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http断点续传简单实现(java)

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/* Xy5s^82?  
**SiteFileFetch.java <uk1?Q g  
*/ Z!&Rr~i <  
package NetFox; 16EVl~LN  
import java.io.*; u=NS sTP&  
import java.net.*; "ZHtR/;  
dg7=X{=9jv  
5P h X"7  
public class SiteFileFetch extends Thread { h~,JdDV8l*  
-/dEsgO  
#4h+j%y[H  
SiteInfoBean siteInfoBean = null; //文件信息Bean omf  Rs  
long[] nStartPos; //开始位置 4YMX|1wd)  
long[] nEndPos; //结束位置 sz):oea@f@  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 MfBdNdox7  
long nFileLength; //文件长度 HygY>s+3[  
boolean bFirst = true; //是否第一次取文件 tPyyZ#,  
boolean bStop = false; //停止标志 O:/y Ac`  
File tmpFile; //文件下载的临时信息 E%TpJl'U  
DataOutputStream output; //输出到文件的输出流 u%dKig  
` C+HE$B  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) rJ'I>Q~x6  
public SiteFileFetch(SiteInfoBean bean) throws IOException Hv<'dt$|  
{ }^K/?dM  
siteInfoBean = bean; |m?vVLq  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); tAFti+Qb  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -(JUd4#  
if(tmpFile.exists ()) Uo_tUp_Q  
{ tNmy& nsA  
bFirst = false; oXt,e   
read_nPos(); X7|.T0{=x  
} 5lJ )(|_  
else TE-;X,gDV_  
{ x q-$\#O  
nStartPos = new long[bean.getNSplitter()]; ftavbNR`W  
nEndPos = new long[bean.getNSplitter()]; &yz&LNn'  
} *NSlo^R-[  
>1irSUj"~  
<B&R6<]T  
2$zU&p7sV  
} dj[apuiF  
w.+Eyu_I\  
8C.!V =@\  
public void run() "] -],K  
{ IdRdW{o  
//获得文件长度 I/COqU7~  
//分割文件 xwzT#DXGJ  
//实例FileSplitterFetch r<L#q)]  
//启动FileSplitterFetch线程 8<)$z?K   
//等待子线程返回 qMS}t3X  
try{ 8]0:1 {@  
if(bFirst) %bX0 mN  
{ \w )?SVp  
nFileLength = getFileSize(); ,i ++fOnQ  
if(nFileLength == -1) =!-5+I#e  
{ 2neRJ  
System.err.println("File Length is not known!"); Q)Dwq?  
} Ha ZFxh-(  
else if(nFileLength == -2) mR":z|6  
{ Gbd?%{Xc-  
System.err.println("File is not access!"); T }uE0Z,  
} uJ'9R`E ]1  
else bGh0<r7R  
{ `.k5v7!o  
for(int i=0;i<nStartPos.length;i++) qCJ=Z  
{ VvgN3e[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); U=o Z.\  
} U %:c],Fk  
for(int i=0;i<nEndPos.length-1;i++) ^)cM&Bx t%  
{ l6B.6 '4)w  
nEndPos = nStartPos[i+1]; &R\XUxI  
} .{N\<01  
nEndPos[nEndPos.length-1] = nFileLength; x9`ZO< L$  
} K M]Wl_z  
} ~{ .,8jE  
eECj_eH-  
wd`R4CKhP]  
//启动子线程 `QCD$=  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; f0F#Yi{fw  
for(int i=0;i<nStartPos.length;i++) "<dN9l>  
{ >7FSH"8[,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $u,G Vq~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [oHOHp/V  
nStartPos,nEndPos,i); Pt3[|4L  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); dt.-C_MO  
fileSplitterFetch.start(); >DmRP7v   
} jg^^\n  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), anitqy#E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0N1' $K$\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", qi[(*bFK7  
nEndPos = " + nFileLength); xucIjPi]  
// fileSplitterFetch[nPos.length-1].start(); s#Q _Gu  
wG6FS  
}Ch[|D=Wd6  
//等待子线程结束 3z$\&& BR  
//int count = 0; NQ3|\<Wt  
//是否结束while循环 .??rqaZ=  
boolean breakWhile = false; - coy@S=.'  
$U mE  
B(E tXB9  
while(!bStop)  bn|DRy  
{ wO\!xW:  
write_nPos(); /op/g]O}  
Utility.sleep(500); 'v`~(9'Rcj  
breakWhile = true; .kzms  
6NKF'zh  
[EcV\.  
for(int i=0;i<nStartPos.length;i++) 6 cr^<]v!  
{ !%)L&W_  
if(!fileSplitterFetch.bDownOver) |<2JQ[]  
{ HO G=c!b  
breakWhile = false; A&?WP\_z  
break; E- [:. &  
} Bzwx0c2VY8  
} qFGB'mIrFz  
if(breakWhile) #s/{u RYQ  
break; zZw@c?  
o|BFvhg  
%!W 6<ioW  
//count++; ]qF<Zw7  
//if(count>4) ]b!R-G!gV  
// siteStop(); sF, uIr/  
} L)=8mF.  
c[6zX#{`  
A1Ibx|K  
System.err.println("文件下载结束!"); SSo~.)J  
} .w=:+msL{(  
catch(Exception e){e.printStackTrace ();} }$&);7(w  
} <(ubZ  
" Tw0a!  
/:Rn"0   
//获得文件长度 Udg & eEF  
public long getFileSize() t P At?  
{ o7hH9iY  
int nFileLength = -1; h7)VJY  
try{ X~`.}  
URL url = new URL(siteInfoBean.getSSiteURL()); 8dYk3 sk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); oT$(<$&<  
httpConnection.setRequestProperty("User-Agent","NetFox"); Bl:{p>-q  
S]Sp Z8  
nDwq!LEx%5  
int responseCode=httpConnection.getResponseCode(); 3/ yt*cr  
if(responseCode>=400) `mh-pBVD1  
{ $ $W{HsX  
processErrorCode(responseCode); gizmJ:<  
return -2; //-2 represent access is error )<m=YI ;<  
} Mt]=v}z  
JuKk"tr~RB  
I%.jc2kK  
String sHeader; )UxQf37  
f]{1ZU%4  
!- Cs?  
for(int i=1;;i++) "P>$=X~Zi  
{ 2D\x-!l/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z{8exym  
//Utility.log(in.readLine()); dlU JYI  
sHeader=httpConnection.getHeaderFieldKey(i); '2Mjz6mBDA  
if(sHeader!=null) -k|g04Q?  
{ ^!-E`<jW8  
if(sHeader.equals("Content-Length")) ;C7BoHB9  
{ \#IJ=+z   
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); t1*BWY  
break; /\oyPD`((  
} gdkLPZ<<  
} ~_/<PIm  
else (mOqv9pn  
break; 5yO#N2jY\  
} oX=*MEfX  
} =DQdPA\K  
catch(IOException e){e.printStackTrace ();} ^=heen<S%  
catch(Exception e){e.printStackTrace ();} xIq"[?m  
6qmo ZAg  
hSLwiX~  
Utility.log(nFileLength); CrQA :_Z(7  
@[[C s*-  
"`8H:y  
return nFileLength; Q T0IW(A  
} JaB tX'  
P_^ |KEz  
 8E.5k@  
//保存下载信息(文件指针位置) !)l%EJngL  
private void write_nPos() 4P-'(4I)  
{ /o}0oo5B  
try{ s$+: F$Y0  
output = new DataOutputStream(new FileOutputStream(tmpFile)); D KMbs   
output.writeInt(nStartPos.length); r~Is,.zZ}  
for(int i=0;i<nStartPos.length;i++) C7c|\T  
{ 1Q2k>q8  
// output.writeLong(nPos); 2+r )VF:  
output.writeLong(fileSplitterFetch.nStartPos); X<@y*?D9D  
output.writeLong(fileSplitterFetch.nEndPos); $.x?in|_  
} ~[ ks|  
output.close(); 04T*\G^:=  
} }GU6Q|s[u[  
catch(IOException e){e.printStackTrace ();} $'I$n  
catch(Exception e){e.printStackTrace ();} "*H'bzK  
} A=YEY n  
:b3l J-dB  
l52n/w#qFB  
//读取保存的下载信息(文件指针位置) sLpCWIy  
private void read_nPos() #mz,HK0|aC  
{ f >, Qhl  
try{ 4- ?`#  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |Bf:pG!  
int nCount = input.readInt(); Stp*JU  
nStartPos = new long[nCount]; =LeVJGF  
nEndPos = new long[nCount]; z6>ZV6(d2^  
for(int i=0;i<nStartPos.length;i++) tRrY)eElS  
{ l4BO@   
nStartPos = input.readLong(); Xta>  
nEndPos = input.readLong(); aK=3`q  
} qKb- aP-  
input.close(); /IQ-|Qkg  
} 3lrZ-k+S{  
catch(IOException e){e.printStackTrace ();} N~K)0RETn  
catch(Exception e){e.printStackTrace ();} Gv2./<{#  
} X-) ]lAP  
@W5hrei  
3x;y}:wQa  
private void processErrorCode(int nErrorCode) zZjLt1  
{ jX8C2}j  
System.err.println("Error Code : " + nErrorCode); YPJx/@Z`  
} $}"Wta  
%K f . F  
z%gtV'  
//停止文件下载 hm} :Me$[)  
public void siteStop() UFY~D"% /  
{ 1NHoIX  
bStop = true; GbrPtu2{@V  
for(int i=0;i<nStartPos.length;i++) qYiK bzy  
fileSplitterFetch.splitterStop(); XTXo xZ#w  
 3usA  
$Aoqtz d\  
} 4JQ`&:?r  
} O0*L9C/Q  
//负责部分文件的抓取 byxehJ6[V  
**FileSplitterFetch.java )B5gs%u]  
*/ .p*D[o2 9  
package NetFox; d`][1rZk  
6XCX#4'i%  
nXaX=  
import java.io.*; d"`>&8*  
import java.net.*; v.&*z48  
o*ED!y7  
Lj* =*V  
public class FileSplitterFetch extends Thread {  p:>?  
8PVs!?Nne  
Dj&bHC5%  
String sURL; //File URL |}y}o:(  
long nStartPos; //File Snippet Start Position W%ZU& YBc  
long nEndPos; //File Snippet End Position Uht:wEr  
int nThreadID; //Thread's ID |}.B!vg(4  
boolean bDownOver = false; //Downing is over wgP3&4cSUc  
boolean bStop = false; //Stop identical T@.m^|~  
FileAccessI fileAccessI = null; //File Access interface ={vtfgxl  
f]65iE?x  
x9 L\"  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g;Q^_4@  
{ >w;W& [  
this.sURL = sURL; !PTbR4s  
this.nStartPos = nStart; &{{f|o=u.  
this.nEndPos = nEnd; 0c6AQP"=V  
nThreadID = id; i4C b&h^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w3UJw  
} 6Tmb@<I_  
#IA(*oM  
mzR @P$:36  
public void run() ;//q jo  
{ Y[]t_o)  
while(nStartPos < nEndPos && !bStop) <?}g[]i  
{ K1nwv"  
pg`;)@  
6_><W"r:]  
try{  +6-!o,(  
URL url = new URL(sURL); 1OeDWEcB  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /kVc7 LC  
httpConnection.setRequestProperty("User-Agent","NetFox"); n=MYv(Pp}  
String sProperty = "bytes="+nStartPos+"-"; )BrqE uX@"  
httpConnection.setRequestProperty("RANGE",sProperty); na; ^/_U@  
Utility.log(sProperty); L,GtIZkE  
}=4".V`-o  
BJr Nbo;T  
InputStream input = httpConnection.getInputStream(); f|E'eFrFk  
//logResponseHead(httpConnection); `t2! M\)  
`Pbn  
\./2Qc,  
byte[] b = new byte[1024]; d7gSkna`5c  
int nRead; ^/,yZ:  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &N nMz9  
{ ]gk1h=Y~h  
nStartPos += fileAccessI.write(b,0,nRead); !g:UM R  
//if(nThreadID == 1) =MLL-a1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )j*qGsOg  
} }H.vH  
j(2T,WM  
 e:R[  
Utility.log("Thread " + nThreadID + " is over!"); c:TP7"vG  
bDownOver = true; (k45k/PAP  
//nPos = fileAccessI.write (b,0,nRead); x{5*%}lX8  
} ^Y |s^N  
catch(Exception e){e.printStackTrace ();} zb$U'D_ -f  
} J n/=v\K@  
} np(<Ap r  
G8'3.;"W5  
D._r@~o  
//打印回应的头信息 w:v:znQrW  
public void logResponseHead(HttpURLConnection con) u>#'Y+7  
{ ;zODp+4@Q  
for(int i=1;;i++) (%, '  
{ #n r1- sf|  
String header=con.getHeaderFieldKey(i); Qg=~n:j  
if(header!=null) H;ib3?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2ra4t]f6  
Utility.log(header+" : "+con.getHeaderField(header)); \PJ89u0  
else $_kU)<e3  
break; ^lj>v}4fkW  
} RqR  X  
} g=Jfp$*[  
g^FH[(P[G  
ipG+qj/=  
public void splitterStop() AaVlNjB  
{ 'z/hj>B<  
bStop = true; \)*qW[C$a  
} k$c!J'qL&  
Dlp::U*N'  
L\I/2aiE  
} bql6Z1l  
"^`AS"z'  
|EunDb[Y  
/* f{0PLFj  
**FileAccess.java 1|--Xnv  
*//文件访问(定位,写) /DCUwg=0  
package NetFox; 9L,T@#7  
import java.io.*; KC'{>rt7  
7JbrIdDl|  
,O(uuq  
public class FileAccessI implements Serializable{ %|Vq"MW,I  
xp = ]J UQ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 CAfG3;  
RandomAccessFile oSavedFile; G8VWx&RE  
long nPos; PYGHN T  
u-,=C/iU  
G6FknYj  
public FileAccessI() throws IOException <#sK~G  
{ $|KbjpQ  
this("",0); v2NzPzzyb  
} t$b`Am  
X(~NpLR  
tP3Upw"U  
public FileAccessI(String sName,long nPos) throws IOException :7gIm|2"]  
{ %5b2vrg~*  
oSavedFile = new RandomAccessFile(sName,"rw"); JdE=!~\8  
this.nPos = nPos; $ |AxQQ%f  
oSavedFile.seek(nPos); ~O!v?2it8q  
} ==& =3  
;TYkJH"  
&12.|  
public synchronized int write(byte[] b,int nStart,int nLen) dXZV1e1b&#  
{ u7K0m! jW  
int n = -1; 3LG)s:p$/  
try{ FKPI{l  
oSavedFile.write(b,nStart,nLen); : 7'anj  
n = nLen; 72aj4k]^  
} tq{ aa  
catch(IOException e) Gmc0yRN  
{ 278 6tZF,  
e.printStackTrace (); |#k1a:  
} N7XRk= J  
rxO|k0x^C  
9i n&\  
return n; h-V5&em"_  
} ^XV$J-  
> #SQDVFf  
l78zS'  
} |VIBSty2d  
#8cY,%<S]  
ds`a6>746  
/* 5E$)Ip  
**SiteInfoBean.java zUeS7\(l  
*/ ACs?m\$Q  
package NetFox; 2s~ X  
C]82Mt  
!9B)/Xi  
public class SiteInfoBean { OPar"z^EV  
BDpeAF8z  
B+ +:7!  
private String sSiteURL; //Site's URL F]x o*  
private String sFilePath; //Saved File's Path ,JX/` 7y  
private String sFileName; //Saved File's Name u9J;OsnHK  
private int nSplitter; //Count of Splited Downloading File 9 u{#S}c`  
w[t!?(![>  
Drz#D1-2  
public SiteInfoBean() jT%k{"+>+?  
{//nSplitter的缺省值为5 1s .Ose  
//default value of nSplitter is 5 ^8-CUH\  
this("","","",5); b k 30d  
} p\1-.  
6s@'z<Ct  
!>TH#sU$  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1t6VS 3  
{ 5#~u U  
sSiteURL= sURL; Mz_*`lRN  
sFilePath = sPath; 6p])2]N>p  
sFileName = sName; \^i/:  
this.nSplitter = nSpiltter; #}3$n/  
'7 SFa]tH  
pbt/i+!  
} lOYzo  
jw]~g+x#$  
A70x+mjy^T  
public String getSSiteURL() *H8(G%a!^  
{ 8SR~{  
return sSiteURL; u6j\@U6I  
} 8K=sx @l  
}j;*7x8(  
.IXkdy  
public void setSSiteURL(String value) eTw sh]  
{ BxVo>r  
sSiteURL = value; &z8I@^<  
} PRa #; Wb  
&==X.2XW  
nO.RB#I$F  
public String getSFilePath() gTa6%GM>  
{ vau0Jn%=ck  
return sFilePath; b\& |030+  
} dz3chy,3  
pCb3^# &o  
/i.3v45t"  
public void setSFilePath(String value) '[V}]Z>-  
{ oP vk ^H  
sFilePath = value; b+7!$  
} :!Ea.v  
<_(UAv  
K)=<hL  
public String getSFileName() jg%HaA<zO  
{ tj<a , l  
return sFileName; |:Q`9;  
} jG~zpZh  
D_VAtz  
N{rC#A3  
public void setSFileName(String value) @'XxMO[Z!<  
{ ` 9iB`<  
sFileName = value; cVk&Yp;[*  
} , z8<[Q-#  
8y:c3jzP_  
vOMmsU F  
public int getNSplitter() A|Z'\D0  
{ <B"M} Y>_P  
return nSplitter; &"G4yM  
} ~m@v ~=  
%uA\Le  
wX7|a/|@  
public void setNSplitter(int nCount) SI-G7e)3;>  
{ PH$fDbC8  
nSplitter = nCount; 1"7Rs}l7  
} * }\}@0%  
} h0;PtQb1  
b3$aPwv  
#I]5)XT  
/* ,AX7~;hpq  
**Utility.java 8}5dyn{cvE  
*/ 0qND2_  
package NetFox; z^xrB$8 u  
mI;#Zq_j  
fYv= yP~  
public class Utility { KB3zQJY  
|gl~wG1@  
Nhq& Sn2  
public Utility() ~i3/Ec0\  
{ dM|&Y6  
e<Pbsj  
9t`   
} 1K<4Kz~  
=Tdh]0  
//线程睡眠 c(:qid  
public static void sleep(int nSecond) !sbKJ+V7  
{ o'9K8q\1  
try{ 4s{_(gy  
Thread.sleep(nSecond); 7hQf T76h  
} qT U(]O1  
catch(Exception e) aahAUhF  
{ &PfCY{_  
e.printStackTrace (); BPFd'- O)  
} g\Gx oR  
} z% ln}  
BC/oh+FW3  
//日志 IYJS>G%*  
public static void log(String sMsg) rkp 1tv  
{ %&D,|Yl6  
System.err.println(sMsg); ,(%?j]_P2  
}  p^=>N9  
8|\0\Wd;vu  
32DSZ0  
public static void log(int sMsg) }8+rrzMUB  
{ vXdz?  
System.err.println(sMsg); ^>?E1J3u  
} OK=lp4X  
} D/T& 0  
=N _7DT  
}7`HJ>+m)H  
/* zvvF 9  
**TestMethod.java +3@d]JfMh  
*/ (WW*yv.J  
package NetFox; D)yCuw{M:  
VxlK:*t`  
5kX#qT=  
public class TestMethod { |*~=w J_  
M"q]jeaM  
4v@urW s  
public TestMethod() xB&kxW.;  
{ ///xx/weblogic60b2_win.exe ^H0`UKE  
try{ lq4vX^S  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); DXbzl +R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); / 7EeM{,~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 5<%]6cx}  
fileFetch.start(); F vJJpPS  
} XM0;cF  
catch(Exception e){e.printStackTrace ();} Je|D]w  
q&eUw<(F  
Hk65c0  
} ~:65e 8K  
o6@Hj+,,  
c=S-g 9J  
public static void main(String[] args) Ol;}+?[Q  
{ D$sG1*@s-  
new TestMethod(); b4_"dg~gK  
} Q?Au.q],  
} }]-SAM  
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