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http断点续传简单实现(java)

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/* Hn>B!Bm*  
**SiteFileFetch.java @_:]J1jw7  
*/ Uw,2}yR  
package NetFox; ;z M*bWh9  
import java.io.*; r<F hY  
import java.net.*; R8rfM?"W  
{~|OE -X][  
Ev7J+TmXM  
public class SiteFileFetch extends Thread { mWR4|1(  
o9xlu.QL{c  
2aJS{[  
SiteInfoBean siteInfoBean = null; //文件信息Bean Le<w R  
long[] nStartPos; //开始位置 :1t~[-h^  
long[] nEndPos; //结束位置 3d<HN6&U  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ZxV"(\$n  
long nFileLength; //文件长度 .s+aZwTMT  
boolean bFirst = true; //是否第一次取文件 |#1(Z-}  
boolean bStop = false; //停止标志 pwwH<0[  
File tmpFile; //文件下载的临时信息 Y6,Rj:8  
DataOutputStream output; //输出到文件的输出流 1+-_s  
FOq1>>a0  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) c wg !j!l  
public SiteFileFetch(SiteInfoBean bean) throws IOException 9j W2  
{ ,rJXy_  
siteInfoBean = bean; !T](Udf  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [,2|Flf e  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {hln?'  
if(tmpFile.exists ()) AU-n&uX  
{ "qc6=:y}  
bFirst = false; d*)CT?d&  
read_nPos(); nhIa175'  
} 7j nIv];i  
else %dQxJMwj  
{ ,g%&|FAP  
nStartPos = new long[bean.getNSplitter()]; 5~mh'<:  
nEndPos = new long[bean.getNSplitter()]; 8NaqZ+5x  
} ,`ZYvF^%  
+)2s-A f-  
^Y-]*8;]  
T \w?$ s  
} kP/M< X"  
v1a6?-  
gX0R)spg  
public void run() \(t@1]&jw  
{ u7?$b!hG^C  
//获得文件长度 CR6R?R3b  
//分割文件 P!"&%d  
//实例FileSplitterFetch 6mKjau{r_  
//启动FileSplitterFetch线程 5@^ dgq  
//等待子线程返回 bdGIF'p%  
try{ \P1S|ufv  
if(bFirst) K&8dA0i2u2  
{ k)TSR5A  
nFileLength = getFileSize(); kcb.Wz~=  
if(nFileLength == -1) JyR/1 W  
{ }Tf9S<xpq3  
System.err.println("File Length is not known!"); p~*UpU8u  
} 71vkyn@"  
else if(nFileLength == -2) JH:0 L  
{ !S&L*OH,  
System.err.println("File is not access!"); V+I|1{@i0  
} t |~YEQ  
else o.q/O)'V u  
{ Qt vYv!  
for(int i=0;i<nStartPos.length;i++) $95h2oXt  
{ UI>Y0O  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 3e(ehLc4DJ  
} P(t[ eXe  
for(int i=0;i<nEndPos.length-1;i++) w`q%#q Rk  
{ ew"v{=X  
nEndPos = nStartPos[i+1]; =0;^(/1Mc  
} F<!)4>2@  
nEndPos[nEndPos.length-1] = nFileLength; /4xki_}  
} 'uq#ai[5I  
} 4.IU!.Uo  
L[=a/|)TBV  
5Hcf;P7   
//启动子线程 Q>n|^y6  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; MNSbtT*^  
for(int i=0;i<nStartPos.length;i++) (PfqRk1Y  
{ >3c@x  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), msVO H%wH  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), LVJxn2x6  
nStartPos,nEndPos,i); sJ]taY ou  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;A#`]-i C  
fileSplitterFetch.start(); [,TkFbDq"J  
} JwJ7=P=c  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }d<}FJ-,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ve\X3"p#  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", lkBdl#]9  
nEndPos = " + nFileLength); V{<xf f  
// fileSplitterFetch[nPos.length-1].start(); `X3^fg  
1x[)/@.'f  
=+AS/Jq  
//等待子线程结束 :UQTEdc{  
//int count = 0; RIIitgV_  
//是否结束while循环 nxr!`^Mne  
boolean breakWhile = false; ATR!7i\|  
+wkjS r`e  
YfRkwKjy(  
while(!bStop) /{|fyKo\?  
{ P3oI2\)*i  
write_nPos(); R+Y4|  
Utility.sleep(500); %rxO_  
breakWhile = true; H/Llj.-jg  
g&`pgmUX  
fJ ,1Ef;Z  
for(int i=0;i<nStartPos.length;i++) ",!1m7[wF  
{ :sC qjz  
if(!fileSplitterFetch.bDownOver) Fy.\7CL>  
{ 9~l hsH  
breakWhile = false; _U/!4A  
break; HeG)/W?r  
} KCWc`Oz  
} {#{DH?=^)u  
if(breakWhile) B9wPU1  
break; 8cA~R-  
aXL{TD:]  
{RF-sqce  
//count++; &B|D;|7H  
//if(count>4) Q9Q|lO  
// siteStop(); $]8h $  
} *cEob b  
DZ_lW  
nB!&Zq  
System.err.println("文件下载结束!"); $#]]K  
} rta:f800z  
catch(Exception e){e.printStackTrace ();} -N"&/)  
} 0@EwM  
qM.bF&&Go  
4T=u`3pD7l  
//获得文件长度 kV3 8`s>+  
public long getFileSize() ~j<+k4I~  
{ 3"P }n  
int nFileLength = -1; 5sb\r,kW  
try{ 1 CHeufQ  
URL url = new URL(siteInfoBean.getSSiteURL()); Ry|!pV  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8KRba4[  
httpConnection.setRequestProperty("User-Agent","NetFox"); 6qp%$>$Vt;  
[/X4"D-uOK  
ldp%{"ZZ  
int responseCode=httpConnection.getResponseCode(); Hbpqyl%O>  
if(responseCode>=400) /"B?1?qc,=  
{ DoeiW=  
processErrorCode(responseCode); 0fYj4`4=n  
return -2; //-2 represent access is error W>O~-2  
} CjiVnWSz<  
d$ ^ ,bL2p  
?`4+cx}n  
String sHeader; zSFDUZ]A3  
phgm0D7  
a AB`G3  
for(int i=1;;i++) A7n\h-b  
{ CXC`sPY  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); f{FDuIl n  
//Utility.log(in.readLine()); 8)4P Ll  
sHeader=httpConnection.getHeaderFieldKey(i); o";Z$tAJkC  
if(sHeader!=null) &0`) Q  
{ {>F7CT'G6  
if(sHeader.equals("Content-Length")) %%4t~XC#  
{ %wSj%>&-R  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *Q,0W:~-  
break; z-b*D}&  
} u07pq4Ly  
} WoBo9aR  
else =X.9,$Y  
break; nI*v820,  
} rW0FA  
} /jRRf"B  
catch(IOException e){e.printStackTrace ();} qu-/"w<3$  
catch(Exception e){e.printStackTrace ();} $bsG]  
B|&"#Q  
EcCFbqS4W  
Utility.log(nFileLength); 9F*+YG!  
ETXZ?\<a5  
!Uq^7Mw  
return nFileLength; @0SC"CqM  
} TEaJG9RU>v  
uNHF'?X  
+*hm-lv?  
//保存下载信息(文件指针位置) :Cp'm'omb  
private void write_nPos() /=gOa\k|p  
{ 4Z/Q=Mq2  
try{ Iwc{R8BV  
output = new DataOutputStream(new FileOutputStream(tmpFile)); GPGm]Gt  
output.writeInt(nStartPos.length); 4A2?Uhp y  
for(int i=0;i<nStartPos.length;i++) 0eS)&GdR  
{ n2fbp\I  
// output.writeLong(nPos); <Ce2r"U1e  
output.writeLong(fileSplitterFetch.nStartPos); $]A/ o(  
output.writeLong(fileSplitterFetch.nEndPos); uECsh2Uin  
} Gqy,u3lE  
output.close(); $n^gmhp  
} NvvUSyk\;s  
catch(IOException e){e.printStackTrace ();} ;asP4R=  
catch(Exception e){e.printStackTrace ();} Q J7L7S  
} l!g]a2x*  
/)>s##p*  
kVy\b E0o  
//读取保存的下载信息(文件指针位置) a@0BBihz  
private void read_nPos() 6%VV,$p  
{ gw}Mw  
try{ ~mR'Q-hi<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); >z.<u|r2  
int nCount = input.readInt(); ?|ZTaX6A  
nStartPos = new long[nCount]; ti<;7Yb  
nEndPos = new long[nCount]; 4M^G`WA}t9  
for(int i=0;i<nStartPos.length;i++) D7S'*;F  
{ `8Lo{P  
nStartPos = input.readLong(); Z%n(O(^L  
nEndPos = input.readLong(); ZE/o?4k*c1  
} FTeu~<KpM  
input.close(); $O*O/ iG  
} Z%x\~ )~  
catch(IOException e){e.printStackTrace ();} T N!=@Gy  
catch(Exception e){e.printStackTrace ();} ^*fxR]Y  
} lf!FTm7  
/0eYMG+K=  
rQaxr!  
private void processErrorCode(int nErrorCode) W[}s o6  
{  &CG*)bE  
System.err.println("Error Code : " + nErrorCode); HuV J\%.  
} R%c SJ8O#  
XB_B4X1R  
Jzp#bgq}|  
//停止文件下载 Nq@+'<@p$  
public void siteStop() HX6Ma{vBk  
{ &|`C)6[C  
bStop = true; kGN+rHo   
for(int i=0;i<nStartPos.length;i++) "&%#!2  
fileSplitterFetch.splitterStop(); E]6z8juO6  
'gt-s547  
I'@Ydt2  
} Q(\4]i< S  
} IEcf  
//负责部分文件的抓取 kWrp1`  
**FileSplitterFetch.java e~"fn*"  
*/ $]q8, N|1  
package NetFox; Bk+{RN(w  
<$hu   
(k|_J42[  
import java.io.*; is@b&V]  
import java.net.*; M_%B|S {  
fks)+L'  
bN3#{l-`  
public class FileSplitterFetch extends Thread { bl'z<S, '  
<~)kwq'  
jH6&q~#  
String sURL; //File URL J;prC  
long nStartPos; //File Snippet Start Position @ G4X  
long nEndPos; //File Snippet End Position +Lnsr\BA  
int nThreadID; //Thread's ID ku..aG`  
boolean bDownOver = false; //Downing is over hnznp1[#@  
boolean bStop = false; //Stop identical wGZR31  
FileAccessI fileAccessI = null; //File Access interface \{EpduwZ  
"hy.GWF|*  
0pSmj2/,.  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @GvztVYo  
{ Z*FrB58  
this.sURL = sURL; K_ ci_g":  
this.nStartPos = nStart; T =2=k&|  
this.nEndPos = nEnd; Vy|6E#U  
nThreadID = id; oaK%Ww6~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 t>uN'oCyC  
} a<h1\ `H7  
7YAIA%8  
y7|P-3[ 4w  
public void run() 0{j&6I2  
{ "t0kAG  
while(nStartPos < nEndPos && !bStop) k}#;Uy=5  
{ 8Y#\xzod  
DU=dLE6-P;  
Tc+gdo>G  
try{ 0Ld@H)  
URL url = new URL(sURL);  <Tot|R;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); G\a8B#hg  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,<Q~b%(3  
String sProperty = "bytes="+nStartPos+"-"; W'on$mB5<  
httpConnection.setRequestProperty("RANGE",sProperty); -D^}S"'  
Utility.log(sProperty); Kb^>-[Yx  
>[1W:KQA  
2>l,no39t+  
InputStream input = httpConnection.getInputStream(); ZoB {x*IH  
//logResponseHead(httpConnection); nA~E "*  
U bYEEY#  
g(| 6~}|o+  
byte[] b = new byte[1024]; /CIh2 ]#e  
int nRead; XhPe]P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) g%k`  
{ P(a.iu5   
nStartPos += fileAccessI.write(b,0,nRead); w\19[U3  
//if(nThreadID == 1) g5q$A9.Jl  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); U-^[lWn[@4  
} tM#lFmdd\P  
@;?T~^nGj  
_0 m\[t.  
Utility.log("Thread " + nThreadID + " is over!"); PG]%Bv57  
bDownOver = true; Gx 72  
//nPos = fileAccessI.write (b,0,nRead); WW@d:R  
} rP(eva  
catch(Exception e){e.printStackTrace ();} !(t,FYeH  
} ]1gx#y 2  
} YKa0H%B(  
kHv[H]+v  
<s@-:;9~  
//打印回应的头信息 U/NBFc:[y:  
public void logResponseHead(HttpURLConnection con) JO'>oFv_W  
{ c )7j QA  
for(int i=1;;i++) :h1pBEiH  
{ zW8*EE+,  
String header=con.getHeaderFieldKey(i); T{}fHfM  
if(header!=null) &''WRgZ}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); K]xa/G(  
Utility.log(header+" : "+con.getHeaderField(header)); Cb:gH}j  
else WGAXIQ  
break; !7d*v3)d  
} %5*@l vy  
} U'*t~x <  
5IKL#V `3a  
5#E |R  
public void splitterStop() wJlX4cT4YV  
{ pN&c(=If  
bStop = true; m~'? /!!  
} D.%B$Y;G  
Y[SU&LM  
|/ }\6L]  
} y3<Y?M4  
1h7+@#<:a  
]/cd;u  
/* vOgC>_x7  
**FileAccess.java *x>3xQq&  
*//文件访问(定位,写) j( #%tIv  
package NetFox; z* <y5  
import java.io.*; 0ji q-3V)  
*{o UWt  
=?X$Yaw*  
public class FileAccessI implements Serializable{ T$= 4O9G  
Q7bq  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pA4*bO+  
RandomAccessFile oSavedFile; ]h9!ei [  
long nPos; QjPj[c  
$t-n'Qh^2  
jtm?z c  
public FileAccessI() throws IOException ]8;n{ }X  
{ #;# 3%?  
this("",0); },[;O^Do^{  
} Pj?Dmk~   
 st 'D  
gf)t)-E  
public FileAccessI(String sName,long nPos) throws IOException j 6ut}Uq  
{ B%\gkl  
oSavedFile = new RandomAccessFile(sName,"rw"); 5HS~op2n/  
this.nPos = nPos; q*)+K9LRk  
oSavedFile.seek(nPos); rbqo"g`  
} ,LOQDIyn  
N]YtLa,t  
Jg$xO@.  
public synchronized int write(byte[] b,int nStart,int nLen) kVS?RHR  
{ Ov82ibp_1  
int n = -1; #2xSyOrmf  
try{ Rb}KZ+o "Z  
oSavedFile.write(b,nStart,nLen); <a le$[  
n = nLen; gBk5wk_j|  
} H g5++.Bp  
catch(IOException e) =22ALlxk  
{ A 699FQ  
e.printStackTrace (); B8I4[@m>w\  
} SNT5Amz!  
zX7q:Pt  
)$x_!=@1  
return n; $(q>mg:H  
} N6Z{BLZ  
]|:uU  
vs&8wbS)  
} _U)%kY8  
i z]rFNR  
rSV gWr8  
/* !Ngw\@f  
**SiteInfoBean.java KbxR Lx]w  
*/ xU9@$am  
package NetFox; `&$B3)Eb  
R UTnc  
qI3NkVA'C  
public class SiteInfoBean { G6`J1Uk  
V7t!?xOL  
gd6Dm4q(  
private String sSiteURL; //Site's URL +1;'B4  
private String sFilePath; //Saved File's Path \.s`n2.w  
private String sFileName; //Saved File's Name hh.Q\qhubB  
private int nSplitter; //Count of Splited Downloading File #-cTc&$O;  
*9gD*AnM,  
gY9\o#)<  
public SiteInfoBean() sY;lt.b  
{//nSplitter的缺省值为5 J7i+c];!<  
//default value of nSplitter is 5 D>wZ0p b-  
this("","","",5); R21~Q:b !  
} u@.>WHQN  
VS/;aG$&y  
PK rek  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) $R^lo $(  
{ #2%([w  
sSiteURL= sURL; M2T|"Q"=  
sFilePath = sPath; [B6DC`M  
sFileName = sName; qs=tJ ^<<o  
this.nSplitter = nSpiltter; d$;/T('  
s\0Ko1  
@%W]".*'}  
} Yr&Ka:  
@C.GKeM*  
Nw](".  
public String getSSiteURL() C9KWa*3  
{ S_8r\B[>P  
return sSiteURL; &/ ouW'oP  
} !E& MBAKy  
=l`OHTg  
?~2Bi^W5  
public void setSSiteURL(String value) !0fI"3P@r  
{ x,Y 5U+]E  
sSiteURL = value; |pWaBh|r  
} # .q#O C  
u.6P-yh  
u3ds QU  
public String getSFilePath() .2X2b<%)  
{ vD=%`G[m  
return sFilePath; ]h~o],:  
} D[>W{g $  
^9ng)  
2@MN]Low  
public void setSFilePath(String value) Jgi Iq  
{ (@ ]tG?I=  
sFilePath = value; H=. K  
} Hq xK\m%,.  
 *W^=XbG  
8B@J Fpg^  
public String getSFileName() \f"?Tv-C'  
{ N8+P  
return sFileName; ,k*F`.[  
} 4MX7=!E  
x N`T  
$A?}a  
public void setSFileName(String value) En5!"w|j  
{ KU2$5[~j  
sFileName = value; fI11dE9&?[  
} $!`L"szqD*  
5G? .T?  
W/v|8-gcK  
public int getNSplitter() `s}BXKIv}  
{ "T*I|  
return nSplitter; F!~l MpuE  
} $^Ca: duk  
/2h][zrZ[.  
G?[-cNdk  
public void setNSplitter(int nCount) ]p$zvMf}  
{ !0dX@V'r  
nSplitter = nCount; @)z*BmP  
} ;E's4jWq  
} _0]QS4a][c  
uL>:tb  
eycV@|6u*  
/* jYdV?B  
**Utility.java ;](h2Z`3s  
*/ .&(8(C  
package NetFox; 4e/cqN 6  
sV'v* 1|  
|#cAsf_{  
public class Utility { 9cOx@c+/  
E$T(Qu<-  
0 pNo`Bm  
public Utility() #HDesen  
{ !Mil?^  
_m7c o :  
{]M>Y%j48  
} .93S>U<_  
)l{A{f6O  
//线程睡眠 YOKR//|3  
public static void sleep(int nSecond) N ^f}ui i  
{ > Z++^YVE  
try{ .Qk{5=l6P  
Thread.sleep(nSecond); `]hCUaV   
} ZvyjMLf  
catch(Exception e) ;o%:7 &  
{ IQoH@l&Xk  
e.printStackTrace (); uWrFunh%  
} }s6G!v^2""  
} ;/aB)JZ5=  
O=`o'%K<  
//日志 iUCwKpb9  
public static void log(String sMsg) U IQ 6SvM  
{ K#;txzi  
System.err.println(sMsg); )"-fHW+fy  
} `uhL61cMp  
?.j,Bq5At  
2MT_#r_  
public static void log(int sMsg) *JS"(. '(  
{ i^/Di Wdyf  
System.err.println(sMsg); .h!9wGi`  
} r?afv.@L2  
} ^#7viZ*  
fOJj(0=y  
x cnt?%%M  
/* [>wzl"cHW  
**TestMethod.java Pzptr%{  
*/ W60Q3  
package NetFox; x{2o[dK4}  
iBS0rT_  
1>yha j(K  
public class TestMethod { taixBNv  
Z]p8IH%~92  
2| $k`I,  
public TestMethod() y\@SC\jk|  
{ ///xx/weblogic60b2_win.exe excrXx  
try{ :SQ LfOQ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); L-MiaKcL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Lv^a+'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); v2(U(Tt  
fileFetch.start(); fX""xT NPi  
} 9yDFHz w  
catch(Exception e){e.printStackTrace ();} p/4S$ j#Tn  
,?fN#gc :  
l&$*}yCK  
} H}(=?}+  
< )Alb\Z  
(Q\\Gw   
public static void main(String[] args) at=D&oy4"+  
{ ?U$}Rsk{#  
new TestMethod(); <gR`)YF7  
} 8 `o{b"l+  
} C*$|#.l  
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