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http断点续传简单实现(java)

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/* 10a=YG  
**SiteFileFetch.java wt3Z?Pb  
*/ bF8xQ<i~Y  
package NetFox; h[M6.  
import java.io.*; &eLQ;<qO*|  
import java.net.*; I{Y {  
BdRE*9.0  
g6k&c"%IQ(  
public class SiteFileFetch extends Thread { gXJ19zB+  
;8 /+wBnm  
uH~ TugQ~  
SiteInfoBean siteInfoBean = null; //文件信息Bean (PE8H~d  
long[] nStartPos; //开始位置 %$!R]B)  
long[] nEndPos; //结束位置 jQw`*Y/,  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 %^)JaEUC  
long nFileLength; //文件长度 NC[GtAPD3  
boolean bFirst = true; //是否第一次取文件 Sj=69>m]5  
boolean bStop = false; //停止标志 f"OA Zji  
File tmpFile; //文件下载的临时信息 eO[Cb]Dy:  
DataOutputStream output; //输出到文件的输出流 !D|pbzQc8  
6#lC(ko'  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 0wa!pE"  
public SiteFileFetch(SiteInfoBean bean) throws IOException '"G %0y  
{ Ke;X3j ]`  
siteInfoBean = bean; :w&)XI34  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]R3pBC"Jv  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ty,)mx){)  
if(tmpFile.exists ()) GwIfGixqH  
{ 8bKWIN g_n  
bFirst = false; :6Pc m3  
read_nPos(); s poWdRM2  
} TG%hy"k  
else GJl@ag5h]!  
{ PU/Br;2A  
nStartPos = new long[bean.getNSplitter()]; IP4b[|ef  
nEndPos = new long[bean.getNSplitter()]; ^Hhw(@`qf  
} "}~i7NBB  
^J}$y7  
i2%m}S;D9  
cteHuRd  
} _f34p:B%s  
70KXBu<6  
T 6phD8#  
public void run() U*a!Gn7l  
{ aty K^*aX  
//获得文件长度 dc lJ  
//分割文件 NPS=?5p>  
//实例FileSplitterFetch 7 ic]q,  
//启动FileSplitterFetch线程 lbv, jS  
//等待子线程返回 162qxR[.  
try{ |: nuT$(  
if(bFirst) zlFl{t  
{ dYr#  
nFileLength = getFileSize(); rx^pGVyg  
if(nFileLength == -1) c[",WB<9  
{ #c!(97l6o  
System.err.println("File Length is not known!"); u $sX6  
} $X\BO&  
else if(nFileLength == -2) qw_qGgbl  
{ =BGc@:2  
System.err.println("File is not access!"); IFv2S|  
} $ B$=,^)3  
else w"l8M0$m  
{ z*9/"M  
for(int i=0;i<nStartPos.length;i++) E+7S:B  
{ 4AF" +L  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8{d`N|k  
} 8-SVgo(  
for(int i=0;i<nEndPos.length-1;i++) 1eb1Lvn  
{ uHf~KYL  
nEndPos = nStartPos[i+1]; p.l]% \QI  
} _k j51=  
nEndPos[nEndPos.length-1] = nFileLength; crhck'?0  
} YDQV,`S7  
} {1SxM /  
Bj]0Cz  
H=yD}!j  
//启动子线程 2%@j<yS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8D+OF 6CM  
for(int i=0;i<nStartPos.length;i++) gE$dz#t.  
{ pP".?|n  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), h hd n9n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7.=u:PK7kM  
nStartPos,nEndPos,i); Na`qAj}  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9~4Kbmr>q  
fileSplitterFetch.start(); =DqGm]tA  
} {6KU.'#iF  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \/,SH?>4x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Qr0GxGWU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", sX=!o})0  
nEndPos = " + nFileLength); Vxw?"mhP  
// fileSplitterFetch[nPos.length-1].start(); -&HN h\  
PffwNj/l  
~fgv7=(!  
//等待子线程结束 S-L6KA{  
//int count = 0; {1qEN_ERx  
//是否结束while循环 {jv1hKTa  
boolean breakWhile = false; omY?`(=  
5= F-^  
hR?rZUl2M  
while(!bStop) W]R5\ G*  
{ x~(Ul\EX  
write_nPos(); ,= PDL  
Utility.sleep(500); :b ;5O3:B  
breakWhile = true; } K Ou  
E O}(MXS  
0xjV*0?s  
for(int i=0;i<nStartPos.length;i++) *}0Q S@FN  
{ =CJs&Qa2  
if(!fileSplitterFetch.bDownOver) Le}q>>o;q  
{ Tq?W @DM*  
breakWhile = false; +6>Pp[%  
break; Kp99y  
} ](W #Tj5-  
} "5e]-u'  
if(breakWhile) G/D{K$=t~  
break; x~mXtqg  
`q/y|/v<  
T<ua0;7  
//count++; |g9^]bT  
//if(count>4) >0m-S :lk  
// siteStop(); !7w-?1?D  
} :_^YEm+A  
X31kHK5F_  
SHaZ-d  
System.err.println("文件下载结束!"); ?@u &3/&  
} fHgfI@{=j  
catch(Exception e){e.printStackTrace ();} K;Xn!:) V:  
} QoW3*1o  
1"k +K~:  
fY `A  
//获得文件长度 $~2A o[  
public long getFileSize() Ky=&C8b<  
{ a#{a{>  
int nFileLength = -1; IEA[]eik>  
try{ .!`j3W]  
URL url = new URL(siteInfoBean.getSSiteURL()); 7Jqp2\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XYn$yR\dj  
httpConnection.setRequestProperty("User-Agent","NetFox"); k82'gJ;MC=  
0 Hq$h  
A76=^ iw  
int responseCode=httpConnection.getResponseCode(); *zx;81X=  
if(responseCode>=400) Zw3|HV(so  
{ ;Rt,"W)  
processErrorCode(responseCode); q}8R>`Z{  
return -2; //-2 represent access is error z C``G<TB  
} $L&*0$[]Q  
abK/!m[q  
FYi<+]HZ  
String sHeader; b1^MX).vH  
B>'\g O\2  
Rw7Q[I5z%  
for(int i=1;;i++) vz _U  
{ aJfW75C  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3sL#_@+yz  
//Utility.log(in.readLine()); C{,nDa?|  
sHeader=httpConnection.getHeaderFieldKey(i); ^WRr "3  
if(sHeader!=null) QTDI^ZeuF  
{ c1Hv^*Y  
if(sHeader.equals("Content-Length")) yK{~  
{ }b{N[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .$r(":A#)  
break; m3,v&Z  
}  g6~uf4;  
} 5zU D W?  
else >Qi2;t~G  
break; ;+5eE`]a/L  
} ?>w%Lg{L}  
} YS/DIH{9e  
catch(IOException e){e.printStackTrace ();} dtnAMa5$T  
catch(Exception e){e.printStackTrace ();} Ltu;sw  
@Pa ;h  
S4\T (  
Utility.log(nFileLength); .|rpj&>g  
NQOdgp  
r..Rh9v/=E  
return nFileLength; 8 /\rmf\  
} \_+d*hHF~  
8J@REP4  
OW6i2>Or  
//保存下载信息(文件指针位置) R[9[lQ'vR  
private void write_nPos() 7wZKK0;T  
{ h-6kf:XP%  
try{ Iz  ,C!c  
output = new DataOutputStream(new FileOutputStream(tmpFile)); x&kF;UC  
output.writeInt(nStartPos.length); Er%nSH^"  
for(int i=0;i<nStartPos.length;i++) {>syZZ,h  
{ jirxzj  
// output.writeLong(nPos); ;ASlsUE\)  
output.writeLong(fileSplitterFetch.nStartPos); f>Ij:b`Z2  
output.writeLong(fileSplitterFetch.nEndPos); j]jwQRe  
} =WHdy;  
output.close(); }PoB`H'K5  
} JH2d+8O:qK  
catch(IOException e){e.printStackTrace ();} RU@`+6 j+  
catch(Exception e){e.printStackTrace ();} k3u3X~u  
} @C?RbTHy  
l.FkX  
!x&/M*nBE  
//读取保存的下载信息(文件指针位置) -MeGJX:^I  
private void read_nPos() yV_aza  
{ mhVSZhx|  
try{ N U\B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); C?X^h{T p  
int nCount = input.readInt(); 6=iz@C7r  
nStartPos = new long[nCount]; +1_NB;,e  
nEndPos = new long[nCount]; @/7tN3O  
for(int i=0;i<nStartPos.length;i++)   Lxs  
{ EW|bs#l  
nStartPos = input.readLong(); =M>pL+#  
nEndPos = input.readLong(); `cCsJm$V"  
} e![n$/E3R  
input.close(); E]i3E[T  
} /0@'8f\I  
catch(IOException e){e.printStackTrace ();} `gx_+m^  
catch(Exception e){e.printStackTrace ();} h# B%'9r  
} G D$o |l]\  
7"FsW3an  
DFcgUEq  
private void processErrorCode(int nErrorCode) o^}K]ML!t  
{ I^emH+!MW  
System.err.println("Error Code : " + nErrorCode); u%}zLwMH  
} V+(1U|@~  
%`?IY<  
tDJtsOL  
//停止文件下载 9rf6,hF  
public void siteStop() @ l41'?m  
{ s#hIzt  
bStop = true; ;=fOyg  
for(int i=0;i<nStartPos.length;i++) ]ri5mnB  
fileSplitterFetch.splitterStop(); 0Q`Dp;a5&  
GHWi,' mr  
2<q>]G-nN  
} JZ3CCf  
} W US[hx,  
//负责部分文件的抓取 m<}>'D T  
**FileSplitterFetch.java Tr*3:J }  
*/ U[,."w]T  
package NetFox; 0n<>X&X  
]Dec/Nnj  
C>wOoXjt  
import java.io.*; ^hiIMqY_{`  
import java.net.*; xq$(=WPI  
ZRHK?wg'#  
zZp0g^;.?  
public class FileSplitterFetch extends Thread { Lz6b9W  
![1+=F !  
oN({X/P2j  
String sURL; //File URL =>3wI'I  
long nStartPos; //File Snippet Start Position 1*U)\vK~  
long nEndPos; //File Snippet End Position QiKci%=SX  
int nThreadID; //Thread's ID 8L1 vt Yz  
boolean bDownOver = false; //Downing is over H?oBax:  
boolean bStop = false; //Stop identical 5ir Ffr  
FileAccessI fileAccessI = null; //File Access interface v'RpsCov  
J,(@1R]KF:  
O"^3,-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException A#7/,1h\  
{ 00SYNG!  
this.sURL = sURL; `)~]3zmG  
this.nStartPos = nStart; u:]c  
this.nEndPos = nEnd; w :nYsuF  
nThreadID = id; R`5g#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ms=5*_J2Jk  
} (fA>@5n  
NMs 8^O|0  
\<ko)I#%  
public void run() MpK3+4UMa  
{ )d~{gPr.  
while(nStartPos < nEndPos && !bStop) \+M6R<Qw  
{ ZWmS6?L.  
^/~ZP?%]  
 Zh  
try{ +$}3=n34)  
URL url = new URL(sURL); LUs)"ZAi|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &2,3R}B/  
httpConnection.setRequestProperty("User-Agent","NetFox"); q@Aw]Kh  
String sProperty = "bytes="+nStartPos+"-"; -=cxUDB  
httpConnection.setRequestProperty("RANGE",sProperty); X;bHlA-g  
Utility.log(sProperty); Kpg?' !I  
CM%Rz-c  
9r. h^  
InputStream input = httpConnection.getInputStream(); @ D,]v:  
//logResponseHead(httpConnection); O=[Q >\p  
T>hrKn.!D:  
c>Tf@A og>  
byte[] b = new byte[1024]; ,&~-Sq) ~  
int nRead; hpc&s  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?6W v["%  
{ J`]9 n>G  
nStartPos += fileAccessI.write(b,0,nRead); J@o_-\@  
//if(nThreadID == 1) 8NkyT_\  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J!Q #xs  
} 6:~<L!`&  
S{m:Iij[;  
}a !ny  
Utility.log("Thread " + nThreadID + " is over!"); 0q4P hxR`e  
bDownOver = true; ZO!h!2*  
//nPos = fileAccessI.write (b,0,nRead); BG6.,'~7o  
} ^g |j4N  
catch(Exception e){e.printStackTrace ();} s~QIs  
} 8J#xB  
} ]=o1to-  
~470LgpO1  
?W_8 X2(`  
//打印回应的头信息 1N_T/I8_F  
public void logResponseHead(HttpURLConnection con) H:EK&$sU  
{ Im?/#tX  
for(int i=1;;i++) Egz6rRCvg  
{ $Zr \$z2  
String header=con.getHeaderFieldKey(i); |}2/:f#Iz*  
if(header!=null) ?0'e_s  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); /6rQ.+|).  
Utility.log(header+" : "+con.getHeaderField(header)); >k ==7#P  
else %"cOX  
break; F Uz1P  
} JMk2OK {0  
} ,SPgop'  
V?Q45t Ae  
Nd]RbX  
public void splitterStop() x ;~;Ah.p  
{ zB`J+r;LU  
bStop = true; +PnuWK$  
} Wy\^}  
*o5[P\'6  
(-Q~@Q1  
} w_V A:]j4  
{Mj- $G"  
8bQXC+bK  
/* {\`y)k 7  
**FileAccess.java #eN2{G=4+  
*//文件访问(定位,写) AOkG.u-k  
package NetFox; }z#M!~  
import java.io.*; C:t?HLY)fG  
*P5\T4!+d  
(, ik:j  
public class FileAccessI implements Serializable{ YcV^Fqi!  
*DvX|| `&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 r*8a!jm?  
RandomAccessFile oSavedFile; x4PzP  
long nPos; $a8,C\m e?  
ZXL'R |?  
WVsj  
public FileAccessI() throws IOException XZ{rKf2  
{ vNs`UkA  
this("",0); <KK.f9^o(  
} ?-%(K^y4r  
 r73W. &  
r~JGs?GH  
public FileAccessI(String sName,long nPos) throws IOException n_rpT .[  
{ =-~))!(  
oSavedFile = new RandomAccessFile(sName,"rw"); l53Q"ajG  
this.nPos = nPos; si)>:e  
oSavedFile.seek(nPos); SUIJ{!F/  
} sV-P R]  
>&:}L%  
I^( pZ9  
public synchronized int write(byte[] b,int nStart,int nLen) F-b]>3r  
{ _&\'Va$  
int n = -1; ?%su?L  
try{ UCjx   
oSavedFile.write(b,nStart,nLen); SPRTJdaC9  
n = nLen; K?[Vz[-Fc  
} Hc@_@G  
catch(IOException e) !hM`Oe`S  
{ , `Z4fz:  
e.printStackTrace (); R&6@*Nn  
} )+'=Zvgej=  
t:V._@  
rv(N0p/  
return n; q2J |koT  
} +jZa A/  
R4VX*qkB  
'I+M*Iy  
} +ctU7 rVy  
gm,AH85  
~XP|dn}  
/* nyqX\m-  
**SiteInfoBean.java 0SWqC@AR%  
*/ *xpn-hCp<  
package NetFox; MZX)znO  
.%7Le|Fb"  
; U7P{e05  
public class SiteInfoBean { T?f{.a)  
Xe_djy'8  
f OR9N/  
private String sSiteURL; //Site's URL gJuK%P  
private String sFilePath; //Saved File's Path T30fp  
private String sFileName; //Saved File's Name "= %"@"<)  
private int nSplitter; //Count of Splited Downloading File M^8zqAA  
|>xuH#Q  
"0Z /|&  
public SiteInfoBean() E9I08AODS  
{//nSplitter的缺省值为5 Ns1n|^9  
//default value of nSplitter is 5 0M&n3s{5I  
this("","","",5); f42F@M(:  
} HBvyX`-  
Z}0xK6  
c%hXj#;  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) R31Z(vY  
{ M_UmnqN1C  
sSiteURL= sURL; o938!jML_  
sFilePath = sPath; <EgJm`V  
sFileName = sName; "&f|<g5  
this.nSplitter = nSpiltter; ,q#SAZ/N  
WHv6E!^\_  
`5h^!="  
} 0{ B<A^Bf  
%5zIh[!1$  
i}C%8} %  
public String getSSiteURL() wGT>Xh!  
{ b:~#;$g  
return sSiteURL; O.QR1  
} [sk n9$  
Zqe$S +u  
D=3Z] 'A  
public void setSSiteURL(String value) F."ZCEb  
{ tw<Oy^ i  
sSiteURL = value; T6\]*mlr  
} xFThs,w  
^ swj!da  
9)S3{i6w  
public String getSFilePath() W$,/hB& z  
{ 9Xa.%vw>  
return sFilePath; _oG%bNM  
} c u";rnj  
_6h.<BR  
?0KIM* .  
public void setSFilePath(String value) t>N2K-8Qh  
{ G}l9 [lE  
sFilePath = value; zY*~2|q,s  
} $)KODI>|  
XY? Cl  
PIo@B|W-SX  
public String getSFileName() nu1XT 1q1  
{ ']\SX*z?  
return sFileName; T*#M'H7LSQ  
} 4\|Q;@f  
xq,ql@7  
<Rn-B).3bs  
public void setSFileName(String value) Dbi ^%  
{ H}G 9gi  
sFileName = value; O"o|8 l}M/  
} }vY^e OK.  
-u"|{5? '  
#7'k'(  
public int getNSplitter() D~i5E9s5  
{ |X XO0  
return nSplitter; U" 3L  
} XMZ$AeF@  
gSwHPm%zn  
C:^ :^y  
public void setNSplitter(int nCount) [$d]U.  
{ LQ%QFfC  
nSplitter = nCount; k1yqe rA  
} }m^^6h  
} v_U/0 0  
W vu 1?  
( [a$Z2m  
/* VCnf`wZB"  
**Utility.java <zTz/Hk`  
*/ kxEq_FX  
package NetFox; ;3& wO~lW  
`DSFaBj,  
^:ny  
public class Utility { Z{l`X#':  
baTd;`Pn  
kRwY#  
public Utility() GoX<d{  
{ 1uKIO{d @  
$39TP@?:Z)  
*>[ q*SF  
} @m%B>X28F  
V(LfFO{^>?  
//线程睡眠 Y^d#8^cP  
public static void sleep(int nSecond) n.NWS/v_{  
{ Syl9j]  
try{ ABp8PD  
Thread.sleep(nSecond); jG& 8`*|*  
} Jc5Y Gj7  
catch(Exception e) L_:~{jV  
{ "^{Hta  
e.printStackTrace (); 7tJ#0to  
} C-,#t5eir  
} KkzG#'I1  
*'M+oi  
//日志 w&es N$2  
public static void log(String sMsg) mrKIiaU<J  
{ &jg>X+;  
System.err.println(sMsg); 5oB#{h  
} |7Z}#eP//  
wM;=^br  
q`z1ht nf  
public static void log(int sMsg) 9X#]Lg?b  
{ >XuPg(Ow  
System.err.println(sMsg); m`xYd  
} tOk=m'aUK  
} I'n}6D.M  
 =mcQe^M  
"9*MSsU  
/* EUgKJ=jw  
**TestMethod.java /Gb)BJk!  
*/ &h6 `hP_  
package NetFox; UIIsgNca  
B'vIL'  
|vG?H#y  
public class TestMethod { ^ rO}'~(  
R Eo{E  
mQU t 'j4  
public TestMethod() jzi^ OI7  
{ ///xx/weblogic60b2_win.exe ,]9p&xu  
try{ s{Y-Vdx  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); qI74a F  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Lke!VS!P&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); fp3`O9+em  
fileFetch.start(); ose)\rM'  
} :8+x&zn  
catch(Exception e){e.printStackTrace ();} (Nf!E[ }Z  
W ,]Ua]  
s!F8<:FRJD  
} 4~nf~  
Z{F^qwne  
t|UM2h  
public static void main(String[] args) K\lu;   
{ i~4$V  
new TestMethod(); !\Xrl) $j{  
} CX5>/  
} Ycxv=Et  
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