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http断点续传简单实现(java)

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/* W+=j@JY}q9  
**SiteFileFetch.java B:UPSX)A  
*/ %uV,p!| )  
package NetFox; # c1LOz  
import java.io.*; 5Rw2/J L  
import java.net.*; 3_boEYl0  
>d"\  
mC\<fo-u  
public class SiteFileFetch extends Thread { ?6ssSjR}  
;w]1H&mc*A  
VSCKWYy  
SiteInfoBean siteInfoBean = null; //文件信息Bean bJ"2|VNH(  
long[] nStartPos; //开始位置 lf KV%  
long[] nEndPos; //结束位置 XVfUr\=,T  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 9 ;uw3vI%  
long nFileLength; //文件长度 "%dENK  
boolean bFirst = true; //是否第一次取文件 @gf <%>  
boolean bStop = false; //停止标志 =MM+(mD  
File tmpFile; //文件下载的临时信息 ~Eik&5 z  
DataOutputStream output; //输出到文件的输出流 5eF tcK  
S5F5Tr;TN  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) {2 T:4i5  
public SiteFileFetch(SiteInfoBean bean) throws IOException F=*t]X[z}  
{ \Wppl,"6c  
siteInfoBean = bean; <jYyA]Zy5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Pj g#  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); IN#/~[W  
if(tmpFile.exists ()) QqW N7y_9  
{ U1/ww-!Z  
bFirst = false; CK4#ZOiaa  
read_nPos(); ]goV Q'Y  
} 8p}z~\J{a:  
else =s'H o  
{ {|<r7K1<  
nStartPos = new long[bean.getNSplitter()]; 7.2!g}E  
nEndPos = new long[bean.getNSplitter()]; "7Kw]8mRR  
} &"T7KXx  
\SwqBw  
YKayaI\*  
o.|36#Fa  
} o>d0R w4h  
b%@9j;  
N.E{6_{S  
public void run() MZA%ET,l,<  
{ Y:Lkh>S1Q  
//获得文件长度 *>W6,F7  
//分割文件 H>]*<2(=-  
//实例FileSplitterFetch x N>\t& c  
//启动FileSplitterFetch线程 n4XkhY|  
//等待子线程返回 Nknd8>Hy+  
try{ Kc1w[EQ  
if(bFirst) fo/sA9  
{ Y Kp@ n8A  
nFileLength = getFileSize(); L.K|]]u  
if(nFileLength == -1) mKV31wvK}  
{ pK_zq  
System.err.println("File Length is not known!"); .),9a,  
} 'zMmJl}\vd  
else if(nFileLength == -2) j1+I_   
{ XS^du{ai  
System.err.println("File is not access!"); \7xc*v [  
} yEJ3O^(F  
else (~F}O  
{ "la0@/n  
for(int i=0;i<nStartPos.length;i++) :*|So5fs  
{ .Q@]+&`|}i  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); F>[^m Xw  
} )G]J@36  
for(int i=0;i<nEndPos.length-1;i++) Xf{p>-+DL  
{ \ E5kpm  
nEndPos = nStartPos[i+1]; "iK'O =M  
} 0lYP!\J3]%  
nEndPos[nEndPos.length-1] = nFileLength; PV=sqLM~  
} &n83>Q  
} RCK*?\m5  
}y+a )2  
OzRo  
//启动子线程 w+!V,lU"^  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :l Z\=2D  
for(int i=0;i<nStartPos.length;i++) "av/a   
{ e9S*^2;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^n4aoj  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wu{%gtx/;^  
nStartPos,nEndPos,i); xZV|QVY;  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); b!"qbC1  
fileSplitterFetch.start(); r<P?F  
} &js$qgY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |6Iw\YU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4{6,Sx  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", o ?.VW/"  
nEndPos = " + nFileLength); XJS^{=/  
// fileSplitterFetch[nPos.length-1].start(); _wW"Tn]  
$mf6!p4  
\sW>Y#9]  
//等待子线程结束 !@ AnwV]  
//int count = 0; b1=! "Y@  
//是否结束while循环 w`#9Re  
boolean breakWhile = false; L!ms{0rJ  
s6 K~I  
SST@   
while(!bStop) 4m~p(r  
{ (0?FZ.9%  
write_nPos(); 2U+Fa t@  
Utility.sleep(500); +f_3JL$  
breakWhile = true; V{qR/  
qCm%};yt  
md : Wx  
for(int i=0;i<nStartPos.length;i++) DC$> 5FDv  
{ j \ #y  
if(!fileSplitterFetch.bDownOver) w/(2fU(  
{ nAj +HLO  
breakWhile = false; O=!EqaExW  
break; LR"7e  
} "oR%0pU*  
} }1sd<<\`  
if(breakWhile) $O\]cQD`u  
break; QNj6ETB-d  
sN1I+X  
AVc|(~V  
//count++; /" &Jf}r  
//if(count>4) [>QzT"=  
// siteStop(); *;T HD>  
} BBl9<ne$  
Fj <a;oV  
9Z3Y,`R,  
System.err.println("文件下载结束!"); x:]_z.5  
} H3ob 8+J  
catch(Exception e){e.printStackTrace ();} bD 1IY1  
} @_;vE(!5  
o O1Fw1Y  
i^}DIx{  
//获得文件长度 %IUTi6P l  
public long getFileSize() 6WLq>Jo  
{ 7Uh/Gl  
int nFileLength = -1; \ERHnh  
try{ ]XfROhgP=  
URL url = new URL(siteInfoBean.getSSiteURL()); *  }ZKQ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6:G ::"ew  
httpConnection.setRequestProperty("User-Agent","NetFox"); IU]@%jA_:A  
eGbjk~,f'  
DwXSlsN3v  
int responseCode=httpConnection.getResponseCode(); (xBWxeL~  
if(responseCode>=400) DpL|aRdbK  
{ "j}fcrlG9  
processErrorCode(responseCode); @iYr<>iDZ  
return -2; //-2 represent access is error a 0qDRB  
} r$!  
re@OPiXa v  
\e?w8R.6w^  
String sHeader; G`u";w_  
\!r,>P   
*;<oM]W_  
for(int i=1;;i++) k3e?:t 9  
{ rPJbbV",+^  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); nqib`U@"  
//Utility.log(in.readLine()); ~_4$|WKl  
sHeader=httpConnection.getHeaderFieldKey(i); {'f=*vMI  
if(sHeader!=null) MrS~u  
{ glNXamo  
if(sHeader.equals("Content-Length")) { %af  
{ ;J?zD9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mS-{AK  
break; 1jj.oa]  
} R"JT+m  
} (V8lmp-F  
else {F*81q\  
break; Q$^Kf]pD  
} (#r>v h(  
} 9J f.Ls  
catch(IOException e){e.printStackTrace ();} #)<WQZ)  
catch(Exception e){e.printStackTrace ();} :c&F\Q=  
zCpXF< _C  
53?B.\  
Utility.log(nFileLength); 6vZ.CUK9  
/q6 ^.>b  
um mkAeWb  
return nFileLength; _n3"  
} E&2mFg  
FZJ sZeO  
sfEy  
//保存下载信息(文件指针位置) rp,PhS  
private void write_nPos() .h>tef  
{ 7?~*F7F  
try{ h#I]gHQK  
output = new DataOutputStream(new FileOutputStream(tmpFile)); /Os;,g  
output.writeInt(nStartPos.length); f\M;m9{(  
for(int i=0;i<nStartPos.length;i++) Kd^,NAg  
{ G\o *j |  
// output.writeLong(nPos); eTY" "EWU  
output.writeLong(fileSplitterFetch.nStartPos); %0^taA  
output.writeLong(fileSplitterFetch.nEndPos); ch:0qgJ  
} oxgh;v*  
output.close(); UhF+},gU  
} sT%^W  
catch(IOException e){e.printStackTrace ();} oi/bp#(fa  
catch(Exception e){e.printStackTrace ();} ADVHi3b  
} "_36WX  
Uz; pNWMk  
Bis'59?U_  
//读取保存的下载信息(文件指针位置) `]l*H3+hg  
private void read_nPos() pe7R1{2Q_s  
{ DM)%=C6<  
try{ 6 2#dSd}HG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); s*.&DN  
int nCount = input.readInt(); $tFmp)  
nStartPos = new long[nCount]; c/ABBvd|  
nEndPos = new long[nCount]; !$^LTBOH3  
for(int i=0;i<nStartPos.length;i++) m}>#s3KPA  
{ zD}2Zh]  
nStartPos = input.readLong(); D= LLm$y  
nEndPos = input.readLong(); [(4s\c  
} '6W|,  
input.close(); , aQ{  
} ~OQ/ |ws  
catch(IOException e){e.printStackTrace ();} (cEjC`]  
catch(Exception e){e.printStackTrace ();} QGQ}I  
} uf&Ke k,  
K trR+ :  
fp2.2 @[  
private void processErrorCode(int nErrorCode) I2<t?c:Pn<  
{ 0!!z'm3  
System.err.println("Error Code : " + nErrorCode); >`!Lh`n7_  
} (}NKW  
mk&`dr  
8 ,<F102(  
//停止文件下载 kc&MO`2 W\  
public void siteStop() xHY#"   
{ o+T %n1$+V  
bStop = true; 8<Yqpb  
for(int i=0;i<nStartPos.length;i++) OKp0@A)8  
fileSplitterFetch.splitterStop(); {Kkut?5  
2YL)" w  
v08Xe*gNU  
} ;`MKi5g  
} fu6Ir,  
//负责部分文件的抓取 57eA (uI  
**FileSplitterFetch.java b63tjqk  
*/ 5t&;>-A'?'  
package NetFox; 12MWO_'g8  
MehMhHY  
vpl> 5%  
import java.io.*; 3BWYSJ|  
import java.net.*; y7)$~R):-  
yw9)^JU8"  
z&r@c-l@  
public class FileSplitterFetch extends Thread { ES&"zjr$  
*D$[@-7  
'qT[,iQ  
String sURL; //File URL 9 EqU 2~  
long nStartPos; //File Snippet Start Position ?$&iVN^UA  
long nEndPos; //File Snippet End Position iO_6>&(  
int nThreadID; //Thread's ID kX)Xo`^Ys  
boolean bDownOver = false; //Downing is over |Q)c{9sD  
boolean bStop = false; //Stop identical l;C00ZBOc  
FileAccessI fileAccessI = null; //File Access interface Xitsb f=Gg  
M@b:~mI[sw  
 UX& ?^]  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException bzt(;>_8  
{ K_X10/#b&  
this.sURL = sURL; Pa-p9]gq  
this.nStartPos = nStart; Lupug"p0   
this.nEndPos = nEnd; 5D#Mhgun  
nThreadID = id; y6*9, CF  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 6+hx64 =  
} gwyHDSo8:a  
b^~"4fU  
-'iV-]<  
public void run() - P$mN6h  
{ K4\#b}P!  
while(nStartPos < nEndPos && !bStop) aV9QIH~  
{ ^k7`:@ z0U  
z|:3,$~sN  
qfQg?Mr  
try{ ,J3s1 ]~^  
URL url = new URL(sURL); <.yL&$9  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yRt>7'@X  
httpConnection.setRequestProperty("User-Agent","NetFox"); @d]a#ypU  
String sProperty = "bytes="+nStartPos+"-"; dq&N;kk |  
httpConnection.setRequestProperty("RANGE",sProperty); ^t'mfG|DV  
Utility.log(sProperty); :t36]NM  
PfRe)JuB  
"ApVgNB  
InputStream input = httpConnection.getInputStream(); E0Y>2HOuL  
//logResponseHead(httpConnection); xy$agt>j>  
`Z 3p( G  
A*r6  
byte[] b = new byte[1024]; &2EimP  
int nRead; k15B5  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ; n)9  
{ d/fg  
nStartPos += fileAccessI.write(b,0,nRead); n\ yDMY  
//if(nThreadID == 1) u\9t+wi}<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `(rnD  
} XDWR ]  
fi6i{(K  
1D6F WYV8  
Utility.log("Thread " + nThreadID + " is over!"); 0A}'@N@G)  
bDownOver = true; _4]GP3`  
//nPos = fileAccessI.write (b,0,nRead); l,pI~A`w_  
} LR5X=&k  
catch(Exception e){e.printStackTrace ();} B?c n5  
} $ MN1:ih  
} ah (lH5r  
CQ`$' oy?W  
<oc"!c;T  
//打印回应的头信息 xElHYh(\  
public void logResponseHead(HttpURLConnection con) 4*K~6Vh  
{ 5w# Ceg9  
for(int i=1;;i++) 2tq~NA\#t  
{ Kn !n}GtR  
String header=con.getHeaderFieldKey(i); 0"*!0s ~  
if(header!=null) rLU+-_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Y30e7d* qr  
Utility.log(header+" : "+con.getHeaderField(header)); E9]/sFA-]  
else ZT \=:X*e  
break; "5+x6/9b  
} Z?7XuELKV  
} yJj$iri  
Vlk]  
e95x,|.-_  
public void splitterStop() ># {,(8\  
{ &ZmHR^Flz  
bStop = true; 91 ]"D;NN  
} ;U02VguC  
1${lHVx]  
_.ny<r:g  
} xzqgem`[\  
U=<d;2N#  
X~`<ik{q  
/* *Z+8L*k97  
**FileAccess.java jI-\~  
*//文件访问(定位,写) PW[NW-S`c  
package NetFox; `H_.<``>  
import java.io.*; P2q'P&  
`pHlGbrW  
2Op\`Ht &  
public class FileAccessI implements Serializable{ wcdD i[E>i  
s C/5N  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ?W#>9WQi  
RandomAccessFile oSavedFile; RW#&f*  
long nPos; 5L'bF2SI  
Y'75DE<BC  
x2^Yvgc-  
public FileAccessI() throws IOException Guc~] B  
{ 3( Y#*f|  
this("",0); *5\k1-$  
} C1/<t)^  
y}'c)u  
%,l+?fF  
public FileAccessI(String sName,long nPos) throws IOException &s +DK `  
{ <rO0t9OH  
oSavedFile = new RandomAccessFile(sName,"rw"); qB`-[A9HPe  
this.nPos = nPos; KNkVI K  
oSavedFile.seek(nPos); `YZK$ -,  
} TTJFF\$?  
m_ |:tU(t  
(#dwIBBFt  
public synchronized int write(byte[] b,int nStart,int nLen) _o 2pyV&  
{ kiW|h)w_,v  
int n = -1; ]/o0p  
try{ MQ9Nn|4  
oSavedFile.write(b,nStart,nLen); t3~ZGOn  
n = nLen; bD&^-& G  
} Qj?qWVapA  
catch(IOException e) -FAAP&LG  
{ YPjjSi:#  
e.printStackTrace (); C&&*6E5  
} R::0.*FF  
7+,6 m!4  
nK@RFU6  
return n; / _N*6a~  
} )9^0Qk' ]  
BD)5br].  
rQ^X3J*`  
} =Me94w>G3X  
V/=NIeSE  
{Z529Ns  
/* :GXD-6}^|  
**SiteInfoBean.java \m>mE/N  
*/ QbF!V%+a's  
package NetFox; h83;}>  
'u \my  
&0E>&1`7  
public class SiteInfoBean { *u2pk>y)  
[7K-L6X  
X-tc Ud  
private String sSiteURL; //Site's URL ,[64$=R8  
private String sFilePath; //Saved File's Path MOiTz L*  
private String sFileName; //Saved File's Name Ur`jmB  
private int nSplitter; //Count of Splited Downloading File o3_dHbdI  
O4Wn+$AN  
VSK!Pc.G}  
public SiteInfoBean() v<*ga7'S  
{//nSplitter的缺省值为5 WBo|0(#  
//default value of nSplitter is 5 .>5KwEK~  
this("","","",5); 7*!h:rg  
} xq?9w$  
rmX'Ym9#  
]BY^.!Y  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) H nKO  
{ `^rN"\  
sSiteURL= sURL; ]kJinXHW  
sFilePath = sPath; sH//*y  
sFileName = sName; &rTOJ 1)V}  
this.nSplitter = nSpiltter; C^}2::Qu  
To x{Sk3L  
SJYy,F],V"  
} R]0p L   
`N+A8  
bNUb  
public String getSSiteURL() mkA1Sh{hX>  
{ //SH=>w2  
return sSiteURL; x@-bY  
} aoLYw 9  
g4NxNjM;  
}U)g<Kzh  
public void setSSiteURL(String value) >L\>Th{o  
{ =}:9y6QR.  
sSiteURL = value; Y9b|lP7!  
} uQ^r1 $#  
*W'F 6Hpu  
a3&&7n  
public String getSFilePath() 2"31k2H[  
{ y"|QY!fK  
return sFilePath; z9@Tg= #i  
} $1QQidB  
`MMh"# xN  
@yBg)1AL  
public void setSFilePath(String value) &3 QdQ n,  
{ QJBzv|  
sFilePath = value; F9hh- "(Z  
} *O>OHX  
n:hHm,  
~! *xi  
public String getSFileName() byj}36LN62  
{ JGP<'6"L$  
return sFileName; NVEjUt/  
} +- ~:E_G  
WaU+ZgDrG  
#WBlEVx;Z  
public void setSFileName(String value) _JlbVe[<  
{ taS2b#6\+  
sFileName = value; BPp`r_m8w}  
} k4|9'V&1*6  
vqq7IV)|  
[dm&I#m=  
public int getNSplitter() kB|j N~  
{ 1 11s%  
return nSplitter; #cG7h(!  
} XcoV27  
U@W3x@  
~9&#7fU  
public void setNSplitter(int nCount) `>M-J-J  
{ m).S0  
nSplitter = nCount; "62vwWrwO  
} AlW0GK=N-p  
} Eei"baw/  
.ZuRH_pI  
r(ej=aR  
/* )E--E+j  
**Utility.java )ZxDfRjL  
*/ Xb0$BAP  
package NetFox; 72hN%l   
d|GQZAEJEt  
(w31W[V'#  
public class Utility { V3%"z  
3 ;M7^DM  
<eU1E }BDQ  
public Utility() \Tf$i(0q  
{ .\r=1HZ3  
9FB[`}  
 yN9k-IPI  
} 'H"wu /#  
"m*.kB)e7  
//线程睡眠 \;al@yC=T  
public static void sleep(int nSecond) r)ni;aP  
{ cL31g_u  
try{ XCCh*qym  
Thread.sleep(nSecond); m3Mo2};?  
} 8(yZX4OH>  
catch(Exception e) VMry$  
{ g"k1O  
e.printStackTrace (); 8>T#sO?+  
} +D[|Mi  
} |eN#9Bm  
5a$Q}!6E.Y  
//日志 X9W'.s.[Q  
public static void log(String sMsg) UDjmXQ2,  
{ ~7!=<MW  
System.err.println(sMsg); \!!qzrq  
} QucDIZ  
|Z]KF>S]  
L-B"P&  
public static void log(int sMsg) xvP=i/SO  
{  ]/l"  
System.err.println(sMsg); "Di27Rq  
} :O`7kZ]=n  
} ~d0:>8zQR  
OT1  
~UrKyA  
/* l@;UwnI  
**TestMethod.java #[|~m;K(w  
*/ 4@2<dw|*h  
package NetFox; j7(sYo@x7  
` Aa}q(}k  
kF%EJuu  
public class TestMethod { U_s3)/'  
MQs!+Z"m>  
#Tc]L<."  
public TestMethod() 8fV.NCyE  
{ ///xx/weblogic60b2_win.exe o1Bn^ w  
try{ nWfzwXP>_  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); j@N z  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); CSKOtqKQ)  
SiteFileFetch fileFetch = new SiteFileFetch(bean); C`G+b{o  
fileFetch.start(); fL0dy[Ch@  
} 9((BOq  
catch(Exception e){e.printStackTrace ();} ~ m/nV81  
Xk9mJ]31LC  
lk.]!K$}  
} wM$N#K@  
`ChS$p"A  
mf~Joluc J  
public static void main(String[] args) a ~s:f5S>  
{ _&(\>{pm  
new TestMethod(); xwuGJ   
} [ B{F(~O  
} v|!u]!JM  
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