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http断点续传简单实现(java)

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/* A5 4u}  
**SiteFileFetch.java zJUT<%[U  
*/ +~,q"6  
package NetFox; )MoHY   
import java.io.*; S?D]P'<  
import java.net.*; B !rb*"[  
_o+OkvhU  
h:FN&E c}  
public class SiteFileFetch extends Thread { d}Y#l}!E6  
A5%Now;.cf  
4[%_Bnv#AJ  
SiteInfoBean siteInfoBean = null; //文件信息Bean N693eN!  
long[] nStartPos; //开始位置 +J A\by  
long[] nEndPos; //结束位置 )`gxaT>&l  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 <9$Pl%:  
long nFileLength; //文件长度 :zO;E+s  
boolean bFirst = true; //是否第一次取文件 'b>3:&  
boolean bStop = false; //停止标志 X%;4G^%ZI  
File tmpFile; //文件下载的临时信息 vYo~36  
DataOutputStream output; //输出到文件的输出流 ~Xr[d07bC  
dV*9bDkM/  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) *lheF>^  
public SiteFileFetch(SiteInfoBean bean) throws IOException {D,- Whi  
{ 8LuU2Lo  
siteInfoBean = bean; m>!o Yy_  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); oJE<}~_k  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); AnZy o a  
if(tmpFile.exists ()) ye}86{l  
{ v!n|X7  
bFirst = false; QMDkkNK  
read_nPos(); 2J3y 1  
} R-4#y%k<  
else fX1Ib$v  
{ !9V; 8g  
nStartPos = new long[bean.getNSplitter()]; /7.//klN  
nEndPos = new long[bean.getNSplitter()]; 2@N-#x '  
} DoICf1  
|a'$v4dCF  
T7Ju7_q}  
rTST_$"_6  
} dn_l#$ U  
}p8iq  
LW!4KA]  
public void run() ScT{Tb]9bt  
{ 85A7YraL  
//获得文件长度 S]&aDg1y}  
//分割文件 (H]NL   
//实例FileSplitterFetch :j32 :/u  
//启动FileSplitterFetch线程 I(/*pa?m{  
//等待子线程返回 JM*!(\Y  
try{ a`U/|[JM  
if(bFirst) g/w <T+v  
{ |#(y?! A^  
nFileLength = getFileSize(); g6?5  
if(nFileLength == -1) @)ls+}=Y  
{ Juk'eH2^s  
System.err.println("File Length is not known!"); ,OMdLXr  
} sWVapu p?  
else if(nFileLength == -2) V'K:52  
{ owA.P-4  
System.err.println("File is not access!"); PM)nw;nS  
} I 6L3M\+-  
else tU.~7f#+A  
{ r\C"Fx^  
for(int i=0;i<nStartPos.length;i++) 6R#igLm  
{ GgtYO4,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); (De>k8  
} JL7;l0#  
for(int i=0;i<nEndPos.length-1;i++) wEU=R>j.  
{ T#&X7!4  
nEndPos = nStartPos[i+1]; X7*fmD=Uy  
} NjO_Y t  
nEndPos[nEndPos.length-1] = nFileLength; 2r@9|}La  
} /1xBZf rN  
} ZT<VDcP{  
\ #la8,+9  
NE| Q0g  
//启动子线程 CsjrQ-#9yn  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; zNg[%{mz  
for(int i=0;i<nStartPos.length;i++) Q5Epq sKyC  
{ Ieh<|O,-C  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |z0% q2(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), KC8  
nStartPos,nEndPos,i); Dnd  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); RW<4",  
fileSplitterFetch.start(); Zlrbd  
} V \/Qik{h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7ab'q&Y[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); AN)r(86L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "1 UpoF'w  
nEndPos = " + nFileLength); [i_evsUj?  
// fileSplitterFetch[nPos.length-1].start(); 27}0  
.S]*A b  
E,Xl8rC  
//等待子线程结束 VeOM `jy  
//int count = 0; t~":'le`zr  
//是否结束while循环 0#~k)>(7lR  
boolean breakWhile = false; _\{/#J;lN  
C* 0Z F  
wZ=@0al  
while(!bStop) .fS{j$  
{ 7JBr{3;eS  
write_nPos(); Ve<f}  
Utility.sleep(500); u~~ ~@p  
breakWhile = true; .9UrWBW\I  
Oc5f8uv  
01NP  
for(int i=0;i<nStartPos.length;i++) UUF]45t>  
{ t[MM=6|Wb  
if(!fileSplitterFetch.bDownOver) [&(~1C|C  
{ KDj/S-S  
breakWhile = false; #c~- 8=  
break; "Jdi>{o8  
} nQ{~D5y,,  
} q#\B}'I{  
if(breakWhile) b1%w+*d<z  
break;  i(V  
'}-QZ$|*  
ubc k{\.  
//count++; qggRS)a  
//if(count>4) FtlJ3fB@  
// siteStop(); z 0F55<i  
} {aUv>T"c  
9#kk5)J  
$x#qv1  
System.err.println("文件下载结束!"); :z6?  
} *:`fgaIDa  
catch(Exception e){e.printStackTrace ();} .')^4\  
} GB,ub*|  
{\|XuCF#  
a>+m_]*JZ  
//获得文件长度 9E|QPT  
public long getFileSize() ~RZN+N  
{ %/ :&L+q  
int nFileLength = -1; v?n# C  
try{ 2X(2O':Uc  
URL url = new URL(siteInfoBean.getSSiteURL()); @X=sfygk  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Z Z c^~  
httpConnection.setRequestProperty("User-Agent","NetFox"); f lt'~fe  
}iLi5Qkx  
=\\rk,F  
int responseCode=httpConnection.getResponseCode(); *z_`$Y  
if(responseCode>=400) Yq:/dpA_  
{ b{X.lz0  
processErrorCode(responseCode); uzLm TmM+  
return -2; //-2 represent access is error jaMpi^C  
} v "[<pFj^  
A5[kYD,_  
Lmw)Ts>  
String sHeader; 6F%6]n  
% 3fpIzm  
^9YS dFH/  
for(int i=1;;i++) !~ j9Oc^  
{ 0rif,{"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j J54<.D  
//Utility.log(in.readLine()); r]kks_!Z  
sHeader=httpConnection.getHeaderFieldKey(i); brL u~]I  
if(sHeader!=null) FRQkD%k  
{ 0/cgOP!^  
if(sHeader.equals("Content-Length")) )ub!tm  
{ E^~ {thf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); &]anRT#  
break; (X (:h\^  
} ]eTp?q%0  
} d[E= HN  
else ZY;g)`E1  
break; KCqz]  
} Z$35`:x&h  
} ur]WNk8bN  
catch(IOException e){e.printStackTrace ();} ':utU1dL  
catch(Exception e){e.printStackTrace ();} O_5;?$[m  
'SIc2H  
v v   
Utility.log(nFileLength); 2"o <>d  
=s S=  
D^{jXNDNO  
return nFileLength; Gr3 q  
} n9 Jev_!A  
&((04<@e  
4dh> B>Q  
//保存下载信息(文件指针位置) 9g$fFO  
private void write_nPos() `"$9L[>  
{ D9n+eZ  
try{ J,=^'K(  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^q<EnsY  
output.writeInt(nStartPos.length); \;"S>dg  
for(int i=0;i<nStartPos.length;i++) 0bGQO&s [  
{ fo I:`]2"*  
// output.writeLong(nPos); cr^R9dv  
output.writeLong(fileSplitterFetch.nStartPos); V{rQ@7SE  
output.writeLong(fileSplitterFetch.nEndPos); *Ym+xu_5  
} 7 S%`]M4;  
output.close(); O:dUzZR['  
} ^;Yjs.bI`F  
catch(IOException e){e.printStackTrace ();} **ls 4CE<  
catch(Exception e){e.printStackTrace ();} ;uuBX0B  
} Q%t _Epe  
==bT0-M.~  
E7]a#  
//读取保存的下载信息(文件指针位置) G2J4N2hu  
private void read_nPos() fl*49-d  
{ L_IvR 4:j~  
try{ >lugHF$G  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); X`I=Z ysB  
int nCount = input.readInt(); &2W`dEv]?  
nStartPos = new long[nCount]; }BCxAwD4  
nEndPos = new long[nCount]; n$"B F\eM  
for(int i=0;i<nStartPos.length;i++) !,*Uvs@b  
{ 2}ywNVS  
nStartPos = input.readLong(); L_>LxF43  
nEndPos = input.readLong(); McvLU+  
} iyMoLZ5  
input.close(); ;i3C  
} <Oj'0NK-  
catch(IOException e){e.printStackTrace ();} ?j} Fxr  
catch(Exception e){e.printStackTrace ();} oMN Qv%U  
} e#?rK=C?9  
4{" v  
"+BuFhSLf  
private void processErrorCode(int nErrorCode) hrbeTtqi  
{ Z0Qh7xWve  
System.err.println("Error Code : " + nErrorCode); "K*^%{  
} c*)PS`]t  
:NWrbfz  
#YLI"/Kn  
//停止文件下载 QFEc?sEe  
public void siteStop() T{ /\q 5  
{ PMiG:bM  
bStop = true; (DTkK5/%  
for(int i=0;i<nStartPos.length;i++) ;B"S*wYMN  
fileSplitterFetch.splitterStop(); 4rNuAK`2  
BCr*GtR)W  
p2 m`pT  
} &>hln<a>  
} )"^ )Nk  
//负责部分文件的抓取 b"~Ct}6f  
**FileSplitterFetch.java NW?h~2  
*/ 6;}FZ  
package NetFox; g0RfvR  
>zv}59M  
Bj\oo+L/  
import java.io.*; /909ED+)>9  
import java.net.*; ~ponYc.Y  
a]R1Fi0n  
0S>U_#-  
public class FileSplitterFetch extends Thread { T@DT|lTI  
\H.1I=<  
xA"7a  
String sURL; //File URL ZN(@M@}  
long nStartPos; //File Snippet Start Position `z`"0;,7S  
long nEndPos; //File Snippet End Position gz"I=9  
int nThreadID; //Thread's ID n6 AP6PK7  
boolean bDownOver = false; //Downing is over }9(:W</}  
boolean bStop = false; //Stop identical U~{sJwB  
FileAccessI fileAccessI = null; //File Access interface nsV;6^>  
KEvT."t  
0p ZX_L'  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException HVcd< :g0  
{ /'>#1J|TlK  
this.sURL = sURL; dK?vg@|'  
this.nStartPos = nStart; $~2qEe.h  
this.nEndPos = nEnd; o_ SR  
nThreadID = id; x-ShY&k  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 C<\O;-nHH  
} (8OaXif  
\^rAH@  
GOhGSV#  
public void run() rz3!0P!"K  
{ 0 6S-3bis  
while(nStartPos < nEndPos && !bStop) &5F@u IA  
{ 2x&mJ}o#k  
m>@ *-*8k  
m\xE8D(,  
try{ ~T<o?98  
URL url = new URL(sURL); Td>Lp=0rU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); q!+m, !M  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5//.q;z  
String sProperty = "bytes="+nStartPos+"-"; wWR9dsB.;  
httpConnection.setRequestProperty("RANGE",sProperty); OTe0[p6v  
Utility.log(sProperty); Iz<}>J B  
bC@9 */i  
tMWsgK.B  
InputStream input = httpConnection.getInputStream(); S+EC!;@Xg  
//logResponseHead(httpConnection); Dk XB  
NbtNu$%t  
+TnRuehtk  
byte[] b = new byte[1024]; 4^mpQ.]lO  
int nRead; 2nGQD{  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2|n~5\K|t  
{ $pm5G} .  
nStartPos += fileAccessI.write(b,0,nRead); k6vY/)-S  
//if(nThreadID == 1) 8s_'tw/{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3tlA! e  
} b{o%`B*  
E%vG#  
Gmi$Nl!~  
Utility.log("Thread " + nThreadID + " is over!"); j7|r^  
bDownOver = true; :3# t;  
//nPos = fileAccessI.write (b,0,nRead); _ ecKX</Q  
} ^Fr82rJs  
catch(Exception e){e.printStackTrace ();} )J"Lne*"  
} p Rn vd|  
} v]tbs)x;h  
C=6Vd  
@,RrAL }|  
//打印回应的头信息 `4'['x  
public void logResponseHead(HttpURLConnection con) TrHz(no  
{ 4epE!`z_&  
for(int i=1;;i++) ?>V4pgGCE  
{ gZ*8F|sg  
String header=con.getHeaderFieldKey(i); lth t'|  
if(header!=null) }-:s9Lt  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); n 4:Yc@,  
Utility.log(header+" : "+con.getHeaderField(header)); (0Xgv3wd  
else _[8BAm  
break; xA-O?s"CY  
} ~7tG%{t%  
} at@B>Rb  
9WaKsdf  
(#WE9~Sru  
public void splitterStop() tc%?{W\  
{ _N5$>2  
bStop = true; cCd2f>EHw  
} ^h z4IZ^  
ceDe!Iu  
` gIlS^Q  
} H[ DrG6GA  
oGi;S="I  
H1H+TTZr  
/* &}P{w  
**FileAccess.java E4^zW_|xE  
*//文件访问(定位,写) R&13P&:g  
package NetFox; fdIk{o  
import java.io.*; 1>$ fLbmkI  
0s"g%gq|  
^ 1rw\Zp  
public class FileAccessI implements Serializable{ }VlX!/42  
IG?044Y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Fh u(u  
RandomAccessFile oSavedFile; .` z](s  
long nPos; x?0ZzB),  
uUXvBA?l  
+@wa?"  
public FileAccessI() throws IOException I4kN4*d!N,  
{ `}/&}Sp  
this("",0); 9*gD;)!  
} {umdW x.*  
JHpaDy*  
<S'5`-&  
public FileAccessI(String sName,long nPos) throws IOException >r] bfN,  
{ Z `FqC  
oSavedFile = new RandomAccessFile(sName,"rw"); `<>Emc8Z  
this.nPos = nPos; './j<2|;U  
oSavedFile.seek(nPos); Gma)8X#  
} VU7x w  
|A".Mo_5  
?ic7M  
public synchronized int write(byte[] b,int nStart,int nLen) &K@2kq,  
{ &DC o;Ij;  
int n = -1; XJl2_#  
try{ @[M5$,"  
oSavedFile.write(b,nStart,nLen); Ay'2! K,I  
n = nLen; V:*QK,  
} "f|\":\  
catch(IOException e) ^a~^$PUqI  
{ tmF->~|  
e.printStackTrace (); D&q-L[tA@  
} _ F&BSu  
J_A+)_  
wjGD[~mB  
return n; ,"!t[4p=f  
} hO3>Gl5<  
`N%q^f~  
f8um.Xnp6  
} }ie\-V  
swv 1>52{  
)8Defuxk  
/* "*O(3L.c-  
**SiteInfoBean.java sFaboI  
*/ =ja(;uC  
package NetFox; D6 B(6 5Y  
k^-HY[Q9  
,B ]kX/W  
public class SiteInfoBean { B.nq3;Y  
j}NGyS" =  
{?c `0C  
private String sSiteURL; //Site's URL K@u\^6419  
private String sFilePath; //Saved File's Path A7!!kR":  
private String sFileName; //Saved File's Name uY+N163i  
private int nSplitter; //Count of Splited Downloading File ydFZ$W_}w  
i,jPULzyjk  
)*_4=-8H  
public SiteInfoBean() z7X[$T$V  
{//nSplitter的缺省值为5 yZJR7+  
//default value of nSplitter is 5 zb/w^~J_i  
this("","","",5); .\1{>A  
} A%S6&!I:(  
g:bw;6^ u  
/I@nPH<y  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,<]X0;~oB  
{ }lzUl mRTe  
sSiteURL= sURL; GrWzgO  
sFilePath = sPath; k[3J5 4`g1  
sFileName = sName; oW]~\vp^0  
this.nSplitter = nSpiltter; .0$$H"t  
-' 7I|r  
595P04  
} gKK*` L~  
-DgJkyt+<  
 w+<`>  
public String getSSiteURL() @?,iy?BSG  
{ IN2FO/Y@  
return sSiteURL; 9(`d h  
} nRKh|B)  
G?\\k[#,&  
\ UCOe  
public void setSSiteURL(String value) Ms8& $  
{ QAiont ,!  
sSiteURL = value; `4V_I%lJ&  
} y#-mj,e  
v6B}ov[Y2  
 3LKL,z  
public String getSFilePath() e)I-|Q4^%  
{ $J8?!Xg  
return sFilePath; fz H$`X'M  
} S+LE ASOr  
XI#1)  
=m{]Xep  
public void setSFilePath(String value) P9j[ NEV  
{ 8. 9TWsZ  
sFilePath = value; A1`y_ Aj  
} Q9v OY8  
w#EP`aM2$=  
|y+<|fb,a  
public String getSFileName() `/en&l  
{ -X#Zn>#  
return sFileName; =bt/2 nPV  
} {ir8n731p  
'xO5Le(=M  
>U/ m/H'  
public void setSFileName(String value) #sLyU4QV  
{ )%D2JC  
sFileName = value; @SH%l]  
} x^_(gve:  
JVO,@~~  
7`,A]":;  
public int getNSplitter() 7}+U;0,)  
{ xE+Nz5F  
return nSplitter; 3R!?r^h  
} UOTM>d1P  
d^5OB8t  
kaBP& 6|Z  
public void setNSplitter(int nCount) "o+E9'Dm  
{ I"/p^@IX  
nSplitter = nCount; Er; @nOyD  
} h*J=F0KM  
} hdZ{8 rP  
D,FX&{TYU  
p-d2HXo  
/* CF|c4oY82  
**Utility.java 6|q\ M  
*/ Qs24b  
package NetFox; NYS |fa  
{Vy2uow0  
}cDw9;~D  
public class Utility { laVqI|0q  
[v7)xV@c  
5&}~W)"9  
public Utility() Y](kMNUSg  
{ kjW Y{7b!  
PGTi-o}  
}A@op+0E  
} .L;M-`^  
l ;TWs_N  
//线程睡眠 ^HpUbZpat)  
public static void sleep(int nSecond) 2)O-EAn  
{ mj\]oWS7d  
try{ a`]Dmw8@  
Thread.sleep(nSecond); "AH1)skB:  
} oqu; D'8  
catch(Exception e) S.,om;`  
{ N_AAhD  
e.printStackTrace (); `~${fs{-`/  
} Tk(ciwB  
} "P4#Q_  
fTn  
//日志 mJjd2a"vi  
public static void log(String sMsg) LQy`,-&  
{ OMaG*fb=  
System.err.println(sMsg); h_O6Z2J1  
} p[kEFE,%  
1: cD\  
@.JhL[f  
public static void log(int sMsg) 9~AAdD  
{ $+#Lq.3,  
System.err.println(sMsg); mGf@J6wGz  
} _0Mt*]L }  
} Q& p'\6~  
XYeuYLut  
VK7lm|J+  
/* Q]9g  
**TestMethod.java xp+Z%0D  
*/ Tyc`U&  
package NetFox; 9rO,h|L   
eVDO]5?  
#;l~Y}7'  
public class TestMethod { u ##.t  
s@Q, wa(  
+YS0yTWeX  
public TestMethod() ^ +e5 M1U=  
{ ///xx/weblogic60b2_win.exe l$j/Ye]  
try{ \YV`M3O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Vn4y^_H  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); })zYo 7  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 3bMQ[G  
fileFetch.start(); D_n(T ')  
} S"*M9*8  
catch(Exception e){e.printStackTrace ();} /hx|KC&:e  
!KYX\HRW  
4T]n64Yid  
} fT:a{  
p>GTFXEi6  
:E$<!q  
public static void main(String[] args) 9DAk|K  
{ STfcx] L  
new TestMethod(); @' V=Vr  
} Klw\  
} 4 w$f-   
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