t~juF!  
return sFileName; ,6a'x~y<r  
} TmzEZ<} &7  
x,>@IEN7  
zpg*hlv  
public void setSFileName(String value) 9-bDgzk   
{ WNd(X}  
sFileName = value; RMLs(?e  
} DJrA@hm/Y  
s'} oVx]  
gtCd#t'(V  
public int getNSplitter() q7m-} mBN~  
{ !y4o^Su[  
return nSplitter; -fG;`N5U  
} O$#`he/jm  
ajkRL|^  
<k<  
public void setNSplitter(int nCount) v C><N  
{ lv$tp,+  
nSplitter = nCount; AO8`ItNZdT  
} ]<z>YyBA  
} RE *UIh*O  
pmQ9i A@=  
(zgXhx_!D  
/* 9.1%T06$  
**Utility.java =GnDiI  
*/ q1NAKcA<U  
package NetFox; RUO,tB|(_;  
6I_W4`<VeZ  
dk{yx(Ty  
public class Utility { ->K*r\T  
4V<s"  
|3"'>* J  
public Utility() BhdJ/C^  
{ kS=OX5  
EkjO4=~UC  
roW8 4x  
} s:;!QIC5jo  
Ds0^/bYp&  
//线程睡眠  b.C!4^  
public static void sleep(int nSecond) ;uDH&3W  
{ }v@w(*)h:  
try{ #,!.e  
Thread.sleep(nSecond); (B,CL222x  
} [",W TZ:  
catch(Exception e) =wI ,H@  
{ ~{U~9v^v (  
e.printStackTrace (); JsVW:8QO~  
} PN0:,.4  
} A9$q;8= <  
qBKIl= ne  
//日志 ETjlq]@j  
public static void log(String sMsg) vxZz9+UbF  
{ 2hmV 1gj  
System.err.println(sMsg); "{L%5:H@  
} AP/5, M<  
N55;oj_K  
Ngh9+b6[  
public static void log(int sMsg) Q@ /wn  
{ !cp ,OrO\  
System.err.println(sMsg); -b r/  
} e[w)U{|40  
} "E 8-76n  
'iUfr@  
V:My1R0  
/* <E$5LP;:  
**TestMethod.java 'S@C,x%2,  
*/ Qmzj1e$6x  
package NetFox; >!`T=(u!  
e)7[weGN  
,C(")?4aJ  
public class TestMethod { &``;1/J*W  
_YO` x  
@ZD1HA,h"  
public TestMethod() *vUKh^="  
{ ///xx/weblogic60b2_win.exe 0(:"q!h  
try{ />K$_T/]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); &[qL l  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }UQBaqDH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [S-NGip  
fileFetch.start(); rv:,Os_  
} $&k zix  
catch(Exception e){e.printStackTrace ();} vL\wA_z"<H  
XSn^$$S  
GfL}f9  
} r$R(4q:  
(Dq3e9fX  
f>-OwL($P  
public static void main(String[] args) 73 D|gF*  
{ QjF.U8  
new TestMethod(); OHM.xw*?.  
} &{/ `Q ,  
} p>|;fS\`@}  
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