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http断点续传简单实现(java)

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/* bA9dbe  
**SiteFileFetch.java 6I.+c  
*/ Fb4S /_ V  
package NetFox; -){^ Q:u  
import java.io.*; oIR%{`3"I  
import java.net.*; 58gt*yVu  
vH\nL>r  
O7_NXfh|  
public class SiteFileFetch extends Thread { Zo6a_`)d  
^J=txsx  
sAAIyPJts  
SiteInfoBean siteInfoBean = null; //文件信息Bean ewlc ^`  
long[] nStartPos; //开始位置 Q^5 t]HKn  
long[] nEndPos; //结束位置 &7y1KwfXn  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 WRyv >Y  
long nFileLength; //文件长度 `fE:5y  
boolean bFirst = true; //是否第一次取文件 E ^>7jf09,  
boolean bStop = false; //停止标志 L$07u{Q  
File tmpFile; //文件下载的临时信息 9!OCilG  
DataOutputStream output; //输出到文件的输出流 .;sPG  
k/rkJ|i+p  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) {}gk4 xr  
public SiteFileFetch(SiteInfoBean bean) throws IOException :QY9pT  
{ fHp#Gi3Lz  
siteInfoBean = bean; \Hx#p`B%  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath()));  k`zK  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ON=ley  
if(tmpFile.exists ()) y&|{x "  
{ 5UD;Z V%  
bFirst = false; 8i 'jkyInT  
read_nPos(); leqSS}KU+  
} CMf~Yv  
else "+"dALX{3K  
{ H_$f v_  
nStartPos = new long[bean.getNSplitter()]; 7.'j~hJL  
nEndPos = new long[bean.getNSplitter()]; x~,?Zj)n?C  
} ll^O+>1dO  
e/I{N0SR  
o~N-x*   
`-e}:9~q  
} IaqN@IlWb  
Z s!q#qM  
#Yb9w3N  
public void run() *wl_8Sis}  
{ r,@|Snv)  
//获得文件长度 t#Yh!L6>  
//分割文件 S^_yiV S  
//实例FileSplitterFetch lk'jBl%  
//启动FileSplitterFetch线程 :EAfD(D{)  
//等待子线程返回 BiAcjN:Z  
try{  ]@ 0V  
if(bFirst) xGQ:7g+qu  
{ C 5!6k1TcE  
nFileLength = getFileSize(); 3]82gZG G  
if(nFileLength == -1) ( I~XwP&  
{ e/l?|+m 6  
System.err.println("File Length is not known!"); 4p g(QeR  
} s0'U[]  
else if(nFileLength == -2) wY)GX  
{ nr6[rq  
System.err.println("File is not access!"); C /VXyl@o  
} bJ[1'Es `  
else u9%:2$[  
{ \3UdC{~  
for(int i=0;i<nStartPos.length;i++) 5WX2rJ8z  
{ Cf 8 - %  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _$x *CP0(  
} C_&tOt  
for(int i=0;i<nEndPos.length-1;i++) NWcF9z%@  
{ D'=`O6pK  
nEndPos = nStartPos[i+1]; JIkmtZv  
} (bXp1*0 ;  
nEndPos[nEndPos.length-1] = nFileLength; wn.0U  
} F= lj$?4{  
}  5Ww\h  
7}?z=LHb3  
s7gf7 E#Y  
//启动子线程 LD"}$vfs  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; g[Y$SgJ  
for(int i=0;i<nStartPos.length;i++) !SNtJi$;v  
{ p_N=V. w  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), z#!Cg*K(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5rhdm?Ls0  
nStartPos,nEndPos,i); r F - yD1  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e6/} M3B  
fileSplitterFetch.start(); 3<SC`6'?  
} m)2U-3*iX  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -M9 4 F  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?q6eV~P  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 79fg%cSb  
nEndPos = " + nFileLength);  vpMv  
// fileSplitterFetch[nPos.length-1].start(); ^u<+tV   
Mqy`j9FbL  
smNr%}_g  
//等待子线程结束 a+Nd%hoe  
//int count = 0;  EZFWxR/  
//是否结束while循环 )FCqYCfk  
boolean breakWhile = false; ]].21  
suSIz 7:  
MS)bhZvO  
while(!bStop) W>49,A,q  
{ {,X(fJ  
write_nPos(); 1jb@n xRjO  
Utility.sleep(500);  O@$i  
breakWhile = true; AEJm/8,T  
^u74WN  
mUw,q;{  
for(int i=0;i<nStartPos.length;i++) _X/`4 G  
{ _Fjv.VQ,  
if(!fileSplitterFetch.bDownOver) ]QQ"7_+  
{ NI)nf;C  
breakWhile = false; ZvJx01F{  
break; +d96Z^KUhv  
} bHNaaif}P  
} dWSH\wm+  
if(breakWhile) M`FL&Ac  
break; #wfR$Cd  
|Ca n  
<o O_wS@:  
//count++; +{Ttv7l_2  
//if(count>4) @nK 08Kj-  
// siteStop(); }ls>~uN  
} AmHIG_'  
L\5n!(,0  
UWp(3FQ  
System.err.println("文件下载结束!"); XR(kR{yo  
} h";sQ'us  
catch(Exception e){e.printStackTrace ();} 191)JWfa  
} ;pJ7k23(  
KAGq\7  
lK0coj1+  
//获得文件长度 9b>a<Z  
public long getFileSize() 0FBifK  
{ U.\kAEJ  
int nFileLength = -1; "cZ.86gG`:  
try{ FK>r c3 q  
URL url = new URL(siteInfoBean.getSSiteURL()); C|+5F,D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :HC{6W`$  
httpConnection.setRequestProperty("User-Agent","NetFox"); rHznXME$wZ  
w$_ooQ(_;Q  
LF8B5<[O  
int responseCode=httpConnection.getResponseCode(); % rkUy?=vu  
if(responseCode>=400) 3JwmLGj}  
{ TX;|g1K  
processErrorCode(responseCode); |"arVde  
return -2; //-2 represent access is error +-ue={ '  
} Mppb34y  
xJ4T7 )*  
`y4+OXZ^  
String sHeader; YS9|J=!~  
,+XQ!y%  
.d;/6HD[y  
for(int i=1;;i++) w] VvH"?  
{ &}WSfZ0{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Q"KH!Bu%P  
//Utility.log(in.readLine()); *%8dW  
sHeader=httpConnection.getHeaderFieldKey(i); FBe 1f1 sm  
if(sHeader!=null) y<Z8+/f`f  
{ r*$KF!-dg  
if(sHeader.equals("Content-Length")) f?)qZPM  
{ =^6]N~*,D  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -k'=s{iy  
break; 6;ICX2Wq'  
} ZC05^  
} o9JJ_-O"  
else }a8N!g  
break; r3|vu"Uei  
} r]TeR$NJ  
} mIOx)`$  
catch(IOException e){e.printStackTrace ();} 2e+DUZBoC  
catch(Exception e){e.printStackTrace ();} | r2'B  
O *CKyW_$t  
[qc90)^Q,  
Utility.log(nFileLength); wEk9(|  
'kp:yI7w  
|>m@]s7Z  
return nFileLength; ?=6zgb"9-  
} /@q_`tU  
B<i1UJ5  
? ;\YiOTda  
//保存下载信息(文件指针位置) ]ko>vQ4]3  
private void write_nPos() M^H357r%  
{ /6g*WX2P1  
try{ o;}o"-s  
output = new DataOutputStream(new FileOutputStream(tmpFile)); azN<]u@.  
output.writeInt(nStartPos.length); yhZ2-*pTg  
for(int i=0;i<nStartPos.length;i++) 6*CvRb&  
{ ;R}:2  
// output.writeLong(nPos); .#CTL|x  
output.writeLong(fileSplitterFetch.nStartPos); y "gYv  
output.writeLong(fileSplitterFetch.nEndPos); a&9+<  
} ho 4~-xmN  
output.close(); C&r&&Pw  
} g\d|/HV K  
catch(IOException e){e.printStackTrace ();} %vgn>A?]1  
catch(Exception e){e.printStackTrace ();} h ~v8Q_6  
} c.r]w  
K%)u zP  
0jG8Gmh!  
//读取保存的下载信息(文件指针位置) 4; y*y tY*  
private void read_nPos() L `3x0u2  
{ ~Cm_=[  
try{  K<6)SL4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); [s"xOP9R  
int nCount = input.readInt(); K8daSvc  
nStartPos = new long[nCount]; XC%u`UG  
nEndPos = new long[nCount]; ch!/k  
for(int i=0;i<nStartPos.length;i++) f }P6P>0T  
{ 67?O}~jbG  
nStartPos = input.readLong(); ) 7w%\i{M  
nEndPos = input.readLong(); nF`_3U8e  
} K+p7yZJ  
input.close(); }}G`yfs}r  
} c>mTd{Abi  
catch(IOException e){e.printStackTrace ();} v4OroG=^  
catch(Exception e){e.printStackTrace ();} #-W a3P  
} i_Ol vuy~  
~U}0=lRVS  
a'r8J~:jy  
private void processErrorCode(int nErrorCode) usc"m huQ  
{ n|q $=jE  
System.err.println("Error Code : " + nErrorCode); clyZD`*  
} _<}oBh  
n.F^9j+V  
K+|G9  
//停止文件下载 lsq\CavbM  
public void siteStop() L.X"wIs^  
{ 8Mg wXH  
bStop = true; SI\ O>a 9{  
for(int i=0;i<nStartPos.length;i++) <5BNcl\ZL  
fileSplitterFetch.splitterStop(); > >%m,F[  
'A2^K5`3  
m?GBvL$  
} NpI "XQ  
} !-B$WAV  
//负责部分文件的抓取 /3#)  
**FileSplitterFetch.java r^zra|]  
*/ %1h%#/#[  
package NetFox; `8M{13fv  
t.X8c/,;g  
jJbS{1z  
import java.io.*; &65I 6  
import java.net.*; e>J.r("f  
@KJ~M3d0l  
"d"6.ND  
public class FileSplitterFetch extends Thread { 46 [k9T  
7fE U5@  
;Vv.$mI  
String sURL; //File URL y8%QS*  
long nStartPos; //File Snippet Start Position tK7v&[cI  
long nEndPos; //File Snippet End Position wjy<{I  
int nThreadID; //Thread's ID ]Ub"NLYV  
boolean bDownOver = false; //Downing is over 0H!J  
boolean bStop = false; //Stop identical -RI&uFqOI  
FileAccessI fileAccessI = null; //File Access interface :yxP3e%rp  
4m1@lnjp  
 \uG^w(*)  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException yo^M>^P\N  
{ L5DeLF+  
this.sURL = sURL; <]Btx;}  
this.nStartPos = nStart; 6v?tZ&, G  
this.nEndPos = nEnd; 5D+rR<pD}"  
nThreadID = id; FeL!%z  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ?uh%WN6nU]  
} =[do([A  
aE(DNeG-H  
<5O:jd  
public void run() P1_6:USBM  
{ &[b(Lx|i  
while(nStartPos < nEndPos && !bStop) t9~Y ?  
{ *)bh6b=7  
VW\xuP  
T3bYj|rh=  
try{ w5<&b1:  
URL url = new URL(sURL); aOhi<I`*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lK Ry4~O  
httpConnection.setRequestProperty("User-Agent","NetFox"); VPvQ]}g6k  
String sProperty = "bytes="+nStartPos+"-"; W %<,GV  
httpConnection.setRequestProperty("RANGE",sProperty); r;~7$B)  
Utility.log(sProperty); W#9A6ir>  
g|Xjw Ti8$  
C23Gp3_0/  
InputStream input = httpConnection.getInputStream(); zX8'OoEH*9  
//logResponseHead(httpConnection); `D $ "K1u  
Y>2oU`ly,  
QC Jf   
byte[] b = new byte[1024]; h^v+d*R N  
int nRead; E3V_qT8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'i:S=E F  
{ f]NaQ!. 7  
nStartPos += fileAccessI.write(b,0,nRead); xey?.2K1A  
//if(nThreadID == 1) * `3+x  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Owz>g4l r  
} |33_="  
{Q021*xt/  
bQ`2ll*(  
Utility.log("Thread " + nThreadID + " is over!"); '$h0l-mQ  
bDownOver = true; }6To(*  
//nPos = fileAccessI.write (b,0,nRead); ;>CM1  
} m`&6[[)6~  
catch(Exception e){e.printStackTrace ();} RveEA/&&  
} mXT{c=N)w  
} L"L a|  
a(_3271  
' -td/w  
//打印回应的头信息 ^!6T,7 B B  
public void logResponseHead(HttpURLConnection con) ]D_ AZI  
{ =AP0{  
for(int i=1;;i++) [{PmU~RMYf  
{ Iu ve~ugO  
String header=con.getHeaderFieldKey(i); 3Vk<hBw2  
if(header!=null) awgS5We|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _iH:>2p5R  
Utility.log(header+" : "+con.getHeaderField(header)); lm8<0*;,  
else ({<qs}H"  
break; | MXRNA~  
} UYH&x:WEd  
} .2 }5Dc,eR  
? @- t.N  
]Wn=Oc{F  
public void splitterStop() 2,rjy|R`  
{ xJ^pqb  
bStop = true; %'MR;hQsd8  
} .*Axr\x3  
wKE}BO >  
W]5sqtF;6  
} [Qn=y/._r  
)U+&XjK  
@4wN-T+1  
/* $aY:Z_s  
**FileAccess.java DfZ)gqp/Av  
*//文件访问(定位,写) \|7Y"WEQ  
package NetFox; T^@P.zX  
import java.io.*; `aL4YH-v  
iza.' Mm~  
TUi<  
public class FileAccessI implements Serializable{ `;Xwv)  
K 5AArI  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Ym wb2]M  
RandomAccessFile oSavedFile; -:Jn|=  
long nPos; ]m\:XhI*<  
S~ZRqL7Z O  
w1)SuMFK_  
public FileAccessI() throws IOException i%otvDn1  
{ t+aE*Q  
this("",0); Fv3:J~Yf  
} O7xBMqMf  
`l-R?C?*!  
xeSv+I-b  
public FileAccessI(String sName,long nPos) throws IOException }/VSIS@Z  
{ m8 Ti{w(  
oSavedFile = new RandomAccessFile(sName,"rw"); 5wI j:s  
this.nPos = nPos; &P(vm@*  
oSavedFile.seek(nPos); 9=G dj!L  
} @l?2",  
g?9%_&/})A  
JT*Pm"}  
public synchronized int write(byte[] b,int nStart,int nLen) ~!ICBF~j  
{ S^ JUQx7  
int n = -1; +zzS  
try{ 8_uh2`+Bvb  
oSavedFile.write(b,nStart,nLen); PF] Vt  
n = nLen; vW03nt86  
} .KxE>lJbqM  
catch(IOException e) sX#7;,Ft7  
{ % ^&D,  
e.printStackTrace (); *Vp$#Rb  
} D}K/5iU]a  
y5:al7*P  
MJ~)CiKgN  
return n; `bEum3l\6]  
} -P$E)5?^  
Yd$64d7,h  
N0&#fXO  
} K9Bi2/N  
?]2OT5@&s  
D;OR?NdgvW  
/* #mbl4a  
**SiteInfoBean.java 'q*:+|"  
*/ E']Gh  
package NetFox; i ,g<y  
6| {uZNz  
d5tp w$A  
public class SiteInfoBean { p&(~c/0  
c$]NXKcA  
Zbjj>*2%^  
private String sSiteURL; //Site's URL f n'N^  
private String sFilePath; //Saved File's Path }{@RO./)[  
private String sFileName; //Saved File's Name O:(%m  
private int nSplitter; //Count of Splited Downloading File QLAyX*%B  
'gv7&$X}4  
OvW/{  
public SiteInfoBean() bHH=MLZR:  
{//nSplitter的缺省值为5 .@;,'Xw1~  
//default value of nSplitter is 5 >jBnNA@  
this("","","",5); o!M*cyq  
} AZadNuL/  
T#w *5Qf  
d^jIsE`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g6 3?(+Fz  
{ {>=#7e-]  
sSiteURL= sURL; c}g:vh  
sFilePath = sPath; X5eTj  
sFileName = sName; }lt]]094,  
this.nSplitter = nSpiltter; N3g?gb"Ex)  
QTjOLK$e$  
!;YQQ<D  
} 2\=cv  
T+|V;nP.  
05m/iQ  
public String getSSiteURL() {cBLm/C  
{ h\^> s$  
return sSiteURL; r&-I r3[  
} },5_h0  
7w=%aW|  
S+C^7# lT  
public void setSSiteURL(String value) to*<W,I  
{ U[8Cg  
sSiteURL = value; ()+;KF8  
} @7 *Ag~MRb  
er0ClvB  
n"{oj7E0a  
public String getSFilePath() :}18G}B  
{ GQ8r5V4:  
return sFilePath; `g iCytv  
} q3E_.{t  
'((Ll  
g1`/xJz|  
public void setSFilePath(String value) @Q atgYu  
{ #/9(^6f:  
sFilePath = value; R4|<Vp<U2  
} x 1"ikp}  
GX lFS#`  
'yM)>]u"  
public String getSFileName() $zBG19 [%  
{ \HOOWaapN  
return sFileName; E$[\Fk}S  
} Az2$\  
< &'r_m  
R`:NUGR  
public void setSFileName(String value) ^50/.Z >  
{ ;pNHT*>u,  
sFileName = value; $|YIr7?R  
} /-39od0  
tnmuCz  
N+PW,a  
public int getNSplitter() ?%h JZm;  
{ g~@0p7]Y  
return nSplitter; {P#&e>)v{  
} RfB""b8]=  
=#<hT s  
'gojP  
public void setNSplitter(int nCount) 5Ffz^;i  
{ u-h3xj  
nSplitter = nCount; 9Yowz]')  
} `8TM<az-L  
} $E4W{ad2jW  
K,}"v ;||  
sHrpBm&O4  
/* (;a O%  
**Utility.java O.E   
*/ `B6{y9J6  
package NetFox; rQ'tab.,]  
v) q6  
WU1o4&OF  
public class Utility { K0\a+6kh  
Wx/!My u  
&hba{!`y  
public Utility() WL}6YSC  
{ =D4EPfQn1  
7`tnoTUv  
_A)<"z0E  
} XI\aZ\v  
Rhx7eU#&  
//线程睡眠 d #a  
public static void sleep(int nSecond) Ik1,?A  
{ h{sW$WA  
try{ 2ezuP F  
Thread.sleep(nSecond); WytCc>oL  
} n a2"Sy=Yi  
catch(Exception e) -H`G6oMOO  
{ R\:C|/6f  
e.printStackTrace (); [ylGNuy  
} VSZ6;&2^  
} RQ{w`> K  
S/d})8~.  
//日志 S53%*7K.  
public static void log(String sMsg) ["Q8`vV0WO  
{ J5Fg]O*  
System.err.println(sMsg); '{cN~A2b4  
} dtM@iDljj  
%1VMwqC]E  
BdO$  
public static void log(int sMsg) e|Sg?ocR  
{ ].dTEzL9X  
System.err.println(sMsg); e^XijId.  
} Ti3BlWQH  
} {u.V8%8  
0uU%jN$  
4&ea*w  
/* k #*|-?  
**TestMethod.java YF>t{|  
*/ C3@.75-E  
package NetFox; F`I-G~e  
r$v?[x>+K  
[k'Ph33c  
public class TestMethod { c(#`z!FB  
<YeF?$S}  
G<jpJ  
public TestMethod() U-FA^c;  
{ ///xx/weblogic60b2_win.exe 6@XutciK  
try{ pXFNK" jm  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); N^ D/}n  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Xb^\{s?b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d BlOU.B  
fileFetch.start(); U*&ZQw  
} {yb\p9q{Yo  
catch(Exception e){e.printStackTrace ();} YRp\#pVnZ  
J82{PfQ"  
~2H7_+.#  
} Jl]]nO BQ/  
kmc9P&  
u=E?N:I~F  
public static void main(String[] args) '-i tn  
{ =|U2 }U;  
new TestMethod(); R ^B2J+O  
} @i{JqHU"  
} ImV54h'  
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