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http断点续传简单实现(java)

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/* GeW$lA I  
**SiteFileFetch.java i{x0#6_Y  
*/ uL{~(?U$  
package NetFox; ?@ye*%w_  
import java.io.*; 1RO gUJ;  
import java.net.*; 1VM5W!}  
NCh(-E  
ur quVb  
public class SiteFileFetch extends Thread { &+|4(d1  
b5,}w:  
}\qdow-  
SiteInfoBean siteInfoBean = null; //文件信息Bean &JQ@(w  
long[] nStartPos; //开始位置 %<o$ J~l~  
long[] nEndPos; //结束位置 /xbF1@XtL  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2dlV'U_g  
long nFileLength; //文件长度 lM]),}   
boolean bFirst = true; //是否第一次取文件 H_r'q9@<>  
boolean bStop = false; //停止标志 '-~/!i+=  
File tmpFile; //文件下载的临时信息 9^h%}>  
DataOutputStream output; //输出到文件的输出流 >WS& w;G  
NqfDY  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) \36;csu  
public SiteFileFetch(SiteInfoBean bean) throws IOException [";5s&)q  
{ 7%x+7  
siteInfoBean = bean; "ddH7:(k<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); F!cAaL1  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~oR&0et  
if(tmpFile.exists ()) 10C91/  
{ '/*rCB  
bFirst = false; = y,avR  
read_nPos(); J^a"1|  
} JBJ7k19;  
else ,^Srd20  
{ J7] 60H#P  
nStartPos = new long[bean.getNSplitter()]; #\;w::  
nEndPos = new long[bean.getNSplitter()]; HPH{{p  
} ; SM^  
1 3az [  
NKh {iSLm  
:|mkI#P.  
} :pu{3-n.  
4gNRln-  
tLXw&hFk`g  
public void run() 4'=N{.TtO  
{ ._nKM5.  
//获得文件长度 >o= p5#{  
//分割文件 R}26"+~  
//实例FileSplitterFetch TmZ[?IL,  
//启动FileSplitterFetch线程 E.bbIV6mQ  
//等待子线程返回 */e5lRO\  
try{ R51!j>[fqM  
if(bFirst) N9|.D.#MF  
{ Oo .Qz   
nFileLength = getFileSize(); ~ b_gwJ'  
if(nFileLength == -1) #iDFGkK/  
{ ! HC<aWb  
System.err.println("File Length is not known!"); BT#g?=n#`  
} }f'1x%RS^  
else if(nFileLength == -2) j}*+-.YF  
{ JB_`lefW,'  
System.err.println("File is not access!"); @h,$&=HY  
} ~8{3Fc0  
else bD-Em#>  
{ <\EfG:e  
for(int i=0;i<nStartPos.length;i++) GLF"`M/g  
{ lM%fgyX  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); oA%[x  
} j'x{j %U  
for(int i=0;i<nEndPos.length-1;i++) Y/(-mcR  
{ 1 *CWHs  
nEndPos = nStartPos[i+1]; ,LO-!\L  
} B9-[wg#0G  
nEndPos[nEndPos.length-1] = nFileLength; ][1u:V/ U  
} ]*U')  
} r,KK%B  
-y.AJ~T  
~{Bi{aK2  
//启动子线程 [![ (h %  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; A\.*+k/B  
for(int i=0;i<nStartPos.length;i++) !c($C   
{ f~9Y1|6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), $3B?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O3: dOL/C  
nStartPos,nEndPos,i); VrxH6Y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Acv{XnB  
fileSplitterFetch.start(); elB 8   
} lHqx}n@e  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~]M"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); VAt9JE;#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H12@12v  
nEndPos = " + nFileLength); 8E[`H  
// fileSplitterFetch[nPos.length-1].start(); 1z:N$O _v  
x&vD,|V!  
LL [>Uu?Y  
//等待子线程结束 Uroj%xN  
//int count = 0; aB'@8[]z  
//是否结束while循环 (=/;rJ`q  
boolean breakWhile = false; MT0{hsuK9  
R*m" '|U  
IBh~(6  
while(!bStop) R!G7;m'N1  
{ Yk?q7xuT  
write_nPos(); G'f"w5%qZv  
Utility.sleep(500); $SR]7GZ  
breakWhile = true; N2e<Y_T  
%T\x~)  
n<*]`do,w  
for(int i=0;i<nStartPos.length;i++) %Ege^4PE  
{ J7vpCw2ni  
if(!fileSplitterFetch.bDownOver) [+z:^a1?V  
{ eov-"SJB  
breakWhile = false; .YF-t`{  
break; #+k[[; 0  
} yFsXI0I[p  
} pnJT]?},  
if(breakWhile) qTF>!o #\:  
break; 3PffQ,c[~  
Z+(V \  
xltu g##  
//count++; FG:BRS<m~  
//if(count>4) ppKCY4  
// siteStop(); 1+($"$ZC&B  
} Beg5[4@  
d2sq]Q  
)xy6R]_b  
System.err.println("文件下载结束!"); |vzWSm  
} pN_!&#|+$  
catch(Exception e){e.printStackTrace ();} [CX?Tt  
} & jvG]>CS'  
Sw'?$j^3  
lJ#>Y5Qg  
//获得文件长度 RC%r7K f  
public long getFileSize() U$uO%:4%  
{ d?Cl04  
int nFileLength = -1; /|AuI qW  
try{ ' qE  
URL url = new URL(siteInfoBean.getSSiteURL()); 0B/a$NC  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 06 s3 b  
httpConnection.setRequestProperty("User-Agent","NetFox"); g<%-n,  
&y\2:IyA  
#" -^;Z  
int responseCode=httpConnection.getResponseCode(); yfQE8v+  
if(responseCode>=400) eCD,[At/  
{ HC,@tfS  
processErrorCode(responseCode); f@L{*Upj+  
return -2; //-2 represent access is error b%j:-^0V  
} BwD1}1jp  
^/vWK\-  
3=7h+ZgB  
String sHeader; krc!BK`V  
^#se4qQ  
-74T C  
for(int i=1;;i++) >/bK?yT<  
{ _B FX5ifK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); K9'*q3z  
//Utility.log(in.readLine()); 8-YrmP2k  
sHeader=httpConnection.getHeaderFieldKey(i); WEAXqDjM  
if(sHeader!=null) S\gP=.G  
{ *wcoDQ b;  
if(sHeader.equals("Content-Length")) 7g+]  
{ %tQ{Hf~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Qe.kN dT+_  
break; ^?[<!VBI  
} _\PoZ|G4y  
} E,yK` mPp^  
else VTfaZ/e.  
break; REBDr;tv  
} j],.`Y  
} tta0sJ8 i  
catch(IOException e){e.printStackTrace ();} ] Nipo'N;  
catch(Exception e){e.printStackTrace ();} aZ`ags ofk  
; @~*z4U  
:Xh`.*{EX  
Utility.log(nFileLength); @$Kq<P  
,8nZzVo  
,s&~U<Z  
return nFileLength; SJ^?D8  
} iDc|9"|Tf3  
?Zp!AV  
1[9j`~[([  
//保存下载信息(文件指针位置) Nj&%xe>].  
private void write_nPos() ^|(4j_.(e  
{ <W') ~o}  
try{ ;XQ lj?:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); X>8?p'*  
output.writeInt(nStartPos.length); fhx:EZ:~  
for(int i=0;i<nStartPos.length;i++) pu*u[n  
{ 8w?\_P7QA  
// output.writeLong(nPos); ;I71_>m  
output.writeLong(fileSplitterFetch.nStartPos); g@VndAp  
output.writeLong(fileSplitterFetch.nEndPos); _rdj,F8  
} D#}Yx]Q1  
output.close(); Am0C|(#Xm  
} m@yVG|eP#  
catch(IOException e){e.printStackTrace ();} _k.bGYldk  
catch(Exception e){e.printStackTrace ();} Jd"s~n<>K  
} N4|q2Jvj6  
,!u@:UBT  
i9k]Q(o  
//读取保存的下载信息(文件指针位置) y$V)^-U>fw  
private void read_nPos() U*"cf>dB(  
{ vD9D:vK  
try{ 05I39/T%  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 2BA9T nxC  
int nCount = input.readInt(); - :z5m+  
nStartPos = new long[nCount]; 4@iJ|l  
nEndPos = new long[nCount]; ruA+1-<f  
for(int i=0;i<nStartPos.length;i++) 13_~)V  
{ bRz^=  
nStartPos = input.readLong(); RXS|-_$  
nEndPos = input.readLong(); *oX]=u&  
} pQ(eF0KG  
input.close(); Ss! 3{VW  
} 5=h'!|iY  
catch(IOException e){e.printStackTrace ();} 1$D`Z/N"A  
catch(Exception e){e.printStackTrace ();} e0WSHg=6@  
} |aAWW d5  
=C>`}%XT}  
|abst&yp  
private void processErrorCode(int nErrorCode) U3+ _'"  
{ <i\zfa'6  
System.err.println("Error Code : " + nErrorCode); 'Mx K}9  
} 3]OP9!\6  
D6)Cjc>a  
S*m`'  
//停止文件下载 ^~<Rzq!  
public void siteStop() RzJ}CT  
{ p6y0W`U  
bStop = true; &DQ4=/Z  
for(int i=0;i<nStartPos.length;i++) pkN:D+g S  
fileSplitterFetch.splitterStop(); skD k/-*R  
v&b.Q:h*'  
VFmg"^k5  
} 2*q: ^  
} 3 [)s;e  
//负责部分文件的抓取 _Z66[T+M  
**FileSplitterFetch.java KD"&_PX  
*/ 26#Jhb E+  
package NetFox; /.kna4k  
nHA`B.:B  
}8F$& AFt  
import java.io.*; tGO[A#9a  
import java.net.*; ^A "lkV7  
K l0tyeT  
J6( RlHS;  
public class FileSplitterFetch extends Thread { +>WC^s  
qz=#;&ZU  
1'v!9  
String sURL; //File URL keQXJ0  
long nStartPos; //File Snippet Start Position m$E^u[  
long nEndPos; //File Snippet End Position U|Z>SE<k  
int nThreadID; //Thread's ID ')u5l  
boolean bDownOver = false; //Downing is over XL7;^AE^Wl  
boolean bStop = false; //Stop identical 9oz(=R  
FileAccessI fileAccessI = null; //File Access interface ,D@ ;i  
f5yux}A{  
W93JY0Ls9|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &I}T<v{f  
{ Q),3&4pM  
this.sURL = sURL; [71#@^ye  
this.nStartPos = nStart; `zzKD2y  
this.nEndPos = nEnd; *L;pcg8{  
nThreadID = id; !V]MLA`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 MB8SB   
} i2FD1*=/?  
q1TW?\pjb:  
:e&n.i^  
public void run() 1] %W\RHxo  
{ @ k+%y'Y?  
while(nStartPos < nEndPos && !bStop) K(Q]&&<  
{ X<Th{kM2  
*TM;trfz  
t8DL9RW'  
try{ hEv=T'*,K)  
URL url = new URL(sURL); i+)}aA  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &}nBenYp  
httpConnection.setRequestProperty("User-Agent","NetFox"); < g3du~  
String sProperty = "bytes="+nStartPos+"-"; %kK ][2e  
httpConnection.setRequestProperty("RANGE",sProperty); ws>WA{]gq  
Utility.log(sProperty); $"sq4@N  
~MhgAC  
crJ7pe9  
InputStream input = httpConnection.getInputStream(); JQ"`9RNb  
//logResponseHead(httpConnection); hgweNRTh!  
"?.'{,Q  
7b&JX'`Mb  
byte[] b = new byte[1024]; 't|Un G  
int nRead; TvunjTpaj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ([,vX"4  
{ MX!u$ei  
nStartPos += fileAccessI.write(b,0,nRead); %XP_\lu]  
//if(nThreadID == 1) sK`~Csb iB  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \~@[QGKN  
} }W:*aU  
9Z,*h-o  
+Lm3vj_ N  
Utility.log("Thread " + nThreadID + " is over!"); 1B)Y;hg6&  
bDownOver = true; Iv$:`7|crX  
//nPos = fileAccessI.write (b,0,nRead); bZNIxkc[Dh  
} ;wij}y-6  
catch(Exception e){e.printStackTrace ();} ,vPe}OKj  
} _tWJXv~;  
} DtzA$|Q}  
hLb;5u&!kW  
(jU/Wj!q  
//打印回应的头信息 \Fj5v$J-  
public void logResponseHead(HttpURLConnection con) -VS9`7k  
{ C#MF pT  
for(int i=1;;i++) M{`/f@z(  
{ :s'o~   
String header=con.getHeaderFieldKey(i); -O|&c9W.O  
if(header!=null) -DTB6}kw  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /> ^@ O  
Utility.log(header+" : "+con.getHeaderField(header)); Yim{U:F  
else ;i<$7MR.e  
break; ic%?uWN  
} .6>  hD1'  
} 3B@y &a#&  
*#3*;dya]  
&|v{#,ymeb  
public void splitterStop() PX;Vo~6  
{ 3/X-Cr+d  
bStop = true; `J72+RA  
} wgCvD  
)O,wRd>5  
CF]i}xpWV  
} =%!e(N'p  
N>+P WE$  
S8 :"<B)  
/* &J8 Z@^  
**FileAccess.java hf;S]8|F  
*//文件访问(定位,写) Q*]$)D3n  
package NetFox; 6}ce1|mkg/  
import java.io.*; 1hl]W+9  
B\\6#  
!7}IqSs  
public class FileAccessI implements Serializable{ /-h6`@[  
z5x _fAT(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 U1OFDXHG  
RandomAccessFile oSavedFile; c\At0.QCA  
long nPos; AgIazv1  
^NXcLEaP*<  
Rv=DI&K%n  
public FileAccessI() throws IOException ~@{w\%(AK]  
{ <"W?<VjO  
this("",0); [+;qWfs B  
} {@?G 9UypA  
Ck: 9gn  
X*i/A<Y`=  
public FileAccessI(String sName,long nPos) throws IOException / /'Tck  
{ :z]}ZZ  
oSavedFile = new RandomAccessFile(sName,"rw"); ?AEd(_a!q  
this.nPos = nPos; -;^;2#](g  
oSavedFile.seek(nPos); nSS>\$  
} P` #QGZ>  
[r(Qs|  
r#A_RZ2~@  
public synchronized int write(byte[] b,int nStart,int nLen) 7KU~(?|:h  
{ z"lqrSJ:  
int n = -1; /RGNAHtIi  
try{ @}WNKS&m  
oSavedFile.write(b,nStart,nLen); blGf!4H  
n = nLen; *I0Tbc O  
} ] /+D^6  
catch(IOException e) %?bcT[|3  
{ u_PuqRcs  
e.printStackTrace (); &-M]xo ^  
} f|U0s  
baee?6  
+iy7e6P  
return n; Zmf'{tT5  
} $$hv`HE^l  
Ur^j$B}  
@9Q2$  
} 'B_\TU0 O  
qos`!=g?  
1~J5uB4  
/* 5!Bktgk.  
**SiteInfoBean.java IS BV%^la|  
*/ MM?`voj~`p  
package NetFox; Rs*v m  
6-B 9na  
m#f{]+6U  
public class SiteInfoBean { c8{]]  
f6!D L<  
3NIUW!gr  
private String sSiteURL; //Site's URL Tv5g`/e=Ej  
private String sFilePath; //Saved File's Path mf' ]O,  
private String sFileName; //Saved File's Name dA_YL?o r  
private int nSplitter; //Count of Splited Downloading File @m~RtC-Q  
?7jg(`Yh  
aQ#qRkI  
public SiteInfoBean() WA$ JI@g  
{//nSplitter的缺省值为5 >xu [q\:"  
//default value of nSplitter is 5 fr[3:2g-_  
this("","","",5); r[_4Lo @G  
} "CQw/qZw  
|Ps% M|8~  
[mUBHYD7OI  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N j4IQ<OV  
{ ,Q/Ac{C  
sSiteURL= sURL; W2Luz;(U  
sFilePath = sPath; :B|Dr v  
sFileName = sName; Lq (ZcEKo  
this.nSplitter = nSpiltter; LZ U$  
9b;A1gu  
QvLZg  
} Sm-wH^~KA  
FJNF%a)x2I  
5,pSg  
public String getSSiteURL() %zeATM[`  
{ C`V)VJM  
return sSiteURL; T*~H m  
} % UZVb V  
C+{l7QT$t  
'9?;"=6(  
public void setSSiteURL(String value) EE=3  
{ ZH,4oF  
sSiteURL = value; w$|l{VI  
} dQb.BOI)h  
N ]N4^A'  
Nt:9MG>1  
public String getSFilePath() LfLFu9#:w  
{ 6rN(_Oi-  
return sFilePath; B[5r|d'  
} xJZ@DR,#  
X|DO~{-au  
x9W(cKB'S  
public void setSFilePath(String value) /mM2M-  
{ O 5 Nb  
sFilePath = value; }(XdB:C8  
} kJQ#Wz|z]  
q<#>HjC  
vuQ%dDxI  
public String getSFileName() -e u]:4  
{ ]@^coj[  
return sFileName; oU6y4yO  
} r\`+R"  
oslJC$cy'  
a`(a)9i  
public void setSFileName(String value) =PHIpFIuk  
{ 7piuLq+  
sFileName = value; m~hoE8C$  
} s;flzp8  
6\jf|:h  
}MbH3ufC  
public int getNSplitter() Q,h7Sk*  
{ C1EtoOv K  
return nSplitter; 76cG90!Z  
} k0-G$|QgIp  
cLY c6  
qU6nJi+-I  
public void setNSplitter(int nCount) US [dkbKo  
{ Gfp1mev   
nSplitter = nCount; +;}#B~:  
} L I>(RMv  
} )~6zYJ2  
W5L iXM  
7Q w|!  
/* 6x)$Dl  
**Utility.java !R-z%  
*/ s@hRqGd:  
package NetFox; D}C,![   
'_k+WH&  
:!a 2]-D}  
public class Utility { '})0!g<Y  
P|tNL}2`;  
`+:.L>5([  
public Utility() wa=uUM_4u^  
{ 3@Z#.FV~C[  
S& #U!#@  
(+<1*5BEkT  
} h N2:d1f0  
wkqX^i7ls  
//线程睡眠 Cv ejb+  
public static void sleep(int nSecond) ?Iyo9&1&  
{ )}vNOE?X~  
try{ ps .]N   
Thread.sleep(nSecond); 'J&f%kx"  
} v[plT2"s  
catch(Exception e) h7*W *Bd  
{ `Q3s4VEC  
e.printStackTrace (); l!}:|N Yh!  
} -<v~snq'  
} `@[c8j7  
4wd& 55=2  
//日志 2&c9q5.b  
public static void log(String sMsg) ZOXIT(mg  
{ 'Jf^`ZT}  
System.err.println(sMsg); !zj0/Q G\  
} /xGmg`g<#  
0;4t&v7  
@_:]J1jw7  
public static void log(int sMsg) ~_s?k3cd  
{ 'TH15r@  
System.err.println(sMsg); 6hZ@;Q=b  
} [gy*`@w  
} T,xPSN2A*  
*_E|@y  
cLPkK3O\=  
/* K7Rpr.p  
**TestMethod.java \Y6WSj?E  
*/ bY}eUL2i4  
package NetFox; 'XY`(3q  
YEkh3FrbwH  
.<tquswg  
public class TestMethod { {-|{xBd  
SS`qJZ|w  
F:y[@Yn  
public TestMethod() F":r4`5D"K  
{ ///xx/weblogic60b2_win.exe `qd+f{Q  
try{ b=~i)`  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); D +_oVob\  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ~4P%%b0,o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); K=!Bh*  
fileFetch.start(); fwK}/0%  
} (b'B%rFO  
catch(Exception e){e.printStackTrace ();} V $z} K  
=@k%&* Y?  
upj]6f"(  
} d*)CT?d&  
yQ#:J9HMJ  
={LMdC~5X  
public static void main(String[] args) yG Wnod'  
{ ` PYJ^I0  
new TestMethod(); Z2im@c67{  
} TuW%zF/  
} J|'7_0OAx  
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