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http断点续传简单实现(java)

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/* H@GE)I>^@  
**SiteFileFetch.java 5F2_xH$5  
*/ U&X2cR &a  
package NetFox; YutQ]zYA.  
import java.io.*; @5xu>gKn  
import java.net.*; (Yv{{mIy  
B MM--y@  
T-'~?[v  
public class SiteFileFetch extends Thread { ;f:gX`"\  
^i+[m  
]jyM@  
SiteInfoBean siteInfoBean = null; //文件信息Bean @Br {!#Wf  
long[] nStartPos; //开始位置 [E7MsX  
long[] nEndPos; //结束位置 d+;gw*_Ei  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 O gmSQ  
long nFileLength; //文件长度 DECB*9O ^  
boolean bFirst = true; //是否第一次取文件 LXj5R99S  
boolean bStop = false; //停止标志 8$0\J_  
File tmpFile; //文件下载的临时信息 wJe?t$ac?  
DataOutputStream output; //输出到文件的输出流 |~WYEh  
UUeB;'E+  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) /@hJpz|+   
public SiteFileFetch(SiteInfoBean bean) throws IOException Q $~n/  
{ [:iv4>ZZ  
siteInfoBean = bean; 3GF2eS$$P  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !SO8O  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); b O=yi)  
if(tmpFile.exists ()) +L0w;wT  
{ F30 ]  
bFirst = false;  W^Y#pn  
read_nPos(); mk!Dozb/  
} !4WEk  
else T dk ,&8  
{ 5{K}?*3hJ  
nStartPos = new long[bean.getNSplitter()]; a8pY[)^c  
nEndPos = new long[bean.getNSplitter()]; ](#&.q%5!  
} ib$nc2BPb  
[84F0 9HU  
T-gk<V  
g JjN<&,  
} }XR : 2  
.m;G$X|3U  
)55\4<ty  
public void run() bUZ_UW  
{ `pL^}_>|GM  
//获得文件长度 i%-Ld Ka}"  
//分割文件 Tde0~j}  
//实例FileSplitterFetch ]E3<UR  
//启动FileSplitterFetch线程 .$!{-v[  
//等待子线程返回 eS'yGY0b  
try{ $bvJTuw  
if(bFirst) ,lt8O.h-l  
{ t 9^A(Vh"-  
nFileLength = getFileSize(); FY'ty@|_s  
if(nFileLength == -1) 2 rN ,D(  
{ #aar9  
System.err.println("File Length is not known!"); AVl~{k|  
} M6rc!K  
else if(nFileLength == -2) Qd &" BEs  
{ 9MY7a=5E~  
System.err.println("File is not access!"); L?5f+@0.  
} \( )# e  
else }7s>B24J  
{ HfB@vw^  
for(int i=0;i<nStartPos.length;i++) OtTBErQNF  
{ 5GQLd  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); >9H@|[C  
} X[](Kj^`<  
for(int i=0;i<nEndPos.length-1;i++) nXA\|c0  
{ F%d \~Vj  
nEndPos = nStartPos[i+1]; VsK>6S\T  
} a|4~NL  
nEndPos[nEndPos.length-1] = nFileLength; C3'rtY.  
} R@iUCT^$  
} =IU*}>#  
\.uc06  
wQ+8\ s=  
//启动子线程 lFSe?X^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p|+B3  
for(int i=0;i<nStartPos.length;i++) $t~@xCi]S  
{ 0d^Z uTN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l;A,0,i  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p\p\q(S">  
nStartPos,nEndPos,i); l?8M p$M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r?/A?DMe  
fileSplitterFetch.start(); /) 4GSC}Gg  
} 1f'Hif*r_X  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Wg`AZ=t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); tK(g-u0N`(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^|!I +  
nEndPos = " + nFileLength); c{+AJ8  
// fileSplitterFetch[nPos.length-1].start(); }8-\A7T  
? "/ fPV-  
Iu@y(wyg  
//等待子线程结束 w Y   
//int count = 0; SqA J-_~  
//是否结束while循环 A{eLl  
boolean breakWhile = false; S8d8%R~1=h  
"=. t 36#  
20RXK1So  
while(!bStop) V'Kgdj  
{ ;%C'FV e]  
write_nPos(); ~PWSo%W8  
Utility.sleep(500); =sJ _yq0#R  
breakWhile = true; wC_l@7 t  
lbdTQ6R  
 +=q)  
for(int i=0;i<nStartPos.length;i++) G!N{NCq  
{ iIT8H\e  
if(!fileSplitterFetch.bDownOver) (>4aibA'P  
{ A>`945|  
breakWhile = false; Kv'n:z7Md  
break; fWc|gq  
} \c v?^AI  
} 57a2^  
if(breakWhile) &3F}6W6A  
break; IQ< MyB(  
.nu @ o40  
aI(7nJ=R  
//count++; !Z!g:II /  
//if(count>4) Migd(uw'  
// siteStop(); <ljI;xE  
} D\w h;r  
`\`>0hlu  
n79QJl/  
System.err.println("文件下载结束!"); 9SlNq05G7  
} 7]xm2CHx5  
catch(Exception e){e.printStackTrace ();}  T9)nQ[  
} FLg*R/  
FGO[ |]7IN  
S##1GOO  
//获得文件长度 >Rvx[`|O!m  
public long getFileSize() ;6@r-r  
{ 0]QRsVz+  
int nFileLength = -1; |@,|F:h<M  
try{ HEL!GC>#  
URL url = new URL(siteInfoBean.getSSiteURL()); aQ^umrj@?9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); T=hho Gn  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~\x:<)  
(,^*So/  
6sIL.S~c)  
int responseCode=httpConnection.getResponseCode(); #&v/icz$  
if(responseCode>=400) `%+ mO88o  
{ ,+`61J3W  
processErrorCode(responseCode); #;n +YM">:  
return -2; //-2 represent access is error 4Mk-2 Dx  
} hcVJBK  
:o:e,WKxb  
^F?&|clM/  
String sHeader; cvwhSdZu8  
eC5$#,HiC  
Z/rP"|EuQ  
for(int i=1;;i++) | mu+9   
{ dU\%Cq-G)  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ARcv;H 5  
//Utility.log(in.readLine()); eEhr140  
sHeader=httpConnection.getHeaderFieldKey(i); 7~#:>OjW  
if(sHeader!=null) q+B&orp  
{ ,=?{("+  
if(sHeader.equals("Content-Length")) +[SgO}sF  
{ @EE."T9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 8M@BG8  
break; XZw6Xtn  
} x `V;Y]7'  
} ;3_l@dP"  
else 4v[~r1!V  
break; ''\;z<v   
} 8kP3+  
} ?\8?%Qk  
catch(IOException e){e.printStackTrace ();} UT}i0I9  
catch(Exception e){e.printStackTrace ();} wP"dZagpj  
EGl^!.'  
"UwH\T4I  
Utility.log(nFileLength); czlFr|O;  
,lCgQ0}<  
xkOpa,=FI  
return nFileLength; 5>AX*]c  
} T{wuj[ Q#:  
u&wiGwF[  
)Ud-}* g  
//保存下载信息(文件指针位置) L@JOGCYy  
private void write_nPos() W2uOR{ '?  
{ #07gd#j4  
try{ :!zl^J;  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 5q "ON)x  
output.writeInt(nStartPos.length); DWdW,xG  
for(int i=0;i<nStartPos.length;i++) _)]CzBRq\6  
{ !x'/9^i~v  
// output.writeLong(nPos); Z,iHy3`  
output.writeLong(fileSplitterFetch.nStartPos); d#2$!z#  
output.writeLong(fileSplitterFetch.nEndPos); ')GSAY7  
} m|OO,gR  
output.close(); q&:=<+2"  
} 2Pc%fuC  
catch(IOException e){e.printStackTrace ();} /  g 2b  
catch(Exception e){e.printStackTrace ();} }MUn/ [x  
} JI vo_7{  
NWxUn.Gy9  
O9:U8$*  
//读取保存的下载信息(文件指针位置) ?ve#} \  
private void read_nPos() NY?;erX  
{ dK>7fy;mv  
try{ |F#1C9]P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }`+B=h-dW  
int nCount = input.readInt(); 'w1YFdW  
nStartPos = new long[nCount]; 1{P'7IEj  
nEndPos = new long[nCount]; ? R>h `  
for(int i=0;i<nStartPos.length;i++) {/pm<k=  
{ d|4}obCt  
nStartPos = input.readLong(); "W(Q%1!Wi  
nEndPos = input.readLong(); *}8t{ F@k  
} [LRLJ_~g5  
input.close(); M`S0u~#tI  
} .H,xle  
catch(IOException e){e.printStackTrace ();} 8zMu7,E  
catch(Exception e){e.printStackTrace ();} IT$25ZF  
} \}]!)}G  
O`vTnrY  
Zkf0p9h\  
private void processErrorCode(int nErrorCode) $[yFsA6  
{ `7H4Y&E  
System.err.println("Error Code : " + nErrorCode); yeHDa+}  
} VWO9=A*Y|  
o: ;"w"G  
0 Us5  
//停止文件下载 Qqlup  
public void siteStop() ":_vK}5  
{ 2=_g f  
bStop = true; "9n3VX)  
for(int i=0;i<nStartPos.length;i++) $HJwb-I  
fileSplitterFetch.splitterStop(); R"K#7{p9  
GaSPJt   
c*@G_rb  
} QD%L0;j  
} im @h -A]0  
//负责部分文件的抓取 L QjsOo  
**FileSplitterFetch.java yBI'djL~>  
*/ T*KMksjxm`  
package NetFox; Z> r^SWL  
5# K4bA  
%AQIGBcgL  
import java.io.*; $1v&azM.  
import java.net.*; H#ncM~y*  
L5,NP5RC  
P@FHnh3}Z$  
public class FileSplitterFetch extends Thread { DY^;EZ!hb  
AFAAuFE"  
QV\eMuNy  
String sURL; //File URL ` Jdb;  
long nStartPos; //File Snippet Start Position ~s5SZK*  
long nEndPos; //File Snippet End Position RSo& (Uv  
int nThreadID; //Thread's ID 9:M` j  
boolean bDownOver = false; //Downing is over ^_m9KA  
boolean bStop = false; //Stop identical YY!Rz[/  
FileAccessI fileAccessI = null; //File Access interface ]KmO$4  
"&3h2(#%  
~ yX2\i"  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException KGg3 !jY  
{ +>PX&F  
this.sURL = sURL; 6 :~v4W!k  
this.nStartPos = nStart; )P+7PhE{J  
this.nEndPos = nEnd; !50[z:  
nThreadID = id; IC7M$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [Vma^B$7Vj  
} ,{mCf ^  
?Ec7" hK  
)Eo)t>  
public void run() K>{T_){  
{ Gn&4V}F  
while(nStartPos < nEndPos && !bStop) !@v7Zu43,  
{ @mfEKU!  
^f(@gS}?  
V 0rZz  
try{ 4F{70"a  
URL url = new URL(sURL); GP#aya  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8e(\%bX  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0vw4?>Jf@  
String sProperty = "bytes="+nStartPos+"-"; VTH> o>g  
httpConnection.setRequestProperty("RANGE",sProperty); >qF CB\(  
Utility.log(sProperty); ^- d%r  
-(=eM3o-9m  
3p'I5,}  
InputStream input = httpConnection.getInputStream(); ^N)R=tl  
//logResponseHead(httpConnection); gdQvp=v]  
zOiu5  
1Yn +<I  
byte[] b = new byte[1024]; Pjc Tx +  
int nRead; H/37)&$E(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) J_4!2v!6e  
{ FIsyiSY<j  
nStartPos += fileAccessI.write(b,0,nRead); kbe-1 <72  
//if(nThreadID == 1) {Ja!~N;3  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1|jt"Hz  
} )<tI!I][j  
KGFv"u{  
;4pYK@9w_  
Utility.log("Thread " + nThreadID + " is over!"); q0zr E5  
bDownOver = true; G2T|RT $_K  
//nPos = fileAccessI.write (b,0,nRead); n~V ]Z  
} uu>Pkfo  
catch(Exception e){e.printStackTrace ();} @8I4[TE  
} uwy:t!(j  
} <Pi|J-Y  
_+E5T*dk  
ilqy /fL#  
//打印回应的头信息 (:> ,u*x%  
public void logResponseHead(HttpURLConnection con) av|g}xnj  
{ ?snp8W-WB  
for(int i=1;;i++) 4v{o  
{ Ob<{G"  
String header=con.getHeaderFieldKey(i); :Nz2z[W$  
if(header!=null) =7m)sxj]w  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ~o~!+`@q  
Utility.log(header+" : "+con.getHeaderField(header)); pW J Fz-  
else V: TM]  
break; L bmawi^  
} JVSA&c%3  
} ybKWOp:O  
lE(a%'36  
W~7A+=&  
public void splitterStop() LF& z  
{ @y\X R  
bStop = true; i=oU;7~zK  
} 5l UF7:A>#  
%#xaA'? [  
!'9Feoez  
} 9~/J35  
<"my^  
R[hzMU}KB  
/* 4J/}]Dr5  
**FileAccess.java 7\s"o&G  
*//文件访问(定位,写) ?b>,9A.Z  
package NetFox; IHv[v*4:  
import java.io.*; 9^#c| 0T  
7%|~>  
}%{LJ}\Px  
public class FileAccessI implements Serializable{ ?q{ ,R"  
LQRQA[^  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 F7EKoDt  
RandomAccessFile oSavedFile; `3WFjU 5a  
long nPos; WGZ9B^A  
kr9*,E9cv  
%|q>pin2  
public FileAccessI() throws IOException sl`s_$J  
{ ~lsl@  
this("",0); 0vD7v  
} S]Mw #O|  
T^k7o^N>  
9Hb6nm  
public FileAccessI(String sName,long nPos) throws IOException tne ST.  
{ !C3MFm{B  
oSavedFile = new RandomAccessFile(sName,"rw"); |es?;s'  
this.nPos = nPos; PuA9X[=  
oSavedFile.seek(nPos); K1+)4!}%U  
} TE7nJ gm  
L>aLqQ3  
YSic-6z0Ms  
public synchronized int write(byte[] b,int nStart,int nLen) lJ}_G>GJ  
{ DpvI[r//'*  
int n = -1; L(|N[#  
try{ e]$}-i@#  
oSavedFile.write(b,nStart,nLen); 1Vrh4g.l  
n = nLen; QLvHQtzwX  
} qzKdQ&vO  
catch(IOException e) 2db3I:;E  
{ ZQ%'`q\c  
e.printStackTrace ();  ~- _kM  
} Gi?/C&1T  
V)~.~2$  
QSdHm  
return n; 7e|s wJ>4  
} [S9K6%w_!  
-$cmG4  
.ps-4eXF  
} yW1)vD7  
7XTkX"zKj  
8hOk{xs8  
/* _/-jX  
**SiteInfoBean.java 4U+xb>  
*/ 7vrl'^1  
package NetFox; |Mu p8(gCk  
[B#R94  
'MUv5 Th  
public class SiteInfoBean { 4ew" %Cs*  
N~goI#4  
(_mnB W  
private String sSiteURL; //Site's URL N`5,\TR2f  
private String sFilePath; //Saved File's Path )NXmn95  
private String sFileName; //Saved File's Name tl,.fjZn  
private int nSplitter; //Count of Splited Downloading File =[cS0Sy  
(|:M&Cna]  
vNV/eB8#S  
public SiteInfoBean() `.~N4+SP  
{//nSplitter的缺省值为5 Rg\z<wPBG  
//default value of nSplitter is 5 fk6%XO  
this("","","",5); A+ZK4]xb  
} la0BiLzb]  
([T>.s  
"d#Y}@*~o  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) #~}nFY.  
{ &C, 'x4c"  
sSiteURL= sURL; ZM !CaR  
sFilePath = sPath; 9kN}c<o  
sFileName = sName; B(LWdap~  
this.nSplitter = nSpiltter; ~:kZgUP_f  
S;3R S;  
/YP{,#p  
} sJ;g$TB  
vj'wm}/  
\qdHX  
public String getSSiteURL() s C%&cRQD  
{ 42_`+Vt]d7  
return sSiteURL; Neq+16*u  
} D/Z6C&/I  
X$ 0?j 1  
u]<,,  
public void setSSiteURL(String value) 5nv#+ap1 "  
{ C%$edEi  
sSiteURL = value; :)wy.r;N  
} bf ]f=;.+  
#^l L5=  
Vwg|K|  
public String getSFilePath() L[oui,}_  
{ D.B.7-_8  
return sFilePath; s @&`f{  
} 'y;EhOwj,  
sT3^hY7  
~ -4{B  
public void setSFilePath(String value) j"ThEx0  
{ lGPUIoUo  
sFilePath = value; Bn=by{i  
} f2Klt6"9  
1n >X[! 8x  
AF;)#T<  
public String getSFileName() rn/ /%  
{ <r .)hT"0  
return sFileName; bR*-Ht+wd  
} KyVQh8  
ocqU=^ta  
g`{;(/M+  
public void setSFileName(String value)  8{wwd:6  
{ 9oRy)_5Z(=  
sFileName = value; /[a~3^Gs^  
} q.KG^=10  
6Z>FTz_  
A>vBQN  
public int getNSplitter() UldXYtGe  
{ 2 Wt> Mi  
return nSplitter; "9ZID-~]  
} N=4G=0 `ke  
MW! srTQ_  
j`JMeCG=Ee  
public void setNSplitter(int nCount) V, Z|tB^  
{ iZ#!O* >  
nSplitter = nCount; ]{)a,c NG  
} aGrIQq/k)%  
} 1t:Q_j0Ym  
WK ts[Z  
bZnuNYty75  
/* p#01gB  
**Utility.java K,Ef9c/+K  
*/ ^!<U_;+  
package NetFox; l7XUXbYp&=  
!^^?dRd*v  
;;_,~pI?k  
public class Utility { eV 2W{vuI  
#+:9T /*>0  
8;d:-Cp  
public Utility() W3]_m8,Z  
{ 8qk?E6  
.GsV>H  
6 bomh2  
} X@$f$=  
j2Cks_$:  
//线程睡眠 n G,A@/N  
public static void sleep(int nSecond) 49rf7NT-g  
{ )_+rU|We  
try{ <>dT64R|  
Thread.sleep(nSecond); .R) D3NZp  
}  |XT)QK1  
catch(Exception e) D8inB+/-  
{ KX76UW   
e.printStackTrace (); HFKf kAl  
} ) brVduB  
} T_s _p  
Y#!UPhg<  
//日志 4E; VM{  
public static void log(String sMsg) [="e ziM{  
{ b=g8eMm  
System.err.println(sMsg); GQt8p[!  
} d:ARf  
O- ew%@_  
H2&@shOOQJ  
public static void log(int sMsg) N^#ZJoR  
{ M}`B{]lLz  
System.err.println(sMsg); 9 8j>1 "8  
} ~T ]m>A!  
} Z,RzN5eN  
O ,J>/  
8J=? 5  
/* .Obw|V-  
**TestMethod.java y[`l3;u:'  
*/ _a5d?Q9Z  
package NetFox; pf%=h |  
!g?|9  
`s"'r !  
public class TestMethod { _4rFEYz$d  
'[U8}z3  
=q>'19^Jx  
public TestMethod() >/:" D$  
{ ///xx/weblogic60b2_win.exe JI?rL  
try{ = 6tHsN23  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 5\N(PL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); M3J#'%$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?HTj mIb  
fileFetch.start(); SHvq.lYJ  
} Wl;.%.]>  
catch(Exception e){e.printStackTrace ();} 0@ yXi  
b o0^3]Z  
c]$i\i#  
} qHsUP;7  
, `wXg  
pM^9c7@!:  
public static void main(String[] args) Y&[1`:-~-  
{ ~res V  
new TestMethod(); :}yi -/_8!  
} @AK n@T5  
} JIOh#VNU  
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