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http断点续传简单实现(java)

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/* bhmjH(.t  
**SiteFileFetch.java C#Jj;Gd  
*/ %vXQ Sz  
package NetFox; K="+2]{I  
import java.io.*; NSq=_8  
import java.net.*; U~m.I  
MF`'r#@:wa  
u i1m+  
public class SiteFileFetch extends Thread { Xhi?b|  
:X f3wP=  
BE~[%6T7  
SiteInfoBean siteInfoBean = null; //文件信息Bean `vw.~OBl  
long[] nStartPos; //开始位置 #F@7>hd1  
long[] nEndPos; //结束位置 M6iKl  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b G)MG0<TT  
long nFileLength; //文件长度 }b`*%141  
boolean bFirst = true; //是否第一次取文件 |xm|Q(PG  
boolean bStop = false; //停止标志 ;>N ~ ,Q  
File tmpFile; //文件下载的临时信息 z3]U% y(,  
DataOutputStream output; //输出到文件的输出流 639k&"V  
Mk[`HEO  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) YqgW8 EM  
public SiteFileFetch(SiteInfoBean bean) throws IOException /5Loj&!=  
{ <Tf;p8#  
siteInfoBean = bean; 7 w,FA  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); L ]c9  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); x3 |'jmg  
if(tmpFile.exists ()) DlI5} Jh  
{ mI#; pO2  
bFirst = false; ]6 wi  
read_nPos(); ?C35   
} T*yveo &j  
else sA}R!  
{ <h9\A&  
nStartPos = new long[bean.getNSplitter()]; !$Z"\v'b  
nEndPos = new long[bean.getNSplitter()]; \<**SSN  
} <J-Z;r(gQN  
-::%9D}P|  
CN(4;-so)  
46Nf|~  
}  HU9y{H  
(_ah~VnO  
~py0Vx,F  
public void run() '.,.F0{x  
{ xQap44KPZ  
//获得文件长度 u2-7vudh  
//分割文件 u(702S4  
//实例FileSplitterFetch gH3kX<e  
//启动FileSplitterFetch线程 L0tKIpk  
//等待子线程返回 Z;D3lbqE  
try{ S8m&Rj3O&  
if(bFirst) "~C#DZwt{  
{ D5u"4\g< &  
nFileLength = getFileSize(); #Ca's'j&f  
if(nFileLength == -1) (}1f]$V  
{ VAGMI+ -  
System.err.println("File Length is not known!"); 4tJ4X' U  
} _`>7 Q) ,7  
else if(nFileLength == -2) rJp6d :M  
{ ]bb}[#AY  
System.err.println("File is not access!"); /g'-*:a  
}  <z2mNq  
else F*VMS  
{ vp-7>Wj  
for(int i=0;i<nStartPos.length;i++) y$o=\:  
{ pVS2dwBqE  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^]&{"!  
} 9PK-r;2  
for(int i=0;i<nEndPos.length-1;i++) \/'n[3x  
{ 5C1Rub)  
nEndPos = nStartPos[i+1]; u 7Y< ~  
} 2-!Mao"^  
nEndPos[nEndPos.length-1] = nFileLength; &>.1%x@R  
} #l#[\6  
} q- (N Zno  
\N+Ta:U1P  
LoE(W|nj  
//启动子线程 <Cu?$  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; e-3pg?M  
for(int i=0;i<nStartPos.length;i++) lFGxW 5  
{ tkqBCKpDa  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), OG7v'vmY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w*%$ lhp!  
nStartPos,nEndPos,i); h\*rv5\M  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %L>nXj  
fileSplitterFetch.start(); ~PW}sN6ppG  
} iCRw}[[  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), '8kjTf#g<l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); |!5T+H{Sj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", #aY<J:Nx  
nEndPos = " + nFileLength); #r)1<}_e#  
// fileSplitterFetch[nPos.length-1].start(); cN}A rv  
jI`To%^ Y  
U4l*;od  
//等待子线程结束 PJ'lZu8?x  
//int count = 0; Bi :wP/>v  
//是否结束while循环 oEoJa:h  
boolean breakWhile = false; }9udo,RWu  
8pMZ~W;  
`W$0T;MPF  
while(!bStop) >ydb?  
{ [=ak>>8  
write_nPos(); 'ag6B(0Z  
Utility.sleep(500); |z.GSI_!)  
breakWhile = true; m4U+,|Fa  
^iRwwN=d  
R|J>8AL}BY  
for(int i=0;i<nStartPos.length;i++) V /9"Xmv75  
{ ro^6:w3O^  
if(!fileSplitterFetch.bDownOver) "Xk%3\{P  
{ +M O5'z  
breakWhile = false; roj04|  
break; p$1Rgm\  
} }42qMOi#w1  
} #C;zS9(]B  
if(breakWhile) ]n]uN~)9  
break; 7M#$: Fdb  
NQiecxvt=  
C:GHP$/}  
//count++; wQ=yY$VP  
//if(count>4)  ]RX tC*  
// siteStop(); g;#KBxE  
} 2C33;?M  
j)tC r Py  
^Ii  \vk  
System.err.println("文件下载结束!"); 5 (21gW9  
} X]pWvQ Q]  
catch(Exception e){e.printStackTrace ();} -8Jl4F ,  
} *- IlF]  
~? FrI  
+.(}u ,:8  
//获得文件长度 JdUz!=I  
public long getFileSize() B?lBO V4v4  
{ g3~~"`2  
int nFileLength = -1; :O'C:n<g  
try{ Uq]EJu  
URL url = new URL(siteInfoBean.getSSiteURL()); Fwx~ ~"I  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ZCE%38E N  
httpConnection.setRequestProperty("User-Agent","NetFox"); 5 2@udp  
nl-t<#z[  
Q_]!an(  
int responseCode=httpConnection.getResponseCode(); #S53u?JV8  
if(responseCode>=400) xngeV_xc2  
{ N{ V5 D  
processErrorCode(responseCode); bg1"v a#2  
return -2; //-2 represent access is error 1; Wkt9]9  
} ()nKug`.@  
N?=qEX|R  
?dKa;0\  
String sHeader; uO_,n  
eN| HJ=  
`b.o&t$L  
for(int i=1;;i++) %%+mWz a  
{ IglJEH[+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); H#|Z8^ *Ds  
//Utility.log(in.readLine()); wCU&Xb$F  
sHeader=httpConnection.getHeaderFieldKey(i); ),;D;LI{S  
if(sHeader!=null) TvWU[=4Yk  
{ Ku0H?qft(  
if(sHeader.equals("Content-Length")) .kbr?N,'  
{ 0/SC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *qO]v9 j  
break; i{|lsd(+  
} %uz|NRB=  
} dI_r:xN  
else W7TXI~7  
break; $h,&b<-  
} ;-9zMbte :  
} 8!uL-_Bn  
catch(IOException e){e.printStackTrace ();} T@Ss&eGT2  
catch(Exception e){e.printStackTrace ();} YHO;IQ5  
3b|7[7}&  
o%Uu.P  
Utility.log(nFileLength); L_Y9+ e  
)RA\kZ"  
jiwpDB&[  
return nFileLength; 9 wSl,B-  
} JtYYT/PB  
1!>bhH}{D  
.K|P&  
//保存下载信息(文件指针位置) om".j  
private void write_nPos() ` $.X[\*U  
{ Z]x  5!  
try{ :k ME  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Y)Znb;`?a  
output.writeInt(nStartPos.length); ){O1&|z-  
for(int i=0;i<nStartPos.length;i++) HUU >hq9  
{ Kf05<J!  
// output.writeLong(nPos); &*(n<5 wt  
output.writeLong(fileSplitterFetch.nStartPos); 2I]]WBW#:  
output.writeLong(fileSplitterFetch.nEndPos); rV8(ia  
} #$rf-E5g-K  
output.close(); 00`bL  
} kZU"Xn  
catch(IOException e){e.printStackTrace ();} rPiiC/T.`  
catch(Exception e){e.printStackTrace ();} YW8K $W  
} W>p\O9BG  
 /,1SE(  
hi;WFyJTu  
//读取保存的下载信息(文件指针位置) "xD}6(NL(r  
private void read_nPos() DL'd&;6  
{ |`_ <@b  
try{ i(M(OR/4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9,S,NvSq  
int nCount = input.readInt(); BGB,Gb  
nStartPos = new long[nCount]; xHEVR!&c4  
nEndPos = new long[nCount]; ~a'nHy1  
for(int i=0;i<nStartPos.length;i++) lq>*x=<  
{ e Z@Gu  
nStartPos = input.readLong(); 9nng}em>.  
nEndPos = input.readLong(); @D fkGm[%  
} vQ:x% =]  
input.close(); "C:rTIH  
} $"Y3mD}?L  
catch(IOException e){e.printStackTrace ();} \3%W_vU_  
catch(Exception e){e.printStackTrace ();} +Fk4{p  
} F3r S6_  
?@Z7O.u  
<KHv|)ak  
private void processErrorCode(int nErrorCode) #'J~Xk   
{ Qy{NS.T  
System.err.println("Error Code : " + nErrorCode); ?*CRa$_I|  
} sTd}cP  
&q4ox71  
Jq# [uX  
//停止文件下载 8_"3Yb`f  
public void siteStop() "NxOOLL  
{ J*}VV9H  
bStop = true; ijvNmn1k  
for(int i=0;i<nStartPos.length;i++) r@|R-Binz  
fileSplitterFetch.splitterStop(); T1lXYhAWS  
^D9 /  
i'M^ez)u  
} nHI(V-E2:H  
} `[X6#` <  
//负责部分文件的抓取 rU; g0'4e  
**FileSplitterFetch.java 8'3"uv  
*/ bHO7* E  
package NetFox; &[NVP&9&U  
pt=7~+r  
^Lsc`<xC  
import java.io.*; ~J%R-{U9  
import java.net.*; a;56k  
uAp -$?  
x HY+q ;  
public class FileSplitterFetch extends Thread { M{*kB2jr  
&@=u+)^-{  
TRSOO}  
String sURL; //File URL h^['rmd  
long nStartPos; //File Snippet Start Position '/Cg*o/  
long nEndPos; //File Snippet End Position (d54C(")  
int nThreadID; //Thread's ID HMF8;,<_w?  
boolean bDownOver = false; //Downing is over =8O}t+U  
boolean bStop = false; //Stop identical ov1Wr#s  
FileAccessI fileAccessI = null; //File Access interface La\Q'0  
/r>IV`n{  
UV?[d:\>'  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =ZG<BG_  
{ $=\d1%_R|  
this.sURL = sURL; grGhN q  
this.nStartPos = nStart; `f%&<,i  
this.nEndPos = nEnd; ?x:m;z/  
nThreadID = id; d?JAUbqy  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 {V.Wk  
} Z/xV\Ggx  
IS-}:~Pi  
7Aqn[1{_O  
public void run() s;s0}Td_1  
{ )r=9]0=  
while(nStartPos < nEndPos && !bStop) "P MO  
{ :b"= KQ  
M#ZT2~+CT  
:eSc;  
try{ Pl_^nFm0  
URL url = new URL(sURL); |B 9t-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); y*w"J3|29  
httpConnection.setRequestProperty("User-Agent","NetFox"); &xgZF Sq  
String sProperty = "bytes="+nStartPos+"-"; F@g17aa  
httpConnection.setRequestProperty("RANGE",sProperty); [C~fBf5  
Utility.log(sProperty); hl`u"?rg  
Xc{ZN1 4n  
Og +)J9#  
InputStream input = httpConnection.getInputStream(); bdCykG-  
//logResponseHead(httpConnection); x,w8r+~5  
w_\nB}_  
c2/"KT  
byte[] b = new byte[1024]; j]AekI4I  
int nRead; Z?-;.G*  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [9LxhPi  
{ 6Ux[,]G K  
nStartPos += fileAccessI.write(b,0,nRead); '[%jjUU  
//if(nThreadID == 1) ?qy*s3 j'M  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J l\'V  
} 3]N q@t  
wXz\NGW  
>A<Df  
Utility.log("Thread " + nThreadID + " is over!"); *E.LP1xP  
bDownOver = true;  +.=1^+a  
//nPos = fileAccessI.write (b,0,nRead); ;;M"hI3@  
} ]7*kWc2  
catch(Exception e){e.printStackTrace ();} ;3mL^  
} >8%M*-=p  
} Ha?G=X  
lHcA j{6  
C(}^fJ6r  
//打印回应的头信息 JT}.F!q6E  
public void logResponseHead(HttpURLConnection con) xg?auje  
{ }*h47t}  
for(int i=1;;i++) k j-=xhJ{=  
{ Mw+v"l&mU  
String header=con.getHeaderFieldKey(i); _FT6]I0  
if(header!=null) >d#3|;RY  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pKq]X}[^c  
Utility.log(header+" : "+con.getHeaderField(header)); 0Yp>+:#  
else KyjyjfIwH  
break; a%v>eXc  
} >[EBpYi  
} w#sq'vo4%  
V n^)  
Zd$JW=KR]l  
public void splitterStop() Z4#v~!  
{ oooS s&t  
bStop = true; },&h[\N{6  
} 9976H\{  
.8K6C]gw  
~JLYhA^'+<  
} #,TELzUVE  
76_<xUt{  
N\'TR6_,b  
/* Yc|uD-y  
**FileAccess.java 7_KXD#  
*//文件访问(定位,写) *U_S1>0n  
package NetFox; =PZWS& (L  
import java.io.*; UoHd-  
;I+H>$%jZ  
Yh$fQ:yi\&  
public class FileAccessI implements Serializable{ VtWT{y5Ec  
_W}(!TKO  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ^zg acn  
RandomAccessFile oSavedFile; ?,>5[Ha^?  
long nPos; S@Iw;V  
oPsK:GC`U  
NCn`}QP  
public FileAccessI() throws IOException "H$@b`)  
{ \ADLMj`F|  
this("",0); }3J=DCtS  
} []gRfM]$&  
2QL?]Vo  
\sITwPA[z  
public FileAccessI(String sName,long nPos) throws IOException t0.;nv@A0  
{ ]+ZM/'X  
oSavedFile = new RandomAccessFile(sName,"rw"); x9&p!&*&IT  
this.nPos = nPos; W+\?~L.  
oSavedFile.seek(nPos); `c9'0*-  
} M$H`^Pv  
cJ2PI  
n[P\*S  
public synchronized int write(byte[] b,int nStart,int nLen) 0<Q*7aY  
{ z&F5mp@  
int n = -1; +?Ez} BP  
try{ m8+:=0|$  
oSavedFile.write(b,nStart,nLen); 8SZK:VE@  
n = nLen; `;cz;"  
} :3O5ET'1  
catch(IOException e) KUFz:&wK  
{ G|*G9nQ  
e.printStackTrace (); 7&foEJ3q  
} xNIGO/uI~  
#A )Ab%r8"  
R5ZIC4p  
return n; -=mwy  
} VE$t%QT  
6@YH#{~Zpv  
zSXA=   
} Ha)np  
$w/E9EJ)3A  
mX;H((  
/* Cfv]VQQE  
**SiteInfoBean.java p/&HUQQk  
*/ P0 b4Hq3  
package NetFox; ({ k7#1 h8  
X}W)3v  
^1 ;BiQ  
public class SiteInfoBean { P,ydt  
^V .'^=l  
h/?6=D{  
private String sSiteURL; //Site's URL SY T$3|a  
private String sFilePath; //Saved File's Path ;MPKJS68@  
private String sFileName; //Saved File's Name 9go))&`PJL  
private int nSplitter; //Count of Splited Downloading File oj@g2H5P  
CmnHh~%  
F>-}*o  
public SiteInfoBean() `HyF_m>\  
{//nSplitter的缺省值为5 J^:n* C  
//default value of nSplitter is 5 M4:s;@qZ.  
this("","","",5); l!@ 1u^v2  
} (O0byu}  
p[qg&VKB  
9!#EwPD$#  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gr+Pl>C{  
{ M*`hDdS  
sSiteURL= sURL; 6 64q~_@B1  
sFilePath = sPath; 7n&yv9"  
sFileName = sName; p+Lv=e)0u  
this.nSplitter = nSpiltter; 2*'ciH37  
JD lBVZ!  
zJC EA  
}  KGT3|)QN  
x<F$aXOS  
5v|EAjB6o  
public String getSSiteURL() = F<:}Tx)C  
{ taDQ65  
return sSiteURL; gDC2 >nV  
} $.8 H>c  
C:j]43`  
Yt{&rPv,  
public void setSSiteURL(String value) Y;_T=  L  
{ -N# #w=  
sSiteURL = value; J\A8qh8  
} /b%Q[ Ck_  
I`^YAbnb  
}-nU3{1  
public String getSFilePath() H~Uq?!=b  
{ wOg,SMiq  
return sFilePath; +t"j-}xzE  
} g>n0z5&TNF  
A[JM4x   
iLtc HpN  
public void setSFilePath(String value) #jP/k.  
{ yU_9a[$V  
sFilePath = value; L~&" aF/b  
} ,LUTHWEo"I  
k|B2@{  
-oh7d$~  
public String getSFileName() 8xTix1u0  
{ m~>@BCn;  
return sFileName; 1;&T^Gdj  
} -J?~U2  
D=&K&6rr  
?,XC =}  
public void setSFileName(String value) 9@y3IiZ"}  
{ 6+PGwCS  
sFileName = value; %?=)!;[  
} LNiS`o\  
a.,_4;'UE1  
+)gB9DoK  
public int getNSplitter() [{cC  
{ HJ@5B"  
return nSplitter; m =k%,J_  
} v3-?CQb(  
I%xn,u  
Xw^X&Pp  
public void setNSplitter(int nCount) "&-C$J5 Id  
{ uvv.WbZ  
nSplitter = nCount; ,Rz }=j  
} t)r1"oA  
} D^$OCj\  
-9-fX(I  
'C~9]Y].  
/* j)L1H* S%  
**Utility.java /s`;9)G]9  
*/ j-32S!  
package NetFox; 6?o>{e7n^  
6mHhC?  
a D|Yo  
public class Utility { HcO5?{2  
7cw]v"iv  
KB+]eI-h  
public Utility() o](.368+4  
{ Euu ,mleM  
`%y5\!X  
SRf5W'4y  
} H\+-cvl  
* nCx[  
//线程睡眠 9L  HuS  
public static void sleep(int nSecond) eP= j.$  
{ tcOnM w  
try{ v}P!HczmMP  
Thread.sleep(nSecond); &t6Tcy  
} N-QCfDao  
catch(Exception e) `~nCbUUee  
{ =]b9X7}  
e.printStackTrace (); gZ`DT  
} `bqzg  
} |Fp'/~|w2d  
wd+O5Lr.R  
//日志 .bfST.OA  
public static void log(String sMsg) H,|YLKg-|  
{ ^PQM;"  
System.err.println(sMsg); or.\)(m#(  
} B_&^ER5j  
}Vl^EAR  
iZC`z }  
public static void log(int sMsg) 8\_*1h40s  
{ la`"$f  
System.err.println(sMsg); aAcKwCGq\  
} 7d9Z/J@>  
} (hsZ  
]]y[t|6  
PbN3;c3  
/* {AgBwBCE  
**TestMethod.java ^A#x<J+  
*/ !gJzg*{u@  
package NetFox; NWnWk  
U8[Qw}T P  
G?ZC 9w]rA  
public class TestMethod { `^%@b SE(  
Tk](eQsy.v  
3?^NN|xg  
public TestMethod() a7*COh  
{ ///xx/weblogic60b2_win.exe Z@oKz:U  
try{ t= *Jg/$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Hz?,#>{  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Bac|;+L~L  
SiteFileFetch fileFetch = new SiteFileFetch(bean); T 9MzUV&  
fileFetch.start(); UM\}aq=,  
} JZw^ W{  
catch(Exception e){e.printStackTrace ();} DaCblX  
[yF^IlSs  
:`5;nl63  
} |0]YA  
dk:xnX%  
$eMK{:$O  
public static void main(String[] args) eI?HwP{m  
{ 5p{25N_t  
new TestMethod(); N'a?wBBR  
} tvCcyD%w  
} -R8/`M8GbD  
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