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http断点续传简单实现(java)

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/* )2sE9G,  
**SiteFileFetch.java yE&WGpT  
*/ B%7Az!GX  
package NetFox; ]J1oY]2~  
import java.io.*; 9epMw-)k  
import java.net.*; |`|#-xu  
#Z. QMWq  
8KyRD1 (-R  
public class SiteFileFetch extends Thread { hv0bs8h  
-1{f(/  
/S{U|GBB%r  
SiteInfoBean siteInfoBean = null; //文件信息Bean >^6|^rc  
long[] nStartPos; //开始位置 u{-@,-{  
long[] nEndPos; //结束位置 I q?n*P$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 bey:Qj??  
long nFileLength; //文件长度 nR]*RIp5  
boolean bFirst = true; //是否第一次取文件 :5sjF:@  
boolean bStop = false; //停止标志 8NkyT_\  
File tmpFile; //文件下载的临时信息 qRSoF04!R  
DataOutputStream output; //输出到文件的输出流 gvFJ~lL  
]]o?!NX  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) .mHVJ5^:4\  
public SiteFileFetch(SiteInfoBean bean) throws IOException `?{6L#  
{ GrUpATIx  
siteInfoBean = bean; KE.O>M ,I.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ppo.#p0w  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); - {}(U  
if(tmpFile.exists ()) 9u)p9)^-.v  
{ u6 QW*8b4  
bFirst = false; J&Db-  
read_nPos(); ^7uXpqQBr  
} 3:O|p[2)L  
else GEv x<:  
{ q*Oj5;  
nStartPos = new long[bean.getNSplitter()]; ;m7~!m)  
nEndPos = new long[bean.getNSplitter()]; Q;N)$Xx  
} a ~YrQI-@  
ow  
k')H5h+Q=  
VX*+:  
} |"PS e~ u  
NT2XG& $W>  
);T&pm:C>  
public void run() y #C9@C  
{ a x)J!I18  
//获得文件长度 n*ROlCxV  
//分割文件 Yecdw'BW?  
//实例FileSplitterFetch kL8 E#  
//启动FileSplitterFetch线程 2 FoLJ  
//等待子线程返回 .Tm.M7  
try{ 7NT0]j(w-  
if(bFirst) {\`y)k 7  
{ Qn|8Ic` *  
nFileLength = getFileSize(); H0 Z o.Np  
if(nFileLength == -1) t^Lb}A#$4  
{ U.V/JbXX  
System.err.println("File Length is not known!"); (, ik:j  
} \D k >dE&I  
else if(nFileLength == -2) VxS3lR=  
{ dl3;A_ 2  
System.err.println("File is not access!"); B|V!=r1%  
} ~ o2Z5,H  
else `mW~{)x  
{ XZ{rKf2  
for(int i=0;i<nStartPos.length;i++) ~(^pGL3<  
{ `#w#!@s#@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); #_x5-?3  
} "wcw`TsK  
for(int i=0;i<nEndPos.length-1;i++) ]b]J)dDI  
{ +}1zw<  
nEndPos = nStartPos[i+1]; TDbSK&w :s  
} Z9NND  
nEndPos[nEndPos.length-1] = nFileLength; \2=I//YF  
} b{,v?7^4  
} 63%V_B|  
 [B`4I  
u{va2n/  
//启动子线程 nS h~ mP  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; yH]Q;X '  
for(int i=0;i<nStartPos.length;i++) XkkzY5rxOc  
{ SPRTJdaC9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AX%}ip[PC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), h,B4Tg'  
nStartPos,nEndPos,i); &zB>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); S[q:b .  
fileSplitterFetch.start(); @k)J i!7  
} YmFg#eS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @[?ZwzY:9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); aem gGw<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n*ShYsc  
nEndPos = " + nFileLength); 2L;=wP2?{  
// fileSplitterFetch[nPos.length-1].start(); 'I+M*Iy  
nA_'j l  
^'`(E_2u  
//等待子线程结束 QEbf]U=  
//int count = 0; .)+c01  
//是否结束while循环 %qo.n v  
boolean breakWhile = false; *xpn-hCp<  
HfhI9f_x  
yA"?Hv\o;  
while(!bStop) IO9|o!&>  
{ h%$^s0w  
write_nPos(); GTTEg{  
Utility.sleep(500); !~%DR~^`  
breakWhile = true; EV Z1Z  
j!!s>7IZ  
k7rg:P  
for(int i=0;i<nStartPos.length;i++) xR%NiYNQz  
{  QtG6v<A  
if(!fileSplitterFetch.bDownOver) M&hNkJK*G  
{ 60{DR >S  
breakWhile = false; D8u`6/^  
break; N9#xTX  
} 'Ca;gi !U  
} &dWGa+e  
if(breakWhile) F1_,V?  
break; N0^SWA|S  
*A8*FX>\F  
,D }Ka?  
//count++; b(R.&X  
//if(count>4) i~v[3e9y7  
// siteStop(); WHv6E!^\_  
} |hi,]D^Kc  
R\&z3<-S  
M[z1B!rT  
System.err.println("文件下载结束!"); 56c[$ q  
} oVZzvK(zR  
catch(Exception e){e.printStackTrace ();} }PBL  
} !idVF!xG  
4XVwi<)  
|4pl}:g/Z  
//获得文件长度 PPySOkmS3  
public long getFileSize() >0ZG&W9  
{ GXD<X_[  
int nFileLength = -1; 9)S3{i6w  
try{ $MQ<QP  
URL url = new URL(siteInfoBean.getSSiteURL()); ~/JS_>e#6P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nIlTzrf6  
httpConnection.setRequestProperty("User-Agent","NetFox"); TW(X#T@Z6I  
ic!% }S?  
r_Ou\|jU  
int responseCode=httpConnection.getResponseCode(); y>E:]#F  
if(responseCode>=400) Vq-Kl[-|  
{ wN%lc3[/z2  
processErrorCode(responseCode); fB7Jx6   
return -2; //-2 represent access is error 2BF455e   
} -eh .Tk  
+L'Cbv="  
\*{MgwF  
String sHeader; <N~9=g3  
+UX~'t_'v  
&0bq3JGW  
for(int i=1;;i++) (=WYi~2v  
{ 3ww\Z8UeK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); |1A0YjOD  
//Utility.log(in.readLine()); |X XO0  
sHeader=httpConnection.getHeaderFieldKey(i); SYsO>`/ )  
if(sHeader!=null) L'KKU4zj  
{ p&<n_b  
if(sHeader.equals("Content-Length")) oO3 ^9?Z  
{ t$t'{*t( T  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); I;wxgWOP  
break; u$5.GmKm  
} n=~!x  
} [!3cWJCt  
else ?Q"<AL>Z  
break; y1}2hT0,  
} @f|~$$k=  
} <Dgf'Gr J  
catch(IOException e){e.printStackTrace ();} VCnf`wZB"  
catch(Exception e){e.printStackTrace ();} ^["D>@yIR  
)[ UYCx'  
9SA%'  
Utility.log(nFileLength); `DSFaBj,  
Ce}m$k  
f9Xa}*  
return nFileLength; ZRw^< +  
} ft@#[Bkx  
$'d,X@}8  
_D{FQRU<YD  
//保存下载信息(文件指针位置) Dt7z<1-)l  
private void write_nPos() xfX|AC  
{ @C[p?ak  
try{ >b0 Bvx-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); vNdX  
output.writeInt(nStartPos.length); Syl9j]  
for(int i=0;i<nStartPos.length;i++) <Tbl |9  
{ !h}Vz  
// output.writeLong(nPos); 0d:t=LKw)  
output.writeLong(fileSplitterFetch.nStartPos); ! ,H6.IH;S  
output.writeLong(fileSplitterFetch.nEndPos); #fx"tx6  
} ]Y->EME:W  
output.close(); C-,#t5eir  
} XJl 3\*  
catch(IOException e){e.printStackTrace ();} qJl DQc-  
catch(Exception e){e.printStackTrace ();} Mkt_pr  
} #a|r ^%D  
]0(ZlpT  
fo>_*6i74  
//读取保存的下载信息(文件指针位置) fh1-]$z`~  
private void read_nPos() `RURC"  
{ 9X#]Lg?b  
try{ , .=7{y~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); l`X?C~JhJ  
int nCount = input.readInt(); wXdt\@Qr  
nStartPos = new long[nCount]; *h5L1Eq  
nEndPos = new long[nCount]; `W1TqA  
for(int i=0;i<nStartPos.length;i++) Ho&f[T(  
{ z([HGq5  
nStartPos = input.readLong(); `@6y Wb:X  
nEndPos = input.readLong(); ZN'B @E=p  
} D^];6\=.i  
input.close(); *U8,Q]gS  
} T|(w-)mv  
catch(IOException e){e.printStackTrace ();} 4@ny%_/  
catch(Exception e){e.printStackTrace ();} [V;u7Z\r-  
} mmNn,>AO!  
hS%oQ)zvE  
dIQ3snG  
private void processErrorCode(int nErrorCode) Z%I 'sWOd  
{  aqi]5,  
System.err.println("Error Code : " + nErrorCode); &f)pU>Di  
} L0%W;m  
?AI`,*^  
)7E7K%:b,  
//停止文件下载 *J4 \KU  
public void siteStop() :V)=/mR  
{ c,G[Rk  
bStop = true; )U}`x }:,  
for(int i=0;i<nStartPos.length;i++) RO'b)J:j9  
fileSplitterFetch.splitterStop(); SU~ljAF4  
Wh%@  
)g U#[}6H  
} \x8'K  
} zx?|5=+!  
//负责部分文件的抓取 uCWBM  
**FileSplitterFetch.java /}d)g4\j  
*/ ,x[~|J!  
package NetFox; 2ryg3% +O  
NZXCaciG  
rPifiLl A>  
import java.io.*; JY D\VaW  
import java.net.*; 2aUE<@RU[  
)@ .0ai  
+KP&D.wIo  
public class FileSplitterFetch extends Thread {  y]ya.YG  
3X`N~_+  
-e+im(2D=  
String sURL; //File URL ]^QO ^{Sz  
long nStartPos; //File Snippet Start Position IfCa6g<&(  
long nEndPos; //File Snippet End Position \LM{.g zT  
int nThreadID; //Thread's ID 4(8BWP~.y2  
boolean bDownOver = false; //Downing is over  S^5Qhv  
boolean bStop = false; //Stop identical d}^hZ8k|  
FileAccessI fileAccessI = null; //File Access interface z&.F YGq}  
_=I&zUF  
_U~~[I  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException YE-}1&8  
{ )u=a+T  
this.sURL = sURL; mr XmM<  
this.nStartPos = nStart; 0T:U(5Y9  
this.nEndPos = nEnd; W3B:)<f  
nThreadID = id; &?APY9\.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ,Q+.kAh !G  
} 90a!_8o  
:-T[)Q+-3  
G=KXA'R)1.  
public void run() uNvdlY]  
{ 6{[ uCxxl  
while(nStartPos < nEndPos && !bStop) p!`S]\XEB  
{ OT3~5j1[  
lnrs4s Km  
}Y3*X: i7  
try{ j<d,7  
URL url = new URL(sURL); Ce@"+k+w  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); xL!@$;J  
httpConnection.setRequestProperty("User-Agent","NetFox"); VVi3g  
String sProperty = "bytes="+nStartPos+"-"; ])Z p|?Y  
httpConnection.setRequestProperty("RANGE",sProperty); M4L<u,\1s  
Utility.log(sProperty); V6^=[s R  
G~zP&9N|  
cnU()pd  
InputStream input = httpConnection.getInputStream(); X[1w(dU[  
//logResponseHead(httpConnection); 7vB6IF  
-b'/}zz  
d+IN-lR(  
byte[] b = new byte[1024]; ?p &Xf>K  
int nRead; 2;ac&j1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) mS &^xWPV  
{ cbv%1DT3  
nStartPos += fileAccessI.write(b,0,nRead); E-HK=D&W/  
//if(nThreadID == 1) 3q0S}<h al  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X->` ~-aj  
} L=kETJ:g  
gq&jNj7V  
Jr,**,wA  
Utility.log("Thread " + nThreadID + " is over!"); VI8/@A1Gv  
bDownOver = true; !+3nlG4cw  
//nPos = fileAccessI.write (b,0,nRead); 7Q # A  
} ?2Sm f  
catch(Exception e){e.printStackTrace ();} O`0\f8/.?  
} Md>9Daa~  
} Ew&|!d  
y6gaoj  
m/ngPeZ  
//打印回应的头信息 He  LW*  
public void logResponseHead(HttpURLConnection con) Lv:;}  
{ V_jGL<X|  
for(int i=1;;i++) 7$Pf  
{ GT-ONwVDq  
String header=con.getHeaderFieldKey(i); ~f?brQ?  
if(header!=null) ~R~MC(5N[  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); $qM&iI-l0  
Utility.log(header+" : "+con.getHeaderField(header)); :VlMszy}B3  
else `/o|1vv@_  
break; L#`X;:   
} !>6`+$=U  
} @{@)gE  
M~g@y$  
N'I9J?e Q  
public void splitterStop() fs8C ^Ik>~  
{ LN=#&7=$c  
bStop = true; sJm v{wM  
} HK`r9frn  
) {4$oXQ  
c"NGE  
} 5)p!}hWs  
]NY^0SqM  
L:Me  
/* r9~IR  
**FileAccess.java U DHMNubB  
*//文件访问(定位,写) 0D}k ^W  
package NetFox; g\@zQ^O?  
import java.io.*; cEEnR1  
2\G[U#~bi  
5[H1nC @C  
public class FileAccessI implements Serializable{ {hx=6"@  
eyG[1EEU  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 7h\U}!  
RandomAccessFile oSavedFile; 0B(Y{*QB  
long nPos; [V41 Gk  
vJuL+'[i  
2z9N/SyN  
public FileAccessI() throws IOException U6~79Hnt  
{ TR!7@Mu 3  
this("",0); Enqs|fkbN  
} {$v>3FG  
g>_d,#F  
gr4JaV  
public FileAccessI(String sName,long nPos) throws IOException gHVD,Jr  
{ /(Ryh6M  
oSavedFile = new RandomAccessFile(sName,"rw"); )h/Qxf  
this.nPos = nPos; 'UB"z{w%  
oSavedFile.seek(nPos); 6o]>lQ}  
} NzbHg p  
)7a 4yTg!~  
"Fqrk>Q~  
public synchronized int write(byte[] b,int nStart,int nLen) PAv<J<d  
{ 1f0maN  
int n = -1; <Sp>uhet1  
try{ qz|xow/ns@  
oSavedFile.write(b,nStart,nLen); 49dN~k=  
n = nLen; _cQhT  
} T_~xDQ`v  
catch(IOException e) =p#:v  
{ t&rr;W]  
e.printStackTrace (); `qa>6`\  
} \,yg@ R  
r+}<]?aT>-  
:A`jRe.  
return n; x!A5j $k0  
} $"`e^J9!!  
1Ewg_/R  
pcPRkYT[ M  
} 9,0}}3J  
'z">4{5  
N#7_)S[@0l  
/* KL8WT6!RZ  
**SiteInfoBean.java 'jBtBFzP-  
*/ p&3~n: Fo  
package NetFox; 5z 9'~Gfb  
_OR[RGy  
"nC=.5/$  
public class SiteInfoBean { r8[Ywn <u  
Ct}rj-L<i  
r%^XOw<'  
private String sSiteURL; //Site's URL <W88;d33r=  
private String sFilePath; //Saved File's Path kud2O>>  
private String sFileName; //Saved File's Name gYfOa`k  
private int nSplitter; //Count of Splited Downloading File M pLn)  
" {Nw K  
vz'<i. Yv4  
public SiteInfoBean() k1M?6TW&  
{//nSplitter的缺省值为5 $ 7uxReFZR  
//default value of nSplitter is 5 60%EmX ;  
this("","","",5); a: [m;  
} LZrkFkiC  
Kw,ln<)2  
f{f|frs  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) }o9(Q8  
{ gj1l9>f>]a  
sSiteURL= sURL; YX 19QG%  
sFilePath = sPath; O<6!?1|KP  
sFileName = sName; z;[Z'_B  
this.nSplitter = nSpiltter; =s[P =dU  
?&r >`H E  
RaY=~g  
} i+B tz-  
xm}`6B^f  
qAR}D~t  
public String getSSiteURL() cLCzLNyKl  
{ p4I6oS`/.  
return sSiteURL; ;gv9J [R  
} DSx D531[A  
vCtag]H2@  
j8#B  
public void setSSiteURL(String value) RBM4_L  
{ *`.4M)Ym~  
sSiteURL = value; ^)|1T#Tz  
} E>6:59+  
EL-1o0 2-  
FR@## i$  
public String getSFilePath() p&ml$N9fd  
{ >VWH bo  
return sFilePath; dsJHhsu6  
} 3xz{[5<p  
l<# *[TJ  
Oy/+uw^  
public void setSFilePath(String value) Nm]\0m0p-  
{ ;l6tZ]-"  
sFilePath = value; d>qxaX;  
} NP*M#3$[  
/K]<7  
`[5QouPV  
public String getSFileName() ,:QDl  
{ W8 m*co  
return sFileName; kf<5`8  
} e.IKmH]z  
i@M^9|Gh  
;eRYgC  
public void setSFileName(String value) xPi/nWl`|  
{ s$ 2@|;  
sFileName = value; *!*J5/ b  
} z2QZ;ZjvRS  
;9hi2_luV  
DEw_dOJ(  
public int getNSplitter() H `V3oS~}  
{ ?][2J  
return nSplitter; uI I:Y{G  
} bNG;`VZ%  
&&;ol}W  
|E)Es!dr  
public void setNSplitter(int nCount) v@0lTl_  
{ oiq7I@Y`x  
nSplitter = nCount; 89@e &h*  
} siHS@S  
} *kXSl73 k  
*8uSy/l  
DVNGV   
/* l*|^mx^Q  
**Utility.java < ealt  
*/ < }3c%Q1  
package NetFox; Fs_umy#  
o Ohm`7iy  
*@q+A1P7@  
public class Utility { V6,D~7  
Eg"DiI)7  
av(d0E}}b  
public Utility() _$me.  
{ )K8k3]y&  
Ds$8$1=L=k  
@xJ qG"  
} dUtxG ~9  
@+ VvZc2Y  
//线程睡眠 hv'~S  
public static void sleep(int nSecond) b'^OW  
{ {_1^ GIIS  
try{ BYEqTwhT&  
Thread.sleep(nSecond); \`#;J?Y|`F  
} ,@=qaU  
catch(Exception e) TR,,=3n  
{ z= -u89]  
e.printStackTrace (); zYdSg<[^  
} h'<}N  
} GV1\8OG7  
J p.Sow  
//日志 "_ b Sy  
public static void log(String sMsg) *$x/(!UE  
{ . ({aPtSt!  
System.err.println(sMsg); GBvB0kC)c  
} UM7Ft"  
* eL%[B  
EA2BN}  
public static void log(int sMsg) R:B-4  
{ ?6B)Ek,'X?  
System.err.println(sMsg); k+44ud.j  
} EuqmA7s8A  
} +&tY&dQQB  
\~Zj](#  
&by,uVb=|{  
/* 673v  
**TestMethod.java Y>EwU  
*/ fyx-VXu  
package NetFox; ?)1h.K1}M  
F&;g< SD  
"*#$$e53A  
public class TestMethod { YWM$%   
P6S^wjk  
a9"x_IVU  
public TestMethod() e}f!zA  
{ ///xx/weblogic60b2_win.exe WE4:Jy  
try{ B+ GPTQSTb  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); E@"+w,x)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Y:G6Nd VFM  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0gHJ%m9s  
fileFetch.start(); 5wRDH1z@{  
} Q <^'v>~n  
catch(Exception e){e.printStackTrace ();} B[C2uVEX:  
q+dY&4&u  
LcE!e%3  
} y .S0^  
]ss0~2  
f`p`c*  
public static void main(String[] args) 3w ?)H  
{ VGM8&J{o'  
new TestMethod(); =nA;,9%  
} %#02Z%?%  
} :doP66["!  
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