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http断点续传简单实现(java)

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/* [C*X k{e  
**SiteFileFetch.java 4kN:=g  
*/ pJ<)intcbE  
package NetFox; :{e`$kz  
import java.io.*; `0/gs  
import java.net.*; [xH2n\7  
U/~Zk@3j  
`0-m`>1>  
public class SiteFileFetch extends Thread { p)AvG;  
*>R/(Q  
J@&$U7t  
SiteInfoBean siteInfoBean = null; //文件信息Bean G!fE'B  
long[] nStartPos; //开始位置 )xXrs^  
long[] nEndPos; //结束位置 wZ#~+ }T  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *AJezhR  
long nFileLength; //文件长度 FL*w(Br.  
boolean bFirst = true; //是否第一次取文件 2T{-J!k  
boolean bStop = false; //停止标志 Z2Y583D  
File tmpFile; //文件下载的临时信息 R _~m\P  
DataOutputStream output; //输出到文件的输出流 ~vvQz"  
^~hhdwu3a  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) }@t'rK[  
public SiteFileFetch(SiteInfoBean bean) throws IOException ocuNrkZ  
{ 1+y6W1m^R  
siteInfoBean = bean; A+Pm "|  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jmwQc&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?F_;~  
if(tmpFile.exists ()) }<x!95  
{ _yXeX  
bFirst = false; -n$rKEC4  
read_nPos(); clU3#8P!=  
} :j50]zLy{  
else I;fw]/M%!  
{ pOe`*2[  
nStartPos = new long[bean.getNSplitter()]; \Q BpgMi(  
nEndPos = new long[bean.getNSplitter()]; U Edl"FwM4  
} ^_"q`71Dk  
q?'gwH37  
I}CA-8  
3[g++B."pC  
} '%r@D&*vp  
{83He@  
]> "/<"  
public void run() kl<B*:RqH  
{ q.K$b  
//获得文件长度 u:>3j,Cs  
//分割文件 i{x0#6_Y  
//实例FileSplitterFetch "a_D]D(d5  
//启动FileSplitterFetch线程 -JW6@L@  
//等待子线程返回 ^T J   
try{ f0`rJ?us  
if(bFirst) >"My\o  
{ vrEaNT$J-  
nFileLength = getFileSize(); 7)8}8tY^{  
if(nFileLength == -1) [LEh  
{ wjGjVTtHs  
System.err.println("File Length is not known!"); ~m=%a  
} Oh85*3  
else if(nFileLength == -2) m.g@S30  
{ qc4 "0Ap'  
System.err.println("File is not access!"); QZq9$;>dW  
} ;77o%J'l  
else '|R@k_nx  
{ $Lbe5d?\  
for(int i=0;i<nStartPos.length;i++) 10C91/  
{ ZUI\0qh+  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l,2z5p  
} 3tcsj0Rb  
for(int i=0;i<nEndPos.length-1;i++) %YAiSSsV  
{ Y,"MQFr(o  
nEndPos = nStartPos[i+1]; 1 3az [  
} M HB]'  
nEndPos[nEndPos.length-1] = nFileLength; E"yf!*  
} 9{#|sABGD  
} "8 mulE,  
.v&h>@'m  
j7 3@Yi%  
//启动子线程 beR)8sC3q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; */e5lRO\  
for(int i=0;i<nStartPos.length;i++) twS3J)UH  
{ `5&V}"lB  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )t=u(:u]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 0>MI*fnY"  
nStartPos,nEndPos,i); Czxrn2p/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .*7UT~o=CS  
fileSplitterFetch.start(); <5}du9@  
} /j@r~mt/pA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), LkB!:+v |B  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xJGeIh5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \ \}/2#1=c  
nEndPos = " + nFileLength); kweTK]mT  
// fileSplitterFetch[nPos.length-1].start(); B9-[wg#0G  
Z!eq/  
F ;&e5G  
//等待子线程结束 k4rB S  
//int count = 0; A\.*+k/B  
//是否结束while循环 >MrU^t  
boolean breakWhile = false; =lD]sk  
=1[g`b  
L:Eb(z/D  
while(!bStop) 5^/[]*  
{ *b_54X%3  
write_nPos(); jtY~- @*  
Utility.sleep(500); Af<>O$$6  
breakWhile = true; 1U7HS2  
N|S xAg  
Uroj%xN  
for(int i=0;i<nStartPos.length;i++) i8.[d5  
{ V5 r7eC  
if(!fileSplitterFetch.bDownOver) qQvb;jO  
{ uJ[Vv4N%9  
breakWhile = false; 1?\Y,+  
break; 3>Snd9Q  
} F k;su,]_  
} v{ Ve sf  
if(breakWhile) ,&G M\FTeb  
break; NkI:  
7bS[\5  
zmRK%a(  
//count++; ^ ni_%`Ag  
//if(count>4) 7d)' y  
// siteStop(); au* jMcq  
} eS:e#>(  
Kf~+jYobO  
yw!`1#3.  
System.err.println("文件下载结束!"); p]=;t"  
} Sw'?$j^3  
catch(Exception e){e.printStackTrace ();} IOl"Xgn5  
} ^j}sS!p  
Iq \oB  
0B/a$NC  
//获得文件长度 1A-EP@# J  
public long getFileSize() [{$0E=&0  
{ S '+"+%^tj  
int nFileLength = -1; MX,0gap  
try{ rK|&u v*b  
URL url = new URL(siteInfoBean.getSSiteURL()); "s9gQAoaO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V.:A'!$#  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ypj)6d  
>/bK?yT<  
%QLYNuG  
int responseCode=httpConnection.getResponseCode(); # HYkzjb  
if(responseCode>=400) x`i`]6q  
{ y:[]+  
processErrorCode(responseCode); [HDO^6U  
return -2; //-2 represent access is error o1+]6s+j}  
} w[YbL2p  
e}AJxBE  
L-{r*ccIW  
String sHeader; \w[%n0  
S'p`ECfVMA  
; @~*z4U  
for(int i=1;;i++) N\p]+[6  
{ dvF48,kr  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); SJ^?D8  
//Utility.log(in.readLine()); N~_jiVD>  
sHeader=httpConnection.getHeaderFieldKey(i); -GVG1#5  
if(sHeader!=null) '$-,;vnP0  
{ ?u!AHSr(  
if(sHeader.equals("Content-Length")) =2)t1 H  
{ u@u.N2H.%  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); w1(06A}/  
break; {bqKb=nyZ  
} D#}Yx]Q1  
} [iy;}5XK  
else f<p4Pkv  
break; #gJ~ {tA:  
} wD^do  
} .|`=mx  
catch(IOException e){e.printStackTrace ();} C-^%g [#  
catch(Exception e){e.printStackTrace ();} ^6y4!='ci  
ruA+1-<f  
<;E[)tv  
Utility.log(nFileLength); e - ]c  
E816 YS='  
@EOR] ^?!]  
return nFileLength; 1za'u_  
} i)PV{3v$J  
lc?mKW9  
O| 6\g>ew  
//保存下载信息(文件指针位置) q&d&#3Rh  
private void write_nPos() 39aCwhh7v  
{ JBEgiQ/  
try{ p6y0W`U  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (X_,*3Yxk  
output.writeInt(nStartPos.length); j[J@tM#  
for(int i=0;i<nStartPos.length;i++) }-q`&1!t  
{ 3 [)s;e  
// output.writeLong(nPos); 0Q- Mxcj  
output.writeLong(fileSplitterFetch.nStartPos); 2]aZe4H.  
output.writeLong(fileSplitterFetch.nEndPos); ^&';\O@)  
} Ma=6kX]  
output.close(); H(G^O&ppdB  
} ]pRfY9w  
catch(IOException e){e.printStackTrace ();} +>WC^s  
catch(Exception e){e.printStackTrace ();} %6IlE.*,  
} k4F"UG-`  
*iRm`)zC(  
<V:<x  
//读取保存的下载信息(文件指针位置) ,D@ ;i  
private void read_nPos() 0fPHh>u  
{ }EedHS  
try{ y LgKS8b  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); g#'fd/?Q  
int nCount = input.readInt(); *L;pcg8{  
nStartPos = new long[nCount]; {NY~JFM  
nEndPos = new long[nCount]; }6CXJ+-UR  
for(int i=0;i<nStartPos.length;i++) ,bVS.A'o  
{ EAD0<I<>  
nStartPos = input.readLong(); gVnws E  
nEndPos = input.readLong(); eN]>l  
} Kl aZZJ  
input.close(); ||=[kjG~  
} rW FcIh5  
catch(IOException e){e.printStackTrace ();} KZrMf77=  
catch(Exception e){e.printStackTrace ();} AvrL9D  
} `*" H/QG  
0;FqX*  
J+71FP`ZH  
private void processErrorCode(int nErrorCode) 8R\>FNk;  
{ g= FDm*  
System.err.println("Error Code : " + nErrorCode); =&q-[JW  
} p<=(GY-  
ePq13!FC/  
g5tjj.  
//停止文件下载 X-)RU?  
public void siteStop() .~.``a  
{ j\`EUC  
bStop = true; r zMFof  
for(int i=0;i<nStartPos.length;i++) v[{8G^Z}54  
fileSplitterFetch.splitterStop(); AV:Xg4UJv  
RgB6:f,  
rU=b?D)n!w  
} gDQkn {T.%  
} +Lm3vj_ N  
//负责部分文件的抓取 1R=)17'O  
**FileSplitterFetch.java V~(EVF{h  
*/ &W=V%t>Z  
package NetFox; -{X<*P4p  
m:)Z6  
.FIt.XPzv  
import java.io.*; DtzA$|Q}  
import java.net.*; )uQ-YC('0  
0a"igH}  
x9&-(kBU  
public class FileSplitterFetch extends Thread { M{`/f@z(  
YfE>Pn'r  
9$7&URwSDI  
String sURL; //File URL 4$yV%[j  
long nStartPos; //File Snippet Start Position WnD^F>  
long nEndPos; //File Snippet End Position 01U *_\  
int nThreadID; //Thread's ID Jy \2I{I'  
boolean bDownOver = false; //Downing is over )^4ko  
boolean bStop = false; //Stop identical "pt+Fe|@c;  
FileAccessI fileAccessI = null; //File Access interface )O,wRd>5  
;wJ~haC  
sK+ (v  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException OnZF6yfN=3  
{ Q*]$)D3n  
this.sURL = sURL; Z+g1~\  
this.nStartPos = nStart; 4L8z>9D  
this.nEndPos = nEnd; _|N}4a  
nThreadID = id; sU\c#|BSC"  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 UQ/qBbn  
} k!5m@'f  
vt//)*(.$  
>D 97c|?c  
public void run() LH4>@YPGE#  
{ K*~]fy  
while(nStartPos < nEndPos && !bStop) COR;e`%,  
{ M :V2a<!c  
~ |6dH  
+ :Vrip  
try{ ][,4,?T7  
URL url = new URL(sURL); P''X_1oMC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "NDxgJ%J35  
httpConnection.setRequestProperty("User-Agent","NetFox"); "< v\M85&  
String sProperty = "bytes="+nStartPos+"-"; (:5G#?6,  
httpConnection.setRequestProperty("RANGE",sProperty); U[R@x`  
Utility.log(sProperty); 9M_(He -  
f;gZ|a  
b.s9p7:J  
InputStream input = httpConnection.getInputStream(); 1"}cdq.  
//logResponseHead(httpConnection); .e @>   
Cp#)wxi6[y  
5!Bktgk.  
byte[] b = new byte[1024]; ' _dzcN,z  
int nRead; 3J{vt"dS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) -?<4Og[^  
{ LvJGvj  
nStartPos += fileAccessI.write(b,0,nRead); 9AHSs,.t  
//if(nThreadID == 1) 9I`Y-D  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *XbI#L%>  
} + E/y ~s  
eWvo,4  
`Gd$:qV  
Utility.log("Thread " + nThreadID + " is over!"); /4$4h;_8  
bDownOver = true; ?7[alV~  
//nPos = fileAccessI.write (b,0,nRead); e}0:"R%E  
} at6149B\)  
catch(Exception e){e.printStackTrace ();} /\Z J   
}  )zq.4  
} N j4IQ<OV  
kS :\Oz\  
:?Y$bX}a  
//打印回应的头信息 WKmbNvN^  
public void logResponseHead(HttpURLConnection con) 4f^C\i+q  
{ FJNF%a)x2I  
for(int i=1;;i++) Bfr'Zdw  
{ PUdM[-zjh  
String header=con.getHeaderFieldKey(i); \}_Yd8  
if(header!=null) 93O;+Z5J  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ZH,4oF  
Utility.log(header+" : "+con.getHeaderField(header)); N^w'Hw0  
else R?66b{O  
break; G{9X)|d  
} =Z G:x<Hg  
} Ucdj4[/,h  
rw7_5l  
b;GD/UI  
public void splitterStop() ?=;qK{)37  
{ =Gk/k}1  
bStop = true; ;8{cA_&  
} gEQNs\Jn L  
B>y9fI  
o*g|m.SjL  
} h*B|fy4K9U  
nqVZqX@oE  
hsKmnH@#  
/* {yA$V0`N{  
**FileAccess.java k0-G$|QgIp  
*//文件访问(定位,写) e`>{$t  
package NetFox; b6(p  
import java.io.*; SLfFqc+n0  
sOCs13A"  
u{N,Ib 8  
public class FileAccessI implements Serializable{ gk[{2HgN  
6 15s5ZA  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !QI\Fz?  
RandomAccessFile oSavedFile; =qy=-j]  
long nPos; bI)u/  
iJ' xh n  
 7R#+Le)  
public FileAccessI() throws IOException dC\ZjZZ  
{ *=V7@o  
this("",0); hI?sOR!  
} A\_|un%  
^.k |SK`U  
h7*W *Bd  
public FileAccessI(String sName,long nPos) throws IOException cKb)VG^  
{ /2EHv.e `  
oSavedFile = new RandomAccessFile(sName,"rw"); -Y Bd, k3  
this.nPos = nPos; uXDq~`S  
oSavedFile.seek(nPos); 6 5y+Z  
} pD]0`L-HJU  
rqP FU6  
'TH15r@  
public synchronized int write(byte[] b,int nStart,int nLen) ac kqH+'  
{ *_E|@y  
int n = -1; jdE5~a+  
try{ oI)GKA_Ng7  
oSavedFile.write(b,nStart,nLen); p~noM/*2r  
n = nLen; O=SkAsim  
} Xc"&0v%;#  
catch(IOException e) b@3_L4~  
{ k+I}PuG  
e.printStackTrace (); "&+"@ <  
} V[-jD8=' 3  
iyj+:t/  
&Ysosy*  
return n; \U|ZR  
} vad12WrG<  
+f*OliMD  
8NaqZ+5x  
} 6[OzU2nB  
~QvqG{bFB  
Y0 D}g3`  
/* c@v{`d  
**SiteInfoBean.java dnV[ P  
*/ P!"&%d  
package NetFox; vjjSKP6B  
sdQkT#%y  
F(t=!k,4\  
public class SiteInfoBean { fN'HE#W1Xa  
vN3Zr34  
N^Bo .U0\  
private String sSiteURL; //Site's URL !S&L*OH,  
private String sFilePath; //Saved File's Path  o x+ 3U  
private String sFileName; //Saved File's Name 2h[85\4  
private int nSplitter; //Count of Splited Downloading File gY@N~'f;"  
UQB "v3Z  
rj6#1kt  
public SiteInfoBean() 4lBU#V7  
{//nSplitter的缺省值为5 e9Nk3Sj]  
//default value of nSplitter is 5 IpP~Uz  
this("","","",5); -?(E_^ng  
} R'S0 zp6  
B" 3dQwQ  
u%.$BD Hg  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?JL:CBvCp  
{ ,_"AT! r  
sSiteURL= sURL;  A^p[52`  
sFilePath = sPath; 44-R!  
sFileName = sName; Q'%PNrN  
this.nSplitter = nSpiltter; /% N r?V  
`X3^fg  
1x[)/@.'f  
} ^a#X9  
6 ~ >FYX  
_cu:aktf2  
public String getSSiteURL() TC<@e<-%Sq  
{ gB<3-J1R  
return sSiteURL; e*L.U~ZR  
} up'Tit  
K# Jk _"W  
QR>gt;  
public void setSSiteURL(String value) 9~l hsH  
{ !%c'$f/  
sSiteURL = value; :rg5Kt&  
} 8cA~R-  
]8T!qS(UJd  
yV"ZRrjO'Z  
public String getSFilePath() *W kIq>  
{ ,u/aT5\_  
return sFilePath; SCz(5[MZJ  
} 1|ra&(=)  
8HP6+c%  
:hM/f  
public void setSFilePath(String value) pZeE61c/  
{ E <c9#I=  
sFilePath = value; L =8rH5  
} f-%NaTI  
Hbpqyl%O>  
5:kH;/U  
public String getSFileName() !=N"vD*  
{ NM06QzE  
return sFileName; R%'^gFk 8  
} Kh MSL  
\.3D~2cU  
yfm^?G|sW  
public void setSFileName(String value) )4&cph';  
{ >hr{JJe  
sFileName = value; 3.qTLga|}  
} p1|f<SF')  
Rb{U+/gq  
=X.9,$Y  
public int getNSplitter() ;dzL}@we  
{ WAS U0  
return nSplitter; vo#UtN:q  
} 9F*+YG!  
a(0*um(  
('hE r~&  
public void setNSplitter(int nCount) xa pq*oj  
{ ?G -e](]^<  
nSplitter = nCount; G 8V,  
} Y k5 }`d!:  
} %y%j*B!%  
)kkhJI*v  
.3MIcj=p  
/* 7K5P8N ,  
**Utility.java Gqy,u3lE  
*/ 0JJS2oY/  
package NetFox; zBe8,, e  
a! u rew#  
&T}''  
public class Utility { a@0BBihz  
w18y}mS"H  
?A )hN8  
public Utility() Jyqc2IH  
{ 'GL*u#h  
 BouTcC  
)u qA(R>  
} qvv2O1c"A  
= hN !;7G  
//线程睡眠 PxfY&;4n!  
public static void sleep(int nSecond) m ]cHF.:5  
{ "|HDGA5  
try{ xSBc-u#< G  
Thread.sleep(nSecond); U_{Ux 2  
} g{P%s'%*  
catch(Exception e) Y}vr>\  
{ "&%#!2  
e.printStackTrace (); !0dNQ[$82  
} =lVK IW  
} uy}%0vLo  
7H|$4;X^  
//日志 3yNU$.g  
public static void log(String sMsg) A2n qf^b{#  
{ ~wVd$%7`  
System.err.println(sMsg); m{7(PHpw  
} nO)X!dp}J  
0p@k({]<  
;IpT} ,  
public static void log(int sMsg) !S_^94b@  
{ c-Pw]Ju  
System.err.println(sMsg); .YZgOJi  
} R+7oRXsu  
} po}F6m8bX  
BY]i;GVq  
q@jq0D)g  
/* =Z+nX0qF  
**TestMethod.java E(i[o?  
*/ )<xypDQ  
package NetFox;  3S&U!  
TET`b7G  
0JD~M\-!^a  
public class TestMethod { .&x}NYX4  
7^Yk`Z?|a  
8Mbeg ,P  
public TestMethod() >[1W:KQA  
{ ///xx/weblogic60b2_win.exe nIvJrAm4k  
try{ /QEiMrz@6  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /o2P+Xr8"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); $8crN$ye  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ^`D=GF^tX  
fileFetch.start(); GAc{l=vT'  
} @EoZI~  
catch(Exception e){e.printStackTrace ();} dCFlM&(i  
W@2vjz  
\-*eL;qP  
} nL?oTze*p  
Tb1U^E:  
[Ym   
public static void main(String[] args) SAY f'[|w  
{ ~xIj F1Z  
new TestMethod(); v~/~ @jv  
} J/6`oh?,Q  
} RJeSi`19T)  
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