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http断点续传简单实现(java)

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/* K~]Xx~F  
**SiteFileFetch.java 6(\-aH'Ol  
*/ f dJg7r*  
package NetFox; }x{1{Bw>Y  
import java.io.*; Gyy4)dP  
import java.net.*; .FYRi_Zd  
.0>bnw  
?l[#d7IB  
public class SiteFileFetch extends Thread { ?N+pWdi  
wBI:}N@.  
kyJKai  
SiteInfoBean siteInfoBean = null; //文件信息Bean B~Z61   
long[] nStartPos; //开始位置 i+Ne.h  
long[] nEndPos; //结束位置 1 h162  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \\Zsxya1  
long nFileLength; //文件长度 ?=?*W7  
boolean bFirst = true; //是否第一次取文件 @G=:@;  
boolean bStop = false; //停止标志 Ir` l*:j$  
File tmpFile; //文件下载的临时信息 $D^27q:H  
DataOutputStream output; //输出到文件的输出流 bQ?Vh@j(M  
)g&nI <Mh  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) !oRN,m[7)p  
public SiteFileFetch(SiteInfoBean bean) throws IOException Rc@lGq9  
{ SRHD"r^@  
siteInfoBean = bean; 3<Z@!ft8  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); hOqNZ66{  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 55y}t%5  
if(tmpFile.exists ()) -)"\?+T  
{ } ?+0s=Z  
bFirst = false; t=fAG,k5  
read_nPos(); q?w%%.9]X  
}  KI\ 9)  
else oY\;KPz  
{ D+BflI~9mP  
nStartPos = new long[bean.getNSplitter()]; ;8]Hw a1!  
nEndPos = new long[bean.getNSplitter()]; o9{1_7K  
} {j[*:l0Ui  
'oBv(H  
tnX W7ej^  
/HSg)  
} N>j*{]OY+{  
% 5!Y#$:{o  
#LYx;[D6  
public void run() Me+)2S 9  
{ nwDW<J{f|U  
//获得文件长度 v9D[| 4  
//分割文件 t/]za4w/  
//实例FileSplitterFetch Ac>G F  
//启动FileSplitterFetch线程 mL@7,GD  
//等待子线程返回 o:%;AOcl  
try{ Nc(A5*  
if(bFirst) Ys5I qj=mp  
{ :bP <H  
nFileLength = getFileSize(); 'Te'wh=Y  
if(nFileLength == -1) M%eTNsbNm  
{ :r_/mzR#  
System.err.println("File Length is not known!"); 5e'**tbKH  
} rqM_#[Y?  
else if(nFileLength == -2) $yZP"AsAR  
{ f*[Uq0?  
System.err.println("File is not access!"); ;4vx+>-  
} 4d-"kx3X  
else m?)F@4]  
{ yA<\?Ps  
for(int i=0;i<nStartPos.length;i++) !`dn# j  
{ pWGIA6&v(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); I\6^]pi,  
} ZN`I4Ak  
for(int i=0;i<nEndPos.length-1;i++) s.!gsCQme  
{ A6F/w  
nEndPos = nStartPos[i+1]; `9VRT`e  
} i~*#z&4A+  
nEndPos[nEndPos.length-1] = nFileLength; 4V5h1/JPm  
} A@G%*\UZ  
} *i7|~q/u  
(Mt-2+"+  
n\4sNoFI  
//启动子线程 vQ DlS1L  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !o`h*G-x  
for(int i=0;i<nStartPos.length;i++) vj<JjGP  
{ wb-_CQ  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Qnv)\M1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ca$K)=cDW  
nStartPos,nEndPos,i); SfwNNX%  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?xCWg.#l4V  
fileSplitterFetch.start(); y$HV;%G{26  
} 8<X; 8R  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D3;#:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); `CEHl &w  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", <8 25?W|  
nEndPos = " + nFileLength); 'di(5  
// fileSplitterFetch[nPos.length-1].start(); ;XGO@*V5T  
w:[\G%yQ  
e[L%M:e9U  
//等待子线程结束 N/N~>7f  
//int count = 0; [-JU(:Rh  
//是否结束while循环 yK:b $S  
boolean breakWhile = false; rW0-XLbL5H  
.OSFLY#[?  
%8g1h)F"S  
while(!bStop) V82N8-l  
{ </jTWc'}  
write_nPos(); IkJ-*vI6  
Utility.sleep(500); Ya-kM UW  
breakWhile = true; @  M  
8{4jlL;"`?  
xr1,D5  
for(int i=0;i<nStartPos.length;i++) Ex}hk!  
{ P jh3=Dr  
if(!fileSplitterFetch.bDownOver) 0ZJt  
{ [$%O-_x  
breakWhile = false; ^;a~_9 m-  
break; #>dj!33  
} zP|^) h5  
} |t uh/e@dx  
if(breakWhile) ^s?=$&8f![  
break; xv>]e <":  
MI\35~JAN  
Q6rvTV'vv  
//count++; `ehcj G1nY  
//if(count>4)  &'<e9  
// siteStop(); D $3Mg  
} j NkobJ1  
.I nDyKt  
'nSo0cyQ  
System.err.println("文件下载结束!"); b,uu dtlH  
} I::|d,bR!  
catch(Exception e){e.printStackTrace ();} ?]PE!7H  
} 'Uu!K!  
3  G_0DS  
0Tq=nYZA  
//获得文件长度 :B  9>  
public long getFileSize() ?Es(pwJB  
{ On-zbE  
int nFileLength = -1; M2lvD&  
try{ T1#r>3c\  
URL url = new URL(siteInfoBean.getSSiteURL()); |Q?^Ba  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hU6oWm  
httpConnection.setRequestProperty("User-Agent","NetFox"); chA7R'+LA  
&$g{i:)Z  
x7ZaI{    
int responseCode=httpConnection.getResponseCode(); +FJ+,|i  
if(responseCode>=400) w?:tce   
{ (NC]S  
processErrorCode(responseCode); IRyZ0$r:e\  
return -2; //-2 represent access is error h5<eU;Rw+  
} |wINb~trz  
.C,D;T{  
#pcgfVl  
String sHeader; ?"$Rw32  
6|n3e,&A2  
0TWd.+  
for(int i=1;;i++) QTC!vKM  
{ oju,2kpH7#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -}(2}~{e(  
//Utility.log(in.readLine()); <.".,Na(J0  
sHeader=httpConnection.getHeaderFieldKey(i); JIPBJ  
if(sHeader!=null) Z7XFG&@6  
{ Q$(Fm a4a  
if(sHeader.equals("Content-Length")) pZz\o  
{ {$g3R@f^~  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L3=5tuQ[5  
break; =;"=o5g_  
} &-Ylj  
} lg +>.^7k  
else F3[,6%4v  
break; LUdXAi"f  
} wJj:hA}  
} _&%FGcAS  
catch(IOException e){e.printStackTrace ();} 6H=gura&   
catch(Exception e){e.printStackTrace ();} S$ffTdRz  
F3hG8YX  
gxx#<=`  
Utility.log(nFileLength); (x fN=Te,-  
y @S_CB 47  
NfUt\ p*  
return nFileLength; "}V_.I* +  
} DD2K>1A1  
V';l H2  
H@1}_d  
//保存下载信息(文件指针位置) K)U[xS;<  
private void write_nPos() vA}_x7}n(  
{ gB~^dv {  
try{ 5vg="@O K  
output = new DataOutputStream(new FileOutputStream(tmpFile)); bf|ePGW?  
output.writeInt(nStartPos.length); A,BYi$  
for(int i=0;i<nStartPos.length;i++) f}J(nz>Sh  
{ FWA?mde  
// output.writeLong(nPos); sQe GT)/|  
output.writeLong(fileSplitterFetch.nStartPos); \ 'Va(}v  
output.writeLong(fileSplitterFetch.nEndPos); 2,wwI<=E'  
} vd)zvI  
output.close(); z$WLx  
} SnR2o3r-Of  
catch(IOException e){e.printStackTrace ();} }opw_h+/F  
catch(Exception e){e.printStackTrace ();} 4hODpIF  
} 0Ni{UV? k  
GX0zirz  
_&/ {A|n  
//读取保存的下载信息(文件指针位置) M(zZ8#  
private void read_nPos() xEk8oc  
{ S>r",S  
try{ ~`C _B]3|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); !nCq8~#  
int nCount = input.readInt(); ?*%_:fB  
nStartPos = new long[nCount]; !Av9 ?Q:  
nEndPos = new long[nCount]; X.#)CB0c1Q  
for(int i=0;i<nStartPos.length;i++) U2A 82;Z  
{ H#DvCw  
nStartPos = input.readLong(); c~?Zmdn:  
nEndPos = input.readLong(); s<)lC;#e  
} 0'fswa)  
input.close(); kJp~'\b  
} c#sHnpP  
catch(IOException e){e.printStackTrace ();} &8z<~q  
catch(Exception e){e.printStackTrace ();} dw3Hk$"h  
} P=5+I+  
~e 1l7H;  
{VL@U$'oI  
private void processErrorCode(int nErrorCode)  7P7OTN  
{ 8.#{J&h  
System.err.println("Error Code : " + nErrorCode); 0n}13u=}  
} m&Mupl  
G$+v |z  
k=hWYe$iAz  
//停止文件下载 DzQBWY] )  
public void siteStop() +t+<?M B  
{ \ph.c*c  
bStop = true; 4 "HX1qP  
for(int i=0;i<nStartPos.length;i++) K"H\gmV_ g  
fileSplitterFetch.splitterStop(); \A"o[A2v  
9)ALJd,M  
_!R$a-  
} }OL"38P  
} 3KkfQ{  
//负责部分文件的抓取 KLg1(W(  
**FileSplitterFetch.java rP3HR 5  
*/ UJ)pae  
package NetFox; K>@yk9)vi  
En?V\|,  
HYmC3  
import java.io.*; ?Gki0^~J  
import java.net.*; bf"'xn9  
/x6p  
\^c4v\s<o#  
public class FileSplitterFetch extends Thread { D(#f`Fj;  
q8v[u_(yD  
*?rWS"B  
String sURL; //File URL qN)y-N.LI(  
long nStartPos; //File Snippet Start Position 3'0Pl8  
long nEndPos; //File Snippet End Position pk/#RUfT+  
int nThreadID; //Thread's ID Nr~$i%[  
boolean bDownOver = false; //Downing is over vk& gR  
boolean bStop = false; //Stop identical Ke\\B o,  
FileAccessI fileAccessI = null; //File Access interface N+|NI?R?}  
Tlsh[@Q  
lLx!_h  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException >='/%Ad  
{ <'a~Y3B"o  
this.sURL = sURL; U(#<D7}  
this.nStartPos = nStart; I0Pw~Jj{  
this.nEndPos = nEnd; :v&[ !  
nThreadID = id; b(H{i}{]  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ps!MpdcL3  
} 1- KNXGb'  
tIsWPt]Y  
iC gZ3M]  
public void run() yB b%#GW  
{ wVs?E  
while(nStartPos < nEndPos && !bStop) >XD?zF)6  
{ > ;,S||  
nw+~:c  
Bt+^H6cb  
try{ U v2.Jo/Q  
URL url = new URL(sURL); h0GoF A<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 3o<d= @`r  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4T@:_G2b  
String sProperty = "bytes="+nStartPos+"-"; N9e'jM>Oos  
httpConnection.setRequestProperty("RANGE",sProperty); q2qi~}l  
Utility.log(sProperty); g{8RPw]  
DXFu9RE\{  
{ i5?R,a)  
InputStream input = httpConnection.getInputStream(); oxwbq=a6yV  
//logResponseHead(httpConnection); @T'^V0!-q:  
1 ^~&"s U  
"HMEoZ  
byte[] b = new byte[1024]; *;7y5ZJ  
int nRead; (m~>W"x/  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b/SBQ" B%  
{ 8:ubtB  
nStartPos += fileAccessI.write(b,0,nRead); ewZ?+G+m  
//if(nThreadID == 1) Kl1v^3\{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w_9^YO! !  
} `KJ( .m  
,6)N.  
TBj2(Z  
Utility.log("Thread " + nThreadID + " is over!"); DeO-@4+qKd  
bDownOver = true; @= -(H<0  
//nPos = fileAccessI.write (b,0,nRead); Y-VDi.]W  
} W^(zP/  
catch(Exception e){e.printStackTrace ();} pwFp<O"  
} ^QK`z@B  
} om3 %\  
`MtzA^Xr  
L\:|95Yq  
//打印回应的头信息 rTPgHK]?l  
public void logResponseHead(HttpURLConnection con) 3Cf9'C  
{ &?<uR)tl  
for(int i=1;;i++) LUOjaX  
{ ]\E"oZ  
String header=con.getHeaderFieldKey(i); y Zaf q"o  
if(header!=null) vygzL U^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); "J VIkC  
Utility.log(header+" : "+con.getHeaderField(header)); bLqy7S9x  
else .<x6U*)\O  
break; ~Y 6'sM|  
} *ap,r&]#F  
} -Q WvB  
]\, ?u /  
x|H`%Z  
public void splitterStop() 4TtC~#D:  
{ Gh;\"Qx  
bStop = true; qmS9*me {  
} ,jU>V]YC  
yD\q4G  
Tz @<hE  
} m`yvZ4K!  
i7x&[b  
~7m`p3W@  
/* c%&,(NJ]K  
**FileAccess.java ]'.qRTz'\t  
*//文件访问(定位,写) Y teIp'T  
package NetFox; `3TR`,=  
import java.io.*; {K^5q{u  
'L/)9.29  
26V6Y2X  
public class FileAccessI implements Serializable{ g2OnLEF]s  
$LP(\T([  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }m:paB"3  
RandomAccessFile oSavedFile; x39tnf/F  
long nPos; ,NO[Piok  
Bm~^d7;Cw  
hY)zKX_r  
public FileAccessI() throws IOException &4Z8df!  
{ r=j?0k '}]  
this("",0); >+O0W)g{o  
} b8!oZ~ K  
|nMjv]#  
}Qo]~/  
public FileAccessI(String sName,long nPos) throws IOException 0\mf1{$"!7  
{ Fe8X@63  
oSavedFile = new RandomAccessFile(sName,"rw"); z~{08M7  
this.nPos = nPos; g;l K34{  
oSavedFile.seek(nPos); ; _%zf5;'  
} GMU!GSY  
\8(Je"S  
:tWk K$  
public synchronized int write(byte[] b,int nStart,int nLen) xI,3(A.  
{ }B%9cc  
int n = -1; d=1\=d/K  
try{ W @"Rdc-  
oSavedFile.write(b,nStart,nLen); RHsVG &<j  
n = nLen; FQek+[ox  
} A&}]:4@{  
catch(IOException e) 1 |z4]R,<  
{ J;sQvPHV8  
e.printStackTrace (); '`8 ^P  
} % J\G[dl  
65Z}Hf  
<*vR_?!  
return n; p3_ Qx  
} RIkIE=+6  
\p:)Cdn  
rDl/R^w"  
} o0WwlmB5  
SY95s  
4{>r_^8  
/* OX,em Ti  
**SiteInfoBean.java .QY>@b\  
*/ A":=-$)  
package NetFox; hq"n RH  
IAA_Ft  
27}:f?2hbJ  
public class SiteInfoBean { &wQ<sVQ0$  
r@JMf)a]  
PY|zN|  
private String sSiteURL; //Site's URL R(t%/Hvs$  
private String sFilePath; //Saved File's Path FM%WMyb[  
private String sFileName; //Saved File's Name |keU+De  
private int nSplitter; //Count of Splited Downloading File 6Takx%U  
dkC_Sh{  
U| yt   
public SiteInfoBean() h0-.9ym  
{//nSplitter的缺省值为5 ju:}%'  
//default value of nSplitter is 5 _9-;35D_  
this("","","",5); 3 85qQppz  
} _I)TO_L;  
p7+>]sqX  
6r^ZMW  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `]]m$  
{ YS4"TOFw  
sSiteURL= sURL; =f@71D1  
sFilePath = sPath; ;+DMv5A "  
sFileName = sName; ZYY`f/qi  
this.nSplitter = nSpiltter; _e8Gt6>  
`C7pM  
K}q5,P(  
} E*R-Dno_F  
g[y&GCKY!=  
nzO -\`40  
public String getSSiteURL() ?gu!P:lZS  
{ @WXRZEz  
return sSiteURL; F)=<|,b1  
} 1z; !)pG.  
5T"h7^}e  
O*2{V]Y @  
public void setSSiteURL(String value) (^T}6t3+4  
{ jn]l!nm  
sSiteURL = value; AN,3[Sh  
} FYNUap,A  
j0F& WKk  
R {-M%n4w  
public String getSFilePath() sw$JY}Q8x  
{ R0w~ Z   
return sFilePath; M~X~2`fFH  
} l"&iSq!3=  
W`[7|8(6!  
sj+ )   
public void setSFilePath(String value) H>\l E2  
{ }If,O  
sFilePath = value; $/u.F;  
} )+)qFGVz  
0/fwAp  
/^i_tLgb  
public String getSFileName() 17:7w  
{ 9e;{o,r@  
return sFileName; t}K8{ V  
} G]-\$>5R  
mmC MsBfL  
\*fXPJ4  
public void setSFileName(String value) fTy{`}>  
{ gYpFF=7j<@  
sFileName = value; Kk% I N9  
} m9'bDyyK  
$?&distJ  
wLq#,X>%B  
public int getNSplitter() T[ zEAj  
{ 5uM`4xkj  
return nSplitter; ;P8.U(  
} Fe2iG-ec  
<P5 7s+JK  
%u?A>$Jn  
public void setNSplitter(int nCount) M\08 7k  
{ }dq)d.c  
nSplitter = nCount; H/0b3I^  
} R|\kk?,u  
} AB.ZmR9|  
bz\nCfU  
oJc v D  
/* 9 KU3)%U  
**Utility.java :Q;mgHTNz  
*/ y<ZT~e  
package NetFox; A2nL=9~   
V4<f4|IL  
:<6gP(  
public class Utility { ZyrVv\'  
2 o5u02x  
2Gc0pBqx  
public Utility() %G, d&%f  
{ .|LY /q\A  
ZGS4P0$  
)5<c8lzp  
} 8J0#lu  
E7U.>8C  
//线程睡眠 l Ztw[c  
public static void sleep(int nSecond)  )jH|j  
{ XAUHF-"WE  
try{ 2()/l9.O'  
Thread.sleep(nSecond); <xD6}h/  
} t|59/R  
catch(Exception e) N}\3UHtO  
{ X> V`)  
e.printStackTrace (); Gr|102  
} HA;G{[X  
} d?jzh 1  
GOY!()F  
//日志 Z7=k$e  
public static void log(String sMsg) xU;Q ~(  
{ }\.Z{h:t ?  
System.err.println(sMsg); 7HQ|3rt  
} 10..<v7  
oN.#q$\` k  
RA:3ZV  
public static void log(int sMsg) e8hwXz  
{ >^adxXw.o  
System.err.println(sMsg); {Nny .@P)H  
} 7G &I]>  
} yq\p%z$:  
(b;*8  
6%fF6  
/* &265 B_'D  
**TestMethod.java "/$2oYNy+  
*/ 4{Af 3N  
package NetFox; [BKX$A:Y  
\[W)[mH_  
NmZowh$M  
public class TestMethod { rnS&^  
b=Oec%Adx  
;n;bap  
public TestMethod() s(s hgI 3g  
{ ///xx/weblogic60b2_win.exe _Xzl=j9[  
try{ ^Qa!{9o[  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); y-#01Z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;]sbz4?  
SiteFileFetch fileFetch = new SiteFileFetch(bean); [mA\,ny9  
fileFetch.start(); (|.rEaTA[1  
} .%T.sQ  
catch(Exception e){e.printStackTrace ();} OCN@P+L3q  
Mib<1ZM  
8AuOe7D9A  
} ZBl!7_[_  
e)A-.SRiO$  
U6yZKK  
public static void main(String[] args) w4(g]9^Q  
{ 'fr~1pmx#3  
new TestMethod(); H&E3RU> `  
} ^%jk.*  
} F%^)oQT+c  
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