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http断点续传简单实现(java)

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/*  :tZsSK  
**SiteFileFetch.java Tr?p/9.m  
*/ >>{):r Z  
package NetFox;  R[m-jUL  
import java.io.*; ?^~ZsOd8B  
import java.net.*; PlB3"{}0Q  
*O$|,EsY  
-- %XkO  
public class SiteFileFetch extends Thread { XCI  
D|5mNX %e  
] 0R*F30]  
SiteInfoBean siteInfoBean = null; //文件信息Bean Y!M0JSaM  
long[] nStartPos; //开始位置 I7U/={[J  
long[] nEndPos; //结束位置 3 P0z$jh"H  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \ aJ>?   
long nFileLength; //文件长度 Pn9".  
boolean bFirst = true; //是否第一次取文件 Vo"G@W)lZ  
boolean bStop = false; //停止标志 "e-Y?_S7R8  
File tmpFile; //文件下载的临时信息 `<tRfl}qs  
DataOutputStream output; //输出到文件的输出流 fn<dr(Dx  
JzEg`Sn^  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) E{V?[HcWq  
public SiteFileFetch(SiteInfoBean bean) throws IOException :P-H8*n""  
{ iFUiw&  
siteInfoBean = bean; iM8Cw/DS  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); }Cu:BD.zQ  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); OmB M)g  
if(tmpFile.exists ()) q_[y|ETJ]  
{ YIk@{V  
bFirst = false; #K^hKx9  
read_nPos(); ft/k-64  
} \IQG%L{  
else Uc!k)o#=  
{ tpS gbGzp  
nStartPos = new long[bean.getNSplitter()]; 9Buss+K?/h  
nEndPos = new long[bean.getNSplitter()]; ]2-Qj)mZ]  
} 5 SQ!^1R 9  
0gqV>:  
RZxh"lIo  
a?W5~?\9  
} ;SXkPs3q  
+^9^)Ur|  
BQfnoF  
public void run() )Cdw_Yx  
{ uT]$R  
//获得文件长度 c%5P|R~g]p  
//分割文件 f_ MK4  
//实例FileSplitterFetch q#j[0,^ $  
//启动FileSplitterFetch线程 ?sHZeWZ(  
//等待子线程返回 J;>;K6pW  
try{ q!W,2xqZoq  
if(bFirst) gbMA-r:IC  
{ al#(<4sJ  
nFileLength = getFileSize(); ?J$k 5;  
if(nFileLength == -1) #_ulmB;  
{ 1V`-D8-?  
System.err.println("File Length is not known!"); mZU L}[xf  
} LHtO|Utn(  
else if(nFileLength == -2) ddL3wQ  
{ ;X+0,K3c  
System.err.println("File is not access!"); >C,0}lj  
} =RUy4+0>F  
else 6`2i'flv  
{ FqJd  
for(int i=0;i<nStartPos.length;i++) qVU<jt  
{ O\7x+^.  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Q7u|^Gu,5  
} #c:@oe4v  
for(int i=0;i<nEndPos.length-1;i++) =H7p&DhD[  
{ Y1lUO[F j  
nEndPos = nStartPos[i+1]; \X %#-y  
} Sck!w 3  
nEndPos[nEndPos.length-1] = nFileLength; 'R1C-U3w,  
} kt Z~r. +  
} [ DpOI  
C+\z$/q  
MY{Kq;FvRP  
//启动子线程 A23K!a2u&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; \@PMj"p|:  
for(int i=0;i<nStartPos.length;i++) i$pUUK  
{ X,3"4 SK  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YAR$6&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ExS&fUn `C  
nStartPos,nEndPos,i); P [aE3Felk  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); '[6]W)f  
fileSplitterFetch.start(); :&5u)  
} BUZ74  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [e,xC!2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \u.5 _ g  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >? o5AdZ  
nEndPos = " + nFileLength); ;PVE= z+y  
// fileSplitterFetch[nPos.length-1].start(); yVzV]&k  
&H+ wzx<  
R[F`b  
//等待子线程结束 H5]q*D2  
//int count = 0; .+2:~%v6  
//是否结束while循环 4grV2xtX  
boolean breakWhile = false; %^W(sB$b  
\aSc2Ml]3n  
&7kLSb&|;  
while(!bStop) bZSt<cH3  
{ =?L16mu1&  
write_nPos(); =WN8> <K!  
Utility.sleep(500); $o9^b Z  
breakWhile = true; oTk\r$4eb  
f`vWCb  
n<EIu  
for(int i=0;i<nStartPos.length;i++) Af]BR_-  
{  l  
if(!fileSplitterFetch.bDownOver) "/O07l1Q<  
{ {uwPP2YD,  
breakWhile = false; gT[]"ZT7  
break; )cgNf]oy  
} (| O(BxS  
} Dg^s$2  
if(breakWhile) + d>2'  
break;  k=t{o  
wR 2`*.O  
1_&W1o  
//count++; O|m-[]  
//if(count>4) IF&edP[V  
// siteStop(); -= c&K&  
} S]E|a@kD3  
R(> oyxA[F  
5 3+C;]J  
System.err.println("文件下载结束!"); Hj-n 'XZ  
} y[f%0*\B  
catch(Exception e){e.printStackTrace ();} U&^(%W#  
} @0:Eg1-  
[C ezz5  
U0|wC,7"  
//获得文件长度 <_8eOL<X  
public long getFileSize() M$v\7vBgO!  
{ Ai%Wt-  
int nFileLength = -1; ! .Pbbs%  
try{ n%2c<@p#  
URL url = new URL(siteInfoBean.getSSiteURL()); *` -  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ye^#]%m  
httpConnection.setRequestProperty("User-Agent","NetFox"); Yh,,(V6  
aEUEy:.  
).Z U0fV  
int responseCode=httpConnection.getResponseCode(); f U<<GK70  
if(responseCode>=400) i @M^l`w  
{ 0kp{`3ce  
processErrorCode(responseCode); " u]X/ {L  
return -2; //-2 represent access is error 3DjX0Dx/l  
} f#38QP-T  
<@>icDFEHn  
gBgaVG  
String sHeader; ?MRT  
rJ4A9d3:  
!y1qd  
for(int i=1;;i++) Ux);~P`/o  
{ w$qdV,s 7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); u~t%GIg  
//Utility.log(in.readLine()); [*vR&4mk  
sHeader=httpConnection.getHeaderFieldKey(i); M&(0n?R"R  
if(sHeader!=null) 7 A{R0@  
{ 'cN3Vv k  
if(sHeader.equals("Content-Length")) 9$sx+=(  
{ [2!?pVI  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 06af{FXsGb  
break; G`v(4`tA  
} uMFV^&ZF  
} 9j5k=IXg#a  
else Y>i Qp/k:  
break; 1N.weey}W  
} LqQ&4I  
} 6 #jpA.;  
catch(IOException e){e.printStackTrace ();} cW{Bsr   
catch(Exception e){e.printStackTrace ();} sVS),9\}  
a{I(Qh!}  
(K kqyrb  
Utility.log(nFileLength); s|Vbc@t  
Y0Rk:Njc  
aH$DEs  
return nFileLength; e&pt[W}X%u  
} HvG~bZN  
,7Q b24A  
mj& 4FQ#O*  
//保存下载信息(文件指针位置) Wh?3vZ^  
private void write_nPos() T ^`R  
{ yEL5U{  
try{ @vi;P ^1!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); t] G hONN  
output.writeInt(nStartPos.length); bmRp)CYd  
for(int i=0;i<nStartPos.length;i++) XJ1<!tl  
{ Vg`32nRN  
// output.writeLong(nPos); > 8!9  
output.writeLong(fileSplitterFetch.nStartPos); a [BIY&/Q  
output.writeLong(fileSplitterFetch.nEndPos); QlnI&o  
} %vWh1-   
output.close(); #"JtH"pF  
} r[&/* ~xL  
catch(IOException e){e.printStackTrace ();} /:w.Zf>B9  
catch(Exception e){e.printStackTrace ();} O=}jg0k  
} C/z0/mk  
h"$], =  
K"=I,Vr:  
//读取保存的下载信息(文件指针位置)  4V 5  
private void read_nPos() -[A=\]RfJ  
{ @3Mp>u/  
try{ <QRRD*\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); JW=P} h  
int nCount = input.readInt(); oe1$;K>.7  
nStartPos = new long[nCount]; \4hB1-  
nEndPos = new long[nCount]; =@ed {~  
for(int i=0;i<nStartPos.length;i++) $@ZrGT  
{ Cbr>\;sc2Z  
nStartPos = input.readLong(); '_M"yg6d  
nEndPos = input.readLong(); :&=`xAX-  
} k 3 oR:  
input.close(); ;LFs.Jc<  
} 7,D6RP(b  
catch(IOException e){e.printStackTrace ();} >KCnmi  
catch(Exception e){e.printStackTrace ();} FJ V!B&  
} p M_oIH'8:  
-* piC(  
.^FdO$"  
private void processErrorCode(int nErrorCode) oAq<ag\qV  
{ =8 Jq'-da  
System.err.println("Error Code : " + nErrorCode); /HM 0p  
} OYk/K70l3  
uU`Mq8) R  
FP h1}qS  
//停止文件下载 wb (quu  
public void siteStop() k9o LJ<.k  
{ e_t""h4D  
bStop = true; af;~<o a  
for(int i=0;i<nStartPos.length;i++) i{nFk',xX  
fileSplitterFetch.splitterStop(); `Ct fe8  
ood,k{  
rTYMN  
} ^yVKW5x  
} 6n Hyd<o  
//负责部分文件的抓取 -@G,Ry-\t  
**FileSplitterFetch.java `RL n)a  
*/ !:<n]-U  
package NetFox; Hyz:i)2  
+ Awo\;@,  
U=\!`_f':  
import java.io.*; kmF@u@5M  
import java.net.*; (GDW9:  
H6%%n X  
0%GQXiy  
public class FileSplitterFetch extends Thread { f-l(H="e  
}*M>gvPo  
x`gsD3C  
String sURL; //File URL 4^AdSuV  
long nStartPos; //File Snippet Start Position Qj',&b  
long nEndPos; //File Snippet End Position ?LA` v_  
int nThreadID; //Thread's ID jun$C Y4  
boolean bDownOver = false; //Downing is over 5"I8ric  
boolean bStop = false; //Stop identical z!:%Hbh=  
FileAccessI fileAccessI = null; //File Access interface Ny)N  
rIZ^ix-N  
QwgP+ M+  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException "1%YtV5R{  
{ EnnE@BJ"  
this.sURL = sURL; u40<>A  
this.nStartPos = nStart; YO`V'6\  
this.nEndPos = nEnd; ?'r=>'6D  
nThreadID = id; |$a!Zx94^  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 UU" '  
} d{G*1l(X  
We*&\e+"T  
E [b6k&A  
public void run() l5esx#([*R  
{ iF'qaqHWY4  
while(nStartPos < nEndPos && !bStop) !1cVg ls|  
{ tg' 2 v/  
`78)|a*R.  
[5sa1$n96G  
try{ SK G!DKQ  
URL url = new URL(sURL); %Y*]eLT>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); UKBaGX:v  
httpConnection.setRequestProperty("User-Agent","NetFox"); &5o ln@YL  
String sProperty = "bytes="+nStartPos+"-"; LyA}Nd]pyq  
httpConnection.setRequestProperty("RANGE",sProperty); N@r`+(_t  
Utility.log(sProperty); Cp.qL  
pLea 4  
;f+bIYQz  
InputStream input = httpConnection.getInputStream(); Y5?OJO{h"  
//logResponseHead(httpConnection);  El:&  
$ %BNoSK  
EHqcQx`K_  
byte[] b = new byte[1024]; E-J<%+  
int nRead;  pu?D^h9/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^4 ?LQ[t'  
{ N9=1<{Z  
nStartPos += fileAccessI.write(b,0,nRead); kcN#g- 0  
//if(nThreadID == 1) z*B-`i.  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); F>/"If#  
} b'$fr6"O1  
q7u bRak  
 {;| >Qn  
Utility.log("Thread " + nThreadID + " is over!"); )=@ SA`J  
bDownOver = true; S1D=' k]  
//nPos = fileAccessI.write (b,0,nRead); <9jN4hV  
} 1xzOD@=dI  
catch(Exception e){e.printStackTrace ();} Nr#" 5<W  
} 2E*h,Mo  
} }SZU'lYHoM  
c6_i~0W56  
|;k@Zlvc  
//打印回应的头信息 oZSPdk  
public void logResponseHead(HttpURLConnection con) T?Y/0znB*  
{ 95%QF;h  
for(int i=1;;i++) "[t b-$ER  
{ &D*22R4{CX  
String header=con.getHeaderFieldKey(i); ZI/Ia$O  
if(header!=null) oQ"J>`',  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~|5B   
Utility.log(header+" : "+con.getHeaderField(header)); -J\R}9 lIm  
else qVMBZ\`Qm  
break; 5 i;n:&Y  
} L>.* ^]  
} UG:S!w'  
na,i(m?l  
TM2pE/P  
public void splitterStop() %6eQ;Rp*  
{ h1+lVAQbT  
bStop = true; E[kf%\  
} 0` \!O(jJ  
dAkJ5\=*  
6< O|,7=_  
} 0JS#{EDh+  
y|(C L^(  
eB,eu4+-  
/* q6a7o=BP]  
**FileAccess.java t],5{UF  
*//文件访问(定位,写) g6p:1;Evf  
package NetFox; T>qI,BEY  
import java.io.*; +o[- ED  
`@)>5gW&p  
{RPZq2Tpc  
public class FileAccessI implements Serializable{ ZxvBo4>tH  
Kdr7JQYzuz  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Ia!B8$$'RP  
RandomAccessFile oSavedFile; FQW{c3%qZ  
long nPos; AaX][2y8  
kK&M>)&o#  
ll8Zo+-[  
public FileAccessI() throws IOException Tw+V$:$$  
{ nXFPoR)T  
this("",0); (`me}8  
} xq-TT2}<L  
pf[m"t6G~  
S&Szc0-|k  
public FileAccessI(String sName,long nPos) throws IOException Bt[Wh@  
{ lJIcU RI4  
oSavedFile = new RandomAccessFile(sName,"rw"); !Pf6UNN'  
this.nPos = nPos; `y0u(m5  
oSavedFile.seek(nPos); z8-dntkf  
} NL} Q3Vv1.  
}ofx?s}  
L-z9n@=8\  
public synchronized int write(byte[] b,int nStart,int nLen) Gw1Rp  
{ N&jHU+{OU  
int n = -1; w+W! dM  
try{ Cyu= c1D;  
oSavedFile.write(b,nStart,nLen); fv+t%,++:  
n = nLen; {#C)S&o)6  
} 5[5|_H+0  
catch(IOException e) 0LD$"0v/C3  
{ L=#nnj-  
e.printStackTrace (); = iXHu *g  
} wJMk%N~R:  
CD:$22*]  
v{c,>]@  
return n; 3[;fO_R  
} ScCA8JgY  
G%FLt[  
S\"#E:A  
} ]21`x  
x*7Q  
" .<>(bE  
/* s=[T,:Z  
**SiteInfoBean.java ^sqTgrG  
*/ u}Q cyG^  
package NetFox; U"L 7G$  
,:=g}i  
*-\qO.4\  
public class SiteInfoBean { 3$f+3/l  
$rV4JROb  
pr?k~Bn  
private String sSiteURL; //Site's URL ;]\>jC  
private String sFilePath; //Saved File's Path I3,0vnE@  
private String sFileName; //Saved File's Name rm?C_  
private int nSplitter; //Count of Splited Downloading File UVlh7wjg  
%yPjPUHy  
k;V (rf`  
public SiteInfoBean() )1, U~+JFU  
{//nSplitter的缺省值为5 `)WC|=w2  
//default value of nSplitter is 5 M7gb3gw6  
this("","","",5); *F;W 1TF  
} Gr8%%]1!0  
,`,1s 9\&t  
^{ {0ajI9C  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) U ljWBd  
{  "[ #.  
sSiteURL= sURL; x +]ek  
sFilePath = sPath; =Vat2'>+  
sFileName = sName; /mG-g%gE  
this.nSplitter = nSpiltter; u ?7^+z  
G<M9 6V  
u8r<B4k  
} B]#^&89wG)  
GFTOP%Tgl  
8Ao-m38  
public String getSSiteURL() ;q&uk -  
{ U uEm{  
return sSiteURL; FFq8LM8  
} SbXV'&M2AT  
KD^n7+w%  
@fh:lsw  
public void setSSiteURL(String value) 7Q0vwKC8>  
{ w`I+ 4&/h  
sSiteURL = value; A{%LL r:  
} a&Z;$  
Bg.  
Oj8xc!d'  
public String getSFilePath() Dp-j(F  
{ q#PMQR"C  
return sFilePath; X 4CiVV  
} j.kv!;Rj=  
nq qqP  
!S#K6:  
public void setSFilePath(String value) L};P*{q2Z  
{ 3g87ir  
sFilePath = value; a[=;6!  
} 0iI|eE o  
zK>}x=  
'37 <+N  
public String getSFileName() 'OI(MuSn  
{ UK5u"@T  
return sFileName; aNUM F  
} p}p}!M|  
Vl/fkd,Z  
3FG'A[x3O  
public void setSFileName(String value) hdDL92JVg  
{ )(+q~KA}  
sFileName = value; _sAcvKH  
} sL], @z8<k  
{RN-rF3w  
sB0m^Y'  
public int getNSplitter() JH._/I  
{ 3}5Ya\x  
return nSplitter; }CM#jN?(  
} /HVxZ2bar  
dlH&8  
N{H#j6QW  
public void setNSplitter(int nCount) Yy0U2N [i  
{ t1ers> h  
nSplitter = nCount; *X uIA-9  
}  PckAL  
} NtNCt;_R7  
d)kOW!5\  
^B$cfs@*  
/* M^{=&  
**Utility.java n(#[[k9&Ic  
*/ {~`{bnx^]7  
package NetFox; >02p,W6S>  
yp]z@SYA@  
J"K(nKXO_?  
public class Utility { U>0bgL  
w[g`)8Ib  
e)$a;6  
public Utility() _wUg+Xs]  
{ K0|:+s@u  
Ctbc!<@o  
:A+}fB IN  
} "a-;?S&  
#giH`|#d  
//线程睡眠 pP%9MSCi  
public static void sleep(int nSecond) 7c83g2|%   
{ F_@?'#m  
try{ vi]cl=S  
Thread.sleep(nSecond); 63QF1*gPH  
} Q@[(0R1  
catch(Exception e) U~w8yMxX  
{ O-ppR7edh  
e.printStackTrace (); oG\lejO  
} <B!DwMk;.  
} NH4T*R)Vz  
1[!7xA0j  
//日志 :OV6R ,  
public static void log(String sMsg) [Pl''[  
{ B & ]GGy  
System.err.println(sMsg); n7.85p@ua  
} f^lhdZ\  
q+ `QiPj  
qW S"I+o,S  
public static void log(int sMsg) : . PRM+  
{ [WI'oy  
System.err.println(sMsg); Bh7hF?c Sj  
} ccT <UIpq  
} wli H3vA_  
/4;Sxx-  
ji<(}d~L*  
/* :mhO/Bx  
**TestMethod.java N]-skz<v  
*/ >z7 3uKA(  
package NetFox; R&Ss ET.  
, [<$X{9  
thz[h5C?C  
public class TestMethod { m#<Jr:-  
Kw(S<~9-@  
e/x6{~ju^N  
public TestMethod() @sUec  
{ ///xx/weblogic60b2_win.exe v6ei47-  
try{ n<1*cL:8B  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Rm`P.;%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TW}].A_-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^fE8|/]nG9  
fileFetch.start(); IY|`$sHb  
} `VF_rC[?  
catch(Exception e){e.printStackTrace ();} yb,$UT"]  
WM7LCP  
Tj}%G  
} [=cYsW%WG  
Awr(}){  
@"H7Q1Hg!*  
public static void main(String[] args) g_rk_4]  
{ (\nEU! Y  
new TestMethod(); OI kjO}/7  
} K"ly\$F  
} @>&b&uj7T  
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