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http断点续传简单实现(java)

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/* 4i0~t~vDpr  
**SiteFileFetch.java S*;8z}5<\  
*/ \.h!'nfF  
package NetFox; Xv ;} !z  
import java.io.*; sYnf #'  
import java.net.*; >DX\^86x  
q\wT[W31@  
?K, xxH  
public class SiteFileFetch extends Thread { 0>hV?A  
$1<V'b[E  
*Y !'3|T  
SiteInfoBean siteInfoBean = null; //文件信息Bean N8a+X|3]0  
long[] nStartPos; //开始位置 VZ"W_U,  
long[] nEndPos; //结束位置 eytd@-7uX  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 UHr0J jQK  
long nFileLength; //文件长度 ,iKEIxA!  
boolean bFirst = true; //是否第一次取文件 *m2{6N_  
boolean bStop = false; //停止标志 [/_M!&zz2  
File tmpFile; //文件下载的临时信息 rPaUDR4U  
DataOutputStream output; //输出到文件的输出流 9W{`$30  
F-i`GMWC  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类)  c(Liwuj  
public SiteFileFetch(SiteInfoBean bean) throws IOException g+>$_s  
{ t(3<w)r2  
siteInfoBean = bean; ,<iJ#$: Sx  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); E?%SOU<  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7/*Q?ic  
if(tmpFile.exists ()) T=lir%q  
{ AIZs^ `_  
bFirst = false; 'iy &%?  
read_nPos(); f-6hcd@Ca  
} kmHIU}Z  
else E/x2LYH  
{ EC[2rROn\  
nStartPos = new long[bean.getNSplitter()]; uJ:'<dJ  
nEndPos = new long[bean.getNSplitter()]; r![RRa^  
} i4 BCm/h  
76e%&ZG)Q  
Q'?{_  
1rs`|iX5  
} U)IW6)q  
?-"xP'#  
lwS6"2q  
public void run() E]z Td$v6  
{ ^`0^|u=  
//获得文件长度 >T'=4n['  
//分割文件 );4lM%]eb  
//实例FileSplitterFetch q ld2<W  
//启动FileSplitterFetch线程 i3C5"\y  
//等待子线程返回 $nR1AOm}.B  
try{ h\+U+ ?u  
if(bFirst) QWt ?` h=  
{ B8Ob~?  
nFileLength = getFileSize(); f{ZOH<"Lo  
if(nFileLength == -1) :?1r.n  
{ wps`2`z  
System.err.println("File Length is not known!"); c.5?Q >!+  
} XXuIWIhm  
else if(nFileLength == -2) sT| $@$bN  
{ {XC1B  
System.err.println("File is not access!"); 3GEI)!  
} {d`e9^Z:  
else S+c)  
{ ~udi=J |  
for(int i=0;i<nStartPos.length;i++) b"U{@  
{ ')pXQ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); unE h  
} i:ar{ q  
for(int i=0;i<nEndPos.length-1;i++) :W'Yt9v)  
{ J23Tst#s  
nEndPos = nStartPos[i+1]; >;@ _TAF  
} bn`1JI@S4  
nEndPos[nEndPos.length-1] = nFileLength; D&5>Op4U  
} 1mT3$Z  
} F,2)Udim  
C'bW3la  
YGp8./ma<I  
//启动子线程 Uloa]X=Im8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; //C3tW  
for(int i=0;i<nStartPos.length;i++) Wj2s+L7,  
{ F@e9Dz|  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I@ dS/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), nic7RN?F<  
nStartPos,nEndPos,i); ka_]s:>+  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); gXtyl]K:  
fileSplitterFetch.start(); Q+e|;Mj  
} plL##?<D<  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RS&l68[6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g'G"`)~ 2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?-^eI!  
nEndPos = " + nFileLength); FJ}RT*7_C  
// fileSplitterFetch[nPos.length-1].start(); sQt]Y&_/@  
b&k !DeE  
&A=>x  
//等待子线程结束 i7h!,vaK  
//int count = 0; 6FMW}*6<  
//是否结束while循环 x!CCSM;q  
boolean breakWhile = false; ?yKW^,q+  
_yje"  
Y8I*B =7  
while(!bStop) NABwtx>.  
{ ?C#=Q6  
write_nPos(); _jmkAmeu  
Utility.sleep(500); ?m3,e&pB5  
breakWhile = true; xA|72!zk0P  
Fl,(KST z  
c}9.Or`?  
for(int i=0;i<nStartPos.length;i++) YGVj$\  
{ NP%Y\%;l6  
if(!fileSplitterFetch.bDownOver) |G.|ocj;  
{ BElVkb  
breakWhile = false; CB(Qy9C%h[  
break; 02Z># AE  
} 2/.E uf   
} n6T@A;_g  
if(breakWhile) iU^KmM I  
break; DgOO\  
h+o-h4X  
s53 Pw>f  
//count++; h WvQh  
//if(count>4) `usX(snY  
// siteStop(); 1#H=<iJ  
} *QAcp` ;*  
,v;P@RL|g  
6 /8?:  
System.err.println("文件下载结束!"); E? > ERO3  
} W7 9wz\a  
catch(Exception e){e.printStackTrace ();} 7hPiPv  
} > %5<fK2  
+o]DT7W  
-3 .Sr|t  
//获得文件长度 -eH5s3:A  
public long getFileSize() \W5fcxf  
{ .Y}~2n  
int nFileLength = -1; *g =ey?1S  
try{ 0pT?qsM2  
URL url = new URL(siteInfoBean.getSSiteURL()); ^J,Zl`N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Kj| l]'  
httpConnection.setRequestProperty("User-Agent","NetFox"); g9 .b6}w!  
OQt_nb#z`{  
'0z-duu  
int responseCode=httpConnection.getResponseCode(); P !:LAb(  
if(responseCode>=400) xij`Mr  
{ =FXO1UZ!  
processErrorCode(responseCode); =b{wzx}e  
return -2; //-2 represent access is error P@ Oq'y[  
} i v7^ !  
ay}} v7)GM  
=<ngtN  
String sHeader; x9UF  
+Tnn'^4  
Gh3b*O_,  
for(int i=1;;i++) d>j`|(\  
{ :q_(=EA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); eH.~c3o  
//Utility.log(in.readLine()); 9sQ7wlK  
sHeader=httpConnection.getHeaderFieldKey(i); {DzOXTI[Y  
if(sHeader!=null) BeAkG_uG  
{ y7ng/vqM7  
if(sHeader.equals("Content-Length")) ZzZy2.7  
{ `9IG//  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N?]HWP^pg  
break;  4[=vt  
} e nsou!l  
} ,,_$r7H`  
else r+6=b"  
break; B%P g:|  
} I<p- o/TP  
} Z(F`M;1>xI  
catch(IOException e){e.printStackTrace ();} JHN{vB  
catch(Exception e){e.printStackTrace ();} XcfvmlBoD-  
8G&'ED_&  
nksx|i l  
Utility.log(nFileLength); {OA2';3  
~\;s}Fv.  
JDi\?m d.  
return nFileLength; L\1&$|?  
} u-yVc*<,  
R(jp  
b^WTX  
//保存下载信息(文件指针位置) Bf {h\>q  
private void write_nPos() q~QB?+ x&  
{ xaQO=[  
try{ 0E[&:6#Y  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3aL8GMiu  
output.writeInt(nStartPos.length); >)E{Hs  
for(int i=0;i<nStartPos.length;i++) Npq_1L  
{ Aj9<4N  
// output.writeLong(nPos); KxZup\\:v  
output.writeLong(fileSplitterFetch.nStartPos); hzG+s#  
output.writeLong(fileSplitterFetch.nEndPos); >NL4&MV:  
} $\:;N]Cs~0  
output.close(); N@Fof(T&  
} CKoRq|QG_  
catch(IOException e){e.printStackTrace ();} L[M`LZpJo  
catch(Exception e){e.printStackTrace ();}  R d|#-7  
} KmUH([#  
2y"]rUS`  
;8!L*uMI  
//读取保存的下载信息(文件指针位置) (yh zjN~  
private void read_nPos() g9N_s,3jC  
{ oT=XCa5  
try{ x6-bAf  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ~!bA<q  
int nCount = input.readInt(); :PJ 5~7C  
nStartPos = new long[nCount]; a#Yo^"*1  
nEndPos = new long[nCount]; 1?6zsA%N  
for(int i=0;i<nStartPos.length;i++) &w4~0J>v!  
{ bq+ Q$#F2X  
nStartPos = input.readLong(); V 4~`yT?*"  
nEndPos = input.readLong(); gaBVD*>  
} .(D,CGtYb  
input.close(); S3cV^CzNg  
} HN7C+e4U~  
catch(IOException e){e.printStackTrace ();} X:3W9`s )*  
catch(Exception e){e.printStackTrace ();} >ZX&2 {  
} 2h:*lV^  
WoYXXYP/E  
>)V1aLu=  
private void processErrorCode(int nErrorCode) aJAQ G  
{ sr|afqjXD  
System.err.println("Error Code : " + nErrorCode); 2D`_!OG=  
} j,:vK  
B)^uGS W  
-pb>=@Yq  
//停止文件下载 )I/K-zj  
public void siteStop() \%=GM J^[p  
{ y5oC|v7  
bStop = true; B<et&r;  
for(int i=0;i<nStartPos.length;i++) $7\!  
fileSplitterFetch.splitterStop(); |3ob1/)p0  
*3A`7usU  
BH@b]bEJ  
} Hu4\4x$?  
} oQsls9t  
//负责部分文件的抓取 'h]sq {  
**FileSplitterFetch.java at(oepq  
*/ ;s$bVGHr  
package NetFox; 9/LnO'&-  
-FxE!K  
JZc"4qf@OT  
import java.io.*; R:[IH2F s  
import java.net.*; KUR9vo  
-c_}^j  
xzI?'?duC  
public class FileSplitterFetch extends Thread { klUW_d-  
_T8o]  
dE ,NG)MH  
String sURL; //File URL VZ o,AP~  
long nStartPos; //File Snippet Start Position U/p|X)  
long nEndPos; //File Snippet End Position ke~S[bL%-  
int nThreadID; //Thread's ID # Vq"Cf  
boolean bDownOver = false; //Downing is over o?T01t=  
boolean bStop = false; //Stop identical z8 n=\xL  
FileAccessI fileAccessI = null; //File Access interface E;*JD x  
4/_@F>I_  
M2{AaYgD  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]&oQ6  
{ DrY5Q&S  
this.sURL = sURL; 2%i3[N*  
this.nStartPos = nStart; ,o?yS>L_r  
this.nEndPos = nEnd; =x QLf4>  
nThreadID = id; \R}`S`fIw`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 rhr(uCp/  
} v \xuq`  
x!@3.$  
B#Q=Fo 6  
public void run() Lt<KRs  
{ XFS"~{  
while(nStartPos < nEndPos && !bStop) <E&[sQ|3  
{ ~WKcO&  
94Hs.S)  
"{1SDbwmMo  
try{ $t1XoL  
URL url = new URL(sURL); Z` ;.62S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6Z:swgi6&  
httpConnection.setRequestProperty("User-Agent","NetFox"); ue/GB+U  
String sProperty = "bytes="+nStartPos+"-"; $$GmundqB  
httpConnection.setRequestProperty("RANGE",sProperty); ` 6'dhB  
Utility.log(sProperty); 0P%,1M3d  
|o5F%1o  
VK~ OL  
InputStream input = httpConnection.getInputStream(); "&@v[O)!xu  
//logResponseHead(httpConnection); &OXnZT3P  
)9PP3"I  
eG F{.]  
byte[] b = new byte[1024]; 0}:wM':G  
int nRead; |K7zN\ Wq  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }BR@vY'd  
{ bAd$ >DI[  
nStartPos += fileAccessI.write(b,0,nRead);  Ie<`WU K  
//if(nThreadID == 1) p%?VW  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /&T"w,D  
} kr=&x)Wy!  
4!3mSWNV  
|IgH0 zZ  
Utility.log("Thread " + nThreadID + " is over!"); l+V#`S*q  
bDownOver = true; h^`!kp  
//nPos = fileAccessI.write (b,0,nRead); R, J(]ew  
} doj$chy  
catch(Exception e){e.printStackTrace ();} >axf_k  
} Qgel^"t]i  
} X-mhz3Q&a  
piy_9nk  
;FI"N@z  
//打印回应的头信息 kCuIEv@  
public void logResponseHead(HttpURLConnection con) <z2*T \B!8  
{ # $dk  
for(int i=1;;i++) FK:Tni  
{ \{Yi7V Xv  
String header=con.getHeaderFieldKey(i); .dr-I7&!  
if(header!=null) "j]85  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); QE b ^'y  
Utility.log(header+" : "+con.getHeaderField(header)); O0i)Iu(J7;  
else FFvF4]|L  
break; QL{^  
} B0&W wa:  
} /Ayo78Pi  
>E:V7Fa  
Af V a[{E  
public void splitterStop() Pv>W`/*_,s  
{ $QbaPmHW  
bStop = true; zdh&,!] F6  
} "F.0(<4)  
YR\pt8(z?  
$v#\bqY  
} VEtdp*ot  
:I)WSXP9h  
jH4'jB  
/* B7R*g,(  
**FileAccess.java Alh"ZT^*  
*//文件访问(定位,写) "'8^OZR  
package NetFox; [*jvvkAp  
import java.io.*; %`F &,!d  
N-~Uu6zr  
Te:4 z@?  
public class FileAccessI implements Serializable{ k|-P&g  
: K#z~#n  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C'a%piX  
RandomAccessFile oSavedFile; p3N/"t&>  
long nPos; 6')pM&`t  
XLeQxp=  
L+rMBa  
public FileAccessI() throws IOException Z WVN(U  
{ gFx2\QV  
this("",0); ;YYo^9Lh}  
} )uJu.foE  
O`pqS\H  
T/b%,!N)  
public FileAccessI(String sName,long nPos) throws IOException Z%t"~r0PS  
{ D^Cpgha  
oSavedFile = new RandomAccessFile(sName,"rw"); "G+g(?N]j  
this.nPos = nPos; wVw?UN*rm;  
oSavedFile.seek(nPos); \TF='@u.  
} X`n)]~  
v"po}K  
Ew9\Y R}  
public synchronized int write(byte[] b,int nStart,int nLen) y7?n;3U]CS  
{ ioZ{2kK  
int n = -1; YKk*QcAn  
try{ VPAi[<FzOG  
oSavedFile.write(b,nStart,nLen); eMDO;q  
n = nLen; 5ml#/kE  
} YaWZOuxm  
catch(IOException e) ST *\Q  
{ #KOr-Yg|U  
e.printStackTrace (); LZ ?z5U:  
} *G6Py,- !f  
)fRZ}7k:  
`o;E  
return n; vfn _Nq;  
} _3_kvs  
L T.u<ThR}  
LrL ZlJf  
} C1V@\mRi  
_(R1En1  
p#yq'kY  
/* L93PDp4v  
**SiteInfoBean.java "Q>gQKgL  
*/ LxcC5/@\~(  
package NetFox; VD,p<u{r  
5Q9nJC{'NN  
Tf|?j=f  
public class SiteInfoBean { V^  
Xqz\%&G  
R[%ZyQ_  
private String sSiteURL; //Site's URL Ep.Q&(D >  
private String sFilePath; //Saved File's Path ~eVq Fc  
private String sFileName; //Saved File's Name %+=y!  
private int nSplitter; //Count of Splited Downloading File D>U b)i  
$P{|^ou3a#  
=.sg$VX  
public SiteInfoBean() 2%|0c\y|z=  
{//nSplitter的缺省值为5 mHiV};$  
//default value of nSplitter is 5 S1!X;PP/  
this("","","",5); D<DSK~  
} ^~iFG+g5  
tz).]E D  
8c6dTT4  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) qir/Sa' [  
{ $CXMeY{tOo  
sSiteURL= sURL; `[&) X  
sFilePath = sPath; 5f` a7R  
sFileName = sName; GmONhh(k  
this.nSplitter = nSpiltter; #DqVh!t"  
+J`HI1  
npj_i /&g  
} x3`b5^  
 wh A  
EGY'a*]cU  
public String getSSiteURL() G~ldU: ?  
{ 0# )I :5  
return sSiteURL; N 9.$--X}D  
} ? bq S{KF  
-Tzp;o  
g?}$"=B   
public void setSSiteURL(String value) g}vOp3 ^  
{ 4F-r}Fj3  
sSiteURL = value; n)n>|w_  
} ?tf/#5t}  
em@bxyMm  
ZSBa+3;z  
public String getSFilePath() w6-A-M6hD  
{ iPD5 KsAOA  
return sFilePath; B;3lF ;3`  
} a/n KKhXaM  
1feZ`P ;  
+5zLQ>]z  
public void setSFilePath(String value) &EELq"5K  
{ Nx%]dOa  
sFilePath = value; 8Moe8X#3  
} }k`-n32)|  
9i&(VzY[=  
3!&PI  
public String getSFileName() /uh?F  
{ rzR=% >  
return sFileName; xD:t$~  
} dTE(+M- Gr  
4P>[]~S  
g}cb>'=={  
public void setSFileName(String value) k^JV37;bl  
{ ??'>kQ4  
sFileName = value; v>p UVM  
} e%Sw(=a  
oCCTRLb02  
gB&8TE~Y  
public int getNSplitter() (O&R-5m  
{ '=M4 (h  
return nSplitter; jHU5>Gt-}  
} )&nfV5@"  
b3h3$kIYN  
fP:n=A{  
public void setNSplitter(int nCount) dGNg[  
{ H}nPaw]G  
nSplitter = nCount; H*gX90{!2  
} ]12ypcf  
} >Q`\|m}x)Q  
K5h2 ~  
2 SJ N;A~}  
/* XBmAD!  
**Utility.java -$x5[6bN  
*/ + YjK#  
package NetFox; T3JM8  
C:?mOM#_  
"-WEUz  
public class Utility { -MCDX^ >P  
 .# Jusd  
1-h"1UN2E  
public Utility() eB]R<a60  
{ ]"*sp  
bg =<)s  
k|r+/gIV  
} MYmH?A  
(59u<F  
//线程睡眠 ;b-d2R  
public static void sleep(int nSecond) kT=KxS{  
{ "u H VX|`  
try{ wqZ*$M   
Thread.sleep(nSecond); [yEH!7  
} ri]"a?Rm  
catch(Exception e) d:_3V rRZ  
{ G2,9$8qE  
e.printStackTrace (); /}ADV2sF  
} o)M=; !  
} kf Xg\6uKc  
}(yX$ 3?`  
//日志 ^@4$O|3Wh'  
public static void log(String sMsg) G<M X94?  
{ ,P T5-9 m  
System.err.println(sMsg); v)!C Dpw  
} $3BH82  
[%1 87dz:D  
hE9UWa.Q>  
public static void log(int sMsg) G'dN_6ho3  
{ T+q3]&  
System.err.println(sMsg); E[nJ'h<h  
} :mI[fQ  
} 'A#bBn,|  
fPj*qi  
Ibbpy++d[  
/* n;w&} g  
**TestMethod.java ,5 A&  
*/ 50?5xSEM0_  
package NetFox; o=}vK[0u  
$.g)%#h:  
,Qw\w,  
public class TestMethod { >~vZ+YO  
`+c8;p'q  
`;R [*7  
public TestMethod() WNa#X]*E)  
{ ///xx/weblogic60b2_win.exe (U GmbRf&  
try{ p&O-]o8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); g:&V9~FR  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); XVRtfo  
SiteFileFetch fileFetch = new SiteFileFetch(bean); aP}%&{iC*  
fileFetch.start(); F,NS:mE  
} pRTdP/(OQ  
catch(Exception e){e.printStackTrace ();} F VVpyB|  
LL}b]B[  
M,WC+")Z=  
} {-'S#04  
4pw:O^v  
.%3qzOrN  
public static void main(String[] args) M?FbBJ`sF  
{ -AX[vTB  
new TestMethod(); ja Ot"iU.B  
} $(PWN6{\r^  
} zB@@Gs>  
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