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http断点续传简单实现(java)

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/* %\I.DEYH  
**SiteFileFetch.java L|\Diap  
*/ ~:Mm<*lL%  
package NetFox; ( 3;`bvYH"  
import java.io.*; T|bZ9_?+2  
import java.net.*; 28oJFi]  
\ja `c)x  
t)r1"oA  
public class SiteFileFetch extends Thread { Dl A Z"C  
jdlG#j-\  
/s`;9)G]9  
SiteInfoBean siteInfoBean = null; //文件信息Bean LdEE+"Jw  
long[] nStartPos; //开始位置 Z*eoA  
long[] nEndPos; //结束位置 d~`-AC+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 eqhAus?)  
long nFileLength; //文件长度 ]>8)|]O6n  
boolean bFirst = true; //是否第一次取文件 =l,#iYJP8  
boolean bStop = false; //停止标志 ,sI35I J  
File tmpFile; //文件下载的临时信息 N-QCfDao  
DataOutputStream output; //输出到文件的输出流 %U?)?iZdL  
)U5u" ]9~  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 4B$bj `h  
public SiteFileFetch(SiteInfoBean bean) throws IOException U~/ID  
{ 6"%2,`Nu  
siteInfoBean = bean; #r}uin*jD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); kzi|$Gs<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); zlkWU  
if(tmpFile.exists ()) @L8;VSI  
{ Z4@y?f v7s  
bFirst = false; xA-jvu9@  
read_nPos(); 0;cuX@A/a?  
} bNs[O22  
else ke6n/ h5`  
{ g;G5 r&T  
nStartPos = new long[bean.getNSplitter()]; 6b#~;  
nEndPos = new long[bean.getNSplitter()]; ;)|nkI  
} dz,+tR~  
jw4TLc7p  
OjATSmZ@@  
FmI;lVF0j  
} <kbnu7?a*  
q+%!<]7X  
UkfA}b^@v  
public void run() b1)\Zi  
{ v, 0<9!'v  
//获得文件长度 7d9Z/J@>  
//分割文件 (hsZ  
//实例FileSplitterFetch ]]y[t|6  
//启动FileSplitterFetch线程 PbN3;c3  
//等待子线程返回 hBy*09Sv  
try{ 6t$N78U  
if(bFirst) uO"8aD`W  
{ e~ BJvZ}Q  
nFileLength = getFileSize();  mn`5pha  
if(nFileLength == -1) y5%5O xB  
{ m1y `v"  
System.err.println("File Length is not known!"); +{*)}[w{x  
} 5rN7':(H!%  
else if(nFileLength == -2) Gh+f1)\FA"  
{ r?$ &Z^  
System.err.println("File is not access!"); acae=c|X  
} }.t^D|  
else ^O \q3HA_4  
{ :D4];d>1  
for(int i=0;i<nStartPos.length;i++) 8]]@S"ZM,\  
{ DaDUK?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); O! (85rp/  
} JZw^ W{  
for(int i=0;i<nEndPos.length-1;i++) DaCblX  
{ [yF^IlSs  
nEndPos = nStartPos[i+1]; :`5;nl63  
} |0]YA  
nEndPos[nEndPos.length-1] = nFileLength; dk:xnX%  
} rXDJ:NP  
} ;-Ado8  
`u=oeM :  
5"uNj<.V  
//启动子线程 y($EK(cb  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 3P`WPph  
for(int i=0;i<nStartPos.length;i++) G<fS (q  
{ 6VFirLd  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), UOJ*a1BM  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), kwc*is  
nStartPos,nEndPos,i); 23k)X"5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ]_\AHnJ  
fileSplitterFetch.start(); q|Fjm]AF  
} C (U  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `GS cRhbh  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W1`Dx(g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", B'#4;R!8P=  
nEndPos = " + nFileLength); iLQSa7  
// fileSplitterFetch[nPos.length-1].start(); ->3uOF!q  
F {/>u(@3  
!G[f[u4Zg  
//等待子线程结束 [9J:bD  
//int count = 0; Lz?*B$h  
//是否结束while循环 bw0 20@O*  
boolean breakWhile = false; Z,SY N?@  
(H2ylMpQt  
GI?PGAT  
while(!bStop) Eo Ko   
{ LS{bg.e  
write_nPos(); @o60 c  
Utility.sleep(500); M6&~LI.We=  
breakWhile = true; wePI*."]  
`ReGnT[  
G LoiH#R  
for(int i=0;i<nStartPos.length;i++) nPcxknl(pd  
{ a^(2q{*  
if(!fileSplitterFetch.bDownOver) n 3h^VQ*]G  
{ <8*A\&  
breakWhile = false; <5M_EJp  
break; CuIqh BW!  
} %uj[`  
} C/bxfp{?  
if(breakWhile) 1y 1_6TZ+  
break; Q7L)f71i  
*/4tJ G1U  
~Po\ En  
//count++; " cNg :  
//if(count>4) WejyYqr34-  
// siteStop();  k~{Fnkt  
} > n1h^AW  
We\KDU\n  
#jOOsfH|k  
System.err.println("文件下载结束!"); dV)Y,Yx0${  
} X=JFWzC  
catch(Exception e){e.printStackTrace ();} J0Jr BXCh  
} k&yQ98H$K"  
:MK:TJV  
1E8$% 6VV  
//获得文件长度 uL bp.N8  
public long getFileSize() (VfwLo>#  
{ 6={IMkmA  
int nFileLength = -1; u2 Y N[|V  
try{ re]%f"v:5  
URL url = new URL(siteInfoBean.getSSiteURL()); Ndo}Tk!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J_|7$ l/  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4C6=77Jr  
=Y/}b\9`T  
&ycjSBK  
int responseCode=httpConnection.getResponseCode(); 0T(O'v}.  
if(responseCode>=400) E1#H{)G  
{ K4_~ruhr  
processErrorCode(responseCode); N`f!D>b:dn  
return -2; //-2 represent access is error c$.UE  
} FMoJ"6Q  
Ih(:HFRMq6  
$|rCrak;  
String sHeader; ={\![{L  
DE5d]3B  
z'?SRK5+  
for(int i=1;;i++) I; ^xAd3G  
{ ?Y%}(3y  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); @<|6{N<  
//Utility.log(in.readLine()); sf fV.cC`  
sHeader=httpConnection.getHeaderFieldKey(i); "v@);\-V  
if(sHeader!=null) 6euR'd^Qi  
{ 1]"D%U=  
if(sHeader.equals("Content-Length")) 2@rp<&s  
{ WfRVv3Vm  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [|y`y%  
break; W&HF?w}s  
} uPI v/&HA  
} K/!/M%GB6  
else )gr}<}X)B  
break; 0Wjd-rzc,  
} m"5{D*|  
} ~u};XhZ  
catch(IOException e){e.printStackTrace ();} sq6>DuBZz  
catch(Exception e){e.printStackTrace ();} T@B"BoKU  
7We?P,A\;  
su,`q  
Utility.log(nFileLength); , - QR  
q s v+.aW  
@P*ylB}?Q  
return nFileLength; ~o:rM/!Ba  
} =s`XZkh  
,?C|.5  
J>&[J!>r  
//保存下载信息(文件指针位置) CR%D\I$o  
private void write_nPos() c$@`P  
{ d,zp `S  
try{ VEL:JsY  
output = new DataOutputStream(new FileOutputStream(tmpFile)); FX{ ~"  
output.writeInt(nStartPos.length); =n> iQS  
for(int i=0;i<nStartPos.length;i++) 3X,]=f@_  
{ vEu Ka<5  
// output.writeLong(nPos); xylpiSJ  
output.writeLong(fileSplitterFetch.nStartPos); E~'q?LJOB  
output.writeLong(fileSplitterFetch.nEndPos); 7h(HG?2Y  
} ) ~ l\  
output.close(); VI(RT-S6  
} >`<Ued  
catch(IOException e){e.printStackTrace ();} Mr$# e  
catch(Exception e){e.printStackTrace ();} ~sZqa+jB0  
} Mi;}.K0J  
K#_~ !C4L  
:&xz5c`"04  
//读取保存的下载信息(文件指针位置) D-'i G%)kA  
private void read_nPos() ev~dsk6k  
{ m"96:v  
try{ ;M%oQ> ].[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); u)<Ysx8G  
int nCount = input.readInt(); !Sh^LYqn  
nStartPos = new long[nCount]; pYYqGv^oa  
nEndPos = new long[nCount]; kqj;l\N  
for(int i=0;i<nStartPos.length;i++) ck(CA(_  
{ <f7?P Ad  
nStartPos = input.readLong(); <9Lv4`]GU5  
nEndPos = input.readLong(); 5W*7qD[m  
} O<}ep)mr  
input.close(); JoZqLy!@  
} &{X{36  
catch(IOException e){e.printStackTrace ();} 5F'%i;)oq  
catch(Exception e){e.printStackTrace ();} Yh}zt H  
} LEYWH% y  
EJ WOXxU  
 f$:7A0  
private void processErrorCode(int nErrorCode)  !7 ei1  
{ ( rA\_FOJ  
System.err.println("Error Code : " + nErrorCode); Mfnlue](  
} OpWeW  
yw;ghP;  
UN cYu9[  
//停止文件下载 ^n\9AE3  
public void siteStop() AZh@t?)  
{ l=oN X"l=  
bStop = true; ZA *b9W  
for(int i=0;i<nStartPos.length;i++) {DKXn`V  
fileSplitterFetch.splitterStop(); <C7M";54-  
!yoSMI-  
)e4WAlg8c  
} O"_erH\nk  
} bBkm]  >  
//负责部分文件的抓取 !^c:'I>~  
**FileSplitterFetch.java qZT 4+&y  
*/ 3MNhH  
package NetFox; 4+ASw N9  
oUW )H  
nz,Mqol  
import java.io.*; 8zP:*|D  
import java.net.*; ^CowJ(y(  
OaD Alrm  
Cfv L)f  
public class FileSplitterFetch extends Thread { _hAj2%SL  
)GiFkG  
6vD]@AF  
String sURL; //File URL mF6@Y[/B  
long nStartPos; //File Snippet Start Position g@S@d&9  
long nEndPos; //File Snippet End Position uM6CG0  
int nThreadID; //Thread's ID W~XV  
boolean bDownOver = false; //Downing is over JcvHJ0X~a  
boolean bStop = false; //Stop identical A }>|tm7|  
FileAccessI fileAccessI = null; //File Access interface 9[epr+f  
_aXP ;kFMi  
w0a+8gexi  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "e1{V8 4  
{ ]y1$F Ir+  
this.sURL = sURL; -Z`(? k  
this.nStartPos = nStart; 8]cv&d1f  
this.nEndPos = nEnd; d&PE,$XC  
nThreadID = id; "?2  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Bo](n*i  
} h/0<:eZ*  
&y#\1K  
D-TNFYYy2  
public void run() EuKrYY]g  
{ nhVK?  
while(nStartPos < nEndPos && !bStop) 38x[Ad4%  
{ b:}wR*Adc  
OEy:#9<'  
5p]urfN-f  
try{ 2-"Lxe65f  
URL url = new URL(sURL); $4$?M[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z. _C*c  
httpConnection.setRequestProperty("User-Agent","NetFox"); G:h;C].  
String sProperty = "bytes="+nStartPos+"-"; SxLHFN]  
httpConnection.setRequestProperty("RANGE",sProperty); 7})!>p )  
Utility.log(sProperty); J[& 7,}  
{L-{Y<fke  
|*]X\UE  
InputStream input = httpConnection.getInputStream(); C)&gL=O*$  
//logResponseHead(httpConnection); ~ X]"P4 u  
&dZ.+#8r  
vjs|!O=oH  
byte[] b = new byte[1024]; y0&V$uv/  
int nRead; ;H m-,W  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) VuO)  
{ $ sA~p_]  
nStartPos += fileAccessI.write(b,0,nRead); xvdnEaWe$  
//if(nThreadID == 1) }OX>(  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T_(e(5  
} >"sKfiM)b  
 hZss  
xdbu|fC  
Utility.log("Thread " + nThreadID + " is over!"); r$3~bS$]  
bDownOver = true; Q8gdI  
//nPos = fileAccessI.write (b,0,nRead); {R1Cxt}  
} Ivt)Eg  
catch(Exception e){e.printStackTrace ();} ^;bGP.!p  
} X('Q;^`  
} R+ #.bQg  
&t.>^7ELF  
0()9vTY+  
//打印回应的头信息 Skk3M?  
public void logResponseHead(HttpURLConnection con) VvM U)  
{ Tl/Dq(8JH  
for(int i=1;;i++) _!CvtUU0Vv  
{ ,39$iHk  
String header=con.getHeaderFieldKey(i); E3.W#=o  
if(header!=null) e~2*> 5\:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); y?R <g^A  
Utility.log(header+" : "+con.getHeaderField(header)); .U(SkZ`6  
else +}G>M=t::  
break; k.? T.9  
} 8tFyNl`c  
} d~z<,_ r5c  
%. 6?\w1e  
_>?8eC]4a  
public void splitterStop() `>Kk;`  
{ "'H7F ,k'  
bStop = true; k>z-Zg  
} "]\":T  
BorfEv} SN  
P+zI9~N[  
} +DV6oh  
C)3$";$5)  
h}B# 'e  
/* 6 peM4X  
**FileAccess.java woH3?zR  
*//文件访问(定位,写) }Bod#|`  
package NetFox; $O]E$S${  
import java.io.*; ae(]9VW  
f@. Q%+!4  
G/RheH G  
public class FileAccessI implements Serializable{ $qyM X[  
>G3 J3P(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 OTFu4"]M  
RandomAccessFile oSavedFile; Ci#5@Q9#w  
long nPos; M3ZJt'|  
aab4c^Ms=  
Y ,pS/  
public FileAccessI() throws IOException %},S#5L3  
{ XY t8vJ  
this("",0); JpHsQ8<  
} v,.n/@s|X  
MPEBinE?  
3v3Va~fm`  
public FileAccessI(String sName,long nPos) throws IOException 6~Oje>w;  
{ d<cbp [3F  
oSavedFile = new RandomAccessFile(sName,"rw"); [\M?8R$)  
this.nPos = nPos; AFhG{G'W  
oSavedFile.seek(nPos); 8/kO9'.P  
} -0W;b"]+A  
,+JAwII>O  
5%Q!R%  
public synchronized int write(byte[] b,int nStart,int nLen) XW19hG  
{ <%!@cE+y  
int n = -1; ;%U`P8b!  
try{ ,0~'#x>  
oSavedFile.write(b,nStart,nLen); |OC6yN *P)  
n = nLen; wk3yz6V2  
} ]@'YlPU  
catch(IOException e) ";jhj:Xj  
{ 7~IAgjo,@  
e.printStackTrace (); ICGBU>Db  
} FNUue  
|ey6Czm  
7==Uoy*O  
return n; 4g6d6~098;  
} eX=W+&lj  
>FY`xl\m}<  
6l50IWj,T  
} rc$G0O  
[1E u6X6  
nJ6bC^*)U  
/* )37|rB E  
**SiteInfoBean.java C9~CP8  
*/ LTi0,03l<  
package NetFox; LOp<c<+aW  
$FD0MrB_+  
N[AX29  
public class SiteInfoBean { . [C ~a  
xL mo?Y*  
fFsA[@5tul  
private String sSiteURL; //Site's URL 2"NJt9w  
private String sFilePath; //Saved File's Path TEY%OI zU+  
private String sFileName; //Saved File's Name .~Td /o7  
private int nSplitter; //Count of Splited Downloading File L"AZ,|wIk  
"_9Dau$  
R7vO,kZ6Q  
public SiteInfoBean() Xbfn@7m  
{//nSplitter的缺省值为5 %rYd=Ri  
//default value of nSplitter is 5 M[SWMVN{  
this("","","",5); :]:q=1;c  
}  Qq>M}  
+Ge-!&.;A  
)y._]is)b  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) x%0Q W  
{ 40mgB4I  
sSiteURL= sURL; F(mm0:lT  
sFilePath = sPath; )/Ul" QF  
sFileName = sName; c\7~_w2  
this.nSplitter = nSpiltter; 0*x  
3PPN_Z  
g&&5F>mF  
} ]M#_o]  
`N$<]i]s5  
gLU #\d]  
public String getSSiteURL() 9z,V]v=  
{ .%.J Q  
return sSiteURL; >/GVlXA'  
} tvavI9  
'`^`NI`  
iku) otUc  
public void setSSiteURL(String value) aO6w :IO  
{ {4\(HrGNk  
sSiteURL = value; .t$~>e .  
} NZCPmst  
bfhap(F~(e  
hjs[$ ,1  
public String getSFilePath() fp u^  
{ K8f;AK  
return sFilePath; Wu?4oF  
} 9*U3uyPi  
Yq}(O<ol  
p%ek)tT  
public void setSFilePath(String value) \$W>@w0  
{ n}}$-xl  
sFilePath = value; rISg`-  
} p78X,44xg  
>Ta|#]{  
{L4ta~2/T  
public String getSFileName() ]gx]7  
{ CM|?;PBuv  
return sFileName; c/%i,N\5  
} cba ~  
73 ix4C  
09HlL=0q  
public void setSFileName(String value) AQ7w5}g+V  
{ %dw@;IZ#8{  
sFileName = value; fIWOo >)D  
} \ ?sM  
~QQi{92  
/ p}^ Tpu  
public int getNSplitter() kzcl   
{ H}Z\r2  
return nSplitter; N D`?T &PK  
} Y`.FSs  
B}Qpqa=_c  
BUvE~l.,|  
public void setNSplitter(int nCount) lpi^<LQ@l  
{ jv_z%`  
nSplitter = nCount; Rf9;jwU  
} m:_'r"o  
} K*NCIIDh  
s"gNHp.oF  
A 0~uv4MC  
/* g ]%sX6T  
**Utility.java .EpcMXT%  
*/ mO%F {'  
package NetFox; qy|[V   
FX}kH]  
V $Y=JK@  
public class Utility { rlV:% k  
rY yB"|  
Vz[tgb]-  
public Utility() X+dLk(jI`u  
{ 1g<jr.  
% s&l^&ux  
N/CL?Z>c  
} ny'?Hl'Q  
J'4Pp<  
//线程睡眠 \k&2nYVHf  
public static void sleep(int nSecond) \2]M &n GT  
{ qD!qSM  
try{ ,E ]vM&  
Thread.sleep(nSecond); O1xK\ogv  
} W w\M3Q`h  
catch(Exception e) RKru hF  
{ :k&R]bc9  
e.printStackTrace (); 5\S s`#g  
} ^6g^ Q*"  
} }Y9= 3X  
d%?$UnQ  
//日志 v%^"N_]  
public static void log(String sMsg) dA 03,s  
{ lW6$v* s9  
System.err.println(sMsg); xfegi$  
} EnW}>XN  
,r_%p<lOFu  
?/3'j(Gk  
public static void log(int sMsg) ^W#161&  
{ Z/G`8|A  
System.err.println(sMsg); 8=kIN-l_  
} #X 1 GL  
} X?f\j"v  
\P~ h0zg?  
\%BII>VS  
/* }o,-@R~  
**TestMethod.java \k 9EimT}  
*/ e2F{}N  
package NetFox; b';oFUU>Q  
~$PY6s  
8@rddk  
public class TestMethod { Ar{7H)V:  
@y1:=["b  
u7(<YSOs  
public TestMethod() -}x( MZ  
{ ///xx/weblogic60b2_win.exe GUDz>(  
try{ lD9QS ;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 0Ba*"/U]t~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); oU`{6 ~;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 2p|ed=ly%  
fileFetch.start(); `En>o~L;  
} ^7l+ Of b3  
catch(Exception e){e.printStackTrace ();} z ?L]5m` H  
}ebu@)r  
" rVf{  
} 4"^v]&I  
}j`#s  
_<^mi!Y  
public static void main(String[] args) JfLoGl;p m  
{ T;C0t9Yew  
new TestMethod(); 'f_[(o+n  
} 8{4SaT.-Rm  
} P1G;JK  
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