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http断点续传简单实现(java)

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/* d+/d)cu  
**SiteFileFetch.java 2Ay2 G-  
*/ 79i>@u%  
package NetFox; l5aQDkp}  
import java.io.*; 9zX\i oT  
import java.net.*; 7qs[t7-h?  
8sL7p4  
F35e/YfG  
public class SiteFileFetch extends Thread { \tQRyj\|  
'vh:(-  
v!W,h2:J  
SiteInfoBean siteInfoBean = null; //文件信息Bean )`L!eN  
long[] nStartPos; //开始位置  Z3I<  
long[] nEndPos; //结束位置 &3AGj,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 k6dSj>F>  
long nFileLength; //文件长度 }+u<^7$g|  
boolean bFirst = true; //是否第一次取文件 j| 257D  
boolean bStop = false; //停止标志 Lrz>00(*4  
File tmpFile; //文件下载的临时信息 DTJ~.  
DataOutputStream output; //输出到文件的输出流 wD*_S}]  
aE:fMDS|x  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) &gq\e^0CRZ  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1W; +hXx  
{ T,;6q!s=  
siteInfoBean = bean; inp=-  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); a1s=t_wT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ne;,TJ\  
if(tmpFile.exists ()) Qs~;?BH&  
{ T6{IuQjXs  
bFirst = false; K}Aaflq  
read_nPos(); (=7e~'DC  
} ZZ4W?);;  
else cnI!}Bu  
{ _7 n+j  
nStartPos = new long[bean.getNSplitter()]; \b' <q  
nEndPos = new long[bean.getNSplitter()]; bZ0r/f,n$  
} c.NAUe_3  
.lqo>Ta y  
rJR"[TTJ  
n#m )]YQC  
} b`1P%OjC  
h v9s  
cA_v*`YL  
public void run() Yj;$hV8j(  
{ cz.-cuD[iD  
//获得文件长度 @1rF9< 4g  
//分割文件 {Rbc  
//实例FileSplitterFetch Ll&Y_Ry  
//启动FileSplitterFetch线程 <~f/T]E,  
//等待子线程返回 2<<,aL*  
try{ GT* \gZ  
if(bFirst) .\i9}ye  
{ / EWF0XV!  
nFileLength = getFileSize(); #O G_O I  
if(nFileLength == -1) 1!,lI?j,  
{ Ib]{rmaP  
System.err.println("File Length is not known!"); 84|Hn|4t  
}  x@Q}sW92  
else if(nFileLength == -2) qc@CV:  
{ sgFpZk  
System.err.println("File is not access!"); E@t^IGD r  
} ij%\ld9kd  
else MB:E/  
{ 0hCJovSG%  
for(int i=0;i<nStartPos.length;i++) `y m^0x8  
{ CkIICx  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); KeY)%{  
} LkNC8V  
for(int i=0;i<nEndPos.length-1;i++) $Nnz |y  
{ %  &{>oEQ  
nEndPos = nStartPos[i+1]; trg+" )a  
} YQ2ie>C8  
nEndPos[nEndPos.length-1] = nFileLength; YS/{q~$t  
} =XyK/$  
} fMd]P:B  
nB"q  
C$Ldz=d  
//启动子线程 91`biVZfA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |fq1Mn8  
for(int i=0;i<nStartPos.length;i++) N!aV~\E  
{ F5:4 B]ZF  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &QLCij5:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), hG; NJx-=R  
nStartPos,nEndPos,i); NSj}?hz  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g,mcxXO  
fileSplitterFetch.start(); wbVM'E/&  
} (lT H EiX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :,6dW?mun6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); bvs0y7M='  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,??xW{* |  
nEndPos = " + nFileLength); r(0I>|u  
// fileSplitterFetch[nPos.length-1].start(); i$$\}2m{L  
>\[sNCkf  
qFt%{~a S  
//等待子线程结束 nSmYa7  
//int count = 0; t k2B\}6  
//是否结束while循环 H+\rCefba  
boolean breakWhile = false; d8/lEmv[  
SO3WOR`3  
hPP+lqY[  
while(!bStop) 8&f}GdZh  
{ +u:8#!X$RD  
write_nPos(); 'l)@MX bGL  
Utility.sleep(500); ?}bSQ)b  
breakWhile = true; WUMx:a0!  
x]J{EA{+  
XBdC/DM[  
for(int i=0;i<nStartPos.length;i++) No!P?  
{ y2o?a6`  
if(!fileSplitterFetch.bDownOver) {FteQ@(  
{ tbl!{Qwx  
breakWhile = false; 6t<~. 2'  
break; Ilsh Jo  
} `yNNpSdS1  
} )d_)CuUBe  
if(breakWhile) &> p2N  
break; +);o{wfW  
) yRC$7I  
&X9#{:l=  
//count++; V :*GG+4  
//if(count>4) ?20y6c<  
// siteStop(); _T<ney}Y<  
} >5i1M^g(  
SG$/v  
kT[]^Jtc  
System.err.println("文件下载结束!"); &7XB $  
} yI h>j.P  
catch(Exception e){e.printStackTrace ();} 0+m"eGwTm  
} (<=qW_iW  
lD _  u  
'w^1re= R  
//获得文件长度 {M$mrmG  
public long getFileSize() !f V.#9AB#  
{ *(& J^  
int nFileLength = -1; &H-39;?u  
try{ :DR G=-M  
URL url = new URL(siteInfoBean.getSSiteURL()); ^4`q%_vm  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); EAqTXB@XU  
httpConnection.setRequestProperty("User-Agent","NetFox"); sbQmPV  
RT F9;]Ti  
P)tXU  
int responseCode=httpConnection.getResponseCode(); U"<Z^)  
if(responseCode>=400) 72@8M  
{ \Llrs-0 M  
processErrorCode(responseCode); gPd:>$  
return -2; //-2 represent access is error hJrxb<9@Y0  
} P5%DvZB$w  
\"<&8  
P (_:8|E  
String sHeader; f)vD2_E  
(IAl$IP63s  
h,\^Sb5AP  
for(int i=1;;i++) pIqPIuy  
{ VQ$=F8ivG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); mdoy1a  
//Utility.log(in.readLine()); D-8%lGS  
sHeader=httpConnection.getHeaderFieldKey(i); 0 jVuF l  
if(sHeader!=null) &YmOXKf7  
{ eWhv X9 <  
if(sHeader.equals("Content-Length")) !3-mPG< ]  
{ Cc1sZWvz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Z=L' [6  
break; 49@ pA-  
} UFyGp>/06  
} _r+9S.z  
else v}M, M&?  
break; G$x uHHZ'  
}  i('z~  
} }^pnwo9vV  
catch(IOException e){e.printStackTrace ();} _( 0!bUs>  
catch(Exception e){e.printStackTrace ();} O (tcu@vfl  
q(\$-Dk.Vv  
fp:j~a>E  
Utility.log(nFileLength); '_4u, \SG  
IhJ _Yed  
v7\~OOoH]  
return nFileLength; 3Nsb@0  
} Ni(D[?mZ  
@j9yc  
Z@RAdwjR`p  
//保存下载信息(文件指针位置) SdYES5aES  
private void write_nPos() :{E3H3  
{ Vj:)w<] ,  
try{ 7Aq4YjbX  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #D .H2'_}  
output.writeInt(nStartPos.length); <T+Pw7X   
for(int i=0;i<nStartPos.length;i++) Yc"G="XP;  
{ __-rP  
// output.writeLong(nPos); qV@xEgW#r  
output.writeLong(fileSplitterFetch.nStartPos); F'C]OMBE  
output.writeLong(fileSplitterFetch.nEndPos); +G7A.d`V}  
} g5M-Vu  
output.close(); |2 g }i\  
} Ipb 4{A&"\  
catch(IOException e){e.printStackTrace ();} U :J~O y_Z  
catch(Exception e){e.printStackTrace ();} 7 G~MqnO|  
} !:c7I@  
"sUe:F;  
yV$p(+KkS  
//读取保存的下载信息(文件指针位置) qusgX;)  
private void read_nPos() n?YGX W/  
{ ]Q6,,/nn  
try{ c42p>}P[  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); JLT':e~PX  
int nCount = input.readInt(); 4Q z  
nStartPos = new long[nCount]; bO9F rEz5  
nEndPos = new long[nCount]; R 7xV{o  
for(int i=0;i<nStartPos.length;i++) f]J?-ks  
{ c)rI[P7Q  
nStartPos = input.readLong(); kFw3'OZ,  
nEndPos = input.readLong(); {1#5\t>9yD  
} 9cQKXh:R.  
input.close(); <Zl0$~B:5  
} oQjh?vm  
catch(IOException e){e.printStackTrace ();} v)%EG  
catch(Exception e){e.printStackTrace ();} $qP9EZ]JC  
} s,]6Lri`\  
nC_<pq^tr  
jQ%}e"  
private void processErrorCode(int nErrorCode) ! r.X.C  
{ b3#c0GL  
System.err.println("Error Code : " + nErrorCode); :>F:G%(DK  
} w^A8ZT0^7  
|jEKUTv,G  
yXg783B|v  
//停止文件下载 yJ/m21f  
public void siteStop() (x&#>5  
{ 3543[W#a  
bStop = true; {pd%I  
for(int i=0;i<nStartPos.length;i++) pZlBpGQf  
fileSplitterFetch.splitterStop(); %vxd($Ti"  
zc*qmb  
P]yER9'  
} a_x$I? ,  
} I]~xs0$4#  
//负责部分文件的抓取 rv9qF |2r{  
**FileSplitterFetch.java qWw@6VvoQ  
*/ "h2;65@  
package NetFox; }{bO ~L7  
PcM:0(,G  
>^+Q`"SN  
import java.io.*; r1}7Q7-z  
import java.net.*; u32wS$*8  
44kY[jhf  
lY?TF  
public class FileSplitterFetch extends Thread { jMW|B  
87YT;Z;U&  
&EE6<-B-  
String sURL; //File URL 8ENAif   
long nStartPos; //File Snippet Start Position I"Ju3o?u  
long nEndPos; //File Snippet End Position &{Uaa  
int nThreadID; //Thread's ID hy W4=  
boolean bDownOver = false; //Downing is over 4JU#3  
boolean bStop = false; //Stop identical RNl%n}   
FileAccessI fileAccessI = null; //File Access interface 43,- t_jV  
K*7*`6iU  
5\:#-IYJ  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException rouD"cy  
{ nFw&vR/q  
this.sURL = sURL; e%wbUr]c2  
this.nStartPos = nStart; [EB2o.E sO  
this.nEndPos = nEnd; o'>jO.|  
nThreadID = id; <2}"Y(zwKl  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &X}9D)\UJ  
} ] A<\ d  
14s+ &  
B,e@v2jO|  
public void run() j(va# f#  
{ ;6fkG/T  
while(nStartPos < nEndPos && !bStop) SY>N-fW\H:  
{ je_77G(F  
nUd(@@%m  
=1VY/sv  
try{ 1?E\2t&K  
URL url = new URL(sURL); hYb!RRGn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /bt@HFL|`  
httpConnection.setRequestProperty("User-Agent","NetFox"); %QwMB`x  
String sProperty = "bytes="+nStartPos+"-"; @B7 ;  
httpConnection.setRequestProperty("RANGE",sProperty); _ky!4^B  
Utility.log(sProperty); !%T@DT=l&  
&b"PjtU.X  
&|/C*2A  
InputStream input = httpConnection.getInputStream(); IL YS:c58=  
//logResponseHead(httpConnection); T{?!sB3  
:_)Xe*O  
zT!JHG  
byte[] b = new byte[1024]; H{p+gj^J  
int nRead; 8QFY:.h&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 4&$hBn=!  
{ >]ZojdOl)  
nStartPos += fileAccessI.write(b,0,nRead); ^~=o?VtBg  
//if(nThreadID == 1) `.L8<-]W  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 4)v\Dc/9i  
} N<$ uAns  
UCvMW*gs  
wQPjo!FEX  
Utility.log("Thread " + nThreadID + " is over!"); *AZC{jP  
bDownOver = true; bL swq  
//nPos = fileAccessI.write (b,0,nRead); 34s:|w6y  
} vlEd=H,LT  
catch(Exception e){e.printStackTrace ();} Vu~mi%UH  
} AL H^tV?  
} { F. Ihw  
.'__ [|-{;  
pOnZ7(  
//打印回应的头信息 >jN)9}3>-#  
public void logResponseHead(HttpURLConnection con) Vwm\a]s  
{ )Je iTh^  
for(int i=1;;i++) M ;\K+,  
{ *Z)`:Gae  
String header=con.getHeaderFieldKey(i); _F,@mQ$!  
if(header!=null) 7F)HAbIS  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); h %MPppCEa  
Utility.log(header+" : "+con.getHeaderField(header)); ?>4^e:  
else .$99/2[90  
break; !. q*bY  
} s7a\L=#p(  
} DX4 95<6*  
= 1`  
OM}:1He  
public void splitterStop() <Ni]\-*  
{ }{j[  
bStop = true; 47ir QK*  
} eR8h4M~O  
MFE~bU(h  
)7c^@I;7  
} 6M612   
?w3f;v  
z'fGHiX7.0  
/* XK(<N<Z@|e  
**FileAccess.java ew }C*4qH  
*//文件访问(定位,写) .hETqE`E  
package NetFox; 3<'SnP3mY  
import java.io.*; KY2xKco  
!{Y$5)Xh`]  
7CrWsQl u  
public class FileAccessI implements Serializable{ 33"{"2==`  
;rd!kFd#bq  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 s {$c8  
RandomAccessFile oSavedFile; @kI^6(.  
long nPos; Jw;J$ u!d  
i1|-  
ffuV$#  
public FileAccessI() throws IOException lEQn2+  
{ V 1#/ +~  
this("",0); t=A| K    
} W c-P= J*m  
mP3:Fc _G  
bLaD1rnGi  
public FileAccessI(String sName,long nPos) throws IOException l3l[jDa,2  
{ [dOPOA/d  
oSavedFile = new RandomAccessFile(sName,"rw"); F4">go  
this.nPos = nPos; Wm Od1  
oSavedFile.seek(nPos); |D`Zi>lv  
} y5+-_x,  
Ww)qBsi8  
QJGRi  
public synchronized int write(byte[] b,int nStart,int nLen) _y5b>+  
{ %DzS~5$G  
int n = -1; ]7'Q2OU7  
try{ }ndH|,  
oSavedFile.write(b,nStart,nLen); 3#0nus|=S  
n = nLen; PJh\U1Z  
} uop_bJ  
catch(IOException e) j0:F E  
{ ~mmI] pC  
e.printStackTrace (); 0+cRUH9Ew  
} 4.CLTy3W  
GD~3RnGQ{  
hMi!H.EX.  
return n; f-4<W0%  
} ad i5h  
s~M!yuH  
t2tH%%Rs  
} |$7!u DU8  
-D{~7&  
`^ F'af  
/* >.J68 x  
**SiteInfoBean.java <[l2]"Q  
*/ M*aE)D '  
package NetFox; VY~WkSi[<  
1sn!!  
v_)cp9d]  
public class SiteInfoBean { 6mMJ$FY+  
t(Iy[-  
!>9*$E |  
private String sSiteURL; //Site's URL *"j_3vAx  
private String sFilePath; //Saved File's Path G0y%_"[  
private String sFileName; //Saved File's Name B^$l]cvZ  
private int nSplitter; //Count of Splited Downloading File ?#slg8[  
jVk|(  
^x:4%%Q]l  
public SiteInfoBean() B]Yj"LM)  
{//nSplitter的缺省值为5 o.}^6.h"  
//default value of nSplitter is 5 &&JI$x0;  
this("","","",5); <fs2;  
} klJDYFX=HK  
] p'+F  
M}/%t1^g:  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) EzzzH(!j  
{ 3)42EM'9(  
sSiteURL= sURL; -^\k+4;  
sFilePath = sPath; p~Dm3^Y  
sFileName = sName; UxD1+\N6?  
this.nSplitter = nSpiltter; sOU_j4M{  
R0*DfJS:Z  
uTB; Bva  
} otX#}} +  
"Z}0A/y  
#;}IHAR  
public String getSSiteURL() V/>SjUNq  
{ POUB{ba  
return sSiteURL; ^D oJ='&  
} BFj@Z'7P  
Yg2z=&p-{"  
.B#Lt,m  
public void setSSiteURL(String value) "%A[%7LY  
{ Z2*hQ`eE  
sSiteURL = value; wrGd40  
} ?R"5 .3  
J,m.LpY  
/x-Ja[kL  
public String getSFilePath() UkXc7D^jwm  
{ ><`.(Z5c  
return sFilePath; R%3H"FU9w  
} |W*f 6F3  
!!Mp;h'}-  
#8nF8J< 4  
public void setSFilePath(String value) 9OT2yC T  
{ &\C vrxa  
sFilePath = value; Zb);08X  
} i&.F}bEi  
4B (*{  
K%Q^2"Eb0  
public String getSFileName() t#Yyo$9  
{ iVXR=A\er  
return sFileName; WMh'<'w N_  
} 0Xk;X1Xl  
>+,1@R  
R&PQ[Xc  
public void setSFileName(String value) a7#Eyw^H{  
{ Hvor{o5|tB  
sFileName = value; \ov>?5  
} Wc`Vcn1  
|a\s}M1  
3%|<U51  
public int getNSplitter() l\$_t2U  
{ \Xxx5:qM  
return nSplitter; FopD/D{  
} <w{W1*R9  
q. BqOa:  
yFJ(b%7  
public void setNSplitter(int nCount) [k."R@?  
{ t*.v!   
nSplitter = nCount; )2rI/=R  
} :peBQ{bj  
} &[RC4^;\V  
fjp>FVv3  
vkbB~gr@*  
/* ;;l(  
**Utility.java .=^h@C*   
*/ Mh3zl  
package NetFox; B(^fM!_%-6  
(T'inNbJe  
@&E E/j^  
public class Utility { 3]} W  
66Hu<3X P  
>|z=-hqPK  
public Utility() #/1A:ig  
{ | G%MiYd  
dF1Bo  
OQ!mL3f  
} Hyee#fB  
1egryp  
//线程睡眠 -P'>~W,~  
public static void sleep(int nSecond) cJE2z2uW0  
{ `5GJ,*{z  
try{ uLL#(bhDr  
Thread.sleep(nSecond); Tb{,WUJg2  
} UbQeN  
catch(Exception e) WWE?U-o  
{ vO4 &ZQ>6  
e.printStackTrace (); 3_Oq4/  
} n]8_]0{qi  
} +;; fw |/  
EidIi"sr  
//日志 DlIfr6F  
public static void log(String sMsg) Pu axS  
{ T<!`~#kM  
System.err.println(sMsg); )(DV~1r=  
} dHOz;4_  
Ii[rM/sG  
MgtyO3GUAD  
public static void log(int sMsg) &V$'{  
{ v8pUt\m"  
System.err.println(sMsg); jl:O~UL6i  
} /9GqEQsfM  
} c+4SGWmO  
+m>Kb edl  
GD< Afni  
/* $L`7(0U-  
**TestMethod.java bWMM[pnL  
*/ typ*.j[q  
package NetFox; R^8Opf_UN  
< W&~tVv  
2 ] 4R`[#  
public class TestMethod { Po^2+s(fY  
zlFl{t  
Bq:@ [pCQ  
public TestMethod() OWq~BZ{  
{ ///xx/weblogic60b2_win.exe w;#9 hW&  
try{ 7Uj[0Awn  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); -,5g cD  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); L<Lu;KnY6  
SiteFileFetch fileFetch = new SiteFileFetch(bean); rxDule3m  
fileFetch.start(); 0U$6TDtmE  
} &ul9N)A  
catch(Exception e){e.printStackTrace ();} gNZ^TeT  
1p8E!c{}j  
}#yRa Ip  
} ;W+.]_$6)T  
]pB~&0jg  
*><] [|Y@H  
public static void main(String[] args) PK+][.6H  
{ 9:=a FP  
new TestMethod(); y>~Ke UC  
} /6S/a*`<X  
} n+!.0d}6  
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