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http断点续传简单实现(java)

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/* Y6CadC  
**SiteFileFetch.java >!oN+8[~  
*/ `=\G>#p<T  
package NetFox; Kc(_?`  
import java.io.*; c"QI`;D_c  
import java.net.*; MBg^U<t8  
^*0;Z<_  
=B/^c>w2  
public class SiteFileFetch extends Thread { ngNg1zV/q  
\q,w)BE  
`S.;&%B\  
SiteInfoBean siteInfoBean = null; //文件信息Bean %bv<OMD  
long[] nStartPos; //开始位置 A]n !d}?  
long[] nEndPos; //结束位置 #{]=>n)j  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Vxw?"mhP  
long nFileLength; //文件长度 M 35}5+  
boolean bFirst = true; //是否第一次取文件 aTPpE9Pa&  
boolean bStop = false; //停止标志 - -]\z*x  
File tmpFile; //文件下载的临时信息 ~#-`Qh  
DataOutputStream output; //输出到文件的输出流 "zv+|_ZAfd  
$]hf2Yr(  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ))MP]j9 T  
public SiteFileFetch(SiteInfoBean bean) throws IOException fG.w;Aemv5  
{ NyGF57v[M  
siteInfoBean = bean; bLUn0)c  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); hMDyE.X-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); D_8hn3FH  
if(tmpFile.exists ()) Jv7M[SJ#x  
{ {b+IDq`)=  
bFirst = false; =N3~2=g~A  
read_nPos(); Mr&]RTEE  
} gNO$WY^  
else ;J`X0Vl$  
{ ]f-e/8$`@  
nStartPos = new long[bean.getNSplitter()]; yn=1b:kid  
nEndPos = new long[bean.getNSplitter()]; fW\u*dMMZE  
} 'DIE#l`  
85X^T]zo  
5 )C~L]  
PzF)Vg  
} [Z[)hUXE?  
>,9t<p=Q  
5G2u(hx  
public void run() q`{.2yV  
{ UjfB+=7I{L  
//获得文件长度 sS0psw1  
//分割文件 >:K3y$]_  
//实例FileSplitterFetch c1z5t]d   
//启动FileSplitterFetch线程 N1SRnJu<f  
//等待子线程返回 / )EB~|4']  
try{ gF:wdcO  
if(bFirst) A^m hPBT_  
{ 0(..]\p^d  
nFileLength = getFileSize(); .Kv@p jOr  
if(nFileLength == -1) O}%=c\Pb  
{ <Q8bn?Z  
System.err.println("File Length is not known!"); _}\&;  
} : Z.mM5  
else if(nFileLength == -2) aRV!0?fS  
{ |g9^]bT  
System.err.println("File is not access!"); ]:f1r8<3p  
} Z@*Z@]FC  
else "q%)we  
{ Eod2vr =Q  
for(int i=0;i<nStartPos.length;i++) oL~Yrb%R  
{ ,`wxXU7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -Wig k['v  
} >B9rr0d0  
for(int i=0;i<nEndPos.length-1;i++) XrvrN^'  
{ LD5'4,%-  
nEndPos = nStartPos[i+1]; xNONf4I:6J  
} 4C2 D wj  
nEndPos[nEndPos.length-1] = nFileLength; WH/a#F  
} Ylf6-FbF  
} D~ {)\;w^!  
%:/;R_  
!l&lb]V cz  
//启动子线程 0r@rXwz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; G cbal:q  
for(int i=0;i<nStartPos.length;i++) Zaj<*?\  
{ d*G $qUiX  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), *[jaI-~S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), m]%cNxS  
nStartPos,nEndPos,i); |[V(u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =];FojC6I  
fileSplitterFetch.start(); 1H ZexV  
} j@:L MR>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4SOj>(a#  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]F_u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", S !e0 :  
nEndPos = " + nFileLength); ]f\rB8k|&  
// fileSplitterFetch[nPos.length-1].start(); o 1b#q/  
8=e \^Q+  
?@XO*|xkSk  
//等待子线程结束 *7Mrng  
//int count = 0; F%Xq}LMd  
//是否结束while循环 (O&b:D/Y  
boolean breakWhile = false; ;uJVY)7a  
\GkcK$Y  
6D+9f{~r  
while(!bStop) @3G3l|~>  
{ K>q,?x b  
write_nPos(); $@<\$I2s  
Utility.sleep(500); U-Iwda8v  
breakWhile = true; J|>P,x#G  
_Ih~'Y Fd  
abK/!m[q  
for(int i=0;i<nStartPos.length;i++) B^OhL!*tI  
{ fGxa~Unx  
if(!fileSplitterFetch.bDownOver) WT0U)x( m5  
{ b :+ X3  
breakWhile = false; F |GWYw'%  
break; `aUA_"f  
} i ^W\YLE  
} .d*vfE$  
if(breakWhile) g,1\Gj%y  
break; _7;#0B  
ru U|  
#8(@a Y  
//count++; 1]qhQd-u  
//if(count>4) C{,nDa?|  
// siteStop(); d9^h YS{  
} d2(n3Xf  
4v{gc/g  
t & ucq Y  
System.err.println("文件下载结束!"); B.{yf4a#L  
} ](O!6_'d  
catch(Exception e){e.printStackTrace ();} D4S>Pkv  
} %++q+pa  
QM$?}>:  
@U9ov >E  
//获得文件长度 Rk'pymap  
public long getFileSize() Xh{EItk~oO  
{ y@(U 6ZOyx  
int nFileLength = -1; +yYz;, \  
try{ ?2i``-|Wa  
URL url = new URL(siteInfoBean.getSSiteURL()); s5[ Cr"q7B  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ;+5eE`]a/L  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7[K$os5al  
%8v?dB;>x`  
Y/4B*>kl  
int responseCode=httpConnection.getResponseCode(); : |Z*aI]9  
if(responseCode>=400) Nc7YMxk'H  
{ VMNihx0FJ  
processErrorCode(responseCode); Y`_6Ny="  
return -2; //-2 represent access is error p3-sEIw}Ru  
} EBn7waBS  
-yC},tK  
_E1:3 N|  
String sHeader; .|rpj&>g  
LsLsSV  
eHv/3"Og  
for(int i=1;;i++) ^y?? pp<1J  
{ e06r5%|.%  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); VJPt/Dy{  
//Utility.log(in.readLine()); wWH5T}\  
sHeader=httpConnection.getHeaderFieldKey(i); \_+d*hHF~  
if(sHeader!=null) X2EC+<  
{ &< ~`?-c  
if(sHeader.equals("Content-Length")) jfI|( P  
{ N (43+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); @NNN&%  
break; V43 |Ej}E  
} u6D>^qF}@'  
} ~UL; O\-b0  
else f-3lJ?6  
break; PsTwJLY   
} qEywExdiu  
} J0{0B=d;  
catch(IOException e){e.printStackTrace ();} Er%nSH^"  
catch(Exception e){e.printStackTrace ();} 0uj3kr?cv  
k<AnTboa  
QYg2'`(  
Utility.log(nFileLength); x=9drKIw>  
Q.!D2RZc  
f>Ij:b`Z2  
return nFileLength; = i `o+H  
} oo /#]a  
n}YRE`>D  
[5,#p$R  
//保存下载信息(文件指针位置) 7q(RQQp  
private void write_nPos() k/*r2 C  
{ g<tr |n  
try{ -l^u1z  
output = new DataOutputStream(new FileOutputStream(tmpFile)); oo<,hOv   
output.writeInt(nStartPos.length); Bl(we/r  
for(int i=0;i<nStartPos.length;i++) t.3b\RV[  
{ l.FkX  
// output.writeLong(nPos); uNLA/hL+n  
output.writeLong(fileSplitterFetch.nStartPos); KecRjon~  
output.writeLong(fileSplitterFetch.nEndPos);  8*lVO2  
} %\CsP!  
output.close(); P0|V1,)  
} hX<0{pXM4  
catch(IOException e){e.printStackTrace ();} }+,;wj~  
catch(Exception e){e.printStackTrace ();} `vUilh ^c  
} z#*fELV  
>NK*$r8  
kJ{X5&,_  
//读取保存的下载信息(文件指针位置) EQMn'>  
private void read_nPos() %[5hTf  
{ s<aJ pi{n4  
try{ $(G.P!/  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); }ob#LC,  
int nCount = input.readInt(); XB^o>/|@S  
nStartPos = new long[nCount]; ;QS-a  
nEndPos = new long[nCount]; *ewE{$UpK  
for(int i=0;i<nStartPos.length;i++) tpU[KR[-  
{ bF<FX_}!s!  
nStartPos = input.readLong(); +A O(e  
nEndPos = input.readLong(); 0)+F}SyyD  
} 7<=xc'*8t  
input.close(); j$,:cN  
} Qv|A^%Ub!  
catch(IOException e){e.printStackTrace ();} 3D(/k%;)  
catch(Exception e){e.printStackTrace ();} R8sj>.I9j  
} 0M>+.}e+  
4uwI=UUB  
DFcgUEq  
private void processErrorCode(int nErrorCode) bU7n1pzW,o  
{ ol [   
System.err.println("Error Code : " + nErrorCode); !T!U@e=u  
} xhWWl(r`5  
;3'ta!.c  
:H@ Q`g u  
//停止文件下载 lmf vT}$B  
public void siteStop() GU([A@;  
{ z;J"3kM  
bStop = true; }CIH1q3P  
for(int i=0;i<nStartPos.length;i++) A_i=hj 2f  
fileSplitterFetch.splitterStop(); 9rf6,hF  
'H0uvvhOp  
il|e5TD^  
} )w4i0Xw^C:  
} V9mqJRFJ:  
//负责部分文件的抓取 (p>?0h9[  
**FileSplitterFetch.java TgoaEufS<  
*/ ]ri5mnB  
package NetFox; qs 6r9?KP  
Yw7txp`i  
Nawph  
import java.io.*; b bCH(fYbu  
import java.net.*; 6j/g/!9c!  
F0(P 2j  
JZ3CCf  
public class FileSplitterFetch extends Thread { rO[cm}  
9J+ p.N  
~4fUaMT  
String sURL; //File URL ;SnpD)x@)  
long nStartPos; //File Snippet Start Position 4YX/=  
long nEndPos; //File Snippet End Position /H3z~PBa  
int nThreadID; //Thread's ID 1DLAfsLlj  
boolean bDownOver = false; //Downing is over 6V-u<FJ  
boolean bStop = false; //Stop identical q!iS Y  
FileAccessI fileAccessI = null; //File Access interface :#7"SEud}  
e ?sMOBPlv  
nvY%{Zf$}  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \MI2^J N  
{ v#c'p^T  
this.sURL = sURL; Td(eNe_4T  
this.nStartPos = nStart; & 6 wD  
this.nEndPos = nEnd; W T~UEK'  
nThreadID = id; 79`OB##  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1 etl:gcEC  
} PDQEI55  
XB0G7o%1  
ut j7"{'k|  
public void run() Fj;];1nt  
{ H{ M7_1T  
while(nStartPos < nEndPos && !bStop) G5A:C(r  
{ \no6]xN;  
RGg=dN  
Rxb?SBa  
try{ 3u[m? Vw  
URL url = new URL(sURL); lDsT?yHS`Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); nQ*9E|Vx  
httpConnection.setRequestProperty("User-Agent","NetFox"); X\4d|VJ?m  
String sProperty = "bytes="+nStartPos+"-";  ddK\q!0  
httpConnection.setRequestProperty("RANGE",sProperty); iq1HA.X(  
Utility.log(sProperty); .bYZkO:oy  
/{Mo'.=Z  
03p D<  
InputStream input = httpConnection.getInputStream(); Jt ++3]  
//logResponseHead(httpConnection); -d>2&)5  
yxk:5L \A  
%B}<5iO  
byte[] b = new byte[1024]; >^:*x_a9  
int nRead; G.")Bg  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |#(KP  
{  A:b(@'h  
nStartPos += fileAccessI.write(b,0,nRead); 1aAY7Dm_&  
//if(nThreadID == 1) I%(YR"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); NTWy1  
} (/gv U80  
0Wkk$0h9  
,ArHS  
Utility.log("Thread " + nThreadID + " is over!"); \<ko)I#%  
bDownOver = true; / <C{$Gu  
//nPos = fileAccessI.write (b,0,nRead); IN8G4\r  
} lQl!TW"aO  
catch(Exception e){e.printStackTrace ();} )2sE9G,  
} S2i*Li  
} q]scKWYI  
^yLhL^Y  
/PZx['g  
//打印回应的头信息 v*";A  
public void logResponseHead(HttpURLConnection con) g ?.y7!m  
{ ]SC|%B_*  
for(int i=1;;i++) R?t_tmKXC!  
{ <uYrYqN  
String header=con.getHeaderFieldKey(i); 4%B0H>  
if(header!=null) #Z. QMWq  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); o;TS69|D  
Utility.log(header+" : "+con.getHeaderField(header)); VQ"Z3L3-4  
else !n7'TM '  
break; CZ 33|w  
} Kpg?' !I  
} ty8>(N(~  
,B~5;/ |  
57wHo[CJ  
public void splitterStop() 'aWqj+Wbh  
{ **V8a-@  
bStop = true; n!dXjInV  
} yJK:4af;.  
R 7h^ @  
[I?[N.v  
} G! Y l0Zr  
,&~-Sq) ~  
Ij>G7Q*d  
/* A` ~R\j  
**FileAccess.java i/ .#`  
*//文件访问(定位,写) =,b6yV+$D  
package NetFox; R-Ys<;  
import java.io.*; Q7.jSL6  
2YDD`:R  
w}]BJ<C  
public class FileAccessI implements Serializable{ Sse%~:FL  
7@&mGUALO  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9^u}~e #(  
RandomAccessFile oSavedFile;  J8-K  
long nPos; 7W'&v+\  
`?{6L#  
q`'m:{8  
public FileAccessI() throws IOException F EUfskv  
{ AGl#f\_^  
this("",0); /X]gm\x7s  
} s~QIs  
/Y=_EOS  
s3Wjhw/  
public FileAccessI(String sName,long nPos) throws IOException #<~oR5ddlb  
{ ZZw2m@T>  
oSavedFile = new RandomAccessFile(sName,"rw"); ~:L5Ar<  
this.nPos = nPos; #Iu "qu  
oSavedFile.seek(nPos); S{RRlR6Z  
} ,.kmUd  
QOX'ZAB`  
<5E)6c_W)  
public synchronized int write(byte[] b,int nStart,int nLen) :>}7^1I  
{ @SH[<c  
int n = -1; &q&~&j'[  
try{ $Zr \$z2  
oSavedFile.write(b,nStart,nLen); &pQ[(|=(  
n = nLen; h3bQ<?m  
} 7'OR ;b$  
catch(IOException e) b# Dd  
{ {Q>4zepN!  
e.printStackTrace (); >k ==7#P  
} cTz@ga;!mI  
yEMM@5W)8  
^*YoNd_kpN  
return n; LF `]=.Q  
} JMk2OK {0  
8[.&ca/[  
dt@~8kS  
} NT2XG& $W>  
kh@O_Q`j  
s2( 7z9jR  
/* ALn_ifNh  
**SiteInfoBean.java !rs }83w!  
*/ ]cv/dY#  
package NetFox; nrA 4N1  
ZeY|JH1  
z;?ztpa@  
public class SiteInfoBean { CDF;cM"td  
,{\Ae"{6  
aS[y\9(**  
private String sSiteURL; //Site's URL '%ByFZ zi  
private String sFilePath; //Saved File's Path +1I 7K|M  
private String sFileName; //Saved File's Name "Bv V89  
private int nSplitter; //Count of Splited Downloading File :IU<AG6  
Z t4q= Lr  
Buso `G  
public SiteInfoBean() \crh`~?>  
{//nSplitter的缺省值为5 j\wZjc-j  
//default value of nSplitter is 5 p0y|pD  
this("","","",5); $tF\7.e@  
} ~3-"1E>Rgy  
RX%)@e/@  
nGwon8&]]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) U.V/JbXX  
{ *P5\T4!+d  
sSiteURL= sURL; O8A(OfX  
sFilePath = sPath; (, ik:j  
sFileName = sName; +=Q:g,kP  
this.nSplitter = nSpiltter; -+u}u=z%  
,;hpqu|  
1JU je  
} r*8a!jm?  
o=#ym4hJ%  
Pwj|]0Y@  
public String getSSiteURL() S(U9Dlyarg  
{ #>HY+ ;  
return sSiteURL; ~ o2Z5,H  
} j/Y]3RSMp  
WVsj  
=L@CZ"  
public void setSSiteURL(String value) E24SD'|)  
{ U}4I29M  
sSiteURL = value; WUjRnzVM  
} }Xk_ xQVt{  
(,t[`z  
tBfmjxv  
public String getSFilePath() "g)bNgGV}  
{ ',!jYh}Uxk  
return sFilePath; OiXO<1'$  
} .gGO+8[N*  
mn=b&{')e  
oH&@F@r:+  
public void setSFilePath(String value) eub}+~_?[  
{ [mQ1r*[j  
sFilePath = value; aeI0;u  
} \2=I//YF  
m&b1H9ymd  
0:n"A,-p  
public String getSFileName() "f<gZsb  
{ R2?s NlF  
return sFileName; )iiaT~ ]  
} 5M~+F"Hl  
,?Ie!r$6  
l5=ih9u  
public void setSFileName(String value) wkPjMmW+!  
{ ItvcN  
sFileName = value; yH]Q;X '  
} K!qOO  
]" e'z  
JIw?]xa*  
public int getNSplitter() MRXw)NAw  
{ >q&5Z   
return nSplitter; ^n<YO=|u  
} U^|T{g+O  
U}DE9e{/!  
%FM26^  
public void setNSplitter(int nCount) fMUh\u3  
{ #"~\/sb   
nSplitter = nCount; G u_\ySV/y  
} &*'^uCna  
} P7zUf  
6M`gy|"(~  
)eT>[['fm  
/* ?H,f|nc  
**Utility.java vf@j d}?  
*/ 1$.svR  
package NetFox; ;+(_stxqV9  
&4KUXn[F  
64#Ri!RR}  
public class Utility { 1kpw*$P0  
Nu?A>Q  
[e ztu9  
public Utility() ,wM}h  
{ |a"]@W$>  
.)+c01  
.tGz,z}  
} vV$t`PEY  
LQr!0p.i"  
//线程睡眠 RCYv2=m>Q  
public static void sleep(int nSecond) 6nE/8m  
{ ?D2a"a$^  
try{ <XG]aYBR  
Thread.sleep(nSecond); 9 Xl#$d5  
} 6{^\7`  
catch(Exception e) +D4m@O  
{ CmbgEGIh[a  
e.printStackTrace (); Xe_djy'8  
} QwpX3 k6  
} 'h0>]A 2|X  
:<B_V<  
//日志 $z*"@  
public static void log(String sMsg) axt;}8  
{ ]S]W|m7=.Z  
System.err.println(sMsg); 8rS;}Bt  
} e(a,nZF.  
2]9 2J  
|n tWMm:(  
public static void log(int sMsg) ^7? WR?!  
{ _V1:'T8  
System.err.println(sMsg); $\vNST E  
} ,{S $&g*  
} "ldd&><  
%Rf9 KQ  
60{DR >S  
/* cf$ hIB)Oi  
**TestMethod.java /3rNX}tOMH  
*/ 1Dc6v57  
package NetFox; KMkD6g  
RD)Vb$.B:  
u0arJU_.)  
public class TestMethod { CUG"2K9  
/bo=,%wJ[  
b\H&E{Gn|x  
public TestMethod() (M1YOK)I  
{ ///xx/weblogic60b2_win.exe <F&XT@  
try{ *A8*FX>\F  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 6@/k|t>OT  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7- LjBlH  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i~v[3e9y7  
fileFetch.start(); WHv6E!^\_  
} xrBM`Bj0@  
catch(Exception e){e.printStackTrace ();} bcy  
%5zIh[!1$  
@w.DN)GPo  
} L>1y[ Q  
XI[n!)3  
/1{:uh$  
public static void main(String[] args) )h 6w@TF  
{ ?.F^Oi6 u  
new TestMethod(); uQn1kI[y  
} n!~ $Z/  
} 8]vut{  
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