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http断点续传简单实现(java)

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/* U.%Kt,qB  
**SiteFileFetch.java {zdMmpQF  
*/ c'2d+*[  
package NetFox; rqdwQ  
import java.io.*; \@LTXH.  
import java.net.*; ^J!q>KJs  
bx@l6bpQ  
V~J5x >O  
public class SiteFileFetch extends Thread { qQ&uU7,#  
Cs'LrUB?=U  
 N;7/C  
SiteInfoBean siteInfoBean = null; //文件信息Bean `8:0x?X  
long[] nStartPos; //开始位置 qUe _B  
long[] nEndPos; //结束位置 pSZ2>^";  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @f!X%)\;x  
long nFileLength; //文件长度 1>!LK_  
boolean bFirst = true; //是否第一次取文件 Cy/&KWLenf  
boolean bStop = false; //停止标志 U|(+-R8Z  
File tmpFile; //文件下载的临时信息 -N *L1Zj  
DataOutputStream output; //输出到文件的输出流 EY}:aur  
}aCa2%  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) #YUaM<O  
public SiteFileFetch(SiteInfoBean bean) throws IOException 1<@SMcj>  
{ _T=g?0 q  
siteInfoBean = bean; ~Bd=]a$mj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); $o^Z$VmL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); JzHG5nmB  
if(tmpFile.exists ()) =bVPHrKNQ  
{  >@ t  
bFirst = false; C@rGa7  
read_nPos(); t^t% >9o  
} XR5KJl  
else ZykMri3bi  
{ 5of3&  
nStartPos = new long[bean.getNSplitter()]; zM0NRERi  
nEndPos = new long[bean.getNSplitter()]; =W(*0"RM  
} B5e9'X^ [  
p6VD*PT$&  
4ls:BO;k]  
*6uccx7{  
} Dn- gP  
"tK%]c d-  
:FyF:=  
public void run() &y[NC AeA  
{ K%(y<%Xp  
//获得文件长度 5~Y`ikwxL  
//分割文件 5{Cz!ut;tE  
//实例FileSplitterFetch uOxHa>h  
//启动FileSplitterFetch线程 hbjAxioA  
//等待子线程返回 a"8[,A3  
try{ sdu?#O+c1  
if(bFirst) }`"`VLh  
{ W&z jb>0b0  
nFileLength = getFileSize(); kc,"w\ ai  
if(nFileLength == -1) ?b7\m":'  
{ 7>JYwU{  
System.err.println("File Length is not known!"); `i7r]  
} IThd\#=  
else if(nFileLength == -2) . ,7bGY 1$  
{ p!.~hw9  
System.err.println("File is not access!"); n|`3d~9$&  
} n ]ikc|  
else Jh[0xb  
{ Onmmcem  
for(int i=0;i<nStartPos.length;i++) HpwMm^  
{ V\V /2u5-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |<%!9Z  
} KKeMi@N  
for(int i=0;i<nEndPos.length-1;i++) %!|w(Povq  
{ >1y6DC  
nEndPos = nStartPos[i+1]; ?ukw6T  
} 1Pf(.&/9_  
nEndPos[nEndPos.length-1] = nFileLength; S_}`'Z )  
} Cj5mM[:s  
} Lu.zc='\  
 *kr/,_K  
>rG>Bz^Pu  
//启动子线程 LQ0/oYmNc  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; yNu_>!Cp5  
for(int i=0;i<nStartPos.length;i++) ?^|`A}q#  
{ 18g_v"6o  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Hl*vS  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Cu"Cpt[  
nStartPos,nEndPos,i); .nV2 n@SR  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >J"IN I  
fileSplitterFetch.start(); DA=!AK>  
} ,'#TdLe  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7y=>Wa?T[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3"fDFR  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", A_9WSXR  
nEndPos = " + nFileLength); qT O6I5u  
// fileSplitterFetch[nPos.length-1].start(); Z\0Rw>#  
xm'9n?  
@sXFu[!U  
//等待子线程结束 _vQ52H,  
//int count = 0; XTol|a=  
//是否结束while循环 UK`A:N2[  
boolean breakWhile = false; L"_X W no  
#h5:b`fDF  
A|A~$v("R  
while(!bStop) H DVimoOq  
{ bMH~vR  
write_nPos(); {@Wv@H+4  
Utility.sleep(500); rTD+7 )E  
breakWhile = true; ?vXgHDs^T  
wjarQog5Y  
=u~nLL  
for(int i=0;i<nStartPos.length;i++) Lx"GBEkt7  
{ |Q?h"5i"(  
if(!fileSplitterFetch.bDownOver) _\!]MV  
{ ;m/e|_4;y  
breakWhile = false; nF3}wCe)  
break; r924!zdbR  
} %L|fTndKH  
} H R>Y?B{  
if(breakWhile) l.YE@EL  
break; fHt\KP  
=C %)(|  
bQ< qdGa  
//count++; <'y<8gpM  
//if(count>4) ;p`1Y<d-O  
// siteStop(); AGhenDN V  
} *X5)9dq  
 Spm 0`  
6F\ 6,E  
System.err.println("文件下载结束!"); %"RJi?  
} ]lWqV  
catch(Exception e){e.printStackTrace ();} X+vKY  
} I8H3*DE  
LG}{ibB  
kR]P/4r  
//获得文件长度 q8 v iC|  
public long getFileSize() rxCzPF  
{ iOL$|Z(  
int nFileLength = -1; l{By]S  
try{ RQ+,7Ir  
URL url = new URL(siteInfoBean.getSSiteURL()); !V|{(>+<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (m]l -Re  
httpConnection.setRequestProperty("User-Agent","NetFox"); ["Zvwes#7  
G|i0n   
~id6^#&>  
int responseCode=httpConnection.getResponseCode(); zAgX{$/Fg  
if(responseCode>=400) Z0gtliJ@  
{ Y;'<u\^M"  
processErrorCode(responseCode); D 0Xl`0"'  
return -2; //-2 represent access is error ( eV,f  
} *&U~Io"U  
[6GYYu\  
>hunV'vu'  
String sHeader; %9-^,og  
D(b01EQ;d  
fk*(8@u>  
for(int i=1;;i++) -L2.cN_  
{ !Ko2yn}6l  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 3(YvqPp&  
//Utility.log(in.readLine()); Hv6h7-  
sHeader=httpConnection.getHeaderFieldKey(i); ) f?I{  
if(sHeader!=null) !gh8 Qs  
{ i_qY=*a?y  
if(sHeader.equals("Content-Length")) \w9}O2lL  
{ E@VQxB7+  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (s8b?Ol/  
break; zJQh~)  
} OB>Hiy   
} S-t#d7'B  
else AD?zBg Zu  
break; 41 F;X{Br  
} N8A)lYT]_u  
} .?}M(mL  
catch(IOException e){e.printStackTrace ();} c *KE3:  
catch(Exception e){e.printStackTrace ();} }#z1>y!#  
?v^NimcZ  
M/S~"iD  
Utility.log(nFileLength); 4o>y9  
\gA!)q.;  
~^wSwd[  
return nFileLength; NuZ2,<~9  
} Dfs^W{YA  
=VC18yA  
=Rd`"]Mnfb  
//保存下载信息(文件指针位置) U`v2Yw3E  
private void write_nPos() "@ >6<(Ki  
{ +pd,gG?dW  
try{ X[tt'5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); W(q3m;n  
output.writeInt(nStartPos.length); '-wmY?ZFxy  
for(int i=0;i<nStartPos.length;i++) reu[rZ&  
{ %;`Kd}CO  
// output.writeLong(nPos); j~v`q5X  
output.writeLong(fileSplitterFetch.nStartPos); <J509j  
output.writeLong(fileSplitterFetch.nEndPos); j>8DaEfwx  
} ;|Cd q  
output.close(); b.*LmSX#  
} c^}G=Z1@  
catch(IOException e){e.printStackTrace ();} yan^\)HZ  
catch(Exception e){e.printStackTrace ();} \Qml~?$@lH  
} tYA@J["^  
?Y"%BS+pt  
161P%sGx2  
//读取保存的下载信息(文件指针位置) 0O3O^ 0  
private void read_nPos() $;v! ,>  
{ ?(ORk|)kU  
try{ -K|1w'E  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ly[yn{  
int nCount = input.readInt(); r]9-~1T  
nStartPos = new long[nCount]; WNR]GI  
nEndPos = new long[nCount]; vF\>;pcT  
for(int i=0;i<nStartPos.length;i++) O_QDjxj^rZ  
{ z'l$;9(y  
nStartPos = input.readLong(); t:wBh'K~R8  
nEndPos = input.readLong(); $dM_uSt  
} i{$-[*WHiV  
input.close(); Vh-8pF t  
} K0w}l" )A  
catch(IOException e){e.printStackTrace ();} =O}I{dNKZV  
catch(Exception e){e.printStackTrace ();} S:1[CNL;  
} CPB{eQeDuv  
Es>' N3A z  
1$Hou   
private void processErrorCode(int nErrorCode) Q4XlYgIV2A  
{ oh5'Isb$  
System.err.println("Error Code : " + nErrorCode); 4DL;Y  
} }c G)$E  
yaz6?,)  
|>Q>d8|k  
//停止文件下载 ~n=DI/AJ@-  
public void siteStop() 2u.0AG   
{ ^ITF*  
bStop = true; $J1`.Q>)4  
for(int i=0;i<nStartPos.length;i++) rHKO13WF  
fileSplitterFetch.splitterStop(); d(IJ-qJ N  
bi8_5I[  
qU26i"GHp  
} !Z_+H<fi+I  
} e!6yxL*[@[  
//负责部分文件的抓取 ebA95v`Vms  
**FileSplitterFetch.java =$OGHc  
*/ suEK;Bk9  
package NetFox; bM?gAY]mB8  
7O1MC 8{  
8N&' n  
import java.io.*; oAO{4xP  
import java.net.*; XG|N$~N+2  
(d4btcg  
V]|X ,G  
public class FileSplitterFetch extends Thread { [8T{=+k  
tz ;3  
cWW?@ _  
String sURL; //File URL UZ<K'H,q  
long nStartPos; //File Snippet Start Position ;JxL>K(  
long nEndPos; //File Snippet End Position q,Gymh;  
int nThreadID; //Thread's ID puPI ^6y%  
boolean bDownOver = false; //Downing is over b8K]>yDAh  
boolean bStop = false; //Stop identical ^J]&($-  
FileAccessI fileAccessI = null; //File Access interface *RkUF!)(  
k`5I"-e  
WW:G( \`  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ^ ]9K>}  
{ ///Lg{ ie  
this.sURL = sURL; 96w2qgc2  
this.nStartPos = nStart; bK:U:vpYm  
this.nEndPos = nEnd; ((ebSu2-?$  
nThreadID = id; <vcU5 .K.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 FKO2UY#&7  
} `D;*.zrA  
pGD@R=8  
xMr,\r'+  
public void run()  VAiJL  
{ M5{#!d}^D  
while(nStartPos < nEndPos && !bStop) "pkdZ   
{ a``|sn9  
]g-%7g|  
{+9RJmZg  
try{ i"&FW&W  
URL url = new URL(sURL); MtkU]XKGT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &nIu^,.  
httpConnection.setRequestProperty("User-Agent","NetFox"); F85_Lz4  
String sProperty = "bytes="+nStartPos+"-"; uZ6krI  
httpConnection.setRequestProperty("RANGE",sProperty); C8K2F5c5  
Utility.log(sProperty); _mSefPl  
1(DiV#epG  
 GK/Po51  
InputStream input = httpConnection.getInputStream(); ZV gfrvZP  
//logResponseHead(httpConnection); T-N>w;P  
JP8}+  
Et3I(X3  
byte[] b = new byte[1024]; d?7?tL2  
int nRead; `XxnQng  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) @v2<T1UC  
{ { b$"SIg1E  
nStartPos += fileAccessI.write(b,0,nRead); 3en 9TB  
//if(nThreadID == 1) mG S4W;  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z>W:+W"o  
} %>FtA)  
>._d2.Q'  
Uxjc&o  
Utility.log("Thread " + nThreadID + " is over!"); -leX|U}k  
bDownOver = true; Q]9$dr=Kk0  
//nPos = fileAccessI.write (b,0,nRead); r *K  
} ! JA;0[;l=  
catch(Exception e){e.printStackTrace ();} Cu7{>"  
} 529b. |  
} Na91K4r#  
.I:rb~ &  
>[ B.y  
//打印回应的头信息 s#Dj>Fej  
public void logResponseHead(HttpURLConnection con) {<yapBMw  
{ ZR!8hw8  
for(int i=1;;i++) `=Ip>7T&  
{ )'kpO>_G  
String header=con.getHeaderFieldKey(i); _V$'nz#>e  
if(header!=null) 6nTM~]5.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -,")GA+[7  
Utility.log(header+" : "+con.getHeaderField(header)); j*>J1M3E  
else [1rQ'FBB^1  
break; =muQ7l:(  
} {JfQQP&FV  
} IHTim T?  
p{Q6g>?[  
c~hH 7/v  
public void splitterStop() M|blg!j;  
{ |O(>{GH  
bStop = true; t9`{^<LH  
} /1 EAj  
qA[lL(  
gBqDx|G  
} ?L }>9$"  
 rDFrreQP  
"VZ1LVI  
/* y`RzcXblIZ  
**FileAccess.java dgP e H8_  
*//文件访问(定位,写) ;g0s1nz  
package NetFox; rMwa6ZO'm;  
import java.io.*; jf3Zy :*K  
t2,II\K l  
.{ v$;g  
public class FileAccessI implements Serializable{ SXw r$)4_  
k3bQ32()  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 r<0E[ ~  
RandomAccessFile oSavedFile; *duG/?>P  
long nPos; dBI-y6R  
Y|R=^ =d\  
_9>,9aL  
public FileAccessI() throws IOException Hf('BagBL  
{ SRfh{u  
this("",0); m]?Z_*1  
} 9\"\7S/Z  
btg= # u  
b d 1^  
public FileAccessI(String sName,long nPos) throws IOException }{F)Ren  
{ Pk;w.)kT  
oSavedFile = new RandomAccessFile(sName,"rw"); CFFb>d  
this.nPos = nPos; `ArUoYb B  
oSavedFile.seek(nPos); %* 0GEfl/  
} v\@qMaPY  
5[;[Te9=S  
e_b,{l#  
public synchronized int write(byte[] b,int nStart,int nLen) Ii+3yE@c  
{ Bj 7* 2}  
int n = -1; XH%pV  
try{ /[TOy2/;%b  
oSavedFile.write(b,nStart,nLen); UIEvwQ  
n = nLen; c~U0&V_`j  
} GQt5GOt  
catch(IOException e) 0$|VkMq(  
{ "-f]d~P>  
e.printStackTrace (); k^}[+IFJ  
} -f|/#1  
SNqSp.>-U"  
1NP  
return n; _\>y[e["p  
} 2mEqfy  
C@Wzg  
I7vP*YE 7F  
} 5.^pD9[mT  
0#NMNZ  
bkJ bnW=  
/* .6gx|V+  
**SiteInfoBean.java  ,t 2CQ  
*/ uUfw"*D  
package NetFox; Ij(dgY  
XEiVs\) G  
uL)MbM]  
public class SiteInfoBean { im*sSz 0 (  
7=fM}sk  
"\*)KH`C  
private String sSiteURL; //Site's URL a>GA=r  
private String sFilePath; //Saved File's Path 3.YH7rN  
private String sFileName; //Saved File's Name | +;ZC y  
private int nSplitter; //Count of Splited Downloading File DG;u_6;JR  
{APfSD_4  
O ?T~>|  
public SiteInfoBean() Gxd/t#;  
{//nSplitter的缺省值为5 `&NFl'l1C  
//default value of nSplitter is 5 v.W!  
this("","","",5); "5eD >!  
} p>)1Z<D"a  
=+X*$'<J  
;,-)Z|W  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |Kd6.Mx  
{ @ fMlbJq  
sSiteURL= sURL; vE9"1M  
sFilePath = sPath; dFg&|Lp  
sFileName = sName; {b-C,J  
this.nSplitter = nSpiltter; 6Y[&1c8  
9-n]_AF`0  
DSs/D1mj&  
} <vl(a*4a  
#xmiUN,|  
^(&2  
public String getSSiteURL() ^RnQX#+  
{ Y<;C>Rs  
return sSiteURL; ]/ !*^;cY(  
} Q+f |.0r  
!}c D e12  
@16y%]Q-E#  
public void setSSiteURL(String value) Jha*BaD~N  
{ U+VJiz<!  
sSiteURL = value; <@`K^g;W  
} ~6#mVP5sU)  
ZS:[ZehF  
S*}GW-)oA  
public String getSFilePath() =3,<(F5Y[  
{ nxN("$'cq  
return sFilePath; pjO  
} 5 n4/}s  
07^.Z[(pCt  
mV]~}7*Y;  
public void setSFilePath(String value) l&Q@+xb>  
{ gs2qLb  
sFilePath = value; NZ`6iK-V_  
} {;bec%pq0  
8;=?F>]xn  
W=2.0QmW  
public String getSFileName() bY`Chb.  
{ |\B\IPs{%'  
return sFileName; L\Oxyi<{  
} ' Sd&I:?  
h%:wIkZ/  
a:|]F|  
public void setSFileName(String value) :8n?G  
{ .aZB?M W  
sFileName = value; :x q^T  
} Iy5W/QK6  
~i^,Z&X:  
pnz@;+f  
public int getNSplitter() D vEII'-h  
{ Wm8BhO  
return nSplitter; 3s BWtz  
} q&ed4{H<  
EHe-wC  
fR.raI4et  
public void setNSplitter(int nCount) nb5%a   
{ a[^dK-  
nSplitter = nCount; F`Vp   
} Zo-Au  
} zh !/24p9  
JmF`5  
K~L"A]+  
/* @TKQ_7BcB  
**Utility.java 7({.kD6  
*/ $o\U q  
package NetFox; p*P0<01Z  
P\c0Q;){h"  
(I`< ;  
public class Utility { hy"p8j7_  
etW-gbr  
/C<} :R  
public Utility() a(o[ bH.|;  
{ iEFS>kL8e  
cNN_KA  
jM@@N.  
} AM gvk`<f  
;c~DBJg'|  
//线程睡眠 F7x< V=4{  
public static void sleep(int nSecond) p|Fhh\,*`X  
{ G`!;RX  
try{ A&'HlI% J  
Thread.sleep(nSecond); F0NNS!WP7^  
} (aCl*vV1  
catch(Exception e) J! eVw\6  
{ nfvs"B;  
e.printStackTrace (); Z.LF5ur  
} S67T:ARS  
} FHH2  
zGFW?|o<  
//日志 [TV"mA  
public static void log(String sMsg) }\ui} \  
{ 5Q72.4HH  
System.err.println(sMsg); =TI|uD6T  
} .uagD[${  
d>4e9M "  
13{"sY:PT#  
public static void log(int sMsg) {&(bKQ  
{ ]O&A:Us  
System.err.println(sMsg); +ACV,GG  
} ;v+CQx  
} OEGAwP?F  
>Q\H1|?  
ELNA-ZKp  
/*  WU,72g=  
**TestMethod.java Zr 2QeLQC(  
*/ FkE CY  
package NetFox; B 9]sSx  
{78*S R  
{K0T%.G  
public class TestMethod { uJp}9B60_  
g9"_BG  
<F.Ol/'h  
public TestMethod() 7#|NQ=yd  
{ ///xx/weblogic60b2_win.exe Sdt2D  
try{ &FvNz  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); lB\j>.c  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?y45#Tk]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); LveqG   
fileFetch.start(); +Vf|YLbhJ  
} S(-=I!.G{  
catch(Exception e){e.printStackTrace ();} E 0pF; P5  
CX'E+  
s9GPDfZ  
} TAC\2*bWje  
@%cJjZ5y  
"RX?"pB  
public static void main(String[] args) {}^ELw  
{ LA@}{hU  
new TestMethod();  FZ2-e  
} hJ4.:  
} <,hBoHZSL  
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