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http断点续传简单实现(java)

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/* Z{BK@Q4z  
**SiteFileFetch.java |'1.a jxw  
*/ ,*U-o}{8C?  
package NetFox; Y,v9o  
import java.io.*; %hN>o)  
import java.net.*; \1gAWUt('  
wW p7N  
:d9GkC  
public class SiteFileFetch extends Thread { K<:%ofB"S  
sZCK?  
|f @A-d X  
SiteInfoBean siteInfoBean = null; //文件信息Bean LwRzzgt  
long[] nStartPos; //开始位置 }=)u_q  
long[] nEndPos; //结束位置 8^+|I,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 G-2~$ u  
long nFileLength; //文件长度 ;$6L_C4B  
boolean bFirst = true; //是否第一次取文件 iB(?}SaAZ  
boolean bStop = false; //停止标志 j@(S7=^C6%  
File tmpFile; //文件下载的临时信息 v~Dobk/n  
DataOutputStream output; //输出到文件的输出流 A r~/KRK  
:AFW=e@<  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) EBW*v '  
public SiteFileFetch(SiteInfoBean bean) throws IOException "lu^  
{ ]:D&kTc  
siteInfoBean = bean; C(v'7H{4cW  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6Aqv*<1=62  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Qc-W2%  
if(tmpFile.exists ()) 9) ]`le  
{ Y\_mq d  
bFirst = false; S+[,\>pY  
read_nPos(); M !"Q7>d  
} XchD3p+uB  
else hfLe<,  
{ `Zo5!"'  
nStartPos = new long[bean.getNSplitter()]; /<LjD  
nEndPos = new long[bean.getNSplitter()]; &$CyT6mb^  
} aC1 xt(  
-u%o);B  
CPNV\qCY  
hlV(jz  
} |tI{MztJ"c  
k7*-v/ *S  
6zU0 8z0-  
public void run() ;:[P/eg  
{ T<7}IH$6xE  
//获得文件长度 4IfkYM  
//分割文件 /rD9)  
//实例FileSplitterFetch OI)k0t^;D  
//启动FileSplitterFetch线程 `O3#/1+  
//等待子线程返回 sOWP0x  Y  
try{ !lEV^SQJs  
if(bFirst) b4$.uLY  
{ v8E:64  
nFileLength = getFileSize(); ]A-LgDsS  
if(nFileLength == -1) 4xs>X7  
{ UVi9}zr  
System.err.println("File Length is not known!"); u_ :gqvC=  
} e'npa*.e  
else if(nFileLength == -2) 8[^b8^  
{ T[},6I|!  
System.err.println("File is not access!"); ZyC[w 7$I2  
} O>X!78]#K  
else d<\X)-"  
{ x51p'bNy  
for(int i=0;i<nStartPos.length;i++) ^JIs:\ g<<  
{ }FV_jJ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); @&G %cW(  
} S,+|A)\#  
for(int i=0;i<nEndPos.length-1;i++) \3U.;}0_X  
{ kbz+6LcV  
nEndPos = nStartPos[i+1]; y>UQm|o<W  
} %tkL<e  
nEndPos[nEndPos.length-1] = nFileLength; uZ1G,9  
} p_g8d&]V  
} fk5pPm|MiL  
`$;%%/tx  
G\f:H%[5[  
//启动子线程 M|z4Dy  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +>mU4Fwp  
for(int i=0;i<nStartPos.length;i++) a! x?Apww  
{ kafj?F  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [DSzhi]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), W6 *5e{  
nStartPos,nEndPos,i); ",E$}= ,Z  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^j_t{h)W(0  
fileSplitterFetch.start(); /LCRi  
} MIAC'_<-e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )!`>Q|]}Zd  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /Q9iO&Vu  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", G`jJKiC  
nEndPos = " + nFileLength); [*=UH* :'N  
// fileSplitterFetch[nPos.length-1].start(); c$%I^f}'  
9;pD0h|  
%Zu+=I Z  
//等待子线程结束 'F8:|g  
//int count = 0; za4:Jdr  
//是否结束while循环 6$$ku  
boolean breakWhile = false; <m?/yRE K2  
r?n3v[B  
#J c)v0_  
while(!bStop) s\1c.  
{ ivl_=  
write_nPos(); `>}e 5  
Utility.sleep(500); Nj4^G ~_  
breakWhile = true; 5l(NX  
_/[(&}M  
}W R?n  
for(int i=0;i<nStartPos.length;i++) >9]i#So^  
{ 4^BHJOvs  
if(!fileSplitterFetch.bDownOver) +D+Rf,D  
{ SE!0f&  
breakWhile = false; `zRm "G  
break; {f)"F;]V  
} y 4jelg  
} 0j|JyS:}G  
if(breakWhile) ?qjlWCV|e  
break; DWRq \`P  
gkDlh{  
0V:PRq;v0  
//count++; L9)nRV8  
//if(count>4) u~^d5["T  
// siteStop(); 09u@-  
} |d8x55dk  
iPPW_Q9x  
9AdA|/WV  
System.err.println("文件下载结束!"); | sio:QP  
} ep2#a#&'  
catch(Exception e){e.printStackTrace ();} u CNi&.  
} T"$yh2tSY  
<U() *0  
ta 66AEc9  
//获得文件长度 hzjEO2  
public long getFileSize() Lk|%2XGO&  
{ <);Nc1  
int nFileLength = -1; x:)8+Rn}  
try{ *^&2L,w  
URL url = new URL(siteInfoBean.getSSiteURL()); ,2YkQ/ >  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^/kn#1H7&  
httpConnection.setRequestProperty("User-Agent","NetFox"); B@W`AD1^{  
)!&7XL[  
pkL&j<{  
int responseCode=httpConnection.getResponseCode(); IPhV|7  
if(responseCode>=400) hs"=>(P)  
{ *h>KeIB;  
processErrorCode(responseCode); }QL 2#R  
return -2; //-2 represent access is error }t[?g)"M#-  
} }G#TYF}  
czV][\5  
Kf$%C"  
String sHeader; 1 f;k)x  
jCMr[ G=  
?m?DAd~ZY  
for(int i=1;;i++) =hO0 @w  
{ B9RB/vHH  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =;9*gDfD  
//Utility.log(in.readLine()); KU> $=Rd  
sHeader=httpConnection.getHeaderFieldKey(i); f@%H"8w!  
if(sHeader!=null) E  K)7g~  
{ jQp7TdvLE$  
if(sHeader.equals("Content-Length")) jcWv&u|  
{ D,rF?t>=S  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ^f -?xXPx  
break; u2SnL$A7  
} ,3t('SE  
} hDp -,ag{  
else \)=X=yn2  
break; El~x$X*  
} q89#Ftkt  
} <wt#m`Za  
catch(IOException e){e.printStackTrace ();} xbFoXYqgP  
catch(Exception e){e.printStackTrace ();} ]}_@!F)  
$DmWK_A  
ckXJ9>  
Utility.log(nFileLength); P~V0<$C  
!4 4)=xW  
3McBTa!  
return nFileLength; 30(O]@f~  
} 5TqT`XTzm  
h\k!X/  
Vu DSjh  
//保存下载信息(文件指针位置) ]wg+zOJu]+  
private void write_nPos() l  I&%^>  
{ Ds4n>V,o  
try{ :xitV]1.   
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6% @@~"  
output.writeInt(nStartPos.length); qm-G=EX  
for(int i=0;i<nStartPos.length;i++) ;Ocih<4k  
{ TbqED\5@9w  
// output.writeLong(nPos); 8}3dwr;-  
output.writeLong(fileSplitterFetch.nStartPos); j$h.V#1z  
output.writeLong(fileSplitterFetch.nEndPos); / vI sX3v  
} ?\dY!  
output.close(); +'9l 2DI;  
} HhN;&67~Z  
catch(IOException e){e.printStackTrace ();} | I_,;c  
catch(Exception e){e.printStackTrace ();} =.9L/74@  
} `+[e]dH  
F V8K_xj  
-s`/5kD  
//读取保存的下载信息(文件指针位置) {=W TAgP  
private void read_nPos() ^EGe%Fq*x]  
{ fcd\{1#u  
try{ 7mipj]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 0z@ KkU{Z  
int nCount = input.readInt(); {VBx;A3*I  
nStartPos = new long[nCount]; 1b:3'E.#w  
nEndPos = new long[nCount]; eMk?#&a)  
for(int i=0;i<nStartPos.length;i++) Fp>iwdjFg  
{ iUl5yq  
nStartPos = input.readLong(); C~PrIM?  
nEndPos = input.readLong(); FA-"" ]  
} \ct)/  
input.close(); |~b.rKQt[  
} QiB ^U^f  
catch(IOException e){e.printStackTrace ();} *oAv:8"iY  
catch(Exception e){e.printStackTrace ();} ^vXMX^*  
} 2GNtO!B.  
4.|-?qG  
|7Fe~TC  
private void processErrorCode(int nErrorCode) ?N2/;u>  
{ 4fPbwiK j  
System.err.println("Error Code : " + nErrorCode); KE3/sw0  
} vL"U=Q+/eY  
a+!#cQl  
40}qf}8n t  
//停止文件下载 M>hHTa?W  
public void siteStop() l:v:f@M&  
{ Rg3 Lo ?  
bStop = true; BX :77?9,+  
for(int i=0;i<nStartPos.length;i++) c,%9Fh?(  
fileSplitterFetch.splitterStop(); 1"J\iwN3  
et|QW;*L  
rYUhGmg`  
} 5MsE oLg  
} 7Io]2)V  
//负责部分文件的抓取 Afm GA9  
**FileSplitterFetch.java *sI`+4h[  
*/ 5~Vra@iab:  
package NetFox; smEKQHB  
RUHQ]@d#T  
P?%kV  
import java.io.*; >SO !{  
import java.net.*; T_ ifDQX;  
a1]@&D r  
L}O_1+b  
public class FileSplitterFetch extends Thread { '@1oM1  
%Od?(m"&  
S#+Dfa`8X  
String sURL; //File URL .{+<o  
long nStartPos; //File Snippet Start Position <4,hrx&.  
long nEndPos; //File Snippet End Position l \~w(8g<A  
int nThreadID; //Thread's ID ~\A(xmW}  
boolean bDownOver = false; //Downing is over c>+l3&`  
boolean bStop = false; //Stop identical p9w<|ZQ]:  
FileAccessI fileAccessI = null; //File Access interface (S/f!Dk&3  
P,y*H_@k  
o33 wePx,  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException _@I<H\^  
{ S]3K5Z|  
this.sURL = sURL; TJS/O~=  
this.nStartPos = nStart; _l$V|  
this.nEndPos = nEnd; @]r,cPx0Y  
nThreadID = id; 6t9Q,+nJ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位  QDCu  
} "~~Js~  
` #Qlr+X  
5~&9/ ALk5  
public void run() FncK#hZ.  
{ >`Xikn(  
while(nStartPos < nEndPos && !bStop) J})G l  
{ MY>mP  
uan%j]|q%  
1} 1.5[4d  
try{ '0QrM,B9  
URL url = new URL(sURL); e1$T%?(&[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V 8`o71p  
httpConnection.setRequestProperty("User-Agent","NetFox"); ^ NZq1c  
String sProperty = "bytes="+nStartPos+"-"; vmW > $P  
httpConnection.setRequestProperty("RANGE",sProperty); AD_RU_a9  
Utility.log(sProperty); 0mcZe5RS  
y[M<x5  
ziUEA>m */  
InputStream input = httpConnection.getInputStream(); ktlI(#\%  
//logResponseHead(httpConnection); d:08@~#  
N!R>L{H>  
\;&WF1d`ac  
byte[] b = new byte[1024]; V$U#'G>m  
int nRead; {%g]Ym=  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) z ((Y\vP  
{ ^P30g2gv>  
nStartPos += fileAccessI.write(b,0,nRead); +T]/4"^M  
//if(nThreadID == 1) Nl~'W  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J1P jMb}  
} ^0oOiZs  
P)7:G?OTx  
[D/q  
Utility.log("Thread " + nThreadID + " is over!"); (jj=CLe  
bDownOver = true; vjNP  
//nPos = fileAccessI.write (b,0,nRead); ]w7wwU^^*U  
} pC=kvve  
catch(Exception e){e.printStackTrace ();}  ! @EZ  
} Er@'X0n  
} < cNJrer  
7$"{&T  
2G=prS`s  
//打印回应的头信息 ,x (?7ZW>  
public void logResponseHead(HttpURLConnection con) p./9^S  
{ e`]x?t<U4/  
for(int i=1;;i++) l Vb{bO9-O  
{ 2c)Ez?  
String header=con.getHeaderFieldKey(i); {|!> {  
if(header!=null) Epo/}y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); z89!\Q  
Utility.log(header+" : "+con.getHeaderField(header)); o8uak*"{  
else \0)v5u  
break; 4%refqWK  
} VD.wO%9?)  
} :v$][jZ2  
QOT|6)Yb  
E\/J& .  
public void splitterStop() K9\r2w'T'  
{ +f){x9 :  
bStop = true; TUy 25E  
} C-2{<$2k  
5rX_85]  
a_z1S Z2[  
} AHB_[i'>7  
Iu V7~w  
n{*A<-vL  
/* /#Fz K  
**FileAccess.java c^F@9{I  
*//文件访问(定位,写) m#Y[EPF=|  
package NetFox; WALK@0E  
import java.io.*; 8T523VI  
H`T8ydNXa  
%(}%#-X  
public class FileAccessI implements Serializable{ )\PPIY>iP  
NG+%H1!$_  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 P*!~Z *"  
RandomAccessFile oSavedFile; `ElJL{Rn  
long nPos; KFhnv`a.0  
7W.z8>p  
JTcE{i  
public FileAccessI() throws IOException n!?^:5=s  
{ zq Cr'$  
this("",0); =38c}(  
} XjFaP {  
bbG!Fg=qQ?  
f\u5=!kjN  
public FileAccessI(String sName,long nPos) throws IOException c~)H" n  
{ j V'~>  
oSavedFile = new RandomAccessFile(sName,"rw"); W<\*5oB%H  
this.nPos = nPos; GLiD,QX<  
oSavedFile.seek(nPos); GswV/V+u  
} rCsH 0:l8P  
h[& \ OD,P  
5?HoCz]l  
public synchronized int write(byte[] b,int nStart,int nLen) AVO$R\1YR  
{ .2f0e[J  
int n = -1; S<o\.&J  
try{ ]L;X Aj?  
oSavedFile.write(b,nStart,nLen); 7J|e L yj  
n = nLen; {1}p+dEK  
} um=qT)/D  
catch(IOException e) }&Ul(HR  
{ C<E;f]d  
e.printStackTrace (); 9RQw6rL  
} .B_a3K4'{^  
U&OE*dq  
P~@.(hed  
return n; +"3K)9H  
} dk.VH!uVb  
[ J6q(} f  
(;2]`D [x  
} EViDMp"  
~+anI  
Uq=!>C8  
/* q/dja  
**SiteInfoBean.java lQt* LWd[  
*/ v0W/7?D  
package NetFox; 8gXf4A(N  
GcHZ&m4  
oF=UjA  
public class SiteInfoBean { o]WG8Mo-  
GU]_Z!3  
T UO*w  
private String sSiteURL; //Site's URL ,H:{twc   
private String sFilePath; //Saved File's Path a {4RG(I_  
private String sFileName; //Saved File's Name  $&to(  
private int nSplitter; //Count of Splited Downloading File 4qg] oiT  
!~a1xI~s  
1'YksuYx6f  
public SiteInfoBean() V38v2LI  
{//nSplitter的缺省值为5 #RVN 7-x  
//default value of nSplitter is 5 )jm u*D5N  
this("","","",5); Z)dE#A_X  
} wf/DLAC  
%z5P%F'5   
ZfSAXr "(  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =7 ${bp!  
{ 3PRK.vf  
sSiteURL= sURL; {aYCrk1  
sFilePath = sPath;  &&sCaNb  
sFileName = sName; p<AzpkU,A  
this.nSplitter = nSpiltter; 8~eYN- #W&  
\ 0aa0=  
5d5q0bb  
} |c3Yh,Sv  
 mIkc +X  
JN<IMH  
public String getSSiteURL() hwB>@r2  
{ DgRA\[c  
return sSiteURL; =d`/BDD  
} [;8vO=Z  
g9oY K  
oZ"93]3-  
public void setSSiteURL(String value) mZb[Fi  
{ ?j-;;NNf  
sSiteURL = value; @T 8$/  
} ;O Y*`(Id  
oar`xH$C  
{wyf>L0j  
public String getSFilePath() k=r)kkO)  
{ 6<+8[o  
return sFilePath; {fAj*,pzl  
} Q2 @Ugt$  
*d;D~"E<@  
- |j4u#z  
public void setSFilePath(String value) /ng +IC3  
{ [Csv/  
sFilePath = value; L#X!.  
} >djTJ>dl_u  
E#A}J:  
 t_Rpeav  
public String getSFileName()  LAfv1  
{ KD)+& 69  
return sFileName; X__>r ?oJ  
} _aLml9f W  
oiY&O]}  
FsyM{LT  
public void setSFileName(String value) #pm0T1+jW  
{ \"^.>+  
sFileName = value; j/Rm~!q  
} M,j3z #  
I:9jn"  
}xE}I<M  
public int getNSplitter() HLml:B[F(  
{ _6 ,Tb]  
return nSplitter; >84:1 `  
} 39zwPoN>  
%juR6zB%8  
qe\JO'g#e  
public void setNSplitter(int nCount) aur4Ky> :  
{ [~_()i=Y  
nSplitter = nCount; U`h>[9  
} TaN]{k  
} Z?}yPs Ob  
]E/~PV  
!04zWYHo  
/* _~_E(rTn  
**Utility.java ejuw+@ _  
*/ $<N!2[I L  
package NetFox; ^Td_B03)  
' 3MCb  
(T]<  
public class Utility { }F~4+4B^  
ZC\&n4~7  
M XX:i  
public Utility() 8A3pYW-  
{ }#h>*+Q  
t@(`24  
=Hs[peO*  
} .h;PMY+  
Bh\>2]~@a  
//线程睡眠 ue;o:>G  
public static void sleep(int nSecond) :~1sF_  
{ 'l| e}eti>  
try{ (p FPuV  
Thread.sleep(nSecond); j$z<wR7j0  
} ]$VYzE2e  
catch(Exception e) 1sT%g}w@|  
{ |Qe#[Q7  
e.printStackTrace (); .<Lbv5m  
} ;F;"Uw  
} ;GgW&*|  
Zss `##  
//日志 GWU"zWli]z  
public static void log(String sMsg) fuQb h  
{ 6_s_2cr  
System.err.println(sMsg); PU6Sa-fQ2,  
} Hik :Sqpox  
tL;!!vg#V  
1gTW*vLM\  
public static void log(int sMsg) [= GVK  
{ 2K Um(B.I  
System.err.println(sMsg); ia!b0*<   
} Imi#$bF6  
} mF?GQls`  
k[6xuyY]  
z  DP  
/* >brf7h  
**TestMethod.java oBm^RHTZ  
*/ #ZPU.NNT?  
package NetFox; Y~</vz+H  
^zMME*G  
7h3#5Y  
public class TestMethod { h#o3qY  
H.D1|sU  
/-.i=o]b  
public TestMethod() JMUk=p<\  
{ ///xx/weblogic60b2_win.exe /lC&'hT  
try{ [&Z3+/lR*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ^+ hJ& 9W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :< )"G&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wClX3l>y  
fileFetch.start(); Z=B6fu*  
} :`9hgd/9  
catch(Exception e){e.printStackTrace ();} y}fF<qih'>  
{EoRY/]  
n>_EE w2/  
} -7^A_!.  
?HP54G<{xz  
QJcaOXyMS  
public static void main(String[] args) Y\.d s%G  
{ cmzu @zq  
new TestMethod(); ]kN<N0;\d  
} bN ,>,hj  
} /-#1ys#F=  
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