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http断点续传简单实现(java)

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/*  ~ Dvxe  
**SiteFileFetch.java G&qO{" Js  
*/ Y*0AS|r!  
package NetFox; c^$_epc*  
import java.io.*; /'KCW_Q  
import java.net.*; z|,YO6(L  
0X6|pC~  
D; xRgHn  
public class SiteFileFetch extends Thread { WE;QEA/  
hKa<9>MI`  
@'UbTB!  
SiteInfoBean siteInfoBean = null; //文件信息Bean Q+L;k R  
long[] nStartPos; //开始位置 CJ+/j=i;~c  
long[] nEndPos; //结束位置 f;os\8JdM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 {C+blzh6  
long nFileLength; //文件长度 _}8hE v  
boolean bFirst = true; //是否第一次取文件 7K"{}:  
boolean bStop = false; //停止标志 1Pya\To,m  
File tmpFile; //文件下载的临时信息 kg0X2^#b  
DataOutputStream output; //输出到文件的输出流 o< )"\f/,  
S#km`N`  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Ht >5R  
public SiteFileFetch(SiteInfoBean bean) throws IOException bYs K|n  
{ gumT"x .^  
siteInfoBean = bean; 4yOYw*X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); \YXzq<7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !4"(>Rnw  
if(tmpFile.exists ()) <%d/"XNg[D  
{ c~1+5&  
bFirst = false; (i..7B:  
read_nPos(); HW|5'opF  
} c lhmpu  
else Q,pnh!.-c  
{ -"Mq<XO&51  
nStartPos = new long[bean.getNSplitter()]; e@6]rl  
nEndPos = new long[bean.getNSplitter()]; l', +l{\Z  
} EJAk'L+nuH  
aCxF{>n  
D\13fjjHlu  
q!L@9&KAQ  
} ]iI2  
CGyw '0S  
Sj=x.Tr\  
public void run() Nuc;Y  
{ j p"hbV  
//获得文件长度 zx #HyO[a  
//分割文件 7'IcgTWDZy  
//实例FileSplitterFetch h7 r *5E  
//启动FileSplitterFetch线程 7+(on  
//等待子线程返回 hQWo ]WF(J  
try{ Z;v5L/;  
if(bFirst) 9w)W|9  
{ sej$$m R  
nFileLength = getFileSize(); /)+V(Jlu  
if(nFileLength == -1) qdW"g$fW  
{ + *xi&|%  
System.err.println("File Length is not known!"); .ei5+?V<i  
} RIm8PV;N  
else if(nFileLength == -2) -eE r|Gs)  
{ $U/|+*  
System.err.println("File is not access!"); M6nQ17\{  
} WilKC|R]P  
else {>v5~G  
{ =Ch^;Wyt  
for(int i=0;i<nStartPos.length;i++) ]z77hcjB1  
{ rp&XzMwC4  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); W(#u^,$e[  
} mz>GbImVD~  
for(int i=0;i<nEndPos.length-1;i++) SH1S_EQ<  
{ MlKSjKl" !  
nEndPos = nStartPos[i+1]; VY#nSF`  
} -){aBMOv3  
nEndPos[nEndPos.length-1] = nFileLength; =&K8~   
} 1m~-q4D)V  
} TCWt3\  
wU}%]FqtZ=  
-I0J-~#  
//启动子线程 ;T\+TZtI  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ?-v]+<$Y  
for(int i=0;i<nStartPos.length;i++) N^Hj%5  
{ ljP<WD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `R!%k]$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), '< .gKo  
nStartPos,nEndPos,i); <9dfbI)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); H`bS::JI-  
fileSplitterFetch.start(); ?hmuAgOtbh  
} 4JO[yN  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Nsf>b8O  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); vojXo|c  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Ur9L8EdC  
nEndPos = " + nFileLength); B&+)s5hh  
// fileSplitterFetch[nPos.length-1].start(); YD{Ppz  
/lS5B6NU  
V(5*Dn84  
//等待子线程结束 mHyT1e  
//int count = 0; s-801JpiJ  
//是否结束while循环 po!bRk[4  
boolean breakWhile = false; Y@y"bjK \  
l`<1Y|  
koa-sy)#L  
while(!bStop) 8l l}"  
{ dQs>=(|t  
write_nPos(); WYN0,rv1:+  
Utility.sleep(500); eH ]9"^> o  
breakWhile = true; \0veld  
7G+E+A5o&  
Kw7uUJR  
for(int i=0;i<nStartPos.length;i++) -#Ys67,4N  
{ v[<x>?i D_  
if(!fileSplitterFetch.bDownOver) Q~f mVWq  
{ SE$~Wbj?  
breakWhile = false; M?_7*o]!  
break; m-2!r*(zt  
} o1Krp '*  
} 8#nAs\^  
if(breakWhile) TD sjNFe3  
break; K!,9qH  
5gSe=|we*p  
Jsa]RA  
//count++; ZmDM=qN  
//if(count>4) 7?;ZE:  
// siteStop(); c'INmc I|  
} tIT/HG_o  
Z*+y?5+L"P  
&`IJ55Z-)  
System.err.println("文件下载结束!"); &u!MI  
} rI OKCL?  
catch(Exception e){e.printStackTrace ();} SyI\ulmL  
} )UtK9;@"  
if?X^j0  
PA*1]i#2M=  
//获得文件长度 zZW5M^z8  
public long getFileSize() +|--}iE5n  
{ h0 Xc=nj  
int nFileLength = -1; =q(?ALGc  
try{ ,e^~(ITaq  
URL url = new URL(siteInfoBean.getSSiteURL()); 8,IQ6Or|-2  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )3WUyD*UZN  
httpConnection.setRequestProperty("User-Agent","NetFox"); R7 rO7M !  
6:q,JB@i  
vm7ag 7@O  
int responseCode=httpConnection.getResponseCode(); PXG@]$~3  
if(responseCode>=400) o!lKP>  
{ jwg*\HO,s  
processErrorCode(responseCode); h$#PboLd  
return -2; //-2 represent access is error K 6yD64  
} :NL[NbQYt  
*'*,mfk[  
<MKX F V  
String sHeader; !+z&] S3s  
HV'M31m~q  
e8E'X  
for(int i=1;;i++) }G "EdhSl  
{ v 8EI   
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1gnLKfc  
//Utility.log(in.readLine()); 1*e7NJ/.,  
sHeader=httpConnection.getHeaderFieldKey(i); 9^8_^F  
if(sHeader!=null) ->*~e~T  
{ kxR!hA8wv4  
if(sHeader.equals("Content-Length")) k8!:`jG  
{ *&tTiv{^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); N,Js8Z"  
break; lvRTy|%[  
} LM(r3sonb  
} (+6N)9rj`/  
else MJ$.ST  
break; jZQ{ XMF  
} :*/g~y(fE  
} /'zXb_R,$  
catch(IOException e){e.printStackTrace ();} oVr:ZwkG3  
catch(Exception e){e.printStackTrace ();} ^oYRB EIJH  
505ejO|  
@r^s70{}  
Utility.log(nFileLength); P @J)S ?  
Fn0 |v66  
Ct^=j@g  
return nFileLength; ,:#h;4!VRF  
} BnfuI  
/bn$@Cy@  
*8+HQ[[#  
//保存下载信息(文件指针位置) DZ1.Bm0  
private void write_nPos() *Z\AO'h=Z  
{ #?`S+YN!q)  
try{ u9(42jj[$U  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *7=`]w5k1  
output.writeInt(nStartPos.length); ~N/a\%`  
for(int i=0;i<nStartPos.length;i++) f~,Ml*Zp  
{ "Ec9.#U/  
// output.writeLong(nPos); #C'E'g0  
output.writeLong(fileSplitterFetch.nStartPos); EM@EB< pRX  
output.writeLong(fileSplitterFetch.nEndPos); h4=mGJpm  
} ;at1|E*  
output.close(); vRn]u57O  
} ^O =G%de  
catch(IOException e){e.printStackTrace ();} w ~"%&SNN  
catch(Exception e){e.printStackTrace ();} BR-wL3x b  
} X Ai0lN{,  
tSnsjd<6.  
$-|$4lrS  
//读取保存的下载信息(文件指针位置) }I MV@z B  
private void read_nPos() 9 ~$E+ m(  
{ a#G3dY>  
try{ _mk@1ft  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); f`*VNB`  
int nCount = input.readInt(); 4<vi@,s  
nStartPos = new long[nCount]; FhPCFmmUT  
nEndPos = new long[nCount]; @h_ bXo  
for(int i=0;i<nStartPos.length;i++) SkC.A ?  
{ Vugb;5Vl  
nStartPos = input.readLong(); D SWmQQ  
nEndPos = input.readLong(); kma>'P`G  
} fFoZ! H  
input.close(); C@[U:\  
} fP6.  
catch(IOException e){e.printStackTrace ();} ?RIf0;G  
catch(Exception e){e.printStackTrace ();} e2K9CE.O  
} KK5_;<  
00s)=A_  
xt IF)M  
private void processErrorCode(int nErrorCode) FzP1b_i  
{ -j2y#aP  
System.err.println("Error Code : " + nErrorCode); 6|{&7=1t  
} |:Maa6(W  
$TS97'$  
kj.9\  
//停止文件下载 pq\N 2d  
public void siteStop() D%LYQ  
{ wr=K AsH<  
bStop = true; BjsTHS&  
for(int i=0;i<nStartPos.length;i++) ,Vo[mB  
fileSplitterFetch.splitterStop(); I.(@#v7T  
r b\t0tg  
|Ldvfd  
} r{84Y!k~*  
} WRAL/  
//负责部分文件的抓取 1X`,7B@pz  
**FileSplitterFetch.java $o;c:Kh$$  
*/ g oyQ',+  
package NetFox; >dJ~  
(fr=N5   
_ h1eW9q  
import java.io.*; #`f{\  
import java.net.*; h^qZi@L  
:vx<m_  
Q$ Dx:  
public class FileSplitterFetch extends Thread { Z h9D^ I  
olA+B  
dFhyT.Y?  
String sURL; //File URL R".$x{{  
long nStartPos; //File Snippet Start Position -^(KGu&L&u  
long nEndPos; //File Snippet End Position =au!rda  
int nThreadID; //Thread's ID A+frKoi  
boolean bDownOver = false; //Downing is over HB$?}V  
boolean bStop = false; //Stop identical L<3+D  
FileAccessI fileAccessI = null; //File Access interface rnQ_0d  
a j$& 9][  
dKC*QHU  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException NP.i,H  
{ 6 >;OVX  
this.sURL = sURL; : ir3u  
this.nStartPos = nStart; *)`PY4zF  
this.nEndPos = nEnd; &WL::gy_S  
nThreadID = id; e57R6g)4  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 :dRC$?f4  
} 9wGsHf8]  
+]( y  
)bL(\~0g~  
public void run() aPK:k$.  
{ >;Vfs{Z(q  
while(nStartPos < nEndPos && !bStop) Njr;Wa.r+  
{ Zlh 2qq  
,Wu$@jD/ ]  
Skr0WQ  
try{ {X{S[(|  
URL url = new URL(sURL); s^IC]sW\%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); x3#:C=  
httpConnection.setRequestProperty("User-Agent","NetFox"); c2,g %(  
String sProperty = "bytes="+nStartPos+"-"; }o7-3!{L!  
httpConnection.setRequestProperty("RANGE",sProperty); j[FB*L1!D  
Utility.log(sProperty); rPyjr(I"_  
"\`Fu  
1cMLl6Bp>  
InputStream input = httpConnection.getInputStream(); ai1;v@1  
//logResponseHead(httpConnection); 1%R${Qhr  
M*D_p n&  
%t!r pyD  
byte[] b = new byte[1024]; |4P8N{ L>O  
int nRead; 9&Un|cr  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /wJ4hHY  
{ $gz8! f?  
nStartPos += fileAccessI.write(b,0,nRead); GD d'{qE6  
//if(nThreadID == 1) L kl E,W  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z;2& d<h  
} vO&X<5?Qc  
+J;b3UE#  
3`vKEThY)  
Utility.log("Thread " + nThreadID + " is over!"); T,uF^%$@AQ  
bDownOver = true; $joGda  
//nPos = fileAccessI.write (b,0,nRead); ]3,  
} -!qjBK,`X  
catch(Exception e){e.printStackTrace ();} u9~Ncz  
} F%&lM[N%  
} @NL<v-t  
<T)0I1S  
`v)'(R7){  
//打印回应的头信息 &v1E)/q{Z  
public void logResponseHead(HttpURLConnection con) DbB<8$  
{ HWB\}jcA6u  
for(int i=1;;i++) 59SL mj  
{ N%Y!{k5T7  
String header=con.getHeaderFieldKey(i); !\d~9H%`B  
if(header!=null) ,30lu a  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); :E|Jqi\  
Utility.log(header+" : "+con.getHeaderField(header)); islHtX VE  
else >R6mI  
break; O;V^Fk(  
} tWzBQx   
} 2Og5e  
ml^=y~J[  
$M0l (htR  
public void splitterStop() \?Z7|   
{ QJVB:>A  
bStop = true; v?6*n >R  
} GYb&'#F~t  
dqQJC qc!  
N#RC;  
} XRQ1Uh6  
G4'Ee5(o  
_%Xp2`m  
/* 8rlf9m  
**FileAccess.java DCLu^:|C"  
*//文件访问(定位,写) <8? F\x@  
package NetFox; jVOq/o  
import java.io.*; L>g6 9D !  
)CE]s)6+2  
J1cz D|(  
public class FileAccessI implements Serializable{ FW;}S9u3  
:eD-'#@$u  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 L >"O[@  
RandomAccessFile oSavedFile; ??P\v0E  
long nPos; sKKc_H3YSH  
3WwCo.q;m  
tq~f9EvC  
public FileAccessI() throws IOException yX{7<\x   
{ M[O22wFs  
this("",0); g{sp<w0  
} ,?qJAV~>  
l qh:c  
'-n Iy$>  
public FileAccessI(String sName,long nPos) throws IOException AX6:*aZB  
{ <3N\OV2  
oSavedFile = new RandomAccessFile(sName,"rw"); ''q;yKpaz  
this.nPos = nPos; e:4,rfF1  
oSavedFile.seek(nPos); *\}$,/m['  
} ht6}v<x.eA  
/g9^g(  
FYE(lEjxi  
public synchronized int write(byte[] b,int nStart,int nLen) _99 +Vjy  
{ t.RDS2N|  
int n = -1; aQY.96yo  
try{ }QQl.'  
oSavedFile.write(b,nStart,nLen); *sB'D+-/  
n = nLen; dxZn| Y  
} Gl3g.`X{$@  
catch(IOException e) (vi^ t{k  
{ L[Y$ `e{zd  
e.printStackTrace (); .=G3wox3  
} Qh Rj*,  
+8 \?7,FY  
%" mki>  
return n; + `'wY?  
} | a i#rU  
}uaFmXy3  
=s'H o  
} 3xP<J)S0  
?y>v"1+  
wouk~>Jft  
/* =u0a/2u|  
**SiteInfoBean.java !H c6$  
*/ ~p{YuW[e  
package NetFox; ?/hS1yD;  
uX{g4#eG  
>,k2|m  
public class SiteInfoBean { *>W6,F7  
F2Ny=H &G  
[4B (rra  
private String sSiteURL; //Site's URL |d6/gSiF  
private String sFilePath; //Saved File's Path 1g,gilc  
private String sFileName; //Saved File's Name !{(crfXB  
private int nSplitter; //Count of Splited Downloading File +gBD E :  
a5pM~.]  
o@j!JI&  
public SiteInfoBean() F &5iA\  
{//nSplitter的缺省值为5 Wie0r@5E  
//default value of nSplitter is 5 QJR},nZ3  
this("","","",5); J &=5h.G$  
} /J!hKK^k  
F`,bFQ  
<.BY=z=H  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) HJ"sK5Q  
{ "iK'O =M  
sSiteURL= sURL; 0N4ZV}s,d  
sFilePath = sPath; >k=@YLj  
sFileName = sName; lY,9bSF$  
this.nSplitter = nSpiltter; :AuKQ`c  
OzRo  
|@R/JGB^  
} Ly v"2P  
G$Fo*;Fl  
TOSk+2P  
public String getSSiteURL() l_+q a6C*  
{ -H_#et3&i  
return sSiteURL; I7'v;*  
} &js$qgY  
AtAu$"ue  
_XrlCLp: d  
public void setSSiteURL(String value) l#>A.-R*`  
{ !>K=@9NC|.  
sSiteURL = value; YxU->Wi]G  
} NP~3!b  
J]48th0,  
9 v ,y  
public String getSFilePath() D`B*+  
{ SwrzW'%A  
return sFilePath; k4:=y9`R}$  
} s6 K~I  
-I#<?=0B  
MfFmJ7>Bg  
public void setSFilePath(String value) gMZrtK`<  
{ 76c:* bZ  
sFilePath = value; S!JLy&@  
} %/s+-j@s:  
H6 $pA^  
6Ol)SQE,  
public String getSFileName() ~1,$  
{ w/(2fU(  
return sFileName; />PH{ l  
} ({C|(v9 C7  
O4a~(*f  
YsTF10  
public void setSFileName(String value) su8()]|0x  
{ d,j)JnY3V  
sFileName = value; O#vIn}  
} $V_w4!:Q  
\C1`F [d_  
&&96kg3  
public int getNSplitter() |hu9)0 P  
{ r6 pz(rCs}  
return nSplitter; nK]L0*s  
} "!Hm.^1  
ET6}V"UD  
cI <T/~P  
public void setNSplitter(int nCount) c&SSf_0O*  
{ :pP l|"  
nSplitter = nCount; GN|xd+O_  
} 7V~ gqum  
} s8r[U, }(  
]XfROhgP=  
79'N/:.  
/* yfA h=  
**Utility.java 8&#)}A}x  
*/ h~&5;  
package NetFox; >T29kgF2  
%b ^.Gw\L  
$*+UX   
public class Utility { ;@[ax{ J  
BUla2p  
D CSTp2  
public Utility() Iw</X}#\  
{ t@BhosR-  
m&6)Vt  
U {s T %G  
} Aq&H-g]s  
MrS~u  
//线程睡眠 6 &MATMR  
public static void sleep(int nSecond) mH4Jl1S&  
{ t hQ)J|1  
try{ j"P}Wn  
Thread.sleep(nSecond); p=f8A71  
} "nn>I}jK  
catch(Exception e) ]y/!GFQ  
{ tWI4x3 &2  
e.printStackTrace (); 3Ett9fBd  
} "3uPK$  
} 1Qo2Z;h@  
d@<~u,Mt&F  
//日志 !}&f2!?.W  
public static void log(String sMsg) inv 5>OeG  
{ xz vbjS W  
System.err.println(sMsg); tc)4$"9)  
} dWDf(SS  
7@9R^,M4:  
!XrnD#  
public static void log(int sMsg) DzK%$#{<  
{ >^+c s^jCM  
System.err.println(sMsg); 7T9Mo .  
} :|E-Dx4F6H  
} (n~GKcA  
#p|7\Y  
PQ`~qM:3st  
/* v.e~m2u_F  
**TestMethod.java 8j&LU,  
*/ ZNTOI]P&  
package NetFox; ADVHi3b  
TmO3hKaP  
R"k}wRnxY  
public class TestMethod { ]tDuCZA  
*lws7R  
V|zatMHs  
public TestMethod() lG!We'?  
{ ///xx/weblogic60b2_win.exe LuUfdzH  
try{ zD}2Zh]  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *Z=:?4u  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); IAa}F!6Q1  
SiteFileFetch fileFetch = new SiteFileFetch(bean); zXx)xIO  
fileFetch.start(); j69 2M.A  
} |dQ-l !  
catch(Exception e){e.printStackTrace ();} x5)YZ~5  
)M(-EDL>Qk  
B&k"B?9mL  
} j @+QwZL|  
BD (  
C@Fk  
public static void main(String[] args) Y)]x1I  
{ ley: =(  
new TestMethod(); CHX- 4-84{  
} v08Xe*gNU  
} )=c/{  
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