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http断点续传简单实现(java)

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/* z~th{4#E ;  
**SiteFileFetch.java y q!{\@-  
*/ MJA;P7g  
package NetFox; RB9ZaL\  
import java.io.*; $>zqCi2tB<  
import java.net.*; N<O<wtXIj  
iB}*<~`.Eg  
b"nD5r  
public class SiteFileFetch extends Thread { }LY)FT4n  
}J`cRDO  
O Cn  ra  
SiteInfoBean siteInfoBean = null; //文件信息Bean 9 /=+2SZ  
long[] nStartPos; //开始位置 i}O.,iH  
long[] nEndPos; //结束位置 G8.nKoHv7x  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 G0he'BR  
long nFileLength; //文件长度 ^vJy<  
boolean bFirst = true; //是否第一次取文件 Nj.;mr<  
boolean bStop = false; //停止标志 l(HxZlHr  
File tmpFile; //文件下载的临时信息 TU*Y?D L  
DataOutputStream output; //输出到文件的输出流 k#-%u,t  
2AW*PDncxP  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) {(l,Uhxl""  
public SiteFileFetch(SiteInfoBean bean) throws IOException CY\D.Eow  
{ Mzw:c#  
siteInfoBean = bean; m8 6ztP)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); F#~*j  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?1**@E0  
if(tmpFile.exists ()) 'A9Z ((  
{ >IipWTVo<  
bFirst = false; ?z0W1a  
read_nPos(); yG^pND>_df  
} `i!fg\qnK  
else V ONC<wC  
{ P5W58WxT'  
nStartPos = new long[bean.getNSplitter()]; -56gg^Pnr  
nEndPos = new long[bean.getNSplitter()]; aK8s0G!z?5  
} ,'n`]@0?\  
>2ha6A[  
2|&SG3e+(I  
ZcN#jnb0/  
} 2$'bOo  
{$V2L4  
n7|,b- <  
public void run() VI-6t"l  
{ dl(!{tZ#  
//获得文件长度 6#Rco%07zI  
//分割文件 RIDl4c [  
//实例FileSplitterFetch ZFX6 iAxd  
//启动FileSplitterFetch线程 e>P>DmlW  
//等待子线程返回 et/v/Hvw1  
try{ 8~F?%!X  
if(bFirst) >uYU_/y$2  
{ x.sC015Id  
nFileLength = getFileSize(); 6`X}Z'4.Ox  
if(nFileLength == -1) i v.G  
{ :x3xeVt Y  
System.err.println("File Length is not known!"); i0Rj;E=:]  
} !="8ok+  
else if(nFileLength == -2) y&V'GhW!dd  
{ P26"z))~d  
System.err.println("File is not access!"); tO?-@Qf/9<  
} i1K$~  
else f`iDF+h<6  
{ !JBj%|!  
for(int i=0;i<nStartPos.length;i++) u'^kpr`y  
{ MY^o0N  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ;0`IFtz  
} /!N=@z)  
for(int i=0;i<nEndPos.length-1;i++) cgO<%_l3`  
{ c& K`t  
nEndPos = nStartPos[i+1]; /&9R*xNST#  
} JIsi  
nEndPos[nEndPos.length-1] = nFileLength; n(i/jW~0w  
} rM? J40&.  
} M@Ti$=  
v57<b&p26  
F3t IJz>3  
//启动子线程 7* [  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; N( f0,  
for(int i=0;i<nStartPos.length;i++) QP<.~^ao  
{ zN=s]b=/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yMC6 Gvp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c|K:oi,z  
nStartPos,nEndPos,i); 2%*\XPt)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2XEE/]^  
fileSplitterFetch.start(); li{!Jp5]1b  
} C{+JrHV%h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TM|PwY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?<S fhjU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", QMy1!:Z&!  
nEndPos = " + nFileLength); [7NO !^  
// fileSplitterFetch[nPos.length-1].start(); ]]e>Jym  
+N'&6z0Wf  
Z:^ S-h  
//等待子线程结束 2H`>Kj  
//int count = 0; 3d,:,f|h  
//是否结束while循环 #hk5z;J5  
boolean breakWhile = false; Q3Y(K\  
dkqyn"^  
c?KIHZ0  
while(!bStop) \#IKirf?  
{ 3`)ej`  
write_nPos(); G&t|aY-   
Utility.sleep(500); 7#SfuZ0@  
breakWhile = true; x&"P^gh)  
p/G9P +?  
5m;BL+>YE  
for(int i=0;i<nStartPos.length;i++) GDb V y)&  
{ 6G}4KGQc  
if(!fileSplitterFetch.bDownOver) i|xz  
{ .&`apQD}  
breakWhile = false; QjD=JC+  
break; 1f'msy/  
} 6!N2B[9  
} A8o)^T(vJ  
if(breakWhile) i g .  
break; P s<k2  
5X9Lh_p  
8'NT_NPNb  
//count++;  FsQoQ#*  
//if(count>4) -f1lu*3\  
// siteStop(); [)kuu  
} +n$ruoRJh  
( uG; Q  
m&z(2yb1  
System.err.println("文件下载结束!"); ]h=5d09z  
} @= =)  
catch(Exception e){e.printStackTrace ();} n&DBMU  
} EXwU{Hl  
o wI:Qs_/4  
|68u4zK  
//获得文件长度 hztqZ:  
public long getFileSize() w9mAeGyE  
{ I$4>_D  
int nFileLength = -1; 'Sesh'2 /  
try{ X?;iSekI4  
URL url = new URL(siteInfoBean.getSSiteURL()); 1=C<aRZ b^  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b`% !\I  
httpConnection.setRequestProperty("User-Agent","NetFox"); O1wo KkfV  
jQ7-M4qO/  
==oJhB  
int responseCode=httpConnection.getResponseCode(); fL("MDt  
if(responseCode>=400) cd=K=P}p  
{ rq Uk_|Xa  
processErrorCode(responseCode); /0$405  
return -2; //-2 represent access is error 8TK*VOf`  
} gvD*^  
kP5G}Bp  
EziGkbpd@  
String sHeader; DrbjklcUU  
$o9@ ?2  
WBA7G  
for(int i=1;;i++) ^~6gkS }  
{ G \Nnw==v  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); d @ l  
//Utility.log(in.readLine()); p L^3*B.Nr  
sHeader=httpConnection.getHeaderFieldKey(i); `M. I.Z_  
if(sHeader!=null) k*!iUz{]  
{ +@H{H2J4  
if(sHeader.equals("Content-Length")) M{jq6c  
{ lN0u1)'2  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8R-;cBT  
break; 5uOz#hN  
} mdo$d-d&  
} 4sW~7:vU  
else cMoJHC,!  
break; -t>"s'kv  
} ]0[ot$Da6  
} Plhakngj  
catch(IOException e){e.printStackTrace ();} @K}h4Yok  
catch(Exception e){e.printStackTrace ();} ^zS;/%  
Bu+?N%CBi  
L6;'V5Mg72  
Utility.log(nFileLength); L GVy4D  
wZW\r!Us  
F?0Q AA  
return nFileLength; qZ +K4H  
} 4S[)5su  
^ 4Ff8Y  
x8~*+ j  
//保存下载信息(文件指针位置) i[ws%GfEv  
private void write_nPos() !_;J@B  
{ DL,]iJm  
try{ TIR Is1  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 12_ 7UWZ"  
output.writeInt(nStartPos.length); 8G9( )UF.  
for(int i=0;i<nStartPos.length;i++) %+<1X?;,Fq  
{ }$r]\v  
// output.writeLong(nPos); N93R(x)%  
output.writeLong(fileSplitterFetch.nStartPos); xU6dRjYhH9  
output.writeLong(fileSplitterFetch.nEndPos); yy&L&v'  
} K5\l (BB  
output.close(); UO!} 0'  
} e$JCak=  
catch(IOException e){e.printStackTrace ();} zr_L V_e  
catch(Exception e){e.printStackTrace ();} &A`,hF8  
}  Y(2Z<d  
Jf\`?g3#  
(0.JoeA`y  
//读取保存的下载信息(文件指针位置) R*XZPzg%  
private void read_nPos() IN;9p w  
{ `&xdSH  
try{ }UQ,B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); @LDs$"f9=  
int nCount = input.readInt(); " vc4QH$  
nStartPos = new long[nCount]; SBf=d<j 1)  
nEndPos = new long[nCount]; mV)t  
for(int i=0;i<nStartPos.length;i++) ;ceg:-Zqo  
{ l~Ka(*[!U  
nStartPos = input.readLong(); O=lRI)6w@e  
nEndPos = input.readLong(); u47`&\  
} ,8d&uR}x  
input.close(); 4FZ/~Y1}  
} H@~tJ\L  
catch(IOException e){e.printStackTrace ();} gs0`nysM#  
catch(Exception e){e.printStackTrace ();} $#3[Z;\  
} `Mcg&Mi~  
qPWf=s7!  
a" T+CA  
private void processErrorCode(int nErrorCode) &-JIXVd*R  
{ -S&9"=v  
System.err.println("Error Code : " + nErrorCode); a1u4v/Qu9  
} mH5>50H;  
Ggst s  
Wg,@S*x(  
//停止文件下载 CdPQhv)m  
public void siteStop() D%c^j9' 1  
{ UQ7La 7"  
bStop = true; n<<arO"cv  
for(int i=0;i<nStartPos.length;i++) vv<\LN0  
fileSplitterFetch.splitterStop(); p9mGiK4!  
Q)qJ6-R|HD  
DIWyv-  
} ,j\uvi(Y  
} v0tFU!Q%  
//负责部分文件的抓取 dLwP7#r  
**FileSplitterFetch.java qLc&.O.=  
*/ 4;gw&sFF  
package NetFox; ggYi7Wzsd  
F M YcZ+4  
rd$T6!I  
import java.io.*; d(R8^v/L  
import java.net.*; -vk/z+-^!  
,# .12Q!  
JP {`^c  
public class FileSplitterFetch extends Thread { jUR* |  
@H( 7Mt  
QtW e,+WWV  
String sURL; //File URL #N64ZXz_  
long nStartPos; //File Snippet Start Position :,R>e}lM  
long nEndPos; //File Snippet End Position :?m"kh ~  
int nThreadID; //Thread's ID C=U4z|Ym  
boolean bDownOver = false; //Downing is over 9f5~hBlo  
boolean bStop = false; //Stop identical 1&7?f  
FileAccessI fileAccessI = null; //File Access interface O:RN4/17  
Yl$ @/xAa  
l[m*csDk"  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException H1KXAy`&  
{ R[fQ$` M  
this.sURL = sURL; ,@ f|t&  
this.nStartPos = nStart; W$J.B!O  
this.nEndPos = nEnd; _FS #~z'j  
nThreadID = id; nU\.`.39 +  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0/fZDQH  
} v$(Z}Hg  
[Fk|m1i!  
B4+u/hkbh?  
public void run() u(? U[pe[  
{ Zu4CFX-4  
while(nStartPos < nEndPos && !bStop) B,Tv9(sv  
{ *-q &~  
]W~M?1 }  
H_Sv,lwz;c  
try{ P *PJ  
URL url = new URL(sURL); CL-?Mi=Uc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qf<o"B|_9  
httpConnection.setRequestProperty("User-Agent","NetFox"); '.S02=/  
String sProperty = "bytes="+nStartPos+"-"; w T_l>u  
httpConnection.setRequestProperty("RANGE",sProperty); 4 2-T&7k  
Utility.log(sProperty); f(!cz,y^\*  
xCT2FvX6  
d/$e#8  
InputStream input = httpConnection.getInputStream(); RF4B ]Gqd  
//logResponseHead(httpConnection); :6EX-Xyj  
pm i[M)D  
/~fu,2=7  
byte[] b = new byte[1024]; erTly2-SJ  
int nRead; 5xNOIOpDB  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) iS"6)#a72  
{ I|c?*~7*  
nStartPos += fileAccessI.write(b,0,nRead); 0QrRG$<4X  
//if(nThreadID == 1) R3)ccom  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); JnnxXj30,  
} yOb']  
mRGr+m  
nKtRJ,>  
Utility.log("Thread " + nThreadID + " is over!");  :fy,%su  
bDownOver = true; w Bm4~ ~_  
//nPos = fileAccessI.write (b,0,nRead); p}wysVB  
} X(DP=C}v9  
catch(Exception e){e.printStackTrace ();} 7*Zm{r@u  
} ,lFzL3'_0x  
} 'X/:TOk{W  
bmKvvq  
k][{4~z  
//打印回应的头信息 0%IZ -])  
public void logResponseHead(HttpURLConnection con) bun_R-  
{ /6\uBy"Xt  
for(int i=1;;i++) )fS6H<*  
{ EKsOj&ZiJ  
String header=con.getHeaderFieldKey(i); HAs/f#zAk6  
if(header!=null) 29|nt1Z  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); L/vw7XNrX  
Utility.log(header+" : "+con.getHeaderField(header)); N#R8ez`  
else GU Mf}y  
break; K!E\v4  
} p_apVm\t_  
} f6Y-ss;'  
F%%mcmHD#  
4ISIg\:c*  
public void splitterStop() pXh`o20I  
{ I!K-* AB  
bStop = true; uOKdb6]r6  
} /!/Pk'p=/  
\lDh"  
6ZjY-)h  
} MD,BGO?C  
9j5Z!Vsy  
A L |,\s  
/* w^3S6lK  
**FileAccess.java < mFU T  
*//文件访问(定位,写) puEu)m^  
package NetFox; n}4q2x"  
import java.io.*; 9~K+h/  
8hyX He  
^HI2Vp  
public class FileAccessI implements Serializable{ MBQ|*}+;  
YuzVh9jTI  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >I&s%4  
RandomAccessFile oSavedFile; 8Vt'X2  
long nPos; |&bucG=  
WBzPSnS2  
L` rrT   
public FileAccessI() throws IOException  Sb)}  
{ ~ySsv  
this("",0); ZR{YpLFQ  
} j``Ku@/x0  
8S[bt@v  
b!"FM/ %  
public FileAccessI(String sName,long nPos) throws IOException !)}z{,Jx  
{ cN\_1  
oSavedFile = new RandomAccessFile(sName,"rw"); 7s}F`fjKP  
this.nPos = nPos; 1h)K3cC  
oSavedFile.seek(nPos); %Z*)<[cIE0  
} v&f\ Jv7  
wg:\$_Og  
v9t'CMU  
public synchronized int write(byte[] b,int nStart,int nLen) @bnw$U`+  
{ &{q'$oF  
int n = -1; C!^;%VQ}d  
try{ =i/ r:  
oSavedFile.write(b,nStart,nLen); %?S[{ 4A&  
n = nLen; v+<4?]EJ  
} sdgI ,  
catch(IOException e) *r!qxiY= r  
{ 3z"%ht~;  
e.printStackTrace (); Sj8fo^K50  
} aan(69=jz  
p}X *HJq$  
5,Co(K  
return n; AF{@lDa1h  
} RyWfoLc  
jD6T2K7i  
+p]@b  
} 'S=eW_ 0/  
4>N ig.#   
: ' pK  
/* W(.svJUgb.  
**SiteInfoBean.java }C~9 ?Y  
*/ rvb@4-i>iI  
package NetFox; |H 5$VSw  
Z 2$S'}F  
MY(51)*  
public class SiteInfoBean { Jt?`(H  
|Fq\%y#  
0p\Kf(|E*6  
private String sSiteURL; //Site's URL IZd~Am3f  
private String sFilePath; //Saved File's Path scrss  
private String sFileName; //Saved File's Name izu_KBzy  
private int nSplitter; //Count of Splited Downloading File rDc$#  
c/(Dg$DbX  
 (8 /&  
public SiteInfoBean() -Gm}i8;  
{//nSplitter的缺省值为5 f67pvyy -  
//default value of nSplitter is 5 %PK(Z*>  
this("","","",5); :e}j$v F  
} 7sVO?:bj}  
P(L iH  
0]GenT"   
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ;YBk.} %  
{ 9h6siK(F  
sSiteURL= sURL; `vf]C'  
sFilePath = sPath; )E6E}  
sFileName = sName; ^Q!A4 qOQ  
this.nSplitter = nSpiltter; &u (pBr8B  
91k-os(4]  
h6tYy_(G  
} tC7 4=  
=>GGeEL  
`2q]ju  
public String getSSiteURL() &m TYMpA  
{ $ ]^Io)}f@  
return sSiteURL; ~P*{%=a  
} Ve40H6 Ox  
]2iEi`"[  
 SxX  
public void setSSiteURL(String value) _0Y?(}  
{ #aKUD  
sSiteURL = value; @CC 6 `D  
} Y{X%C\  
_) UnHp_^  
j`MK\*qmz  
public String getSFilePath() [Z!oVSCZD%  
{ Z)}2bJwA  
return sFilePath; 0}g~69Z1=  
} T?7++mcA  
t\n'Kuk`  
D\pX@Sx,v[  
public void setSFilePath(String value) V7 hO}  
{ t ^1uj:vD  
sFilePath = value; (:}}p}u  
} X0LC:0+  
: TqeVf  
X*&Thmee  
public String getSFileName() 9]I{GyH  
{ mCQ:< #  
return sFileName; }%0X7'  
} _gl1Qtv@rf  
9LOq*0L_:  
hF5(1s}e$  
public void setSFileName(String value) LK>;\BRe?  
{ TT&%[A+  
sFileName = value; d?/>Qqw:#  
} SPtx_+ Q)S  
K4OiKYq  
Mh@n>+IR  
public int getNSplitter() LeNSjxB  
{ z<9Llew^e  
return nSplitter; '7.4!I0'  
} +IlQZwm~  
-<(RYMk*)  
df&.!7_R`  
public void setNSplitter(int nCount) gy"<[N .?c  
{ 8,&Y\b`..  
nSplitter = nCount;  C8} ;,  
} | vxmgX)  
} nB4+*=$E+-  
#jPn7  
caV DV  
/* OLqynY  
**Utility.java ^szi[Cj  
*/ 9H+Q/Q*-a  
package NetFox; }|Bs|$q  
g3(LDqB'.  
^^*Ia'9   
public class Utility { ZM [Z9/S8  
ciFqj3JS  
0(o.[% Ye  
public Utility() h]j>S  
{ ;f} ']2  
!mUO/6Q hq  
4AKPS&k;  
} 6wZ)GLW[  
 eAG)+b  
//线程睡眠 $\PU Y8  
public static void sleep(int nSecond) \(r$f!`  
{ ; {v2s;  
try{  #J  
Thread.sleep(nSecond); f|~X}R  
} b|\dHi2F T  
catch(Exception e) bo@, B  
{ z8xBq%97us  
e.printStackTrace (); Wmx3@]<  
} +M<W8KF  
} 'c3'eJ0  
8fP TxvXqL  
//日志 2W#^^4^+  
public static void log(String sMsg) SnM^T(gtS3  
{ O9AFQ)u   
System.err.println(sMsg); Ep3I*bQ Y  
} aS~~*UHW  
5gb:,+  
uJ0Wb$%  
public static void log(int sMsg) }^^c/w_  
{ WADEDl&,'  
System.err.println(sMsg); js% n]$N  
} 0;hn;(V]"  
} QXgfjo  
u^W!$OfZpp  
Fqh./@o  
/* (B! DBnq  
**TestMethod.java <-,y0Y'  
*/ Q2F20b  
package NetFox; z:1t vG  
zV(aw~CbZ  
F_4Et  
public class TestMethod { _/Ay$l;F  
`g0^ W/ j  
k(_OhV_  
public TestMethod() DhD##5a  
{ ///xx/weblogic60b2_win.exe <5}j(jxz}  
try{ }c>vk  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Hx!eCTO:*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7U2B=]<e-  
SiteFileFetch fileFetch = new SiteFileFetch(bean); U} w@,6  
fileFetch.start(); s_e*jM1  
} ^)C#  
catch(Exception e){e.printStackTrace ();} ew]G@66  
7nP{a"4_  
y9w,Su2  
} }w8yYI  
NQqNBI?cr  
`,4@;j<^@  
public static void main(String[] args) Bx6,U4o*  
{ '`f+QP=`  
new TestMethod(); C &y 2I  
} m_,Jbf  
} cvhwd\  
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