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http断点续传简单实现(java)

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/* 4F'LBS]=0  
**SiteFileFetch.java a~}OZ&PG  
*/ 1};Stai'  
package NetFox; \&3+D8H>n  
import java.io.*; zP8lN(LA  
import java.net.*; 5x4yyb'  
Id .nu/  
pJ"qu,w  
public class SiteFileFetch extends Thread { M`!H"R7  
ChPmX+.i_  
vMH  
SiteInfoBean siteInfoBean = null; //文件信息Bean Ckuh:bs  
long[] nStartPos; //开始位置 #rfiD%c  
long[] nEndPos; //结束位置 UECK:61Me  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 f+,qNvBY/  
long nFileLength; //文件长度 [!#L6&:a8  
boolean bFirst = true; //是否第一次取文件 w-MCZwCr)  
boolean bStop = false; //停止标志 q"8e a/  
File tmpFile; //文件下载的临时信息 K=h9Ce  
DataOutputStream output; //输出到文件的输出流 /]Md~=yNp  
h2]P]@nW;W  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) xj;H&swo  
public SiteFileFetch(SiteInfoBean bean) throws IOException !ons]^km  
{ MaQqs=  
siteInfoBean = bean; :>f )g  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); @,7GaK\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); FbFPJ !fb  
if(tmpFile.exists ()) 37.S\ gO]  
{ K;H&n1  
bFirst = false; f+)L#>Gl?  
read_nPos(); WO>nIo5Y  
} rcG"o\g@+  
else ,m|h<faZL  
{ 'yEHI  
nStartPos = new long[bean.getNSplitter()]; LYK"(C  
nEndPos = new long[bean.getNSplitter()]; YZ8>OwQz2  
} [<yaXQxl  
P{>!5|k  
>jLY"  
O-hAFKx  
} L\"d  
 |TH\`U  
sBg.u  
public void run() %pL''R9VF  
{ 0znR0%~  
//获得文件长度 .g<DD)`  
//分割文件 z,p~z*4  
//实例FileSplitterFetch 0pd'93C  
//启动FileSplitterFetch线程 3~ {:`[0Q  
//等待子线程返回 p6Gy ,C.  
try{ H40p86@M  
if(bFirst) *P=VFP  
{ HBXOjr<,{  
nFileLength = getFileSize(); v^*K:#<Q!  
if(nFileLength == -1) ;$wVu|&  
{ !?h;wR  
System.err.println("File Length is not known!"); ^k">A:E2  
} #h ]g?*}OJ  
else if(nFileLength == -2) K Z91-  
{ n 0L^e  
System.err.println("File is not access!"); c-6?2\]j@  
} =X:Y,?  
else E*K;H8}s  
{ )F]]m#`  
for(int i=0;i<nStartPos.length;i++) zHRplm+ i  
{ +\ .Lp 5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); jm/`iXnMf  
} `1fY)d^ZS  
for(int i=0;i<nEndPos.length-1;i++) _)m]_eS._  
{ 0 /U{p,r6`  
nEndPos = nStartPos[i+1]; Kis"L(C  
} yWo; a  
nEndPos[nEndPos.length-1] = nFileLength; I1M%J@Cz  
} VjZ|$k  
} `b7t4d*  
Iit; F  
S_UIO.K  
//启动子线程 . 3T3E X|G  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ( ^Nz9{  
for(int i=0;i<nStartPos.length;i++) 5<Nx^D  
{ = m#?neop  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `+:`_4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), &d^m 1  
nStartPos,nEndPos,i); S;#'M![8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =dYqS[kJW  
fileSplitterFetch.start(); k,+0u/I  
} "J_9WUN  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >_T-u<E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); s9DYi~/,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", g*C7 '  
nEndPos = " + nFileLength); tl^9WG  
// fileSplitterFetch[nPos.length-1].start(); }Oq5tC@$G  
r52gn(,  
6mxfLlZ  
//等待子线程结束 00~mOK;1  
//int count = 0; ~V1E0qdAE  
//是否结束while循环 }N6.Uu 5zI  
boolean breakWhile = false; ` 7V]y -  
56kI 5:  
kJT)r6  
while(!bStop) =MDys b&:  
{ ],Do6 @M-  
write_nPos(); P{ lB50  
Utility.sleep(500); sWnLEw  
breakWhile = true; ;+ hH  
v;D~Pa  
K`fuf=  
for(int i=0;i<nStartPos.length;i++) =$JET<(  
{ s R/F"  
if(!fileSplitterFetch.bDownOver) ')<hON44EX  
{ '!~)?C<  
breakWhile = false; 7n<::k\lb  
break; r0% D58  
} *#+An<iT ;  
} z[qDkL  
if(breakWhile) |#R7wnE[k~  
break; ^9:Z7 >Z  
59;KQ  
pB0 \\wR  
//count++; ^WWQI+pk  
//if(count>4) &7tbI5na@  
// siteStop(); vy:Z/1q  
} &E5g3lf  
>7DhTM-A  
5vnrA'BhBU  
System.err.println("文件下载结束!"); 4zFW-yy  
} @?]RBX?a  
catch(Exception e){e.printStackTrace ();} 5 #E`=C%  
} &`2)V;t  
8$Y9ORs4  
$X,D(  
//获得文件长度 (V2fRv  
public long getFileSize() f x+/C8GK  
{ iSs:oH3l  
int nFileLength = -1; ri-b=|h2j  
try{ 1\I}2;  
URL url = new URL(siteInfoBean.getSSiteURL()); q9s=~d7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Jij*x>K>y  
httpConnection.setRequestProperty("User-Agent","NetFox"); T</F 0su|  
6?c7$Y  
p9{mS7R9T  
int responseCode=httpConnection.getResponseCode(); )MTOU47U  
if(responseCode>=400) 89(Q1R ?:  
{ &\*(Q*2N  
processErrorCode(responseCode); d5:c^`  
return -2; //-2 represent access is error IF:;`r@%  
} "oO%`:pb  
v"Es*-{B  
U z>+2m(  
String sHeader; s|r3Gv|G  
^.QzQ1=D  
k~1?VQ+?M  
for(int i=1;;i++) #!+:!_45  
{ 3L}A3de'  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); {&1/V  
//Utility.log(in.readLine()); PB\x3pV!}  
sHeader=httpConnection.getHeaderFieldKey(i); u.xnOcOH!  
if(sHeader!=null) ?m"( S oh  
{ 1#+S+g@#  
if(sHeader.equals("Content-Length")) ^s"R$?;h  
{ -PR N:'T  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r3UUlR/Do  
break; 1/J=uH  
} 9~[Y-cpoi  
} I9ep`X6Y  
else &gx%b*;`L0  
break; ER.}CM6{[  
} k@W1-D?  
} U&p${IcEm  
catch(IOException e){e.printStackTrace ();} nb%6X82Q  
catch(Exception e){e.printStackTrace ();} [MY|T<q  
aAUvlb  
=Jb>x#Y  
Utility.log(nFileLength); %n9aaoD  
RPRBmb940  
Z/+#pWBI!  
return nFileLength; 6(ol1 (U  
} oYH-wQj  
JZyAXm%  
$*fMR,~t&  
//保存下载信息(文件指针位置) l!u_"I8j5  
private void write_nPos() 7hPY_W y  
{ zy }$i?  
try{ sd|).;s}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1p=]hC  
output.writeInt(nStartPos.length); qY!Zt_Be6  
for(int i=0;i<nStartPos.length;i++) eehb1L2(b  
{ 5$C-9  
// output.writeLong(nPos); 11;MN  
output.writeLong(fileSplitterFetch.nStartPos); #AQV(;r7@  
output.writeLong(fileSplitterFetch.nEndPos); A~70  
} $qj2w"'  
output.close(); I b5rqU\  
} E~"y$Fqe  
catch(IOException e){e.printStackTrace ();} o?\?@H  
catch(Exception e){e.printStackTrace ();} / %io+94  
} tY4;F\e2|A  
~Z' ?LV<t  
fI|Nc  
//读取保存的下载信息(文件指针位置) d7bS wL  
private void read_nPos() i=2N;sAl  
{ R4:b{)=O  
try{ 3(80:@|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); f4|rVP|x  
int nCount = input.readInt(); qUb&   
nStartPos = new long[nCount]; t"oeQ*d%  
nEndPos = new long[nCount]; I-l_TpM)  
for(int i=0;i<nStartPos.length;i++) &{t,'[ u  
{ hp|YE'uYT  
nStartPos = input.readLong(); I%KYtv~ `  
nEndPos = input.readLong(); e+fN6v5pU  
} ?%[jR=w  
input.close(); ?4T-@~~*`=  
} ysY*k`5  
catch(IOException e){e.printStackTrace ();} lL0APT;  
catch(Exception e){e.printStackTrace ();} IJcsmNWm  
} \qJXF|z<K  
x7 ,5  
|P?*5xPB  
private void processErrorCode(int nErrorCode) `r 3  
{ .(k|wX[Fu~  
System.err.println("Error Code : " + nErrorCode); %d9uTm;  
} >i?oC^QM  
S3Jo>jXS "  
@`9]F7h5W  
//停止文件下载 (TT}6j  
public void siteStop() .HABNPNg(  
{ +ami?#Sz*;  
bStop = true; "E4a=YH_  
for(int i=0;i<nStartPos.length;i++) [ub e6  
fileSplitterFetch.splitterStop(); KF:78C  
7WzxA=*#  
)zDCu`  
} g *+>H1}  
}  O*P.]d  
//负责部分文件的抓取 $VOF Oc  
**FileSplitterFetch.java xr^LFn)  
*/ 5wU]!bxr  
package NetFox; 8P\Zo8}v  
W ]8 QM1$  
j8:\%|  
import java.io.*; J\=*#*rJ1  
import java.net.*; kvu)y`  
((%? `y  
S)"Jf?  
public class FileSplitterFetch extends Thread { )MT}+ai  
{(Es(Sb}c  
k)TpnH! "  
String sURL; //File URL XfIJ4ZM5  
long nStartPos; //File Snippet Start Position Ar#(psU  
long nEndPos; //File Snippet End Position B/Ws_Kv  
int nThreadID; //Thread's ID b4Ekqas  
boolean bDownOver = false; //Downing is over 6[AL|d DK  
boolean bStop = false; //Stop identical KLk~Y0$:v  
FileAccessI fileAccessI = null; //File Access interface N?`' /e  
!U Ln7\@  
:e+jU5;]3  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <<O$ G7c  
{ *wjrR1#81x  
this.sURL = sURL; w7&A0M  
this.nStartPos = nStart; k$:|-_(w  
this.nEndPos = nEnd; C\hM =%  
nThreadID = id; TIg3` Fon  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B^ }yo65I  
} {R{=+2K!|k  
_Y m2/3!  
v4 E}D  
public void run() j3ls3H&  
{ 0jWVp- y  
while(nStartPos < nEndPos && !bStop) 4E}Yt$|  
{ -m#)B~)  
HTTC TR  
lPAQ3t!,  
try{ SSzIih@u  
URL url = new URL(sURL); :\_ 5oVb  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Qn2&nD%zi  
httpConnection.setRequestProperty("User-Agent","NetFox"); buHJB*?9  
String sProperty = "bytes="+nStartPos+"-"; $3kH~3{]  
httpConnection.setRequestProperty("RANGE",sProperty); 7F~X,Dk_  
Utility.log(sProperty); 9} .z;prz  
es0hm2HT3  
sV*H`N')S  
InputStream input = httpConnection.getInputStream(); wVtwx0|1  
//logResponseHead(httpConnection); )0k53-h&  
}c:M^Ff  
3Tm+g2w2V8  
byte[] b = new byte[1024]; d2L&Z_}  
int nRead; I)HPO,7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 3=V &K-  
{ 'dc#F3  
nStartPos += fileAccessI.write(b,0,nRead); 1Ai^cf:S  
//if(nThreadID == 1)  e]$s t?  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o^wqFX(Y  
} tfWS)y7  
>/6 _ ^  
bW+:C5'  
Utility.log("Thread " + nThreadID + " is over!"); "d}Gp9+$VY  
bDownOver = true; GTxk%   
//nPos = fileAccessI.write (b,0,nRead); )=(kBWM  
} M869MDo  
catch(Exception e){e.printStackTrace ();} G^@5H/)  
} M)(DZ}  
} Z4bNV?OH  
bvOq5Q6  
+ >!;i6|  
//打印回应的头信息 b\,+f n  
public void logResponseHead(HttpURLConnection con) tX~w{|k  
{ /dIzY0<aO  
for(int i=1;;i++) dDGQ`+H9  
{ ]eV8b*d6  
String header=con.getHeaderFieldKey(i); K:WDl;8 (d  
if(header!=null) 62NsJ<#>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); b#o|6HkW  
Utility.log(header+" : "+con.getHeaderField(header)); ]/{)bpu  
else :rP=t ,  
break; Zj Z^_X3  
} iU:cW=W|M\  
} ?\n > AC  
z'7]h TA  
y>ktcuML  
public void splitterStop() )O6>*wq  
{ V]?R>qhgu  
bStop = true; l}P=/#</T  
} 3__-nV  
/zox$p$?h  
EiaW1Cs  
} wdoR%b{M  
qxJ\ye+'*  
dD@(z: 5M\  
/* J9 I:Q<;  
**FileAccess.java *=xr-!MEk  
*//文件访问(定位,写)  _','9|  
package NetFox; *OQ2ucC8j  
import java.io.*; - ! S_ryL  
 f)<6  
Kf-JcBsrT  
public class FileAccessI implements Serializable{ h>bx}$q  
(QiAisE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 O.JN ENZf  
RandomAccessFile oSavedFile; UL9n-M =  
long nPos; ,]/X\t5]D  
TJ*T:?>e  
\^1E4C\":  
public FileAccessI() throws IOException . 'yCw#f  
{ $`'/+x"%  
this("",0); M'l ;:  
} >5 BJ3Hf  
#,v {Ihn  
Z #m+ObHK1  
public FileAccessI(String sName,long nPos) throws IOException .o}v#W+st  
{ wS3'?PRX  
oSavedFile = new RandomAccessFile(sName,"rw"); a09<!0Rp  
this.nPos = nPos; y~HP>~Oh  
oSavedFile.seek(nPos); #Rr%:\*  
} `wU!`\  
XB5DPx  
\.}c9*)  
public synchronized int write(byte[] b,int nStart,int nLen) 9MqGIOQ${j  
{ NyuQMU  
int n = -1; 7>*vI7O0l  
try{ Vf1^4 t  
oSavedFile.write(b,nStart,nLen); EB|}fz  
n = nLen; >`D:-huNeE  
} ?Ss!e$jf  
catch(IOException e) ]J]h#ZHx  
{ {(?4!rh  
e.printStackTrace (); pmYHUj #  
} !Xw5<J3L-  
(C)p9-,  
|sZHUf_  
return n; f|oh.z_R  
} f`66h M[  
)BfAw  
z([</D?  
} mXs; b 2r^  
M rb)  
<QGXy=  
/* _h1mF<\ X^  
**SiteInfoBean.java S$X Sei_q  
*/ _GPl gp:  
package NetFox; kg\ >k2h  
J9S>yLQK  
6D_D';o  
public class SiteInfoBean { o3}3p]S\  
}SCM I4\  
)}O8?d`  
private String sSiteURL; //Site's URL w@fi{H(R  
private String sFilePath; //Saved File's Path (&x['IR  
private String sFileName; //Saved File's Name .6 ?U@2  
private int nSplitter; //Count of Splited Downloading File LjHVJSC  
vY`s'%WV  
Ny)X+2Ae  
public SiteInfoBean() C+&l< fM&  
{//nSplitter的缺省值为5 Eu04e N  
//default value of nSplitter is 5 seeB S/%  
this("","","",5); ~4cC/"q$X  
} {H'Y `+  
o*hF<D$Y  
FHI ;)wn=  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ENY+^7  
{ BTrn0  
sSiteURL= sURL; ,UE83j8D^  
sFilePath = sPath; )dd@\n$6  
sFileName = sName;  %D "I  
this.nSplitter = nSpiltter; a C)!T  
8, >P  
63B?.  
} Aq7osU1B  
0_t!T'jr7  
b>JDH1)  
public String getSSiteURL() qJUK_6|3  
{ NQ2E  
return sSiteURL; D. XvG_  
} $L]lHji  
~61v5@  
~ W]TD@w  
public void setSSiteURL(String value) P7/X|M z  
{ FaJ&GOM,  
sSiteURL = value; 5l*&>C[(i  
} G,w(d@  
Thit  
VY\&8n}e(  
public String getSFilePath() SasJic2M  
{ )53y AyP  
return sFilePath; du^J2m{f  
} 65^9  
_:27]K:  
x-3\Ls[I  
public void setSFilePath(String value) <2qr}K{'A  
{ Hj,A5#|=J  
sFilePath = value; P7~>mm+  
} :9 ^* ^T  
kMd.h[X~  
Q]>.b%s[  
public String getSFileName() 1&Zj  
{ ~&bq0 (  
return sFileName; B^9j@3Ux  
} czd~8WgOa  
u;c?d!E  
h'F=YF$o  
public void setSFileName(String value) | Xy6PN8  
{ 4{`{WI{  
sFileName = value; =rX>.P%Q5  
} #;nYg?d=  
'`KY! ]L  
R~$qo)v  
public int getNSplitter() V~5jfcd  
{ aw42oLk  
return nSplitter; }`~+]9 <   
} ^J;bso`  
BThrO d  
?5 7Sk+  
public void setNSplitter(int nCount) %bfQ$a:  
{ <UQbt N-B\  
nSplitter = nCount; '."ed%=MC  
} 3$9W%3  
} w+CA1q<  
n7-6- #  
<e</m)j  
/* B`J~^+`[*  
**Utility.java {{p7 3 'u  
*/ X}\:_/  
package NetFox; 3/n5#&c\4  
Jze:[MYS  
JFk lUgg  
public class Utility { 9-*uPK]m9  
"LTad`]<Ro  
s!7y  
public Utility() k+pr \d~  
{ p= } Nn(  
65Yv4pNL  
WI-1)1t  
} ?<'}r7D   
#4 pB@_  
//线程睡眠 hQDXlFHT  
public static void sleep(int nSecond) r\V ={p  
{ U\*J9  
try{ AkQ ~k0i}b  
Thread.sleep(nSecond); !d0kV,F:  
} 7O-x<P;  
catch(Exception e) _zi|  
{ WEi2=3dV  
e.printStackTrace (); 0Z{ZO*rK  
} ~FG]wNgS  
} :X (=z;B;N  
G*P#]eO  
//日志 ^3L0w}#  
public static void log(String sMsg) SKsKPqz  
{ ,1o FPa{?  
System.err.println(sMsg); uk<9&{  
} A{D];pE`  
Fy-t T]Q9  
?2Py_gkf  
public static void log(int sMsg) wEvVL  
{ P me^l%M  
System.err.println(sMsg); <B6H. P =  
} @QPz #-  
} M:B=\&.O  
338k?nHxv  
n8ZZ#}Nhg  
/* q'Tf,a  
**TestMethod.java '@k+4y9q?  
*/ X?qK0fS  
package NetFox; +OWX'~fd<  
'kO!^6=4M  
lp%pbx43s  
public class TestMethod { ZeaA%y67U  
~%kkeh\j  
P:MT*ra*,  
public TestMethod() t=W}SH  
{ ///xx/weblogic60b2_win.exe mSl.mi(JiZ  
try{ Trz@~d/[,n  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +}os&[S  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); UhQj Qaa~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); UJ')I`zuI  
fileFetch.start(); A@{PZ   
} PP33i@G  
catch(Exception e){e.printStackTrace ();} @YTaSz$L  
9 X`Sm}i  
fN1-d&T  
} LIF7/$,0  
)W _v:?A9  
68C%B9.b'  
public static void main(String[] args) |"CZT#  
{ 5(Q%XQV*P  
new TestMethod(); y,,dCca  
} PmEsN&YP]  
} 4yA+ h2  
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