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http断点续传简单实现(java)

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/* W,oV$ s^  
**SiteFileFetch.java 8#JyK+NU  
*/ LF,c-Cv!jL  
package NetFox; 'w$we6f  
import java.io.*; apWrcaj  
import java.net.*; @Oc}\Rg  
N|# x9mE  
ne~#{q  
public class SiteFileFetch extends Thread { GH)+yD[o  
~|d?o5W  
[`n yq)  
SiteInfoBean siteInfoBean = null; //文件信息Bean PT*@#:MA  
long[] nStartPos; //开始位置 +z/73s0~  
long[] nEndPos; //结束位置 rN!9&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 UtW3KvJ#=  
long nFileLength; //文件长度 +wgUs*(W  
boolean bFirst = true; //是否第一次取文件 1~iBzPU2  
boolean bStop = false; //停止标志 /SM#hwFxJ&  
File tmpFile; //文件下载的临时信息 &7y1KwfXn  
DataOutputStream output; //输出到文件的输出流 =8 1Xt1,  
7&U+f:-w  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) E ^>7jf09,  
public SiteFileFetch(SiteInfoBean bean) throws IOException L$07u{Q  
{ 9!OCilG  
siteInfoBean = bean; .;sPG  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); k/rkJ|i+p  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); {}gk4 xr  
if(tmpFile.exists ()) Dg4^ C  
{ v?'k)B  
bFirst = false; |8?{JKsg  
read_nPos(); ,T>2zSk  
} si4=C  
else Yy:sZJ  
{ = |zyi|  
nStartPos = new long[bean.getNSplitter()]; us *l+Jw,m  
nEndPos = new long[bean.getNSplitter()]; K?<Odw'k  
} ov.rHVeI  
L7'X7WYf&  
4 6JP1  
) W7H{#  
} ;7{wa]  
hzVr3;3Zn  
VTkT4C@I;Y  
public void run() F>{uB!!L4  
{ BP><G^  
//获得文件长度 y,eoTmaI  
//分割文件 {*  _ W  
//实例FileSplitterFetch uPD_s[  
//启动FileSplitterFetch线程 \nt'I;f  
//等待子线程返回 WED7]2>  
try{ gM]/Y6 *$b  
if(bFirst) \FX3=WW  
{ xg!\C@$  
nFileLength = getFileSize(); VH*(>^Of F  
if(nFileLength == -1) 5 `mVe0uI  
{ i; uM!d}  
System.err.println("File Length is not known!"); ;Awzm )Q  
} ;{u#~d}  
else if(nFileLength == -2) ( I~XwP&  
{ 8#3cmpx4  
System.err.println("File is not access!"); b8Ad*f\  
} 3Jit2W4  
else o[*ih\d  
{ eh=bClk  
for(int i=0;i<nStartPos.length;i++) nr%^:u  
{ ,$*klod  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); o{,(`o.1O  
} E 4(muhY  
for(int i=0;i<nEndPos.length-1;i++) {_D'\i(Y_  
{ BbhdGFG1  
nEndPos = nStartPos[i+1]; 6iS+3+  
} gU$3Y#R  
nEndPos[nEndPos.length-1] = nFileLength; Z.19v>-c  
} SaScP  
} rV{e[fGd  
N1+]3kt ~  
N1t:i? q&  
//启动子线程 je0 ?iovY  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Tdp$laPO'  
for(int i=0;i<nStartPos.length;i++) Q 7?4GxMj  
{ 0;`PHNBq  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Fsdn2{g8U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !T1i_  
nStartPos,nEndPos,i); $ :P~21,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cA^7}}?e  
fileSplitterFetch.start(); XBBRB<l)  
} TMs\#  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), [r~l O@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4iPg_+  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", UY^f|f&  
nEndPos = " + nFileLength); qTex\qP  
// fileSplitterFetch[nPos.length-1].start(); mQ)l`w Gh  
MYm6C;o$  
jP]'gQ!-w  
//等待子线程结束 8BdeqgU/_  
//int count = 0; kF7Al]IgT  
//是否结束while循环 Yf9L~K  
boolean breakWhile = false; W12K93tO  
>.A:6  
cZ,_O~  
while(!bStop) l#:Q V:  
{ r#}%sof  
write_nPos(); mcracj[ B  
Utility.sleep(500); Q?q m~wD  
breakWhile = true; m]vr|:{6/  
Sy~Mh]{E  
IT"jtV  
for(int i=0;i<nStartPos.length;i++)  EZFWxR/  
{ \/G Y0s  
if(!fileSplitterFetch.bDownOver) ld6@&34  
{ W6>uLMUa  
breakWhile = false; l\GNd6)H  
break; l{yPO@ut`F  
} [J#(k`@  
} p*,mwKN:  
if(breakWhile) W>49,A,q  
break; XsCbA8Qv  
:zoX Xo  
'LI)6;Yc  
//count++; Plv+mb  
//if(count>4) w9BH>56/"  
// siteStop(); _69\#YvCG  
} i vk|-C'\  
mUw,q;{  
L i^V?  
System.err.println("文件下载结束!"); XDQ1gg`  
} YKk%;U*  
catch(Exception e){e.printStackTrace ();} t~M_NEPxV  
} $P~a   
NI)nf;C  
i=UJ*c  
//获得文件长度 }mK_d9dx  
public long getFileSize() + u+fEg/A  
{ x(~l[hT  
int nFileLength = -1; G[ea@u$?  
try{ [8n4lE[)"  
URL url = new URL(siteInfoBean.getSSiteURL()); UYUd IIoL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |@F<ajlV  
httpConnection.setRequestProperty("User-Agent","NetFox"); Y_B( R  
5 Da( DA  
[d}1Cq=_  
int responseCode=httpConnection.getResponseCode(); \~>#<@h  
if(responseCode>=400) UK/k?0  
{ ;'kH<Iq  
processErrorCode(responseCode); d0d2QRX  
return -2; //-2 represent access is error YVi]f2F%  
} AnQRSB (  
#e[5O| V~  
i\b2P2 `B  
String sHeader; MaM7u:kD#  
a6C ~!{'nW  
BVDo5^&W  
for(int i=1;;i++) wim}}^H  
{ 8?!Vr1x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); c`cPGEv  
//Utility.log(in.readLine()); P? n`n!qZ  
sHeader=httpConnection.getHeaderFieldKey(i); $hapSrS  
if(sHeader!=null) l0f6Lxfz  
{ $I%]jAh6  
if(sHeader.equals("Content-Length")) .*{LPfD|  
{ H{If\B%1t  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3ly|y{M",  
break; 191)JWfa  
} .'M]cN~  
} a>6p])Wh  
else !xSGZ D=AD  
break; n&^Rs )%v  
} MG|NH0k  
} Bb6_['y  
catch(IOException e){e.printStackTrace ();} 2_p/1Rs  
catch(Exception e){e.printStackTrace ();} "#%T*c{Tf0  
D KOdqTW  
}N NyUwFa  
Utility.log(nFileLength); tQ"PCm  
F/h)azcn  
Z q)A"'Y  
return nFileLength; Bs*s8}6  
} n$>H}#q  
O\?ei+(H7  
SrxX-Hir  
//保存下载信息(文件指针位置) sE% n=Ww  
private void write_nPos() _kfApO )O  
{ q%l<Hw6{z  
try{ a"EXR-+8  
output = new DataOutputStream(new FileOutputStream(tmpFile)); MWB?V?qPSC  
output.writeInt(nStartPos.length); {v(3[ 7  
for(int i=0;i<nStartPos.length;i++) % rkUy?=vu  
{ ouuj d~b+  
// output.writeLong(nPos); H3JWf MlW  
output.writeLong(fileSplitterFetch.nStartPos); RAvV[QkT  
output.writeLong(fileSplitterFetch.nEndPos); f-PDgs   
} 6xwC1V?:0t  
output.close(); }0I! n@  
} NW$Z}?I  
catch(IOException e){e.printStackTrace ();} &Ef'5  
catch(Exception e){e.printStackTrace ();} U<t Qj`  
} 0>vm&W<?)  
ke0Vy(3t{h  
zK}.Bhj#  
//读取保存的下载信息(文件指针位置) JP#m} W  
private void read_nPos() -<.>jX  
{ x~ I cSt  
try{ ?AR6+`0  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 4&tY5m>  
int nCount = input.readInt(); )<+Z,6  
nStartPos = new long[nCount]; K:y>wyzl  
nEndPos = new long[nCount]; )s M}BY  
for(int i=0;i<nStartPos.length;i++) xf|=n  
{ 3oj30L.  
nStartPos = input.readLong(); HG3jmI+u>  
nEndPos = input.readLong(); >%{h_5  
} s f%=q$z  
input.close(); K-K+%U  
} %k"-rmW  
catch(IOException e){e.printStackTrace ();} 6_XTeu  
catch(Exception e){e.printStackTrace ();} QJxcH$  
} ~*&_zPTN  
nRvV+F0#  
Upf1*$p  
private void processErrorCode(int nErrorCode) 3N?uY2  
{ #+XKfumLk  
System.err.println("Error Code : " + nErrorCode); f"/NY6  
} w$1.h'2  
8YCtU9D  
7:]I@Gc'  
//停止文件下载 u4%-e )$X  
public void siteStop() -)w/nq  
{ avdi9!J2  
bStop = true; rLp0VKPe  
for(int i=0;i<nStartPos.length;i++) B4|3@X0(  
fileSplitterFetch.splitterStop(); - iU7'  
nfd^'}$]  
Hc}(+wQN%  
} #;+GNF}0mG  
} Bdf3@sbM]  
//负责部分文件的抓取 NVP~`sxiZ  
**FileSplitterFetch.java 07n=H~yU  
*/ W Qe>1   
package NetFox; =VDN9-/.  
pDW .Pav  
VF;%Z  
import java.io.*; =>&d[G[m!  
import java.net.*; L,n'G%  
p=p,sJ/@  
th !Gc  
public class FileSplitterFetch extends Thread { RE*;nSVFt  
wqJH  
VsFRG;:\U  
String sURL; //File URL 5'6Oan7dL:  
long nStartPos; //File Snippet Start Position +YXyfTa  
long nEndPos; //File Snippet End Position 2: fSn&*/>  
int nThreadID; //Thread's ID (T,ST3{*k  
boolean bDownOver = false; //Downing is over IU&n!5d$)|  
boolean bStop = false; //Stop identical (.Sj"6+  
FileAccessI fileAccessI = null; //File Access interface .7{,u1N'  
+hi!=^b]  
hCM+=]z"  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException J-b Z`)[Q  
{ OF!(BJ L  
this.sURL = sURL; }{HlY?S  
this.nStartPos = nStart; e_7a9:2e  
this.nEndPos = nEnd; Ymx/N+Jl  
nThreadID = id; *&!&Y*Jzg  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 T2GJoJ!  
} U",kAQY  
{o AJL  
CPAizS  
public void run() t '* L,  
{ ^k/@y@%  
while(nStartPos < nEndPos && !bStop) dCN4aY[d  
{ kowBB0  
G8 H=xr#  
</Ja@%  
try{ |G } qY5_  
URL url = new URL(sURL); 5Q =o.wf  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); |}=xA%)  
httpConnection.setRequestProperty("User-Agent","NetFox"); bt"*@NJ$  
String sProperty = "bytes="+nStartPos+"-"; \K55|3~R  
httpConnection.setRequestProperty("RANGE",sProperty); Xbe=_9l&p  
Utility.log(sProperty); Sw%^&*J  
/GqW1tcO  
+uLl3(ml  
InputStream input = httpConnection.getInputStream(); p{NVJ^! +  
//logResponseHead(httpConnection); sBt,y _LW  
-6@#Nq_iWU  
\'x. DVp  
byte[] b = new byte[1024]; ;X*I,g.+H  
int nRead; :.J Ad$>P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Gg8F>y<[R  
{ l*^c?lp)  
nStartPos += fileAccessI.write(b,0,nRead); u8 Q`la  
//if(nThreadID == 1) M:rE^El  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); &( aw  
} .7_<0&kW  
3vepJ) D (  
SN' j?-  
Utility.log("Thread " + nThreadID + " is over!"); D.su^m_1  
bDownOver = true; R0HzNk  
//nPos = fileAccessI.write (b,0,nRead); )T&ZiHIJ3  
} gd#+N]C_  
catch(Exception e){e.printStackTrace ();} @T)kqT  
} dv1Y2[  
} bdbTK8-  
jI[Y< (F ;  
=*>ri  
//打印回应的头信息 ) G a5c  
public void logResponseHead(HttpURLConnection con) 5bBY[qp  
{ epXvk &  
for(int i=1;;i++) 5L!EqB>m;  
{ %=e^MN1  
String header=con.getHeaderFieldKey(i); O4t0 VL$  
if(header!=null) 7wKT:~~oS3  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); VN]70LFz*i  
Utility.log(header+" : "+con.getHeaderField(header)); > &tmdE  
else 8Mg wXH  
break; SI\ O>a 9{  
} <5BNcl\ZL  
} > >%m,F[  
'A2^K5`3  
J;wDvt]]1  
public void splitterStop() M-7^\wXTA  
{ !-B$WAV  
bStop = true; B:oE&Ahh{  
} r^zra|]  
;iq H:wO  
{0?^$R8j  
} \3q Z0  
a!guZUg6  
jJbS{1z  
/* &Zy%Zz  
**FileAccess.java rJtpTV@.  
*//文件访问(定位,写) s`#g<_{X  
package NetFox; jEu-CU#:  
import java.io.*; o&-D[|E|  
pm` f? Py  
T]oVNy  
public class FileAccessI implements Serializable{ ;T hn C>U  
B5v5D[ o5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 @5}(Y( @  
RandomAccessFile oSavedFile; rUn1*KWbE  
long nPos; :yxP3e%rp  
5LaF'>1yY  
OJ?U."Lxm$  
public FileAccessI() throws IOException N.'-9hv  
{ LiyR,e  
this("",0); ?LSwJ @#  
} jEMnre3/  
;suY  
q8 SHFKE  
public FileAccessI(String sName,long nPos) throws IOException \$+#7( K  
{ _*w kTI+j  
oSavedFile = new RandomAccessFile(sName,"rw"); /`s{!t#Y  
this.nPos = nPos; b]5/IT)@O  
oSavedFile.seek(nPos); Mh "iyDGA  
} <H,E1kGw9  
bUU\bc  
k|4}Do%;  
public synchronized int write(byte[] b,int nStart,int nLen) }y>/#]X  
{ yU|=)p5  
int n = -1; fL(_V/p^  
try{ Q3<ctd\]Y  
oSavedFile.write(b,nStart,nLen); l3N '@GO  
n = nLen; 'r'+$D7  
} Rt.2]eZEJ  
catch(IOException e) d~qZ;uw  
{ \)M EM=U  
e.printStackTrace (); 6DVHJ+WTV  
} ?G>E[!8ev  
;q?WU>c{?  
F]GX;<`  
return n; Ve\.7s  
} BN1,R] *;  
+?'a2pUS  
dnzZ\t>U  
} TUN6`/"  
O[+\` 63F=  
R+# g_"1@p  
/* +!/pzoWpE  
**SiteInfoBean.java BD2Gv)?g  
*/ d1}cXSQ1T  
package NetFox; @Zzg^1Ilpu  
"Wg5eML 0  
-&h<t/U  
public class SiteInfoBean { /lLG|aAe  
&SMM<^P.  
$Zn>W@\  
private String sSiteURL; //Site's URL nmw#4yHYy:  
private String sFilePath; //Saved File's Path 7V%b!R}  
private String sFileName; //Saved File's Name <YAs0  
private int nSplitter; //Count of Splited Downloading File a\m0X@Q  
^!6T,7 B B  
)O,+'w?  
public SiteInfoBean() yRWZ/,9x   
{//nSplitter的缺省值为5 1}q(Pn2  
//default value of nSplitter is 5 iw^"?:'%  
this("","","",5); E?h'OR@_ L  
} 5Z>+NKQ  
ZMEYF!j N  
,8.zbr  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ({<qs}H"  
{ | MXRNA~  
sSiteURL= sURL; UYH&x:WEd  
sFilePath = sPath; o4H'  
sFileName = sName; ._p^0UxT  
this.nSplitter = nSpiltter; 9gFfbvd  
5Z_aN|Xn  
_N"c,P0  
} Q"k #eEA  
_| >bOI  
i\zN1T_  
public String getSSiteURL() MZt&HbD-  
{ a?X #G/)  
return sSiteURL; :0% $u>;O:  
} vv1W<X0e<  
@4wN-T+1  
$aY:Z_s  
public void setSSiteURL(String value) DfZ)gqp/Av  
{ \|7Y"WEQ  
sSiteURL = value; pnGDM)H7  
} Y'?{yx{  
K7},X01^  
ub-vtRpm  
public String getSFilePath() *#Iqz9X.Y3  
{ ug?#Oa  
return sFilePath; ^,#MfF6  
} "|GX%> /  
m88[(l  
pAH 9  
public void setSFilePath(String value) @rlL'|&X*  
{ \GCT3$  
sFilePath = value; 72sBx3 ;  
} t+aE*Q  
X?S LYm@v  
J5zu}U?  
public String getSFileName() "v+%F  
{ p><DA fB  
return sFileName; `l-R?C?*!  
} xeSv+I-b  
q;<Q-jr&O  
~2}^ -,  
public void setSFileName(String value) 2(>=@q.1H  
{ eB5<N?;s  
sFileName = value; tVHQ$jJY%  
} zf A"xD  
IWnyqt(k  
+||[H)qym  
public int getNSplitter() J Sms \  
{ 2KSt4oa  
return nSplitter; s/OXZ<C|  
} u`wT_?%w  
C44*qiG.  
z1LY|8$G  
public void setNSplitter(int nCount) 7J$Yd976  
{ '?b.t2  
nSplitter = nCount; 8zH/a   
} UpqDGd7M  
} }\d3   
$F~hL?"?  
Ffr6P }I  
/* aR0v qRF  
**Utility.java )}SiM{g  
*/ 3L%g2`  
package NetFox; Eq'oy~.oV  
!Nno@S P@  
hP=z<&zb/  
public class Utility { (N$$N:ac[t  
{-,^3PI\  
-0:B2B  
public Utility() hionR)R4  
{ Xj;5i Vq  
Ge4 tc  
+( V+XT  
} R,ddH[3  
q pFzK  
//线程睡眠 P8;f^3V(+/  
public static void sleep(int nSecond) Mta;6<  
{ {bPcr hB  
try{ &Qq4xn+J  
Thread.sleep(nSecond); dIDs~  
} T(6B,  
catch(Exception e) 8Zvh"Z?  
{ t+B L O<  
e.printStackTrace (); -g)*v<Fb5  
} IP+1 :M  
} x_|:3I  
0 ;ov^]  
//日志 ?u8 vK<2h  
public static void log(String sMsg) 1Qgd^o:d  
{ 0-w^y<\  
System.err.println(sMsg); ^Sz?c_<2P  
} d 3 }'J  
od~`q4p1(-  
js8\"  
public static void log(int sMsg) 7<c&)No;  
{ S~4HFNe^&  
System.err.println(sMsg); i*%2 e)  
} <jRs/?1R  
} Gq r(.  
]qk/V:H:  
44kb  
/* P1m PC  
**TestMethod.java _G5M Q%z  
*/ yy-\$<j  
package NetFox; zVs|go>F  
aXefi'!6  
QZ54Osdl  
public class TestMethod { y i/jZX  
yD!V;?EnK  
J#y?^Qm$)<  
public TestMethod() ps6c>AN`A&  
{ ///xx/weblogic60b2_win.exe "Z6:d"S`  
try{ `?L-{VtM3*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $MG. I[h  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); `;R|SyrX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); id.W"5+  
fileFetch.start(); y3!=0uPf  
} D?_#6i;DJ  
catch(Exception e){e.printStackTrace ();} g$ *V A} s  
zorTZ #5  
/< CjBW:  
} q>q@ztt  
xbA% 'p  
o s HE4x  
public static void main(String[] args) {G%!M+n<  
{ 4GRmo"S  
new TestMethod(); ~f2zMTI|  
} gaJIc^O  
} M('cG  
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