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http断点续传简单实现(java)

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/* ZNpExfGEU  
**SiteFileFetch.java yL x .#kx6  
*/ vSC0D7BlG  
package NetFox; L2.`1Aag  
import java.io.*; .`>l.gmi&  
import java.net.*; Ij}F<ZgZG  
(e3Gs+;  
T) tZU?  
public class SiteFileFetch extends Thread { )]c3bMVE-  
s[2ZxCrCw  
EvqAi/(g  
SiteInfoBean siteInfoBean = null; //文件信息Bean Vy^yV|`v  
long[] nStartPos; //开始位置 5YI/Ec  
long[] nEndPos; //结束位置 uV}WSoq[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 q6JW@GT  
long nFileLength; //文件长度 W#jZRviyq!  
boolean bFirst = true; //是否第一次取文件 W({TC  
boolean bStop = false; //停止标志 -F+P;S  
File tmpFile; //文件下载的临时信息 t_>bTcsU  
DataOutputStream output; //输出到文件的输出流 sC5uA .?>9  
-N7L #a  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) koEX4q  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0SY f<$  
{ Z\=04[  
siteInfoBean = bean; v V6Lp  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); xJ2O4ob  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?(/j<,m^  
if(tmpFile.exists ()) yOUX E>-  
{ 2@R8P~^W  
bFirst = false; me:|!lI7YU  
read_nPos(); {#1j"  
} _m7U-;G  
else $TA6S+  
{ e@:P2(WW l  
nStartPos = new long[bean.getNSplitter()]; _h1 HuL  
nEndPos = new long[bean.getNSplitter()]; ^\[LrPq e  
} w~$c= JO#  
?#*  
D,dHP-v  
:Dk@?o@2;C  
} 88#qu.  
yD[zzEuQ  
^0Q=#p  
public void run() Q\27\2  
{ EO].qN-8  
//获得文件长度 X$-b oe?  
//分割文件 "s>fV9YyZ  
//实例FileSplitterFetch C '-zh\a  
//启动FileSplitterFetch线程 OHHNWg_5  
//等待子线程返回 aI={,\  
try{ 5"kx}f2$  
if(bFirst) S~k 0@  
{ nrTv=*tDj  
nFileLength = getFileSize(); h eE'S/  
if(nFileLength == -1) `&u<aLA  
{ [Y22Wi  
System.err.println("File Length is not known!"); Jm %ynW  
} %Ui{=920  
else if(nFileLength == -2) 8 _4l"v p  
{ 8 )mjy!,  
System.err.println("File is not access!"); -7I1Lh#M  
} F<yy>Wf  
else q}<.x8\  
{ 2#AeN6\@  
for(int i=0;i<nStartPos.length;i++) 7`b lGzP_  
{ }iua] 4 |  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); : F7k{~  
} b8N[."~:  
for(int i=0;i<nEndPos.length-1;i++) ).NcLJw_  
{ CJ9cCtA  
nEndPos = nStartPos[i+1]; Vl{~@G,@  
} 8"km_[JE e  
nEndPos[nEndPos.length-1] = nFileLength; c$Xe.:QY  
} (VYR!(17  
} DO&+=o`"  
83KfM!w  
NqJ<!q)  
//启动子线程 W!/vm  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Sc&)~h}YF  
for(int i=0;i<nStartPos.length;i++) 1z~k1usRK  
{ &GdL 9!hH  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =5y`(0 I`U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p-5P as  
nStartPos,nEndPos,i); 9W1;Kb|Z<  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T[0V%Br{d+  
fileSplitterFetch.start(); 5Noe/6  
} `*e4m  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  6R;)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W\it+/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", DeOXM=&z  
nEndPos = " + nFileLength); 1@A7h$1P  
// fileSplitterFetch[nPos.length-1].start(); -|m$YrzG  
xi6 80'  
owE<7TGPI?  
//等待子线程结束 |x &Z~y  
//int count = 0; XVQL.A7  
//是否结束while循环 ?^LG hdR  
boolean breakWhile = false; |EF>Y9   
b/}'Vf[  
<9ma(PFa  
while(!bStop) )K{o<m~WAo  
{ ;#3ekl{-g  
write_nPos(); uuu\f*<  
Utility.sleep(500); IWAj Mwo  
breakWhile = true; X_D6eYF  
f;.SSiT  
zzX<?6MS  
for(int i=0;i<nStartPos.length;i++) \Y*!f|=of  
{ |/@0~O(6  
if(!fileSplitterFetch.bDownOver) A)8rk_92Q  
{ qE>i,|rP`  
breakWhile = false; {bN Y  
break; 6 -]>]Hr-  
} SK's!m:r=  
} x.I][(}  
if(breakWhile) kr^0% A  
break; G9\EZ\x!  
'.pgXsC:=?  
__ 8&Jv\  
//count++; KzV.+f  
//if(count>4) FyCBN tCv  
// siteStop(); e\`wlaP,  
} z~F37]W3[  
{3_Gjb5\\4  
}A-{6Qe  
System.err.println("文件下载结束!"); mv{<'  
} M9gOoYf,~  
catch(Exception e){e.printStackTrace ();} y)P&]&"?  
} nt7|f,_J  
;:P7}v fz!  
d>Un J)V}  
//获得文件长度 R0{Qy*YQ`  
public long getFileSize() !6lOIgn  
{ ze&#i6S  
int nFileLength = -1; pg+b[7  
try{ 5`"iq "5Cf  
URL url = new URL(siteInfoBean.getSSiteURL()); Qe_+r(3)k  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2zhn`m  
httpConnection.setRequestProperty("User-Agent","NetFox"); \fTTkpM  
fTBVvY4(  
bV_j`:MD  
int responseCode=httpConnection.getResponseCode(); i&JpM] N  
if(responseCode>=400) C?/r;  
{ J2m"1gq,  
processErrorCode(responseCode); 22z1g(; @  
return -2; //-2 represent access is error DacN {r"3  
} yx2z%E  
YV-j/U{&  
(i\)|c/a7  
String sHeader; a~,Kz\Tt  
"9w}dQ  
fTcY"A,2  
for(int i=1;;i++) -OWZ6#v(  
{ ~Po<(A}`f  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4h;4!I|  
//Utility.log(in.readLine()); n,CD  
sHeader=httpConnection.getHeaderFieldKey(i); DY8(g=TI|1  
if(sHeader!=null) Yr=8!iR$  
{ GLCAiSMz[  
if(sHeader.equals("Content-Length")) rkq#7  
{ RB [/q:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [_V:)  
break; syR N4  
} iA9 E^  
} H37Qg ApB  
else 9:Si] Pp+S  
break; 19p8B&  
} uxb:^d?D!  
} "CBRPp  
catch(IOException e){e.printStackTrace ();} #BsW  
catch(Exception e){e.printStackTrace ();} 6x/s|RWL1  
}-74 f  
aZ6'|S;  
Utility.log(nFileLength); <6/= y1QC)  
KU]ok '  
Ps3~{zH`  
return nFileLength; gGEIK0\{  
} z3W3=@  
P3!Atnv2  
z6I%wh  
//保存下载信息(文件指针位置) d*2u}1Jo8  
private void write_nPos() NO2(vE  
{ Vc _:*  
try{ 6Cv.5V hx  
output = new DataOutputStream(new FileOutputStream(tmpFile)); IB8gDP2  
output.writeInt(nStartPos.length); TcJ$[  
for(int i=0;i<nStartPos.length;i++) ^&Q< tN 7  
{ E=]]b;u-n  
// output.writeLong(nPos); et` 0Je  
output.writeLong(fileSplitterFetch.nStartPos); 5]d{6Nc3P  
output.writeLong(fileSplitterFetch.nEndPos); )S*1C@  
} b# u8\H  
output.close(); f!x[ln<  
} >?I/;R.-  
catch(IOException e){e.printStackTrace ();} 5$%XvM  
catch(Exception e){e.printStackTrace ();} doR4nRl9  
} 0q#"clw  
n1,S_Hs  
L5f$TLw h;  
//读取保存的下载信息(文件指针位置) :RiF3h(  
private void read_nPos() JhP\u3 QE  
{ h&`y$Jj  
try{ _~&9*D$ {>  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); <^c3}  
int nCount = input.readInt(); lL0M^Nv  
nStartPos = new long[nCount]; 2"X~ju  
nEndPos = new long[nCount]; id?E)Jy  
for(int i=0;i<nStartPos.length;i++) OhFW*v  
{ "(f`U.  
nStartPos = input.readLong(); s$ z2 c  
nEndPos = input.readLong(); {$33B'wk  
} ^_W40/c3  
input.close(); 2khh4?|\  
} e;h,V(  
catch(IOException e){e.printStackTrace ();} RV;!05^<  
catch(Exception e){e.printStackTrace ();} :$ %>4+l  
} Qnt5HSSt  
`*_CElpP"  
pRrHuLj^  
private void processErrorCode(int nErrorCode) Z9[+'ZWt  
{ ]C!?HQ{bsf  
System.err.println("Error Code : " + nErrorCode); z:}nBCmLV  
} z_&P?+"Df  
S-c ^eLzQ  
}`_(<H  
//停止文件下载 2hq\n<  
public void siteStop() cP rwW 6  
{ vFhz!P~  
bStop = true; e.8$ga{  
for(int i=0;i<nStartPos.length;i++) 7u|B ](FS  
fileSplitterFetch.splitterStop(); wk @,wOt  
[_.n$p-  
24B<[lSK  
} iKAusWj  
} WD.U"YI8y  
//负责部分文件的抓取 `q_<Im%I  
**FileSplitterFetch.java !Z|($21W  
*/ qINTCm j  
package NetFox; izuF !9  
/{*$JF  
Ch5+N6c^  
import java.io.*; :NE/Ddgc'  
import java.net.*; f<=Fe:1.  
^$NJD  
6R4<J% $P  
public class FileSplitterFetch extends Thread { ^R~~L  
Q2QY* A  
n>FY?  
String sURL; //File URL e|lD:_1i  
long nStartPos; //File Snippet Start Position s&Yi 6:J  
long nEndPos; //File Snippet End Position 8ObeiVXf)  
int nThreadID; //Thread's ID  f^b K=#  
boolean bDownOver = false; //Downing is over ^sClz*%?  
boolean bStop = false; //Stop identical q>s`uFRg(  
FileAccessI fileAccessI = null; //File Access interface ,:GN;sIXg  
'*T]fND4  
LW:1/w&pv  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #/70!+J_UF  
{ (kw5>c7  
this.sURL = sURL; 93o;n1rS  
this.nStartPos = nStart; OH'ea5x q  
this.nEndPos = nEnd; @~:8ye  
nThreadID = id; mYv(R!37'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Z :nbZHByh  
} /nQ`&q  
s([dGD$i  
&JhX +'U  
public void run() DL8x":;  
{ @S3f:s0~D  
while(nStartPos < nEndPos && !bStop) Yj3I5RG  
{ XKU=oI0\j  
<<zI\+V  
)^x K   
try{ vhgLcrn  
URL url = new URL(sURL); {C3Y7<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3yO=S0`  
httpConnection.setRequestProperty("User-Agent","NetFox"); KoBW}x9Jp  
String sProperty = "bytes="+nStartPos+"-"; DuF"*R~et  
httpConnection.setRequestProperty("RANGE",sProperty); {hdPhL  
Utility.log(sProperty); ~Xv=9@,h  
`dW]4>`O  
w0J|u'H  
InputStream input = httpConnection.getInputStream(); \".^K5Pm  
//logResponseHead(httpConnection); zm#nV Y`  
 .\:J~(  
 $xgBKD  
byte[] b = new byte[1024]; \'v(Xp6  
int nRead; Z-X?JA\&  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) {?8B,G2r  
{ QP(BZJC  
nStartPos += fileAccessI.write(b,0,nRead); (z7+|JE.  
//if(nThreadID == 1) `/IKdO*!S  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q|(W-h+  
} kOrl\_!z3  
!0}\&<8/m  
WO*9+\[v  
Utility.log("Thread " + nThreadID + " is over!"); LKF/u` 0dP  
bDownOver = true; ^J/)6/TMXm  
//nPos = fileAccessI.write (b,0,nRead); zI;0&  
} WF2-$`x  
catch(Exception e){e.printStackTrace ();} 4P8*k[.  
} Jjm|9|C,  
} K[?Xm"4  
n1v5Q2xw  
g@ith&*=h  
//打印回应的头信息 [(mlv42"  
public void logResponseHead(HttpURLConnection con) 3iX?~  
{ ~mp0B9L%  
for(int i=1;;i++) uGP(R=H  
{ rofNZ;nu  
String header=con.getHeaderFieldKey(i); q_fam,9  
if(header!=null) }JgYCsF/f  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 8|g<X1H{M  
Utility.log(header+" : "+con.getHeaderField(header)); 8y2+&#$  
else dK9Zg,DZL  
break; !{%:qQiA  
} $jzFc!rs  
} hZ$t$3  
dp5cDF}l  
ku&k'V  
public void splitterStop() `` K#}3  
{ Xyx"A(v^l  
bStop = true; ~Ci{3j :]  
} iz[gHB  
MgMD\  
lS5ny  
} <i. a pBH  
{S.>BXX  
V"KS[>>f  
/* *%FA:Y  
**FileAccess.java %&<LNEiUN  
*//文件访问(定位,写) V-yUJ#f8[  
package NetFox; *f+: <=i  
import java.io.*; 8At<Wic  
}j {!-&  
t#E}NR  
public class FileAccessI implements Serializable{ Dt}rR[yJ  
_=XX~^I,  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %yS3&Ju  
RandomAccessFile oSavedFile; 3251Vq %  
long nPos; 1R%1h9I4'  
ro~+j}*   
.?W5{U  
public FileAccessI() throws IOException @z`@f"l  
{ JK_OZ  
this("",0); ))h6~1`  
} Yl cbW0'c  
1 OaXo!  
@* ust>7  
public FileAccessI(String sName,long nPos) throws IOException e /K#>,  
{ GIwh@4;  
oSavedFile = new RandomAccessFile(sName,"rw"); 8(U{2B8>\%  
this.nPos = nPos; ;3'NMk  
oSavedFile.seek(nPos); MjL)IgT  
} } ?@5W,  
Qx3eLfm  
\%jVg\4 '  
public synchronized int write(byte[] b,int nStart,int nLen) , \)a_@@k  
{ +>f<EPGn  
int n = -1; Q 9F)  
try{ W&Y"K)`  
oSavedFile.write(b,nStart,nLen); VyLH"cCv  
n = nLen; eDKxn8+(H  
} D@ek9ARAq  
catch(IOException e) I27,mS+]  
{ ' I}: !Z  
e.printStackTrace (); QCOo  
} .^(/n9|o-  
+C]&2zc.  
j{++6<tr  
return n; ?X$, fQ#F|  
} giY80!GX  
3INI?y}t   
<U Zd;e@  
} 7L5P%zLtB  
8T[ 6J{|C  
YNdrWBf)  
/* uzOYVN$t  
**SiteInfoBean.java Dh| w^Q  
*/ }GwVKAjP  
package NetFox; Ka!I`Yf  
I<oL}f  
>`RRP}u=u  
public class SiteInfoBean { Ut@RGg+f8  
>H][.@LyR  
\*T"M*;  
private String sSiteURL; //Site's URL 4vnUN  
private String sFilePath; //Saved File's Path I,@r5tK o  
private String sFileName; //Saved File's Name F0Jx(  
private int nSplitter; //Count of Splited Downloading File ChrY"  
OTWkUB{  
KxGX\   
public SiteInfoBean() {2d_"lHBt  
{//nSplitter的缺省值为5 $RX'(/  
//default value of nSplitter is 5 &n2e  
this("","","",5); "Y: /= Gx  
} l~:v (R5  
(46 {r}_O  
:;;E<74e i  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) DPgm%Xq9(!  
{ 6c4&VW  
sSiteURL= sURL; 1 k8x%5p  
sFilePath = sPath; 9Ru;`  
sFileName = sName; }Nj97 R  
this.nSplitter = nSpiltter; j1$8#/r;c  
RF}X ER  
|`k .y]9  
} < E|s\u  
<Q < AwP  
vYmSKS  
public String getSSiteURL() -F/st  
{ BcWcdr+}9  
return sSiteURL; `bI)<B  
} `1` f*d v  
<Cpp?DW_  
YB))S!;Ok  
public void setSSiteURL(String value) ^WYQ]@rh3  
{ QWnndI_4p  
sSiteURL = value; R@ Y=o].2  
} MZv]s  
ZM#=`k9  
_m E^rT  
public String getSFilePath() | $^;wP  
{ U 5w:"x  
return sFilePath; LHCsk{3  
} CBT>"sYE1  
5MTgK=c  
Lm*VN~2  
public void setSFilePath(String value) CJknJn3m&  
{ I+ l%Sn#\  
sFilePath = value; IakKi4(  
} `g ''rfk}  
!eR3@%4  
!cW[G/W8  
public String getSFileName() w FtN+  
{ 10[Jl5+t  
return sFileName; PaB!,<A  
} 8iQ[9  
L6P1L)  
mg:!4O$K  
public void setSFileName(String value) Tpp&  
{ `b5 @}',  
sFileName = value; @DAF 6ygs  
} ;Q0bT`/X  
#Doq P:  
;$j7H&UNQj  
public int getNSplitter() H5>hx {  
{ h&@R| N  
return nSplitter; ]uL +&(cr  
} &p UZDjo?  
X<OSN&d  
Q/>L_S  
public void setNSplitter(int nCount) *!e(A ]&  
{ `\| ssC8u  
nSplitter = nCount; )u ?' ;  
} d5I f"8`@  
} NVV}6TUV  
hPhZUL%  
.S\&L-{  
/* 0o&MB Dp  
**Utility.java W1aa:hEf  
*/ C.  MoKa3  
package NetFox; 1r)kR@!LNG  
YA(@5CZ  
8G%yB}pa  
public class Utility { )x,8D ~p'  
h #Z4pN8T3  
'rP]Nw  
public Utility() I8   
{ u0`o A  
%~ |HFYd  
"%2xR[NF  
} ~vdkFc(8B  
~q0*"\Ff  
//线程睡眠 4pz|1Hw7  
public static void sleep(int nSecond) }A$WO {2  
{ s Wjy6;  
try{ + bhym+  
Thread.sleep(nSecond); vdoZ&Tu  
} )wXuwdc[  
catch(Exception e) Eu<1Bse;  
{ Mq%,lJA\  
e.printStackTrace (); HHk)ZfWRo  
} 2i#Sn'1  
} (kBP(2V  
2Nc>6  
//日志 -5G)?J/*  
public static void log(String sMsg) :B *}^g  
{ ^ ?hA@{T/1  
System.err.println(sMsg); %%%fL;-y  
} Wk;5/  
Pj#'}ru!  
{y kYW%3s  
public static void log(int sMsg) XV>JD/K2  
{ YOyX[&oi  
System.err.println(sMsg); rPzQ8<  
} sPAg)6&M  
} 7[v%GoE  
+m\|e{G  
}peBR80tQ  
/* [Bb utGvj  
**TestMethod.java  Fnx`Ri  
*/ J<j&;:IRd  
package NetFox; dpZ;l 9  
9$K;Raz%  
?0*8R K  
public class TestMethod { I~eSZ?$s#  
Z-=YM P ]Q  
{C*\O)Gep  
public TestMethod() "7%:sty  
{ ///xx/weblogic60b2_win.exe omZO+=8Q  
try{ -PB[-CX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [^H"FA[  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); o(A|)c4k  
SiteFileFetch fileFetch = new SiteFileFetch(bean); '$|UwT`s  
fileFetch.start(); 8Q`WB0E<|  
} [jx0-3s:X  
catch(Exception e){e.printStackTrace ();} Zwt;d5U  
D6D1S/:ij'  
3-s}6<0v1  
} 9W*+SlH@ !  
>gtQw!  
>v;8~pgO  
public static void main(String[] args) :y]Omp  
{ Y[ reD  
new TestMethod(); H!e 3~+)  
} &`|:L(+  
} n ?[/ufl  
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