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http断点续传简单实现(java)

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/* i@/%E~W  
**SiteFileFetch.java qZ<n\Mt  
*/ (u?s@/e:`/  
package NetFox; 5H._Q  
import java.io.*; 6C$+D  
import java.net.*; I gJu/{:y^  
{V[xBL <  
|]kiH^Ap  
public class SiteFileFetch extends Thread { W 8<QgpV*  
,.Gp_BI  
ir^d7CV,   
SiteInfoBean siteInfoBean = null; //文件信息Bean h#zm+([B*  
long[] nStartPos; //开始位置 i}T* | P  
long[] nEndPos; //结束位置 5zS%F: 3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 M.g2y&8  
long nFileLength; //文件长度 DS8HSSD  
boolean bFirst = true; //是否第一次取文件 2?,l r2  
boolean bStop = false; //停止标志 dwn|1%D  
File tmpFile; //文件下载的临时信息 8i6iynR  
DataOutputStream output; //输出到文件的输出流 q;SD+%tI  
t_/qd9Jv  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) o9sQ!gptw  
public SiteFileFetch(SiteInfoBean bean) throws IOException wo9R :kQ  
{ 3r%v@8)!b  
siteInfoBean = bean; 9No6\{[M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 6F^/k,(k4  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l"8g9z  
if(tmpFile.exists ()) 8 8u[s@  
{ thPAD+u.3  
bFirst = false; %Vo'\|  
read_nPos(); 9ERdjS  
} 5T/+pC$e=  
else {Lju7'5L  
{ 3\2&?VAjR  
nStartPos = new long[bean.getNSplitter()]; >(:3H+  
nEndPos = new long[bean.getNSplitter()]; z{R Mb  
} ejg!1*H@n  
J#d,?  
0,0WdJAe  
y1`%3\  
} T3b0"o27  
 3B#fnj  
9Zx| L/\  
public void run() A7QT4h&6  
{ 1dr g5  
//获得文件长度 K`=U5vG^  
//分割文件 xgOt%7sb  
//实例FileSplitterFetch "4XjABJ4'  
//启动FileSplitterFetch线程 !@V]H  
//等待子线程返回 s\'t=}0q  
try{ 41R~.?  
if(bFirst) qA}l[:F+#  
{ :MDFTw~|  
nFileLength = getFileSize(); w[2E:Nj  
if(nFileLength == -1) FUI/ A >  
{ Q8TR@0d  
System.err.println("File Length is not known!"); .t ^1e  
} Fkv284,LM  
else if(nFileLength == -2) W&A^.% 2l  
{ + fvVora  
System.err.println("File is not access!"); S?DMeZ{:  
} pDC`Fi  
else i{g~u<DH)Q  
{ oKRI2ni$j9  
for(int i=0;i<nStartPos.length;i++) k8Dk;N  
{ xqT} 9,  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b#709VHm  
} w_@6!zm  
for(int i=0;i<nEndPos.length-1;i++) "+Ks#  
{ M!G/5:VZ  
nEndPos = nStartPos[i+1]; *"|f!t  
} Z'AjeZyyE  
nEndPos[nEndPos.length-1] = nFileLength; ~Q- /O~  
} i&HU7mP/  
} W__$ i<1  
B"7~[,he  
a#0*#&?7@  
//启动子线程 &w_8E+Y Z  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; y=GDuU%  
for(int i=0;i<nStartPos.length;i++) y]Q/(O  
{ D$hK  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 0Dd8c \J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), s$^ 2Cuhv  
nStartPos,nEndPos,i); b#(QZ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <{V{2V#  
fileSplitterFetch.start(); _)CCD33$  
} 45+kwo0  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MNfc1I_#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); g6q[ I8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", T5[(vTp  
nEndPos = " + nFileLength); j%!xb><  
// fileSplitterFetch[nPos.length-1].start(); s_u! RrC  
0s4]eEXH  
gYL#} )g  
//等待子线程结束 &S^a_L:  
//int count = 0; H8c -/  
//是否结束while循环 y_IF{%i  
boolean breakWhile = false; BQMo*I>I  
q|.0Ja  
h#h)=;  
while(!bStop) ud(w0eX  
{ enMHKN g  
write_nPos(); wh]v{Fi'  
Utility.sleep(500); <.|]%7  
breakWhile = true; -P]onD  
O|;|7fCB\  
T.!.3B$@]  
for(int i=0;i<nStartPos.length;i++) :2L-Nf  
{ 7r3EMX\#Qm  
if(!fileSplitterFetch.bDownOver) <l)I% 1T_c  
{ "jq F  
breakWhile = false; >+BLD  
break; Kn+B):OY+  
} Xp^71A?>  
} btf]~YN  
if(breakWhile) bmC{d  
break; l%cE o`U  
yV@~B;eW0  
r2;+ACwWf_  
//count++; ;>p{|^X0D  
//if(count>4) uoY]@.  
// siteStop(); U_0"1+jbq  
} Yv;iduc('  
6r5<uZ9w_X  
&-.2P!t  
System.err.println("文件下载结束!"); -1F+,+m  
} 9(9\kQj{C  
catch(Exception e){e.printStackTrace ();} 7baQ4QY?n  
} y#{> tC  
&W y9%  
2)`4(38  
//获得文件长度 l;JB;0<s"  
public long getFileSize() "CQ:<$|$  
{ 3}?]G8iL?L  
int nFileLength = -1; ue6&)7:~  
try{ C'z}jM`g  
URL url = new URL(siteInfoBean.getSSiteURL()); gDsb~>rb|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); sU?%"q  
httpConnection.setRequestProperty("User-Agent","NetFox"); nrZZkQNI  
vB/G#\Zqz  
~p/1 9/  
int responseCode=httpConnection.getResponseCode(); 4q^'MZm1  
if(responseCode>=400) i\k>2df  
{ )6-!,D0db  
processErrorCode(responseCode); }W"/h)q  
return -2; //-2 represent access is error ]OA8H[U-eA  
} [RUYH5>Ik  
uHO>FM,  
&p^8zEs  
String sHeader; .\ces2,  
@X>Oj.  
 Hn,;G`{  
for(int i=1;;i++) ^&8xfI6?  
{ w`K=J!5y2g  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (f t$ R?  
//Utility.log(in.readLine()); [,ns/*f3R  
sHeader=httpConnection.getHeaderFieldKey(i); w>gB&59r  
if(sHeader!=null) G8p6p6*  
{ f>_' ]eM%  
if(sHeader.equals("Content-Length")) Y]{~ogsn$:  
{ 1lQO`CmR6M  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \ssqIRk  
break; KP]{=~(  
} 2~*.X^dR  
} S_56!  
else B=+Py%  
break; _ye74$#  
} >a2i%j/T  
} Sy`7})[  
catch(IOException e){e.printStackTrace ();} 5"9!kZ(<  
catch(Exception e){e.printStackTrace ();}  [E|%  
iwnFCZVS  
rXu^]CK *G  
Utility.log(nFileLength); t5WW3$Nf  
6{PlclI !  
qm=N@@R&  
return nFileLength; EAXbbcV  
} 1$ C\ `  
\B~}s}  
Qc]Ki3ls  
//保存下载信息(文件指针位置) 6` @4i'.  
private void write_nPos() m'.y,@^B  
{ z#elwL6  
try{ i"o %Gc  
output = new DataOutputStream(new FileOutputStream(tmpFile)); &ywU^hBh  
output.writeInt(nStartPos.length); =5m~rJ< {  
for(int i=0;i<nStartPos.length;i++) uMe]].04  
{ i_6 Y6  
// output.writeLong(nPos); o& "nF+,  
output.writeLong(fileSplitterFetch.nStartPos); aoVfvz2Y  
output.writeLong(fileSplitterFetch.nEndPos); ?#P@N4Uw}y  
} g/6>>p`J  
output.close(); =Hwlo!  
} `z{sDe;  
catch(IOException e){e.printStackTrace ();} '&hk?  
catch(Exception e){e.printStackTrace ();} 3=~0m  
} 8%D 2G i  
{:0TiOP5x  
NvqIYW  
//读取保存的下载信息(文件指针位置) \_J;i[  
private void read_nPos() a8laP N  
{ ~*Kk+w9H<  
try{ ;HbAk`\1A  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ^6(Nu|6\@  
int nCount = input.readInt(); ?m>!P@ M  
nStartPos = new long[nCount]; [=q&5'FY0  
nEndPos = new long[nCount]; ^J-\s_)"  
for(int i=0;i<nStartPos.length;i++) SV0h'd(b  
{ B78e*nNS#2  
nStartPos = input.readLong(); _)? 59  
nEndPos = input.readLong(); n6]8W^g  
} %RS8zN  
input.close(); =7212('F  
} HSsG0&'-Y  
catch(IOException e){e.printStackTrace ();} p`-Oz]  
catch(Exception e){e.printStackTrace ();} ic(`Ev  
} J-wF2*0r<  
sbi+o,%1  
u#"L gG.X  
private void processErrorCode(int nErrorCode) !m<v@SmL\  
{ xaG( 3  
System.err.println("Error Code : " + nErrorCode); \T]'d@Wyd  
} p,K]`pt=  
Q=~ *oYR  
L|H:&|F  
//停止文件下载 dF<GuS;l5  
public void siteStop() 6./3w&D;  
{ Hlj_oDL  
bStop = true; lOuO~`,J  
for(int i=0;i<nStartPos.length;i++) kMP3PS  
fileSplitterFetch.splitterStop(); Mo~zq.  
LW '3m5  
VW/ICX~"d  
} &K.js  
} \7U'p:h=U  
//负责部分文件的抓取 %!r@l7<  
**FileSplitterFetch.java U8gf_R'  
*/ ?6T\uzL +%  
package NetFox; g#/"3P2 H  
rCp'O\@S  
dFVx*{6  
import java.io.*; &;wNJ)Uc  
import java.net.*; _aj,tz  
yT<,0~F9  
$WS?/H0C  
public class FileSplitterFetch extends Thread { P")1_!  
|.EC>D /  
&kp`1kv":  
String sURL; //File URL jC}2>_#m(  
long nStartPos; //File Snippet Start Position 1HS43!  
long nEndPos; //File Snippet End Position @&xWd{8'  
int nThreadID; //Thread's ID sm?V%NX&  
boolean bDownOver = false; //Downing is over QDdH5EfY  
boolean bStop = false; //Stop identical gql^Inx<  
FileAccessI fileAccessI = null; //File Access interface x^]J^L45  
d$T856  
3F ]30  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 2{;~Bg d  
{ s5cY>  
this.sURL = sURL; %;MM+xVVX  
this.nStartPos = nStart; NA;OT7X[  
this.nEndPos = nEnd; SW WeN#Q  
nThreadID = id; w1J%%//(h  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ~,O&A B  
} V+Y;  
%-J} m  
;:A/WU.^  
public void run() !<#,M9 EA&  
{ .TpM3b#r  
while(nStartPos < nEndPos && !bStop) /=IBK`  
{ &~{0@/  
IJ E{JH  
yYN_]& ag  
try{ fuao*L]  
URL url = new URL(sURL); N,ysv/zq7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Nm4 h  
httpConnection.setRequestProperty("User-Agent","NetFox"); /|#";QsPN  
String sProperty = "bytes="+nStartPos+"-"; }$X/HK  
httpConnection.setRequestProperty("RANGE",sProperty); ]b'" l  
Utility.log(sProperty); P?/Mrz   
#L`'<ge'g*  
P5Is#7udN8  
InputStream input = httpConnection.getInputStream(); m4~>n(  
//logResponseHead(httpConnection); u#Y#,:{  
n>k1 D  
` ),ACkU>U  
byte[] b = new byte[1024]; _Qd C V`  
int nRead; &Fy})/F3v  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 6O\a\z  
{ h"ZR`?h  
nStartPos += fileAccessI.write(b,0,nRead); L)yc_ d5  
//if(nThreadID == 1) !}I+)@~\w  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ={[9kR i  
} Ce`#J6lT  
#Pr w2u  
V<ExR@|}.%  
Utility.log("Thread " + nThreadID + " is over!"); Gk-49|qIV  
bDownOver = true; VbfTdRD-  
//nPos = fileAccessI.write (b,0,nRead); hA:RVeS{  
} O0RV>Ml'&  
catch(Exception e){e.printStackTrace ();} .{,fb  
} ,0\P r  
} 4D=^24f`0  
ni~1)"U.  
/ht-]Js$G  
//打印回应的头信息 *Eg[@5;QA  
public void logResponseHead(HttpURLConnection con) _MxKfah'  
{ B:rzM:BQ  
for(int i=1;;i++) Scd_tw.]|  
{ F~;UD<<"H  
String header=con.getHeaderFieldKey(i); ":W$$w<  
if(header!=null) x.kIzI5  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); d<_#Q7]I4  
Utility.log(header+" : "+con.getHeaderField(header)); LVe[N-K  
else JxmFUheLt  
break; "(+p1  
} IrMxdF~c  
} m TgsvC  
/7LAd_P6  
$iMbtA5a Q  
public void splitterStop() xua E\*m  
{ U^ ;H{S  
bStop = true; gn)>(MG  
} aW*8t'm;m'  
{n 4W3  
^E]y >Y  
} ;/ASl<t,  
OOZxs?pR  
s_#6^_  
/* a?1Ml>R6P  
**FileAccess.java > JP}OS  
*//文件访问(定位,写) pKkBA r,  
package NetFox; HApjXv!U[  
import java.io.*; 5ggsOqH  
U#g ,XJ  
9CPr/q9'  
public class FileAccessI implements Serializable{ QE4TvnhK  
)QAS7w#k  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 l|sC\;S  
RandomAccessFile oSavedFile; RN"Ur'+  
long nPos; (-%1z_@Y  
d^qTY?k.  
p(fL' J  
public FileAccessI() throws IOException  Uu0  
{ t{Wu5<F:  
this("",0); )NmYgd~%  
} `h='FJ/!  
;.{J>Q/U,  
pSdtAv  
public FileAccessI(String sName,long nPos) throws IOException H:]'r5sw  
{ Wa<SYJ  
oSavedFile = new RandomAccessFile(sName,"rw"); $ #bWh  
this.nPos = nPos; M$Ow*!DfP  
oSavedFile.seek(nPos); .f-s+J&ED  
} }9~U5UXWU  
c1ptN  
L "5;<  
public synchronized int write(byte[] b,int nStart,int nLen) M,dp;  
{ g=e~YM85  
int n = -1; e'T|5I0K  
try{ (w1$m8`=  
oSavedFile.write(b,nStart,nLen); s(pNg?R  
n = nLen; d8J(~$tXQN  
} n+D93d9LP  
catch(IOException e) [! Zyp`:  
{ !`0 El',gY  
e.printStackTrace (); 9w.ZXd  
} Q?V'3ZZF!  
tqXCj}mR  
>~*}9y0$  
return n; v~:'t\n  
} j2s{rQQ  
eOZ"kw"uHu  
GQ6~Si2  
} #'8'5b  
,m[#<}xXA  
0aa&13!5  
/* NeR1}W  
**SiteInfoBean.java hxkwT  
*/ _18Aek   
package NetFox; $f AZ^   
?X@uR5?{  
k-I U}|Xz  
public class SiteInfoBean { \[<8AV"E-'  
n'8 3P%x  
`{H!V~42  
private String sSiteURL; //Site's URL Ntlbn&lc;D  
private String sFilePath; //Saved File's Path i|!W;2KL5  
private String sFileName; //Saved File's Name qlC4&82=Q  
private int nSplitter; //Count of Splited Downloading File .o)  
S z-TarTF  
D-Q54"^3  
public SiteInfoBean() q.ZkQN+  
{//nSplitter的缺省值为5 O|0V mm  
//default value of nSplitter is 5 6+/BYN!&4  
this("","","",5); 4VP$, |a  
} .5!Q(  
FW:V<{f  
#{5h6IC  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) o!zo%#0;#)  
{ qPn!.m$/  
sSiteURL= sURL; Lklb  
sFilePath = sPath; B pp(5  
sFileName = sName; WDF6.i ?  
this.nSplitter = nSpiltter; J<MuWgx&  
!SThK8j$7  
$|VD+[jSV  
} '5\?l:z  
eA-$TSWh  
o,!W,sx_  
public String getSSiteURL() En ]"^*  
{ j`QXl  
return sSiteURL;  Sr+ &  
} %Mf3OtPiJW  
TNlS2b1  
~|&To >  
public void setSSiteURL(String value) ] uXmug  
{ wDKA1i%G  
sSiteURL = value;  h 3V; J  
} >S@><[C  
)<`/Aaie  
BHR(B]EI  
public String getSFilePath() e#^ vA$d  
{ wUH:l  
return sFilePath; @6V kNe9  
} X4/3vY  
Kza5_ 7p`L  
%";ap8J04F  
public void setSFilePath(String value) +<'>~lDg  
{ h y"=)n(  
sFilePath = value; `gdk,L]  
} v,c;dlg_  
}i52MI1-XP  
*R8P brN  
public String getSFileName() +oiuulA  
{ R]N"P:wf@  
return sFileName; Lv@'v4.({  
} {; 3a^K  
4YA1~7R  
!-tVt D  
public void setSFileName(String value) M<ba+Qn$  
{ ?GGBDql  
sFileName = value; .=@CF8ArG  
} &Y-jK<  
*a'I  
G!U `8R  
public int getNSplitter() M<xF4L3]  
{ =z#j9'n$@  
return nSplitter; g3c,x kaO  
} Z@bKYfGM  
`86})xz{  
wj\kx\+  
public void setNSplitter(int nCount) @VnK/5opS  
{ rhC x&L  
nSplitter = nCount; 2[1lwV  
} 35Fs/Gf-n  
} >+Y@rj2  
RC^k#+  
d+]/0J!c  
/* _FzAf5DO  
**Utility.java \1oN't.  
*/ O[ug7\cl+  
package NetFox; mBDzc(_\$'  
s$xm  
?{r-z3@ N  
public class Utility { 5$c*r$t_RK  
]f*.C9Y  
3u4P [   
public Utility() bE b+oRI  
{ v|:TYpku3  
nw=:+?  
ZX0!BS  
} du&9mOrr  
6,(S}x YDZ  
//线程睡眠 R!2E`^{Wl  
public static void sleep(int nSecond) vpoJ{TPO  
{ 14yzGhA  
try{ {$'oKJy*  
Thread.sleep(nSecond); dyt.( 2  
} )pw53,7>aN  
catch(Exception e) uwu`ms7z 2  
{ `}#n#C)  
e.printStackTrace (); }h=3[pe}  
} 4x_# 1 -  
} u=ZZ;%Rvd  
]Mj N)%hT  
//日志 URMxCL^"  
public static void log(String sMsg) >uJU25)|  
{ W@61rT} c  
System.err.println(sMsg); #g]eDU-[  
} hv)d  
mf\@vI  
] jycg@=B  
public static void log(int sMsg) vzZ"TSP  
{ 6IKi*}  
System.err.println(sMsg); I~25}(IDZ"  
} ]_2<uK}fg  
} r-5xo.J'  
_Q}vPSJviC  
sLW e \o  
/* _q`f5*Z[  
**TestMethod.java >H,PST  
*/ *[tLwl.  
package NetFox; Q=#Wk$1.  
*zWf8X  
A&:~dZ:%w  
public class TestMethod { V0y_c^x  
x_#'6H\1ga  
bOK0^$k  
public TestMethod() 5/i]Jni  
{ ///xx/weblogic60b2_win.exe .>@]Im  
try{ xi=Qxgx0I  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); :{~TG]4M  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); <ugy-vSv  
SiteFileFetch fileFetch = new SiteFileFetch(bean); tFX!s;N[  
fileFetch.start(); WP4 "$W  
} ,pa=OF  
catch(Exception e){e.printStackTrace ();} lfte   
@O)1Hnm  
TFtD>q X  
} R^Y _i  
|4F'Zu}g>  
|/;X -+f8  
public static void main(String[] args) "PC9[i  
{ k9iB-=X?4s  
new TestMethod(); }Pj;9ivz  
} &Tk@2<5=  
} @!%HEs!# #  
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