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http断点续传简单实现(java)

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/* -&@[]/  
**SiteFileFetch.java 5N`g  
*/ |LiFX5!\  
package NetFox; s^js}9]p  
import java.io.*; |oPqX %?  
import java.net.*; 7q$9\RR5  
Ay"x<JB{U2  
;MNEe% TJ  
public class SiteFileFetch extends Thread { A7~)h}~   
1QjrL@$>15  
9CUMqaY2  
SiteInfoBean siteInfoBean = null; //文件信息Bean 8t0i j  
long[] nStartPos; //开始位置 rS)7D  
long[] nEndPos; //结束位置 ^EZ)NG=e5  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S7~yRIjB  
long nFileLength; //文件长度 E(8O3*=  
boolean bFirst = true; //是否第一次取文件 =]U[   
boolean bStop = false; //停止标志 V4/eGh_T  
File tmpFile; //文件下载的临时信息 gd#  
DataOutputStream output; //输出到文件的输出流 %Xkynso~  
|'Ve75 W6u  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) -V_e=Y<J/  
public SiteFileFetch(SiteInfoBean bean) throws IOException >L[,.}(9  
{ QF!K$?EU[  
siteInfoBean = bean; L$lo5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); zVkHDT[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); C Hyb{:<  
if(tmpFile.exists ()) bZ )3{  
{ )u3<lpoTy  
bFirst = false; q35%t61Lc  
read_nPos(); 5wP(/?sRy  
} kX5v!pm[  
else wz>j>e6k`  
{ khc5h^0  
nStartPos = new long[bean.getNSplitter()]; x\I9J4Q  
nEndPos = new long[bean.getNSplitter()]; h, +2Mc<  
} mY dU`j  
b>Vs5nY!  
_aa3Qw x  
BU]9eF!>h  
} @*A(#U8p3  
:%!=Ej.J  
)k0bP1oGS  
public void run() /HI#8  
{ dRas9g  
//获得文件长度 }[D[ZLv  
//分割文件 NVJvCs)3f  
//实例FileSplitterFetch 3U1xKF  
//启动FileSplitterFetch线程 ^9qncvV  
//等待子线程返回 |F9/7 z\5+  
try{ B@.U\.  
if(bFirst) [rE,fR   
{ l&;#`\s!V  
nFileLength = getFileSize(); z}u  
if(nFileLength == -1) qhLe[[>  
{ wyvs#T  
System.err.println("File Length is not known!"); 6i=m1Yk  
} ?%*Zgk!l7  
else if(nFileLength == -2) e,:@c3I  
{ {#Mz4s`M  
System.err.println("File is not access!"); l.>QO ;  
} \HTXl]  
else @i6D&e=  
{ .CwMxuW  
for(int i=0;i<nStartPos.length;i++) Ms^,]Q1{  
{ 3u+~!yz  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {jggiMwo.v  
} {IqbO>|"O_  
for(int i=0;i<nEndPos.length-1;i++) UAUo)VVi"  
{ )v0m7L v#/  
nEndPos = nStartPos[i+1]; A%%WPBk{O  
} rw8db'  
nEndPos[nEndPos.length-1] = nFileLength; oNl_r:G  
} wzP>Cq  
} SijC E~P  
:mY(d6#A>  
o)Ob}j  
//启动子线程 `Z/"Dd;F^3  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 1mf|:2,  
for(int i=0;i<nStartPos.length;i++) )CihqsA2  
{ [A[vR7&S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), nJA\P1@m  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )jCAfdnCs  
nStartPos,nEndPos,i); `6Y'H2WJ?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); "m/0>UU0  
fileSplitterFetch.start(); 9dSKlB5J  
} +}X@{DB  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 80axsU^H0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M0"xDvQ  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", -zG/@.  
nEndPos = " + nFileLength); {@B<$g   
// fileSplitterFetch[nPos.length-1].start(); 3mr9}P9;  
A!goR-J]  
`')3}  
//等待子线程结束 5I t+ S+a  
//int count = 0; (Cqhk:F  
//是否结束while循环 )[G5qTO  
boolean breakWhile = false; $+:_>n^#/  
.* V ZY  
.P-@ !Q5*  
while(!bStop) *.W ![%Be  
{ sq&$   
write_nPos(); 7lf* vqG  
Utility.sleep(500); b~%(5r.  
breakWhile = true;  8(5}Jo+  
]?b#~  
$6BXoh!  
for(int i=0;i<nStartPos.length;i++) H-^>Co_  
{ ks:Z=%o   
if(!fileSplitterFetch.bDownOver) m_' 1yX@  
{ AdR}{:ia  
breakWhile = false; BEifUgCh  
break; z/6eP`jj  
} O6l j^  
} V\X.AGc  
if(breakWhile) vYrqZie<  
break; d,+d8X  
>g8Tl`P,iN  
5A:b \  
//count++; 1Cp5a2{  
//if(count>4) n\wO[l)  
// siteStop(); Pou`PNvH  
} f{k2sU*uBE  
iS=} | 8"  
4CfPa6_  
System.err.println("文件下载结束!"); }(20MW8rMc  
} |V%Qp5 XJ  
catch(Exception e){e.printStackTrace ();} $(.[b][S  
} Y2QlK1.8V  
[p[Kpunr{l  
~48Uch\LG:  
//获得文件长度 |f?tyQ  
public long getFileSize() -~]*)&  
{ J=| fxR  
int nFileLength = -1; Da)9s %_4  
try{ &37QUdp+p  
URL url = new URL(siteInfoBean.getSSiteURL()); cZ%weQa#N)  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *d?,i -Q.+  
httpConnection.setRequestProperty("User-Agent","NetFox"); j01#Wq_\fk  
|*i0h`a  
GC~Tfrf=r  
int responseCode=httpConnection.getResponseCode(); $Rd74;edn  
if(responseCode>=400) *|a_(bQ4@  
{ -:AknQq  
processErrorCode(responseCode); a 0Hzf  
return -2; //-2 represent access is error pRc@0^G  
} $IUT5Gia`  
yzgDdAM  
kd9hz-*  
String sHeader; d7N}-nsB  
YeptYW@xfw  
_;L9&>!p6  
for(int i=1;;i++) i|)<#Ywl  
{ 9ZeTS~i  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~X*)gS-=  
//Utility.log(in.readLine()); '8}*erAg  
sHeader=httpConnection.getHeaderFieldKey(i); ja#E}`wC4  
if(sHeader!=null) W;eHDQ|  
{ 3?.3Z!H/  
if(sHeader.equals("Content-Length")) ' DCrSa>  
{ `N]!-=o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); u-f_,],p  
break; al(t-3`<  
} E[)`+:G]  
} Qf6Vj,~N  
else -c~nmPEG6  
break; {: T'2+OH>  
} gH(,>}{^K  
} @K3<K (  
catch(IOException e){e.printStackTrace ();} H YZ94[Ti  
catch(Exception e){e.printStackTrace ();}  (/-2bO  
/{."*jK  
9~SfZ,(  
Utility.log(nFileLength); A<ur20   
wFnIM2a,  
B|/=E470G  
return nFileLength; cX 9 !a,  
} 4 B"tz!  
p. SEW5  
&S>m +m'  
//保存下载信息(文件指针位置) V<ziJ7H/  
private void write_nPos() am]$`7R5d  
{ W}50E.\#  
try{ Ze~^+ EE  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Rjqeuyj:  
output.writeInt(nStartPos.length); jn&[=Y-  
for(int i=0;i<nStartPos.length;i++) '+hiCX-_  
{ kid3@  
// output.writeLong(nPos);  Cdin"  
output.writeLong(fileSplitterFetch.nStartPos); mg;+Th &  
output.writeLong(fileSplitterFetch.nEndPos); C{`+h163\  
} )[.FUx  
output.close(); $8kc1Q  
} )+'FTz` c  
catch(IOException e){e.printStackTrace ();} d OQU#5  
catch(Exception e){e.printStackTrace ();} U7bbJ>U_|  
} m}54yo  
/. k4Y  
d3v5^5kU  
//读取保存的下载信息(文件指针位置) \tc 4DS  
private void read_nPos() suC]  
{ _VLc1svv  
try{ )$p<BLU  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); MDZ,a 0?4t  
int nCount = input.readInt(); &^=6W3RD  
nStartPos = new long[nCount]; E:a_f!  
nEndPos = new long[nCount]; ,_,Z<X/  
for(int i=0;i<nStartPos.length;i++) T>7$<ulm  
{ $!h21  
nStartPos = input.readLong(); <7NY.zvwk]  
nEndPos = input.readLong(); ae`*0wbv  
} :P1 J>dcG  
input.close(); ] ?w hx &+  
} 8=Xy19<;t  
catch(IOException e){e.printStackTrace ();} s.d }*H-o  
catch(Exception e){e.printStackTrace ();} OSY$qL2  
} 'H+H4(  
/>=)=CGv;  
..`J-k  
private void processErrorCode(int nErrorCode) hK5BOq!y  
{ o?BcpWp  
System.err.println("Error Code : " + nErrorCode); :s`~m;Y9?  
} D[yOFJ~p)  
j qfxQ  
.Zv@iL5  
//停止文件下载 %C^U?m`  
public void siteStop() :Q@=;P2  
{ ZCsL%(  
bStop = true; f s_6`Xt  
for(int i=0;i<nStartPos.length;i++) gVO<W.?  
fileSplitterFetch.splitterStop(); 8h  
L 1iA ^ x  
R>f$*T  
} $9k7A 8K  
} 1Tz5tU9kR  
//负责部分文件的抓取 P(D0ru  
**FileSplitterFetch.java DC4O@"  
*/ _+7 3Y'  
package NetFox; Y7g^ ?6  
gmtp/?>e  
Jn!-Wa,  
import java.io.*; f86h"#4  
import java.net.*; \Jq$!foYx  
^x8*]Sz#x  
}q7rR:g  
public class FileSplitterFetch extends Thread { ;;#28nV  
//T1e7)  
fn(< <FA)  
String sURL; //File URL GvQKFgO6h  
long nStartPos; //File Snippet Start Position /Z`("X?_Kf  
long nEndPos; //File Snippet End Position wq+%O,  
int nThreadID; //Thread's ID gx,BF#8}  
boolean bDownOver = false; //Downing is over mhU ?N  
boolean bStop = false; //Stop identical #D4gNQg@R  
FileAccessI fileAccessI = null; //File Access interface {8`V5:  
D_mdX9-~  
U-!+Cxjs  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Zt;3HY=y  
{ l-4+{6lz  
this.sURL = sURL; fP<Tvf  
this.nStartPos = nStart; iG*@(  
this.nEndPos = nEnd; G>"=Af(t?Y  
nThreadID = id; ?XOl>IO  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0*G =~:  
} 6?GR+;/  
UolsF-U}'  
u By[x 0  
public void run() \[u7y. b  
{ cXP*?N4C f  
while(nStartPos < nEndPos && !bStop) t6m&+N  
{ {6}H}_( ]  
|Rk9W  
9C9>V]  
try{ 3Ov? kWFO  
URL url = new URL(sURL); Ne>yFl"u  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); !Q(xA,p  
httpConnection.setRequestProperty("User-Agent","NetFox"); CRXIVver  
String sProperty = "bytes="+nStartPos+"-"; N<XS-XB,  
httpConnection.setRequestProperty("RANGE",sProperty); )> >Tj7  
Utility.log(sProperty); BCUn[4Gp  
/~=W3lhY  
[H"\<"1o  
InputStream input = httpConnection.getInputStream(); LEu_RU?  
//logResponseHead(httpConnection); k/'>,WE  
dZ]['y%  
e0rh~@E  
byte[] b = new byte[1024]; Qy< ~{6V  
int nRead; ICq  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 9*`(*>S  
{ /XEt2,sI9  
nStartPos += fileAccessI.write(b,0,nRead); p@`]9tLP(K  
//if(nThreadID == 1) Zw4z`x1f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~\ uI&S5  
} R1A|g =kF  
z''ITX)oG  
m[l[yUw#  
Utility.log("Thread " + nThreadID + " is over!"); 8nKZ   
bDownOver = true; E+'P|~>oX  
//nPos = fileAccessI.write (b,0,nRead); F`C$F!GE  
}  Y7q=]  
catch(Exception e){e.printStackTrace ();} B}O M:0  
} Xx)PyO  
} b# v+_7  
e$ pXnMx7  
LHJ}I5zv  
//打印回应的头信息 i"4&UJu1;  
public void logResponseHead(HttpURLConnection con) CSu}_$wC#  
{ Obj?,O  
for(int i=1;;i++) =H8 LBM  
{ mEh([ZnY  
String header=con.getHeaderFieldKey(i); CGYZEPRR  
if(header!=null) hzR1O(  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2^3N[pM;  
Utility.log(header+" : "+con.getHeaderField(header)); xJ=@xfr$  
else 9| ('*  
break; mT:Z!sS  
} "~:AsZ"7  
} %t.L;G  
DAvF ND$=  
+c&oF,=}!P  
public void splitterStop() ?^f=7e8]  
{ gjbSB6[  
bStop = true; vZ0K1UTEXY  
} e"I+5r",  
m@A?'gD  
8l<4OgoK  
} 4nvi7  
%]U'   
8Pgw_ 21N1  
/* PjxZ3O  
**FileAccess.java SO!|wag$  
*//文件访问(定位,写) "bhF`,V  
package NetFox; B_ x?s  
import java.io.*; V DN@=/  
Gt|m;o  
8k.<xWDU  
public class FileAccessI implements Serializable{ I=;.o>  
8gI f  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 &xgKHbg  
RandomAccessFile oSavedFile; JA <Hm.V#  
long nPos; 8*$HS.Db'  
gL/D| =  
_Qh :*j!  
public FileAccessI() throws IOException *i`t4N A  
{ iCZuE:I1K,  
this("",0); PKxI09B  
} YU]|N 'mL2  
zxD~W"R:s  
KFuP gp  
public FileAccessI(String sName,long nPos) throws IOException Dwx^hNh  
{ dm:2:A8^  
oSavedFile = new RandomAccessFile(sName,"rw"); dX^d\ wX  
this.nPos = nPos; awC:{5R8v  
oSavedFile.seek(nPos); 3<"!h1x5  
} 1+Z@4;fk  
9| {t%F=-  
le*'GgU#  
public synchronized int write(byte[] b,int nStart,int nLen) vB<2f*U  
{ 8hZY Z /T  
int n = -1; 7A=*3  
try{ D\@)*"  
oSavedFile.write(b,nStart,nLen); zn3]vU!  
n = nLen; nD5+&M0  
} ag* 5fBF  
catch(IOException e) Y<WA-dYoF  
{ wRj||yay#-  
e.printStackTrace (); EvJ<X,Bo  
} 0e,U&B<W  
t(.jJ>|+*  
<aR sogu"P  
return n; x o{y9VS  
} V/dL-;W;  
7.W$6U5  
ahmxbv3f=5  
} t`!@E#VK  
&W*do  
q L-Ni  
/* tmgZNg  
**SiteInfoBean.java &`LR{7m  
*/ ;JHR~ TV  
package NetFox; O,_k.EH  
oa"_5kn,  
\&,{N_G#L.  
public class SiteInfoBean { 12 TX_0  
} b/Xui9Q  
OTmw/#ug  
private String sSiteURL; //Site's URL Co^^rd@  
private String sFilePath; //Saved File's Path %Mxc"% w  
private String sFileName; //Saved File's Name m2x=Qv][@c  
private int nSplitter; //Count of Splited Downloading File p`=v$_]?(  
9Z^\b)x  
k )=Gyv<  
public SiteInfoBean() d>1cKmH!  
{//nSplitter的缺省值为5 IA3m.Vxj ^  
//default value of nSplitter is 5 M/5+AsT  
this("","","",5); }J0HEpn4  
} tW[dJKw  
MD+e!A#o  
HbZFL*2x3  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) y8Oz4|  
{ ]q":ta!f  
sSiteURL= sURL; sD{d8s[(  
sFilePath = sPath; ,w|Or}h]7  
sFileName = sName; x4Wu`-4^  
this.nSplitter = nSpiltter; wN2D{Jj  
zS/1v+  
A2p]BW&  
} ?C`&*+  
E06)&tF  
UPGS/Xs]1  
public String getSSiteURL() ('oA{,#L  
{ 4DV@-  
return sSiteURL; GWCU 9n  
} ?d5_{*]+v  
pzFM#   
gaC [%M  
public void setSSiteURL(String value) .qfU^AHA  
{ Zk<Y+!  
sSiteURL = value; 8k9q@FSln  
} k* e $_  
]uZaj?%J<  
Dk#4^`qp1  
public String getSFilePath() +8Q5[lh2]j  
{ "Gc\"'^r  
return sFilePath; DPBWw[  
} a2.@Zyz  
m_C#fR /I  
z`2Ais@ao  
public void setSFilePath(String value) rGgP9 (  
{ HvJ-P#  
sFilePath = value; B{2WvPX~q  
} |576)  
,UATT]>  
iNG =x   
public String getSFileName() J}Ji /  
{ R d|M)  
return sFileName; G"|c_qX  
} v&3 Oc  
9FcH\2J  
9w}_CCj3  
public void setSFileName(String value) X(qs]:  
{ ]\6*2E{1m  
sFileName = value; N+CcWs!E  
} z"$huE>P6  
[n2)6B\/  
= 6.i.(L_S  
public int getNSplitter() WJBwo%J  
{ dCO7"/IHW  
return nSplitter; >7(7  
} ['DYP-1J  
x#jJ 0T  
yGE)EBH  
public void setNSplitter(int nCount) :S=!]la0h  
{ Xp?WoC N  
nSplitter = nCount; -o B` v'  
} a(IZ2Zmr  
} m.&"D> \t  
 E-L>.tD  
&]jCoBj+_  
/* w|( ix;pK  
**Utility.java miEf<<L#z  
*/ (&oT6Ji  
package NetFox; <hB~|a<#  
G`R_kg9$  
l *]nvd_  
public class Utility { 3}x6IM 2  
RWdx) qj{  
M <c cfU!  
public Utility() >gZ"^iW  
{ qLk7C0  
F ,h}HlU  
4mwLlYZ  
} }cd-BW  
ROj9#:  
//线程睡眠 #)z7&nD  
public static void sleep(int nSecond) tr$d?  
{ Bs';!,=  
try{ .Dt.7G  
Thread.sleep(nSecond); @X]J MicJ  
} z18<rj  
catch(Exception e) sV-UY!   
{ !WNO!S0/j  
e.printStackTrace (); |6T"T P  
} tW=oAy  
} t&nK5p95(  
b0h>q$b  
//日志 `V=F>s$W  
public static void log(String sMsg) R:Tv'I1-L  
{ R0bWI`$Z  
System.err.println(sMsg); ^9`~-w  
} }-%:!*bLj  
~5 e 1&  
q|S,^0cU  
public static void log(int sMsg) f1X]zk(=W  
{ U~_G *0  
System.err.println(sMsg); ?Suv.!wfLl  
} E#/vgm=W;  
} (&xIB F_6  
tN-B`d 1  
7-2,|(Xg  
/* &U{"dJr  
**TestMethod.java 'aJm4W&j  
*/ wY_! s Qo  
package NetFox; }080=E  
v.{I^=  
uV\~2#o$_  
public class TestMethod { "= >8UR  
EQ2HQz ]  
v0,&wdi  
public TestMethod() e|Mw9DIW  
{ ///xx/weblogic60b2_win.exe $X]Z-RCK3  
try{ R*>EbOuI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Yy4l -}"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0w ;#4X:m  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w02t9vz  
fileFetch.start(); _0!<iN L  
} [J+]1hCZ|  
catch(Exception e){e.printStackTrace ();} "Tc[1{eI  
M =6  
E9#.!re|^  
} MVZ9x%  
K?X 6@u|h  
U?(+ {4l  
public static void main(String[] args) Rv@( [rn+  
{ A =l1_8,`h  
new TestMethod(); SS"Z>talw  
} h f9yK6  
} N3o kN8d  
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