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http断点续传简单实现(java)

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/* JQv ZTwSI  
**SiteFileFetch.java HCCp<2D"C  
*/ ojI"<Q~g  
package NetFox; S`PSFetC  
import java.io.*; ;5S7_p2]j  
import java.net.*; 9d|7#)a;  
:)S4MoG  
 y3$\ m  
public class SiteFileFetch extends Thread { tg4&j$  
)bJ6{&  
c8 fb)`,k  
SiteInfoBean siteInfoBean = null; //文件信息Bean *8HxJ+[,[  
long[] nStartPos; //开始位置 d:ajD  
long[] nEndPos; //结束位置 W..>Ny;'3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %=>xzP(z  
long nFileLength; //文件长度 Z%d4V<fn  
boolean bFirst = true; //是否第一次取文件 Q9 ",  
boolean bStop = false; //停止标志 VZl0)YLK  
File tmpFile; //文件下载的临时信息 U*l>8  
DataOutputStream output; //输出到文件的输出流 xL#oP0d<e  
Y'":OW#oN  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) T"lqPbK  
public SiteFileFetch(SiteInfoBean bean) throws IOException rW .0_*  
{ .=<pU k 3G  
siteInfoBean = bean; 6@36 1f[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =hb87g.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !I  P*  
if(tmpFile.exists ()) alD|-{Bf  
{ yL,B\YCf8  
bFirst = false; \M^4DdAy  
read_nPos(); 4& WzG nK  
} tG&B D\  
else +OP'/  
{ k18V4ATE]  
nStartPos = new long[bean.getNSplitter()]; 4IpFT;`q  
nEndPos = new long[bean.getNSplitter()]; TUCp mj  
} rI$10R$+H  
;\0RXirk  
@AyW9!vV;3  
q&x#S_!  
} p{GDW_  
8z v6Mx  
Qc/J"<Lx  
public void run() M#,+p8  
{ G7xjW6^T  
//获得文件长度 4H '&5  
//分割文件 b8Sl3F?-~  
//实例FileSplitterFetch ~Dh}E9E:  
//启动FileSplitterFetch线程 At:C4>HE@  
//等待子线程返回 eHIC'b.  
try{ |]^! 4[!U  
if(bFirst) x$4'a~E  
{ 9&jNdB  
nFileLength = getFileSize(); TR7TF]itb  
if(nFileLength == -1) a2n#T,kq&  
{ 2sq<"TlQXI  
System.err.println("File Length is not known!"); $RO=r90o  
} DSa92:M}  
else if(nFileLength == -2) *GnO&&m'B  
{ 3_:k12%p  
System.err.println("File is not access!"); 3"RZiOyv  
} ,]' !2?  
else yIP IA%dJ  
{ SJe;T  
for(int i=0;i<nStartPos.length;i++) 1EB`6_>y  
{ bBL"F!.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1Tkz!  
} 3iwZUqyq  
for(int i=0;i<nEndPos.length-1;i++) 4,8 =[  
{ |'#NDFI>}  
nEndPos = nStartPos[i+1]; 0}!lN{m?  
} *?\Nioii  
nEndPos[nEndPos.length-1] = nFileLength; <#Dc(VhT  
} 0cVXUTJ|W  
} K>~l6  
S6I8zk)Z4  
>^}z  
//启动子线程 ~{{:-XkVB  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; oyY,uB.|  
for(int i=0;i<nStartPos.length;i++) cgAcAcmY  
{  }P#gXG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), igCtq!.a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), %kT:"j(xW  
nStartPos,nEndPos,i); ~I74'  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +g&W423k_  
fileSplitterFetch.start(); jHzb,&  
} 6cvm\ opH  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4kEFbzwx  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); otx7J\4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e)8iPu ..  
nEndPos = " + nFileLength); bv0 %{u&  
// fileSplitterFetch[nPos.length-1].start(); I Cs1=  
vhW '2<(  
?*0kQo'  
//等待子线程结束 -fv.ByyA  
//int count = 0; J %t1T]y~  
//是否结束while循环 jrR~V* :k  
boolean breakWhile = false; ycN_<  
Q)/q h;R u  
-0{WB(P  
while(!bStop) ZVL0S{V-mh  
{ "-oC,;yq  
write_nPos(); 6fiJ' j@  
Utility.sleep(500); .[! ^ L  
breakWhile = true; |iI`p-L9  
_!ed.h.r:  
;K!Or  
for(int i=0;i<nStartPos.length;i++) Z:{Z&HQC  
{ Z^'; xn  
if(!fileSplitterFetch.bDownOver) 195(Kr<5$  
{ $qqusa}`K  
breakWhile = false; jEadVM9  
break; S/|8' x{<  
} ] Yy Sf  
} P!/8   
if(breakWhile) uQlVzN.?  
break; Fk\xq`3'c  
<|@9]>z  
_rv_-n]"o  
//count++; (46)v'?  
//if(count>4) bPEAG=l"-  
// siteStop(); ,>Q,0bVhH0  
} l)Hu.1~  
*!/9?M{p  
C*$/J\6xy  
System.err.println("文件下载结束!"); +q;^8d>  
} v3B ^d}+.  
catch(Exception e){e.printStackTrace ();} 3 V<8  
} ,3K?=e2  
B.o&%5dG  
0IZV4{  
//获得文件长度 sQkP@Y  
public long getFileSize() sYL+;(#t  
{ QB7<$Bp  
int nFileLength = -1; Z=xrj E  
try{ bF.Aj8ZQ  
URL url = new URL(siteInfoBean.getSSiteURL()); 1/ HofiIa  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \n5,!,A  
httpConnection.setRequestProperty("User-Agent","NetFox"); \Z$*8z=  
Z7Kc`9.0|  
)`)cB)s  
int responseCode=httpConnection.getResponseCode(); ZO,]h9?4  
if(responseCode>=400) bFpwq#PDW>  
{ nsPM`dz/  
processErrorCode(responseCode); eNNK;xXe#  
return -2; //-2 represent access is error @RjLDj+)S  
} V\_ &2',t  
^l9S5 {  
`7LdF,OdE  
String sHeader; nm)F tX|A  
fu`oDi  
bvoR?D\-"  
for(int i=1;;i++) B`vV[w?  
{ B\Uj  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); mVxS[Gq  
//Utility.log(in.readLine()); ~9{.!7KPc  
sHeader=httpConnection.getHeaderFieldKey(i); V\ |b#?KL  
if(sHeader!=null) (b(iL\B$D=  
{ uW]n3)7<I  
if(sHeader.equals("Content-Length")) ;3w W)gL1  
{ uwbj`lpf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;y"DEFs,u  
break; k,?k37%T]  
} ZjzQv)gZ  
} /+rHy7(\  
else UZyo:*yB  
break; ]!/1qF  
} gw H6r3=y(  
} PKP( :3|  
catch(IOException e){e.printStackTrace ();} bNXT*HOZb3  
catch(Exception e){e.printStackTrace ();} de"*<+  
P^ a$?  
%l>^q`p  
Utility.log(nFileLength); @=$;^}JS|  
oOuWgr]0  
qLR)>$  
return nFileLength; YcIk{_N3  
} rn(T Z}  
)msqt!Ev  
k @[Bx>  
//保存下载信息(文件指针位置) N(D_*% 96  
private void write_nPos() |[*b[O 1W  
{ 6`4=!ZfI  
try{ $ED<:[3N  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5[0n'uH  
output.writeInt(nStartPos.length); sp JB6n(  
for(int i=0;i<nStartPos.length;i++) P? >p+dM  
{ Ef#%4ky  
// output.writeLong(nPos); Z yIn>]{  
output.writeLong(fileSplitterFetch.nStartPos); mX %;  
output.writeLong(fileSplitterFetch.nEndPos); Mq$e5&/  
} o0AREZ+I  
output.close(); *r%=p/oQ}B  
} !dZC-U~  
catch(IOException e){e.printStackTrace ();} R#oXQaBJ  
catch(Exception e){e.printStackTrace ();} 4B) prQ3  
} !bQ5CB  
gzeG5p  
:Vv=p*~  
//读取保存的下载信息(文件指针位置) CYz]tv}g:  
private void read_nPos() ZMbv1*Vt  
{ QH+Oi&xH  
try{ {4 *ob@w*  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ur_~yX]Mo  
int nCount = input.readInt(); #\fAp RL  
nStartPos = new long[nCount]; q")}vN  
nEndPos = new long[nCount]; gg933TLu(Q  
for(int i=0;i<nStartPos.length;i++) gQ& FO~cr  
{ syMB~g  
nStartPos = input.readLong(); zg[ksny  
nEndPos = input.readLong(); OD{Rh(Id  
} [gU z9iU  
input.close(); tlc&Wx  
} {eS!cZJ  
catch(IOException e){e.printStackTrace ();} L~~;i'J  
catch(Exception e){e.printStackTrace ();} wF}/7b54  
} kZfO`BVL  
mim]nRd2v  
|NL$? %I  
private void processErrorCode(int nErrorCode) \ 3ha  
{ iGM-#{5  
System.err.println("Error Code : " + nErrorCode); evq *&.6\  
} dKhDO`.s  
*Z Aue.  
5X'[{'i,  
//停止文件下载 _.zW[;84b  
public void siteStop() {l! [{  
{ ^,@Rd\q  
bStop = true; jrG@ +" }  
for(int i=0;i<nStartPos.length;i++) %*zgN[/w  
fileSplitterFetch.splitterStop(); FK0nQ{uB"  
FSC74N/  
@32JMS<  
} nx8 4l7<  
} 6*Rz}RQ  
//负责部分文件的抓取 v:eVK!O  
**FileSplitterFetch.java L=?Yc*vg  
*/ 5) nm6sf  
package NetFox; T-uI CMEf  
NJwcb=*  
MX]<tR`  
import java.io.*; ^I@43Jy/  
import java.net.*; S+7>Y? B!  
nTyK Z(#u  
u+kXJ  
public class FileSplitterFetch extends Thread { = T!iM2  
[*Wq6n  
[PdatL2  
String sURL; //File URL ["kk.*&  
long nStartPos; //File Snippet Start Position 5l}v  
long nEndPos; //File Snippet End Position 5e6f)[}  
int nThreadID; //Thread's ID hVd% jU:  
boolean bDownOver = false; //Downing is over gM '_1zs U  
boolean bStop = false; //Stop identical }]'Z~5T  
FileAccessI fileAccessI = null; //File Access interface ">j}!n 8J  
^3^n|T7le  
twq!@C  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException !SMIb(~[z  
{ h:}oUr8   
this.sURL = sURL; Y7{IF X  
this.nStartPos = nStart; IR(qjm\V  
this.nEndPos = nEnd; =bi:<%"  
nThreadID = id; Dqs{ n?@n  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 bODCC5yL  
} :dc>\kUIv  
)k&<D*5s  
(3C::B=  
public void run() _Y?p =;  
{ Ys|tGU  
while(nStartPos < nEndPos && !bStop) D37N*9}  
{ BRLrD/8Le  
gG!L#J?  
YKlYo~fGN9  
try{ V>>"nf,YO  
URL url = new URL(sURL); !?,7Cu.5#6  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); zW+X5yK  
httpConnection.setRequestProperty("User-Agent","NetFox"); `A_CLVE  
String sProperty = "bytes="+nStartPos+"-"; b3N1SC:Wn  
httpConnection.setRequestProperty("RANGE",sProperty); kj{z;5-dl  
Utility.log(sProperty); J^m#984  
g 4G&  
@GNNi?EY  
InputStream input = httpConnection.getInputStream(); ~oWCTj-  
//logResponseHead(httpConnection); B4Ko,=pg  
G>& Tap>  
*](maF~%C  
byte[] b = new byte[1024]; O~?H\2S  
int nRead; M_lQ^7/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) pnl7a$z  
{ P:,'   
nStartPos += fileAccessI.write(b,0,nRead); ^cs:S-s  
//if(nThreadID == 1) % P .(L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *-'u(o  
} FrT.<3  
!W4A 9Th  
VRV*\*~$  
Utility.log("Thread " + nThreadID + " is over!"); 094~  s  
bDownOver = true; Aru=f~!  
//nPos = fileAccessI.write (b,0,nRead); _IYd^c  
} -}#=L@  
catch(Exception e){e.printStackTrace ();} 6Lj=%&  
} W}{RJWr  
} }tJR Bb  
X67^@~l  
=;A p+}  
//打印回应的头信息 ;n]GHqzY_  
public void logResponseHead(HttpURLConnection con) ldk (zAB.  
{ @-ps[b`z  
for(int i=1;;i++) UVa:~c$U4  
{ a@4 Z x  
String header=con.getHeaderFieldKey(i); Se~< Vpo  
if(header!=null) W}jel}:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Sp/t[\,'  
Utility.log(header+" : "+con.getHeaderField(header)); {x_SnZz&  
else 2MY-9(no  
break; ^F\RM4|,  
} b* (~8JxZ  
} m03D+@F  
[.:SV|AF#  
K ?uH Am  
public void splitterStop() ),cozN=NM  
{ 9lXjB_wG>  
bStop = true; 3lr9nBR  
} '^mCLfo0}  
r:N =?X`N  
3mef;!q  
} p6S{OUiG  
(B+CI%= D  
4f~ c# 0?  
/* 0n dk=V  
**FileAccess.java Hreu3N  
*//文件访问(定位,写) nUb0R~wr$G  
package NetFox; <9f;\+zA  
import java.io.*; -%f$$7  
Lsu_ f'p0  
_EHz>DJ9  
public class FileAccessI implements Serializable{ /Uxp5 b h  
mv1g2f+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 U)v){g3w)  
RandomAccessFile oSavedFile; z3Id8G&>  
long nPos; IhR;YM[K  
??5y0I6+  
~t=73 fwB  
public FileAccessI() throws IOException g}@W9'!  
{ U~3uu &/r  
this("",0); l7T@<V  
} Q+<{2oVz  
b6(LoN.  
fI<|]c}P&J  
public FileAccessI(String sName,long nPos) throws IOException 1Jm'9iy3  
{  {^8->V  
oSavedFile = new RandomAccessFile(sName,"rw"); K%jh 6c8  
this.nPos = nPos; OKo)p`BX  
oSavedFile.seek(nPos); yV.E+~y  
} U~CG(9  
3bsuE^,.@  
qQN|\u+co  
public synchronized int write(byte[] b,int nStart,int nLen) <Pn]{N  
{ wn1` 9  
int n = -1; %>io$o  
try{ ]S0tK  
oSavedFile.write(b,nStart,nLen); !#[B#DZc(  
n = nLen; Yq~$p Vgf  
} [[XbKg`"?  
catch(IOException e) hnYL<<AA  
{ Qr.SPNUFK  
e.printStackTrace (); r+RFDg/  
} B+VD53 V  
kO3N.t@n  
#jqcUno  
return n; e'l@M$^  
} uD=FTx  
ztEM>xsk  
5mqwNAv  
} w. c]   
wH0m^?a!3  
j+eto'  
/* Hd_W5R  
**SiteInfoBean.java vk><S|[n  
*/ ?9Hs,J  
package NetFox; Ss~yy0  
q?##S'  
OF1fS\P<>  
public class SiteInfoBean { QKHAN{hJ  
(5/>arDn  
Z1dLC'/b]  
private String sSiteURL; //Site's URL 5>x?2rp  
private String sFilePath; //Saved File's Path "3;b,<0  
private String sFileName; //Saved File's Name 2kfX_RK  
private int nSplitter; //Count of Splited Downloading File Vi*HG &DD  
$ S'~UbmYU  
*Y]()#?Gr  
public SiteInfoBean() u*6Y>_iA  
{//nSplitter的缺省值为5 DG-XX.:z  
//default value of nSplitter is 5 H&*KpOL  
this("","","",5); 7=@3cw H  
} s(0"r.  
(#K u`  
I]iTD  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ozOvpi:k3%  
{ BM>'w,$KL  
sSiteURL= sURL; vuoD~=z  
sFilePath = sPath; FzzV%  
sFileName = sName; U6xs'0  
this.nSplitter = nSpiltter; =\FV_4)  
@b3jO  
)|N_Q}  
} efrVF5,y?  
1m4Xl%KS>  
&UxI62[k  
public String getSSiteURL() ;^DG P  
{ f=--$o0U~  
return sSiteURL; #V-0-n,`  
} MO-7y p:K  
),rd7GB>  
Wz+7CRpeP  
public void setSSiteURL(String value) _ %gu<Ys  
{ G?dxLRy.do  
sSiteURL = value; lS96sjJp@  
} Bm$(4  
sNHxUI  
HP(dhsd<c  
public String getSFilePath() ] ^ s,  
{ :G[6c5j|V  
return sFilePath; xe@11/F  
} J.Fy0W@+k4  
J e"~/+  
)WH;G:$&"  
public void setSFilePath(String value) $mu*iW\{  
{ !m:rtPD'  
sFilePath = value; 8nE}RD7bx  
} vAcxca">S  
)cV*cDL1j  
&xLCq&j 1  
public String getSFileName() r WULv  
{ 2Fc>6]:*  
return sFileName; P}~nL  
} ^-2|T__  
C3:CuoE X  
%DhM}f  
public void setSFileName(String value) <! Z06  
{ z)F<{]%  
sFileName = value; I[w;soI  
} vhd+A  
\(`8ng]vs  
7'zXf)!  
public int getNSplitter() E+z"m|G  
{ W,f XHYst  
return nSplitter; %4,v2K  
} ^_c6Op<F  
!]C=5~B BI  
?rxq//S2  
public void setNSplitter(int nCount) f)19sjAJk  
{ 5j~1%~,#  
nSplitter = nCount; wfQ^3HL  
} d;hv_h  
} Xrr3KQaK&  
*W-:]t3CR  
EECuJ+T  
/* svvl`|n%  
**Utility.java 4A)@,t9+  
*/ oM(8'{S=  
package NetFox; KdXqW0nm  
-gB9476-  
F3e1&aK6{  
public class Utility { {1;R&  
2(AuhZ>  
<7 xX/Z}M  
public Utility() *!^l ZpF  
{ BcxALRWE  
|*( R$tX  
r (KAG"5  
} e+<'=_x {  
+3[8EM#g  
//线程睡眠 4o|<zn  
public static void sleep(int nSecond) jSMxba]  
{ CB^.N>'  
try{ YL&)@h  
Thread.sleep(nSecond); -dS@ l'$  
} _=_<cg y1u  
catch(Exception e) %%sJ+)  
{ l i) 5o  
e.printStackTrace (); 3IG<Ot9  
} 7yQw$zG,Iz  
} } 89-U  
<DZ$"t  
//日志 "1Y'VpKm(~  
public static void log(String sMsg) +~$pkxD"  
{ SS6K7  
System.err.println(sMsg); T^icoX=c4  
} C`=YGyj=TL  
w:+&i|H>  
]j0/.pG  
public static void log(int sMsg) xF6byTi  
{ z/,&w_8,:  
System.err.println(sMsg); N6HeZB" :  
} ~P BJ~j+G  
} 8d7 NESYl  
.: k6Kg  
G|YNShK4=9  
/* #z+?t  
**TestMethod.java H[RX~Xk2E  
*/ 8a3 EVc  
package NetFox; MML=J~1  
>hY.F/[  
1:!H`*DU&  
public class TestMethod { u|cP&^S  
s:3b.*t<  
`|2g &Vn  
public TestMethod() ~REfr}0  
{ ///xx/weblogic60b2_win.exe %j@@J\G!  
try{ xp}M5|   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); IGOEqUw*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); !/e*v>3u&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @'<=E AXe  
fileFetch.start(); l b;P&V  
} x\oSD1t,  
catch(Exception e){e.printStackTrace ();} EbG&[v  
]$=#:uf  
OT0IGsJ"'  
} Iz[ohn!f  
>a&IFi,j  
iK=QP+^VN  
public static void main(String[] args) ^YJ%^P  
{ /0o#V-E)  
new TestMethod(); @nAl*#M*D  
} 2 w6iqLr?  
} &->ngzg  
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