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http断点续传简单实现(java)

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/* [ENm(e$sI  
**SiteFileFetch.java SAt{At  
*/ S& % G B  
package NetFox; VSCOuNSc  
import java.io.*; nTweQ  
import java.net.*; &JM|u ww?1  
LuB-9[^<  
/,z4tf  
public class SiteFileFetch extends Thread { <$LVAy"RD  
61q:nWs  
g jJ?*N[  
SiteInfoBean siteInfoBean = null; //文件信息Bean <3iL5}  
long[] nStartPos; //开始位置 u+GtH;<;  
long[] nEndPos; //结束位置 ;5A  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 < 6[XE  
long nFileLength; //文件长度 lUd/^u`  
boolean bFirst = true; //是否第一次取文件 u|.L7 3<j%  
boolean bStop = false; //停止标志 wPYz&&W  
File tmpFile; //文件下载的临时信息 lz1l1.f8  
DataOutputStream output; //输出到文件的输出流 `Li3=!V[  
G-[fz  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) S$Tc\ /{  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,25Qhz]  
{ `Pv[A  
siteInfoBean = bean; R g7  O  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); s('<ms  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); cWSiJr):r  
if(tmpFile.exists ()) ]VY}VALZ  
{ : uglv6  
bFirst = false; oX@0+*"  
read_nPos(); 0 V:z(r  
} 'PF?D~  
else eDR4 c%  
{ x8xSA*@k  
nStartPos = new long[bean.getNSplitter()]; ML!Z m[I9  
nEndPos = new long[bean.getNSplitter()]; AXhV#nZt0  
} :4PK4D s7  
< ) L'h  
gN|[n.W4  
A"8` 5qa  
} ,c#=qb8""  
8*;88vW"2  
sG`:mc~0   
public void run() JW;DA E<  
{ ,lLkAd?q  
//获得文件长度 4i>sOP3 B  
//分割文件 K'EGm #I  
//实例FileSplitterFetch )2KQZMtgm]  
//启动FileSplitterFetch线程 BD+V{x}P  
//等待子线程返回 KPI c?|o/6  
try{ z{w!yMp"  
if(bFirst) /l-lkG5  
{ vq|o}6Et  
nFileLength = getFileSize(); T> cvV  
if(nFileLength == -1) 5_@ u Be~  
{ B>}=x4-8  
System.err.println("File Length is not known!"); o qa]iBO  
} E(F<shT#  
else if(nFileLength == -2) LwQq0<v  
{ r]p 0O(  
System.err.println("File is not access!"); (a0q*iC%  
} C~IsYdln  
else  -z9-f\  
{ PMzPe"3M  
for(int i=0;i<nStartPos.length;i++) kGsd3t!'  
{ ,C%fA>?UF8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); hm"i\JZ3N  
} Z<6XB{Nh\  
for(int i=0;i<nEndPos.length-1;i++) 3[plwe  
{ 1'wwwxe7  
nEndPos = nStartPos[i+1]; rcUXYJCh-  
} 5(0f"zY  
nEndPos[nEndPos.length-1] = nFileLength; (he cvJ  
} z yyt`  
} $Cw> z^}u  
!e?g"5r{Bv  
dGf:0xE"  
//启动子线程 x#ub % t  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; iq_y80g`8h  
for(int i=0;i<nStartPos.length;i++) EY=`/~|c  
{ @giJ&3S,  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .:?X<=!S&t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), V3 j1M?>  
nStartPos,nEndPos,i); ns|)VX   
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )&R^J;W$M1  
fileSplitterFetch.start(); ;Z%PBMa  
} \~|+*^e)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qP6 YnJWl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); q 65mR!)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "L'0"  
nEndPos = " + nFileLength); ,f ..46G  
// fileSplitterFetch[nPos.length-1].start(); /,v>w,  
0Q^ -d+!  
YY~BNQn6d  
//等待子线程结束 V7}5Zw1  
//int count = 0; 34ij5bko_)  
//是否结束while循环 Ve,h]/G  
boolean breakWhile = false; +L(0R&C  
i;4|UeUl  
/[Oo*}Dc=F  
while(!bStop) "iFA&$\  
{ jiS|ara"  
write_nPos(); Vsh7>|@  
Utility.sleep(500); s ~'><ioh  
breakWhile = true; H'N$Vv2q  
6[g~p< 8n}  
XRi/O)98o  
for(int i=0;i<nStartPos.length;i++) X2>qx^jT  
{ ?;1^8 c0  
if(!fileSplitterFetch.bDownOver) ;Ml??B]C  
{ l AF/O5b  
breakWhile = false; !Z +4FwF  
break; {k.Dy92  
} >iefEv\  
} 1T(:bM_t`7  
if(breakWhile) 3QlV,)}  
break; xlQl1lOX  
bo^d!/ ;  
}1<_  
//count++; 2,.%]U  
//if(count>4) '\yp}r'u  
// siteStop(); gY'w=(/`  
} VO"f=gFg  
WR'm<u  
r?Y+TtF\e  
System.err.println("文件下载结束!"); uYW9kw>$  
} tEEeek(!  
catch(Exception e){e.printStackTrace ();} 99Jk<x k  
} 4 j9  
uMW5F-~-+  
M XB fX  
//获得文件长度 q^nSYp#  
public long getFileSize() 3fC|}<Wzt  
{ xi5/Wc6  
int nFileLength = -1; WU oGIT'  
try{ /9/svPc]  
URL url = new URL(siteInfoBean.getSSiteURL()); ;DWtCtD  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Yv0;UKd  
httpConnection.setRequestProperty("User-Agent","NetFox"); qkX}pQkG)h  
DtBIDU]  
}q0lbwYlb  
int responseCode=httpConnection.getResponseCode(); f@@2@# 5B  
if(responseCode>=400) B-63IN  
{ n7UZ&ab  
processErrorCode(responseCode); UPtWj8h  
return -2; //-2 represent access is error xgl~4  
} wFr}]<=Mi  
,>-Q#  
Zkn$D:  
String sHeader; ]KX _a1e  
<a>\.d9#)7  
/rRQ*m_  
for(int i=1;;i++) b}P5*}$:9"  
{ -OLXRc=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5fGUJ[F=  
//Utility.log(in.readLine()); \VW&z:/*pZ  
sHeader=httpConnection.getHeaderFieldKey(i); 1iOQ8hD  
if(sHeader!=null) Mp;yvatO  
{ j!c[$;  
if(sHeader.equals("Content-Length")) {4\hxyw  
{ N_jCx*.G  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); r Ntc{{3_  
break; ~i)O^CKq  
} m#[tY >Q[b  
} UloZo? e`  
else ;bJ2miO"e  
break; l@}BWSx&ms  
} !6:q#B*  
} F">>,Oc)U"  
catch(IOException e){e.printStackTrace ();} !A>VzW  
catch(Exception e){e.printStackTrace ();} Y~=]RCg  
[oOA@  
#A|~s;s>N  
Utility.log(nFileLength); j\w>}Pc  
)3i}(h0  
>-0b@ +j  
return nFileLength; I+ipTeB^  
} ,z}wR::%  
o6e6Jw  
$"Oy }  
//保存下载信息(文件指针位置) \R& 4Nu2F  
private void write_nPos() ns.[PJ"8  
{ "P:kZ= M Q  
try{ s^_E'j$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }`/wj  
output.writeInt(nStartPos.length); A[juzOn\  
for(int i=0;i<nStartPos.length;i++) h3^ &,U  
{ Gmcx#?|Tx  
// output.writeLong(nPos); Is6<3eQ\x  
output.writeLong(fileSplitterFetch.nStartPos); l 6.#s3I['  
output.writeLong(fileSplitterFetch.nEndPos); Zp|LCE"  
} f[)_=T+  
output.close(); }vOUf# ^k  
} _q([k_4h  
catch(IOException e){e.printStackTrace ();} ) Qve[O  
catch(Exception e){e.printStackTrace ();} md[FtcY\  
} CL(,Q8yG  
EXz5Rue LV  
I>b-w;cC  
//读取保存的下载信息(文件指针位置) +NRn>1]  
private void read_nPos() W%]sI n  
{ 6p/gvpZ  
try{ x{io*sY-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); x>Ah4a d  
int nCount = input.readInt(); \K 01 F  
nStartPos = new long[nCount]; 4+mawyM  
nEndPos = new long[nCount]; n3{m "h3  
for(int i=0;i<nStartPos.length;i++) fM]McZ9)D  
{ 2aUz.k8o  
nStartPos = input.readLong(); xh> /bU!>  
nEndPos = input.readLong(); "m]"%MU7 8  
} WG 9f>kE  
input.close(); eafy5vN[zX  
} &/ lJ7=Nq  
catch(IOException e){e.printStackTrace ();} G)l[\6Dn  
catch(Exception e){e.printStackTrace ();} qx5X2@-;:  
} JH!qGV1  
_C?<re3*  
)@Yp;=l  
private void processErrorCode(int nErrorCode) f}bUuQrH-!  
{ ]>@; 2%YvY  
System.err.println("Error Code : " + nErrorCode); `$`:PT\Zv4  
} {+[~;ISL  
Yt*M|0bL  
RIX0AE  
//停止文件下载 xJ9_#$ngeM  
public void siteStop() 96F:%|yG  
{ S=lA^#'UdX  
bStop = true; xM%E;  
for(int i=0;i<nStartPos.length;i++) ( 5 d ~0  
fileSplitterFetch.splitterStop(); yy?|q0  
] K7>R0  
?Gl'-tV  
} my")/e  
} ,TU!W|($  
//负责部分文件的抓取 CGg:e:4  
**FileSplitterFetch.java |6B:tw/.  
*/ bl\44VK2'  
package NetFox; $X5~9s1Wl  
-mZo`  
MAR kTxzi  
import java.io.*; l1c&a[M)  
import java.net.*; kETA3(h'  
)iy>sa{  
<Q=ES,M  
public class FileSplitterFetch extends Thread { ^e8R 43w:!  
5h[u2&;G  
P<kTjG  
String sURL; //File URL ZP?k|sEH  
long nStartPos; //File Snippet Start Position c}mJ6Pt  
long nEndPos; //File Snippet End Position #s1M>M)  
int nThreadID; //Thread's ID ;JFE7\-mC  
boolean bDownOver = false; //Downing is over ?9X#{p>q  
boolean bStop = false; //Stop identical c i7;v9  
FileAccessI fileAccessI = null; //File Access interface >4\V/ I  
l{#m"S7J^  
<E@ 7CG.=  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException GMU<$x8o  
{ *cp|lW!ag  
this.sURL = sURL;  -/  
this.nStartPos = nStart; @.*[CC;&  
this.nEndPos = nEnd; ~<, \=;b/  
nThreadID = id; vFb{(gIJ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [CPZj*|b  
} }p t5.'l  
_DC/`_'  
g)$Pvfc  
public void run() OJ UM Y<5  
{ =&"Vf!7YR7  
while(nStartPos < nEndPos && !bStop) D0i84I`Z%  
{ :G^`LyOM  
ENC_#- 1x  
R)cns7oW  
try{ F.A<e #e?  
URL url = new URL(sURL); A&9l|b-"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~J<bwF  
httpConnection.setRequestProperty("User-Agent","NetFox"); /N%f78 Z  
String sProperty = "bytes="+nStartPos+"-"; o9wg<LP  
httpConnection.setRequestProperty("RANGE",sProperty); @+1E|4L1vf  
Utility.log(sProperty); .ET;wK  
JIb<>X,  
Pms3X  
InputStream input = httpConnection.getInputStream(); }C*o;'o5G  
//logResponseHead(httpConnection); K- }k-S  
P+}qaup  
q'(WIv@  
byte[] b = new byte[1024]; !+ uMH!  
int nRead; -(cm  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #]lUJ &M}e  
{ 8.pz?{**T  
nStartPos += fileAccessI.write(b,0,nRead); Wlg(z%  
//if(nThreadID == 1) 1AE/ILGo  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); +{hxEDz  
} y^@% Xrs  
%\~;I73  
)lw7 W9  
Utility.log("Thread " + nThreadID + " is over!"); MruWt*  
bDownOver = true; $+P v fQ  
//nPos = fileAccessI.write (b,0,nRead); a m<R!(  
} Z$zUy|s[  
catch(Exception e){e.printStackTrace ();} \)M 5o  
} Z~?:r  
} ys#M* {?  
eaX`S.!jR  
X3W)c&Pr  
//打印回应的头信息 @1]<LQ\\  
public void logResponseHead(HttpURLConnection con) +ypG<VBx%  
{ \=N tbBL$[  
for(int i=1;;i++) S OK2{xCG  
{ {6%uNT>|  
String header=con.getHeaderFieldKey(i); >t D-kzN  
if(header!=null) ik$wS#1+L  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $,aU"'D  
Utility.log(header+" : "+con.getHeaderField(header)); =R>Sxaq  
else yQi|^X~?$  
break; l*v([@A\  
} =rBFMTllM  
} 7Ck;LF}>0  
}2NH>qvY  
=fsaJ@q ,R  
public void splitterStop() d:pp,N~2o  
{ *<Ddn&_  
bStop = true; zl: u@!'  
} c<D Yk f  
k oHY AF  
@\"*Z&]8z0  
} chd${ j  
}MIH{CMH  
6\TstY3  
/* :.35pp,0  
**FileAccess.java [CUJA  
*//文件访问(定位,写) ?1N0+OW   
package NetFox; y:42H tS  
import java.io.*; '^/E2+  
p9s~WD/K  
z!3Z^d`  
public class FileAccessI implements Serializable{ cw5YjQ8 9  
jSG jv>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :%>8\q>UX  
RandomAccessFile oSavedFile; M`>W'<  
long nPos; KbUX(9+B  
@wFm])}0  
Cfi2N V  
public FileAccessI() throws IOException z9'0&G L  
{ d|o"QYX  
this("",0); jSVO$AW~C  
} ?s?uoZ /2  
L3GJq{t  
'D/AL\1{p(  
public FileAccessI(String sName,long nPos) throws IOException +.N;h-'  
{ 4z*_,@OA  
oSavedFile = new RandomAccessFile(sName,"rw"); @[FFYVru  
this.nPos = nPos; UpIf t=@P  
oSavedFile.seek(nPos); A0]o/IBz  
} Tb)x8-0  
{30<Vc=  
CYn}wkz  
public synchronized int write(byte[] b,int nStart,int nLen) c|.:J]  
{ PaDT)RrEM  
int n = -1; 0iL8i#y*  
try{ <+$S{Z.  
oSavedFile.write(b,nStart,nLen); )F$Stg3e  
n = nLen; 41zeN++  
} .lFSFJ??  
catch(IOException e) IRU2/Ycg  
{ R/wSGP`W  
e.printStackTrace (); s{,e^T  
} /,>.${,;u  
X<QE]RZ  
z<fEJN  
return n; 2"MI8EK  
} 0K2[E^.WN  
:RQ[(zD]  
MMAC,4  
} (s3%1OC[  
BdKtpje  
FO5SXwx  
/* 5`uS<[vA  
**SiteInfoBean.java i3"sAr P"|  
*/ ^0&] .m  
package NetFox; C49 G&  
sXa8(xc  
64vSJx>u  
public class SiteInfoBean { [>:gwl _\  
8$vH&Hd I  
C5M-MZaS  
private String sSiteURL; //Site's URL H<xC%/8  
private String sFilePath; //Saved File's Path %OtW\T=u  
private String sFileName; //Saved File's Name =z/F=1^<  
private int nSplitter; //Count of Splited Downloading File D1n2Z :9  
2|=_kN8;  
kwL) &@  
public SiteInfoBean() :acQK=fe  
{//nSplitter的缺省值为5 d0=nAZZ  
//default value of nSplitter is 5 a82mC r  
this("","","",5); q"Md)?5N  
} 0/6&2  
]]Z,Qu#<-  
8bGq"!w-  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8<kme"% s  
{ #~+#72+x7  
sSiteURL= sURL; >gZz`CH  
sFilePath = sPath; J:u|8>;  
sFileName = sName; uJ`&hX  
this.nSplitter = nSpiltter; S8=4C`>jf  
m?j!0>  
SRTpE,  
} #{M -3  
5a ~tp'  
:#/bA&  
public String getSSiteURL() LasH[:QQQ  
{ )^\='(s  
return sSiteURL; !{Y#<tG]  
} 4BT`|(7  
F^YIZ,=p!  
%5G BMMn  
public void setSSiteURL(String value) m%[t&^b}T  
{ FJLJ;]`7+  
sSiteURL = value; kpH;D=;  
} MuobMD}jqe  
R`Lm"5w  
p*0Ve21i,  
public String getSFilePath() #CPPdU$  
{ E(tBN]W.  
return sFilePath; )sf~l6  
} 'y?|shV{]  
Uot-@|l  
.=yus[,~  
public void setSFilePath(String value) 8zC k9&  
{ Q:gn>/  
sFilePath = value; }$U[5wL,_  
} 'j_H{kQy  
>bN~p  
<L~xR5  
public String getSFileName() sAoM=n}!  
{ zy[=OX+  
return sFileName; 9i}D6te  
} .$0Ob<.  
m0Syxb  
u-{l,p_H  
public void setSFileName(String value) ql~{`qoD~  
{ Z0eBx  
sFileName = value; ;g:bn5G  
} :BX{ *P  
)$B+ 3f  
n\-_i2yy  
public int getNSplitter() ^\&g^T%  
{ ;a&:r7]=  
return nSplitter; oKi1=d+T  
} el?V2v[  
r^t{Ii ~  
1N!g`=}  
public void setNSplitter(int nCount) cN7z(I0[  
{ Z9&D'n)  
nSplitter = nCount; 8-a6Q|   
} uX +<`3O  
} 1Wk EPj,  
\83A|+k  
^|GtO.  
/* oqba:y;AR  
**Utility.java ms7 7{A3  
*/ %^=!s  
package NetFox; 5TneuGD  
1[BvHOI2  
g>xUS_d>  
public class Utility { '$XHRS/q]  
J,G9m4Z7  
{7Avba  
public Utility() P! Ed  
{ /iy*3P,`  
h+3Z.WKhwP  
`4.sy +2  
} Ig3(|{R  
g]<Z]R`  
//线程睡眠 ` G=L07  
public static void sleep(int nSecond) )H9*NB8%  
{ (oitCIV  
try{ bmVgTm&  
Thread.sleep(nSecond); W)!{U(X  
} 5@D7/$bLp  
catch(Exception e) $xtE+EV.p  
{ 1m`tqlFU9  
e.printStackTrace (); 7~ese+\smG  
} DRW.NL o  
} i!W8Q$V  
S@xsAib0J  
//日志 pLQSG}N  
public static void log(String sMsg) )L<?g !j~  
{ Z4AAg  
System.err.println(sMsg); G 0QXf  
} ]jVSsSv  
zrU$SWU  
tOM3Gs~o6z  
public static void log(int sMsg) 4@]xn  
{ #* gU[9U~  
System.err.println(sMsg); _'hCUXeY'  
} ab aQJ|  
} DV[ Jbl:)  
@`;Y/',  
2Z`$  
/* Ac!&j=ZE  
**TestMethod.java + %#MrNM'  
*/ l?JO8^Nn  
package NetFox; 4 ?@uF[  
aT1CpY=T|.  
ah/6;,T  
public class TestMethod { Hx2j=Q_dw  
vYSetAd v  
(: TGev  
public TestMethod() UiK+c30FU  
{ ///xx/weblogic60b2_win.exe *lerPY3 q  
try{ y/}VtD  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); k~jKJb-_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8q~FUJhU  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {{]=zt|69  
fileFetch.start(); /y](mu"!  
} QK?2E   
catch(Exception e){e.printStackTrace ();} ?St=7a(D  
5{ 4"JO3  
$uUb$8 Bu  
} moVa'1ul  
g;-+7ViIr  
BH#C<0="  
public static void main(String[] args) StyB"1y  
{  w{ r(F`  
new TestMethod(); l<aqiZSY  
} ,dZ H$  
} 8XYD L] I'  
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