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http断点续传简单实现(java)

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/* EERCb%M 8Z  
**SiteFileFetch.java vmv6y*qU  
*/ iSX HMp4V  
package NetFox; X(O:y^sX}  
import java.io.*; .}GOHW)}  
import java.net.*; *0vRVlYf  
KRX\<@  
!3<b#QAXRG  
public class SiteFileFetch extends Thread { p1[|5r5Day  
Z`f?7/"B  
1g,Ofr  
SiteInfoBean siteInfoBean = null; //文件信息Bean B}P!WRNmln  
long[] nStartPos; //开始位置 1Vkb}A,'  
long[] nEndPos; //结束位置 [wk1p-hf  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 x:i,l:x  
long nFileLength; //文件长度 V["'eJA,,  
boolean bFirst = true; //是否第一次取文件 qu.AJ*  
boolean bStop = false; //停止标志 M+M  ;@3  
File tmpFile; //文件下载的临时信息 uGn BlR$}  
DataOutputStream output; //输出到文件的输出流 Adet5m.|[8  
<I*N=;7  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) g\9&L/xDN  
public SiteFileFetch(SiteInfoBean bean) throws IOException m7`S@qG  
{ )6BySk  
siteInfoBean = bean; Lxn-M5RPQ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); (/^?$~m"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); S'`G7ht  
if(tmpFile.exists ()) |'lNR)5  
{ -aLM*nIoe  
bFirst = false; fu{v(^  
read_nPos(); vM-kk:n7f  
} y<*\D_J  
else A8QUfg@uK~  
{ [0 rH/{  
nStartPos = new long[bean.getNSplitter()]; O 3?^P"C  
nEndPos = new long[bean.getNSplitter()]; Rqbz3h~  
} [?=DPE%  
W6`_ lGTj  
A~ v[6*~>  
&G[W$2`@  
} f'MRC \  
Lp3pJE  
MR: H3  
public void run()  )y6  
{ }O+S}Hbwy  
//获得文件长度 :#\jx  
//分割文件 ]<ay_w;  
//实例FileSplitterFetch I?nU+t;  
//启动FileSplitterFetch线程 6kMEm)YjT  
//等待子线程返回 -7XaS&.4  
try{ ,S m?2<  
if(bFirst) _dECAk &b  
{ |9F-ZH~6  
nFileLength = getFileSize(); ZFh[xg'0  
if(nFileLength == -1) BpGyjo J2  
{ >l=jJTJ;q  
System.err.println("File Length is not known!"); V3T.EW  
} h#Mx(q  
else if(nFileLength == -2) C?MKb D=K  
{ zlB[Eg^X  
System.err.println("File is not access!"); v9!] /]U^  
} *>!-t   
else 8Ht=B,7T  
{ J*zQ8\f=}  
for(int i=0;i<nStartPos.length;i++) uhv_'Q  
{ *3h_'3yo@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0C3Y =F  
} gv&Hu$ ca  
for(int i=0;i<nEndPos.length-1;i++) )Jw$&%/{1  
{ Y9 Bk$$#\  
nEndPos = nStartPos[i+1]; xT( pB-R  
} /XA*:8~!  
nEndPos[nEndPos.length-1] = nFileLength; 9xK#( M  
} bdvpH DA  
} WRRR"Q$  
!b+!] 2~g}  
P(o>UDy  
//启动子线程 t8;nP[`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; rWqr-"0S.  
for(int i=0;i<nStartPos.length;i++) Z#l6BXK  
{ .Iz JJp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (LMT'   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 4N1)+ W8k*  
nStartPos,nEndPos,i); qVO,sKQ{  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ef@)y&hn  
fileSplitterFetch.start(); iA`.y9'2  
} 2f{a||  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KxBvL[/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); xX0 wn?,~  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", {iCX?Sb  
nEndPos = " + nFileLength); sk_xQo#Y 3  
// fileSplitterFetch[nPos.length-1].start(); gxJ12' m  
h`eHoKJ#w  
h Fan$W$  
//等待子线程结束 '*Tt$0#o  
//int count = 0; kIe)ocJg  
//是否结束while循环 qv >l  
boolean breakWhile = false; Y4lNxvY  
|VjD. ]I  
5/T#>l<  
while(!bStop) h Z/p'  
{ % .ss  
write_nPos(); '|*e4n  
Utility.sleep(500); C[l5[DpH  
breakWhile = true; J l{My^I5  
e2>AL  
hSN38wy  
for(int i=0;i<nStartPos.length;i++) ><. *5q  
{ )nq(XM7  
if(!fileSplitterFetch.bDownOver) :22wq{  
{ %h;1}SFl0  
breakWhile = false; TTWiwPo59  
break; b/\l\\$-  
} 3<[q>7X  
} }AiF 7N0  
if(breakWhile) 'geN  dx  
break; / %F,  
c+O:n:L  
m;TekJXm  
//count++; W&[-QM8  
//if(count>4) 5{IbKj|  
// siteStop(); RSw; b.t7  
} 7osHKO<?2  
K(?p]wh  
M"msLz  
System.err.println("文件下载结束!"); @3U=kO(^+\  
} ?k@;,l :s  
catch(Exception e){e.printStackTrace ();} MX+gc$Y O  
} ?(}~[  
h&!$ `)   
Z Y5Pf 1  
//获得文件长度 !t{  
public long getFileSize() JW=q'ibR  
{ pX$ X8z%  
int nFileLength = -1; F}@]Lq+  
try{ ,% .)mf  
URL url = new URL(siteInfoBean.getSSiteURL()); v`Ja Bn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^X"x,8}&V  
httpConnection.setRequestProperty("User-Agent","NetFox"); A!uiM*"W  
Jp_ :.4  
r Cz,XYV  
int responseCode=httpConnection.getResponseCode(); tWQ$`<h  
if(responseCode>=400) Qw"%Xk  
{ (.wR!l# !  
processErrorCode(responseCode); 10GU2a$0"$  
return -2; //-2 represent access is error =.) :tGDp  
} }^b  
RXu` DWN  
9C!b f \  
String sHeader; ?+%bEZ`  
N| P?!G-=  
V?jWp$  
for(int i=1;;i++) #/_ VY.  
{ pwB>$7(_h  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); r]aI=w<(f  
//Utility.log(in.readLine()); WD*z..`  
sHeader=httpConnection.getHeaderFieldKey(i); WY5HmNX3E  
if(sHeader!=null) NQcg}y  
{ uU-1;m#N?  
if(sHeader.equals("Content-Length")) afu!.}4Ct  
{ ,Vof<,x0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); '!`]Zc  
break; qd~9uo&[Ig  
} EN8xn9M?  
} m,}GP^<1i  
else U]9k,#  
break; 8KKhD$  
} k 6i&NG6  
} KYl!Iw67d  
catch(IOException e){e.printStackTrace ();} [8Z !dj   
catch(Exception e){e.printStackTrace ();} Ht]O:io`  
5v=e(Ph +  
[F{P0({%?  
Utility.log(nFileLength); e nw*[D !  
g+(Y)9h&  
&^Gp  
return nFileLength; C<w&mFozL  
} cJM.Q_I}Y  
mHH>qW{`  
.*J /F$  
//保存下载信息(文件指针位置) PR,8c  
private void write_nPos() VtGZB3  
{ _?eT[!oO8  
try{ aB`jFp-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); T#[#w*w/  
output.writeInt(nStartPos.length); R D?52\  
for(int i=0;i<nStartPos.length;i++)  NfmHa  
{ $s 'n]]Wq  
// output.writeLong(nPos); g8" H{u  
output.writeLong(fileSplitterFetch.nStartPos); JBLh4c3  
output.writeLong(fileSplitterFetch.nEndPos); C 5e;U  
} 7*He 8G[W  
output.close(); =j{Kxnv  
} 3~Ap1_9  
catch(IOException e){e.printStackTrace ();} ["<'fq;PJ  
catch(Exception e){e.printStackTrace ();} #%V+- b(  
} )HX(-"c  
Y.#fpG'  
LyL(~Jc|  
//读取保存的下载信息(文件指针位置) ktp<o.f[  
private void read_nPos() 8PWEQ<ev7>  
{ HK%W7i/k@  
try{ j[dgY1yE:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); NYzBfL x  
int nCount = input.readInt(); VSh&Y_%  
nStartPos = new long[nCount]; Nu'ox. V  
nEndPos = new long[nCount]; p\.IP2+c  
for(int i=0;i<nStartPos.length;i++) QFgKEUNgl  
{ 1y,/|Y  
nStartPos = input.readLong(); .8;0O M  
nEndPos = input.readLong(); "^Y zHq6  
} r @ !  
input.close(); H?V b   
} 6)>otB8)J  
catch(IOException e){e.printStackTrace ();} ofPv?_@  
catch(Exception e){e.printStackTrace ();} wrsr U  
} JC;&]S.  
!%.=35NS@E  
OB*V4Yv  
private void processErrorCode(int nErrorCode) {<?8Y  
{ .N`*jT  
System.err.println("Error Code : " + nErrorCode); yT~x7,  
} ExeZj8U  
E=`/}2  
c5: X$k\  
//停止文件下载 9PMIF9"   
public void siteStop() |--Jd$ dj  
{ qwO@>wQ}~  
bStop = true; N,3iSH=cN[  
for(int i=0;i<nStartPos.length;i++) cv7:5P  
fileSplitterFetch.splitterStop(); fPPmUM^C9  
qB&Je$_uh  
dP`B9>r  
} sRqecG(n  
} uL^`uI#I  
//负责部分文件的抓取 7!\zo mx  
**FileSplitterFetch.java |=MhI5gsx  
*/ B-PX/Q  
package NetFox; 5L_`Fw\l  
v G9>e&Be  
7R# }AQ   
import java.io.*; HxcL3Bh$~}  
import java.net.*; `*D"=5G+  
m;t&P58f  
+'nMy"j1  
public class FileSplitterFetch extends Thread { (OA4H1DL^  
)4m`Ya,E3  
d`=LZio  
String sURL; //File URL BRM!g9  
long nStartPos; //File Snippet Start Position 4u"Bll  
long nEndPos; //File Snippet End Position D2=zrU3Y64  
int nThreadID; //Thread's ID b};o:  
boolean bDownOver = false; //Downing is over Rd|8=`)  
boolean bStop = false; //Stop identical OHrzN ']  
FileAccessI fileAccessI = null; //File Access interface z,4 D'F&  
oR/_{#Mz"  
\ Ce*5h  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException )a x>*  
{ /?($W|9+l  
this.sURL = sURL; ;mvVo-r*q  
this.nStartPos = nStart; +.OdrvN4)  
this.nEndPos = nEnd; "?<h,Hvi  
nThreadID = id; c*(^:#"9  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 't5`Ni  
} m^=El7+  
_x|.\j  
3!vzkBr  
public void run() ?~!9\dek,  
{ n?;rWq"  
while(nStartPos < nEndPos && !bStop) xu%eg]  
{  K[LuvS  
)nFyHAy-  
u05Yy&(f  
try{ VxuV`Plf  
URL url = new URL(sURL); $mh\`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _(I6o  
httpConnection.setRequestProperty("User-Agent","NetFox"); =I@I  
String sProperty = "bytes="+nStartPos+"-"; ]V_A4Df  
httpConnection.setRequestProperty("RANGE",sProperty); :2&"ak>N  
Utility.log(sProperty); Z# bO}!  
D W^Zuu/)  
,wXmJ)/WZ  
InputStream input = httpConnection.getInputStream(); :7mHPe }(  
//logResponseHead(httpConnection); 14jN0\  
G$%F`R[  
.Y"F3 R  
byte[] b = new byte[1024]; 32j}ep.*  
int nRead; j@ D,2B;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) C4P<GtR9  
{ 0bT[05.  
nStartPos += fileAccessI.write(b,0,nRead); KIag(!&  
//if(nThreadID == 1) Wpi35JrC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [uLs M<C  
} 4+s6cQ]S`  
RAP-vVh/C  
CxZh^V8LP  
Utility.log("Thread " + nThreadID + " is over!"); l`i97P?/W  
bDownOver = true; B4wRwrVI>  
//nPos = fileAccessI.write (b,0,nRead); [ ~2imS  
} j49Uj}:j  
catch(Exception e){e.printStackTrace ();} $LFL4Q  
} %yu =,J j  
} $Ery&rX.  
ovBmo2W/  
xLDD;Qm,  
//打印回应的头信息 g\ vT7x  
public void logResponseHead(HttpURLConnection con) tiHR&v  
{ q$mc{F($D  
for(int i=1;;i++) upL3M`  
{ I "~.p='  
String header=con.getHeaderFieldKey(i); G3%Ju=  
if(header!=null) _]pu"hZz4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); P(TBFu  
Utility.log(header+" : "+con.getHeaderField(header)); >3Q|k{97  
else aR/?YKA  
break; m<#12#D  
} XW" 0:}`J  
} ]| +M0:2?  
9|#cjHf  
kuV7nsXiQ  
public void splitterStop() ``Q6R2[|)  
{ ;'= cNj  
bStop = true; c$%*p (zY  
} nGkSS_X  
=@?[.`  
%&| uT  
} R]iV;j|  
,1$F #Eh  
z+yIP ?s}(  
/* C?T\5}h  
**FileAccess.java G+t:]\  
*//文件访问(定位,写) eY5mwJ0K  
package NetFox; mV$ebFco0  
import java.io.*; 4n@lrcq(  
m(6d3P  
x9 %=d  
public class FileAccessI implements Serializable{ dQ.#8o=  
%gh#gH   
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 N}K [Q=  
RandomAccessFile oSavedFile; ?YLq iAA  
long nPos; D5D *$IC  
E)gD"^rex  
R=lw}jH[Z  
public FileAccessI() throws IOException ;*M@LP{*L  
{ "J1A9|  
this("",0); a3tcLd|7J  
} 89g a+#7  
JfIXv  
8b)WOr6n  
public FileAccessI(String sName,long nPos) throws IOException At4\D+J{Vs  
{ 1x:W 3.  
oSavedFile = new RandomAccessFile(sName,"rw"); \}s/<Q  
this.nPos = nPos; !i^"3!.l,]  
oSavedFile.seek(nPos); 2Lf,~EV  
} D=TS IJ@  
SG&,o =I$  
ir_XU/ve  
public synchronized int write(byte[] b,int nStart,int nLen) 'bi;Y1:  
{ dm4Q'u  
int n = -1; ` 3qf}=Z`  
try{ <m]0!ii  
oSavedFile.write(b,nStart,nLen); d-D,Gx]>$  
n = nLen; yx :^*/  
} G`Nw]_ Z_  
catch(IOException e) m9DFnk<D  
{ }kqh[`:  
e.printStackTrace (); 3ic /xy;}  
} >8e)V ;  
Mw/9DrE7/  
nn_O"fZi  
return n; ]?tRO  
} =9GA LoGL  
Q&eyqk   
o utJ/~9;  
} ?,>3uD#  
lFjz*g2'  
dFy$w=  
/* s5nw<V9$]  
**SiteInfoBean.java \9)5b8  
*/ Hd|[>4Z  
package NetFox; <l{oE? N  
k&ci5MpN  
&zdS9e-fF  
public class SiteInfoBean { ""0 Y^M2I  
Rql/@j`JX  
ga 5Q  
private String sSiteURL; //Site's URL 9\_AB.Z:  
private String sFilePath; //Saved File's Path g"m' C6;  
private String sFileName; //Saved File's Name Zv;nY7B  
private int nSplitter; //Count of Splited Downloading File h;gc5"mG  
{aY) Qv}  
/iU<\+ H  
public SiteInfoBean() TTz=*t+D  
{//nSplitter的缺省值为5 ]y_ :+SHc  
//default value of nSplitter is 5 Z-PB CU  
this("","","",5); A@}5'LzL  
} J\L'HIs  
Vp/XVyL}R  
WHdMP  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) EZ)b E9  
{ An. A1y  
sSiteURL= sURL; xE:jcA d$}  
sFilePath = sPath; 1=R$ RI  
sFileName = sName; ^k=<+*9  
this.nSplitter = nSpiltter; o$*(N  
<fvu) f  
Nw*<e ]uD  
} FEjO}lTK  
*7xcwj eP  
oy^-?+   
public String getSSiteURL() $hhXsu=  
{ 0cS$S Mn{  
return sSiteURL; U>2KjZB  
} 9 C[~*,qx  
(U:-z=E#1  
c RLw)"|  
public void setSSiteURL(String value) ,HZ%q]*:~  
{ |?T=4~b  
sSiteURL = value; ihrf/b  
} fDy*dp4z  
^4n#''wJ  
U@OdQAX  
public String getSFilePath() QLY;@-jF$  
{ Msqqjhoy  
return sFilePath; 9\Jc7[b  
} ]-\68bN  
4z<c8 E8  
xMjhC;i{  
public void setSFilePath(String value) <_Yd N)x  
{ u7< +)6-  
sFilePath = value; D$}hoM1  
} X30tO>  
}~ D WB"  
qp})4XTv  
public String getSFileName() Wk%|%/:  
{ I3Vu/&8f|  
return sFileName; %1i:*~g  
} ojM'8z 0Hn  
32ki ?\P  
^~~Rto)Y  
public void setSFileName(String value) wA5Iz{uQO  
{ w-K A~  
sFileName = value; *tqD:hiF  
} [7I:Dm  
d A)T>  
jFN0xGZ  
public int getNSplitter() +#Pb@^6"m  
{ ##jJa SxG  
return nSplitter; k{qxsNM  
} ,Cr%2Wg-  
&>jz[3  
Q!l(2nva  
public void setNSplitter(int nCount) Y$JVxly  
{ 8_%GH}{  
nSplitter = nCount; AG,><UP  
} F$t]JM  
} q;e b  
@[r[l#4yUi  
kLgkUck8]  
/* T?1BcY  
**Utility.java c(Dp`f,  
*/ n #X~"|U`  
package NetFox; wkp2A18n  
U"Gx Xrl  
qyRN0ZB"A^  
public class Utility { yj:@Fg-3g  
BM!ZdoKrKt  
Y<T0yl?  
public Utility() </25J((  
{ :E")Zw&sW3  
vkG#G]Qs";  
SJiQg-+<Uf  
} rj=as>6B  
c,1  G+.  
//线程睡眠 }b2YX+/e$f  
public static void sleep(int nSecond) 0nt@}\j  
{ dj0%?g>  
try{ 9`f@"%h  
Thread.sleep(nSecond); $FPq8$V  
} (.#nl}fA  
catch(Exception e) X_78;T)uA  
{ J 1w[gf]J  
e.printStackTrace (); YoKE=ln7  
} i9ySD  
} B#g~c<4<  
0qN`-0Yk  
//日志 _mm(W=KiL  
public static void log(String sMsg) Q/|.=:~FO  
{ yr%[IX]R  
System.err.println(sMsg); .)/ ."V  
} m7k }k)  
fqI67E$59  
MFq?mZ,  
public static void log(int sMsg) aU6l>G`w  
{ ]wid;<  
System.err.println(sMsg); kZ5#a)U<  
} f#ZM 2!^!  
} ZUS-4'"$  
O i\ s  
/si<Fp)z  
/* #Vum  
**TestMethod.java utmJ>GWSI  
*/ GFFwk4n1  
package NetFox; 7^i7U-A<A  
'HW l_M  
cX9o'e:C  
public class TestMethod { Tx} Nr^   
JMB#KzvN[  
XZ%[;[  
public TestMethod() icb)JZ1K  
{ ///xx/weblogic60b2_win.exe 4M&$wi  
try{ a#]V|1*O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); RI*n]HNgy+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); =AO (  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]njNSn  
fileFetch.start(); r|l?2 eO~  
} (?l ]}p^[  
catch(Exception e){e.printStackTrace ();} X$@`4  
LcGKYl(\K  
I0x)d`  
} ,yC..aI  
K<^p~'f4P  
g>t1rZ  
public static void main(String[] args) bll[E}E|3  
{ *)RKU),3nL  
new TestMethod(); :6Z2@9.}w  
} +6uf6&.@~  
} )h@PRDI_  
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