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http断点续传简单实现(java)

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/* q:D!@+U  
**SiteFileFetch.java ,`lVB#|  
*/ H _%yh,L  
package NetFox; VD*xhuy$k  
import java.io.*; ?NL>xMA  
import java.net.*; w/(hEF '  
]8i2'x  
j 4B|ktf  
public class SiteFileFetch extends Thread { ^YLpZoo  
}m6j6uAR6)  
=<M7t*!  
SiteInfoBean siteInfoBean = null; //文件信息Bean ]%K 8  
long[] nStartPos; //开始位置 pWwB<F  
long[] nEndPos; //结束位置 bl)iji`]  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  FGP~^Dr/  
long nFileLength; //文件长度 68^5X"OGF  
boolean bFirst = true; //是否第一次取文件 Dx-G0 KIG  
boolean bStop = false; //停止标志 q3s +?&  
File tmpFile; //文件下载的临时信息 t,2Q~ied=  
DataOutputStream output; //输出到文件的输出流 faVR %  
 j`9+pI  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) MFyMo  
public SiteFileFetch(SiteInfoBean bean) throws IOException z!={d1u#T  
{ Gv};mkX[N  
siteInfoBean = bean; aDik1Q  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); h*qoe(+ZD  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'e(`2  
if(tmpFile.exists ()) {|jG_  
{ zmxrz[  
bFirst = false; mQOYjy3  
read_nPos(); <A,G:&d~  
} :  Jh  
else W_zAAIY_Y  
{ _/)?GXwLn  
nStartPos = new long[bean.getNSplitter()]; (!nhU  
nEndPos = new long[bean.getNSplitter()]; XVfp* `  
} ?V}AwLX}  
^'|\8  
VvO/  
Wkk=x&  
} ~%4#R4&  
`j59MSuK  
VY'#>k} }  
public void run() A#mf*]'  
{ R{r0dK"_  
//获得文件长度 -IR9^)  
//分割文件 fN8|4  
//实例FileSplitterFetch 6 m5\f  
//启动FileSplitterFetch线程 ^Slwg|t*~P  
//等待子线程返回 #; I8 aMb  
try{ rs@,<DV)u  
if(bFirst) wovWEtVBU  
{ .Lrdw3(  
nFileLength = getFileSize(); /Xi:k  
if(nFileLength == -1) Kfc(GL?  
{ @|&P#wd.u  
System.err.println("File Length is not known!"); (U/xpj}  
} ;bd\XHwMUP  
else if(nFileLength == -2) 63QSYn,t  
{ a$I; L  
System.err.println("File is not access!"); $S$%avRX  
} Aa&3x~3+  
else 5Mb1==/R  
{ :~ 3/  
for(int i=0;i<nStartPos.length;i++) bQk5R._got  
{ r4O*0Q_  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ?-O(EY1E  
} ^/HE_keY  
for(int i=0;i<nEndPos.length-1;i++) 7581G$@ym  
{ RIUJ20PfYQ  
nEndPos = nStartPos[i+1]; :yvUHx  
} 5:f}bW*  
nEndPos[nEndPos.length-1] = nFileLength; 6^zuRY;  
} R|{6JsjG10  
} ]"^GRFK5  
(jCE&'?}  
EkV v  
//启动子线程 nX>k}&^L  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /Mf45U<  
for(int i=0;i<nStartPos.length;i++) L iJ;A*  
{ io:?JnQSA  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Gq;0j:?CC  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 6^['g-\2  
nStartPos,nEndPos,i); KhZ'Ic[vw  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7,|-%!p[  
fileSplitterFetch.start(); KoQvC=+WI  
} nF}]W14x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4;|&}Ij  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Arz> P@EQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", J?5O 2n  
nEndPos = " + nFileLength); _'Q}Y nEv  
// fileSplitterFetch[nPos.length-1].start(); :$[m[y7i  
?S!lX[#v  
F1?@tcr'  
//等待子线程结束 <4*7HY[  
//int count = 0; $$ \| 3rj!  
//是否结束while循环 0;e>kz3o  
boolean breakWhile = false; Cs%'Af  
Y&k'4Y%  
\J0gzi.  
while(!bStop) a+*|P  
{ 4MRHz{`wa  
write_nPos(); CN: 36  
Utility.sleep(500); <s-_ieW'  
breakWhile = true; ? Z8_(e0U  
av wU)6L  
RKIqg4>E  
for(int i=0;i<nStartPos.length;i++) WJe  
{ sBF}j.b  
if(!fileSplitterFetch.bDownOver) ImklM7A  
{ yYWGM  
breakWhile = false; Lc*i[J<s  
break; ^']xkS  
} rtf>\j+  
} `EU=u_N  
if(breakWhile) WABq6q!  
break; )1J&tV*U  
e|AJxn]  
j4H,*fc  
//count++; )F]E[sga  
//if(count>4) |? ?uVA)\X  
// siteStop(); 5`6@CRef  
} 2#6yO`?uo  
b)$<aFl  
E[2c`XFd8  
System.err.println("文件下载结束!"); &OGY?[n  
} QS_" fsyN:  
catch(Exception e){e.printStackTrace ();} X,x{!  
} ^7TM.lE  
=wU08}  
nd_d tsp#  
//获得文件长度 GR O[&;d`  
public long getFileSize() OMO.-p  
{ u Dm=W36  
int nFileLength = -1; &bs/a] ?Z7  
try{ ?K I_>{  
URL url = new URL(siteInfoBean.getSSiteURL()); 6/s#'#jh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R S;r  
httpConnection.setRequestProperty("User-Agent","NetFox"); .\{GU9|nO  
hXbb+j  
N$>g)Ml?  
int responseCode=httpConnection.getResponseCode(); vlm&)DIt  
if(responseCode>=400) "-A@>*g  
{ RjSVa.x  
processErrorCode(responseCode); #<4h Y7/  
return -2; //-2 represent access is error *Yl9%x]3c  
} "J%u !~  
<d$|~qS_  
LurBqr  
String sHeader; q%Obrk  
M<~z=B#  
~naL1o_FZ  
for(int i=1;;i++)  ];Bh1  
{ yXR$MT+~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ^C_Y[i ~|  
//Utility.log(in.readLine()); HWFo9as""v  
sHeader=httpConnection.getHeaderFieldKey(i); #{UM4~|:  
if(sHeader!=null) *hAq]VC})  
{ >F!2ib8  
if(sHeader.equals("Content-Length")) g G~UsA  
{ 4[Hf[.  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); qL,!  
break; f77Jn^Dt  
} EFqWnz  
} &JtK<g  
else -+#\WB{AI  
break; <8+.v6DCd  
} C:0Ra^i ?L  
} DE^{8YX,  
catch(IOException e){e.printStackTrace ();} +VI2i~  
catch(Exception e){e.printStackTrace ();} vv"_u=H  
#l+U(zH:JG  
,g 6w2y7 ]  
Utility.log(nFileLength);  $3W[fC  
k^S=i_ U  
bh3}[O,L A  
return nFileLength; u! x9O8y  
} ,N?~je.  
o[O-|XL_  
/F4rbL^:  
//保存下载信息(文件指针位置) iaLsIy#h  
private void write_nPos() y5RcJM  
{ /al(=zf  
try{ xCEEv5(5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M0S}-eXc5  
output.writeInt(nStartPos.length); (w-z~#<  
for(int i=0;i<nStartPos.length;i++) o(u&n3Q'  
{ 4=%Uv^M  
// output.writeLong(nPos); (UA a  
output.writeLong(fileSplitterFetch.nStartPos); m3+MRy 5  
output.writeLong(fileSplitterFetch.nEndPos); V&eti2 &zO  
} B= jJ+R  
output.close(); .Xc, Gq{  
} 6p1\#6#@  
catch(IOException e){e.printStackTrace ();} =%%\b_\L  
catch(Exception e){e.printStackTrace ();} | Z0?  
} |ITp$  _S  
hJ (Q^Z  
S1E =E5  
//读取保存的下载信息(文件指针位置) _*>bf G  
private void read_nPos() _[<R<&jG  
{ |h\e(_G \  
try{ 'nz;|6uC  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1`^l8V(  
int nCount = input.readInt(); d(3F:dbk  
nStartPos = new long[nCount]; =;W"Pi;*  
nEndPos = new long[nCount]; v~H1Il_+  
for(int i=0;i<nStartPos.length;i++) '_lyoVP  
{ 1XSA3;ZEc  
nStartPos = input.readLong(); XZEawJ0  
nEndPos = input.readLong(); "o 2p|2c  
} GpMKOjVm|  
input.close(); `MA ee8u'  
} HgvgO\`]  
catch(IOException e){e.printStackTrace ();} gbsRf&4h  
catch(Exception e){e.printStackTrace ();} @zL)R b%P$  
} ! @{rk p  
"w9LQ=mW  
vIF=kKl9,  
private void processErrorCode(int nErrorCode) Sf);j0G,D  
{ )@09Y_9r  
System.err.println("Error Code : " + nErrorCode); F[<EXLQ  
} Y9Q-<~\z  
SpPG  
,24NMv7  
//停止文件下载 zl F*F8>m  
public void siteStop() ([R}s/)$  
{ 1+~JGY#   
bStop = true; bZHuEh2w  
for(int i=0;i<nStartPos.length;i++) 8c(}*,O/  
fileSplitterFetch.splitterStop(); bW(+Aw=O  
,d(F|5 M:  
M$DJ$G|Z  
} {hGr`Rh  
} +c.A|!-  
//负责部分文件的抓取 l=8)_z;~D  
**FileSplitterFetch.java 9uV/G7Geq  
*/ *:J#[ET,  
package NetFox; xphw0Es  
Q/m))!ikMt  
7}OzTup  
import java.io.*; %_0,z`f  
import java.net.*; k_/hgO  
{_0Efc=7  
WMnR+?q  
public class FileSplitterFetch extends Thread { JZ  Qkr  
] e!CH <N  
'@>FtF[Gu  
String sURL; //File URL Rp `JF}~o  
long nStartPos; //File Snippet Start Position "D}PbT[V  
long nEndPos; //File Snippet End Position a\S"d  
int nThreadID; //Thread's ID DQ :w9  
boolean bDownOver = false; //Downing is over )f-ux5  
boolean bStop = false; //Stop identical jCDZ$W89  
FileAccessI fileAccessI = null; //File Access interface >^LVj[.1  
D M(WYL{  
_P 0,UgZz  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException F, Y@  
{ +Mc kR  
this.sURL = sURL; vpcHJ^19  
this.nStartPos = nStart; rUEoz|e4a  
this.nEndPos = nEnd; ^"7tfo8  
nThreadID = id; d af$`  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -ZFeE[Z  
} ("0@_05OH  
dya]^L}fL  
T=35?   
public void run() 9w'3d @  
{ xoF]r$sC8  
while(nStartPos < nEndPos && !bStop) -fw0bL%0  
{ h>-JXuN  
4r ;!b;3  
}M'h 5x  
try{ q$z#+2u  
URL url = new URL(sURL); #gq4%;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); RBIf6oxdE  
httpConnection.setRequestProperty("User-Agent","NetFox"); 2  *IF  
String sProperty = "bytes="+nStartPos+"-"; OLJb8kO  
httpConnection.setRequestProperty("RANGE",sProperty); K-IXAdx  
Utility.log(sProperty); ;v'7l>w3\w  
hYMIe]kJ  
;<`F[V Zau  
InputStream input = httpConnection.getInputStream(); I'2:>44>I6  
//logResponseHead(httpConnection); =A={ Dpv[>  
C`+g:qT  
pA%XqG*=Y  
byte[] b = new byte[1024]; <9 lZ%j;  
int nRead; $3S6{"  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) j89|hG)2  
{ tRRPNY  
nStartPos += fileAccessI.write(b,0,nRead); kKVd4B[#*  
//if(nThreadID == 1) %[\: 8  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); T0s7aw[zm  
} F+,X%$A#?  
Kdh(vNB>  
TJ[C,ic=D  
Utility.log("Thread " + nThreadID + " is over!"); Y,RED5]t  
bDownOver = true; }3:DJ(Y  
//nPos = fileAccessI.write (b,0,nRead); *#1&IJPI  
} >C y  
catch(Exception e){e.printStackTrace ();} 0l3v>ty  
} 9;2PoW8  
} jT"P$0sJAd  
WXu:mv,'e  
eT1b88_  
//打印回应的头信息 `}.K@17  
public void logResponseHead(HttpURLConnection con) h=SQ]nV{  
{ } [}u5T`w>  
for(int i=1;;i++) m6^Ua  
{ @*q WV*$h  
String header=con.getHeaderFieldKey(i); v'Ce|.;  
if(header!=null) *F*c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D5fJuT-bp  
Utility.log(header+" : "+con.getHeaderField(header)); W/ZmG]sZE  
else H=] )o2 1  
break; !R;P"%PHV  
} '#$Y :/  
} C\Q3vG  
jcHs!   
<J-bDcp  
public void splitterStop() 6TJ5G8z_  
{ &B^#? vmO  
bStop = true; <GPL8D  
} ~R/w~Kc!/A  
$V-]DD%Y  
r_p9YS@I  
} r9z_8#cR  
6~zR(HzV{  
}HtP8F8!x  
/* w{k8Y?  
**FileAccess.java 5,`U3na,  
*//文件访问(定位,写) EJ{Z0R{{  
package NetFox; Ze ~$by|9f  
import java.io.*; B+S &vV  
kB1]_v/  
DfwxPt#  
public class FileAccessI implements Serializable{ (1H_V(  
9 \i;zpN\  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 q"ba~@<BEl  
RandomAccessFile oSavedFile; KK4>8zGR  
long nPos; 1rh\X[@  
Onb*nm  
 hh<5?1  
public FileAccessI() throws IOException +*'  
{ J XKps#,(#  
this("",0); _?>!Bz m  
} (1JZuR<?c  
3 lH#+@  
7 vUfA"  
public FileAccessI(String sName,long nPos) throws IOException c_clpMx=  
{  v'i"Q  
oSavedFile = new RandomAccessFile(sName,"rw"); w,TyV%b[_  
this.nPos = nPos; !+Z"7e nj  
oSavedFile.seek(nPos); A Ntp7ad  
} X<@ytHBv  
6 GX'&z  
N[X%tf\L]F  
public synchronized int write(byte[] b,int nStart,int nLen) rg+28tlDn  
{ S!.aBAW  
int n = -1; #n%?}  
try{ nN>D=a"&F  
oSavedFile.write(b,nStart,nLen); 1Lz`.%k`:  
n = nLen; o/buU{)y  
} zOYkkQE3mJ  
catch(IOException e) F48:mfj1r  
{ G}ElQD  
e.printStackTrace (); |57KTiiNLI  
} /{YUM~  
>0)E\_ u  
@v_E' 9QG^  
return n; w8:F^{  
} 5~k-c Ua  
:}x\&]uC#k  
i,rP/A^q  
} Y<TlvB)w  
ONJW*!(  
X@Eq5s  
/* ,{ CgOz+Ul  
**SiteInfoBean.java VOwt2&mZ  
*/ ?2[=llS4  
package NetFox; fOiLb.BW  
T~8` {^  
AbUU#C7  
public class SiteInfoBean { 8OH<ppi  
ASY uZ  
6CO>Tg:%  
private String sSiteURL; //Site's URL KIn^,d0H  
private String sFilePath; //Saved File's Path y$s}-O]/-  
private String sFileName; //Saved File's Name L`FsK64@  
private int nSplitter; //Count of Splited Downloading File M['25[  
<y'B !d#  
jjBcoQU$o  
public SiteInfoBean() gXI_S9 z  
{//nSplitter的缺省值为5 v}A] R9TY  
//default value of nSplitter is 5 d hiLv_/  
this("","","",5); yd "|HHx  
} $m:}{:LDCf  
U#G uB&V  
S1uW`zQ!+_  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) *7oPM5J|v  
{ mkYM/*qyM&  
sSiteURL= sURL; I'"*#QOX  
sFilePath = sPath; ar+mj=m  
sFileName = sName; 9bgKu6-X  
this.nSplitter = nSpiltter; C yC<{D+  
FMY r6/I  
oV ?tp4&  
} ~cSC-|$^&  
!Y=s_)X  
C fQj7{  
public String getSSiteURL() +f\tqucI3  
{ Zm%}AzM  
return sSiteURL; e;x`C  
} GW'=/ z7  
6v GcM3M  
Xfx(X4$9  
public void setSSiteURL(String value) }@@1N3nnxV  
{ H:U1#bQQ:  
sSiteURL = value; ;G!X?(%+  
} meR%);\  
v|_?qBs"  
X X{:$f+  
public String getSFilePath() 2t1WbP1  
{ v0X5`VV  
return sFilePath; IaE};8a8  
} OW)8Z 60  
aO "JT  
6BW-AZc  
public void setSFilePath(String value) |F<U;xV$p  
{ }n=Tw92g  
sFilePath = value; .)|jBC8|}  
} Y8.0R-:ZAN  
$>/J8iB  
%P_\7YBC>  
public String getSFileName() 'Twi @I  
{ C,]Q/6'>  
return sFileName; qTqvEa^X`  
} N<Bi.\XC  
dcU|y%k%  
'BAe>r_Pn  
public void setSFileName(String value) po=*%Zs*T  
{ >~BU<#  
sFileName = value; F xFK  
} K!|=)G3.`  
e hxtNjA  
;oh88,*'  
public int getNSplitter() Q C~~  
{ "4g1I<  
return nSplitter; 1{o CMq/v  
} -# <,i '  
z-7F,$  
P%Q}R[Q  
public void setNSplitter(int nCount) i=o>Bl@f  
{ 2_r}4)z  
nSplitter = nCount; NWCnt,FlY  
} l[ @\!;|  
} ,)]ZD H  
ys+?+dY2  
#l;Ekjfz  
/* 6ap,XFRMh  
**Utility.java z@~1e]%  
*/ < ]wN/B-8J  
package NetFox; /unOZVr(  
Q2 rZMK  
m 7 Fz&bN  
public class Utility { )QBsyN<x6  
*tRJ=  
"45BOw&72G  
public Utility() u8o7J(aQsR  
{ 9\Xl 3j!  
3M1(an\nW  
e1<28g  
} "a,Tc2xk  
Y%=A>~s*c:  
//线程睡眠 WR'A%"qBwi  
public static void sleep(int nSecond) 'c &Bmd40  
{ +bRL.xY  
try{ =PZs'K  
Thread.sleep(nSecond); gLpWfT29V  
} oAvJ"JH@i  
catch(Exception e) oR-_=U^  
{ t9K.Jc0  
e.printStackTrace (); zv0RrF^  
} 2tWUBt\,g  
} H>DJ-lG(  
N_gjOE`x5  
//日志 (Nik( Oyj"  
public static void log(String sMsg) 40g&zU-  
{ l}O`cC  
System.err.println(sMsg); 3\(s=- vh  
} /itO xrA  
.}Zmqz[  
`Z@wWs  
public static void log(int sMsg) ,E>VYkoA  
{ ;m`I}h<  
System.err.println(sMsg); }kOhwT8sI  
} klch!m=d  
} J2 5>t^  
(nE$};c<b2  
CJu;X[6  
/* fA 3  
**TestMethod.java yS3x))  
*/ Sl$dXB@  
package NetFox; \C<rg|  
}`_2fJ6  
"lz!'~im  
public class TestMethod { yTDoS|B+)  
"(C }Dn#  
e<C5}#wt  
public TestMethod() /FYa{.Vlr  
{ ///xx/weblogic60b2_win.exe qp{NRNkQ  
try{ ;3?M?E/$s  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); R K'( {1  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); r{<u\>6X>P  
SiteFileFetch fileFetch = new SiteFileFetch(bean); #%{\59/w  
fileFetch.start(); 9J|YP}%  
} G2jEwi  
catch(Exception e){e.printStackTrace ();} 7 1)#'ey  
t]@ Zd*  
yNDyh  
} @+{S-iD"  
uY;/3 ?k&  
/kJ*WA?J  
public static void main(String[] args) a)TNVm^  
{ VJ$C)0xQA  
new TestMethod(); gai?LXM l}  
} #Se  
} /=3g-$o{`  
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