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http断点续传简单实现(java)

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/* Q@@v1G\  
**SiteFileFetch.java QK`i%TXJ  
*/ P u0uKE  
package NetFox; a4i:|   
import java.io.*; ;z~n.0'  
import java.net.*; C0*@0~8$9  
U`|0 jJ  
*i{Y9f8  
public class SiteFileFetch extends Thread { ^!8P<y  
efP&xk  
'3IC*o"  
SiteInfoBean siteInfoBean = null; //文件信息Bean -62'}%?A<C  
long[] nStartPos; //开始位置 E\nv~Y?SG  
long[] nEndPos; //结束位置 Va VN  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 in`aGFQO  
long nFileLength; //文件长度 &sXRN &Fp  
boolean bFirst = true; //是否第一次取文件 wd(Hv  
boolean bStop = false; //停止标志 VdSv  
File tmpFile; //文件下载的临时信息 R9rj/Co  
DataOutputStream output; //输出到文件的输出流 jjM\.KL]  
kql0J|P?  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) YXurYwV  
public SiteFileFetch(SiteInfoBean bean) throws IOException Em 6Qe  
{ Nc Pgq?3p  
siteInfoBean = bean; 8X|r4otn4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); vIl+#9L0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); so$(_W3E,  
if(tmpFile.exists ()) S& #U!#@  
{ 0 [?ny`Y  
bFirst = false; &UCsBqIY  
read_nPos(); @+F4YJmB?l  
} Cv ejb+  
else ?Iyo9&1&  
{ W!!S!JF  
nStartPos = new long[bean.getNSplitter()]; obrl#(\P  
nEndPos = new long[bean.getNSplitter()]; vDl- "!G1  
}  Uo12gIX  
65h @}9,U  
,#d? _?/:O  
~=<}\a~  
} U7uKRv9  
jcNT<}k C  
ae"]\a\&1o  
public void run() $N :Vo(*  
{ "<_0A f]  
//获得文件长度 lv vs%@b>  
//分割文件 "8^5>EJWv  
//实例FileSplitterFetch 53-v|'9'  
//启动FileSplitterFetch线程 8t@p @Td|  
//等待子线程返回 "s!7dKXI"  
try{ x8\A<(G_M=  
if(bFirst) Hqnxq  
{ #ET/ =  
nFileLength = getFileSize(); :1t~[-h^  
if(nFileLength == -1) wC `+  
{ W^3uEm&l!)  
System.err.println("File Length is not known!"); 322jR4QGr  
} ]EwVpvTw  
else if(nFileLength == -2) r]3'74j:  
{ J psPNa  
System.err.println("File is not access!"); <E\$3Ym9  
} K=!Bh*  
else fwK}/0%  
{ (b'B%rFO  
for(int i=0;i<nStartPos.length;i++) V $z} K  
{ =@k%&* Y?  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); AU-n&uX  
} &>e-(4Xu  
for(int i=0;i<nEndPos.length-1;i++) Og=*R6i  
{ ^c:Fy+fb  
nEndPos = nStartPos[i+1]; "#(T  
} rx (2yf  
nEndPos[nEndPos.length-1] = nFileLength;  /'31w9  
} 6s0_#wZC  
} \(t@1]&jw  
}%Bl>M  
\:'%9 x  
//启动子线程 u%~igt@x  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; r5!/[_l  
for(int i=0;i<nStartPos.length;i++) ?c0xRO%y  
{ rvr-XGK36\  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), p~*UpU8u  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), L%>n>w  
nStartPos,nEndPos,i); pp7$J2s+j  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); tv!_e$CR  
fileSplitterFetch.start(); H\XP\4#u  
} ChCrL [2  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f4L`.~b'hb  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6xD#?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", h6} lpd  
nEndPos = " + nFileLength); pZtu&R%GU  
// fileSplitterFetch[nPos.length-1].start(); ;j4?>3  
r\AyN= y  
ID#I`}h.k  
//等待子线程结束 765p/**  
//int count = 0; -?(E_^ng  
//是否结束while循环 1KjU ] r2  
boolean breakWhile = false; )Tk1 QHU  
6;|n]m\Vd  
9 7ql5  
while(!bStop) Z!U)I-x&  
{ F'hHK.tT  
write_nPos(); 8T(e.I  
Utility.sleep(500); @xB*KyUW  
breakWhile = true; r2k2%nI-J  
e^ v.)  
jg?x&'u\)  
for(int i=0;i<nStartPos.length;i++) ar:+;.n  
{ byv[yGa`  
if(!fileSplitterFetch.bDownOver) !"eIV@7  
{ Y5F]:gs@  
breakWhile = false; ( H6c{'&  
break; U#3J0+!  
} sP ls zC[  
} +|tC'gCnV  
if(breakWhile) =2@B&  
break; Yot?=T};3{  
D$T%\ P  
 Br` IW  
//count++; WD1G&5XP  
//if(count>4) ,Jd ',>3  
// siteStop(); /{|fyKo\?  
} R9B&dvG  
+"1NC\<*  
`3:.??7N  
System.err.println("文件下载结束!"); sqW* pi  
} %Qj;,#z  
catch(Exception e){e.printStackTrace ();} %Q.&ZhB  
} =9j8cC5y  
F+@5C:<?  
s>^dxF!+  
//获得文件长度 e [8LmuIZ  
public long getFileSize() v'e[GB 0  
{ ;X?mmv'  
int nFileLength = -1; X,LD   
try{ `\+@Fwfx  
URL url = new URL(siteInfoBean.getSSiteURL()); 7e<c$t#H  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p ZZc:\fJ  
httpConnection.setRequestProperty("User-Agent","NetFox"); Kw#i),M  
7^g&)P  
Aj0Tfdxy  
int responseCode=httpConnection.getResponseCode(); 2 aL)  
if(responseCode>=400) VZ\B<i  
{ A,`8#-AX  
processErrorCode(responseCode); Qci4J  
return -2; //-2 represent access is error i F+vl]  
} =KR NvW  
f aLtdQi  
&9Xhl''  
String sHeader; Mb]rY>B4  
0pbtH8~  
;g~TWy^o  
for(int i=1;;i++) #y%!\1M/:A  
{ ~ {Mn{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); n(el]_d  
//Utility.log(in.readLine()); pZeE61c/  
sHeader=httpConnection.getHeaderFieldKey(i); Q_t`.jus  
if(sHeader!=null) Ry|!pV  
{ $H-!j%hV  
if(sHeader.equals("Content-Length")) (`:O~>[N  
{ AhNq/?Q Q~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); xe*aC  
break; 6qaulwV4t  
} &SrO)  
} 65Cg]Dt71  
else W]nSR RWco  
break; 1n@8Kv  
} 2"B_At  
} 0q'w8]m  
catch(IOException e){e.printStackTrace ();} )4&cph';  
catch(Exception e){e.printStackTrace ();} {\(L%\sV@  
^g`&7tX  
TsGE cxIg  
Utility.log(nFileLength); o9H^?Rut  
3#TV5+x*"`  
w.0qp)}  
return nFileLength; 1u6^z  
} HTyLJe  
B~_d^`  
~SnSEhE  
//保存下载信息(文件指针位置) 7bV{Q355P  
private void write_nPos() /;utcc  
{ a(0*um(  
try{ smry2*g  
output = new DataOutputStream(new FileOutputStream(tmpFile)); TEaJG9RU>v  
output.writeInt(nStartPos.length); Ck!VV2U#  
for(int i=0;i<nStartPos.length;i++) +*hm-lv?  
{ :Cp'm'omb  
// output.writeLong(nPos); /=gOa\k|p  
output.writeLong(fileSplitterFetch.nStartPos); 2^l[(N  
output.writeLong(fileSplitterFetch.nEndPos); =hMY2D  
} R<=zCE`:  
output.close(); ~>+]%FPv  
} LH@j8YB5u  
catch(IOException e){e.printStackTrace ();} Yx>"bv  
catch(Exception e){e.printStackTrace ();} A$a1(8H  
} n2fbp\I  
<Ce2r"U1e  
(owrdPT!  
//读取保存的下载信息(文件指针位置) uECsh2Uin  
private void read_nPos() Gqy,u3lE  
{ F  3'9u#  
try{ 1hziXC0WY  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); th&[Nt7  
int nCount = input.readInt(); P [k$vD  
nStartPos = new long[nCount]; a! u rew#  
nEndPos = new long[nCount]; 1rDqa(7  
for(int i=0;i<nStartPos.length;i++) y})70w@ +_  
{ w18y}mS"H  
nStartPos = input.readLong(); @!8ZPiW<  
nEndPos = input.readLong(); ryFxn|4  
} 6O}`i>/6M  
input.close(); *Otg*, \  
} Z%n(O(^L  
catch(IOException e){e.printStackTrace ();} ]| +<P-  
catch(Exception e){e.printStackTrace ();} Co3:*nbRv  
} ]hbyELs  
^*fxR]Y  
-G|G_$9  
private void processErrorCode(int nErrorCode) /0eYMG+K=  
{ rQaxr!  
System.err.println("Error Code : " + nErrorCode); W[}s o6  
}  &CG*)bE  
vVgg0Y2  
R%c SJ8O#  
//停止文件下载 XB_B4X1R  
public void siteStop() Jzp#bgq}|  
{ Nq@+'<@p$  
bStop = true; ~O1&@xX  
for(int i=0;i<nStartPos.length;i++) L^{|uP15N  
fileSplitterFetch.splitterStop(); PtTHPAKj  
5=1^T@~#&  
D2,z)O%VK  
} wWp(yvz  
} =lVK IW  
//负责部分文件的抓取 +|ycvHd  
**FileSplitterFetch.java zrU{@z$l  
*/ Usta0Ag  
package NetFox; uZ=NSbYsA  
H/"lAXfb  
v%RP0%%{s  
import java.io.*; 3dDX8M?  
import java.net.*; kn/Ao}J74z  
YXI'gn2b#  
l3IWoa&sh  
public class FileSplitterFetch extends Thread { >(snII  
bl'z<S, '  
<~)kwq'  
String sURL; //File URL jH6&q~#  
long nStartPos; //File Snippet Start Position J;prC  
long nEndPos; //File Snippet End Position $/7pYl\n  
int nThreadID; //Thread's ID +Lnsr\BA  
boolean bDownOver = false; //Downing is over ku..aG`  
boolean bStop = false; //Stop identical hnznp1[#@  
FileAccessI fileAccessI = null; //File Access interface wGZR31  
\{EpduwZ  
&wB\ ~Ie-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException :(H>2xS,s  
{ Zx d~c]n  
this.sURL = sURL; Z?O *'#yn  
this.nStartPos = nStart; K_ ci_g":  
this.nEndPos = nEnd; C*G=cs\i  
nThreadID = id; D3x/OyG(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 q@jq0D)g  
} k`x=D5s\  
Y OJ6 w  
}`NU@O#  
public void run() [S@}T zE  
{ 0V!l,pg  
while(nStartPos < nEndPos && !bStop) 1DA1N<'  
{ {Ions~cO)  
T_lsGu/  
ymNnkFv  
try{ NVl [kw  
URL url = new URL(sURL); zR32PG>9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yu;SH[{Wi  
httpConnection.setRequestProperty("User-Agent","NetFox"); .&x}NYX4  
String sProperty = "bytes="+nStartPos+"-"; ]K*8O <  
httpConnection.setRequestProperty("RANGE",sProperty); sQ 8s7l0D  
Utility.log(sProperty); 7 K{Nb  
84{Q\c  
A%2:E^k(s  
InputStream input = httpConnection.getInputStream(); Y1arX^Zb  
//logResponseHead(httpConnection); ?}B:  
8L1ohj  
%xQ.7~  
byte[] b = new byte[1024]; .WQ+AE8Q  
int nRead; oQL59XOT4  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 8+Td-\IMk  
{ {vE(l'  
nStartPos += fileAccessI.write(b,0,nRead); aceZ3U>W  
//if(nThreadID == 1) C8L'si  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); . ]8E7  
} n\ Hs@.  
>~\89E 02  
MJ\eh>v&  
Utility.log("Thread " + nThreadID + " is over!"); %r iK+  
bDownOver = true; k'PQ} ,Vb  
//nPos = fileAccessI.write (b,0,nRead); 3.)b4T  
} o#[ KS:Y  
catch(Exception e){e.printStackTrace ();} Q_vW3xz  
} U #~;)fZ  
} :>81BuMvg  
b,IocD6v;P  
&ciN@nJ|$z  
//打印回应的头信息 S{K0.<,E  
public void logResponseHead(HttpURLConnection con) 8/"fWm/  
{ q-Qxbg[>e  
for(int i=1;;i++) P6Mhbmt9*  
{ wP/A^Rs  
String header=con.getHeaderFieldKey(i); Eaqca{%/^  
if(header!=null) ?J,AB #+  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); j.:h5Y^N  
Utility.log(header+" : "+con.getHeaderField(header)); x3zj ?-  
else 'r\ V. 4  
break; S:61vD  
} |0z;K:5s  
} "Y=+Ls(3o(  
U'*t~x <  
-ti{6:H8  
public void splitterStop() "3F;cCDv]  
{ pDh se2  
bStop = true; #pHs@uvO  
} _U{&@}3  
&J!aw  
6q>+!kXh  
} [/_+>M  
p*l$Wj  
F6hmku>\1  
/* A!63p$VT;  
**FileAccess.java |([R'Orm  
*//文件访问(定位,写) /1`cRyS  
package NetFox; }!TL2er_  
import java.io.*; Bg8#qv  
C;~*pMAYe  
%/.a]j!  
public class FileAccessI implements Serializable{ ,pBh`av  
T$= 4O9G  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Q7bq  
RandomAccessFile oSavedFile; pA4*bO+  
long nPos; ]h9!ei [  
[ REf>_R  
C}5M;|%3)  
public FileAccessI() throws IOException u? fTL2~  
{ #?B%Ja% ;W  
this("",0); 1=2^90  
} u z\0cX_  
q/1Or;iK  
z}Jr^>  
public FileAccessI(String sName,long nPos) throws IOException s4H2/EC  
{ 4ujvD^  
oSavedFile = new RandomAccessFile(sName,"rw"); t_ur&.^SB  
this.nPos = nPos; A`6ra}U<  
oSavedFile.seek(nPos); )$Z(|M4  
} P;]F=m+ *V  
[hRU&z;W  
:!zC"d9@  
public synchronized int write(byte[] b,int nStart,int nLen) V,ZY*f0  
{ m?[5J)eR  
int n = -1; H0"=Vs,n  
try{ n +1y  
oSavedFile.write(b,nStart,nLen); Qju`e Eo  
n = nLen; V^il$'  
} -p-0;Hy  
catch(IOException e) 3_5XHOdE  
{ W0cgI9=9  
e.printStackTrace (); %}>dqUyQ  
} a1N!mQ^  
Wd(86idnc  
}vt%R.u  
return n; v0l_w  
} $WW)bP d4^  
lnbmoHv  
'YSuQP>  
} ;,O fJ'q^  
;\%sEcpT  
RD<75]**{  
/* l|/:Ot  
**SiteInfoBean.java Z"I/ NGiU  
*/ MQcr^Y_  
package NetFox; |Wj;QO$C  
\0FT!} L  
~9$X3.+  
public class SiteInfoBean { y:}sD_m0W  
{fSf q&o  
1q.(69M  
private String sSiteURL; //Site's URL p D=w >"  
private String sFilePath; //Saved File's Path tu%[p 4   
private String sFileName; //Saved File's Name ]qw0V   
private int nSplitter; //Count of Splited Downloading File bZipm(e  
")lw9t`  
84&XW  
public SiteInfoBean() oYM,8 K  
{//nSplitter的缺省值为5 uL?vG6% ^1  
//default value of nSplitter is 5 7]2 2"mc  
this("","","",5); d @rs3Q1z  
} t"s5\;IJ  
UU@fkk  
19d6]pJ5  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) q9}m!*8e  
{ ?$%%Mp(  
sSiteURL= sURL; q'(z #h,cv  
sFilePath = sPath; Q1tpCT  
sFileName = sName; =7ydk"xM*  
this.nSplitter = nSpiltter; 0-2"FdeQU  
hRTMFgO  
PCfo  
} @Z\~  
;6DnId2Zh  
&$ p[  
public String getSSiteURL() LP`CS849z2  
{ PJ 9%/Nrh  
return sSiteURL; E20 :uZ7\  
}  U w Eiz  
%%g-GyP 1  
{K7YTLWY  
public void setSSiteURL(String value) 0rzVy/Z(  
{ _ 6:ww/  
sSiteURL = value; $3\yf?m}q  
} F=&;Y@t  
3q &k  
QB 77:E  
public String getSFilePath() t=dO  
{ `mB.pz[  
return sFilePath; 4#Eul  
} l C\E  
wq72% e  
e.X@] PQJQ  
public void setSFilePath(String value) n,KA&)/s  
{ 3ps,uozj  
sFilePath = value; C{Blqf3V0  
} D@vMAW  
\f"?Tv-C'  
N8+P  
public String getSFileName() ,k*F`.[  
{ &=-PRza%j  
return sFileName; o'qm82* =  
} vR]mSX3)?  
l \}25 e  
/PC` 0/b  
public void setSFileName(String value) #%cR%Z  
{ jzrt7p*k}  
sFileName = value; 6An{3 "  
}  `$-lL"  
r'd/qnd  
}[,3yfiX  
public int getNSplitter() ~n]NyVFP  
{ ?'2 v.5TQt  
return nSplitter; %CT!$Y'n  
} ahp1!=Z-=  
u33zceE8  
UB&2f>  
public void setNSplitter(int nCount) J~dTVBx  
{ o>!JrH  
nSplitter = nCount; N5\{yV21",  
} #Wx=v$"  
} nW&$~d  
rv?!y8\  
2nx9#B*/T  
/* WF)s*$'uz;  
**Utility.java r~[B _f!  
*/ K\X: G-C9  
package NetFox; Mdky^;qq3;  
gfVDqDF  
E$T(Qu<-  
public class Utility { A\C'dZ <N  
'bm:u  
IHVMHOq}'  
public Utility() yfq>,  
{ yjeL9:jH[  
q u:To7  
Ws>i)6[  
} 6!RikEAh  
-aN":?8(G  
//线程睡眠 ,cS0  
public static void sleep(int nSecond) 3k{c$x}  
{ ._ih$=   
try{ ^^ j/  
Thread.sleep(nSecond); _3U|2(E  
} l4Y1(  
catch(Exception e) "7?t)FOo  
{ xSOoIsL[  
e.printStackTrace (); t 2G1[j!  
} u#VweXyU  
} 8GW ut=D  
SW=aHM  
//日志 *2#FRA#q  
public static void log(String sMsg) `uhL61cMp  
{ .$^wy3:F"  
System.err.println(sMsg); CLktNR(45  
} ?w8p LE~E  
.m!s". ?[  
sZEgsrJh  
public static void log(int sMsg) (NM6micc  
{ H8<m9zDvl  
System.err.println(sMsg); !?n50  
} 7BK46x  
} 776 nWw)  
!*8#jy  
PAr|1i)mB  
/* .f+9 A>  
**TestMethod.java RSFJu\0}N  
*/ jDJ.  
package NetFox; Hz5;Ruw'  
sM0c#YK?  
Kv1vx*>  
public class TestMethod { <]c#)xg  
o6/Rx#A  
X -v~o/r7  
public TestMethod() UCn.t  
{ ///xx/weblogic60b2_win.exe 5{HtJ?sKc5  
try{ 6s&qZ+v-  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); { $X X  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &EGY+p|2Y  
SiteFileFetch fileFetch = new SiteFileFetch(bean); n)Hk8)^8  
fileFetch.start(); RAdvIIQp:  
} T[m ~6  
catch(Exception e){e.printStackTrace ();} Q{8qm<0g  
SUo^c1)G  
rEg+i@~  
} <gR`)YF7  
8 `o{b"l+  
C*$|#.l  
public static void main(String[] args) s7vPI   
{ ]}/mFY?7  
new TestMethod(); |o|gP8  
} yIlV[_  
} F1E. \l  
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