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http断点续传简单实现(java)

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/* d>wpG^"w  
**SiteFileFetch.java d&x #9ka  
*/ ,ej89  
package NetFox;  d  H ;  
import java.io.*; x Rp;y*  
import java.net.*; " R5! VV  
>K@Y8J+ e#  
lB< kf1[  
public class SiteFileFetch extends Thread { N\nxo0sl  
OciPd/6  
KM:k<pvi  
SiteInfoBean siteInfoBean = null; //文件信息Bean 8TH fFL  
long[] nStartPos; //开始位置 >oHgs  
long[] nEndPos; //结束位置 Q?xCb  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 q,% lG$0v  
long nFileLength; //文件长度 g-8D1.U  
boolean bFirst = true; //是否第一次取文件 (/;<K$u*h  
boolean bStop = false; //停止标志 B(t`$mC  
File tmpFile; //文件下载的临时信息 AC}[Q p!  
DataOutputStream output; //输出到文件的输出流 vP. ^j7wB  
\&jmSa=]l  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) pj9*$.{  
public SiteFileFetch(SiteInfoBean bean) throws IOException NQu .%=  
{ (aUdPo8H^  
siteInfoBean = bean; M7PG s-l  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); D~T;z pS  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); l6~wm1vO  
if(tmpFile.exists ()) A}l+BIt  
{ ui .riD[,O  
bFirst = false; Q| _e=  
read_nPos(); ,u@Vi0  
} ]Dd}^khv  
else b uOpHQn  
{ *Ud=x^JxO  
nStartPos = new long[bean.getNSplitter()]; Ucqn 3&  
nEndPos = new long[bean.getNSplitter()]; /<e<-C*d&<  
} (Z |Nz*<  
: pkOZ+t  
z?M_Cz;:J  
sogdM{tz\  
} *P; cSx?2  
Vm]xV_FOd  
[~Vj(H=KwI  
public void run() $Le|4Hj  
{ \NF5)]:  
//获得文件长度 {W11+L{8  
//分割文件 aUYq~E tj  
//实例FileSplitterFetch GC3WB4iY@U  
//启动FileSplitterFetch线程  SCq:jI  
//等待子线程返回 }v4T&/vt-  
try{ <_>xkQbn2  
if(bFirst) \C&V)/  
{ 6+LBs.vl}  
nFileLength = getFileSize(); f=T-4Of  
if(nFileLength == -1) w,!IvDCAw  
{ Y2d(HD@  
System.err.println("File Length is not known!"); m4_ZGjmJM  
}  sg9  
else if(nFileLength == -2) z~($ "  
{ g/(3D  
System.err.println("File is not access!"); q445$ndCT  
} Z!foD^&R  
else #gcv])to  
{ \u$[$R5  
for(int i=0;i<nStartPos.length;i++) FnWN]9  
{ M;j)F  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ]rS:# LK  
} WvN{f*  
for(int i=0;i<nEndPos.length-1;i++) $, vX yZ  
{ e.Gjp {  
nEndPos = nStartPos[i+1]; (8td0zq  
} ]WvV*FL9D3  
nEndPos[nEndPos.length-1] = nFileLength; S>;+zVF]  
} ,TlYQ/j%h  
} 1haNpLfS>  
o XFo  
epGC Ta  
//启动子线程 IcJQC  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; PdqyNn=  
for(int i=0;i<nStartPos.length;i++) ZE:!>VXa87  
{ QruclNW{Bv  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ?^gq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), >!3r7LgK  
nStartPos,nEndPos,i); ;)23@6{R%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); l>*L Am5  
fileSplitterFetch.start(); ^R h`XE  
} =Q~@dP  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SQ la]%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); XP^[,)E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,!vI@>nhG  
nEndPos = " + nFileLength); ddzMwucjp  
// fileSplitterFetch[nPos.length-1].start(); #5yz~&  
HAmAmEc,  
FjV)QP H  
//等待子线程结束 V/Q/Ujgg  
//int count = 0; ((AIrE>Rr  
//是否结束while循环 BF/l#)$yK  
boolean breakWhile = false; w`_"R6  
0q o]nw  
LhCwZ1  
while(!bStop) a)QSq<2*  
{ U(:Di]>{  
write_nPos(); p+#]Jr  
Utility.sleep(500); jK\AVjn  
breakWhile = true; $&X-ay o  
Cg3 d  
Mhu|S)hn  
for(int i=0;i<nStartPos.length;i++) #+8G`  
{ Sb.%B^O  
if(!fileSplitterFetch.bDownOver) vLIaTr gz  
{ &3f^]n!@  
breakWhile = false; VQ8Q=!]  
break; <.=-9O6  
} \49s;\I]  
} MW|R)gt  
if(breakWhile) Ya;y@44  
break; lf\x`3Vd  
^@f.~4P*I  
'x<o{Hi"\B  
//count++; l#TE$d^ym  
//if(count>4) nL+y"O  
// siteStop(); +!mEP>  
} t"?)x&dS  
D"CU J?  
RMHJI6?LB  
System.err.println("文件下载结束!"); m4?a'z"  
} LZDJ\"a-  
catch(Exception e){e.printStackTrace ();} Y=D\  
} L&0aS:  
3.6Gh|7  
rV}&G!V_t  
//获得文件长度 uyvjo)T  
public long getFileSize() Lk.tEuj=82  
{ 9V|) 3GF  
int nFileLength = -1; ZF@$3   
try{ [l}H%S   
URL url = new URL(siteInfoBean.getSSiteURL()); 40G'3HOp  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S0`u!l89(  
httpConnection.setRequestProperty("User-Agent","NetFox"); VIg6'  
|nBs(>b  
U|Uc|6  
int responseCode=httpConnection.getResponseCode(); \_x~lRqJJ  
if(responseCode>=400)  54#P  
{  'Pxq>Os  
processErrorCode(responseCode); CU:HTz=  
return -2; //-2 represent access is error \ 027>~u {  
} JCci*F#r  
MzH'<`;BP  
?JBA`,-  
String sHeader; M(vX.kF  
W;?e@}  
PMT}fg  
for(int i=1;;i++) 9"zp>VR  
{ $b)t`r+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (4|R}jv  
//Utility.log(in.readLine()); n`V?n  
sHeader=httpConnection.getHeaderFieldKey(i); qRHT~ta-?  
if(sHeader!=null) 2I283%xr  
{ mpQu:i|W  
if(sHeader.equals("Content-Length")) Lngf,Of.e  
{ dDa&:L  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); QH_Ds,oH=  
break; v#?;PyeF  
}  dZX;k0  
} u4$R ZTC  
else fZcA{$Vc]N  
break; }WhRJr`a  
} 5fRrd;  
} B$qTH5)W  
catch(IOException e){e.printStackTrace ();} 5?[hr5E.E  
catch(Exception e){e.printStackTrace ();} Q%524%f$  
q]U!n  
]D4lZK>H  
Utility.log(nFileLength); @^/aS;B$>  
^7yaM B!  
hkdF  
return nFileLength; FY`t7_Y?GV  
} $%4<q0-  
Cbp zYv32  
Qq'e#nI@  
//保存下载信息(文件指针位置) zB/VS_^^W:  
private void write_nPos() o]]sm}3N  
{ ) O&zb_{n  
try{ q[ 9N4nj$<  
output = new DataOutputStream(new FileOutputStream(tmpFile)); r&IDTS#  
output.writeInt(nStartPos.length); AD+OQLG]`  
for(int i=0;i<nStartPos.length;i++) &TL"Hd  
{ J *38GX+  
// output.writeLong(nPos); \(--$9  
output.writeLong(fileSplitterFetch.nStartPos); /pV N1Yt  
output.writeLong(fileSplitterFetch.nEndPos); 3D^cPkX  
} qHT73_R  
output.close(); }=Xlac_U  
} gAVD-]`  
catch(IOException e){e.printStackTrace ();} !c dY`f6x  
catch(Exception e){e.printStackTrace ();} I9m9`4BK  
}  e<(6x[_  
o1"N{ Eu  
%hlgLM  
//读取保存的下载信息(文件指针位置) sVGQSJJ5  
private void read_nPos() yFS{8yrRUU  
{ }Q@~_3,UJ  
try{ "n)AlAV@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1;'-$K`}  
int nCount = input.readInt(); }h1eB~6M  
nStartPos = new long[nCount]; R.DUfU"gp  
nEndPos = new long[nCount]; \98N8p;,I  
for(int i=0;i<nStartPos.length;i++) *?$M=tH  
{ n`@dk_%yI  
nStartPos = input.readLong(); &SNH1b#>E  
nEndPos = input.readLong(); ' sNiJ>  
} W;l0GxOxQ  
input.close(); L62%s[  
}  D[}^G5  
catch(IOException e){e.printStackTrace ();} t&NpC;>v  
catch(Exception e){e.printStackTrace ();} RWX!d54&  
} :H&G}T(#  
a>rDJw:  
&W c$VDC  
private void processErrorCode(int nErrorCode) Go^TTL   
{ >< >%;HZ  
System.err.println("Error Code : " + nErrorCode); hgzNEx%^q  
} qozvNJm)  
[S8*b^t4  
MT:VQ>f C  
//停止文件下载  UO#`Ak  
public void siteStop() QleVW  
{ z@w}+fYO  
bStop = true; JZ~wacDd  
for(int i=0;i<nStartPos.length;i++) %n GjP^  
fileSplitterFetch.splitterStop(); 4Gh\T`=  
<=D  a  
~MXhp5PI   
} bo(w$& VW  
} BFg&@7.X  
//负责部分文件的抓取 3Pgokj   
**FileSplitterFetch.java #HW<@E  
*/ vU5}E\Ny  
package NetFox; VIN0kRQ#  
RgW#z-PZF  
mwyB~,[d+W  
import java.io.*; A_WaRYG  
import java.net.*; F3]VSI6^E,  
Lq1?Y  
K#AexA  
public class FileSplitterFetch extends Thread { &:IcwD&  
E/*&'Osq  
cIG7 Q"4  
String sURL; //File URL "a}fwg9Y  
long nStartPos; //File Snippet Start Position mF|KjX~s  
long nEndPos; //File Snippet End Position )7[#Ti  
int nThreadID; //Thread's ID u"m(a:jQ  
boolean bDownOver = false; //Downing is over ^Il*`&+?P  
boolean bStop = false; //Stop identical `C C=?E  
FileAccessI fileAccessI = null; //File Access interface &6 <a<S  
h_+  
PB7-`uz  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException j;7E+Yp  
{ D6l. x]K  
this.sURL = sURL; 9jX_Eoxy  
this.nStartPos = nStart; >KvK'Mus/  
this.nEndPos = nEnd; ^Y+Lf]zz*  
nThreadID = id; GN9kCyPK  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 a@ <-L  
} %+Y wzL{  
?@;)2B|q  
s,8zj<dUv  
public void run() >`SeX:  
{ 02trjp.f  
while(nStartPos < nEndPos && !bStop) B>m*!n: l  
{ 9xhc:@B1J  
V>,=%r4f  
'P" i9j  
try{ )7.DF|A  
URL url = new URL(sURL); &e;Qabwxva  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); c-}[v<o  
httpConnection.setRequestProperty("User-Agent","NetFox"); % @+j@i`&  
String sProperty = "bytes="+nStartPos+"-"; QIevps*  
httpConnection.setRequestProperty("RANGE",sProperty); 'L-DMNxBr  
Utility.log(sProperty); M@<9/xPS  
f,Dic%$q  
 X(X[v]  
InputStream input = httpConnection.getInputStream(); ,Kl?-W@  
//logResponseHead(httpConnection); X-kOp9/.  
*o4a<.hd2  
Rz|@BxB>n  
byte[] b = new byte[1024]; gGUKB2)  
int nRead; g#^MO]pY  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !khEep}  
{ s</qT6@  
nStartPos += fileAccessI.write(b,0,nRead); 6 h,!;`8O  
//if(nThreadID == 1) M<n'ZDK `W  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {srxc4R`  
} `&7tADFB  
D9A%8o  
jVQ89vf ~  
Utility.log("Thread " + nThreadID + " is over!"); RR ^7/-  
bDownOver = true; DyiJ4m}kh  
//nPos = fileAccessI.write (b,0,nRead); X!^|Tass  
} 9J?s:"j  
catch(Exception e){e.printStackTrace ();} -~lq <M  
} xk% 62W  
} {vCtp   
1^X)vck  
O0xqA\  
//打印回应的头信息 y32$b,%Xi,  
public void logResponseHead(HttpURLConnection con) 3]*1%=~X/  
{ I 4?oBq  
for(int i=1;;i++) /\h*v!:  
{ ?_^{9q%9  
String header=con.getHeaderFieldKey(i); Q N#bd~  
if(header!=null) _UP fqC ?  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o!K DeY  
Utility.log(header+" : "+con.getHeaderField(header)); dCTyfXou[=  
else OQB7C0+ &  
break; HNv~ZAzBG-  
} [K\b"^=<  
} 2wIJ;rh  
!e~[U-  
C` ky=  
public void splitterStop() >20dK  
{ `(0B09~7  
bStop = true; PBCGC^0{  
} ix4]^  
SnQT1U%  
ybE 2N  
} YnU)f@b#  
pC>h"Hy  
CCe>*tdf  
/* |&rCXfC  
**FileAccess.java BB(6[V"SV  
*//文件访问(定位,写) LrbD%2U$j5  
package NetFox; A8Q^y AP^  
import java.io.*; {#k[-\|;  
CL4N/[UM  
7\,9Gcv1  
public class FileAccessI implements Serializable{ bC1G5`v_D  
!LwHKCj  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ~Q]5g7k=&  
RandomAccessFile oSavedFile; ,Q7;(&x~  
long nPos; )B0%"0?`8  
>!xyA;  
/0XMQy  
public FileAccessI() throws IOException mA+:)?e5~  
{ ()l3X.t,$  
this("",0); ~BmA!BZV`  
} ji1vLu4|t  
{XmCG%%L  
C\GP}:[T3  
public FileAccessI(String sName,long nPos) throws IOException &~Hed_  
{ znwKwc8,  
oSavedFile = new RandomAccessFile(sName,"rw"); Nb`qM]&  
this.nPos = nPos; (;},~( 2B  
oSavedFile.seek(nPos); IUFc_uL@\  
} @nY]S\if  
F9u?+y-xb  
5MAfuHq^  
public synchronized int write(byte[] b,int nStart,int nLen) ^F+7<$ 2  
{ TjEXR$:<  
int n = -1; =#S.t:HQ*  
try{ JN|6+.GG  
oSavedFile.write(b,nStart,nLen); kY~4AH  
n = nLen; j/*1zu8Y  
} *b. >  
catch(IOException e) nJ2x;';lA  
{ PU/<7P*  
e.printStackTrace (); 96(Mu% l  
} 6^ [ 4.D  
L!If~6oD(  
njaMI8|Pa  
return n; ujX; wGje  
} k_=yb^6[U  
Ptv'.<-  
T+F]hv'  
} 0\ = du  
TB! I  
-$Hu $Y}>  
/* wgS,U }/i  
**SiteInfoBean.java F#sm^%_2  
*/ dWvVK("Wj  
package NetFox; RDp  
(O5Yd 6u  
*{DTxEy  
public class SiteInfoBean { ZP<<cyY  
.+/d08]  
d}[cX9U/  
private String sSiteURL; //Site's URL ro{!X,_$,  
private String sFilePath; //Saved File's Path +1!iwmch>  
private String sFileName; //Saved File's Name Kf[d@ L  
private int nSplitter; //Count of Splited Downloading File rR> X<  
 S=(O6+U  
o[Jzx2A<  
public SiteInfoBean() (?na|yd  
{//nSplitter的缺省值为5 }|kFHodo  
//default value of nSplitter is 5 k||t<&`Ze  
this("","","",5); S' j g#*$  
} T$xB H  
;/j2(O^  
>CqzC8JF  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) E[]5Od5#  
{ No'?8+i  
sSiteURL= sURL; ecghY=%  
sFilePath = sPath; vA1Yya B  
sFileName = sName; E+]9!fDy<  
this.nSplitter = nSpiltter; N>!:bF  
_qxI9Q}<"  
) CP  
} cQU;PH]  
-Z"4W  
N]A# ecm  
public String getSSiteURL() "La;$7ds  
{ r!mRUw'u  
return sSiteURL; ?l0Qi  
} li r=0oq<  
T }}2J/sj  
'+PKGmRW  
public void setSSiteURL(String value) `<C<[JP:o  
{ 9{toPED  
sSiteURL = value; 6Yj{% G  
} lM6pYYEq=  
Gmz^vpQ]t  
0@ Y#P|QF  
public String getSFilePath() AG N/kx  
{ i+*!" /De  
return sFilePath; P=QxfX0B  
} 'r?ULft1  
~zqb{o^pT  
/,Xl8<~#  
public void setSFilePath(String value) Hc)z:x;Sj  
{ {{?g%mQ6  
sFilePath = value; Xu]~vik  
} HC%Hbc~S_Q  
.A2$C|a*  
=&WIa#!=  
public String getSFileName() 'a ['lF  
{ 8D='N`cN+  
return sFileName; Jj"{C]  
} {>f"&I<xw  
1@F-t94I  
ZEP?~zV\A  
public void setSFileName(String value) HL38iXQ( 3  
{ h: ' |)O  
sFileName = value; #Iw(+%D  
} g4IF~\QRVi  
lB,1dw2(T  
w&p+mJL.  
public int getNSplitter() 3 jZMXEG)  
{ 4b8G 1fm  
return nSplitter; C0wtMD:G  
} ~]?:v,UIm(  
 Aqy w  
1)ue-(o5  
public void setNSplitter(int nCount) v ,8;: sD  
{ <RGH+4LF  
nSplitter = nCount; sTM;l,  
} T6U/}&{O  
} S /hx\TzC  
;M:AcQZ|_  
`2mddx8  
/* X0lPRk53(  
**Utility.java p['RV  
*/ U'fP  
package NetFox; s^h@b!'7  
ar 3L|MN  
"rv~I_zl  
public class Utility { aZOn01v;!&  
Pq;OShU_  
7o E0;'  
public Utility() 2}hJe+#v  
{ A3jxjQ  
 G 3Z"U  
D)d]o&  
} sg2;"E@  
i}-uK,^  
//线程睡眠 AI|vL4*Xd  
public static void sleep(int nSecond) @(t3<g  
{ =+zDE0Qs  
try{ smP4KC"I(d  
Thread.sleep(nSecond); *_(X$qfoW  
} Nu5|tf9%A  
catch(Exception e) iQ'*QbP'Z  
{ pRd.KY -<  
e.printStackTrace (); yPN'@{ 5#  
} I652Fcj  
}  :Sq] |)  
)GD7 rsC`<  
//日志 &d_^k.%y  
public static void log(String sMsg)  WR;1  
{ HK;NR.D  
System.err.println(sMsg); LP2~UVq  
} [h/T IGE\  
 ;Shu  
lA^1}  
public static void log(int sMsg) _D '(R  
{ [&)]-2w2  
System.err.println(sMsg); J<$@X JLS  
} ARH~dN*C  
} /0s1;?  
osW"wh_  
>B BV/C'9  
/* kK6O ZhLH  
**TestMethod.java g`XngRb|j  
*/ W }N UU  
package NetFox; {{G)Ry*pb  
H>~CL  
7sot?gF  
public class TestMethod { jLAEHEs  
z0z@LA4k6@  
Qb536RpcTY  
public TestMethod() E&M(QX5  
{ ///xx/weblogic60b2_win.exe -+R,="nRQ  
try{ vObZ|>.J~O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); UP~28%>X  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `m,4#P-kj  
SiteFileFetch fileFetch = new SiteFileFetch(bean); (MwRe?Ih  
fileFetch.start(); ,}oAc  
} &f*o rM:  
catch(Exception e){e.printStackTrace ();} b^o4Q[  
b8mH.g&l  
PDNl]?  
} VYk:c`E  
J9^NHU  
]Q^)9uE\D  
public static void main(String[] args) Cf% qap#  
{ YT\`R  
new TestMethod(); ;%e&6  
} T{{:p\<]_  
} I/E9:  
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