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http断点续传简单实现(java)

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/* g{$&j*Q9  
**SiteFileFetch.java @F7QQs3  
*/ McnP>n  
package NetFox; m$J'nA  
import java.io.*; rI]:| k  
import java.net.*; `T9<}&=!  
]Wa,a T'  
n.l p ena  
public class SiteFileFetch extends Thread { d(a6vEL4  
bM^'q  
72-@!Z0e  
SiteInfoBean siteInfoBean = null; //文件信息Bean `hlyN]L  
long[] nStartPos; //开始位置 y+ :<  
long[] nEndPos; //结束位置 cDTDim1F  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 GW $iK@  
long nFileLength; //文件长度 <{-DYRiN  
boolean bFirst = true; //是否第一次取文件 F"23>3  
boolean bStop = false; //停止标志 v!`M=0k  
File tmpFile; //文件下载的临时信息 YgWnPp  
DataOutputStream output; //输出到文件的输出流 \iVYhl  
1<R \V  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) w\t{'  
public SiteFileFetch(SiteInfoBean bean) throws IOException tOko %vY8  
{ <1jiU%!w  
siteInfoBean = bean; 2N,*S   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); G8oQSo;D  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); \+Cp<Hv+  
if(tmpFile.exists ()) xD lC]loi7  
{ 8'cDK[L  
bFirst = false; 3YT _GW{  
read_nPos(); d'-^ VxO0  
} Dkdm~~Rr  
else <I|ryPU9{X  
{ jA]xpf6}  
nStartPos = new long[bean.getNSplitter()]; v5$zz w  
nEndPos = new long[bean.getNSplitter()]; -=qmYf  
} f CVSVn"o  
Yp ? 2<  
|R[m&uOib  
L,kF]  
} sU}e78mh  
\R#XSW,  
i([A8C_A  
public void run() mA>Pr<aV:  
{ Sdt @"6  
//获得文件长度 |]]fcJOBP  
//分割文件 xjX5PQu  
//实例FileSplitterFetch WD)[Ac[  
//启动FileSplitterFetch线程 Ql V:8:H$  
//等待子线程返回 er<~dqZ}]  
try{ (Pu*[STTT  
if(bFirst) /V*eAn8>  
{ tIvtiN6[|l  
nFileLength = getFileSize(); 3?}SXmA'@  
if(nFileLength == -1) |F=^Cu,  
{ 0CN .gu  
System.err.println("File Length is not known!"); W4|;JmT.r  
} QWP_8$Q  
else if(nFileLength == -2) 0 s 4j>  
{ ?D~uR2+Z  
System.err.println("File is not access!"); PHOW,8)dZh  
} FQ4rA 4  
else 0+H"$2/  
{ >%[W2L\'  
for(int i=0;i<nStartPos.length;i++) @O(\ TIg  
{ ``\H'^{B  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); HU'E}8%t6  
} FJ[(dGKeE  
for(int i=0;i<nEndPos.length-1;i++) a[JgR/E@x  
{ u@|yw)  
nEndPos = nStartPos[i+1]; #\M<6n{  
} EagI)W!s[  
nEndPos[nEndPos.length-1] = nFileLength; fAm2ls7c  
} lk'RWy"pw  
} $H 9xM  
C/$IF M<  
lwB!ti  
//启动子线程 s-DtkO  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; w])Sz*J  
for(int i=0;i<nStartPos.length;i++) &S{F"z  
{ KG?]MVXA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), T<?;:MO88  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >ylVES/V  
nStartPos,nEndPos,i); >9klh-f  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); doa$ ;=wg  
fileSplitterFetch.start(); Q7s1M&K  
} z(=:J_N  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =wQ=`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); LSs={RD2+p  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S&0x:VW  
nEndPos = " + nFileLength); p[$I{F*a  
// fileSplitterFetch[nPos.length-1].start(); {J]|mxo  
8 , =$>@u  
~E\CAZ  
//等待子线程结束 ^q6~xC,/  
//int count = 0; x{- caOH  
//是否结束while循环 +1y#=iM{  
boolean breakWhile = false; {xr]xcM'b  
@PI\.y_w  
(/Mc$V  
while(!bStop) 6 qq7:  
{ h Na<LZ  
write_nPos(); wVVe L$28  
Utility.sleep(500); AjS5  
breakWhile = true; oMVwId f  
j{PX ~/  
)<|TEp4r-  
for(int i=0;i<nStartPos.length;i++) Q&J,"Vxw  
{ : ?V;  
if(!fileSplitterFetch.bDownOver) ?-f>zx8O  
{ o6r4tpiR5  
breakWhile = false; `#]\Wnp~y  
break; Dn[1BWM/7  
} `4=b|N+b"  
} JjmL6(*ui  
if(breakWhile) ymzm x$o=  
break; YJy*OS_&  
HT&0i,`  
3%} Ma,  
//count++; cm]]9z_<  
//if(count>4) A>?fbY2n  
// siteStop(); oxzNV&D[{`  
} 7I|%GA_  
1mX*0>  
U,=K_oBAq  
System.err.println("文件下载结束!"); x6t;=  
} S|[UEU3FpB  
catch(Exception e){e.printStackTrace ();} GXfVjC31z  
}  g{%';  
 UyQn onS  
w.8~A,5}Dh  
//获得文件长度 'GFzI:Xr  
public long getFileSize() ]ok>PH]  
{  W 6~=?C  
int nFileLength = -1; Zx_m?C_2_  
try{ coWBKWF  
URL url = new URL(siteInfoBean.getSSiteURL()); !r|X6`g  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9<#D0hh$  
httpConnection.setRequestProperty("User-Agent","NetFox"); BUb(BzC  
ZwMw g t  
<-F"&LI{<  
int responseCode=httpConnection.getResponseCode(); =Wf@'~K0k"  
if(responseCode>=400) %gaKnT(|r  
{ QP#Wfk(C  
processErrorCode(responseCode); wLtTC4D  
return -2; //-2 represent access is error D}T, z  
} ]c)SVn$6  
BGX@n#:  
h,x]  
String sHeader; fDd!Mt  
ca =e_sg  
z7q2+;L  
for(int i=1;;i++) .6K>"  
{ o$O,#^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >-P0wowL  
//Utility.log(in.readLine()); K +~v<F  
sHeader=httpConnection.getHeaderFieldKey(i); k 3 l  
if(sHeader!=null) f[I c hCwX  
{ i.sq^]j  
if(sHeader.equals("Content-Length")) guv@t&;t0  
{ {<kG{i/  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); z(3"\ ^T  
break; akQH+j  
} vrzX%'  
} U3}R^W~eb  
else _ ^{Ep/ME=  
break; ]D%k)<YK  
} N-gRfra+8L  
} H#inr^Xa  
catch(IOException e){e.printStackTrace ();} E: GJ$I  
catch(Exception e){e.printStackTrace ();} S F>D:$a  
.jp]S4~  
X}(0y  
Utility.log(nFileLength); ^>Y%L(>  
&r%*_pX  
7g)3\C   
return nFileLength; ?N*0 S'dY  
} c~xo@[NaS  
` a>vPW  
>x4[7YAU{  
//保存下载信息(文件指针位置) n5.>;N.*  
private void write_nPos() (x qA.(F  
{ Jj:6 c  
try{ \w^QHX1+  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {ah=i8$  
output.writeInt(nStartPos.length); * Xoscc  
for(int i=0;i<nStartPos.length;i++) It4z9Gh  
{ R`2A-c  
// output.writeLong(nPos); L]d@D0.Z  
output.writeLong(fileSplitterFetch.nStartPos); N;'HR)  
output.writeLong(fileSplitterFetch.nEndPos); .gGvyscdH;  
} |A0$XU{  
output.close(); v9U(sEDq  
} 6;cY!  
catch(IOException e){e.printStackTrace ();} %i8>w:@NW  
catch(Exception e){e.printStackTrace ();} IY6_JGe_w  
} abeSkWUL(  
DYlvxF`  
:(>9u.>l?5  
//读取保存的下载信息(文件指针位置) -l H>8+  
private void read_nPos() mE`qvavP|/  
{ >&QH{!(  
try{ {X<4wxeTo  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); xn@0pL3B~  
int nCount = input.readInt(); *ldMr{s<R  
nStartPos = new long[nCount]; ]M;6o@hq  
nEndPos = new long[nCount]; q 9S z7_K  
for(int i=0;i<nStartPos.length;i++) .vS6_  
{ 1?|6odc  
nStartPos = input.readLong(); b$O_L4CP  
nEndPos = input.readLong(); vt@Us\fI  
} `t0f L\T  
input.close(); Q)`gPX3F  
} uxyTu2L7  
catch(IOException e){e.printStackTrace ();} H'{?aaK|t  
catch(Exception e){e.printStackTrace ();}  }m%?&c  
} `QdQ?9x{F  
rAWl0y_m  
+RV-VrV  
private void processErrorCode(int nErrorCode) xwnoZ&h  
{ ^Opy6Bqb  
System.err.println("Error Code : " + nErrorCode); neh;`7~5@K  
} H:-A; f!Z  
x$GsDV  
?[VpN2*  
//停止文件下载 8i;)|z7  
public void siteStop() ^ Wfgwmh  
{ IT`=\K/[4  
bStop = true; ^qO=~U!{  
for(int i=0;i<nStartPos.length;i++) !UoU#YU  
fileSplitterFetch.splitterStop(); [W$Z60?RR  
Hp}  
6_<s=nTX  
} c~UAr k S  
} $i:||L^8p  
//负责部分文件的抓取 ouVjZF@kS  
**FileSplitterFetch.java ; ,=h59`  
*/ F|?'9s*;6G  
package NetFox; :e]9T3Q  
wB>S\~i  
0[:9 Hb6  
import java.io.*; Ae j   
import java.net.*; 7grt4k  
Bw<zc=%  
x}&a{;  
public class FileSplitterFetch extends Thread { ?96-" l  
oU0 h3  
Vp $wHB&  
String sURL; //File URL ;DD>k bd  
long nStartPos; //File Snippet Start Position ("E!Jyc!  
long nEndPos; //File Snippet End Position ~sU?"V  
int nThreadID; //Thread's ID ) p<fL  
boolean bDownOver = false; //Downing is over AB"1(PbG  
boolean bStop = false; //Stop identical ZSPgci  
FileAccessI fileAccessI = null; //File Access interface ?,:#8.9  
!ml_S)  
?orhJS  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 5U{4TeUH  
{ -/UXd4S  
this.sURL = sURL; b>QM~mq3^I  
this.nStartPos = nStart; tyuk{* Me:  
this.nEndPos = nEnd; jefNiEE[  
nThreadID = id; - LiPHHX<  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8nIMZV  
} ^+.t-3|U  
OyJsz]b} M  
_7lt(f[S  
public void run() HX3D*2v":  
{ @1v3-n=  
while(nStartPos < nEndPos && !bStop) kz0I2!bt  
{ Y  .  
> X[|c"l.  
=!(*5\IM  
try{ X_u@D;$  
URL url = new URL(sURL); ;h9-}F  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); v._Egk0  
httpConnection.setRequestProperty("User-Agent","NetFox"); %9T~8L @.  
String sProperty = "bytes="+nStartPos+"-"; JFRpsv  
httpConnection.setRequestProperty("RANGE",sProperty); }UKgF.  
Utility.log(sProperty); \[hn]@@  
9DOkQnnc  
djsz!$  
InputStream input = httpConnection.getInputStream(); K/vxzHSl  
//logResponseHead(httpConnection); V(;55ycr  
m7r j>X Y  
W?qpnPW  
byte[] b = new byte[1024]; uw Kh  
int nRead; VY/|WD~"CW  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) }+Rgx@XZ\  
{ s, n^  
nStartPos += fileAccessI.write(b,0,nRead); EkJVFHfh  
//if(nThreadID == 1) *wC\w  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); /"""z=q  
} 2J;kD2"!  
tYs8)\{  
onnI !  
Utility.log("Thread " + nThreadID + " is over!"); t_jyyHxoZ:  
bDownOver = true; N[qA2+e$Z  
//nPos = fileAccessI.write (b,0,nRead); vG]GQ#  
} x37/cu  
catch(Exception e){e.printStackTrace ();} _urG_~q  
} c ]>DI&$;J  
} LH=d[3Y  
|7 &|>  
XkPv*%Er8  
//打印回应的头信息 EKZA5J7kn  
public void logResponseHead(HttpURLConnection con) |',M_ e]  
{ z,pNb%*O  
for(int i=1;;i++) -#LjI.  
{ CO-Iar  
String header=con.getHeaderFieldKey(i); /8xH$n&xoC  
if(header!=null) wgY6D!Y   
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 9p <:=T  
Utility.log(header+" : "+con.getHeaderField(header)); [34zh="o  
else 1ZT^)/G  
break; Wrmgu}q  
} u`'ki7LA  
} >M?H79fF2s  
!|:RcH[  
7\mDBG  
public void splitterStop() :?HSZocf  
{ %'N$l F"]  
bStop = true; !*&4< _  
} ,-@xq.D  
807al^s x  
sffhPX\I  
} -i#J[>=w{C  
@-0Fe9 n=  
9khjwt  
/* N99[.mErU  
**FileAccess.java ^_@r.y]  
*//文件访问(定位,写) = 0 ,|/1~  
package NetFox; ]?[zx'|  
import java.io.*; {'NBp0i  
"tqnx?pM  
YWEYHr;%^?  
public class FileAccessI implements Serializable{ 6`acg'sk>  
o`idg[l.  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 K[kds`  
RandomAccessFile oSavedFile; a$d:_,\ "  
long nPos; G.E[6G3  
7 0_}S*T  
Y?<)Dg.[  
public FileAccessI() throws IOException Gb;99mE  
{ z&O#v9.NE|  
this("",0); * -0>3  
} jh[ #p?:  
H"eS<eT  
13H;p[$  
public FileAccessI(String sName,long nPos) throws IOException <PX.l%  
{ z<!O!wX_aI  
oSavedFile = new RandomAccessFile(sName,"rw"); >Iuzk1'S  
this.nPos = nPos; {@3z\wMK$  
oSavedFile.seek(nPos); IroPx#s:i  
} J,??x0GDx,  
GWhE8EDT  
d PsLZ"I  
public synchronized int write(byte[] b,int nStart,int nLen) FQ`(b3.   
{ oB p3JX9_f  
int n = -1; >z(wf>2J  
try{ OZf6/10O/  
oSavedFile.write(b,nStart,nLen); OVZP x%a  
n = nLen; H9U .lb  
} oe9lF*$/  
catch(IOException e) V@[rf<,  
{ `{[RjM`  
e.printStackTrace (); SrFx_n  
} |d[5l^6  
Q=WySIF.  
lCR!:~  
return n; w9MoT.kI}  
} M ,`w A  
zEj#arSE4  
?E6^!4=,  
} qw<HY$3=  
/& r|ec5  
+"dv7  
/* KFU%DU G  
**SiteInfoBean.java V,Q4n%h1.  
*/ 6kN:*  
package NetFox; 0 Qnd6mb  
\9`#]#1bx5  
^XG*z?Tt  
public class SiteInfoBean { `<U5z$^QTw  
?F_)-  
H]&gW/=  
private String sSiteURL; //Site's URL 7VAJJv3  
private String sFilePath; //Saved File's Path b5<okICD  
private String sFileName; //Saved File's Name 22&;jpL'?  
private int nSplitter; //Count of Splited Downloading File lj4o#^lC  
.1#kD M  
iG#}`  
public SiteInfoBean() E"6X|I n  
{//nSplitter的缺省值为5 :Wc_Utt  
//default value of nSplitter is 5 Qs%B'9")  
this("","","",5); B2Z_]q$n*  
} rOcg+5  
MLr-, "gs  
,$N#Us(Wa  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `XJm=/f  
{ "j^MB)YD  
sSiteURL= sURL; dEp7{jY1O  
sFilePath = sPath; 2%]Z Kd  
sFileName = sName; ^nNitF  
this.nSplitter = nSpiltter; T]9m:z X9s  
[ *>AN7W   
[ c~kF+8  
} uOd& XW  
9AQxNbs  
=n+ \\D  
public String getSSiteURL() eTbg7"waA  
{ ,6{iT,~@8  
return sSiteURL; JeCg|@  
} v-Qmx-N  
wNYg$d0M  
__Nv0Ru  
public void setSSiteURL(String value) 69OF_/23  
{ E=$p^s  
sSiteURL = value; 2YlH}fnH  
} j.%K_h?V5  
H C0w;MG)  
-1u9t4+`  
public String getSFilePath() .4-,_`T?  
{ >/=> B7  
return sFilePath; \)/yC74r7(  
} !5Sd2<N  
y >+mc7n  
VUwC-)  
public void setSFilePath(String value) ;+/o?:AH  
{ Nd@~>&F  
sFilePath = value; M{mSd2  
} 4a''Mi`u  
:J/M,3  
NxA)@9Q  
public String getSFileName() Hy_;nN+e  
{ 4(8xjL:  
return sFileName; +&i +Mpb  
} &JP-O60  
gckI.[!b  
2%u;$pj  
public void setSFileName(String value) qfoD  
{ {d<;BLA  
sFileName = value; F?-R$<Cn2~  
} aZ|=(]  
5ZY<JA3  
= ieag7!  
public int getNSplitter() ~j9O$s~)  
{ =] C]=  
return nSplitter; c>"cX&  
} UVQ7L9%?f  
cyM-)r@YQV  
jMNU ?m:  
public void setNSplitter(int nCount) [U/(<?F{(  
{  ._O  
nSplitter = nCount; ACq7dLys,B  
} w= P 9FxB  
} L+}n@B  
Iw<i@=V  
{0"YOS`3AX  
/* *%/~mSx  
**Utility.java ^-z=`>SrS"  
*/ W ~f(::  
package NetFox; JM- t<.  
k%]=!5F  
GL{57  
public class Utility { /3B $(  
re?s.djT  
~{,X3-S_H  
public Utility() ig}A9j?]  
{ \p{5D`HY  
e]=lKxFh&l  
e [_m< e  
} qMt++*Ls  
R:Q0=PzDi#  
//线程睡眠 L2Pujk  
public static void sleep(int nSecond) uvP2Wgt  
{ 6(d}W2GP  
try{ Rp7ntI:  
Thread.sleep(nSecond); rE9I>|tX  
} 5NoI~X=  
catch(Exception e) =L;] ;i  
{ I`KQ|h0%  
e.printStackTrace (); w }^ I  
} ?`zXLY9q7  
} } :=Tm]S  
n_ lo`  
//日志 &e-U5'(6v_  
public static void log(String sMsg) r%:+$aIt  
{ 8{`?= &%6  
System.err.println(sMsg); 1$qh`<\  
} ,1OyN]f3  
c:Wze*vI ;  
GaX[C<Wt  
public static void log(int sMsg) g<{xC_J  
{ )q7UxzE+  
System.err.println(sMsg); m<FOu<y  
} 8#!i[UF dj  
} 5%sE] Y#  
xk&Jl#v  
{:@tQdM:i8  
/* w2_bd7Wp<  
**TestMethod.java b)(?qfXWP  
*/ ?v>ET2wD  
package NetFox; -46C!6a  
J+d1&Tw&  
hW!)w  
public class TestMethod { Z R/#V7Pj  
fd-q3 _f  
OO[F E3F  
public TestMethod() -'~ LjA(  
{ ///xx/weblogic60b2_win.exe b#7{{@H  
try{ S26MDLk`R3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~/.7l8)  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ]Oq[gBL"A  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .9Y)AtJTS  
fileFetch.start(); ~3uP6\F  
} 5j~$Mj`  
catch(Exception e){e.printStackTrace ();} .tD*2  
o,|[GhtHqs  
[1.+H yJ}  
} >4t+:Ut:  
UTXSeNP  
g8PTGz  
public static void main(String[] args) 0RoU}r@z4  
{ `ZC<W]WYX/  
new TestMethod(); EkziAON  
} pAT7)Ch  
} f bUr`~Y"  
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