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http断点续传简单实现(java)

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/* [|eIax xR,  
**SiteFileFetch.java ?zutU w/m  
*/ *v K~t|z  
package NetFox; a BMV6'  
import java.io.*; S$fS|N3]%  
import java.net.*; e4Y+u8gT  
=UK:83R(  
E2w-b^,5  
public class SiteFileFetch extends Thread { '*rS, y  
K g#Bg##  
Tb?XKO,  
SiteInfoBean siteInfoBean = null; //文件信息Bean _$@fCo0  
long[] nStartPos; //开始位置 KNQj U-A  
long[] nEndPos; //结束位置 Y_ne?/sZE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 U9b[t  
long nFileLength; //文件长度 exiu;\+j  
boolean bFirst = true; //是否第一次取文件 cRr3!<EZ  
boolean bStop = false; //停止标志 ;r"r1'a+@  
File tmpFile; //文件下载的临时信息 %gFIu.c  
DataOutputStream output; //输出到文件的输出流 ((`{-y\K  
e#h&Xa  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) P (7el  
public SiteFileFetch(SiteInfoBean bean) throws IOException JB'tc!!*  
{ Ji!i}UjD7!  
siteInfoBean = bean; 9H4"=!AAgD  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); i>h 3UIx\  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); O^-QqCZE  
if(tmpFile.exists ()) gTTKjlI [  
{ R,PN?aj  
bFirst = false; 3-:^mRPJ  
read_nPos(); t/O^7)%  
} 3T]cDVQ_  
else We}9'X}  
{ PP'5ANK  
nStartPos = new long[bean.getNSplitter()]; ,=Wj*S)~  
nEndPos = new long[bean.getNSplitter()]; H'YKj'  
} Zh;}Q(w  
z$%8'  
D60quEe3%  
Eb9h9sjv  
} i{$P.i/&  
H9TeMY  
8i73iTg(  
public void run() Z9 ws{8@_  
{ w)vpo/?  
//获得文件长度 v mkiw1  
//分割文件 )#\3c,<Y  
//实例FileSplitterFetch Z.@n7G  
//启动FileSplitterFetch线程 LXby(|< j  
//等待子线程返回 <#M1I!R  
try{ Y&=DjKoVh  
if(bFirst) R||$Rfe  
{ M61Nl)|mx&  
nFileLength = getFileSize(); lc5(^ ~  
if(nFileLength == -1) oP56f"BE(  
{ !L9|iC:8  
System.err.println("File Length is not known!"); ^vG<Ma.yk  
} C7m/<  
else if(nFileLength == -2) v ,h"u  
{ `&fW<5-  
System.err.println("File is not access!"); =d5;F`m  
} >T [Y>]  
else !F}GSDDV*  
{ ?F[_5ls|]  
for(int i=0;i<nStartPos.length;i++) h+H+>,N8`  
{ 6%6dzZ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); X!z-J>  
} pwHe&7e#  
for(int i=0;i<nEndPos.length-1;i++) 4>L* 7i  
{ #M w70@6  
nEndPos = nStartPos[i+1]; x{w|Hy  
} ) aMiT  
nEndPos[nEndPos.length-1] = nFileLength; {RI^zNgs[  
} -;"A\2_y  
} N@<-R<s^  
z0ufLxq  
Il@K8?H@  
//启动子线程 x@oxIXN  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7#UJ444b~  
for(int i=0;i<nStartPos.length;i++) C "@>NC_  
{ RZpjr !R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), xE--)=<$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), KV;q}EyG  
nStartPos,nEndPos,i); _IU5HT}2  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6j {ynt  
fileSplitterFetch.start(); 85|u;Fxf  
} K-Pcew^?  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1qn/*9W}=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); R1Rk00Ow:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", _/P;`@  
nEndPos = " + nFileLength); "\;n t5L  
// fileSplitterFetch[nPos.length-1].start(); =m (u=|N3  
0k\,z(e  
kP('X/  
//等待子线程结束 M+ <SSi"  
//int count = 0; `:r-&QdU o  
//是否结束while循环 .e3@fq  
boolean breakWhile = false; '*`n"cC:  
.,S`VNU  
j&S.k  
while(!bStop) 16I[z+RG  
{ yG~Vvpv  
write_nPos(); X[<#B5  
Utility.sleep(500); J#@+1 Nt  
breakWhile = true; 8#A4B2  
\A\?7#9\  
d<OdQvW.  
for(int i=0;i<nStartPos.length;i++) qu $FpOJ  
{ aG =6(ec.  
if(!fileSplitterFetch.bDownOver) "Zn nb*pOM  
{ .%W.uF^  
breakWhile = false; 45%D^~2~F  
break; M"K$.m@t  
} d<=!*#q;o  
} /03 Wst  
if(breakWhile) DU*qhW`X  
break; PK&&Vu2M  
yF|yZ{  
2'W# x  
//count++; q%A>q ;l:  
//if(count>4) UL~~J[1r  
// siteStop(); HXdo:#xEO  
} tNZZCdB  
<Mo{o2F=  
UHfE.mTjM  
System.err.println("文件下载结束!"); G;/> N'#  
} +[ir7?Y.  
catch(Exception e){e.printStackTrace ();} l>i:M#z&  
} 8?<J,zu@AV  
&dw=jHt  
c@]G;>o  
//获得文件长度 ca0vN^Ji  
public long getFileSize() ^a3 (QKS  
{ r_bG+iw7p  
int nFileLength = -1; 7bGt'gvv  
try{ bqF?!t<B  
URL url = new URL(siteInfoBean.getSSiteURL()); 4C:dkaDq]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); OOnj(%g  
httpConnection.setRequestProperty("User-Agent","NetFox"); t^6ams$  
cyjgi /Z  
# E8?2]  
int responseCode=httpConnection.getResponseCode(); +W-b3R:1>  
if(responseCode>=400) Ty!V)i  
{ J- l[dC  
processErrorCode(responseCode); 2.{<C.BK{  
return -2; //-2 represent access is error P$ b5o  
} fyx Q{J  
NX;{L#lQ  
BjjuZN&  
String sHeader; w}07u5  
Ut1s~b1  
}p)a 7xn}  
for(int i=1;;i++) yVPFH~1@\  
{ Bv*VNfUm  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %%wngiz\  
//Utility.log(in.readLine()); nddCp~NX  
sHeader=httpConnection.getHeaderFieldKey(i); e cvZwL  
if(sHeader!=null) 9/&1lFKJ  
{ 0f+]I=1\  
if(sHeader.equals("Content-Length")) 0U.Ld:  
{ @JP6F[d  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); #=m:>Q?%z  
break; %A&g-4(  
} NLgeBLB  
} > -fXn  
else lY |]  
break; Mcd K!V  
} ]8cD,NS  
} F?y C=  
catch(IOException e){e.printStackTrace ();} r|3u]rt  
catch(Exception e){e.printStackTrace ();} ZiH4s|  
bhZ5-wo4%  
DAMw(  
Utility.log(nFileLength); geqx":gpx9  
`I|Y7GoUO  
cIuCuh0I`  
return nFileLength; * _,yK-et  
} dftX$TS  
73nmDZO|  
6p,}?6^  
//保存下载信息(文件指针位置) ~ :B/`1[m  
private void write_nPos() 0R&7vn  
{ 3`"k1W  
try{ ]<fZW"W< q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); }4Gn$'e  
output.writeInt(nStartPos.length); R3BK\kf&  
for(int i=0;i<nStartPos.length;i++) hH?ke(&=f  
{ ) I.uqG  
// output.writeLong(nPos); -fK_F6_\]  
output.writeLong(fileSplitterFetch.nStartPos); diw5h};W  
output.writeLong(fileSplitterFetch.nEndPos);  GL&rT&  
} p1ER<_fp  
output.close(); kY~yA2*G  
} L{c\7  
catch(IOException e){e.printStackTrace ();} TjctK [db@  
catch(Exception e){e.printStackTrace ();} KZ [:o,jp>  
} }L5;=A']S  
MF::At[4   
k@9q5lu;T  
//读取保存的下载信息(文件指针位置) 2+LvlS)C  
private void read_nPos() U4e9[=q`'  
{ z-S8s2.Fd  
try{ 7H[.o~\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 6SSrkj}U  
int nCount = input.readInt(); # kmI#W"^  
nStartPos = new long[nCount]; 6<n+p'+n  
nEndPos = new long[nCount]; ia-&?  
for(int i=0;i<nStartPos.length;i++) DsiyN:o'+  
{ lWU? R  
nStartPos = input.readLong(); &G+:t)|S  
nEndPos = input.readLong(); 2|+4xqNJm  
} kr]_?B(r  
input.close(); 3SOrM  
} .noY[P 8i  
catch(IOException e){e.printStackTrace ();} )q%DRLD'G  
catch(Exception e){e.printStackTrace ();} 9Bu=8P?  
} UWBR5  
) .H nK  
a'\fS7aE0l  
private void processErrorCode(int nErrorCode) 8 A#\V  
{ .lppT)P  
System.err.println("Error Code : " + nErrorCode); ! AL?bW  
} ]G=^7O]`C!  
A^ry|4`3(  
B|BJkY'  
//停止文件下载 MCfDR#a  
public void siteStop() N8]d0  
{ Y{m1\s/o  
bStop = true; r P&.`m88n  
for(int i=0;i<nStartPos.length;i++) N5fMMi(O  
fileSplitterFetch.splitterStop(); (Yc}V  
`q1K%id  
mY]R~:  
} DzvGR)>/  
} n11eJEtm  
//负责部分文件的抓取 9uY$@7qH  
**FileSplitterFetch.java 2` h  
*/ %XWb|-=  
package NetFox; zeHs5P8}r  
XE*#5u8t  
sX=_|<[  
import java.io.*; lem\P_V)  
import java.net.*; WAh{*$Rpl  
*s"{JrG`O  
"V7&@3  
public class FileSplitterFetch extends Thread { as@I0e((  
?s{Pp  
5A"OL6ty  
String sURL; //File URL ~FZ=  
long nStartPos; //File Snippet Start Position '\Hh  
long nEndPos; //File Snippet End Position l,M?   
int nThreadID; //Thread's ID kR(hUc1O  
boolean bDownOver = false; //Downing is over Y !nE65  
boolean bStop = false; //Stop identical KZTT2KsYl  
FileAccessI fileAccessI = null; //File Access interface SNf*2~uq)  
x-s]3'!L  
Y-:{a1/RKo  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException sBu- \P#  
{ A! !W\Jt  
this.sURL = sURL; yi3Cd@t({{  
this.nStartPos = nStart; h{M.+I$}C  
this.nEndPos = nEnd; e? !A]2  
nThreadID = id; 9.$k^|~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 1'[_J  
} tdB<  
. [\S=K|/  
GbZqLZ0  
public void run() pWXoJ0N  
{ *H%Jgz,  
while(nStartPos < nEndPos && !bStop) C)`y<O  
{ elm]e2)F  
+}0/ %5 =1  
D[ (A`!)  
try{ a-7T   
URL url = new URL(sURL); JN-wToOF  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }zu?SZH  
httpConnection.setRequestProperty("User-Agent","NetFox"); 72>/@  
String sProperty = "bytes="+nStartPos+"-"; 3]}wZY0  
httpConnection.setRequestProperty("RANGE",sProperty); } ^67HtNQ  
Utility.log(sProperty); Vi1= E])  
o72G oUfs  
\"@BZ.y  
InputStream input = httpConnection.getInputStream(); ril4*$e7^\  
//logResponseHead(httpConnection); !r*Ogv[  
\sZ!F&a~  
ACcxQK}  
byte[] b = new byte[1024]; V/}g'_E  
int nRead; z<c@<M=Q*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) fB3W} dr  
{ !4B($]t  
nStartPos += fileAccessI.write(b,0,nRead); !B &%!06  
//if(nThreadID == 1) B'Ll\<mq@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); + \AiUY  
} }?jL;CCe  
@NS=  
kG>d^K  
Utility.log("Thread " + nThreadID + " is over!"); ^ LT KX`p  
bDownOver = true; \-B8`ah  
//nPos = fileAccessI.write (b,0,nRead); J2W:Q  
} R4Vi*H  
catch(Exception e){e.printStackTrace ();} {m/h3hjFa  
} ]N+(SU  
} A\7qPfpG  
LD~/*  
Eh&et0&=g  
//打印回应的头信息 jKI0d+U  
public void logResponseHead(HttpURLConnection con) 6Tn.56X  
{ ~]_g q;bG  
for(int i=1;;i++) d)&}% 2ku  
{ D> |R.{  
String header=con.getHeaderFieldKey(i); ' s6SKjZS  
if(header!=null) 7C%z 0/  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 4iiW{rh4  
Utility.log(header+" : "+con.getHeaderField(header)); Z;6v`;[  
else <g|\]\C|  
break; 2}P?N  
} L`Lro:E?kL  
} OTNcNY  
1 \_S1ZS  
5P'<X p  
public void splitterStop() ~a^"VQ5]ac  
{ U!rhj&n  
bStop = true; ,s*-2Sz  
} WZ a?Xb  
&xG>"sJ  
wua`e <"  
} dd +%d  
+&7D ;wj=  
"r Bb2.  
/* XUrxnJ4  
**FileAccess.java qMrBTq[  
*//文件访问(定位,写) '7UW\KEB[}  
package NetFox; yrnIQu*Uu  
import java.io.*; %,G&By&,  
$s*\yam?|  
%4/>7 aB]Y  
public class FileAccessI implements Serializable{ Vnu*+  
zYpIG8"o5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Q>7#</i\.  
RandomAccessFile oSavedFile; ac>}$Uw)  
long nPos; D *W+0  
8~RUYsg  
_Ptf^+  
public FileAccessI() throws IOException fC xN!  
{ +5Ir=]=T9  
this("",0); -aG( Yx  
} XOa<R  
Noz+\O\  
j{V xB  
public FileAccessI(String sName,long nPos) throws IOException *7oPM5J|v  
{ 0K>rc1dy  
oSavedFile = new RandomAccessFile(sName,"rw"); RL~|Kr<7J  
this.nPos = nPos; C yC<{D+  
oSavedFile.seek(nPos); g_;5"  
} ~B>I?j  
Z]$yuM  
1j o.d  
public synchronized int write(byte[] b,int nStart,int nLen) O8SX#,3^}  
{ 8"wA8l.  
int n = -1; N rVQK}%K  
try{ N\H{p %8  
oSavedFile.write(b,nStart,nLen); ./kmI#gaV  
n = nLen; v3S{dX<  
} Bx E1Ky8@A  
catch(IOException e) r&}fn"H!  
{ T7m rOp  
e.printStackTrace (); b9EJLD  
} gb@Rx  
W~W^$A  
\ :})R{  
return n; $>/J8iB  
} z-[Jbjhd  
|:!#k A  
tRbZ^5x\@  
} 0J$wX yh  
zQ]IlMt  
)~d2`1zGS  
/* BOL_kp"   
**SiteInfoBean.java a6WE,4T9  
*/ "4g1I<  
package NetFox;  t8GJ;  
dq:M!F  
kGc)Un?'{U  
public class SiteInfoBean { }C" #b\A2  
>ID 3oi  
H/)=  
private String sSiteURL; //Site's URL DX$`\PA  
private String sFilePath; //Saved File's Path [n74&EH  
private String sFileName; //Saved File's Name KN}[N+V>  
private int nSplitter; //Count of Splited Downloading File y H+CyL\  
GmAE!+"  
J)jiI>  
public SiteInfoBean() NPB':r-8  
{//nSplitter的缺省值为5 ^D.B^BR  
//default value of nSplitter is 5 Y%=A>~s*c:  
this("","","",5); uT-WQ/id  
} <V6#)^Or  
gLpWfT29V  
ew`R=<mZ,7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @ K@~4!  
{ <NJ7mR}  
sSiteURL= sURL; N_gjOE`x5  
sFilePath = sPath; nosEo? {  
sFileName = sName; dk(-yv'  
this.nSplitter = nSpiltter; ?: meix  
TfZO0GL$  
|LNXu  
} }kOhwT8sI  
(|6q N  
*=2jteG=3.  
public String getSSiteURL() fA 3  
{ b-O4IDIT  
return sSiteURL; /(}V!0\?  
} "lz!'~im  
O'wN4qb=F  
Q ?Nzt;)!.  
public void setSSiteURL(String value) qp{NRNkQ  
{ J,~)9Kh$  
sSiteURL = value; n]o+KT\  
} 9J|YP}%  
" 3^6  
g{D&|qWj  
public String getSFilePath() n `n3[  
{ "RShsJZMH  
return sFilePath; \JyWKET::_  
} #qn)Nq(  
u>(Q& 25  
A>4k4*aFm#  
public void setSFilePath(String value) L,D!T&B  
{ ebao7r5@  
sFilePath = value; -p;o e}|  
} HOUyB's'  
&U,f~KJ  
2fLd/x~  
public String getSFileName() rxz3Mqg  
{ lGM3?AN  
return sFileName; KC]Jbm{y  
} hZ#tB  
H\b5]q %  
&t8_J3?Z  
public void setSFileName(String value) $yc,D=*Isi  
{ s<dD>SU  
sFileName = value; Z8#I  
} 9D| FqU |  
2$Ji4`p}S  
q+:(@w6  
public int getNSplitter() lt$7 97  
{ i&3 0n#  
return nSplitter; U-? ^B*<  
} g:6yvEu$ -  
m0* B[  
zo5.}mr+  
public void setNSplitter(int nCount) N1Z8I:  
{ N 4v)0  
nSplitter = nCount; X@Bpjg  
} UxvsSHi  
} c@^:tB  
r zmk-V  
6nfkZvn  
/* xh6x B|Z  
**Utility.java _l,Z38  
*/ I>3]4mI*a  
package NetFox; 2%qn !+.  
PHK#b.B>a8  
:fYwFD( 9  
public class Utility { _]S6>  
p)^:~ ll  
`p{ !5  
public Utility() Yz,!#ob$  
{ w.Vynb  
)ra66E  
xI4I1"/  
} D+)=bPMe  
Riw7<j  
//线程睡眠 ],YYFU}  
public static void sleep(int nSecond) -h@0 1  
{ 1a$V{Eag  
try{ DqMK[N,0  
Thread.sleep(nSecond); BXo|CITso  
} Doh|G:P]#  
catch(Exception e) ^!<7#kX  
{ z;C=d(|nN  
e.printStackTrace (); 1 (i>Vt.+  
} W #L"5pRg  
} J=X% xb  
MH.,s@  
//日志 =b!J)]  
public static void log(String sMsg) .G_3blE;  
{ GeaDaYh#T  
System.err.println(sMsg); mrC+J*  
} )6Q0f  
~{vdP=/WP  
gww^?j#  
public static void log(int sMsg) K) `:v|d  
{ ZGpTw[5ql  
System.err.println(sMsg); #a |ch6B  
} 5g1M_8e'+  
} v$m[#&O^V?  
 aoDD&JE  
PGPbpl&\t  
/* o~x39  
**TestMethod.java ;(Xe@OtW  
*/ Yb\\ w<@g  
package NetFox; uUz`=4%A  
+qUkMx  
pTALhj#,  
public class TestMethod { T5azYdzJy  
!wd'::C  
hO/5>Zv?  
public TestMethod() XU_,Z/Yw_  
{ ///xx/weblogic60b2_win.exe #t@x6Vt  
try{ f5aF6FBH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #<wpSs  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); tP`G]BCbt  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !(*a+ur&i  
fileFetch.start(); rMHQzQ0%  
} }xb_s  
catch(Exception e){e.printStackTrace ();} < m enABN4  
OwA~(  
V5O=iMP  
} )[^y t0%  
;tp]^iB#  
m-ph}  
public static void main(String[] args) nuSN)}b<Q  
{ JOrELrMx  
new TestMethod(); #Pu@Wx  
} rX33s  
} F#1 Kk#t  
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