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http断点续传简单实现(java)

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/* 8XCT[X  
**SiteFileFetch.java D7IhNWrgj  
*/ X~*/ ~f  
package NetFox; \^cXmyQ<%  
import java.io.*; !(S.7#-r  
import java.net.*; oh:.iL}j  
Nbf >Y  
( s+}l?  
public class SiteFileFetch extends Thread { tI0D{Xrc  
(j%"iQD  
A)#Fyde  
SiteInfoBean siteInfoBean = null; //文件信息Bean eOb)uIF  
long[] nStartPos; //开始位置 P-Gp^JX8  
long[] nEndPos; //结束位置 $|@-u0sv  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ;iN [du  
long nFileLength; //文件长度 IUG}Q7w5  
boolean bFirst = true; //是否第一次取文件 X2 <fS~m  
boolean bStop = false; //停止标志 ;+3@S`2r  
File tmpFile; //文件下载的临时信息 Yi`DRkp]3  
DataOutputStream output; //输出到文件的输出流 do.XMdit  
|*~SR.[`  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Ln4Dq[M  
public SiteFileFetch(SiteInfoBean bean) throws IOException kK&AK2  
{ 1#zD7b~  
siteInfoBean = bean; i\>?b)a>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *mw *z|-^V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); M^n^wz  
if(tmpFile.exists ()) |41~U\  
{ @E> rqI;`  
bFirst = false; +wGvY r  
read_nPos(); ws;|fY  
} n&Q0V.  
else DRVvC~M-,  
{ q:wz!~(>  
nStartPos = new long[bean.getNSplitter()]; (AG((eV  
nEndPos = new long[bean.getNSplitter()]; :@Ml-ZE  
} b. :2x4  
>+%0|6VSb  
H@|m^1  
5z.Y}  
} a3[,3  
Eh *u6K)Z  
\h}sA  
public void run() ?%T]V+40  
{ E]pD p /D  
//获得文件长度 ,W$&OD  
//分割文件 =+4om*  
//实例FileSplitterFetch CE4Kc33OU|  
//启动FileSplitterFetch线程 1_mqPMm  
//等待子线程返回 WuQ;Da0+_F  
try{ |QyZ:`0u  
if(bFirst) FW4#/H  
{ rj29$d?Y9  
nFileLength = getFileSize(); Gl4f:`  
if(nFileLength == -1) ~kI$8oAry  
{ i@=(Y~tD`  
System.err.println("File Length is not known!"); AI$\wp#aw  
} `{ \)Wuw  
else if(nFileLength == -2) &<(&u`S  
{ 'qoaMJxN`  
System.err.println("File is not access!"); <I{Yyl^  
} Rf!$n7& \  
else mW3 IR3 b  
{ Rz<'& Z>;  
for(int i=0;i<nStartPos.length;i++) "!#KQ''R  
{ yi<H }&  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Jb|dpu/e  
} k7nke^,|  
for(int i=0;i<nEndPos.length-1;i++) ?{1& J9H  
{ $L72%T  
nEndPos = nStartPos[i+1]; C5TC@w1*  
} LP>GM=S#"  
nEndPos[nEndPos.length-1] = nFileLength; 4@jX{{^6%  
} Upc_"mkI.  
} q3u:Tpn4%  
k P=~L=cK  
gZL,xX  
//启动子线程 DLoH.Fd  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VP }To  
for(int i=0;i<nStartPos.length;i++) A ? [Wfq|  
{ [n$6 T  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &3 x [0DV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), K*tomy  
nStartPos,nEndPos,i); xE6hE'rh.O  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *3(mNpi{_  
fileSplitterFetch.start(); T?*f}J  
} riSgb=7q9  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), M ~6 $kT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /b."d\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3oPyh $*  
nEndPos = " + nFileLength); `dgZ`#  
// fileSplitterFetch[nPos.length-1].start(); fjqd16{Q  
O]?PC^GGY  
N LSJ D  
//等待子线程结束 x.q"FXu  
//int count = 0; L1MG("R  
//是否结束while循环 3#{Al[jq  
boolean breakWhile = false; XJA];9^  
Z1U@xQj  
rotu#?B  
while(!bStop) CE|rn8MB  
{ aco w  
write_nPos(); YN7JJJ/~T  
Utility.sleep(500); 8)YDUE%VH  
breakWhile = true; E g_ram`\R  
8M7Bw[Q1  
Wfsd$kN6{  
for(int i=0;i<nStartPos.length;i++) |u#7@&N1  
{ d_Z?i#r0l  
if(!fileSplitterFetch.bDownOver) =F46v{la  
{ lB   
breakWhile = false; RVh{wg  
break; \$xj>b;  
} AK&=/[U>  
} lPg?Fk7AP  
if(breakWhile) -o@L"C>   
break;  =tc!"{  
)< p ~  
wAc;{60s]  
//count++; bg^ <e}{<H  
//if(count>4) rw[Ioyr-  
// siteStop(); pzeCdHF  
} JD]uDuE  
a" L9jrVrw  
sY&Z/Y  
System.err.println("文件下载结束!"); G BM8:IG \  
} IJDE{)  
catch(Exception e){e.printStackTrace ();} vU9:` @beu  
} +77B656  
b[~-b  
NJg )S2]7  
//获得文件长度 4-oaq'//BT  
public long getFileSize() x !n8Wx  
{ )Cd.1X8  
int nFileLength = -1; /z: mi  
try{ H'&[kgnQ@  
URL url = new URL(siteInfoBean.getSSiteURL()); /25Ay  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); s133N?  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0xfF  
m"wP]OQH*+  
^p3W}D  
int responseCode=httpConnection.getResponseCode(); . Gb!mG  
if(responseCode>=400) Y;k iU  
{ Yw_!40`  
processErrorCode(responseCode); ^95njE`>t`  
return -2; //-2 represent access is error E[<*Al +N  
} @]Lu"h#u=  
LX#gc.c  
1o?uf,H7O  
String sHeader; ;*WG9Y(W  
>+):eB L  
T@a|*.V  
for(int i=1;;i++) z#2n+hwE  
{  |^"0bu"  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); )T^xDx  
//Utility.log(in.readLine()); i:1 @ vo  
sHeader=httpConnection.getHeaderFieldKey(i); ?@;#|^k9  
if(sHeader!=null) PJ^qE| X  
{ U_WO<uhC  
if(sHeader.equals("Content-Length")) IRTD(7"oyp  
{ ygQe'S{!S\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); pj7v{H+  
break; .aR9ulS  
} z7TyS.z  
} q}W})  
else HEw&'  
break; ~ 7<M6F  
} I+ Y{_yw"f  
} oXU b_/  
catch(IOException e){e.printStackTrace ();} L+}<gQJ(  
catch(Exception e){e.printStackTrace ();} 13+. >  
^!gq_x  
a4pewg'  
Utility.log(nFileLength); /i#";~sO  
uaZHM@D  
5]n\E?V'L  
return nFileLength; U>DCra;  
} uF<?y0t  
KtGbpcS$f  
!;0K=~(Y^  
//保存下载信息(文件指针位置) rR 86D  
private void write_nPos() 1xInU_SPf  
{ cQm4q19  
try{ mi[8O$^iJ  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !s:e  
output.writeInt(nStartPos.length); c=X+uO-  
for(int i=0;i<nStartPos.length;i++) mhB2l/  
{ Xt +9z  
// output.writeLong(nPos); ILqBa:J  
output.writeLong(fileSplitterFetch.nStartPos); (>NZYPw^3  
output.writeLong(fileSplitterFetch.nEndPos); aemi;61T\  
} +}PN+:yV  
output.close(); Je}0KW3G9L  
} @_1cY#!  
catch(IOException e){e.printStackTrace ();} m.<u !MI  
catch(Exception e){e.printStackTrace ();} 7Gy:T47T\@  
} 'u~0rMe4})  
J_?v=dW`  
u1=K#5^  
//读取保存的下载信息(文件指针位置) 7*"Jx}eM  
private void read_nPos() [2h.5.af  
{ MdmN7>  
try{ 8:> V'j  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); X-#&]^d  
int nCount = input.readInt(); SMzq,?-`  
nStartPos = new long[nCount]; m xqY  
nEndPos = new long[nCount]; Hq!|r8@6  
for(int i=0;i<nStartPos.length;i++) *ifz@8C }  
{ [FLR&=.(  
nStartPos = input.readLong(); jFUpf.v2  
nEndPos = input.readLong(); MpBdke$  
} >##Z}auY  
input.close(); D:/q<<|  
} 3&nN;4~Zx6  
catch(IOException e){e.printStackTrace ();} niKfat?  
catch(Exception e){e.printStackTrace ();} N$x&k$w R  
} kw E2V+2  
} `5k^J$x  
tym:C7v%~  
private void processErrorCode(int nErrorCode) ?)186dp  
{ ,[)l>!0\H  
System.err.println("Error Code : " + nErrorCode); ~?FhQd\Q  
} =4l @A>  
)BvMFwQG  
Hf\sF(, (  
//停止文件下载 kguZAO6  
public void siteStop() gu+zfvkcY  
{  6su~SPh  
bStop = true; <fM}Kk  
for(int i=0;i<nStartPos.length;i++) Fm,` ]CO  
fileSplitterFetch.splitterStop(); b $J S|  
@Z2np{X:  
Gx6%Z$2n  
} Od)y4nr3~  
} X%3?sH  
//负责部分文件的抓取 H!&_Tv[  
**FileSplitterFetch.java uYWD.]X;[  
*/ (zsv!U  
package NetFox; oQObr  
O9ps?{g  
m\X\Xp~A  
import java.io.*; J=k=cFUX  
import java.net.*; _+'!l'`  
-Ep#q&\  
E6Z kO/  
public class FileSplitterFetch extends Thread { \2 e^x  
23WrJM!2N  
.7  0  
String sURL; //File URL 8B:y46  
long nStartPos; //File Snippet Start Position &9fQW?Czs  
long nEndPos; //File Snippet End Position ?_i >Kx  
int nThreadID; //Thread's ID doOuc4  
boolean bDownOver = false; //Downing is over *=.~PR6W{  
boolean bStop = false; //Stop identical )*>wa%[-q  
FileAccessI fileAccessI = null; //File Access interface cw{TS  
y<E]; ub  
W(R~K -  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %l!?d`?  
{ { ]_j)R  
this.sURL = sURL; [&PF ;)i  
this.nStartPos = nStart; kM{8zpn  
this.nEndPos = nEnd; #Pp:H/b  
nThreadID = id; Rd5_{F  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 RYjK4xT?Y/  
} }b&lHr'Uw  
eNK[P=-  
OtmDZ.t;`  
public void run() M{{kO@P"9  
{ Z )M "`2Ur  
while(nStartPos < nEndPos && !bStop) kuD$]A Q`&  
{ ,1#? 0q  
LwK]fFtu  
@,TIw[p  
try{ jD6HCIjd'  
URL url = new URL(sURL); Q_|}~4_+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wlJi_)!  
httpConnection.setRequestProperty("User-Agent","NetFox");  }o*A>le  
String sProperty = "bytes="+nStartPos+"-"; )q-NE)  
httpConnection.setRequestProperty("RANGE",sProperty); Syy{ ^Ae}  
Utility.log(sProperty); rZJJ\ , |  
e ,/]]E/o  
Z K+F<}  
InputStream input = httpConnection.getInputStream(); jDpA>{O[  
//logResponseHead(httpConnection); 94BH{9b5  
\&hq$  
z3K$gEve  
byte[] b = new byte[1024]; 3NLn}  
int nRead; g"1V ]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Lo{wTYt:J  
{ ,"(G  
nStartPos += fileAccessI.write(b,0,nRead); )>:~XA|?  
//if(nThreadID == 1) A}(]J!rc  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); A-T-4I  
} _&hM6N  
mi7?t/D1Z  
2c 0;P #ol  
Utility.log("Thread " + nThreadID + " is over!"); 5MaN {*)l  
bDownOver = true; 6/mz., g2  
//nPos = fileAccessI.write (b,0,nRead); ,<t.Iz%  
} fq6Obh=A#  
catch(Exception e){e.printStackTrace ();} KtL?,zi  
} E 6TeZ%g  
} 5 ix*wu`,  
!q\=e@j-i  
S F*C'  
//打印回应的头信息 <v|"eq}  
public void logResponseHead(HttpURLConnection con) ,bl }@0A  
{ ]yf?i350  
for(int i=1;;i++) kk-<+R2  
{ RTcxZ/\" #  
String header=con.getHeaderFieldKey(i); E(4c&  
if(header!=null) P\7*ql`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); FT- .gi0  
Utility.log(header+" : "+con.getHeaderField(header)); )bOfs*S  
else z/ 1$G"  
break; m6ge %  
} |NZi2Bu  
} $:F+Nf 8  
OX]$Xdb2:  
_M%S  
public void splitterStop() ~4{q  
{ "kyCY9) %  
bStop = true; wS*r<zj  
} #XDgvX >  
=#V^t$  
&< BBP n@\  
}  4@  
(w hl1  
`|ie#L(:7/  
/* <#C,66k  
**FileAccess.java <bzzbR[F  
*//文件访问(定位,写) lLTqk\8g  
package NetFox; e c&Y2  
import java.io.*; kL*P 3 0  
#u hUZq  
Ds">eNq  
public class FileAccessI implements Serializable{ kP ]Up&'  
f$xXR$mjf  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 mQ:{>`  
RandomAccessFile oSavedFile; q,,  
long nPos; \0b}Z#'0  
f ,cd=vGj  
P }sr  
public FileAccessI() throws IOException *H QcI-  
{ u1%URen[x  
this("",0); ^9[Q;=R  
} 13X}pnW  
7y'uZAF  
^<CVQ8R7  
public FileAccessI(String sName,long nPos) throws IOException <=*f  
{ Gaix6@X6'  
oSavedFile = new RandomAccessFile(sName,"rw"); 4b2d(x)0X  
this.nPos = nPos; kXSX<b<%  
oSavedFile.seek(nPos); uAn}qrqE9  
} 5daq}hsQs  
@L3XBV2  
T$%|=gq  
public synchronized int write(byte[] b,int nStart,int nLen) p\w<~ pN[  
{ t%lat./yT  
int n = -1; rm[C{Pn  
try{ >$4# G)s  
oSavedFile.write(b,nStart,nLen); $d?W1D<A  
n = nLen; G\@pg;0|y  
} ljKIxSvCFp  
catch(IOException e) +X=*>^G(-  
{ Y,}_LS$f  
e.printStackTrace (); Jl/wP   
} WoEK #,I;  
nq M7Is  
p~$cwbQ!  
return n; O(T5  
} $H)^o!  
4@ PA+(kvS  
Xqf,_I=V  
} |THpkfW  
:o'x?]  
o!M8V ^vW  
/* 4Z)s8sDKW  
**SiteInfoBean.java ~ bLx2=-"  
*/ \R#SoOd  
package NetFox; )'djqpM.  
%k!CjW3  
a`!Jq'  
public class SiteInfoBean { "n%s>@$  
Oidf\%!mvR  
Qm%PpQ^Lz3  
private String sSiteURL; //Site's URL m{/7)2.  
private String sFilePath; //Saved File's Path C-&ymJC|  
private String sFileName; //Saved File's Name f<YYo  
private int nSplitter; //Count of Splited Downloading File Q\$3l'W  
<`}P  
Pxlc RF  
public SiteInfoBean() %O"8|ZG9{  
{//nSplitter的缺省值为5 mO>L]<O  
//default value of nSplitter is 5 Pyo|Sgk  
this("","","",5); b:dN )m  
} 6_j |@  
 1MN!  
U2 *ORd  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) en<~_|J  
{ [l23b{  
sSiteURL= sURL; c[h~=0UtJ  
sFilePath = sPath; ]S6Gz/4aV+  
sFileName = sName; HlGSt$woX  
this.nSplitter = nSpiltter; 3!CUJs/W  
7UfNz60+~  
M8/a laoT  
} /(dP)ysc  
2JfSi2T  
./YR8#,  
public String getSSiteURL() 9d5$cV  
{ cQU/z"?+  
return sSiteURL; gEh/m.L7  
} 6nx\|F  
#D`@G8~(  
={BD*= i  
public void setSSiteURL(String value) @62T:Vl  
{ (80m'.X  
sSiteURL = value; IG^@VQ%  
} rAenx Z,tF  
28MMH Q  
J@3,  
public String getSFilePath() 7N$2N!I(  
{ wI.aV>  
return sFilePath; I ]m  
} y'R}  
;ArwEzo(  
CFtQPTw  
public void setSFilePath(String value) }%wd1`l7  
{ ZEqW*piI  
sFilePath = value; 'a~@q~!  
} QYH-"-)  
\nl(tU#j  
SI7rTJ]/  
public String getSFileName() 3c<aI =$^  
{ 78& |^sq  
return sFileName; Y ;Ym=n'  
} Xaq;d'  
hkMeUxS  
l]*RiK2AC  
public void setSFileName(String value) 7)Toj  
{ QS#@xhH  
sFileName = value; eM7@!CdA9q  
} f|d~=\0y  
\""^'pP@  
;:;E|{e  
public int getNSplitter() UK=ELvt]  
{ y=3 dGOFB  
return nSplitter; P>/:dt'GJ}  
} j\y;~ V  
Ymut]`dX  
@C;1e7  
public void setNSplitter(int nCount) !cW rB9  
{ vrs  
nSplitter = nCount; v:O{"s  
} @r"\bBi  
} mqSVd^  
}lZEdF9GhG  
%|-N{>wKy  
/* |XyX%5p*  
**Utility.java C=?S  
*/ X4;U4pU#  
package NetFox; `4"8@>D  
]!hjKu"  
]S2rqKB  
public class Utility { )2f#@0SVL  
SB62(#YR  
oF%m  
public Utility() kg/B<w'  
{ i VSNara  
U8_{MY-9}  
hRkCB  
} .D*Qu}  
-^p{J TB+  
//线程睡眠 qt8Y3:=8l  
public static void sleep(int nSecond) *!5CL'  
{ )_#V>cvNG  
try{ }\a#e^-xQ+  
Thread.sleep(nSecond); 'Ru(`" 1|  
} M.}9)ho   
catch(Exception e) =G-OIu+H!U  
{ sW>%mnx  
e.printStackTrace (); fc#9e9R  
} {lI}a8DP  
} U:7h>Z0W  
+){^HC\7h  
//日志 l+ }=D@l  
public static void log(String sMsg) -E-#@s  
{ N_Us6 X  
System.err.println(sMsg); G]lGoa}]`u  
} &PMQ]B  
[gW eD  
a&s34Pd  
public static void log(int sMsg) kWzp*<lWe  
{ ~ 'ZwD/!e  
System.err.println(sMsg); iI GK "}  
} *|rdR2R!  
} F^dJ{<yX  
2BccE  
.f~9IAXP`  
/* =*UK!y?n  
**TestMethod.java ;dIk$_FN  
*/ g]~vZj  
package NetFox; /T _M't@j  
%i9S"  
;,{ _=n>  
public class TestMethod { E$"NOR  
@@Ib^sB%  
?9 huuJ s7  
public TestMethod() (4H\ho8+mp  
{ ///xx/weblogic60b2_win.exe SioeIXU  
try{ J=A)]YE  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [S6u:;7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); fUw:jE xz  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "Q:Gd6?h;  
fileFetch.start(); x^ s,<G  
} f;E#CjlTL  
catch(Exception e){e.printStackTrace ();} t{})6  
,,H5zmgA  
VDxm|7  
} k1Y\g'1  
Ez1eGPVr  
9< mMU:  
public static void main(String[] args) Wn<?_}sa|z  
{ A7 RI&g v5  
new TestMethod(); ,TBOEu."4  
} _c>iux;  
} BM :x`JY  
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