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http断点续传简单实现(java)

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/* s57N) 0kP  
**SiteFileFetch.java vgn@d,v  
*/ z s Qo$p  
package NetFox; 6{x,*[v  
import java.io.*; gw+9x<e  
import java.net.*; H-rWDN#  
d-bqL:/  
s"=6{EVqk3  
public class SiteFileFetch extends Thread { =U OLT>!  
AJt!!crs  
RVtQ20e";r  
SiteInfoBean siteInfoBean = null; //文件信息Bean Nd:R" p*8  
long[] nStartPos; //开始位置  R7oj#  
long[] nEndPos; //结束位置 50j OA#l[  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 K*K1(_x=  
long nFileLength; //文件长度 ZZ/cq:3$P  
boolean bFirst = true; //是否第一次取文件 5OM?3M  
boolean bStop = false; //停止标志 >YW\~T  
File tmpFile; //文件下载的临时信息 mIZwAKo  
DataOutputStream output; //输出到文件的输出流 Q^}%c U0  
~>G]_H]?  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) O(2cWQ  
public SiteFileFetch(SiteInfoBean bean) throws IOException NX* O_/  
{ kg5ev8  
siteInfoBean = bean; {!ZyCi19  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); *E>.)B i  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ske@uzAz  
if(tmpFile.exists ()) B,$l4m4  
{ KcGsMPJ  
bFirst = false; hPm>tV2X  
read_nPos(); /%x7+Rl\-^  
} KV!<Oq  
else "vF MSY  
{ noVa=aU^  
nStartPos = new long[bean.getNSplitter()]; Y,z??bm~J  
nEndPos = new long[bean.getNSplitter()]; H(u+#PIIw  
} hP?fMW$V  
'E;W  
l?N`{ ,1^  
q?{}3 dPC  
} ]o.vB}WsY  
u/^|XOy  
V*n==Nb5L  
public void run() Go\VfLLw  
{ M.%shrJ/  
//获得文件长度 _"f  :`  
//分割文件 J}g~uW  
//实例FileSplitterFetch "Tbnxx]J  
//启动FileSplitterFetch线程 9V!-ZG  
//等待子线程返回 Z_z#QX>=D  
try{ j\)H  
if(bFirst) '8Wv.X0`  
{ Fxd{ Zk`  
nFileLength = getFileSize(); D!> d0k,Y  
if(nFileLength == -1) IhonnLLW  
{ 4I~i)EKy6  
System.err.println("File Length is not known!"); =G>(~+EA  
} 9BON.` |_  
else if(nFileLength == -2) D&{ *AH%Q  
{ %]4-{%v  
System.err.println("File is not access!"); QXQ  
} 7[o {9Yp&  
else *Zkss   
{ (aKZ5>>cN  
for(int i=0;i<nStartPos.length;i++) ?ApRJm:T  
{ X , ZeD  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Vewzo1G2  
} R2^iSl%pj  
for(int i=0;i<nEndPos.length-1;i++) pCt}66k}  
{ 981!2*  
nEndPos = nStartPos[i+1]; tV`&- H  
} hZuYdV{'h  
nEndPos[nEndPos.length-1] = nFileLength; f=ib9WbR#  
} 5u,sx664  
} xH$%5@~  
dF,DiRD  
< l[` "0  
//启动子线程 FmA-OqEpA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; k,]{NO   
for(int i=0;i<nStartPos.length;i++) v MWC(m  
{ ?UK:sF| (O  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), MZ^Ch   
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), P1QB`&8F  
nStartPos,nEndPos,i); Qa?Q bHc  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); rqC1  
fileSplitterFetch.start(); M,{<TpCx  
} N7B}O*;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), s}!"a8hU`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); DZAH"sb  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", WFdem/\kX  
nEndPos = " + nFileLength); 2V<# Y  
// fileSplitterFetch[nPos.length-1].start(); h>Rpb#]  
!L$oAqW  
CU !.!cZ{  
//等待子线程结束 ~$ WQ"~z  
//int count = 0; 8)`5P\  
//是否结束while循环 _ ^3@PM>  
boolean breakWhile = false; ]eL~L_[G\  
^ N_`^m  
h=mv9=x  
while(!bStop) @f'AWeJ2  
{ OAyE/Q|  
write_nPos(); JgZdS-~  
Utility.sleep(500); Ua!Odju*w  
breakWhile = true; Ot"(uW4$[  
"lb\c  
,dq`EsHg`M  
for(int i=0;i<nStartPos.length;i++) LQ|<3]  
{ 7dx4~dF  
if(!fileSplitterFetch.bDownOver) '.xkn{c  
{ 1r&AB!Z #  
breakWhile = false; s-o~@(r6  
break; )%1&/uN)  
}  pe|\'<>i  
} CTh1;U20  
if(breakWhile) t"FRLC  
break; 3pzOt&T|w  
F .& *D~f  
,7/\&X<`B  
//count++; 7{8)ykBU^  
//if(count>4) ]dQZ8yVK  
// siteStop(); SwQOFE/Dv~  
} f61]`@Bk  
$Jt8d|UP  
(rMTW+,  
System.err.println("文件下载结束!"); 96k(X LR  
} iNMLYYq]l  
catch(Exception e){e.printStackTrace ();} VdYOm  
} g8B&u u #  
FxMMxY,*%  
` C/fF_YA  
//获得文件长度 d u _O}x  
public long getFileSize() _LLW{^V  
{ ',<{X (#(  
int nFileLength = -1; VN1# 8{  
try{ E%KC'T N^D  
URL url = new URL(siteInfoBean.getSSiteURL()); UX+?0K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6!i( \Q*  
httpConnection.setRequestProperty("User-Agent","NetFox"); |2tSUOZ  
&FT5w T  
zV9 =  
int responseCode=httpConnection.getResponseCode(); pvK \fSr  
if(responseCode>=400) V/+H_=|  
{ &n,xGIG  
processErrorCode(responseCode); 9G=A)j  
return -2; //-2 represent access is error eU<]h>2  
} fLf#2EA  
KI^q 5D ?  
jKe$&.q@  
String sHeader; R A-^!4tX  
#h}IUR  
>c~9wv  
for(int i=1;;i++) $u(M 4(}  
{ F=P+;%.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :K a^  
//Utility.log(in.readLine()); W\ZV0T;<]  
sHeader=httpConnection.getHeaderFieldKey(i); Lcm~QF7cd  
if(sHeader!=null) 7cJO)cm0'  
{ m7bn%j-{$f  
if(sHeader.equals("Content-Length")) loAfFK>g  
{ A@fshWrl%  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?}!gLp  
break; D~t"9Z\  
} @p?b"?QaB  
} 1VPfa  
else S:"z<O  
break; tOp:e KN  
} >*ha#PE  
} "m<eHz]D  
catch(IOException e){e.printStackTrace ();} Xv<;[vq}F  
catch(Exception e){e.printStackTrace ();} DT1i2!  
X8NO;w@z#  
UGezo3}  
Utility.log(nFileLength); -O5(%  
/I`!i K  
3z{5c   
return nFileLength; n8y,{|  
} P*nT\B  
NC[GtAPD3  
9cx!N,R t  
//保存下载信息(文件指针位置) )e <! =S  
private void write_nPos() b*F :l#  
{ dcc%G7w  
try{ C$Hl`>?$  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +p%5/ smfs  
output.writeInt(nStartPos.length); (Mire%$h  
for(int i=0;i<nStartPos.length;i++) IJb1) ZuR  
{ + X|m>9  
// output.writeLong(nPos); 6=`m   
output.writeLong(fileSplitterFetch.nStartPos); ]R3pBC"Jv  
output.writeLong(fileSplitterFetch.nEndPos);  el*pYI  
} }G:uzud10  
output.close(); M}KM]<  
} \w@_(4")Qb  
catch(IOException e){e.printStackTrace ();} \Z7([Gh  
catch(Exception e){e.printStackTrace ();} q4#f *]  
} b&V]|Z (  
,oi`BOh  
\i;~~;D  
//读取保存的下载信息(文件指针位置) lXL7q?,9  
private void read_nPos() TF iM[  
{ {dr&46$p  
try{ <:yq~?  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); .8uwg@yD  
int nCount = input.readInt(); 9'*ZEl^?D  
nStartPos = new long[nCount]; l!2Z`D_MD  
nEndPos = new long[nCount]; F~rY jAFTi  
for(int i=0;i<nStartPos.length;i++) xvz5\s|b  
{ aSj1P/A  
nStartPos = input.readLong(); D A)0Y_  
nEndPos = input.readLong(); Hk~ gcG  
} CTrs\G  
input.close(); K7R])*B.~  
} H6 f; BS  
catch(IOException e){e.printStackTrace ();}  _I}L$  
catch(Exception e){e.printStackTrace ();} m-KK {{  
} : R*^Izs=  
{ `|YX_HS  
&)f++(i  
private void processErrorCode(int nErrorCode) {'Qk>G s  
{ P+%)0*W  
System.err.println("Error Code : " + nErrorCode); mP .&fS  
} { )GEgC  
eYX_V6c  
JE:n`l/p  
//停止文件下载  yLIj4bf  
public void siteStop() T _9ZI|Jx  
{ f;XsShxr  
bStop = true; ;gu>;_  
for(int i=0;i<nStartPos.length;i++) 0}7Rm>  
fileSplitterFetch.splitterStop(); ci NTYow  
xS-nO_t 'E  
GTIfrqT  
} ~aR='\<  
} ].T;x|  
//负责部分文件的抓取 yc4f\0B/  
**FileSplitterFetch.java h/bYtE  
*/ Cy> +j{%!  
package NetFox; >,]e[/p  
VGUDUM.8  
@DC2ci >  
import java.io.*; e%0#"6}  
import java.net.*; Iybpk?,M+  
1~u\]Zi=D  
-V_S4|>   
public class FileSplitterFetch extends Thread { W9m[>-Ew  
N4(VRA  
*>*/|  
String sURL; //File URL 1Kf t?g  
long nStartPos; //File Snippet Start Position Y},GZ^zqy  
long nEndPos; //File Snippet End Position bme#G{[)Y  
int nThreadID; //Thread's ID QM=436fq  
boolean bDownOver = false; //Downing is over *_rGBW  
boolean bStop = false; //Stop identical R.'Gg  
FileAccessI fileAccessI = null; //File Access interface %=O!K>^vt<  
0bL=l0N$W  
uqeWdj*Y  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]BD5+>;  
{ E_uH' E  
this.sURL = sURL; 4xn^`xf9  
this.nStartPos = nStart; aNU%OeQA  
this.nEndPos = nEnd; A8/4:>Is  
nThreadID = id; F(fr,m3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Tka="eyIj3  
} Ijro;rsEKM  
zV Li  
kV9NFo22  
public void run() < io8 b|A  
{ x&b-Na3Xi  
while(nStartPos < nEndPos && !bStop) OWfj<#}t+  
{ |i}g7  
19`0)pzZ*P  
k6XmBBIj-  
try{ (\Zo"x;(  
URL url = new URL(sURL); *n ?:)(  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); boB{Y7gO4  
httpConnection.setRequestProperty("User-Agent","NetFox"); leJd) {  
String sProperty = "bytes="+nStartPos+"-"; $gK>R5^G>  
httpConnection.setRequestProperty("RANGE",sProperty); 'E8Qi'g  
Utility.log(sProperty); bdhgHjz  
SP1oBR"3  
v!C+W$,T  
InputStream input = httpConnection.getInputStream(); hd%F7D5  
//logResponseHead(httpConnection); 6RodnQ  
^TK)_wx  
DTVnQC  
byte[] b = new byte[1024]; ~,7R*71  
int nRead; hIr^"kVK  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <u/({SZ&  
{ bvTkS EN  
nStartPos += fileAccessI.write(b,0,nRead); M)Q+_c2*  
//if(nThreadID == 1) # TF  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); YHAg4 eb8  
} \ .s".aA  
 ?C\9lLX  
G dY^}TJrh  
Utility.log("Thread " + nThreadID + " is over!"); n K=V`  
bDownOver = true; &>t1A5  
//nPos = fileAccessI.write (b,0,nRead); ~h+3WuOv  
} n8,/olqwW  
catch(Exception e){e.printStackTrace ();} &p/k VM  
} .1}(Bywm5  
} &|*|  
{4*%\?c,n  
=Ybu_>  
//打印回应的头信息 \ziF(xTvqG  
public void logResponseHead(HttpURLConnection con) m!(K  
{ CB)#; |aDB  
for(int i=1;;i++) 4ebGAg?_  
{ c?S402M}  
String header=con.getHeaderFieldKey(i); sBL^NDqa2  
if(header!=null) aH~"hB^e  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); _Z&R'`kg  
Utility.log(header+" : "+con.getHeaderField(header)); |JQ05nb  
else %Kp}Wo6  
break; T94$}- 5/)  
} TH VF@@q  
} Gx)D~7lz  
SYx)!n6U  
0g\&3EvD  
public void splitterStop() =c'LG   
{ 'Ud5;?{  
bStop = true; ]W,g>91m  
} ~gD]JiiA  
!5-[kG&  
k=[R o  
} !$HWUxM;p  
MiRB*eA  
KNhH4K2iP8  
/* EzaOg|  
**FileAccess.java RZjR d  
*//文件访问(定位,写) Xs/hqIXB  
package NetFox; sYzG_* )  
import java.io.*; oCS NA.z  
.wywO|  
{JJ`|*H$_  
public class FileAccessI implements Serializable{ =k z;CS+  
Oc>-jhx?  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 y:L|]p}huE  
RandomAccessFile oSavedFile; RWE%? `   
long nPos; Yu=^`I  
%oo&M;  
]F~5l?4u#  
public FileAccessI() throws IOException EMo6$(  
{ -h}J%UV  
this("",0); 6dh PqL  
} FYJB.lAT  
t j0vB]c  
lMP7o&  
public FileAccessI(String sName,long nPos) throws IOException HFazqQ[  
{ $W2AiE[Wm  
oSavedFile = new RandomAccessFile(sName,"rw"); C+Z"0\{o  
this.nPos = nPos; gM8eO-d  
oSavedFile.seek(nPos); VF-d^AGt  
} 1NTe@r!y  
^iTA4 0K  
M\%{!Wzo8  
public synchronized int write(byte[] b,int nStart,int nLen) R[(,wY_1  
{ ) E\pQ5&  
int n = -1; :A$6Y*s\  
try{ B.|vmq,u  
oSavedFile.write(b,nStart,nLen); qhtc?A/0}  
n = nLen; 1L0ku@%t9Y  
} MG6Tk(3S  
catch(IOException e) hug12Cu  
{ gOkO8P6P8  
e.printStackTrace (); V6L_aee}CK  
} 5^xt/vYa)  
!\m.&lk'^  
h\5 7t@A  
return n; UaBR;v-.B3  
} ;9~z_orNQZ  
`XnFc*L 1  
U{x'@/Ld  
} H\^^p!^)  
 u32<=Q[  
bY<"$);s  
/* )sQbDA|p  
**SiteInfoBean.java > + SEze  
*/ o^ 4+eE  
package NetFox; H\S,^)drJ?  
iPIA&)x}  
BK +JHT  
public class SiteInfoBean { L/ZZe5I  
]u:NE'0Xy  
WRgz]=W3w  
private String sSiteURL; //Site's URL u,C-U!A  
private String sFilePath; //Saved File's Path 1~*_H_Q't  
private String sFileName; //Saved File's Name 1{wy%|H\  
private int nSplitter; //Count of Splited Downloading File %6n;B|!  
`XD$1>  
;8A_- $  
public SiteInfoBean() >8VJ!Kg4  
{//nSplitter的缺省值为5 <Z5prunov  
//default value of nSplitter is 5  LKm5U6  
this("","","",5); 9> |rIw  
} ^'h~#7s  
*D'V W{  
7}*5Mir p  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) j04Q3d \f  
{ UeRenp  
sSiteURL= sURL; HqbTJ!a  
sFilePath = sPath; QW!'A`*x  
sFileName = sName; WgIVhj  
this.nSplitter = nSpiltter; qjWgyhL  
u66w('2  
J:>TV.TP  
} mMMu'N  
5pDxFs=v  
bi5'-.B  
public String getSSiteURL() >):b AfI  
{ l"- D@]"  
return sSiteURL; n;MoMGnPh,  
} iU3co|q7  
GY!&H"%  
{S}/LSNB  
public void setSSiteURL(String value) -uh/W=Q1R  
{ LvR=uD  
sSiteURL = value; snK/,lm.  
} 0 cQf_o  
mr;WxxO5  
0}ZuF.  
public String getSFilePath() cO <x:{`  
{ Fb_~{q  
return sFilePath; <sPB|5Ak  
} I5e!vCG)  
Mn=_lhW K  
fN&O `T>  
public void setSFilePath(String value) /qz( ra  
{ `0so)2ty+  
sFilePath = value; s^AYPmR6  
} {!,+C0  
0D\FFfs  
u-?&~WA  
public String getSFileName() >s{[d$  
{  l[ L{m7  
return sFileName; "z qt'b0bW  
} `aC#s3[  
VA]%i P,O-  
kt@+UK."  
public void setSFileName(String value) Q8P;AN_JS  
{ $k!t&G  
sFileName = value; 3Y=S^*ztd  
} YX~H!6l  
Wima=xYe\5  
v"s}7trWV  
public int getNSplitter()  u2DsjaL  
{ \Q#F&q0  
return nSplitter; {}.c.W+  
} 8`im4.~#%  
7`P(LQAr!  
]-0 &[@I4@  
public void setNSplitter(int nCount) C[[z3tn  
{ O ~"^\]\  
nSplitter = nCount; l lQ<x  
} 8sL7p4  
} pa.W-qyu  
'vh:(-  
(g   
/*  Z3I<  
**Utility.java uD+;5S]us  
*/ }+u<^7$g|  
package NetFox; lfCoL@$6D  
DTJ~.  
ov?>ALRg  
public class Utility { &gq\e^0CRZ  
$ biCm$a  
inp=-  
public Utility() hLBX,r)u  
{ &oAuh?kTq  
d,$[633It}  
[t0gXdU 6  
} @O4m-Oosi  
^d!-IL_  
//线程睡眠 398%16}  
public static void sleep(int nSecond) &ts!D!Hj  
{ ZY {,//  
try{ 8p PAEf  
Thread.sleep(nSecond); iS02uVmBZ  
} d]+g3oy `  
catch(Exception e) TlM ]d;9G  
{ ]x~H"<V  
e.printStackTrace (); eoow]me  
} In]h+tG?rN  
} +8v!vuO'  
Rg' 1 F  
//日志 *-g S u  
public static void log(String sMsg) Ib]{rmaP  
{ <Y9ps`{}:  
System.err.println(sMsg); ;c~6^s`2  
} z%]~^k8  
HHT K{X+  
0hCJovSG%  
public static void log(int sMsg) \O@,v0?R  
{ ba|~B8rII[  
System.err.println(sMsg); mM>{^%2Q:  
} hO\_RhsRy?  
} iv\?TAZC  
NNSn]LP  
1vi<@i,  
/* IL`5RZi1  
**TestMethod.java _ 4pBJOJQ6  
*/ S+_}=25  
package NetFox; 6?z&G6  
_! \X>rfz  
N!aV~\E  
public class TestMethod { s +^YGB  
V/<dHOfR\  
Spt[b.4mF  
public TestMethod() zN*/G6>A  
{ ///xx/weblogic60b2_win.exe ;OE{&  
try{ Peh( *D{  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1u 'x|Un  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); V_(lZDjh*  
SiteFileFetch fileFetch = new SiteFileFetch(bean); qFt%{~a S  
fileFetch.start(); p%_r0  
} ,NPU0IDG>  
catch(Exception e){e.printStackTrace ();} ct fKxGH  
&KX|gB'  
ngn%"xYX  
} yUqvF6+26  
9^)ochY3  
ey@y?X=  
public static void main(String[] args) XBdC/DM[  
{ X Oc0j9Oa  
new TestMethod(); {FteQ@(  
} Y?R;Y:u3Z  
} `%"zq"1`0  
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