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http断点续传简单实现(java)

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/* i(# Fjp  
**SiteFileFetch.java E.*wNah"U  
*/ V^ ;l g[:  
package NetFox; 'wBOnGi6  
import java.io.*; =b6G' O[  
import java.net.*; uE,T Ea9;  
^MhMYA  
B/~ubw  
public class SiteFileFetch extends Thread { Gh3f^PWnc  
$b_~  
U+ D#  
SiteInfoBean siteInfoBean = null; //文件信息Bean V+|$H h8  
long[] nStartPos; //开始位置 ]P^ 3uXi  
long[] nEndPos; //结束位置 9CIQRc  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Vd) %qw  
long nFileLength; //文件长度 cqb6]  
boolean bFirst = true; //是否第一次取文件 ^6CPC@B1  
boolean bStop = false; //停止标志 eq2L V=d{m  
File tmpFile; //文件下载的临时信息 ?^8.Sa{  
DataOutputStream output; //输出到文件的输出流 0+_;6  
{FC<vx{42  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) _39VL  
public SiteFileFetch(SiteInfoBean bean) throws IOException F Zt;D  
{ 7=wQ#bq"1P  
siteInfoBean = bean; #aP;a-Q|k  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Ym-mfWo^#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !;k ^  
if(tmpFile.exists ()) [[4!b E  
{ 3)^ 2X  
bFirst = false; zJ8jJFL+Y  
read_nPos(); S~g "  
} $qoal   
else Y\(?&7Aax  
{ puF*WxU)  
nStartPos = new long[bean.getNSplitter()]; #Oa`P  
nEndPos = new long[bean.getNSplitter()]; h9. Yux  
} q}"HxMJ  
r6:nYyF$)v  
$z@nT.x5  
m Le 70U  
} jlD3SF~2  
r)G)i;;~*  
m&_!*3BAG  
public void run() ]7|qhAh<L  
{ X5Y. o&  
//获得文件长度 b%j4W)Z  
//分割文件 _z"\3hZ  
//实例FileSplitterFetch Z= pvoTY  
//启动FileSplitterFetch线程 PB{5C*Y7^k  
//等待子线程返回 DxP65wU  
try{ $*9:a3>zny  
if(bFirst) /hGu42YG  
{ 1Zp^X:(  
nFileLength = getFileSize(); fAT M?  
if(nFileLength == -1) |'L$ogt6  
{ 'EU|w,GL}  
System.err.println("File Length is not known!"); 8PRB_ny  
} 5XNFu C9E  
else if(nFileLength == -2) DCCij N  
{ s*kSl:T @O  
System.err.println("File is not access!"); aQ1n1OBr  
} \AD|;tA\vE  
else (rf8"T!"  
{ <$ nMqUu0  
for(int i=0;i<nStartPos.length;i++) Wb{8WPS  
{ `~qVo4V6Z  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 1lv. @-  
} lIatM@gU  
for(int i=0;i<nEndPos.length-1;i++) "Z a}p|Ct  
{ 5PKdMEK|q  
nEndPos = nStartPos[i+1]; E{B40E~4  
} =XUt?5  
nEndPos[nEndPos.length-1] = nFileLength; myZ8LQ&  
} z-kB!~r  
} YtT:\#D  
rf2-owWN  
4?7OP t6  
//启动子线程 O~F8lQ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %e=UYBj"  
for(int i=0;i<nStartPos.length;i++)  Y}Nd2  
{ ?uE@C3 e  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1ZfhDtK(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), -s6;IoG/  
nStartPos,nEndPos,i); Snas:#B!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); g6q67m<h  
fileSplitterFetch.start();  ] 2lh J  
} @p7*JLO  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F[oTc^dr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0^ $6U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", F:2V;  
nEndPos = " + nFileLength); }?%5Ae7l,  
// fileSplitterFetch[nPos.length-1].start(); r1xhplHH@  
-;[,`g(f  
%R*-oQ1T  
//等待子线程结束 yLCJSN$7  
//int count = 0; &28%~&L  
//是否结束while循环 ^@xn3zJ  
boolean breakWhile = false;  f(*^zga,  
)}R w@70L-  
E`UEl$($  
while(!bStop) nOUF<DNQ  
{ !\1Pu|  
write_nPos(); k*= #XbX  
Utility.sleep(500); @RI\CqFHR  
breakWhile = true; ~YrO>H` B  
' sTMUPg`  
*8xMe  
for(int i=0;i<nStartPos.length;i++) 1"} u51  
{ 8|\?imOp\[  
if(!fileSplitterFetch.bDownOver) 5 ]@"f/  
{ H5p&dNO  
breakWhile = false; g=n /w  
break; A{QA0X!p  
} Q|:qs\6q5  
} s4{>7`N2  
if(breakWhile) Ba]^0Y u  
break; [5Pin>]z  
2t"&>1  
Z\*jt B:  
//count++; c o%-d  
//if(count>4) $<s 3;>t  
// siteStop(); %C(^v)"  
} [cf!%3>53  
I> z0)pB  
i6D66E  
System.err.println("文件下载结束!"); 5KDN8pJN  
} "\M^jO  
catch(Exception e){e.printStackTrace ();} K)r|oW=6Y  
} p v*n.U6  
$/;;}|hqi  
InR/g@n+D1  
//获得文件长度 d,caOE8N  
public long getFileSize() JQ]A"xTIa*  
{ 4z>SI\Ss  
int nFileLength = -1; 924a1  
try{ H{j jA+0  
URL url = new URL(siteInfoBean.getSSiteURL()); E?[]N[0Kl  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `%S#XJU  
httpConnection.setRequestProperty("User-Agent","NetFox"); %w3"B,k'9D  
Omy<Y@$  
"AUHe6Yv  
int responseCode=httpConnection.getResponseCode(); .=<<b|  
if(responseCode>=400) ?mJ&zf|B8  
{ 0Wc8\c  
processErrorCode(responseCode); !qF t:{-h  
return -2; //-2 represent access is error Z`Sbq{Kx  
} L4-v'Z;  
2io~pk>  
MF/@Efjn ]  
String sHeader; &i?>mt  
zsuXN*  
Ub-q0[6  
for(int i=1;;i++) $ z 5  
{ eJwHeG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }:a:E~5y  
//Utility.log(in.readLine()); 8[xl3=  
sHeader=httpConnection.getHeaderFieldKey(i); 8xN+LL'T{  
if(sHeader!=null) @Lf-=9  
{ g<$q#l~4xH  
if(sHeader.equals("Content-Length")) :J6lJ8w ?  
{ $c<NEt_\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); U[t/40W}P  
break; xb~8uD5  
} |Y&&g=7  
} yRv4,{B}X>  
else G2BB]] m3  
break; Kk9W=vd  
} s'Wu \r'  
} n!$zO{P  
catch(IOException e){e.printStackTrace ();} ];8S<KiS~  
catch(Exception e){e.printStackTrace ();} .DG`~Fpk  
_[t:Vme}v  
7@uhw">mX  
Utility.log(nFileLength); ?,0 a#lG  
*$yU|,  
cHjnuL0fsy  
return nFileLength; q aZQ1<e  
} p]erk  
$Cx?%X^b  
Gj H$!P=.  
//保存下载信息(文件指针位置) Js}1_K  
private void write_nPos() ni`uO<\U  
{ {ZIEIXWb2  
try{ R7ze~[oF  
output = new DataOutputStream(new FileOutputStream(tmpFile)); J_rb3  
output.writeInt(nStartPos.length); I$HO[Z!  
for(int i=0;i<nStartPos.length;i++) ^^Te  
{ @K=C`N_22  
// output.writeLong(nPos); >JckN4 v  
output.writeLong(fileSplitterFetch.nStartPos); {~cM 6W]f  
output.writeLong(fileSplitterFetch.nEndPos); :ExCGS[  
} zqt{oN_  
output.close(); Sahz*f  
} ptMDhMVW  
catch(IOException e){e.printStackTrace ();} e-Ma8+X\  
catch(Exception e){e.printStackTrace ();} qbD>)}:1  
} ykat0iqo  
oo2CF!Xy  
<<l1 zEf@  
//读取保存的下载信息(文件指针位置) YgL{*XYAt  
private void read_nPos() >PmnR>x-rj  
{ S";c7s  
try{ 7X`]}z4g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !THa?U;  
int nCount = input.readInt(); c%@< h6  
nStartPos = new long[nCount]; '4"c#kCKL  
nEndPos = new long[nCount]; S-%itrB*  
for(int i=0;i<nStartPos.length;i++) [2\jQv\Y  
{ v1}9i3Or#  
nStartPos = input.readLong(); ~6Pv5DKq  
nEndPos = input.readLong(); 8$`$24Wx  
} ^n~bx *f  
input.close(); 1'4?}0Dok  
} )/cf%  
catch(IOException e){e.printStackTrace ();} [D_s`'tg  
catch(Exception e){e.printStackTrace ();} h h7unHt-  
} (bp4ly^  
|e{ ^Yf4  
^aR^M\38  
private void processErrorCode(int nErrorCode) []b= xRJM  
{ T7R,6 qt  
System.err.println("Error Code : " + nErrorCode); r%\%tz'`j  
} eY\w ?pT2  
$q*hE&x Qd  
pPsT,i?  
//停止文件下载 I_\?wSNGM  
public void siteStop() ^2C \--=;  
{ yIYQ.-DkS+  
bStop = true; MnTJFo"  
for(int i=0;i<nStartPos.length;i++) !q!5D`  
fileSplitterFetch.splitterStop(); h,|. qfUk  
7A"v:e  
z9Nial`p  
} <%?!3 n*  
} G3dA`3  
//负责部分文件的抓取 4t,f$zk  
**FileSplitterFetch.java w:aV2  
*/ A9Icn>3?`(  
package NetFox; S\L^ZH?[2  
zS*vKyye>  
weC.k x   
import java.io.*; TpcJ1*t  
import java.net.*; i F \H  
Ruv`yfQ  
)~-r&Q5d  
public class FileSplitterFetch extends Thread { 7sq15oL  
z-N N( G+  
>!MRk[@ V-  
String sURL; //File URL QD^q\9U[  
long nStartPos; //File Snippet Start Position (;9j#x  
long nEndPos; //File Snippet End Position `*",_RO;  
int nThreadID; //Thread's ID >u+%H vzc  
boolean bDownOver = false; //Downing is over |eI!wgQx  
boolean bStop = false; //Stop identical p^k*[3$0  
FileAccessI fileAccessI = null; //File Access interface Zu /w[*;M  
)F+wk"`+6  
p|g7Z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException G@P+M1c  
{ m:6*4_!  
this.sURL = sURL; \+j:d9?  
this.nStartPos = nStart; ),J6:O&  
this.nEndPos = nEnd; +CN!3(r  
nThreadID = id; ~9Qd83`UH  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 M>d^.n  
} 4JRQ=T|P7I  
zZ94_8b  
08+\fT [  
public void run() 5,J.$Sax  
{ tMH 2  
while(nStartPos < nEndPos && !bStop) M|fC2[]v B  
{ B`)TRt+'.  
fd$nAE  
@MP;/o+  
try{ 9[R+m3V/`  
URL url = new URL(sURL); +GncQs y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p z\8Bp}yo  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q^*4FH!W  
String sProperty = "bytes="+nStartPos+"-"; Irui{%T  
httpConnection.setRequestProperty("RANGE",sProperty); <%.lPO]&E  
Utility.log(sProperty); t;V^OGflv  
L7[f-cK2:  
gx8i|]  
InputStream input = httpConnection.getInputStream(); Tvt(nWn(H1  
//logResponseHead(httpConnection); P9W?sPnC5  
t;`ULp~&  
5zOC zm  
byte[] b = new byte[1024]; mt~E&Z(A  
int nRead; Qb|@DMq%  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .bUj  
{ Mm;[f'{M)  
nStartPos += fileAccessI.write(b,0,nRead); 3&6sQ-}*  
//if(nThreadID == 1) \5}*;O@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); _2hZGC%&E  
} @z^7*#vQv  
U/-k'6=M  
KL./  
Utility.log("Thread " + nThreadID + " is over!"); gC(@]%  
bDownOver = true; 2 fg P  
//nPos = fileAccessI.write (b,0,nRead); 0BH-kr  
} (/FG#D.  
catch(Exception e){e.printStackTrace ();} ]=PkgOJD  
} h>F"GR?U_(  
} q4v:s   
5O;D\M{>  
l#~pK6@W  
//打印回应的头信息 M%WO  
public void logResponseHead(HttpURLConnection con) j2%fAs<  
{ @}2EEo#  
for(int i=1;;i++) 51tZ:-1!  
{ |{JI=$  
String header=con.getHeaderFieldKey(i); Shv$"x:W  
if(header!=null) OZA^L;#>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); V"B/4v>  
Utility.log(header+" : "+con.getHeaderField(header)); qeb}~FL"o  
else C-\3,  
break; xIwILY|W=  
} O`5hj q#  
} +cM~|  
h^ K]ASj  
[N#4H3GM8  
public void splitterStop() Km,%p@`m  
{ 6AoKuT;  
bStop = true; IJVzF1vC  
} [] el4.J,  
lF t^dl^  
?C- ju8]|  
} U1(cBY  
v!$:t<-5N  
mT #A?C2  
/* Z*ag{N  
**FileAccess.java W23Q>x&S  
*//文件访问(定位,写) Te`@{>  
package NetFox; TV#>x!5!d  
import java.io.*; T Y% =Y=  
B3pjli  
iXq*EZb"R  
public class FileAccessI implements Serializable{ *Q)-"]O(k  
" %qr*|  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 :K5?&kT  
RandomAccessFile oSavedFile; wWSo+40  
long nPos; 1xu~@v 60  
]s!id[j  
^!x! F  
public FileAccessI() throws IOException 8]oolA:^4s  
{ "0,FB4L[U5  
this("",0); '1(6@5tyWk  
} mHV{9J  
R:3=!zav  
IRueq @4  
public FileAccessI(String sName,long nPos) throws IOException Nukyvse  
{ V]GF53D  
oSavedFile = new RandomAccessFile(sName,"rw"); ^tjw }sE  
this.nPos = nPos; ! ,{zDMA  
oSavedFile.seek(nPos); S^;;\0#NK  
} ~$C}?y^ a  
9 )!}  
|28'<BL  
public synchronized int write(byte[] b,int nStart,int nLen) ,i Y:#E  
{ ;9~ WB X"  
int n = -1; pwkTe  
try{ ~)n[Vf  
oSavedFile.write(b,nStart,nLen); <*WGvCh%w  
n = nLen; 3fA+{Y8S  
} X6T[+]Gc  
catch(IOException e) TZ `Ypi7r  
{ 1up p E|  
e.printStackTrace (); i]J.WFu  
} _RbM'_y+E  
>{9VXSc  
!tcz_%  
return n; k5J18S  
} dpK -  
G.^)5!By  
QqRF?%7q"q  
} '2hy%  
2g~ @99`  
: p)R,('g  
/* ij! ],  
**SiteInfoBean.java D4C:%D  
*/ 7qZC+x6_L  
package NetFox; -FI)o`AE  
}2;iIw`  
<:NahxIlu  
public class SiteInfoBean { B-$?5Ft!  
%l14K_  
+2}cR66%  
private String sSiteURL; //Site's URL [ZC\8tP`V  
private String sFilePath; //Saved File's Path 93:oXyFjD  
private String sFileName; //Saved File's Name 97$Q?a8S@  
private int nSplitter; //Count of Splited Downloading File KO%$  
W$2 \GPJt  
2K{'F1"RM  
public SiteInfoBean() _x1W\#  
{//nSplitter的缺省值为5 ~, E }^  
//default value of nSplitter is 5 l U8pX$  
this("","","",5);  @;$cX2  
} :CK`v6 Qs  
S89j:KRXH%  
3 o$zT9j  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) +RJKJ:W  
{ WJu(,zM?G  
sSiteURL= sURL; 5S2 j5M00  
sFilePath = sPath; ]z5hTY  
sFileName = sName; rMHh!)^#W  
this.nSplitter = nSpiltter; 9(O eH7  
T/2k2r4PD  
]jC{o,?s  
} h#KSKKNW  
eY'n S  
4L ]4WVc  
public String getSSiteURL() `GW&*[.7  
{ iw=e"6V  
return sSiteURL; sNcU>qjj6  
} p JT)X8K"  
/]'&cD 1  
od5nRb  
public void setSSiteURL(String value) m;\nMdn  
{ jf`w8*R  
sSiteURL = value; =}kISh  
} mXyN{`q=  
4w=v /WDo  
z-b78A/8  
public String getSFilePath() 8a`3eM~?[  
{ RXg\A!5GV  
return sFilePath; |aAyWK  S  
} -j]c(Q MA]  
`B4Ilh"d  
~3M8"}X;L  
public void setSFilePath(String value) {6GX ?aw'  
{ 7M7Lj0Y)L  
sFilePath = value; 8/(}Wet  
} >l><d!hw  
wdfbl_`T  
iQ(j_i'+!I  
public String getSFileName() _pZ <  
{ 1.k=ji$D0  
return sFileName; |9\i+)C  
} k ,ldi  
G+Z ,i c  
s R>>l3H  
public void setSFileName(String value) f S/:OnH  
{ M>Tg$^lm  
sFileName = value; }2LWDQ;po  
} vs[!B-  
D (8Z90  
UkpTK8>&  
public int getNSplitter() *]NfT}}  
{ "_\"S  
return nSplitter; fdX|t "oz  
} ][tR=Y#&y5  
hU-FSdR  
`|>]P"9yp  
public void setNSplitter(int nCount) Hzm_o>^KC  
{ b@8z+,_  
nSplitter = nCount; cZ|NGkZ  
} ga/zt-&  
} z9 Ch %A{  
~cSXBc,+  
du$M  
/* ?%$O7_ThvA  
**Utility.java M1Ff ,]w  
*/ ,cS#  
package NetFox; &'&)E((  
aVK,( j9u  
mj e9i  
public class Utility { s|A[HQUtJ  
}q]*aADe  
}A@:JR+|  
public Utility() W)bSLD   
{ f3G:J<cL  
&U?4e'N)T  
Z8FgxR  
} <!FcQVH+L  
]s0wJD=  
//线程睡眠 zps =~|  
public static void sleep(int nSecond) SyI~iW#Y1  
{ Qt {){uE  
try{ iTq&h=(n  
Thread.sleep(nSecond); Y)F(-H)  
} Z81;Y=(  
catch(Exception e) SO *oBA'  
{ =TNFAt  
e.printStackTrace (); HM0&%  
} WwTl|wgvyI  
} M>m!\bb%.  
@@K/0:],  
//日志 Vdx o  
public static void log(String sMsg) `r-Jy{!y4  
{ v JGH8$%;,  
System.err.println(sMsg); /huh}&NNu  
} FCEmg0qdjD  
"Y L^j~A  
t?-a JU  
public static void log(int sMsg) d3q.i5']G  
{ Qd YYWD   
System.err.println(sMsg); u28$V]  
} JD0s0>q_  
} aV|V C $  
cL*oO@I&_  
9#P~cW?  
/* y7:f^4  
**TestMethod.java n.8870.BW  
*/ ![ce }  
package NetFox; y[.lfW?)  
EGqu-WBS  
UakVmVN/P  
public class TestMethod { C=r`\W  
)#i"hnYpQ  
Y% \3N  
public TestMethod() beikzuC  
{ ///xx/weblogic60b2_win.exe HP_h!pvx  
try{ )e'F[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #z&R9$  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 6M7GPHah  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0n6eWwY  
fileFetch.start(); R[l`# I  
}  w (RRu~J  
catch(Exception e){e.printStackTrace ();} GB}\7a  
HAI) +J   
% vy,A*  
} Gr&e]M[l  
de2G"'F  
fi>.X99(G  
public static void main(String[] args) 7Ko*`-p  
{ 'D`lVUB  
new TestMethod(); qGV(p}$O  
} B,_K mHItd  
} E_A5KLP  
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