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http断点续传简单实现(java)

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/* {^\+iK4bS  
**SiteFileFetch.java }bdmomV  
*/ W-?()dX{  
package NetFox; E5I"%9X0H  
import java.io.*; 7 "20hAd  
import java.net.*; = kJ,%\E`  
:h\Q;?  
?o81E2TJO  
public class SiteFileFetch extends Thread { gW)3e1a  
a@@)6FM  
* +"9%&?  
SiteInfoBean siteInfoBean = null; //文件信息Bean 2jR r,Nl  
long[] nStartPos; //开始位置 /OLFcxEWh  
long[] nEndPos; //结束位置 cx&>#8s&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 }o(zj=7  
long nFileLength; //文件长度 MvK !u  
boolean bFirst = true; //是否第一次取文件 PIu1+k.r?  
boolean bStop = false; //停止标志 yku5SEJ\  
File tmpFile; //文件下载的临时信息 0 q} *S~  
DataOutputStream output; //输出到文件的输出流 vms|x wb  
$~VRza 8Q  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) K 1 a\b"  
public SiteFileFetch(SiteInfoBean bean) throws IOException lij.N) E  
{ bdC8zDD  
siteInfoBean = bean; mS(fgq6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); UNom-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ta(Y:*Ri  
if(tmpFile.exists ()) 9Uj $K>:  
{ &PYK8}pBk3  
bFirst = false; 3I)VHMC  
read_nPos(); D~hg$XzK  
} ="Ho%*@6  
else *AO,^R&e.  
{ gy#/D& N[  
nStartPos = new long[bean.getNSplitter()]; 3RYpJAH  
nEndPos = new long[bean.getNSplitter()]; u%}nw :>  
} p "n$!ilbm  
fGUE<l  
>O*IQ[r-  
Cs9.&Y  
} 8u6:=fxb  
VH9dleZ  
^l9N48]|?  
public void run() D8Ykg >B;&  
{ 95 ;x=ju  
//获得文件长度 $ M`hh{ -  
//分割文件 M?Dfu .t  
//实例FileSplitterFetch DI:]GED" =  
//启动FileSplitterFetch线程 QZ6D7t Uc8  
//等待子线程返回 pR(jglm7-  
try{ _FH`pv  
if(bFirst) B8f8w)m  
{ `|{-+m  
nFileLength = getFileSize(); _P0T)-X\(  
if(nFileLength == -1) "e.jZcN*  
{ B* ?]H*K  
System.err.println("File Length is not known!"); DJ'zz&K  
} AK'[c+2[  
else if(nFileLength == -2) Fq |Ni$  
{ B:'J `M"N  
System.err.println("File is not access!"); 41`n1:-]  
} R=gb'  
else LAB=Vp1y3[  
{ ,?>s>bHV  
for(int i=0;i<nStartPos.length;i++) X:HacYqtC  
{ >/l? g5{  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); i,>khc  
} hIy~B['  
for(int i=0;i<nEndPos.length-1;i++) &J[:awQX  
{ 63\/ * NNB  
nEndPos = nStartPos[i+1]; %zG;Q@  
} w65K[l;2  
nEndPos[nEndPos.length-1] = nFileLength; 1S{D6#bE  
} J]{QB^?  
} ]^h]t~  
 Uwf +  
yv t.  
//启动子线程 L 6 c 40  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; > V-A;S:  
for(int i=0;i<nStartPos.length;i++) O_ `VV*  
{ } Yb[   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^E;kgED5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), pMw*9s X  
nStartPos,nEndPos,i); IwQ"eUnK  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); eD,.~Y#?=  
fileSplitterFetch.start(); NjVYLn<.r  
} FHj" nB  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ur)9x^y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Of*Pw[vD  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4ezEW|S  
nEndPos = " + nFileLength); _ TiuY  
// fileSplitterFetch[nPos.length-1].start(); wH>a~C:  
VCV"S>aVf  
aS{|uE]  
//等待子线程结束 l3Xfc2~ 2  
//int count = 0; 7%5z p|3  
//是否结束while循环 g%sluT[#  
boolean breakWhile = false; k.uH~S_  
GWZ }7ake  
uxXBEq;  
while(!bStop) @5N]ZQ9  
{ smlpD3?va  
write_nPos(); BF\XEm?!  
Utility.sleep(500); )(bW#-  
breakWhile = true; h;p>o75O  
YWe{juXSw  
mk;&yh  
for(int i=0;i<nStartPos.length;i++) dG@%jD)  
{ %RTBV9LIXr  
if(!fileSplitterFetch.bDownOver) Lt u'W22  
{ ?9!6%]2D  
breakWhile = false; CyJEY-  
break; 95ZyP!  
} T$>WE= Y  
} 9]k @Q_  
if(breakWhile) }JF13beU  
break; 3 }duG/  
[$mHv,~  
/KFfU1  
//count++; *:Y%HAy*  
//if(count>4) RSfQNc9Z  
// siteStop(); 2GP=&K/A  
} [)H&'5 +F  
,|3MG",@@h  
D9<!mH  
System.err.println("文件下载结束!"); N4v~;;@(  
} Y\D!/T  
catch(Exception e){e.printStackTrace ();} n`#tKwWHYx  
} N(; 1o.~  
,vr? 2k  
?:vv50  
//获得文件长度 RiDJ> 6S  
public long getFileSize() Lf16j*}-Q  
{ Xnt~]k\"  
int nFileLength = -1; G? ])o5  
try{ <`.X$r*  
URL url = new URL(siteInfoBean.getSSiteURL()); o)h_H;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P@Hs`=  
httpConnection.setRequestProperty("User-Agent","NetFox"); w^Sz#_2  
CNih6R  
#*D)Q/k  
int responseCode=httpConnection.getResponseCode(); =b%MXT  
if(responseCode>=400) 1a?!@g )  
{ o2nv+fy W  
processErrorCode(responseCode); o*b] p-  
return -2; //-2 represent access is error *QpMF/<?  
} SON-Z"v  
+NeOSQSj  
\.0^n3y  
String sHeader; WYHQ?  
I5`4Al  
L5Ebc#  
for(int i=1;;i++) SzAJ2:qhl  
{ B~6&{7 xc%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |9uOUE  
//Utility.log(in.readLine()); 0@[$lv;OS  
sHeader=httpConnection.getHeaderFieldKey(i); -f3p U:G8  
if(sHeader!=null) ?iw!OoZ`  
{ o m^0}$V  
if(sHeader.equals("Content-Length")) A#K14Ayr  
{ \9cbI3rGz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ERUz3mjA/  
break; ]_Vx{oT7  
} ~Y`ldL  
} .7Dtm<K#  
else lsJSYJG&  
break; ojafy}  
} @D.}\(  
} tWJZoD6}h  
catch(IOException e){e.printStackTrace ();} 2POXj!N  
catch(Exception e){e.printStackTrace ();} 2V"B:X\  
A}BVep@D  
+O"!qAiK  
Utility.log(nFileLength); 4-? C>  
.~)q};Z  
Cl5uS%g  
return nFileLength; <->{  
} o15-ZzE-  
KxI&G%z  
; ^*}#X d  
//保存下载信息(文件指针位置) y0{u<"t%w  
private void write_nPos() cbNTj$'b2u  
{ q]\:P.x!>  
try{ fX(3H1$"  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +Jlay1U&  
output.writeInt(nStartPos.length); AV:h BoO  
for(int i=0;i<nStartPos.length;i++) O_2pIbh  
{ ^?-:'<4q$  
// output.writeLong(nPos); Ye\rB\-  
output.writeLong(fileSplitterFetch.nStartPos); Y#]+Tm (+  
output.writeLong(fileSplitterFetch.nEndPos); -j+UMlkB  
} 4~ q5,^kgB  
output.close(); pf2[ , v/  
} b[sx_b  
catch(IOException e){e.printStackTrace ();} J}*,HT*  
catch(Exception e){e.printStackTrace ();} qaqBOHI6G  
} z#8~iF1  
'OE&/ C [  
p?{Xu4(  
//读取保存的下载信息(文件指针位置) ED2a}Tt>Z  
private void read_nPos() O)C\v F#  
{ zE336  
try{ hP=WFD&  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); H~oail{EQ  
int nCount = input.readInt(); xj<Rp|7&  
nStartPos = new long[nCount]; Um }  
nEndPos = new long[nCount]; 5Iy|BRU(%  
for(int i=0;i<nStartPos.length;i++) 2n,*Nd`  
{ ~De"?  
nStartPos = input.readLong(); FG PB:  
nEndPos = input.readLong(); m-%E-nr  
} wa(8Hl|Y  
input.close(); '@cANGg7[  
} kj|6iG  
catch(IOException e){e.printStackTrace ();} 6 +Sxr  
catch(Exception e){e.printStackTrace ();} z F_M*8=  
} BIb4h   
$Ad{Z  
N@;?CKU  
private void processErrorCode(int nErrorCode) -<c=US  
{ jTf@l?|  
System.err.println("Error Code : " + nErrorCode); F;>V>" edl  
} u~r=)His  
K#l:wH _  
@+;$jRwq  
//停止文件下载 @v$Y7mw3D  
public void siteStop() ;5wn67'  
{ v:EB*3n5  
bStop = true; :Gv1?M  
for(int i=0;i<nStartPos.length;i++) *w$W2I>b7  
fileSplitterFetch.splitterStop(); w:??h4lt  
NWP5If|'X  
LnFdhrB@x  
} 214Ml0/%  
} ,ZKr .`B  
//负责部分文件的抓取 D_?K"E=fw  
**FileSplitterFetch.java MV! {j;g1<  
*/ ,f kcp]}  
package NetFox; &w4?)#  
V@\gS"Tu  
'QG xd!4  
import java.io.*; \Lq h j  
import java.net.*; Y}@&h!  
 |$+3a  
ZkgV_<M|  
public class FileSplitterFetch extends Thread { G=)i{oC  
:fKl]XO  
<i<J^-W  
String sURL; //File URL :KH g&ZX7  
long nStartPos; //File Snippet Start Position \/E>4)MDy  
long nEndPos; //File Snippet End Position B*qi_{Gp  
int nThreadID; //Thread's ID Pih tf4i  
boolean bDownOver = false; //Downing is over lNNv|YiL  
boolean bStop = false; //Stop identical sD<a+Lw}x  
FileAccessI fileAccessI = null; //File Access interface ZjT,pOSyb  
`+`Z7  
I\hh8abAp  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ?M$.+V{a  
{ 3NZK*!@ '  
this.sURL = sURL; Twh!X*uQ  
this.nStartPos = nStart; @)IjNplYkw  
this.nEndPos = nEnd; r}Ohkr  
nThreadID = id; c@YI;HS_g  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 gep;{G}  
} *v?`<)P#  
du+y5dw  
k2E0/ @f{k  
public void run() W"724fwu&  
{ 5&xB6|k  
while(nStartPos < nEndPos && !bStop) t4{rb, }W  
{ &6DMk-  
1h(0IjG8  
?xK8#  
try{ 1m+p;T$  
URL url = new URL(sURL); ;g8R4!J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); so^lb?g  
httpConnection.setRequestProperty("User-Agent","NetFox"); >82@Q^O  
String sProperty = "bytes="+nStartPos+"-"; WJ)z6m]  
httpConnection.setRequestProperty("RANGE",sProperty); w'L\?pI  
Utility.log(sProperty); mrTlXXz  
85lCj-cs  
xrlmKSPa  
InputStream input = httpConnection.getInputStream(); =nz}XH%=  
//logResponseHead(httpConnection); QS0:@.}$E)  
V=)_yIS  
Gb"r|(!  
byte[] b = new byte[1024]; l|xZk4@_uE  
int nRead; /`9sPR6e  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) z+ s6)Ad  
{ sfLMk E  
nStartPos += fileAccessI.write(b,0,nRead); 4f@o mAM  
//if(nThreadID == 1) ^<;V]cY`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ,_|]Ufr!a  
} U0=]  
U93}-){m  
_\=`6`b)  
Utility.log("Thread " + nThreadID + " is over!"); Gn&-X]Rrl  
bDownOver = true; uC.K<jD%  
//nPos = fileAccessI.write (b,0,nRead); Xf0M:\w=M  
} jQk*8   
catch(Exception e){e.printStackTrace ();} pqUCqo!m\  
} "~E[)^ANxD  
} ,PlO8;5]  
syk!7zfK  
`L:CA5sBud  
//打印回应的头信息 )X04K~6lY  
public void logResponseHead(HttpURLConnection con) :z}MIuf  
{ El<]b7  
for(int i=1;;i++) Rfn9s(m  
{ 0MV>"aV  
String header=con.getHeaderFieldKey(i); #G|qD  
if(header!=null) 7:A x(El  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;_8#f%Y#R  
Utility.log(header+" : "+con.getHeaderField(header)); VQY&g;[d  
else (Lo%9HZ1Mx  
break; e'~Zo9`r6  
} 5'0xz.)!  
} X_qf"|i  
g wz7krUTe  
qL5{f(U4<  
public void splitterStop() Jm|+-F@I  
{ wg ^sGKN  
bStop = true; b'P eH\h{  
} =PUt&`1.a  
j lp:lX  
u4m,'XR  
} 3:5 &Aa!  
}YjX3|8zL=  
> *@y8u*  
/* (*1v\Q  
**FileAccess.java |nbf'  
*//文件访问(定位,写) =81@ o,1w  
package NetFox; N+zKr/  
import java.io.*; : q ti  
ii%+jdi.  
RbCPmiZcH  
public class FileAccessI implements Serializable{ u4.ngjJ  
*"WDb|PBb  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 J\J?yo 6  
RandomAccessFile oSavedFile; 7uT:b!^f[  
long nPos; a UxGzMZ  
Kh(ZU^{n  
.U"8mP=&  
public FileAccessI() throws IOException 7~9S 9  
{ I96C i2)m  
this("",0); !h(|\" }  
} \(VTt|}By$  
I6j$X6u  
,QC{3i~  
public FileAccessI(String sName,long nPos) throws IOException XGJj3-eW {  
{ 76wc,+  
oSavedFile = new RandomAccessFile(sName,"rw"); l_EM8pL,f  
this.nPos = nPos; H_EB1"C;\  
oSavedFile.seek(nPos);  |?Frj  
} ( xXGSx  
0ge$ p,  
\=+b}mKV m  
public synchronized int write(byte[] b,int nStart,int nLen) )foq),2  
{ 6&DX] [G  
int n = -1; i O/K nH  
try{ 4Y,R-+f  
oSavedFile.write(b,nStart,nLen); _2k]3z?  
n = nLen; 1^ _U;O:I  
} iv?gZg   
catch(IOException e) 4 SHU  
{ Rop'e8Q  
e.printStackTrace (); ZIPl7tTw  
} _ ):d`O e  
[vMvV4,  
.fN"@l  
return n; @mE)|.f  
} ix W@7m  
t| 9 GS|  
|u0( t,T  
} AtU v71D:  
( Fynok  
QU%I43  
/* YX=2jI  
**SiteInfoBean.java BBH0OiV=  
*/ +j(d| L\  
package NetFox; j=*l$RG  
p/JL9@:'  
SrFS#  
public class SiteInfoBean { ?+g`HTY u  
S!Omy:=;i  
]?Fi$3Lm  
private String sSiteURL; //Site's URL K+Z+wA?  
private String sFilePath; //Saved File's Path )uK{uYQl  
private String sFileName; //Saved File's Name S-7'it!1  
private int nSplitter; //Count of Splited Downloading File `W dD8E  
5k6mmiaKk  
gXonF'  
public SiteInfoBean() R)F;py8)I  
{//nSplitter的缺省值为5 >w-;Z>3Q@  
//default value of nSplitter is 5 j. *VJazb;  
this("","","",5); KhCzD[tf  
} TMs,j!w?I  
lc2i`MC  
Z4A!U~  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) W%.v.0   
{ L KCb_9  
sSiteURL= sURL; U\veOQ;mW  
sFilePath = sPath; PqyA1  
sFileName = sName; J4"mK1N(  
this.nSplitter = nSpiltter; -+7uy.@cS  
?lbH02P{v  
;<$H)`*  
} !/^-;o7  
7_.11$E=H  
,g7.rEA  
public String getSSiteURL() a-"k/P#  
{ "V>R9dO{"!  
return sSiteURL; q}/WQ]p} <  
} uKz,SqX  
i `s|,"0o  
H;U)b{  
public void setSSiteURL(String value) &?uz`pv2  
{ P y>{t4;S  
sSiteURL = value; `+zWu 55;  
} >iOzl wmG  
/0W9g  
aWwPvd3  
public String getSFilePath() v~T7`  
{ :Gu+m  
return sFilePath; qS/V"|G(  
} $`8Ar,Xz`  
1=|7mehL%  
{^ m(,K_  
public void setSFilePath(String value) ?_oF:*~\  
{ 277ASCWLkU  
sFilePath = value; UWZa|I~:J  
} e/*$^i+S  
|.F  
op"$E1+  
public String getSFileName() !" JfOu  
{ :-iMdtm  
return sFileName; Ja]?&j  
} t4q ej  
'DCFezdf3  
5jgdbHog]  
public void setSFileName(String value) j}BHj.YuP  
{ { F'Kk\f%:  
sFileName = value; ?\U!huu  
} yJsH=5A  
&f>eQ S=(  
l{:a1^[>y  
public int getNSplitter() 8K;Y2 #  
{ GyW.2  
return nSplitter; SR^_cpZoi  
} D?~8za`5  
aZet0?Qr  
Aj9Ji"18za  
public void setNSplitter(int nCount) x$wd O  
{ [xfaj'j=@  
nSplitter = nCount; ewuXpv%vwW  
} ="%W2  
} `gpQW~*R-;  
ExSO|g]%  
Q \]Xm>  
/* -/ x W  
**Utility.java uNHdpni  
*/ TZ;p0^(  
package NetFox; !Y<oN~<%)  
Uw/l>\  
vBvNu<v7te  
public class Utility { 1AHx"e,;L  
g7CXlT0Q6  
W%e_~$H0  
public Utility() Sf/q2/r?6[  
{ x|0:P sE  
_TUt9}  
$&Kq*m 0g  
} kvGCbRC  
'r} zY-FM`  
//线程睡眠 <w>/^|]#  
public static void sleep(int nSecond) ?Pwx~[<1""  
{ LF?P> 1%-  
try{ Sd))vS^g  
Thread.sleep(nSecond); w?mEuXc  
} F52B~@ .  
catch(Exception e) _Mc>W0'5@  
{ "BVdPSDBk  
e.printStackTrace (); xM s]Hs  
} h(B,d,q"  
} pi@Xkw  
Ogg#jx(4  
//日志 /%n`V  
public static void log(String sMsg) ~~F2Ij  
{ I\Glc=T*  
System.err.println(sMsg); ;pJ2V2 g8  
} aF8k/$u  
/}5B&TZ=(3  
 T7$S_  
public static void log(int sMsg) k$Rnj`*^  
{ wU`!B<,j  
System.err.println(sMsg); yg;_.4TpIO  
} Q0_>'sEM  
} Ybg- "w  
yPu4T6Vv  
( 0Naf  
/* J?n<ydZSH  
**TestMethod.java R^MiP|?ZH  
*/ f+Dn9t  
package NetFox; w7-WUvxl  
XD-^w_  
,xths3.K  
public class TestMethod { 5IqQ|/m<6  
fT Y/4(  
!q4x~G0d  
public TestMethod() % do1i W  
{ ///xx/weblogic60b2_win.exe h4fLl3%H  
try{ \k.vN@K#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~ eN8|SR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); C:\(~D *GS  
SiteFileFetch fileFetch = new SiteFileFetch(bean); $v} <'  
fileFetch.start(); Ulqh@CE)  
} ?M6ag_h3  
catch(Exception e){e.printStackTrace ();} ujgLJ77  
qJ8-9^E,L  
oP,9#FC|(  
} R9r+kj_  
`_ (~ Ud  
> %*B`oqo  
public static void main(String[] args) Vm8D"I5i  
{ lQ*eH10H  
new TestMethod(); dEp/dd~(&  
} Jm(ixekp  
} =qoRS0Qa  
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