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http断点续传简单实现(java)

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/* \xOYa  
**SiteFileFetch.java ;|=5)KE  
*/ (CDh,ZN;|  
package NetFox; =s AOWI,8!  
import java.io.*; 7F]oK0l_  
import java.net.*; -iy17$  
3-y2i/4}$  
V 7 p{'C   
public class SiteFileFetch extends Thread { rk+s[Qi~  
9~ V(wG  
ty;a!yjC  
SiteInfoBean siteInfoBean = null; //文件信息Bean }q_Iep  
long[] nStartPos; //开始位置 G"J 8i|~  
long[] nEndPos; //结束位置 <YG 42,N  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /L`qOr2E  
long nFileLength; //文件长度 i @M^l`w  
boolean bFirst = true; //是否第一次取文件 , Sf:R4=  
boolean bStop = false; //停止标志 c#9=o;1El  
File tmpFile; //文件下载的临时信息 j`u2\ ;  
DataOutputStream output; //输出到文件的输出流 D(_j;?i  
gT fA]  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) <@>icDFEHn  
public SiteFileFetch(SiteInfoBean bean) throws IOException gBgaVG  
{ G #$r)S  
siteInfoBean = bean; tR=1.M96Y  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =?M{B1;H  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ?YFSK  
if(tmpFile.exists ()) o|KmKC n>  
{ Fyz1LOH[X  
bFirst = false; UZJs!#P  
read_nPos(); m 2%  
} 41C6ey  
else gf;B&MM6  
{ fob.?ID-;  
nStartPos = new long[bean.getNSplitter()]; &)Vuh=  
nEndPos = new long[bean.getNSplitter()]; T~lHm  
} _y[B/C,q  
#cl|5jm+m#  
IjPt JwW`A  
QF.M%she+  
} _Pw5n mH c  
R,hwn2@B  
qpB8ujj<V  
public void run() /u"K`y/*j\  
{ /KgP<2p  
//获得文件长度 '8^>Z.~V  
//分割文件 fQfd1=4  
//实例FileSplitterFetch 5'rP-z~ u  
//启动FileSplitterFetch线程 P1qnU  
//等待子线程返回 AhV V  
try{ P#KT lH  
if(bFirst) mnYzn[d3U  
{ R"`<ZY6(Ou  
nFileLength = getFileSize(); 0$R}_Ok  
if(nFileLength == -1) Nk\/lK\  
{ I~M@v59C  
System.err.println("File Length is not known!"); F{17K$y  
} X5)].[d  
else if(nFileLength == -2) yEL5U{  
{ 2reQd47  
System.err.println("File is not access!"); t] G hONN  
} bmRp)CYd  
else XJ1<!tl  
{ Vg`32nRN  
for(int i=0;i<nStartPos.length;i++) > 8!9  
{ a [BIY&/Q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); QlnI&o  
} $=!_ !tr  
for(int i=0;i<nEndPos.length-1;i++) OLJ|gunA#  
{ H1ox>sC  
nEndPos = nStartPos[i+1]; UDgUbi^v|D  
} G $iC@,/  
nEndPos[nEndPos.length-1] = nFileLength; V(!-xu1,  
} )K 0rPnYV  
} 8{%[|Ye  
?h-:,icR  
$2v{4WP7G  
//启动子线程 ftqeiZ 2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; fXx !_Z  
for(int i=0;i<nStartPos.length;i++) 2$> <rB  
{ tb'O:/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Z-'xJq  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "&TN}SBW  
nStartPos,nEndPos,i); wn>?r ?KIB  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); lDtl6r/  
fileSplitterFetch.start(); )cRP6 =  
} 1NU@k6UHl  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }ILg_>uq[  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $s9YU"  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "xMnD(p  
nEndPos = " + nFileLength); ,uhOf! |  
// fileSplitterFetch[nPos.length-1].start(); zqGo7;;#  
uRRp8hht  
$mDlS  
//等待子线程结束 OO?BN!  
//int count = 0; _Dg|Iz,Uh  
//是否结束while循环 Pu0O6@Rg  
boolean breakWhile = false; I(0 *cWO  
a*UxRi8  
!L55S 0 3  
while(!bStop) )tR@\G>%  
{ sy+tLDMd  
write_nPos(); %1PNP<3r0  
Utility.sleep(500); :J;*]o:  
breakWhile = true; {$qLMx';  
+m1y#|08  
v^Pjvv=  
for(int i=0;i<nStartPos.length;i++) LLW\1 cxi  
{ r| 0wIpi6Q  
if(!fileSplitterFetch.bDownOver) :"~n` Q2[  
{ C1SCV^#  
breakWhile = false; $n9Bp'<  
break; {-e|x&-  
} KIHr%  
} ^@AIXBe  
if(breakWhile) ]c$)0O\O  
break; 0X4%Ccs  
[<A|\d'x  
QMWDII&t  
//count++; 4A~1Z,"%v(  
//if(count>4) S,2{^X  
// siteStop(); A\};^Y  
} & 0%x6vea  
LIMPWw g  
^Y+P(o$HM  
System.err.println("文件下载结束!"); vvcA-k?  
} 85]3y%f9  
catch(Exception e){e.printStackTrace ();} j21nh> d  
} H D{2nZT  
VF] ~J=>i  
^,N=GZRWW  
//获得文件长度 dG*2-v^G  
public long getFileSize() ~jn~M_}K  
{ 4ROuy+Ms'  
int nFileLength = -1; Q\[2BJo/  
try{ 8k -l`O~  
URL url = new URL(siteInfoBean.getSSiteURL()); ^Jdji:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ' lMPI@C6r  
httpConnection.setRequestProperty("User-Agent","NetFox"); `\5u/i'Ca!  
+*ZF52hy|  
6-h(305A  
int responseCode=httpConnection.getResponseCode(); u:s[6T0  
if(responseCode>=400) 7xy[;  
{ 1;N5@0%p  
processErrorCode(responseCode); E [b6k&A  
return -2; //-2 represent access is error 1|/]bffg!c  
} iF'qaqHWY4  
tw%z!u[a  
tg' 2 v/  
String sHeader; S{F'k;x/5  
U%E364;F  
)xj!7:n)  
for(int i=1;;i++)  ]pP:  
{ )r.4`5Rc  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); QO(P_az3mg  
//Utility.log(in.readLine()); 5Cjh%rj(jl  
sHeader=httpConnection.getHeaderFieldKey(i); >7I"_#x1:  
if(sHeader!=null) k86j& .m_  
{ 55#s/`gd)^  
if(sHeader.equals("Content-Length")) B~t[Gy  
{ ?0k4l8R  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); lzup! `g  
break; TuX9:Q  
} Rt2<F-gY  
} k9vzxZ%s:  
else m6^n8%  
break; !,zRg5Wp4  
} TW5Pt{X= f  
} \zGmZZ  
catch(IOException e){e.printStackTrace ();} f?|cQ[#t!\  
catch(Exception e){e.printStackTrace ();} q}0xQjpo  
@<,YUp,%S  
b'$fr6"O1  
Utility.log(nFileLength); q7u bRak  
oVYW '~OID  
)=@ SA`J  
return nFileLength; =9y&j-F  
} 6A,-?W'\  
7\nR'MOZ  
Tq*K =^  
//保存下载信息(文件指针位置) t2 0Es  
private void write_nPos() 40)Ti  
{  4fa2_  
try{ Qy_! +q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S<bsrS*$  
output.writeInt(nStartPos.length); ;j^C35  
for(int i=0;i<nStartPos.length;i++) vm Y*K  
{ 1NQstmd{  
// output.writeLong(nPos); JuTIP6 /G  
output.writeLong(fileSplitterFetch.nStartPos); Hm*?<o9mxC  
output.writeLong(fileSplitterFetch.nEndPos); O[O[E}8#  
} i]M:ntB"  
output.close(); * j]"I=D  
} X[r\ Qa  
catch(IOException e){e.printStackTrace ();} '|^<|S_+K  
catch(Exception e){e.printStackTrace ();} i_M0P12  
} ~rICPR  
[+4/M3J%  
$:D-dUr1  
//读取保存的下载信息(文件指针位置) rI.CCPY~s  
private void read_nPos() GB\1'  
{ h#Q Sx@U6  
try{ BA(PWX`H  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); lZf=#  
int nCount = input.readInt(); =LHz[dSL  
nStartPos = new long[nCount]; _,{R3k  
nEndPos = new long[nCount]; k2Y *  
for(int i=0;i<nStartPos.length;i++) S"skKh4w  
{ w9Z,3J6r  
nStartPos = input.readLong(); FvVR \a  
nEndPos = input.readLong(); N~t4qlC/  
} %MH!L2|  
input.close(); ^a{cK  
} CE;J`;  
catch(IOException e){e.printStackTrace ();} CP"  
catch(Exception e){e.printStackTrace ();} vS'l@`Eg]  
} t`oH7)nut  
j'M=+  
(>a8h~Na  
private void processErrorCode(int nErrorCode) ywj'S7~A  
{ \mGo k<b4  
System.err.println("Error Code : " + nErrorCode); 5,Hj$v7fe  
} >IFqwh7b  
3:~ *cU  
%=EN 3>,  
//停止文件下载 m(o^9R_=^9  
public void siteStop() "nQ&~KQ  
{ lz >>{  
bStop = true; )E>nr Z  
for(int i=0;i<nStartPos.length;i++) <yxy ;o  
fileSplitterFetch.splitterStop(); K 0Gm ?(  
6Ud6F t6  
{$fd?| 9h  
} l`k""f69W  
} (N 0kTi]b  
//负责部分文件的抓取 gof'NT\c  
**FileSplitterFetch.java 7x5wT ?2W  
*/ JNk6:j&Pf  
package NetFox; yHNx,ra   
)g ; !IL  
7wB*@a-  
import java.io.*; H{CiN  
import java.net.*; L-z9n@=8\  
Gw1Rp  
.bloaeu-  
public class FileSplitterFetch extends Thread { :Cdqj0O3u  
pb5q2|u`h  
S<nf"oy_K  
String sURL; //File URL "f|xIK`c  
long nStartPos; //File Snippet Start Position wpI_yp  
long nEndPos; //File Snippet End Position vtu!* 7m  
int nThreadID; //Thread's ID Y6w7sr_R  
boolean bDownOver = false; //Downing is over Wv7hY"  
boolean bStop = false; //Stop identical }{y(&Oy3Y  
FileAccessI fileAccessI = null; //File Access interface 7*I:cga  
2.PZtl  
OLs<]0H  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException K);)$8K  
{ =%Z5"];  
this.sURL = sURL; A\:u5(  
this.nStartPos = nStart; c%x9.s<+1  
this.nEndPos = nEnd; 1];OGJuJ2  
nThreadID = id; .4O~a  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "HwSW4a]  
} qayM 0i>>  
7I4<Dj  
o>i@2_r\&H  
public void run()  TnXx;v  
{ a4E{7c  
while(nStartPos < nEndPos && !bStop) Xt9vTCox  
{ 7,7-E&d  
Or3GrZ!H  
tQWjNP~  
try{ -|g9__|@  
URL url = new URL(sURL); )kk10AZV-E  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Bj*\)lG<  
httpConnection.setRequestProperty("User-Agent","NetFox"); qac8zt#2 C  
String sProperty = "bytes="+nStartPos+"-"; {v>8Kp7_R  
httpConnection.setRequestProperty("RANGE",sProperty); GJTakhj3  
Utility.log(sProperty); P1qQ)-J  
aGbHDo  
J|=0 :G  
InputStream input = httpConnection.getInputStream(); 5`\"UC7?%  
//logResponseHead(httpConnection); L"Dos +  
dKJ-{LV  
M'|?* aNK  
byte[] b = new byte[1024]; !=bGU=^  
int nRead; 4H*M^?h\#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) h-+vN hH  
{ V:<Z   
nStartPos += fileAccessI.write(b,0,nRead); >QSlH]M  
//if(nThreadID == 1) 9!?Ywc>0#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7xh91EU:4  
} iBh.&K{j  
AkAQ%)6qV  
Iq@&?,W  
Utility.log("Thread " + nThreadID + " is over!"); KD^n7+w%  
bDownOver = true; @fh:lsw  
//nPos = fileAccessI.write (b,0,nRead); LMHii Os,  
} w`I+ 4&/h  
catch(Exception e){e.printStackTrace ();} A{%LL r:  
} a&Z;$  
} Bg.  
Oj8xc!d'  
Dp-j(F  
//打印回应的头信息 q#PMQR"C  
public void logResponseHead(HttpURLConnection con) u9u'!hAGH  
{ V>(>wSR  
for(int i=1;;i++) nq qqP  
{ k7kPeq  
String header=con.getHeaderFieldKey(i); }uiD8b{I  
if(header!=null) au#/Q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); wK!7mZ  
Utility.log(header+" : "+con.getHeaderField(header)); }fZ~HqS2w  
else P!u0_6  
break; g&r3 ;  
} 5Zuk`%O  
} ^GnR1.ux  
IC:>60A,]  
+FH@|~^O  
public void splitterStop() V='A;gs  
{ #`@5`;U>#  
bStop = true; ov\+&=IRG  
} oq9gFJG(  
&G)/i*  
nSp OTQ  
} V;d<S@$  
rEwd76?  
Zx Ak  
/* _[h!r;DsG  
**FileAccess.java t~%(Zu>S  
*//文件访问(定位,写) q}gM2Ia'vY  
package NetFox; ${{[g16X  
import java.io.*; WI1DL&*B@<  
snP]&l+  
N{H#j6QW  
public class FileAccessI implements Serializable{ q{l %k  
2 $Umqt  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *X uIA-9  
RandomAccessFile oSavedFile; 3,0b<vfSv  
long nPos; MDCwgNPiQW  
>Z>s R0s7  
^B$cfs@*  
public FileAccessI() throws IOException M^{=&  
{ n(#[[k9&Ic  
this("",0); 49=L9:  
} Nz>xilU'  
|]eWO#vs  
h{: ]'/@~  
public FileAccessI(String sName,long nPos) throws IOException tuJ{IF  
{ kTA4!654  
oSavedFile = new RandomAccessFile(sName,"rw"); %wco)2  
this.nPos = nPos; \$!D^%~;  
oSavedFile.seek(nPos); umN4|X  
} xoQ(GrBY  
7LsVlT[  
U#`2~Qv/1  
public synchronized int write(byte[] b,int nStart,int nLen) D*'sOB(  
{ B\tm  
int n = -1; tA^CuJR  
try{ l[^0Ik-G  
oSavedFile.write(b,nStart,nLen); Q_`EKz;N{  
n = nLen; :}CcWfbT  
} T%aM~dp  
catch(IOException e) _k#!^AJ}x  
{ K"zRj L+  
e.printStackTrace (); gF:| j(  
} qq"0X! w  
=1\mLI}@  
0|ekwTx.  
return n; fo~>y  
} '4}8WYKQ  
+1^L35\@  
y?Pw6;e.  
} {a ]u  
4'"WD0  
=R)w=ce  
/* 8?ip,Q\  
**SiteInfoBean.java 9\uBX.]x  
*/ [#%@,C  
package NetFox; Sa@T#%oU  
I~4!8W-Y  
?kS#g  
public class SiteInfoBean { `A<2wd;  
K{:[0oIHc  
LTuT"}dT[  
private String sSiteURL; //Site's URL % CQv&d2  
private String sFilePath; //Saved File's Path  r}}2 Kl  
private String sFileName; //Saved File's Name !6hV|2aJy  
private int nSplitter; //Count of Splited Downloading File sl:1P^b  
K^P&3H*(/n  
:i|Bz6Ht4  
public SiteInfoBean() v8zOY#?  
{//nSplitter的缺省值为5 LtPaTe  
//default value of nSplitter is 5 Hc-up.?v'v  
this("","","",5); q2/kegAT  
} }*S`1IWMj  
c]"w0a-`^@  
j /@<=  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) tJ .Ln  
{ ;*hVAxs1  
sSiteURL= sURL; jhJ<JDJ?`  
sFilePath = sPath; '(-H#D.oy'  
sFileName = sName; ez~u A4  
this.nSplitter = nSpiltter; IaK J W?  
#Z,@yJ2wl  
dptfIBYc+  
} !x! 1H5"  
bXA%|7*  
K"ly\$F  
public String getSSiteURL() @>&b&uj7T  
{ x~F YG  
return sSiteURL; 7a=ul:  
} O:ACp<@  
">Ms V/  
G cB<i  
public void setSSiteURL(String value) Zu 4au<  
{ KGc!#C  
sSiteURL = value; cj[x%eK>  
}  smn~p/u  
MI-S}Qoe  
@bChJl4  
public String getSFilePath() v+o6ZNX  
{ '}:(y$9.`  
return sFilePath; ].sD#~L_  
} C-g,uARX(r  
/1_O5'5+v  
wPq9`9 #  
public void setSFilePath(String value) .hUlI3z9  
{ ,3!TyQ \m'  
sFilePath = value; %:j`%F;R  
} 9W, %[  
j& ykce  
f$vU$>+[  
public String getSFileName() rjj_]1?K  
{ ;- _ZWk]  
return sFileName; %gWQ}QF  
} MNp4=R  
AMASh*  
KzQFG)q,  
public void setSFileName(String value) y:_>R=sw  
{ d c/^  
sFileName = value; RJKi98xwJ  
} rITA-W O  
1K(mdL{m5  
*!E~4z=  
public int getNSplitter() fs-LaV 0  
{ tx)$4v  
return nSplitter; R0mkEM  
} j<`3xd'  
`VvQems  
8(\J~I[^  
public void setNSplitter(int nCount) 7SNdC8GZ~  
{ lBm`W]3T  
nSplitter = nCount; 3,2$Ny3N  
} w'XN<RWA  
} j\zlp  
Z9|A"[b  
s0:M'wA  
/* 9JX@c k  
**Utility.java 7GS 4gSd3  
*/ 1hSV/%v_  
package NetFox; Z>3m-:-e  
1.PN_9%  
?\(qA+iP0  
public class Utility { m*YfbOhs#  
,k*%=TF7N  
FBvh7D.hV  
public Utility()  \S1W,H|  
{ ZJm$7T)V  
$M/1pZ  
8 nL9#b  
} SlHDBr!.z  
t0r0{:  
//线程睡眠 +@yU `  
public static void sleep(int nSecond) g-B{K "z  
{ g^x=y  
try{ ^2{6W6=  
Thread.sleep(nSecond); (h@!_qi9:  
} /y|ZAN  
catch(Exception e) 2`j{n \/  
{ A{M7   
e.printStackTrace (); N%ccy?B  
} d R=0K  
} qL`yaU  
ZI1*Cb  
//日志 }fv7WhQ  
public static void log(String sMsg) !uO@4]:Y  
{ ~j(vGO3JB  
System.err.println(sMsg); 87W!R<G  
} u;!h   
bsr]Z&9rrk  
:I7mM y*  
public static void log(int sMsg) `& h-+  
{ R*0mCz^+h  
System.err.println(sMsg); ,zr,>^ v  
} .tppCy  
} 0rz1b6F5,  
*po o.Zz  
Km!ACA&s6  
/* iSR"$H{  
**TestMethod.java BFhEDkk  
*/ nB5\ocJ  
package NetFox; \13Q>iAu  
*3!r &iY  
w!v^6[!  
public class TestMethod { NZa 7[}H  
`(`-S md  
68(^*  
public TestMethod() cruBJZr*  
{ ///xx/weblogic60b2_win.exe =:zPT;K  
try{ x X[WX#'f  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); HFTeG4R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); b/Ma,}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z wRF-{s  
fileFetch.start(); LI25VDZ|iP  
} &BNlMF  
catch(Exception e){e.printStackTrace ();} sD2,!/'  
v\MQ?VC  
NZ&ZK@h}.  
} ao=e{R)  
mqHH1}  
`LLmdm 6i  
public static void main(String[] args) /5z,G r  
{ " DLIx}  
new TestMethod(); 5c(g7N  
} " C&>$h_%  
} Lwx J:Kz.  
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