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http断点续传简单实现(java)

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/* 7)BK&kpVr  
**SiteFileFetch.java 7!~)a  
*/ 9 u>X,2gUR  
package NetFox; jSw>z`'#H  
import java.io.*; !T.yv5ge'  
import java.net.*; zANsv9R~  
tcD5"ALJ  
V]/ $ dJ  
public class SiteFileFetch extends Thread { i<!1s%i}  
T/tCX[}  
R#Z m[S  
SiteInfoBean siteInfoBean = null; //文件信息Bean 6%&DJBU!  
long[] nStartPos; //开始位置 awSi0*d~  
long[] nEndPos; //结束位置 J!H)[~2/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _xM3c&VeG  
long nFileLength; //文件长度 7b(r'b@N  
boolean bFirst = true; //是否第一次取文件 PQ" v  
boolean bStop = false; //停止标志 @eP(j@(^  
File tmpFile; //文件下载的临时信息 8aVj@x$'  
DataOutputStream output; //输出到文件的输出流 Z& bIjp  
fz rH}^  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) :MGIp%3  
public SiteFileFetch(SiteInfoBean bean) throws IOException Bpv"qU7  
{ gH0Rd WX  
siteInfoBean = bean; EE*FvI`  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X3l6b+p  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); rfOrh^  
if(tmpFile.exists ()) yJ!,>OQ%'  
{ <o@__l.  
bFirst = false; 8O0]hz  
read_nPos(); NZ- 57Ji  
} W7w*VD|  
else _ 3{8Zg  
{ r|3<UR%  
nStartPos = new long[bean.getNSplitter()]; 3u'@anre  
nEndPos = new long[bean.getNSplitter()]; F 7X ] h  
} 9Yji34eDZ  
k"+/DK,:  
*enT2Q  
CL5t6D9Qi  
} 5oR)  
C <H$}f  
O*9d[jw[  
public void run() IW=%2n(<1  
{ &7KX`%K"D  
//获得文件长度 ~uuM0POo  
//分割文件 ZSn6JV'g  
//实例FileSplitterFetch A6#v6iT  
//启动FileSplitterFetch线程 DS7Pioa86  
//等待子线程返回 J74kK#uF=  
try{ R".*dC,0'B  
if(bFirst) [k=LX+w@  
{ ,9W!cD+0  
nFileLength = getFileSize(); .19_EQ>+  
if(nFileLength == -1) rrl{3 ?  
{ WB"90!  
System.err.println("File Length is not known!"); ;MW=F9U*  
} :Y4G^i  
else if(nFileLength == -2) GX N:=  
{ $~r=I[5'(  
System.err.println("File is not access!"); XW*d\vDun  
} 1(/rg  
else }LX.gm  
{ ) Hqn  
for(int i=0;i<nStartPos.length;i++) P]4@|u;=6[  
{ YGZa##i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); !uhh_3RH  
} &izk$~  
for(int i=0;i<nEndPos.length-1;i++) p9eTrFDy?  
{ nu6v@<<F>  
nEndPos = nStartPos[i+1]; [-1Yyy1}  
} ]F4|@+\9  
nEndPos[nEndPos.length-1] = nFileLength; Jg@eGs\*  
} ORt)sn&~d  
} U-#vssJhk  
8CRwHDB  
F ZfhiIf  
//启动子线程 -9(nsaV  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `12Y2W 9  
for(int i=0;i<nStartPos.length;i++) D`PA@t  
{ K# h7{RE  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RYM[{]4b5F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /[|A(,N}{  
nStartPos,nEndPos,i); ?aU-Y_pMe  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E>kgEfzxP  
fileSplitterFetch.start(); 2~@Cj@P]  
} df9$k0Fx  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xUIH,Fp-9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $3(E0\#O  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $lF\FC  
nEndPos = " + nFileLength); /+f3jy:d  
// fileSplitterFetch[nPos.length-1].start(); .;37 e  
jk5C2dy  
\5F {MBx !  
//等待子线程结束 U.J/ "}5`T  
//int count = 0; ,sn 9&E  
//是否结束while循环 ZV`o: Gd  
boolean breakWhile = false; I_ na^s h*  
q`@8  
% &i Wc_"  
while(!bStop) 0V'XE1h  
{ !3Q^oR  
write_nPos(); 5I0j>{U&  
Utility.sleep(500); 3NrWt2?  
breakWhile = true; i",oPz7  
( Uk\O`)m  
Uy$?B"Z  
for(int i=0;i<nStartPos.length;i++) 8LlWXeD9  
{ um$L;-2:  
if(!fileSplitterFetch.bDownOver) Xl/2-'4  
{ _8OSDW*D5t  
breakWhile = false; trL8oZ6  
break; Pol c.  
} k; vhQ=  
} @BqSu|'Du,  
if(breakWhile) A@n//AZM  
break; n<MreKixE  
:SVWi}:Co1  
sT>l ?L  
//count++; %>,Kd6bdg  
//if(count>4) Ai5D[ykX  
// siteStop(); k E-+#p  
} RGLi#:0_.x  
,kE"M1W  
TuzH'F  
System.err.println("文件下载结束!"); ;V4f6[<]'z  
} ]ru UX  
catch(Exception e){e.printStackTrace ();} * v u  
} 2$?j'i!  
V e4@^Jy;  
\yY2 mr  
//获得文件长度 O+o_{t\R  
public long getFileSize() ~Q5 i0s%  
{ \>  
int nFileLength = -1; /@]@Tz@'  
try{ P6;Cohfh  
URL url = new URL(siteInfoBean.getSSiteURL()); 1lf]}V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); {_]<mwd  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y!AQ7F  
Yx<wYzD  
.0]Odf:@  
int responseCode=httpConnection.getResponseCode(); 1)ZdkTF@H  
if(responseCode>=400) r<-@.$lf  
{ :tBZu%N/N  
processErrorCode(responseCode); d ]Mjr2h  
return -2; //-2 represent access is error F6-U{+KU$!  
} Nrk/_0^  
Eb9{  
K?acRi  
String sHeader; S$ 91L  
Z;J{&OJ3qM  
S$i3/t  
for(int i=1;;i++) ,98`tB0  
{ x-@6U  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ZVz`-h B  
//Utility.log(in.readLine()); f}+8m .g2  
sHeader=httpConnection.getHeaderFieldKey(i);  ~b LhI  
if(sHeader!=null) `r.  
{ `rI[   
if(sHeader.equals("Content-Length")) XnV$}T:?X  
{ 3ypf_]<  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); firiYL"=44  
break; VseeU;q  
} s@5r}6?M  
} IP l]$j>N  
else u YJL^I8M'  
break; [7gwJiK  
} !7aJfs2  
} Bhw|!Y&%  
catch(IOException e){e.printStackTrace ();} '@eH)wh@m)  
catch(Exception e){e.printStackTrace ();} Y(P <9 m:  
T'e p&tNY  
C\; $RH  
Utility.log(nFileLength); ?\![W5uuXG  
GYN Lyd)  
&Ch~$Wb^  
return nFileLength; c9R|0Yn^J  
} o|7 h  
#"aL M6Cfs  
LkIbvJCV  
//保存下载信息(文件指针位置) [5QbE$  
private void write_nPos() -O?&+xIK&  
{ J1{ucFa  
try{ >X-*Hu'U#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ,{u'7p  
output.writeInt(nStartPos.length); '.d]n(/lZd  
for(int i=0;i<nStartPos.length;i++) %& b70]S(  
{ QLe<).S1B2  
// output.writeLong(nPos); 7NDjXcuq  
output.writeLong(fileSplitterFetch.nStartPos); 8S7 YVsDz"  
output.writeLong(fileSplitterFetch.nEndPos); ouR(l;  
} gPg2Ve0Qy  
output.close(); hDHIi\%  
} # dxS QmG  
catch(IOException e){e.printStackTrace ();} P0XVR_TJf  
catch(Exception e){e.printStackTrace ();} b#E!wMClS  
} +K03yphZr  
!0 -[}vvU  
'7TT4~F  
//读取保存的下载信息(文件指针位置) 9!|+GIjn  
private void read_nPos() c9)5G+   
{ lM-*{<B  
try{ )m[dfeqd +  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); "=\@ a=  
int nCount = input.readInt(); .>{I S4  
nStartPos = new long[nCount]; D!CuE7}  
nEndPos = new long[nCount]; 1rQKHC:|  
for(int i=0;i<nStartPos.length;i++) S K7b]J>  
{ 'or8CGr^p  
nStartPos = input.readLong(); !`EhVV8u-_  
nEndPos = input.readLong(); C#4/~+  
} caC( KK#<  
input.close(); DX%D8atrr  
} SHT^Etri  
catch(IOException e){e.printStackTrace ();} <P4*7:jX  
catch(Exception e){e.printStackTrace ();} f!aE/e\  
} LX_{39?<{  
;(,1pi7|  
ZP^7`q)6  
private void processErrorCode(int nErrorCode) I`8jJpGA  
{ <{UjO  
System.err.println("Error Code : " + nErrorCode);  `Aa*}1  
} za oC  
Wx-vWWx*Q  
eGh7,wngH  
//停止文件下载 -C<Ni  
public void siteStop() bem-T`>'  
{ 7JHS8C<]  
bStop = true; Kk_h&by?  
for(int i=0;i<nStartPos.length;i++) ('VHL!  
fileSplitterFetch.splitterStop(); ' 5%`[&  
A/#Xr  
sCE2 F_xjL  
} -!b@\=  
} @CU~3Md*  
//负责部分文件的抓取 y:3d`E4Xw  
**FileSplitterFetch.java %:WM]dc  
*/ '4}c1F1T_  
package NetFox; <UMT:`h1MZ  
Yab=p 9V;;  
~ GW8|tw  
import java.io.*; "~HV!(dRMC  
import java.net.*; -L%2*`-L$  
j1{\nP/  
Om=*b#k  
public class FileSplitterFetch extends Thread { ]h6mJ{k  
T11;LSD  
K0Zq )<  
String sURL; //File URL X ?lF,p  
long nStartPos; //File Snippet Start Position |ZnRr  
long nEndPos; //File Snippet End Position |U4t 8  
int nThreadID; //Thread's ID Lc:DJA  
boolean bDownOver = false; //Downing is over oK3aW6  
boolean bStop = false; //Stop identical 78i"3Tm)w  
FileAccessI fileAccessI = null; //File Access interface R1=ir# U|D  
mv+K!T6  
f8'$Mn,  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException O#5ll2?  
{ , JUP   
this.sURL = sURL; 1KtPq,  
this.nStartPos = nStart; (ATCP#lF  
this.nEndPos = nEnd; 8 K/o/  
nThreadID = id; mC}!;`$8p  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 >7^+ag~&  
} "Nn+Zw43  
)QvuoaJQ  
+ $x;FT&  
public void run() w>W`8P_b@  
{ f YuM`O  
while(nStartPos < nEndPos && !bStop) ^sjL@.'m$N  
{ L!]~ J?)  
sUP !'Av  
@~l?hf  
try{ >.-$?2  
URL url = new URL(sURL); X;?Z_3I:5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); * (4TasQu  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y/1,%8n  
String sProperty = "bytes="+nStartPos+"-"; o-D,K dY  
httpConnection.setRequestProperty("RANGE",sProperty); A|esVUo<3^  
Utility.log(sProperty); 9IRvbE~2  
_\tGmME37  
#1C~i}J1  
InputStream input = httpConnection.getInputStream(); 9C{\=?e;  
//logResponseHead(httpConnection); n*oa J<o%  
A' \jaB  
<XHS@|  
byte[] b = new byte[1024]; ]U,K]y[Bj  
int nRead; U|%y `PZ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) h1 D#,  
{ (BA2   
nStartPos += fileAccessI.write(b,0,nRead); 426)H_wx  
//if(nThreadID == 1) iC{~~W6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z{w{bf1&A  
} "k${5wk#Fl  
yeCR{{B/'  
<9s=K\-  
Utility.log("Thread " + nThreadID + " is over!"); f 2#9E+IQ  
bDownOver = true; cc%O35o  
//nPos = fileAccessI.write (b,0,nRead); ($oO, c'z  
} 4P>tGO&*x  
catch(Exception e){e.printStackTrace ();} 4#qjRmt  
} $pT%7jV}  
} <}E^r_NvD  
Bn"r;pqWiT  
[wM<J$=2  
//打印回应的头信息 m7XJe[O  
public void logResponseHead(HttpURLConnection con) Qjj:r~l  
{ Qn7l-:`?  
for(int i=1;;i++) |m%M$^sZ}  
{ &E{5k{Y  
String header=con.getHeaderFieldKey(i); 6rnehv!p  
if(header!=null) y%H;o?<WX  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); PSdH9ea  
Utility.log(header+" : "+con.getHeaderField(header)); r]{fjw(~  
else p.2>- L  
break; :`Kr|3bQ  
} @HfWAFT  
} RT45@   
{tE/Jv $  
%(-YOTDr  
public void splitterStop() -%=StWdb   
{ i;0`d0^  
bStop = true; ,<lxq<1I  
} OU(z};Is6Z  
?CS jn  
?;,Al`/^  
} '^l/e: (H3  
]kmOX  
gkpNT)  
/* bH41#B  
**FileAccess.java oPNYCE  
*//文件访问(定位,写) y0qE::/H$  
package NetFox; vtFA#})~  
import java.io.*; oT5xe[{yj  
K.2M=Q  
g[;iVX^1&  
public class FileAccessI implements Serializable{ f*~ 4Kv  
%uGA+ \b  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @"s\eL,r  
RandomAccessFile oSavedFile; 5Ag>,>kJ6  
long nPos; Uc0AsUu}?  
Q:~w;I  
@2_s;!K  
public FileAccessI() throws IOException +k"dN^K]D  
{ Et'C4od s  
this("",0); wN)R !6  
} kXC.rgal  
bE>3D#V<  
ABV\:u  
public FileAccessI(String sName,long nPos) throws IOException ^+[o +  
{ 2vnzB8 "k  
oSavedFile = new RandomAccessFile(sName,"rw"); FGx_ qBG4|  
this.nPos = nPos; 4Uf+t?U9  
oSavedFile.seek(nPos); e #^|NQ<'A  
} Z"? AaD[  
fC3IxlG  
s/[i>`g/9  
public synchronized int write(byte[] b,int nStart,int nLen) ud:?~?j&w  
{ U30)r+&  
int n = -1; ^TWN_(-@  
try{ ~rCnST  
oSavedFile.write(b,nStart,nLen); n@L!{zY  
n = nLen; l7{hq}@;cC  
} 8"LaP3U  
catch(IOException e) )O- x1U  
{ %FFw!eVi  
e.printStackTrace (); FA^x|C=$  
} ~+7yi4(i  
-e(2?Xq9  
/&j4IlT  
return n; Xs?7Whc6  
} zF i+6I$  
TiBE9  
;oFaDTX]  
} X}z KV  
<(p1 j0_Q  
l*Y~h3  
/* 0HD1Ob^@  
**SiteInfoBean.java 5,AQ~_,'\  
*/ ,f?#i%EF&  
package NetFox; 6 qKIz{;  
UuT[UB=x5  
)N=b<%WD   
public class SiteInfoBean { /1li^</|p`  
G0s:Dum  
=cC]8Pz?  
private String sSiteURL; //Site's URL cn\& ;55v  
private String sFilePath; //Saved File's Path f!$J_dz  
private String sFileName; //Saved File's Name >qF KXzI  
private int nSplitter; //Count of Splited Downloading File sf*SxdoZU  
[ !R%yD;  
wCt+{Y3T  
public SiteInfoBean() 4\OELU  
{//nSplitter的缺省值为5 Ok`U*j  
//default value of nSplitter is 5 )vU{JY;  
this("","","",5); Ic=V:  
} H+5]3>O-$  
^LU[{HZV  
k13/yiv  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +~fu-%,k  
{ M.8!BB7\8e  
sSiteURL= sURL; w|nVK9.  
sFilePath = sPath; EhFhL4Xdn  
sFileName = sName; l.)N  
this.nSplitter = nSpiltter; Ba+OoS  
BWPYHWW}E  
NUnP'X=J,  
} a+~o: 5  
ABHZ)OM  
Lv^j l  
public String getSSiteURL() x b0+4w|  
{ }\0"gM  
return sSiteURL; b/K&8C,c  
} ai`:HhE  
=!CuCV7$1O  
yX~[yH+Pn  
public void setSSiteURL(String value) m~U{ V9;*  
{ F>b6fUtR  
sSiteURL = value; Uqpvj90sw  
} 0&nF Vsz  
654%X(:q  
R$@.{d&:w  
public String getSFilePath() |Gf{}  
{ {f&ga  
return sFilePath; _uu:)%  
} wwAT@=X*}  
iE Oyc59  
B7PmG f)b  
public void setSFilePath(String value) .-|O"H$  
{ 7}x-({bqy  
sFilePath = value; )ED[cYGx  
} PjP%,-@1  
=0)^![y]v  
xqtjtH9X  
public String getSFileName()  XGoy#h  
{ "/'= gE  
return sFileName; L,D>E  
} /r%+hS  
$F-XXBp  
PW`Tuj  
public void setSFileName(String value) jFXU xf  
{ Na6z,TW  
sFileName = value; CbHNb~  
} <M7* N .  
 j%}Jl  
xKr,XZu  
public int getNSplitter() `SwnKg  
{ 0&\Aw'21  
return nSplitter; heKI<[8l  
} 2$o[  
0/ Ht;(  
'oHR4O*  
public void setNSplitter(int nCount) _Nn!SE   
{ ,![=_d  
nSplitter = nCount; mCGcM^21-x  
} fEjW7 c  
} LNZ#%R~r  
V3oAZ34)  
1 ~7_!  
/* C#~MR+;  
**Utility.java oSl>%}  
*/ ZYsFd_  
package NetFox; EDo@J2A  
@(cS8%wK  
xB(:d'1|  
public class Utility { x]ti3?w  
6b/b} vl  
':V_V. :  
public Utility() S>,I&`yi  
{ Flxo%g};  
QC4T=E]` j  
i-?zwVmn  
} @;6}xO2  
y2R=%EFh6  
//线程睡眠 re!8nuBsA  
public static void sleep(int nSecond) ]CZLaID~  
{ vVYduvw  
try{ V8yX7yx  
Thread.sleep(nSecond); FZnH G;af  
} ^JtHTLHL=  
catch(Exception e) Y*k<NeDyn  
{ lAk1ncx  
e.printStackTrace (); i'wF>EBz  
} V@S/!h+  
} !7)ID7d  
#'x?) AS  
//日志 WQpJd7  
public static void log(String sMsg) :6?&FzD`  
{ 3- bcY4  
System.err.println(sMsg);  W6O.E  
} ikhX5 &e  
ku;nVV  
2Nkn C>9(\  
public static void log(int sMsg) @'*#]YU8  
{ CLfb`rF  
System.err.println(sMsg); !)3s <{k#  
} cf'}*$[S  
} -mJ&N  
?0mJBA  
0lCd,a 2:  
/* RuNH (>Eb  
**TestMethod.java p^rX.?X  
*/ ~5uNw*H  
package NetFox; 6wB>-/'Y  
0NtsFPO  
]&U|d  
public class TestMethod { Noxz kpMF  
&t/<yq}{  
9yo[T(8  
public TestMethod() %"Q!5qH&  
{ ///xx/weblogic60b2_win.exe iwJ-<v_:h  
try{ e H  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); T(UYlLe  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); wmE,k1G  
SiteFileFetch fileFetch = new SiteFileFetch(bean); R0mT/h2  
fileFetch.start(); &H1D!N  
} '1'1T5x~  
catch(Exception e){e.printStackTrace ();} 9! HMQ  
.eNwC.8i  
s66XdM  
} ~cBc&u:"  
Z 034wn\N  
]8>UII,US  
public static void main(String[] args) 'uAC oME@  
{ hav?mnVJ  
new TestMethod(); N#['fg'  
} ~_db<!a  
} P .4b+9T x  
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