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http断点续传简单实现(java)

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/* d/,E2i{I7  
**SiteFileFetch.java +cB&Mi5  
*/ >cR)?P/o  
package NetFox; p@Q5b}xCG_  
import java.io.*; @gfDp<  
import java.net.*; RW7(r/C  
7C,T&g 1:  
IB5BO7J  
public class SiteFileFetch extends Thread { ;N=G=X|}  
Ug"rJMZG  
SZ!=`a]  
SiteInfoBean siteInfoBean = null; //文件信息Bean [`_io>*g  
long[] nStartPos; //开始位置 :+&AY2`  
long[] nEndPos; //结束位置 @R2at  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 4Yjx{5QSAG  
long nFileLength; //文件长度 y2yKm1<Ru<  
boolean bFirst = true; //是否第一次取文件 "^CXY3v  
boolean bStop = false; //停止标志 bE\,}DTy  
File tmpFile; //文件下载的临时信息 +: Ge_-  
DataOutputStream output; //输出到文件的输出流 lE#m]D  
T1Ta?b  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) *~VxC{  
public SiteFileFetch(SiteInfoBean bean) throws IOException 40P) 4w  
{ 4FMF|U  
siteInfoBean = bean; 6`H.%zM  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); xi'>mIT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ^4$ 'KIq  
if(tmpFile.exists ()) cPF<D$B  
{ ;[0&G6g  
bFirst = false; C2F0tr|  
read_nPos(); ~oD8Rnf  
} 2y GOzc  
else i%{X9!*%TX  
{ .p6+l!"  
nStartPos = new long[bean.getNSplitter()]; 9s$U%F6}  
nEndPos = new long[bean.getNSplitter()]; & eZfQ27$  
} Y:QD   
P\R27Jd  
h3G.EM:eG  
g:)DNy  
} w7kJg'X/6  
U8QX46Br  
CnF |LTi  
public void run() iU2KEqCm  
{ LLAa1Wq  
//获得文件长度 uQ Co6"e  
//分割文件 WMuD}s  
//实例FileSplitterFetch Mtm OUI&'  
//启动FileSplitterFetch线程 ^CT&0  
//等待子线程返回 yX/";Oe  
try{ NY B[Zyp  
if(bFirst) )LHj+B  
{ '3(l-nPiG^  
nFileLength = getFileSize(); \ZXLX'-  
if(nFileLength == -1) 7*H:Ob)9k  
{ e;95a  
System.err.println("File Length is not known!"); SAv<&  
} `k{& /]  
else if(nFileLength == -2) \c`oy=qY0  
{ Es5p}uh.[Y  
System.err.println("File is not access!"); ra7uU*  
} qv{o |g QB  
else j6}R7 $JR  
{ ZU&"73   
for(int i=0;i<nStartPos.length;i++) fZWGn6$   
{ rXi uwz\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); TCVl8)j  
} E@)\Lc~  
for(int i=0;i<nEndPos.length-1;i++) C*70;:b  
{ Kp iF0K  
nEndPos = nStartPos[i+1]; 9h,u6e  
} 5_o$<\I\  
nEndPos[nEndPos.length-1] = nFileLength; ./-JbW  
} }ynT2a#LU'  
} E8}+k o  
!b|'Vp^U  
.w? .ib(  
//启动子线程 s4= "kT]  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0Fr1Ku!  
for(int i=0;i<nStartPos.length;i++) b3qc_  
{ VV_l$E$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B0UJq./`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ZXb0Y2AVx  
nStartPos,nEndPos,i); wdE?SDs  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %'Xk)-+y  
fileSplitterFetch.start(); &~DTZg Y  
} Z'v-F^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T6 #"8qz<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 'W. V r4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v6a]1B   
nEndPos = " + nFileLength); Jc*XXu)  
// fileSplitterFetch[nPos.length-1].start(); kMxazx1  
tJI,r_  
w5C*L)l  
//等待子线程结束 BNGe exs@  
//int count = 0; WgR4Ix^L#  
//是否结束while循环 *<V^2z$y_  
boolean breakWhile = false;  3yS  
TW&DFKK`  
JN3cg  
while(!bStop) ``Q 2P%  
{ 7YIK9edP  
write_nPos(); D@YP7  
Utility.sleep(500); p#8W#t$  
breakWhile = true; {==pZpyyh  
=(r* 5vd  
$6f\uuTU2"  
for(int i=0;i<nStartPos.length;i++) B)SLG]72f  
{ vFmJ;J  
if(!fileSplitterFetch.bDownOver) vxlOh.a|/L  
{ wzcai 0y*  
breakWhile = false; USML~]G z  
break; v[k5.\No  
} \&xl{64  
} J QKdW  
if(breakWhile) V2&^!#=s  
break; 25{ uz  
**_&i!dtL  
")#<y@Rv  
//count++; ak:v3cQR  
//if(count>4) qztV,R T  
// siteStop(); > 6CV4 L  
} !3&kQpF  
8|1^|B(l  
Eh8Pwt7C@  
System.err.println("文件下载结束!"); 2h~-  
} f?fKhu2  
catch(Exception e){e.printStackTrace ();} N"5fmY<  
} +54aO  
VkmRh,T  
D@Da0  
//获得文件长度 8pZ< 9t'  
public long getFileSize() t@zdm y  
{ KlxN~/gyik  
int nFileLength = -1; "`tXA  
try{ eBW=^B"y+  
URL url = new URL(siteInfoBean.getSSiteURL()); Jcf"#u-Q/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P8yIegPY  
httpConnection.setRequestProperty("User-Agent","NetFox"); nn~YK  
C"<s/h  
TvhJVVQ+?  
int responseCode=httpConnection.getResponseCode(); my\&hCE  
if(responseCode>=400) Iq5pAHm>M6  
{ b}z`BRCc  
processErrorCode(responseCode); .#6MQJ]OH  
return -2; //-2 represent access is error RNJ FSD.  
} NC23Z0y  
'%iPVHK7  
PBqy F  
String sHeader; +",S2Qmo  
$K}. +`vVO  
('k<XOi  
for(int i=1;;i++) @M;(K<%h  
{ ?s%v0cF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $< %B#axL  
//Utility.log(in.readLine()); |WqOk~)[Z3  
sHeader=httpConnection.getHeaderFieldKey(i); 7v~j=Z>  
if(sHeader!=null) 'VnwG  
{ c=p=-j=.J  
if(sHeader.equals("Content-Length")) T.&7sbE_  
{ `x8B n"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8QgA@y"  
break; u</8w&!  
} I+?hG6NM  
} t1]6(@mj5  
else qk{'!Ii  
break; <lwuTow  
} %IZ)3x3l  
} JNU/`JN9f  
catch(IOException e){e.printStackTrace ();} }<m{~32M  
catch(Exception e){e.printStackTrace ();} ; 2`sN   
}7/e8 O2  
E)p9eU[#  
Utility.log(nFileLength); sa-9$},z4  
6F0(aGs  
v"6 \=@  
return nFileLength; 5 9 2;W-y  
} V^fV7hw<  
:- +4:S  
NlPS#  
//保存下载信息(文件指针位置) 2Oc$+St~8  
private void write_nPos() ? 5|/ C  
{ 2ypIq  
try{ ISqfU]>[  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $ @1u+w  
output.writeInt(nStartPos.length); ZW4aY}~)$  
for(int i=0;i<nStartPos.length;i++) mf$j03tu  
{ YcM;S  
// output.writeLong(nPos); t 0O4GcAN  
output.writeLong(fileSplitterFetch.nStartPos); f?UzD#50D  
output.writeLong(fileSplitterFetch.nEndPos); L10IF  
} %_)zWlN  
output.close(); [s6C ZcL  
} 7!4V >O8@  
catch(IOException e){e.printStackTrace ();} >.%4~\U  
catch(Exception e){e.printStackTrace ();} 1 =GI&f2I  
} kA?_%fi1  
aq>?vti1D  
M@7Xp)S"  
//读取保存的下载信息(文件指针位置) Ej(2w Q  
private void read_nPos() h[Tk; h  
{ ] f 7#N  
try{ "~+.Af  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )C]x?R([m  
int nCount = input.readInt(); V0i9DK|!  
nStartPos = new long[nCount]; G?)vWM`j  
nEndPos = new long[nCount]; .Ao0;:;(2-  
for(int i=0;i<nStartPos.length;i++) MK$Jj "  
{ q?  z>  
nStartPos = input.readLong(); |ng%PQq)  
nEndPos = input.readLong(); s@@1 *VQ  
} Ob@Hng% v  
input.close(); BWK IbG  
} f6ZZ}lwaV  
catch(IOException e){e.printStackTrace ();} I 48VNX  
catch(Exception e){e.printStackTrace ();} ,@CfVQz  
} LJuW${Y  
8C&x MA^  
Gp2!xKgm  
private void processErrorCode(int nErrorCode) lgD]{\O$ip  
{ &d^=s iL  
System.err.println("Error Code : " + nErrorCode); %$X\"  
} zQfkMa.  
qd2xb8r  
i57( $1.  
//停止文件下载 y?:dE.5p|  
public void siteStop() YMzBAf  
{ /^<en(0=P  
bStop = true; !D:k!  
for(int i=0;i<nStartPos.length;i++) ,)#.a%EKA  
fileSplitterFetch.splitterStop(); zY APf &5  
/6tcSg)  
EZj1jpL  
} vDDljQXw4  
} C3"&sdLb$  
//负责部分文件的抓取 $G";2(-k  
**FileSplitterFetch.java gA:TL{X0  
*/ 0D3OE.$0  
package NetFox; tbur$ 00  
[X"k> Sq  
VTw/_Hf2p  
import java.io.*; ~ =.CTm]vf  
import java.net.*; $$gtZ{ukQ  
0s%6n5>  
SGf9U^ds  
public class FileSplitterFetch extends Thread { P;U@y" s  
>4)g4~'n!  
YKx 1NC  
String sURL; //File URL Jt=>-Spj  
long nStartPos; //File Snippet Start Position g9V.13k  
long nEndPos; //File Snippet End Position 5' \)`  
int nThreadID; //Thread's ID -u6#-}S  
boolean bDownOver = false; //Downing is over lX;mhJj!  
boolean bStop = false; //Stop identical MUwVG>b8J~  
FileAccessI fileAccessI = null; //File Access interface /$`;r2LG  
h}6_ybmZ  
tgN92Q.i6T  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #5{sglC"|F  
{ j%xBo:  
this.sURL = sURL; Bw-s6MS  
this.nStartPos = nStart; Vyt E  
this.nEndPos = nEnd; *{[d%B<lp  
nThreadID = id; [x_s/"Md;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 rm|7 [mK  
} %V_eJC""?  
$9H[3OZPVv  
jT^!J+?6K+  
public void run() Bl4 dhBZoO  
{ fN[n>%)VO<  
while(nStartPos < nEndPos && !bStop) pGkef0p@  
{ 9ECS,r*B  
0vckoE  
_S5gcPcF"  
try{ !; WbOnLP  
URL url = new URL(sURL); -1mvhR~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); d}% (jJ(I  
httpConnection.setRequestProperty("User-Agent","NetFox"); `o-*Tr  
String sProperty = "bytes="+nStartPos+"-"; lU$X4JBzS  
httpConnection.setRequestProperty("RANGE",sProperty); z93nYY$`Y  
Utility.log(sProperty); ;&mxqY8`'  
6ZgNHARS  
ZNy9_a:dX  
InputStream input = httpConnection.getInputStream(); I9/KM4&  
//logResponseHead(httpConnection); %UG/ak%z  
^pw7o6}  
=uc^433.  
byte[] b = new byte[1024]; $rB!Ex{@ac  
int nRead; ?`i|" y #  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b%<jUY  
{ P#bm uCOS  
nStartPos += fileAccessI.write(b,0,nRead); *`.LA@bHU  
//if(nThreadID == 1) yA}nPXrd  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BhkAQEsWTQ  
} Iaa|qJ4  
Wa, 7P2r  
p">WK<N  
Utility.log("Thread " + nThreadID + " is over!"); {X]9^=O"  
bDownOver = true; .EzSSU7n)  
//nPos = fileAccessI.write (b,0,nRead); 3_U\VGm  
} enPYj.*/0  
catch(Exception e){e.printStackTrace ();} Hdna{@~  
} sH@  &*  
} U,HS;wo;t  
6vWii)O.D  
s((b"{fFb  
//打印回应的头信息 ">,K1:(D  
public void logResponseHead(HttpURLConnection con) Ou!)1UFI  
{ eoL0^cZj  
for(int i=1;;i++) B[7A  
{ FvA|1c  
String header=con.getHeaderFieldKey(i); @7X\tV.Z  
if(header!=null) QX+Y(P`vMK  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'A1E^rl]=  
Utility.log(header+" : "+con.getHeaderField(header)); *vD/(&pQ1:  
else E6Q91Wz9f  
break; QRiF!D)Nk  
} 0STk)> 3$-  
} SZE`J:w  
4K'|DO|dH  
ZmP1C`>  
public void splitterStop() o{g@Nk'f  
{ ~D_ rZ&  
bStop = true; :SdIU36  
} C#T)@UxBZ  
.W-=x,`hY4  
. Nk6  
} *V<)p%l.  
3l+|&q[v  
0@w&J9yG  
/* - BjEL;  
**FileAccess.java /rOnm=P+Q  
*//文件访问(定位,写) Y` q!V=  
package NetFox; w&9F>`VET  
import java.io.*; \CDAFu#  
7s!AH yZ  
%'kX"}N/  
public class FileAccessI implements Serializable{ JkJhfFV  
> `0| X  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 yq!CWXZ2  
RandomAccessFile oSavedFile; ~6MMErSj  
long nPos; (w}r7`n  
qjzZ}  
69-$Wn43<  
public FileAccessI() throws IOException y^, "gD  
{ '&/(oJ ;O~  
this("",0); % hNn%Oy:E  
} @_(nd57oSs  
G1A$PR  
-z&9 DWH  
public FileAccessI(String sName,long nPos) throws IOException VBhE{4J  
{ ?3n=m%W,J*  
oSavedFile = new RandomAccessFile(sName,"rw"); qPp]K?.  
this.nPos = nPos; 2,+@# q  
oSavedFile.seek(nPos); rdFs?hO  
} pDP33`OFh  
<%he  o  
rT o%=0P  
public synchronized int write(byte[] b,int nStart,int nLen) 1X Q87~  
{ )!BB/'DRQ  
int n = -1; KqFmFcf|  
try{ s!bHS_\e|  
oSavedFile.write(b,nStart,nLen); +V6j`  
n = nLen; rknzo]N,  
} MG;4M>H  
catch(IOException e) IM$ 'J  
{ LxIuxt=X|p  
e.printStackTrace (); `Nkx7Z~w:  
} 7eTA`@v5A  
;.L!%$0i#  
`Uu^I   
return n; G &m>Ov$#&  
} [;)~nPjI  
:U7;M}0  
 n})  
} $&bU2]  
DrW/KU,{+(  
LPsh?Ca?N  
/* %L.lkRs  
**SiteInfoBean.java _P>1`IR  
*/ l)|z2 H  
package NetFox; !d/`[9jY  
 <Wp`[S]r  
9Y;}JVS  
public class SiteInfoBean { <?{ SU   
\XZU'JIO  
*{HGLl|=  
private String sSiteURL; //Site's URL *sIi$1vHu  
private String sFilePath; //Saved File's Path h\Z3yAYd  
private String sFileName; //Saved File's Name hLu&lY  
private int nSplitter; //Count of Splited Downloading File o,iS&U"TC  
Z?5,cI[6#  
u!sSgx =  
public SiteInfoBean() M|5^':Y  
{//nSplitter的缺省值为5 ^w.k^U=B  
//default value of nSplitter is 5 VG? yL2y  
this("","","",5); A)=X?x  
} @oUf}rMiDa  
Lx9hq7<  
FA5k45w L  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) T9aTEsA[U  
{ '&rw=.cU  
sSiteURL= sURL; B(HNB\3u  
sFilePath = sPath; ch%Q'DR_I)  
sFileName = sName; 0:~gW#lD  
this.nSplitter = nSpiltter; J+-,^8)  
K+(m'3`  
c`Lpqs`  
} <h)deB+}  
rCV$N&rK  
LX&=uv%-^  
public String getSSiteURL() !H2C9l:rd  
{ '5&B~ 1&  
return sSiteURL; Ut0qr kqF  
} 37GHt9l  
&QiAM`MbC=  
/ n C$?w  
public void setSSiteURL(String value) :/I={)5  
{ pP=_@ 3 D  
sSiteURL = value; M)bC%(xJ  
} vq@#Be?@  
%t,1_c0w  
%a%+!wX0x  
public String getSFilePath() O% j,:t'"  
{ So3,Z'z=  
return sFilePath; D| 3AjzW  
} ?#');`  
oZ|{J  
Xmw2$MCB  
public void setSFilePath(String value) J~PTVR  
{ 0ll,V  
sFilePath = value; NpjsZcA  
} Br?++\  
~cWLu5  
Pj^k pjV  
public String getSFileName() ~8S4Kj)%  
{ U^WQWa  
return sFileName; 'Y6(4|w (  
} hNgcE,67q  
9 u6 g  
Y D1g]p  
public void setSFileName(String value) TU^tW  
{ QZeb+r  
sFileName = value; Tg}H < T  
} .-gm"lB  
LQuYCfj|  
B%?|br  
public int getNSplitter() (rCPr,@0  
{ pD)/- Dgdm  
return nSplitter; W"DxIy  
} s`dkEaS  
w^vK7Z 1$  
0o\=0bH&s  
public void setNSplitter(int nCount) J0{WqA.P  
{ G/^5P5y%@  
nSplitter = nCount; 2gNBPd)I  
} tF)k6*+  
} ^!{ oAzy9  
t2U]CI%  
e=NQY8?  
/* Z2Y583D  
**Utility.java wLg:YM"  
*/ RaJ }>e  
package NetFox; FkkZyCqZ`  
#6#BSZ E  
#gr+%=S'6C  
public class Utility { m/"=5*pA  
&dHm!b  
F'T= Alf  
public Utility() A1&>L9nUx  
{ 7Ohu$5\  
L< nkI  
A+Pm "|  
} m$G?e 9{  
2v; 7ohK  
//线程睡眠 D=Yag!1  
public static void sleep(int nSecond) Y_TL4  
{ "#"Fp&Z7  
try{ e&VR>VJEA  
Thread.sleep(nSecond); 0zk T8'v  
} c&iK+qvh{  
catch(Exception e) 4FP~+  
{ |'>E};D  
e.printStackTrace (); _S7M5{U_  
} clU3#8P!=  
} 9jJ/ RXp  
JCMEhI6d*  
//日志 >@92K]J  
public static void log(String sMsg) |<o>$;mZ  
{ RHA>fXp  
System.err.println(sMsg); WSX@0A.&)  
}  z]R!l%`  
U Edl"FwM4  
^_"q`71Dk  
public static void log(int sMsg) K^1O =1gY  
{ cbHn\m)J,  
System.err.println(sMsg); "5z6~dq  
} lr= !:D=K  
} F7PZV+\  
^zs4tCW%  
e"8m+]  
/* =xQfgj  
**TestMethod.java .TrQ +k>  
*/ "u> sS  
package NetFox; ucm.~1G(  
?;=Y1O7N(  
9Z_OLai  
public class TestMethod { 'V1 -iJj9  
UHDI9>G~,  
u:>3j,Cs  
public TestMethod() C%7,#}[U/  
{ ///xx/weblogic60b2_win.exe 9/qS*Zdh)  
try{ uL{~(?U$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ?@ye*%w_  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1RO gUJ;  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .j$bCKXGx  
fileFetch.start(); ("@V{<7(t  
} &_x/Dzu!z  
catch(Exception e){e.printStackTrace ();} _nCs$ U  
2/o/UfYjgF  
W;9X*I8f8  
} 'f<_SKd  
,f""|X5  
[LEh  
public static void main(String[] args) Hbj:CViYq  
{ #YMp,i  
new TestMethod(); <$Kv^Y*  
} \EfwS% P  
} blkJm9]v  
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