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http断点续传简单实现(java)

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/* +)zOer,  
**SiteFileFetch.java sf&]u;^DY  
*/ Zo1,1O  
package NetFox; ]Q]W5WDe:  
import java.io.*; f&v9Q97=  
import java.net.*; *5w{8  
qC F5~;7  
[Nn`l,  
public class SiteFileFetch extends Thread { X7k.zlH7T  
iq( )8nxi  
y.KO :P?5{  
SiteInfoBean siteInfoBean = null; //文件信息Bean )95f*wte  
long[] nStartPos; //开始位置 Y0eE-5F,  
long[] nEndPos; //结束位置 4pw6bK,s2\  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7{&|;U  
long nFileLength; //文件长度 cGjPxG;  
boolean bFirst = true; //是否第一次取文件 \&U>LwZd?  
boolean bStop = false; //停止标志 dOa%9[  
File tmpFile; //文件下载的临时信息  : ]C~gc  
DataOutputStream output; //输出到文件的输出流 tcxcup%  
>EY3/Go>  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) D!7`CH+  
public SiteFileFetch(SiteInfoBean bean) throws IOException A}eOFu`  
{ *_>Lmm.yh  
siteInfoBean = bean; >/|q:b^2r  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d!eYqM7-G  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); $DG?M6   
if(tmpFile.exists ()) ~69&6C1Ch  
{ |sJSN.8  
bFirst = false; &b:1I 7Cp*  
read_nPos(); \rv<$d@L  
} H;RwO@v  
else {<<U^<6}  
{ 1GzAG;UUo6  
nStartPos = new long[bean.getNSplitter()]; 6}r`/?"A1  
nEndPos = new long[bean.getNSplitter()]; *}P~P$q%  
} m*JaXa  
Hh+ 2mkg  
AK@9?_D  
oq}'}`lw"  
} !qG7V:6  
Y]&j,j&  
HTG%t/S  
public void run() ~3<> 3p  
{ p, #o<W  
//获得文件长度 4EY)!?;  
//分割文件 h $2</J"  
//实例FileSplitterFetch I_]^ .o1q  
//启动FileSplitterFetch线程 F w?[lS  
//等待子线程返回 `nu''B H  
try{ s0vDHkf8  
if(bFirst) wb0L.'jyR)  
{ z<Nfm  
nFileLength = getFileSize(); 7 qS""f7  
if(nFileLength == -1) =i[\-  
{ a |X a3E  
System.err.println("File Length is not known!"); /'/Xvm3  
} 5 sX+~Q  
else if(nFileLength == -2) X(NLtO w  
{ \kZ?  
System.err.println("File is not access!"); RCpR3iC2  
} ]9^sa-8  
else \.-bZ$  
{ 2Wdyxj Q  
for(int i=0;i<nStartPos.length;i++) 7<*yS310  
{ [@.!~E)P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ~A\GT$  
} ZP(f3X@  
for(int i=0;i<nEndPos.length-1;i++) HAa; hb  
{ u ,KD4{!  
nEndPos = nStartPos[i+1]; A*\.NTM  
} 5?x>9C a  
nEndPos[nEndPos.length-1] = nFileLength; ,5h)x"s  
} iUN Ib  
} aht[4(XH5  
cz8T  
NPp;78O0[  
//启动子线程 'd9INz.  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8]9%*2"!  
for(int i=0;i<nStartPos.length;i++) ;>Ib^ov  
{ gDpVeBd[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 4\iOeZRf  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H*PSR  
nStartPos,nEndPos,i); %iQD /iT5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %WjXg:R  
fileSplitterFetch.start(); [D I+~F  
} J| w>a  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ds<2I,t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |IzPgC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 8<QdMkI  
nEndPos = " + nFileLength); <eWf<  
// fileSplitterFetch[nPos.length-1].start(); bKMy|_  
m+]K;}.}R  
Fj2BnM3#  
//等待子线程结束 , s"^kFl  
//int count = 0; s;ls qQk  
//是否结束while循环 H&-zZc4\  
boolean breakWhile = false; X}Ai -D  
[M=7M}f;  
QTk}h_<u  
while(!bStop) m;GCc8  
{ _l8 9  
write_nPos(); +V{kb<P  
Utility.sleep(500); *XIF)Q=<>  
breakWhile = true; i9,ge Q7d  
4O^xY 6m  
1~NT.tY  
for(int i=0;i<nStartPos.length;i++) n{ar gI8wF  
{ k_rt&}e+Gi  
if(!fileSplitterFetch.bDownOver) Swig;`  
{ -cAo@}v  
breakWhile = false; tEvut=k'  
break; *0Skd  
} iP ->S\  
} .WZ^5>M-  
if(breakWhile) Ga^"1TZ x  
break; #lL^?|M  
KJ)k =mJ  
8V`WO6*  
//count++; W}@c|d $`  
//if(count>4) #A JDWelD  
// siteStop(); -=)H{  
} y51e%n$  
s<<ooycBrQ  
1#< '&Lr  
System.err.println("文件下载结束!"); ^@s1Z7  
} $ r@zs'N  
catch(Exception e){e.printStackTrace ();} E Nh l&J  
} f@wquG'  
B" 1c  
|4;Fd9q^m  
//获得文件长度 1Y\DJ@lh  
public long getFileSize() wDal5GJp  
{ `ts$(u.w  
int nFileLength = -1; PR#exm&  
try{ FrfM3x6UM  
URL url = new URL(siteInfoBean.getSSiteURL()); |6sp/38#p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); >* f-Wde  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5H<m$K4z  
[ )Iv^ U9  
'}53f2%gKa  
int responseCode=httpConnection.getResponseCode(); ;PF<y9M  
if(responseCode>=400) )l C)@H}  
{ %S960  
processErrorCode(responseCode); P^ ~yzI  
return -2; //-2 represent access is error & p  
} 99e.n0  
g[' ^L +hd  
WUn]F~Lt  
String sHeader; u5`u>.!  
EIP /V  
xX&+WR  
for(int i=1;;i++) fgp]x&5Q  
{ l`lk-nb  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); cJ= 6r :  
//Utility.log(in.readLine()); q_[o" wq/  
sHeader=httpConnection.getHeaderFieldKey(i); MS~(D.@ZS  
if(sHeader!=null) #4 <SAgq  
{ *SJ_z(CZm  
if(sHeader.equals("Content-Length")) tKOmoC  
{ zZPO&akB"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {H>gtpVy  
break; @1roe G  
} ,wb:dj-  
} {BN#h[#B{  
else t\dN DS  
break; #jvtUS\  
} yLvDMPj  
} EeE7#$l  
catch(IOException e){e.printStackTrace ();} `KoV_2|  
catch(Exception e){e.printStackTrace ();} zFfr. g;L  
VPJElRSH  
BA:VPTZq  
Utility.log(nFileLength); y%cP1y)  
R`qFg/S  
2*& ^v  
return nFileLength; ,]F,Uu_H7  
} W aRw05r  
W' VslZG  
tCH!my_  
//保存下载信息(文件指针位置) 3qC}0CP*  
private void write_nPos() AO4U}?  
{ 1v2 7;Q<+Q  
try{ Ty?cC**  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Tx# Mn~xD  
output.writeInt(nStartPos.length); D%pF;XY  
for(int i=0;i<nStartPos.length;i++) (mpNcOY<D  
{ %$Tji  
// output.writeLong(nPos); eu-*?]&Di  
output.writeLong(fileSplitterFetch.nStartPos); pz}.9 yI8  
output.writeLong(fileSplitterFetch.nEndPos); Se}c[|8  
} e#8Q L  
output.close(); H/ HMm{4  
} A|4[vz9>H  
catch(IOException e){e.printStackTrace ();} A}9`S6@@  
catch(Exception e){e.printStackTrace ();} v@L;x [Q  
} K($Npuu]  
$7ZX]%<s  
$qnZl'O>  
//读取保存的下载信息(文件指针位置) QA`sx  
private void read_nPos() Q Z  
{ B~ GbF*j  
try{ Wqw1J=]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); %ntRG !  
int nCount = input.readInt(); D/&o& G96  
nStartPos = new long[nCount]; kgP0x-Ap  
nEndPos = new long[nCount]; e X|m  
for(int i=0;i<nStartPos.length;i++) AQvudx)@"  
{ ]h+j)J}[A  
nStartPos = input.readLong(); +I|vzz`ZVr  
nEndPos = input.readLong(); V b?oJhR  
} 14yv$,  
input.close(); ^6V[=!& H  
} 8Fu(Ft^9  
catch(IOException e){e.printStackTrace ();} ea 'D td  
catch(Exception e){e.printStackTrace ();} SY\ gXO8k  
} f.$af4 u  
+a+Om73B2  
'-~~-}= sJ  
private void processErrorCode(int nErrorCode) l'_r:b  
{ @qAS*3j  
System.err.println("Error Code : " + nErrorCode); fIU#M]Xx  
} VY4yS*y  
sDlO#  
K w ]=  
//停止文件下载 sUQ@7sTj  
public void siteStop() %dVZ0dl  
{ VpDbHAg  
bStop = true; <PH #[dH  
for(int i=0;i<nStartPos.length;i++) 5U$0F$BBp  
fileSplitterFetch.splitterStop(); + [mk<pQ  
m;QMQeGz  
Kn1a>fLaJ_  
} !Wnb|=j  
} oZ|\vA%4^  
//负责部分文件的抓取 !%c\N8<>GD  
**FileSplitterFetch.java <0!):zraS  
*/ %>{0yEC  
package NetFox; ^<2p~h0 \  
h S&R(m  
/a4{?? #e  
import java.io.*; 64tvP^kp  
import java.net.*; M .mfw#*  
D'Q\za  
@\#td5'  
public class FileSplitterFetch extends Thread { 83#mB:^R  
zK@@p+n_#.  
eng'X-x  
String sURL; //File URL jNk%OrP]  
long nStartPos; //File Snippet Start Position i8]S:49  
long nEndPos; //File Snippet End Position MQ8J<A Pf-  
int nThreadID; //Thread's ID |CRn c:  
boolean bDownOver = false; //Downing is over *$g-:ILRuZ  
boolean bStop = false; //Stop identical Y$@?.)tY  
FileAccessI fileAccessI = null; //File Access interface "4{r6[dn  
wf<M)Rs|  
.?$gpM?i  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 4.t-i5  
{ DB,J3bm  
this.sURL = sURL; cbTm'}R(G  
this.nStartPos = nStart; PdWx|y{%  
this.nEndPos = nEnd; .$vK&k  
nThreadID = id; jse&DQ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 PEZ!n.'S  
} C,4e"yynb  
4o[{>gW  
Nj/ x. X  
public void run() xJ.M;SF4  
{ nU7[c| =  
while(nStartPos < nEndPos && !bStop) O:K2Y5R?B  
{ 0o&5 ]lEe  
^iV)MTT  
Zj'9rXhrM1  
try{ j0q&&9/Jj  
URL url = new URL(sURL); vnuN6M{  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); & 1f+,  
httpConnection.setRequestProperty("User-Agent","NetFox"); Lr pM\}t  
String sProperty = "bytes="+nStartPos+"-"; 2D5StCF$O  
httpConnection.setRequestProperty("RANGE",sProperty); |`FY1NN   
Utility.log(sProperty); 'LDQgC*%  
rYk0 ak  
;!Fn1|)  
InputStream input = httpConnection.getInputStream(); p5*EA x  
//logResponseHead(httpConnection); x]j W<A  
4CTi]E=H{  
6_B]MN!(  
byte[] b = new byte[1024]; $%f&a3#  
int nRead; I7 ]8Y=xf  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) gs`q6 f%(  
{ .T`%tJ-Em  
nStartPos += fileAccessI.write(b,0,nRead); <1TAw.  
//if(nThreadID == 1) &UFZS94@r  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); M<&= S  
} (/$^uWj  
}x ,S%M-  
xoME9u0x4  
Utility.log("Thread " + nThreadID + " is over!"); Q+{n-? :  
bDownOver = true; .e-#yET  
//nPos = fileAccessI.write (b,0,nRead); 'Pbr v  
} 8eRLy/`gd  
catch(Exception e){e.printStackTrace ();} Q,Eo mt  
} BTxrp  
} m]&SNz=  
3XNCAb2  
N2o7%gJw  
//打印回应的头信息 &7s.`  
public void logResponseHead(HttpURLConnection con) @2#lI  
{ R.3q0yZ wF  
for(int i=1;;i++) -nwypu  
{ qe\5m.k  
String header=con.getHeaderFieldKey(i); A@u@ift  
if(header!=null) 7xR\kL.,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cZ3v=ke^  
Utility.log(header+" : "+con.getHeaderField(header)); J .<F"r>  
else B)UZ`?>c  
break; \b>] 8Un"  
} J[kTlHMD  
} 1Z&(6cDY8M  
XK vi=0B  
wuo,kM  
public void splitterStop() 7j{?aza  
{ =EsavN  
bStop = true; Uw:"n]G]D?  
} l+b~KU7~l  
}QmqoCAE~m  
GA.8@3  
} z(~_AN M4,  
& 5R&k0i r  
K)P%;X  
/* Tj- s4x  
**FileAccess.java Alq(QDs  
*//文件访问(定位,写) C_Wc5{  
package NetFox; D m9sL!  
import java.io.*; y)<q /  
(tO\)aS=  
phz&zl D  
public class FileAccessI implements Serializable{ Tsx>&WC  
4&iCht =  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 qJw_  
RandomAccessFile oSavedFile; *K; ~!P  
long nPos; o !7va"  
Ea=P2:3*  
6MI8zRX  
public FileAccessI() throws IOException Bbp|!+KP{(  
{ ##ANrG l  
this("",0); @%SQFu@FJ  
} D&zle~" J  
T^q 0'#/  
wKHBAW[i]  
public FileAccessI(String sName,long nPos) throws IOException 3 gf1ownC  
{ zW nR6*\  
oSavedFile = new RandomAccessFile(sName,"rw"); ?h2}#wg  
this.nPos = nPos; 'B}qZCy W  
oSavedFile.seek(nPos); WF"k[2  
} _vZOZKS+  
,u!sjx  
y+;|Fz  
public synchronized int write(byte[] b,int nStart,int nLen) [ /ZO q  
{ 2T`!v  
int n = -1; 3uMy]HUQ  
try{ dqAw5[qMJ  
oSavedFile.write(b,nStart,nLen); l;V173W=&  
n = nLen; o"SMbj  
} H)&R=s  
catch(IOException e) jh$='Gn  
{ 92-I~ !d  
e.printStackTrace (); rLT!To  
} h7@6T+#WoT  
A)~6Im  
QCJM&  
return n; xLn%hxm?,  
} (iGTACoF  
$ulOp;~A%  
y?!"6t7&  
} ET >](l9  
=Runf +}  
U ;I9 bK8  
/* {:W$LWET  
**SiteInfoBean.java SY8C4vb'h  
*/ 8EEuv-aeo  
package NetFox; uVU)d1N  
lRdChoL$2  
~_ a-E  
public class SiteInfoBean { F&Hrk|a  
J-4:H gx  
@lt#Nz  
private String sSiteURL; //Site's URL ?hM64jI|  
private String sFilePath; //Saved File's Path Sx\]!B@DSu  
private String sFileName; //Saved File's Name Np)lIGE  
private int nSplitter; //Count of Splited Downloading File L4f3X~8,b  
+^<](z  
c"xK`%e  
public SiteInfoBean() 9{uO1O\  
{//nSplitter的缺省值为5 ;=UsAB]  
//default value of nSplitter is 5 S@sO;-^+  
this("","","",5); A(0lM`X  
} WN<zkM~3  
39jG8zr=Z[  
R FH0  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) M@ZI\  
{ |WUG}G")*x  
sSiteURL= sURL; ]:\dPw`A  
sFilePath = sPath; ?'je)F  
sFileName = sName; hpJ-r  
this.nSplitter = nSpiltter; a'z7(8$$  
Q5_o/wk  
C8\^#5  
} Y4(  
;UP$yM;  
snikn&  
public String getSSiteURL()  7[wieYj{  
{ ctJE+1#PH  
return sSiteURL; 3yXY.>'  
} qjc4.,/  
 f V(J|  
IqGdfL6[(  
public void setSSiteURL(String value) A+)`ZTuO  
{ cFWc<55aX6  
sSiteURL = value; V470C@  
} ?R#)1{(8d~  
\^%}M!tan  
u~-8d;+?y  
public String getSFilePath() !Rt>xD  
{ V2G6Kw9gt  
return sFilePath; ?pZOeqqu$  
} &! ?eL  
` ~`k_7t.  
IaXeRq?<  
public void setSFilePath(String value) N.{D$"  
{ = 9]~ yt  
sFilePath = value; yvYad  
} K96<M);:g  
r>U@3%0&  
m9Hit8f@Q  
public String getSFileName() C2Tyoza  
{ xZv#Es%#  
return sFileName; puM3g|n@  
} t<viX's  
}Z,x~G  
!GGkdg*-*9  
public void setSFileName(String value) &JI8]JmU)  
{ W{gb:^;zb  
sFileName = value; uR r o?m<  
} ^`>/.gL  
$p?aVO  
J9[r|`gJ(  
public int getNSplitter() d<N:[Y\4l  
{ \K!VNB>h  
return nSplitter; ( ICd}  
} xUistwq  
(*)hD(C5  
9p2&) kb6  
public void setNSplitter(int nCount) %1$,Vs<RH  
{ tC9n k5~  
nSplitter = nCount; q%?in+l  
} %-0t?/>  
} )%@J=&G8TT  
Hg$lXtn]  
)TH@# 1  
/* #?9;uy<j.q  
**Utility.java v oj^pzZ  
*/ Tyf`j,=  
package NetFox; >s?S+W[L  
 'CkIz"Wd  
=>af@C.2  
public class Utility { MFAH%Z$  
';=O 0)u  
=$Nq   
public Utility() b`O'1r\Y;  
{ e&aWq@D  
;x@~A^<el  
s6^>F/x  
} W]5w \  
b?QoS|<e?  
//线程睡眠 _8_R 1s  
public static void sleep(int nSecond) hNmJ!Uo  
{ (c &mCJN  
try{ FE|JHh$  
Thread.sleep(nSecond); VZmLS 4E  
} h|{]B,.Lh  
catch(Exception e) T <ET )D7  
{ o="M  
e.printStackTrace (); !NvI:C_4|  
} Y^EcQzLw  
} 4 VW[E1<  
SmSH2m-  
//日志 y ~!Zg}o  
public static void log(String sMsg) Q:k}Jl  
{ FZslv"F  
System.err.println(sMsg); <s<n  
} iVq'r4S  
f5VLw`m}.8  
^N{h3b8  
public static void log(int sMsg) R3&Iu=g  
{ G^4hd i3@  
System.err.println(sMsg); zL`iK"N`  
} T&u5ki4NE  
} Lhb35;\  
"8jf81V*  
41?HY{&2  
/* UIN<2F_  
**TestMethod.java P%&0]FCx  
*/ G.a bql  
package NetFox; CxOob1@  
Jgd'1'FOs  
c>:wd@w  
public class TestMethod { ARwD~ Tr  
a>I+]`g  
ryUQU^v  
public TestMethod() Z!zF\<r  
{ ///xx/weblogic60b2_win.exe EF}\brD1  
try{ cZU=o\  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); '3D XPR^B6  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ;1O_M9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >T3-  
fileFetch.start(); MSqVlj  
} /,&<6c-Q@W  
catch(Exception e){e.printStackTrace ();} ,|H `e^  
/quc}"__  
e+ BQww  
} H-*yh!  
 zC@o  
?u=Fj_N_  
public static void main(String[] args) {xB!EQ"  
{ as4;:  
new TestMethod(); suiS&$-E  
} A,hJIe  
} QIvVcfM^  
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