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http断点续传简单实现(java)

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/* Hsl{rN  
**SiteFileFetch.java F= i!d,S  
*/ F^rl$#pCS  
package NetFox; b1=pO]3u  
import java.io.*; q\H7& w  
import java.net.*; F+*Q <a4  
) `I=oB  
4$Pr|gx  
public class SiteFileFetch extends Thread { Qa?aL  
.Cr1,Po  
`a'` $'j  
SiteInfoBean siteInfoBean = null; //文件信息Bean C1 {ZW~"YI  
long[] nStartPos; //开始位置 if@,vc  
long[] nEndPos; //结束位置 S'@=3)  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 *w 21U!  
long nFileLength; //文件长度 sR! +d:LJ4  
boolean bFirst = true; //是否第一次取文件 T*\$<-^  
boolean bStop = false; //停止标志 w_H2gaQ  
File tmpFile; //文件下载的临时信息 >0V0i%inmF  
DataOutputStream output; //输出到文件的输出流 #eLN1q&Z  
/e<5Np\X  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) :gaETr  
public SiteFileFetch(SiteInfoBean bean) throws IOException kW(Kh0x  
{ {F!v+W>  
siteInfoBean = bean; ,Hh*3rR^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); v= 8VvT 8  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); wA",SBGX  
if(tmpFile.exists ()) Y^3)!>  
{ 1p=&WM  
bFirst = false; 4k$0CbHx0  
read_nPos(); H;wR  
} M8_R  
else +"Ub/[J{G1  
{ Gl;f#}  
nStartPos = new long[bean.getNSplitter()]; J {!'f| J  
nEndPos = new long[bean.getNSplitter()]; X~zRZ0  
} P57GqT  
?\M)WDO  
P'F~\**5  
k- vA#  
} e?1KbJ?.  
GoL|iNW`  
UAKu_RO6S  
public void run() -xTKdm D  
{ vG3M5G  
//获得文件长度 gi 5XP]z  
//分割文件 $^IjFdD  
//实例FileSplitterFetch ()B7(Y  
//启动FileSplitterFetch线程 _eh3qs:  
//等待子线程返回 d.I%k1`(  
try{ nUqL\(UuY  
if(bFirst) I3An57YV].  
{ AbG&9=Ks  
nFileLength = getFileSize(); ]f5c\\)  
if(nFileLength == -1) S%{lJYwXt  
{ fOLnK y#  
System.err.println("File Length is not known!"); > '.[G:b  
} K?JV]^  
else if(nFileLength == -2) k|5k8CRX  
{ UtPwWB_YV  
System.err.println("File is not access!"); I<KCt2:X  
} :-U53}Iy  
else :^5>wDu{  
{ -zR.'x%  
for(int i=0;i<nStartPos.length;i++) &rcdr+'  
{ )Z&HuEg{ZR  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); "H@Fe  
} x?gQ\ 0S<  
for(int i=0;i<nEndPos.length-1;i++) *cPN\Iu.W  
{ \D ^7Z97  
nEndPos = nStartPos[i+1]; ^t7_3%%w  
} Gg}t-_M  
nEndPos[nEndPos.length-1] = nFileLength; t)KPp|&  
} 1S&0  
} shD+eHo$  
$8=(I2&TW  
5e)i!;7Uv  
//启动子线程 k}#@8n|b  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0xLkyt0  
for(int i=0;i<nStartPos.length;i++) 3#B@83C0Z  
{ X&/(x  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r<v_CFJ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), JOPTc]  
nStartPos,nEndPos,i); F~%|3a$Y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0:jsV|5B8  
fileSplitterFetch.start(); $@68=  
} t Z+0}d  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .a5X*M]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); } mgVC  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \6U 2-m'  
nEndPos = " + nFileLength); 80dSQ"y  
// fileSplitterFetch[nPos.length-1].start(); 4^0\dq  
`..EQ BM  
wQ@Zw bx  
//等待子线程结束 rYD']%2  
//int count = 0; 3Sk5I%  
//是否结束while循环 DZ,<Jmg&e*  
boolean breakWhile = false; wE)] ah:  
%s]U@Ku(a  
w' .'Yu6  
while(!bStop) Ct-rD79l  
{ .vN)A *  
write_nPos(); !'+\]eA  
Utility.sleep(500); X #&(~1O  
breakWhile = true; p!C_:Z5i  
QziN]  
O}e|P~W  
for(int i=0;i<nStartPos.length;i++) KsZ@kTs  
{ A{G5Plrh  
if(!fileSplitterFetch.bDownOver) =`rppO  
{ :P HUsy  
breakWhile = false; &t[z  
break; `\Uc4lRS  
} Z83q-  
} &8pCHGmV)  
if(breakWhile) [lmHXf@1C  
break; MA~|y_V  
XYz,NpK  
nh _DEPMq  
//count++; Gw{Gt]liq  
//if(count>4) >lUBt5gU  
// siteStop(); &*Q|d*CP  
} aeN }hG  
{JCSR2BB  
`V?x xq\  
System.err.println("文件下载结束!"); QCZ,K" y  
} R[mH35D/  
catch(Exception e){e.printStackTrace ();} <Tj"GVZAEO  
} 0X ] ekq  
Co{MIuL  
I!C(K^  
//获得文件长度 ;oN{I@}k  
public long getFileSize() ]# tGT0   
{ 8:3oH!n  
int nFileLength = -1; [TiT ff&LV  
try{ SX1Fyy6 w  
URL url = new URL(siteInfoBean.getSSiteURL()); ;o~+2Fir  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P#vv+]/  
httpConnection.setRequestProperty("User-Agent","NetFox"); >/ *?4  
k1QpX@  
>oM9~7f  
int responseCode=httpConnection.getResponseCode(); ')1}#V/I  
if(responseCode>=400) oo$WD6eCR  
{ ?3B t ;<^  
processErrorCode(responseCode); Z9 ;nC zHm  
return -2; //-2 represent access is error e)ZyTuj  
} #T gz,e9  
Egjk^:@  
c Eh0Vh-]  
String sHeader; _{2Fx[m%  
o2 T/IJP  
|p=.Gg=2  
for(int i=1;;i++) tF;& x g  
{ zd6Qw-D7x  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 84hi, S5P  
//Utility.log(in.readLine()); ^t/'dfF  
sHeader=httpConnection.getHeaderFieldKey(i); M&}oat*  
if(sHeader!=null) %z!d4J75  
{ WacU@L $A  
if(sHeader.equals("Content-Length")) 7(+OsE  
{ Eezlx9b  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); -Fok %iQ'5  
break; K[Egwk7  
} XEgx#F ;F  
} vP87{J*DE1  
else 1"4nmw}  
break; <g/(wSl  
} CL<KBmW7  
} =?`y(k4a  
catch(IOException e){e.printStackTrace ();} sBuq  
catch(Exception e){e.printStackTrace ();} "M5ro$qZ}  
r:8]\RU  
*k@0:a(>  
Utility.log(nFileLength); D<D k1  
?V\9,BTb)  
D"( 3VIglq  
return nFileLength; }G,SqpcG  
} [-:<z?(n4  
5>4A}hSe  
23u1nU[0  
//保存下载信息(文件指针位置)  z7.C\l  
private void write_nPos() 0imqj7L  
{ 13>3R+o  
try{ ^b|Nw:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4-}A'fTU8  
output.writeInt(nStartPos.length); "ZJ1`R=Mj  
for(int i=0;i<nStartPos.length;i++) WT ~dA95  
{ 2 Zjb/  
// output.writeLong(nPos); 9^ *ZH1  
output.writeLong(fileSplitterFetch.nStartPos); 1A/c/iC  
output.writeLong(fileSplitterFetch.nEndPos); SFk11  
} (HV~ '5D  
output.close(); 2cX"#."5p  
} ?C>VB+X}y  
catch(IOException e){e.printStackTrace ();} Sfr\%Buv  
catch(Exception e){e.printStackTrace ();} Y5A~iGp8E  
} }Cq9{0by?a  
+VpE-X=T  
T.m)c%]^/  
//读取保存的下载信息(文件指针位置) <{z3p:\  
private void read_nPos() @|UIV  
{ v YmtpKNj%  
try{ 5dNf$a0E  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  eS@!\H x  
int nCount = input.readInt(); s*~jvL  
nStartPos = new long[nCount]; <sWcS; x  
nEndPos = new long[nCount]; .L(j@I t  
for(int i=0;i<nStartPos.length;i++) l^eNZ3:H  
{ bmq XP  
nStartPos = input.readLong(); 2}#wd J`  
nEndPos = input.readLong(); `Py= ?[cD  
} +8vzkfr3It  
input.close(); [sY1|eX   
} R#Nd|f<  
catch(IOException e){e.printStackTrace ();} /%q9hI   
catch(Exception e){e.printStackTrace ();} :mtw}H 'F8  
} QVRokI`BF  
Iv|WeSL.  
0*:hm%g  
private void processErrorCode(int nErrorCode) .lF\bA|  
{ r5qx! >  
System.err.println("Error Code : " + nErrorCode); AoOG[to7  
} Ho._&az9cT  
*I1W+W`G  
B[_bJ *  
//停止文件下载 Qx,$)|_  
public void siteStop() llG#nDe  
{ I7z]%Z  
bStop = true; Q]g4gj  
for(int i=0;i<nStartPos.length;i++) [dF=1E>W_J  
fileSplitterFetch.splitterStop(); }:D~yEP  
<VxpMF  
e%c5 OZ3~  
} *_K-T#  
} ?N?pe}  
//负责部分文件的抓取  t-x"(  
**FileSplitterFetch.java ST8/ ;S#c  
*/ Jx>B %vZ\  
package NetFox; H!>oLui  
j.N\U#3KK  
pfQZ|*>lkb  
import java.io.*; Qp.!U~  
import java.net.*; Aag)c~D  
v*fc5"3eO  
/FV6lR!0^  
public class FileSplitterFetch extends Thread { Z#:@M[HH{  
_ * s  
vMdhNOU  
String sURL; //File URL 2&K|~~  
long nStartPos; //File Snippet Start Position K}/`YDu  
long nEndPos; //File Snippet End Position GhQ`{iJM  
int nThreadID; //Thread's ID X6*y/KG N  
boolean bDownOver = false; //Downing is over e27CbA{_w  
boolean bStop = false; //Stop identical c%/&@vs7  
FileAccessI fileAccessI = null; //File Access interface PyxN_agf  
RYJc>  
54cgX)E[x  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException \lIHC{V\  
{ 2LH;d`H[0  
this.sURL = sURL; |=}~>!!  
this.nStartPos = nStart; ',s7h"  
this.nEndPos = nEnd; ?F!J@Xn5  
nThreadID = id; 35kbE'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 by<@Zwtf  
} !;C(pnE  
n]c,0N  
iSLf:  
public void run() 2co{9LM  
{ ayz1i:Q|  
while(nStartPos < nEndPos && !bStop) t\d;}@bl  
{ ~EkGG .  
>,vW  
GJfNO-  
try{ T\CQ  
URL url = new URL(sURL); '^3pF2lIw  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ']e4 !  
httpConnection.setRequestProperty("User-Agent","NetFox"); `|?$; )  
String sProperty = "bytes="+nStartPos+"-"; b=\3N3OX  
httpConnection.setRequestProperty("RANGE",sProperty); F ) ~pw  
Utility.log(sProperty); ]JuB6o_L  
>M85xjXP  
'6J$X-  
InputStream input = httpConnection.getInputStream(); I19F\ L`4  
//logResponseHead(httpConnection); bO3KaOC8N  
*]?YvY  
Y,}43a0A  
byte[] b = new byte[1024]; 1RHH<c%2n  
int nRead; Xb 1^Oj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) &scD)  
{ 2dW-WHaM  
nStartPos += fileAccessI.write(b,0,nRead); xmd$Jol^  
//if(nThreadID == 1) 58U[r)/  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); I3b-uEHev  
} bGO_y]Pc  
d0E5;3tQ  
:u93yH6~8  
Utility.log("Thread " + nThreadID + " is over!"); _Fy:3,(  
bDownOver = true; F$p,xFH#  
//nPos = fileAccessI.write (b,0,nRead); baGI(Dk  
} G=Bj1ss.  
catch(Exception e){e.printStackTrace ();} S]@iS[|?  
} u)>*U'bM  
} k5CIU}H"  
W7> _nK+g?  
:$d3a"]  
//打印回应的头信息 cu|q &  
public void logResponseHead(HttpURLConnection con) ]HT>-Ba;{h  
{ h0}-1kVT^  
for(int i=1;;i++) m':m`,c!  
{ $7g(-W  
String header=con.getHeaderFieldKey(i); #R| 4(HlL  
if(header!=null) &_gmQ;%t:  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); {a%cU[q  
Utility.log(header+" : "+con.getHeaderField(header)); ^>uGbhBp  
else c~;.m<yrf  
break; 3qZ{yr2N[  
} >.>5%  
} rMloj8O*  
u?/]"4  
]z NL+]1_  
public void splitterStop() V^5 t~)#46  
{ 1-<Xi-=^{t  
bStop = true; AlV2tffY^  
} qIp`'.#m  
dq&d>f1  
'KG`{K$  
} (>23[;.0  
E ..[F<5  
y0^FTSQ|  
/* :#;?dMkTY  
**FileAccess.java `dhK$jYD  
*//文件访问(定位,写) fRmc_tx  
package NetFox; .=S{  
import java.io.*; p6*D^-  
I&0yUhn  
2(|V1]6D?  
public class FileAccessI implements Serializable{ ;?9~^,l  
u@Lu.t!],  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >LSA?dy!?  
RandomAccessFile oSavedFile; !JA63  
long nPos; suwj1qYJ4  
j!/(9*\  
k:.c(_2M  
public FileAccessI() throws IOException Sl#XJ0 g  
{ 1GxYuTZ{  
this("",0); /uVB[Tk^  
} .^,vK7  
xM,3F jF  
ORTM [cL  
public FileAccessI(String sName,long nPos) throws IOException t z{]H9  
{ a@. /e @p  
oSavedFile = new RandomAccessFile(sName,"rw"); mB\|<2  
this.nPos = nPos; (;h\)B!o  
oSavedFile.seek(nPos);  xMU)  
} xXtDGP  
wpvaTHo  
Jor?;qo3  
public synchronized int write(byte[] b,int nStart,int nLen) .:0nK bW  
{ RK0IkRXQd  
int n = -1; V/Tp&+Z.c  
try{ aw`mB,5U  
oSavedFile.write(b,nStart,nLen); 8b/yT4f  
n = nLen; -T>`PJpJuL  
} @`{UiTN X`  
catch(IOException e) Q. >"@c[  
{ UcZ3v]$I  
e.printStackTrace (); uf6{M_jXZ  
} Y9u2:y!LdL  
p0/I}n4<5n  
Vy biuP  
return n; l\eq/yg_  
} R] dB Uu  
X qh+  
D_{J:Hb  
} {5*5tCIt  
q7;)&_'  
3^Ex_jeB  
/* ~7*HZ:.  
**SiteInfoBean.java ,J[sg7v cv  
*/ =3@^TW(j  
package NetFox; y ^YrGz.  
R_lNC]b0  
_K8-O>I "  
public class SiteInfoBean { IL<5Suz:  
:%Bo)0a9  
P iN3t]2  
private String sSiteURL; //Site's URL 6>l-jTM  
private String sFilePath; //Saved File's Path ?p5Eo{B  
private String sFileName; //Saved File's Name `jJb) z3D  
private int nSplitter; //Count of Splited Downloading File Y$N|p{Z  
(T@ov~ @  
HLS^Ga,(  
public SiteInfoBean() %K zURv  
{//nSplitter的缺省值为5 bBZvL  
//default value of nSplitter is 5 9Y7 tI3  
this("","","",5); ALFw[1X  
} wc;5tb#  
S"lcePN  
ioZ2J"s  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) <)M?qkjb  
{ 7n#0eska,  
sSiteURL= sURL; R (6Jvub"I  
sFilePath = sPath; k(s3~S2h  
sFileName = sName; U\51j  
this.nSplitter = nSpiltter; &fW;;>  
&vLZj  
fz:F*zT1  
} g|W~0A@D  
Bs^W0K$uBO  
uu(.,11`  
public String getSSiteURL() D@mDhhK_  
{ $?0<rvGJ  
return sSiteURL; %!WQ;(  
} %e3lb<sv6  
2f4*r^  
 Q}G   
public void setSSiteURL(String value) gp;(M~we  
{ z. 7 UfLV9  
sSiteURL = value; @T1-0!TM')  
} Q7i^VN  
X^"95Ic  
(R.k.,z  
public String getSFilePath() $.v5G>- )3  
{ @UD6qA  
return sFilePath; ZQ@^(64  
} ([s2F%S`@  
?"J5~_U.  
+i{&"o4}  
public void setSFilePath(String value) KWM.b"WnXr  
{ b>G!K)MS3  
sFilePath = value; DLf6D | "  
} Z#d_<e?  
M7UVL&_z%  
_bFX(~37z?  
public String getSFileName() Zb3E-'G+  
{ :*Sl\:_X)  
return sFileName; RKRk,jRL  
} v cqL  
jR*1%.Ng  
9CW .xX8  
public void setSFileName(String value) 1NA>W   
{ t4 $cMf  
sFileName = value; q^k6.5*"  
} ,253'53W)  
9tqX77UK  
ga0W;Vq&X  
public int getNSplitter() , En D3 |  
{ N(6|TE2  
return nSplitter; 6imDA]5N&  
} 3/P2&m  
OV^) N  
PudwcP {  
public void setNSplitter(int nCount) [iB`- dE,  
{ cC b'z1  
nSplitter = nCount; ,accw}G  
} nu|;(ly  
} 4ijoAW3A^  
ney6N@  
Gd%KBb  
/* q>?uB4>^  
**Utility.java fMP$o3;  
*/ tFO86 !ln  
package NetFox; vrLI`3n]  
Tz:mj  
grp1nWAs  
public class Utility { "~> # ;x{  
58ev (f  
%\Z{~(&-v  
public Utility() IhhB^E|  
{ BRhAL1  
_r^Cu.[7  
7?Q<kB=f  
} eZ8~t/8  
i*_T\_=  
//线程睡眠 t6W$t  
public static void sleep(int nSecond) /n"Ib )M  
{ _ )b:F=4j  
try{ Wz`MEyj  
Thread.sleep(nSecond); "d^hY}Xx  
} Tky\W%Ag  
catch(Exception e) F]:@?}8R  
{ y 4j0nF  
e.printStackTrace (); .BuXg<`  
} 1\X1G>60m  
} dj3}Tjt  
&!x!j ,nT  
//日志 8!(4;fN$j.  
public static void log(String sMsg) 7 ^>UUdk(  
{ [7]Kvb2t  
System.err.println(sMsg); ^rO3B?_  
} @doo2qqIe]  
38ChS.(  
zZ@]Kq;.s  
public static void log(int sMsg) ]@wee08  
{ '85@U`e.  
System.err.println(sMsg); y9kydu#q  
} $k5mI1~  
} 65X$k]x  
?=}~]A5N  
E2+x?Sc+  
/* 2Z!%Q}Do  
**TestMethod.java f mXU)  
*/ {ULyB$\-  
package NetFox; aZ"9)RJe  
{y-7xg~}  
6EfGJq  
public class TestMethod { a"ZBSg(  
1n|)05p  
>U?HXu/TJr  
public TestMethod() j5QS/3  
{ ///xx/weblogic60b2_win.exe R-CFF  
try{ G$FNofQx  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); MDI[TNYG  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ozv:$>v@"  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Huzw>  
fileFetch.start(); M`^;h:DN^  
} DWT4D)C,U  
catch(Exception e){e.printStackTrace ();} TNs ;#Q  
rN* , U\q  
AT.WXP0$A  
} 0tV"X  
"uK`!{  
2\ 3}y(  
public static void main(String[] args) LU "e9  
{ a:nMW'!  
new TestMethod(); QQ*yQ\  
} E07g^y"}i  
} p<%76H A  
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