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http断点续传简单实现(java)

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/* (+Uo;)~!YC  
**SiteFileFetch.java 3^`bf=R  
*/ w=f8UtY9@A  
package NetFox; ^Xb!dnT.*a  
import java.io.*; JP@UvDE|  
import java.net.*; p=r{ODw#3  
5-&P4  
| _S9U|  
public class SiteFileFetch extends Thread { b,K1EEJ  
RF6|zCWuI  
Dxu )by  
SiteInfoBean siteInfoBean = null; //文件信息Bean -> <_J4  
long[] nStartPos; //开始位置 Dd{{ d?;B  
long[] nEndPos; //结束位置 &7<~Q\XZbI  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7tr.&A^c  
long nFileLength; //文件长度 IjrTM{f  
boolean bFirst = true; //是否第一次取文件 w{UU(  
boolean bStop = false; //停止标志 (m,O!935f  
File tmpFile; //文件下载的临时信息 A"P1 B]  
DataOutputStream output; //输出到文件的输出流 q?t>!1c  
5aWKyXBIx  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) z&- `<uV~  
public SiteFileFetch(SiteInfoBean bean) throws IOException h?CNChRJs  
{ NuXU2w~  
siteInfoBean = bean; F,EHZ,<V  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 1-JWqV(#?  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); }Rf } iG  
if(tmpFile.exists ()) '7=*n_l  
{ $23R%8j   
bFirst = false; Y< M}'t  
read_nPos(); %EVg.k$  
} =+"XV8Fi,  
else ](0A/,#q6  
{ S@*@*>s^  
nStartPos = new long[bean.getNSplitter()]; g6*}& .&  
nEndPos = new long[bean.getNSplitter()]; hpw;w}m  
} Gge"`AT  
E]7G4  
/_56H?w\  
R'80{  
} JUXK}0d%eN  
o= 8yp2vG  
4<O[d  
public void run() 3g6R<Ez  
{ %_3{Db`R>  
//获得文件长度 Lh. L~M1X  
//分割文件 "iKK &%W  
//实例FileSplitterFetch CP?\'a"Kt  
//启动FileSplitterFetch线程 m.4y=69 &  
//等待子线程返回   () SG  
try{ v=L^jw  
if(bFirst) 7*4F-5G/  
{ >%W"u` Q  
nFileLength = getFileSize(); I/@Xr  
if(nFileLength == -1) f{b"=hQ  
{ O=+C Kx@  
System.err.println("File Length is not known!"); *]H ./a:1  
} _R8-Hj E  
else if(nFileLength == -2) qI'a|p4fn?  
{ '<@PgO~  
System.err.println("File is not access!"); w!xSYh')  
} QR,i b  
else T*H4kM  
{ #G\)ZheG  
for(int i=0;i<nStartPos.length;i++) u{_T,k<!  
{ Y- w5S|!  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 2Nj0 Hqjq  
} G N{.R7  
for(int i=0;i<nEndPos.length-1;i++) *.K}`89T  
{ ~E`l4'g?  
nEndPos = nStartPos[i+1]; UkGUxQ,GU  
} _]Hn:O"o  
nEndPos[nEndPos.length-1] = nFileLength; 3 Zbvf^  
} ]IoS-)$Z/  
} .lE"N1  
sB"]R%`_  
Y${ $7+@  
//启动子线程 *F9uv)[kz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [` i;gx[^  
for(int i=0;i<nStartPos.length;i++) [}VEDx  
{ )@sz\yI%U  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -MU^%t;-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), `rM-b'D  
nStartPos,nEndPos,i); EGa}ml/G  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); SWmdU]  
fileSplitterFetch.start(); czT$mKj3  
} Aimgfxag  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ukPV nk  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); zz$*upxK  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4f/8APA  
nEndPos = " + nFileLength); \dCdyl6V  
// fileSplitterFetch[nPos.length-1].start(); $QY(7Z"  
g,q&A$Wi  
a(<nk5  
//等待子线程结束 OgzPX^q/=  
//int count = 0; DG& kY+  
//是否结束while循环 MqNp*n2  
boolean breakWhile = false; i .'f<z$<  
XBDlQe|>  
0ogTQ`2Z:  
while(!bStop) 9x:c"S*  
{ <4VUzgX2  
write_nPos(); 3 =S.-  
Utility.sleep(500); f:=?"MX7  
breakWhile = true; $A-b-`X  
mH8"k+k  
=?/J.[)<*  
for(int i=0;i<nStartPos.length;i++) \?}ZXKuJj  
{ 0{jRXa-(  
if(!fileSplitterFetch.bDownOver) !e%#Zb MIo  
{ kdv>QZ  
breakWhile = false; 2R)Y}*VX  
break; le1'r>E$  
} s^E%Uk m  
} ANWa%%\T  
if(breakWhile) Z3Vi il:  
break; z:acrQwJ?1  
)! OEa]  
6 .*=1P*?  
//count++; ZOU$do>O  
//if(count>4) g~`UC  
// siteStop(); PvO>}(=  
} K.1#cf ^'  
x2 tx{Z  
bhFzu[B  
System.err.println("文件下载结束!"); ~s !+9\Fi  
} Ldig/:  
catch(Exception e){e.printStackTrace ();} *VD-c  
} 8_:jPd! 3  
+nZx{d,wt  
!,I}2,1%k  
//获得文件长度 *O+N4tq  
public long getFileSize() B` n!IgF8  
{ yA6"8fr  
int nFileLength = -1; K 0b(D8!  
try{ 2N>:GwN  
URL url = new URL(siteInfoBean.getSSiteURL()); S=o Ab&  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); j'v2m6/  
httpConnection.setRequestProperty("User-Agent","NetFox"); xeZ,}YP)  
wG -X833\(  
zg"<N  
int responseCode=httpConnection.getResponseCode(); 2pZ|+!xc+  
if(responseCode>=400) ^[5yff 4  
{ ]"F0"UH,  
processErrorCode(responseCode); v k<By R  
return -2; //-2 represent access is error ;ML21OjgN  
} O.!|;)HQ  
2#p6.4h=  
rq+E"Uj?  
String sHeader; RW%e%  
tEZ@v(D  
^e)KEkh  
for(int i=1;;i++) R ]HHbD&;  
{ & [4Gv61  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _g 3hXsA  
//Utility.log(in.readLine()); Un7jzAvQ  
sHeader=httpConnection.getHeaderFieldKey(i); bluhiiATd  
if(sHeader!=null) }Vk#w%EJ  
{ f%d7?<rw  
if(sHeader.equals("Content-Length")) U%"v7G-  
{ sJMT _yt;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); h=?#D0  
break; tP7l ;EX4  
} ]B\H  
} 7H9&\ur9+  
else "1WwSh}Z  
break; S9U`-\L0  
} MejM(o_kk  
} _6xC4@~h*  
catch(IOException e){e.printStackTrace ();} jDOB (fE  
catch(Exception e){e.printStackTrace ();} %Q]m6ciAM  
m)g:@^$  
xyBWV]Y  
Utility.log(nFileLength); R$_#7>3  
6-j><'  
evz{@;.R  
return nFileLength; 0LN"azhz  
} eG=Hyc  
E2+O-;VN  
gT?:zd=;  
//保存下载信息(文件指针位置) FK{Vnj0  
private void write_nPos() R~PD[.\u  
{ (TgLCT[@T  
try{ tg.[.v Ks  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Fzt{^%\`  
output.writeInt(nStartPos.length); lN -vFna  
for(int i=0;i<nStartPos.length;i++) <$qe2Ft Uq  
{ ^ yyL4{/  
// output.writeLong(nPos); vYcea  
output.writeLong(fileSplitterFetch.nStartPos); NirG99kyo  
output.writeLong(fileSplitterFetch.nEndPos); |W:xbtPNy  
} JPR o<jt=  
output.close(); &,JrhMr\  
} W0R<^5_  
catch(IOException e){e.printStackTrace ();} 8t25wPlx  
catch(Exception e){e.printStackTrace ();} )E;B'^RVR  
} U\s.fIr  
Mj2`p#5wKh  
lhZXq!2p  
//读取保存的下载信息(文件指针位置) Eg$ I  
private void read_nPos() 7A<X!a  
{ x2%xrlv<J/  
try{ qkPvE;"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); o'+p,_y9Y@  
int nCount = input.readInt(); S ( e]@  
nStartPos = new long[nCount]; DI"KH)XD  
nEndPos = new long[nCount];  vtk0 j  
for(int i=0;i<nStartPos.length;i++) .hPk}B/KV  
{ =ss(~[  
nStartPos = input.readLong(); Bi:%}8STH  
nEndPos = input.readLong(); ] -iMo4H  
} lkl+o&D9  
input.close(); THEpW{.E  
} 8A'oK8Q  
catch(IOException e){e.printStackTrace ();} "tdF#>x  
catch(Exception e){e.printStackTrace ();} .FYxVF.  
} w#0/&\ b=  
}$ C;ccWL  
YS],o'T  
private void processErrorCode(int nErrorCode) C&wp*  
{ }w&W\g+E$  
System.err.println("Error Code : " + nErrorCode); w=JO$7  
} {8p<iY- %  
@$mh0K>  
^__';! e  
//停止文件下载 .6C9N{?Tqf  
public void siteStop() %'+}-w  
{ ?gYQE&M !  
bStop = true; 'vCl@x$  
for(int i=0;i<nStartPos.length;i++) [/E|n[Bx  
fileSplitterFetch.splitterStop(); [L(qrAQ2|z  
wB'GV1|jL  
^jh c(ZW"  
} GW{e"b/x  
} 9 n0 ?0mk  
//负责部分文件的抓取 =2XAQiUR\  
**FileSplitterFetch.java -,:^dxE'  
*/ ZQ1,6<^9i[  
package NetFox; D`c&Q4$:  
o{]2W `0r  
aoqG*qh}b  
import java.io.*; =Vie0TV&h  
import java.net.*; \0 j-p   
fbg:rH\_  
Dm{9;Abs%  
public class FileSplitterFetch extends Thread { p ; ]Qxh  
| -l9Z  
p`qy57  
String sURL; //File URL @V}!elV  
long nStartPos; //File Snippet Start Position +,c]FAx4  
long nEndPos; //File Snippet End Position MZd?cS  
int nThreadID; //Thread's ID 2^w8J w9  
boolean bDownOver = false; //Downing is over F% < ZEVm  
boolean bStop = false; //Stop identical +khVi}  
FileAccessI fileAccessI = null; //File Access interface .D3k(zZ  
V*6o|#  
{Qba`lOkq  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException z&wJ"[nOC  
{ p!/!ZIo  
this.sURL = sURL; @b&_xT  
this.nStartPos = nStart; um,G^R   
this.nEndPos = nEnd; ]621Z1  
nThreadID = id; 4$oDq  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 dD351!-  
} b9R0"w!ml  
PRal>s&f  
A<}nXHs-  
public void run() 7TW&=(  
{ e+~@"^|  
while(nStartPos < nEndPos && !bStop) =|LB,REN  
{ imc1rY!~'  
:8t;_f  
LK|1[y^h  
try{ W:VX^8</  
URL url = new URL(sURL); 7TtDI=f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B4/\=MXb  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7u`:e,'  
String sProperty = "bytes="+nStartPos+"-"; A$3ll|%j  
httpConnection.setRequestProperty("RANGE",sProperty); W"!{f  
Utility.log(sProperty); Egt !N  
#g#[|c.  
.QW@rV:T  
InputStream input = httpConnection.getInputStream(); }D]y -BbA.  
//logResponseHead(httpConnection); * ,L e--t  
" M3S  
s5\<D7  
byte[] b = new byte[1024]; sK@]|9ciQ  
int nRead; r XT6u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) K-b`KcX  
{ fl8eNi E|  
nStartPos += fileAccessI.write(b,0,nRead); .4J7 ^l  
//if(nThreadID == 1) 9fy[%M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b5)1\ANq  
} NT=)</v  
)8E[xBaO  
eGW h]%  
Utility.log("Thread " + nThreadID + " is over!"); 3Yf~5csY  
bDownOver = true; OUhlQq\  
//nPos = fileAccessI.write (b,0,nRead); .I Io   
} e}NB ,o  
catch(Exception e){e.printStackTrace ();} \E1CQP-  
} =F% <W7  
} 1* ?XI  
2)Q%lEm`SP  
;TKsAU  
//打印回应的头信息 R8>17w.  
public void logResponseHead(HttpURLConnection con) X`C ozyYuD  
{ ;w;+<Rd  
for(int i=1;;i++) u p zBd]  
{ V]Kk =  
String header=con.getHeaderFieldKey(i); 0DaKd<Scv  
if(header!=null) I6i qC"BK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); jZk dTiI  
Utility.log(header+" : "+con.getHeaderField(header)); !{F\ \D/  
else rRX F@  
break; -amNz.`[PR  
} 8dh ?JqX  
} &,QBJx<#  
 _ 'K6S  
Y,m=&U  
public void splitterStop() m~tv{#Y  
{ A |P wm`  
bStop = true; %_(^BZd  
} B A i ^t  
J u"/#@  
[U,hb1Wi3  
} s( :N>K5*  
PKZMuEEy,  
-n:;/ere7-  
/* g*WY kv  
**FileAccess.java *|,ye5"  
*//文件访问(定位,写) lQL /I[}  
package NetFox; B$G9#G6pZ  
import java.io.*; h^f?rWD:nz  
o,qUf  
LYuMR,7E  
public class FileAccessI implements Serializable{ _6`H `zept  
qgxGq(6K  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :n OCs  
RandomAccessFile oSavedFile; g6h=Q3@  
long nPos; Yq:+.UU  
l]L"Ex{  
$VeQvm*  
public FileAccessI() throws IOException L;U?s2&Y  
{ (Bss%\  
this("",0); +;a\ gF^  
} c^~R %Bx  
lT8^BT  
l M a||  
public FileAccessI(String sName,long nPos) throws IOException |~+bbN|b  
{ `pXPF}T  
oSavedFile = new RandomAccessFile(sName,"rw"); /~+j[o B  
this.nPos = nPos; op,mP0b  
oSavedFile.seek(nPos); #;\tgUQ  
} in>?kbaG+  
Np?/r}  
#U6~U6@  
public synchronized int write(byte[] b,int nStart,int nLen) ,o\~d ?4  
{ B7n1'?  
int n = -1; Lw6}b B`}  
try{ HHZrovA#  
oSavedFile.write(b,nStart,nLen); Ku8qn \2"  
n = nLen; }q)dXFL=I#  
} r#c+{yY  
catch(IOException e) `L"l{^cH  
{ 85{@&T  
e.printStackTrace (); V7?Pv Q  
} Vah.tOU  
Zzv,p  
N#^o,/  
return n; 1ifPc5j}  
} ?dvcmXR  
S^)xioKsJ  
\; zix(N[5  
} %`j2?rn  
N lB%Qu  
b|U3\Fmc  
/* b(_PV#@$  
**SiteInfoBean.java 5xc-MkIRL  
*/ - P'c0I9z  
package NetFox; eSSv8 [u  
0*:4@go0}i  
XtIY8wsP  
public class SiteInfoBean { ^oZD44$  
KCfcEz  
E>rWm_G  
private String sSiteURL; //Site's URL A w)P%r  
private String sFilePath; //Saved File's Path "0{t~?ol  
private String sFileName; //Saved File's Name T0BM:ofx  
private int nSplitter; //Count of Splited Downloading File W4=<hB  
7;NvR4P%  
(L"G,l  
public SiteInfoBean() k5)e7Lb(  
{//nSplitter的缺省值为5 xcN >L  
//default value of nSplitter is 5 ] dHV^!  
this("","","",5); WC 5v#*Jd  
} y_Nn%(j  
+WSM<S2 U  
#}zL?s^G  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {pEbi)CF,}  
{ U=ie| 3  
sSiteURL= sURL; v,mn=Q&9  
sFilePath = sPath; ?)XPY<  
sFileName = sName; ^BQ*l5K  
this.nSplitter = nSpiltter; @Ke3kLQ_\X  
xkkW?[&  
'q{|p+  
} m>-(c=3  
:_+Fe,h>|  
O\zGN/!  
public String getSSiteURL() }t.VH:02y  
{ D(Yq<%Q  
return sSiteURL; 3,{tGNl|  
} /yL:_6c-  
\:91BQP c  
] 73BJ  
public void setSSiteURL(String value) VTxLBFK;  
{ hG.~[#[&6  
sSiteURL = value; _z \PVTT  
} ahm@ +/2  
2~SjRIpUw  
j!QP>AM|`  
public String getSFilePath() vq*)2.  
{ ]0)=0pc]E  
return sFilePath; UZqk2D  
} V7i1BR8G  
|.[4$C  
""^.fh  
public void setSFilePath(String value) a |+q:g0M  
{ kDr0D$iE  
sFilePath = value; b7? 2Pu  
} [lX3":)  
-( +/u .  
7= x]p  
public String getSFileName() z'ZGN{L  
{ zq&,KZ  
return sFileName; >L>t$1hXM  
}  e{33%5  
QH_I<Y:n  
5\$8"/H  
public void setSFileName(String value) p;m2RHYF  
{ }w8:`g'T0/  
sFileName = value; 1A b=1g{  
} kKR Z79"7s  
_<1uO=km6  
o]|a5. O  
public int getNSplitter() ^gD%#3>X  
{ 5KFd/9  
return nSplitter; =e$6o2!'}  
} eb>YvC  
v(2|n}qY  
|,Xrt8O/[  
public void setNSplitter(int nCount) ghd*EXrF H  
{ 1f^4J~{  
nSplitter = nCount; C) "|sG  
} *R^ulp[W  
} h_Cac@F0  
-(fvb  
'@<aS?@!t  
/* pu +"bq  
**Utility.java aPMqJ#fIr  
*/ aD:vNX  
package NetFox; KW.QVBuVO#  
(C EXPf  
4_w+NI,;  
public class Utility { uZ(j"y  
vQpR0IEf]e  
:D'#CoBA  
public Utility() + B#3!  
{ @fWmz,Ngl  
UR&Uwa&.  
c~+;P(>  
} U,4:yc,)s  
v8xNtUxN  
//线程睡眠 6T5nr  
public static void sleep(int nSecond) Cq,ox'kGl  
{ YdK]%%  
try{ PDnwaK   
Thread.sleep(nSecond); zi*2>5g  
} `2@t) :  
catch(Exception e) OyG$ ]C  
{ P]@m0f  
e.printStackTrace (); [fU2$(mT+  
} )MKzAAt~  
} =-c"~4  
t$z FsFTQ  
//日志 D$RQD{*  
public static void log(String sMsg) 9 1r"-%(r  
{ idf~"a  
System.err.println(sMsg); #Pz},!7  
} iraO/KhD*3  
bS+by'Ea1W  
Dm1;mRS+  
public static void log(int sMsg) y+XB  
{ . ` OdnLGy  
System.err.println(sMsg); I =t{ u;  
} Zq--m/  
} Ny>tJ~I  
4 }l,F  
r2T-=XWB  
/* / W}Za&]  
**TestMethod.java 0.+"K}  
*/ P{eL;^I  
package NetFox; !S[8w9q  
tIgKnKr^)  
aD~3C/?aW  
public class TestMethod { m>gok0{pm  
c8sY#I  
:o}J u}t  
public TestMethod() tVZj tGz=  
{ ///xx/weblogic60b2_win.exe xFpMn}CD  
try{ ; 2vHdN  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^3Ni  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); K YFumR  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i51~/ R  
fileFetch.start(); &P%3'c}G  
} vv  _I o  
catch(Exception e){e.printStackTrace ();} 1FS Jqad  
\k1psqw^O  
J(0.eD91v  
} D 5]sf>~  
Nw}y_Qf{  
!aD/I%X  
public static void main(String[] args) Zi=Nr3b  
{ ?L$ Dk5-W  
new TestMethod(); f~u]fpkz  
} 4}{HRs?  
} SLL%XF~/Sb  
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