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http断点续传简单实现(java)

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/* a8r+G]Z  
**SiteFileFetch.java 1Yy*G-7}  
*/ 3G-f+HN^E  
package NetFox; Kw,ln<)2  
import java.io.*; }#9 |au`  
import java.net.*; `pYL/[5  
3Tr}t.mt  
U%_6'5s{^  
public class SiteFileFetch extends Thread { <N\#6m  
u3_AZ2-;  
\|Ya*8V  
SiteInfoBean siteInfoBean = null; //文件信息Bean =!PUKa3f<  
long[] nStartPos; //开始位置 5b%zpx0Y  
long[] nEndPos; //结束位置 0 +"P 1/  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \}NZ] l  
long nFileLength; //文件长度 R,[+9U|4V  
boolean bFirst = true; //是否第一次取文件 >)S'`e4Gu  
boolean bStop = false; //停止标志 wfc+E9E  
File tmpFile; //文件下载的临时信息 ru1FJ{n  
DataOutputStream output; //输出到文件的输出流 RaY=~g  
s h^&3}  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 5 }F6s  
public SiteFileFetch(SiteInfoBean bean) throws IOException >`+-Yi$(\  
{ 407;M%?'A  
siteInfoBean = bean; T|lyjX$Q]9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); zd#/zUPI  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); t^@4n&Dg  
if(tmpFile.exists ()) 0Kenyn4?  
{ &\s>PvnquX  
bFirst = false; "Kt[jV;6  
read_nPos(); ^tFgkzXm  
} YM]ZL,8  
else NpF}~$2  
{ }8&L?B;90  
nStartPos = new long[bean.getNSplitter()]; O8S"B6?$~'  
nEndPos = new long[bean.getNSplitter()]; ' C|yUsBC  
} a+{95"4  
K>fY9`Whm  
U0%m*i  
gSu3\keF  
} OgB ZoTT  
E[E[Za^Y  
|p{FSS  
public void run() \.jT"Z~  
{ B|n<{g[-cM  
//获得文件长度 /-jk_8@a  
//分割文件 h` $2/%?  
//实例FileSplitterFetch KmlpB  
//启动FileSplitterFetch线程 FR@## i$  
//等待子线程返回 xT1{O`  
try{ p&ml$N9fd  
if(bFirst) kVb8$Sp  
{ 6sp?'GO`~  
nFileLength = getFileSize(); _"#ucM=B:-  
if(nFileLength == -1) B#;yko  
{ UHW;e}O5  
System.err.println("File Length is not known!"); eA(c{  
} w/m ~#`a  
else if(nFileLength == -2) SgocHpyg  
{ obhq2sK  
System.err.println("File is not access!"); 5UHxB"`C  
} <sq@[\l}a  
else 7lz"^  
{ jNA^ (|:  
for(int i=0;i<nStartPos.length;i++) d>qxaX;  
{ #.n%$r  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); <xeo9'k6&  
} 3xnu SOdh  
for(int i=0;i<nEndPos.length-1;i++) |k^ *  
{ "|l-NUe  
nEndPos = nStartPos[i+1]; \aG:l.IM0  
} 4l*4w x""v  
nEndPos[nEndPos.length-1] = nFileLength; W8 m*co  
} L'Fy\K\  
} A_WtmG_9  
* F T )`  
bqDHLoB\1  
//启动子线程 "m:4e`_dz  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; o-jF?9m  
for(int i=0;i<nStartPos.length;i++) tgbr/eCoU  
{ ]h$,=Qf hD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ' Z}/3 dp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Dj9).lgc  
nStartPos,nEndPos,i); Zu/}TS9bi  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8?r RLM4  
fileSplitterFetch.start(); $lMEZt8A  
} r%/*,lLO  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H]7;O M/g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 3yfq*\_uXw  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )} H46  
nEndPos = " + nFileLength); yS[Z%]bvU  
// fileSplitterFetch[nPos.length-1].start(); 2nRL;[L*.  
E5<}7Pt  
VfiMR%i}  
//等待子线程结束 IJA WG  
//int count = 0; e/;chMCq  
//是否结束while循环 2$O @T]  
boolean breakWhile = false; ?][2J  
93npzpge  
?>W4*8 (  
while(!bStop) 0#rv.rJ{  
{ !be6}  
write_nPos(); -B-nTS`  
Utility.sleep(500); cR1dGNcp/@  
breakWhile = true; 2I#4jy/g  
f: h.O# d>  
[1Yx#t  
for(int i=0;i<nStartPos.length;i++) 9s-op:5  
{ w8Mi: ;6  
if(!fileSplitterFetch.bDownOver) mb\}F9  
{ zW_V)U Ne  
breakWhile = false; Sh=Px9'i  
break; x^| J-  
} YEWHr>&Z  
} w-%H\+J  
if(breakWhile) lr[a~ca\  
break; w$cic  
xPY/J#X$  
0omg%1vt<A  
//count++; E Cx_ [|3{  
//if(count>4) < ealt  
// siteStop(); F-)lRGw  
} < }3c%Q1  
L$GhM!c  
yVyh'd:Ik  
System.err.println("文件下载结束!"); M[ (mH(j  
} ,HEx9*E/s  
catch(Exception e){e.printStackTrace ();} e4V4%Qw  
} AT:T%a:G?  
d))(hk:  
$Wy7z^ t  
//获得文件长度 an 3"y6.8  
public long getFileSize() NW`.RGLI<  
{ xP.B,1\X  
int nFileLength = -1; ,x?H]a)  
try{ bc"E=z  
URL url = new URL(siteInfoBean.getSSiteURL()); }TZ5/zn.Dw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B8^tIq  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3:i4DBp,i  
UlHRA[SCv  
R<gC,eV<=  
int responseCode=httpConnection.getResponseCode(); 0}YR=  
if(responseCode>=400) Rla4XN=mf  
{ ~EIY(^|py  
processErrorCode(responseCode); v2dCkn /  
return -2; //-2 represent access is error ?gb"S,  
} _=1SR\  
hv'~S  
z^Nnt  
String sHeader; b'^OW  
${#5$U+kI  
I72UkmK`  
for(int i=1;;i++) }ZEh^zdz8  
{ zi23k=  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); N7%+n*Z  
//Utility.log(in.readLine()); 5r<%xanXW/  
sHeader=httpConnection.getHeaderFieldKey(i); "-y\F}TE  
if(sHeader!=null) Q/6T?{\U7  
{ dhN[\Z%  
if(sHeader.equals("Content-Length")) Ru Q\H0pr  
{ p;:tzH\l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); <0T4MR7  
break; (}fbs/8\p  
} aC>r5b#:  
} TRrO-  
else .9Bimhc6K  
break; e0HG"z4  
} PKR0y%Ar  
} "_ b Sy  
catch(IOException e){e.printStackTrace ();} PNXZ3:W  
catch(Exception e){e.printStackTrace ();} J.:"yK""  
.Lo$uKsW$l  
/d5_-AB(v  
Utility.log(nFileLength); a\\B88iRRZ  
4@|K^nT`  
h)q:nlKUW  
return nFileLength; PG9won5_  
} $Trkow%F]  
=1lKcA[z  
J={$q1@lq  
//保存下载信息(文件指针位置) -9/YS  
private void write_nPos() 9U6y<X  
{ 6rL'hB!!]*  
try{ j4le../N  
output = new DataOutputStream(new FileOutputStream(tmpFile)); GEwgwenv  
output.writeInt(nStartPos.length); TH/!z,( >  
for(int i=0;i<nStartPos.length;i++) &-+qB >SK>  
{ 4hztYOhJ{  
// output.writeLong(nPos); epm  t  
output.writeLong(fileSplitterFetch.nStartPos); R! ?8F4G  
output.writeLong(fileSplitterFetch.nEndPos); +&tY&dQQB  
} *9%<}z  
output.close(); f3U#|(%(*  
} A\ze3fmV  
catch(IOException e){e.printStackTrace ();} BD,JBu]  
catch(Exception e){e.printStackTrace ();} UuAn`oYhV  
} mwCNfwb:  
-B$oq8)n*  
{$>*~.Wu  
//读取保存的下载信息(文件指针位置) OekcU% C  
private void read_nPos() -:m;ePK  
{ 4QK([q  
try{ whoz^n3NE  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); F&;g< SD  
int nCount = input.readInt(); dW<.  
nStartPos = new long[nCount]; pq*b"Jku1  
nEndPos = new long[nCount]; fu9y3`  
for(int i=0;i<nStartPos.length;i++) BgD;"GD*W  
{ h|dVVCsN  
nStartPos = input.readLong(); Mq42^m:qe  
nEndPos = input.readLong(); d6<,R;)  
} u.0Z)j}N  
input.close(); nTY`1w.;  
} @.T'  
catch(IOException e){e.printStackTrace ();} |A 7Yv  
catch(Exception e){e.printStackTrace ();} :D-d`OyjG>  
} Ka2U@fK"  
`?rPs8+R  
@fT*fv   
private void processErrorCode(int nErrorCode) p{!aRB%  
{ Vlce^\s;  
System.err.println("Error Code : " + nErrorCode); -hL8z$}  
} 5|x FY/%  
{LJwW*?  
9+9}^B5@A  
//停止文件下载 29 u"\f a  
public void siteStop() $WnK  
{ #@Zz Bf  
bStop = true; ag14omM-  
for(int i=0;i<nStartPos.length;i++) G?e,Q$  
fileSplitterFetch.splitterStop(); v@`#!iu  
6,uW{l8L  
LcE!e%3  
} }@4m@_gR?  
} B c*Rn3i@  
//负责部分文件的抓取 j)C%zzBu(  
**FileSplitterFetch.java XV)ej>A-V  
*/ t3 *2Z u  
package NetFox; Hy|$7]1  
%S$`cp  
X~5TA)h;~  
import java.io.*; iYHD:cg)~  
import java.net.*; =bZ>>-<  
k x6%5%  
R7e`Wn  
public class FileSplitterFetch extends Thread { l:8gCi  
]XJpy-U  
jr*A1y*  
String sURL; //File URL g$?B!!qT  
long nStartPos; //File Snippet Start Position  o9#  
long nEndPos; //File Snippet End Position ~!,'z  
int nThreadID; //Thread's ID <'-}6f3  
boolean bDownOver = false; //Downing is over G#)>D$Ck#  
boolean bStop = false; //Stop identical 4Me*QYD  
FileAccessI fileAccessI = null; //File Access interface 5IBe;o  
E0>4Q\n{  
@;fdf3ian  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException T WEmW&Q  
{ 5ts8o&|   
this.sURL = sURL; XkCbdb  
this.nStartPos = nStart; d'kQE_y2.  
this.nEndPos = nEnd; tu6c!o,@  
nThreadID = id; z++*,2F  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ^g~Asz5]  
} C:_!zY'z  
%xyt4}-)m  
K4N~ApLB+  
public void run() 45edyQ  
{ |`U^+Nf  
while(nStartPos < nEndPos && !bStop) !?Z}b.%W  
{ ,78 QLh9:  
my[)/'  
niFX8%<hP  
try{ I^[R]Js  
URL url = new URL(sURL); /o.wCy,J<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 2 Nr j@q  
httpConnection.setRequestProperty("User-Agent","NetFox"); Z%N{Y x(  
String sProperty = "bytes="+nStartPos+"-"; G!8O*4+A  
httpConnection.setRequestProperty("RANGE",sProperty); pYI`5B4  
Utility.log(sProperty); MH?|>6  
PD$ay^Y  
:'f#0ox  
InputStream input = httpConnection.getInputStream(); aa.EtKl  
//logResponseHead(httpConnection); S$%T0~PR~  
hp%|n:.G  
4M6o+WV  
byte[] b = new byte[1024]; =KmjCz:  
int nRead; XtNe) Ry  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) bb$1RLyRL  
{ oS/<)>\Gv  
nStartPos += fileAccessI.write(b,0,nRead); VZ}^1e  
//if(nThreadID == 1) ul?'kuYk  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8QE0J$d5  
} l-XiQ#-{  
{uL<$;#i  
:7e2O!zH_  
Utility.log("Thread " + nThreadID + " is over!"); ya5;C"   
bDownOver = true; pTST\0?  
//nPos = fileAccessI.write (b,0,nRead); Um4 }`  
} tUGnD<P  
catch(Exception e){e.printStackTrace ();} s59v* /  
} *["9;_KD  
} YnNB#x8|  
UVUbxFq:  
!Jh-v  
//打印回应的头信息 G>M# BuU  
public void logResponseHead(HttpURLConnection con) f:B+R  
{ .*r ?zDV  
for(int i=1;;i++) ` *&*jdq&i  
{ PnFU{N  
String header=con.getHeaderFieldKey(i); xA`Q4"[I  
if(header!=null) S?D|"#-,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pez[qs  
Utility.log(header+" : "+con.getHeaderField(header)); 6U @3 xU`  
else %?<C ?.  
break; kmi[u8iXD_  
} (VO) Q  
} w_ kHy_)  
IwZn%>1N  
e/6WhFN #  
public void splitterStop() n (C*LK  
{ GL cf'$l  
bStop = true; d?oupW}uu  
} 1 C{n!l  
y/$WjFj3"  
!qV{OXdrB  
} " nq4!  
m[LIM}Gu  
!<h*\%;  
/* *%:p01&+  
**FileAccess.java ZC_b`q<  
*//文件访问(定位,写) c;xL.  
package NetFox; d}EGI  
import java.io.*; 2Y(P hw2%  
~x)Awdlu  
K,&)\r kzD  
public class FileAccessI implements Serializable{ N0O8to}V  
$LRvPan`  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -w1U /o.  
RandomAccessFile oSavedFile; _UT>,c;h  
long nPos; Dq)V] Zx  
@g }r*U?  
*Y?rls`  
public FileAccessI() throws IOException <T)9mJYr  
{ I+kGEHO}  
this("",0); V()s! w  
} L~"~C(g  
'\(Us^Ug  
MBIt)d@Ix  
public FileAccessI(String sName,long nPos) throws IOException N|O/3:P<,U  
{ N$aLCX  
oSavedFile = new RandomAccessFile(sName,"rw"); T6=c9f?7  
this.nPos = nPos; f>s3Q\+  
oSavedFile.seek(nPos); Lco JltY{5  
} Om0Z\GP=  
@.yp IE\  
[c +[t3dz  
public synchronized int write(byte[] b,int nStart,int nLen)  "9!ln  
{ WogJ~N,d53  
int n = -1; VE+Q Y9(  
try{ :XxsDD  
oSavedFile.write(b,nStart,nLen); BKPXXR  
n = nLen; b/:9^&z  
} ?[hIv6c  
catch(IOException e) +;c)GNQ)6:  
{ a}|B[b  
e.printStackTrace (); R+Dx#Wn I  
} dGt;t5An V  
f>k]{W Y  
8)s}>:}  
return n; Rb Jl;  
} oS 7q#`  
0j %s H  
dZFf /BXU  
} qZ'&zB)  
c~3OK_k  
V2Q2(yvdJ  
/* sWX iY  
**SiteInfoBean.java OCnQSkj  
*/ a x4V(  
package NetFox; \L>3E#R-Q  
RZ#b)l  
5 < wIJ5t  
public class SiteInfoBean { sMlY!3{I x  
NYA,  
~2@+#1[g8z  
private String sSiteURL; //Site's URL LX[<Wh_X(  
private String sFilePath; //Saved File's Path @;_xFL;{g  
private String sFileName; //Saved File's Name .K]n<+zW  
private int nSplitter; //Count of Splited Downloading File "_WOt Jr  
=+% QfuK  
S@* lI2  
public SiteInfoBean() :V*c9,>ZO  
{//nSplitter的缺省值为5 wa-#C,R\_#  
//default value of nSplitter is 5 "#\\p~D/<  
this("","","",5); :*u .=^  
} 9gVu:o 1/  
v^1_'P AXu  
k%YvJXL  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) L'B= =#  
{ `qnSq(tNq  
sSiteURL= sURL; Clr~:2g\  
sFilePath = sPath; ?9'Ukw` g  
sFileName = sName; = &jLwy  
this.nSplitter = nSpiltter; =Y Je\745  
h}r.(MVt  
U2 m86@E  
} LfOXgn\  
[vh&o-6  
{Z%4Pg  
public String getSSiteURL() }iZO0C  
{ 2L Kpwz?  
return sSiteURL; <Dojl #  
} 5V5Nx(31i  
.`*h2  
Mhp6,JL  
public void setSSiteURL(String value) 3]"RaI4Q0  
{ V<:scLm#OF  
sSiteURL = value; wXI6KN-  
} '0|0rwx  
"I+71Ce  
u}Kc>/AF  
public String getSFilePath() S bI7<_  
{ E>>@X^ =  
return sFilePath; LgFF+z  
} qM%l  
$fZVh%  
w6FtDl$  
public void setSFilePath(String value) P(AcDG6K  
{ |rW,:&;  
sFilePath = value; n1n->l*HGP  
} s\&qvL1D  
}\Kki  
ukNB#2 "  
public String getSFileName() .rpKSf.  
{ is`O,Met  
return sFileName; :+Ti^FF`w  
} r0jhIE#  
rUgTJx&ds  
T7+_/ Qh  
public void setSFileName(String value) t$+[(}@ +  
{ K6 D3  
sFileName = value; 86+nFk  
} bz$)@gLc  
N;N,5rxV  
4FLL*LCNX  
public int getNSplitter() (NB\wJg $  
{ G_OLUuK?C  
return nSplitter; mtfEK3?2*  
} NABVU0}   
^q{=mf`  
KlOL5"3  
public void setNSplitter(int nCount) V% -wZL/  
{ =VXxQ\{  
nSplitter = nCount; QxUsdF?p  
} SA3!a.*c  
} W<']Q_su  
6IRzm6d  
leY fF  
/* ";vP77|m7R  
**Utility.java )S~ySiJ<U  
*/ oW7\T !f  
package NetFox; &4]~s:F  
lJ y\Ky(*  
A\xvzs.d  
public class Utility { M{)7C,'  
AE?G+:B  
2$S^3$k'  
public Utility() bSbUf%LKt  
{ 7l+>WB_]  
@x u/&pbI  
Cx,)$!1  
} 22`N(_  
@-d0 ~.S  
//线程睡眠 ~:Pu Kx  
public static void sleep(int nSecond) A08b=S  
{ iRwlK5(&  
try{ vBRW5@  
Thread.sleep(nSecond); >n!,KUu]  
} 7"|j.Yq$H{  
catch(Exception e) !`UHr]HJ  
{ uW@o,S0:  
e.printStackTrace (); 6<%W 8m\  
} e 9p+  
} t93iU?Z  
wfE%` 1  
//日志 ;8VvpO^G/  
public static void log(String sMsg) PR{y84$  
{ 3jaY\(`%h  
System.err.println(sMsg); WZ#|?pJ  
} jjbw+  
d|~A>YZ  
k~P{Rm;F  
public static void log(int sMsg) OI0tgkG  
{ W5#5RK"uX  
System.err.println(sMsg); ga#Yd}G^~3  
} O7KR~d  
} gp?|UMA9 .  
JE[+  
1Vden.H*CI  
/* *CnrzrKtQ  
**TestMethod.java ohy?l  
*/ Wd0$t    
package NetFox; #!h +K"wX  
Y64B"J=P 9  
x?|C-v  
public class TestMethod { c[a1 Md&  
*, Mg  
Xy;!Q`h(  
public TestMethod() Z T5p  
{ ///xx/weblogic60b2_win.exe 6Eu&%`  
try{ G0u3*.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Gkfc@[Z V  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); .W9/*cZV0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); cdH Ug#  
fileFetch.start(); ~w>Z !RuhT  
} Ob|[/NN  
catch(Exception e){e.printStackTrace ();} l:Y$A$W]>  
[;]@PKW?w  
JN{xh0*  
} _tGR:E  
%5zztReI  
9gz"r  
public static void main(String[] args) aD5G0d?u  
{ VB?mr13}G  
new TestMethod(); +]!`>  
} o`@B*, @  
} JW5SBt>  
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