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http断点续传简单实现(java)

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/* x4H#8ZK!  
**SiteFileFetch.java p?rlx#M  
*/ cj8cV|8@  
package NetFox; EX`P(=zD  
import java.io.*; EbQLMLD%  
import java.net.*; `S@TiD*  
lZ\8W^  
S13cQ?4  
public class SiteFileFetch extends Thread { GrL{q;IO  
'kZ,:.v  
xLz=)k[''  
SiteInfoBean siteInfoBean = null; //文件信息Bean -[V-f> :  
long[] nStartPos; //开始位置 GlAI~\A  
long[] nEndPos; //结束位置 p?:5 U[KM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1q;v|F  
long nFileLength; //文件长度 Nujnm$!,Q  
boolean bFirst = true; //是否第一次取文件 =#b@7Yw:  
boolean bStop = false; //停止标志 WKEb '^  
File tmpFile; //文件下载的临时信息 dq[h:kYm  
DataOutputStream output; //输出到文件的输出流 \beO5]KS<  
C8}:z\A_@Z  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) }9'`3vsJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException :jLL IqhB  
{ L8QWEFB|  
siteInfoBean = bean; .gRj^pu   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); B )r-,M  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); A IP~A]T  
if(tmpFile.exists ()) az(<<2=  
{ PLyity-L[7  
bFirst = false; Cl}nP UoL  
read_nPos(); Nz,yd%ua  
} 9B: 3Ha=  
else DZ8|20b  
{ i<m(neX[H  
nStartPos = new long[bean.getNSplitter()]; Pd*[i7zhC  
nEndPos = new long[bean.getNSplitter()]; I0)`tQ +  
} rVYoxXv  
>1~ /:DJ  
<$(B[T  
^/2I)y]W0  
} /8cRPB.  
0M_oFx  
x<NPp&GE  
public void run() C9 n%!()>  
{ .V?:&_}_I6  
//获得文件长度 W(s4R,j  
//分割文件 |^pev2g  
//实例FileSplitterFetch 9E!le=>  
//启动FileSplitterFetch线程 NK_|h %  
//等待子线程返回 {m.$EoS  
try{ p T(M>LP83  
if(bFirst) Ux [<g%F"  
{ /U~|B.z@6  
nFileLength = getFileSize(); \*xB<mq  
if(nFileLength == -1) /d8o*m'bu!  
{ X*8y"~X|vq  
System.err.println("File Length is not known!"); *v>ZE6CL  
} )h!cOEt  
else if(nFileLength == -2) A=Wg0eYy\  
{ &],uD3:5O  
System.err.println("File is not access!"); =!O->C:  
} #o.e (C  
else q+ $6D;9  
{ Sqo+cZ  
for(int i=0;i<nStartPos.length;i++) Jg6Lr~!i  
{ `2s!%/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); +K57. n{  
} ^mS |ff  
for(int i=0;i<nEndPos.length-1;i++) a|aVc'j  
{ bLgH3[{  
nEndPos = nStartPos[i+1]; /:&!o2&1H  
} Lsmcj{1d  
nEndPos[nEndPos.length-1] = nFileLength; ^PksXfk  
} J3K=z  
} RgE`Hr  
"/#JC} ]  
tT$OnZu&  
//启动子线程 *sho/[~_  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^URCnJ67Se  
for(int i=0;i<nStartPos.length;i++) mP(3[a_Q  
{ (C2 XFg_  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Nk`UQ~g$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), o\AnM5  
nStartPos,nEndPos,i); 5gszAvOO  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v<qh;2  
fileSplitterFetch.start(); z*y!Ml1  
} `&$8/_`  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), JE?p'77C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); V|7YRa@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", L+%"e w  
nEndPos = " + nFileLength); ) nfoDG#O  
// fileSplitterFetch[nPos.length-1].start(); =P- &dN  
`+J Fvn!  
P:qmg"i@3  
//等待子线程结束 !*IMWm>  
//int count = 0; T5BZD +Ta  
//是否结束while循环 G7-BeA8  
boolean breakWhile = false; wucdXj{%  
l.[pnLD  
CI|lJ  
while(!bStop) +Q*`kg'  
{ !,WGd|oJ  
write_nPos(); XX;4A  
Utility.sleep(500); 30Yis_l2h  
breakWhile = true; bdUPo+  
g8),$:Uw  
)^h6'h`  
for(int i=0;i<nStartPos.length;i++) bQll;U^A  
{ ?Cq7_rq  
if(!fileSplitterFetch.bDownOver) cw;wv+|k  
{ ZO}Og&%  
breakWhile = false; #m+!<  
break; l?Y^3x}j  
} `sxfj)s  
} 0bNvmZ$  
if(breakWhile) bm588UQ  
break; +Qs]8*^?;  
k_=SDm a  
NzRvbj]  
//count++; jXcJ/g(X3  
//if(count>4) OI R5QH  
// siteStop(); ]n ?x tI  
} FoefBo?g65  
HDyf]2N*N  
-DDA b(2*  
System.err.println("文件下载结束!"); xVvUx,t  
} 'X~tt#T  
catch(Exception e){e.printStackTrace ();} fSh5u/F!  
} T?9D?u?]  
*P()&}JK  
<J[ le=  
//获得文件长度 ? @V R%z  
public long getFileSize() B( [x8A]  
{ eh# 37*-  
int nFileLength = -1; yIw}n67  
try{ @WJ;T= L  
URL url = new URL(siteInfoBean.getSSiteURL()); oL4W>b )  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); We+rFk1ddt  
httpConnection.setRequestProperty("User-Agent","NetFox"); |J`EM7qMK  
TyxIlI4"  
VFT@Ic#]  
int responseCode=httpConnection.getResponseCode(); ?-??>& z  
if(responseCode>=400) iP/v "g"g  
{ U%{GLO   
processErrorCode(responseCode); G#iQX`  
return -2; //-2 represent access is error A#u U ]S  
} WlL(NrVA@@  
2FcL-?  
4Nm>5*]  
String sHeader; }E`Y.= S  
3f|}p{3  
b`0tfXzS5  
for(int i=1;;i++) L aTcBcI  
{ B|(g?  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -K"'F`;W  
//Utility.log(in.readLine()); sW^M  ]  
sHeader=httpConnection.getHeaderFieldKey(i); &K[*vyD  
if(sHeader!=null) pjl%Jm  
{ 4Z)4WGp!  
if(sHeader.equals("Content-Length")) P -m_],  
{ dQut8>0&  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); '1<Z"InU  
break; {N(qS'N  
} +vc+9E.?9  
} 570Xk\R@M  
else DF%d/a{]  
break; 3)OZf{D[  
} `CK~x =  
} uf(ayDE  
catch(IOException e){e.printStackTrace ();} :XKYfc_y  
catch(Exception e){e.printStackTrace ();} ~G@NWF?7  
[%IOB/{N  
Ht`fC|E  
Utility.log(nFileLength); /iW+<@Mas  
]kh]l8t^  
l![M,8  
return nFileLength; ~NGM6+9  
} e8a^"Z`a  
6(|mdk`i  
p l)":}/)  
//保存下载信息(文件指针位置) 1- RY5R}VR  
private void write_nPos() za l]t$z>  
{ IrwQ~z3I  
try{ #-az]s|N  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ^[ae )}  
output.writeInt(nStartPos.length); {9IRW\kn  
for(int i=0;i<nStartPos.length;i++) .X g.,kW  
{ >OG189O  
// output.writeLong(nPos); w7)pBsI  
output.writeLong(fileSplitterFetch.nStartPos); ~Ps*i]n(  
output.writeLong(fileSplitterFetch.nEndPos); zI88IM7/  
} !E7gI qo  
output.close(); KbJ6U75|f  
} ^0,}y]5p  
catch(IOException e){e.printStackTrace ();} aRd~T6I  
catch(Exception e){e.printStackTrace ();} o'Bd. B  
} 6:1`lsP  
,%i Scr,z  
T2{e 1 =Z7  
//读取保存的下载信息(文件指针位置) h y rPu_  
private void read_nPos() 0 _!0\d#c  
{ 7KtU\u  
try{ M-WSdG[AJ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ulR yt^bx|  
int nCount = input.readInt(); SH*'<  
nStartPos = new long[nCount]; ^Z (cV g  
nEndPos = new long[nCount]; /E>;O47a  
for(int i=0;i<nStartPos.length;i++) ;_sJ>.=\  
{ ;H$ Cq' I  
nStartPos = input.readLong();  D2e-b  
nEndPos = input.readLong(); yoE-a  
} goM;Pf "<  
input.close(); z:'m50'  
} D@=]mh6vl  
catch(IOException e){e.printStackTrace ();} ~tUZQ5"  
catch(Exception e){e.printStackTrace ();} L K&c~ Uy  
} j/v>,MM  
3 9 8)\3o  
UrniJB]  
private void processErrorCode(int nErrorCode) :kZ]Swi 5  
{ g%2G=gR$?z  
System.err.println("Error Code : " + nErrorCode); 'afW'w@  
} 2 BY|Cp4R  
b"g^Jm! j  
G<Z}G8FW^  
//停止文件下载 3Vu}D(PJ  
public void siteStop() ];.5 *a%*  
{ D5zc{) /  
bStop = true; ] 0i[=  
for(int i=0;i<nStartPos.length;i++) L03I:IJ  
fileSplitterFetch.splitterStop(); %<i sdvF  
b:1B >  
5nPvEN/  
} O:]']' /  
} 1N/4W6  
//负责部分文件的抓取 ? Fqh i  
**FileSplitterFetch.java /%YW[oY{V  
*/ f,YORJ  
package NetFox; v]JET9hY  
<5Vf3KoC&  
A-x^JC=  
import java.io.*; 81RuNs]  
import java.net.*; mF gqM:  
dJ"44Wu+J  
,7nu;fOT[  
public class FileSplitterFetch extends Thread { g}9 ,U&$]y  
6O4 *OR<&  
iBE|6+g~Cj  
String sURL; //File URL a$W O} g?  
long nStartPos; //File Snippet Start Position AFt- V  
long nEndPos; //File Snippet End Position V``|<`!gd  
int nThreadID; //Thread's ID R6~6b&-8  
boolean bDownOver = false; //Downing is over PpRS4*nR  
boolean bStop = false; //Stop identical G>~/  
FileAccessI fileAccessI = null; //File Access interface 1I;q@g0  
74_?@Z(  
s$y_(oU,D  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException '{`KYKLP+  
{ 4'faE="1)S  
this.sURL = sURL; Fd8nR9A  
this.nStartPos = nStart; d /jx8(0  
this.nEndPos = nEnd; 33` bKKO}  
nThreadID = id; P IG,a~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 U=v>gNba  
} -O} )Y>=}  
$GoS?\G  
 v9T 3=  
public void run()  hyxv+m[  
{ x ]VycS  
while(nStartPos < nEndPos && !bStop) #kQ! GMZH  
{ CI+)0=`<1B  
HOD?i_  
.J.}}"+U  
try{ W *0!Z:?  
URL url = new URL(sURL); ( w4XqVT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); <v ub Q4  
httpConnection.setRequestProperty("User-Agent","NetFox"); sta/i?n  
String sProperty = "bytes="+nStartPos+"-"; J5b3r1~D"[  
httpConnection.setRequestProperty("RANGE",sProperty); 6I[*p0j5  
Utility.log(sProperty); J rK{MhO  
7$7|~k  
s?<FS@k  
InputStream input = httpConnection.getInputStream(); :] Wn26z)  
//logResponseHead(httpConnection); d{TcjZ  
H:b"Vd"x9  
}51QUFhL0  
byte[] b = new byte[1024]; A._CCou  
int nRead; QeY+imM  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [,&g46x22  
{ [\F:NLjiUy  
nStartPos += fileAccessI.write(b,0,nRead); DN9x<%/-  
//if(nThreadID == 1) M5[#YG'FlQ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^PdD-tY<  
} i~GW  
T7YJC,^m  
:Gz$(!j1.'  
Utility.log("Thread " + nThreadID + " is over!"); h-.^*=]R6  
bDownOver = true; uA`e  
//nPos = fileAccessI.write (b,0,nRead); lBn<\Y!^  
} W)`>'X`  
catch(Exception e){e.printStackTrace ();} OL=X&Vaf<  
} ;8VZsh  
} `?:{aOI  
[/ CB1//Y  
!d0$cF):  
//打印回应的头信息 ~#EXb?#uS  
public void logResponseHead(HttpURLConnection con) gISA13  
{ Pf8_6z_  
for(int i=1;;i++) [:,|g;=Y}  
{ ~+6#4<M.~  
String header=con.getHeaderFieldKey(i); C&q}&=3r  
if(header!=null) R||$Wi[$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [L7S`Z  
Utility.log(header+" : "+con.getHeaderField(header)); Ev#, }l+  
else W9Us I  
break; bil>;&h  
} 7ey|~u2  
} yyPj!<.MGP  
ILNghtm-  
+vFqHfmP  
public void splitterStop() -vT$UP  
{ E=v4|/['N  
bStop = true; ABE EJQ  
} 4&]NC2I  
GNG.N)q#C  
: Q,O:  
} Z(E .F,k  
bz&9]% S<  
,0L< wa  
/* 11$v~<M  
**FileAccess.java 84(jg P  
*//文件访问(定位,写) Q1h v2*/U  
package NetFox; N9c#N%cu  
import java.io.*; T~>&m~} +  
U:/_T>f%  
NFU=PS$  
public class FileAccessI implements Serializable{ cP21x<n  
TDtHR hq7  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 EY1L5 Ba.  
RandomAccessFile oSavedFile; LGy!{c  
long nPos; Yv*i69"  
"| oW6@  
4[0.M  
public FileAccessI() throws IOException +'e3YF+'  
{ a(U/70j  
this("",0); /[3!kW  
} QK~>KgVi  
I#yd/d5^  
wS2N,X/Y  
public FileAccessI(String sName,long nPos) throws IOException u<@ 55k  
{ V6<Ki  
oSavedFile = new RandomAccessFile(sName,"rw"); !OH'pC5  
this.nPos = nPos; BD ,3JDqT  
oSavedFile.seek(nPos); 51%<N\>/4  
} D@mqfi(x  
t/"9LMKs?  
ht)KS9Xu  
public synchronized int write(byte[] b,int nStart,int nLen) WtSlD9 h  
{ [yAR%]i-7  
int n = -1; {XS2<!D  
try{ &kOb#\11u  
oSavedFile.write(b,nStart,nLen); avv/mEf-f  
n = nLen; /3vj`#jD  
} 4p&SlJ  
catch(IOException e) nYY'hjZ  
{ MU_ >+Wnf  
e.printStackTrace (); b~G|Bhxa  
} RK]."m0c~#  
'$OLU[(Y  
TLzcQ|  
return n; m+'X8}GC#O  
} XG6UV('  
PDh1*bf{u  
wa9{Q}wSa  
} ;/nR[sibN  
X?"Ro`S  
pQxi0/dp  
/* X/wqfP  
**SiteInfoBean.java }Sb&ux  
*/ K[|d7e  
package NetFox; v3jx2Z  
UUql"$q  
F9SIC7}uH  
public class SiteInfoBean { j#XU\G  
(aH_K07  
7<ES&ls_  
private String sSiteURL; //Site's URL q} R"  
private String sFilePath; //Saved File's Path |7T!rnr  
private String sFileName; //Saved File's Name /9yA.W;  
private int nSplitter; //Count of Splited Downloading File ;c>Rjg&[  
'uOp?g'7  
Ie;}k;?-  
public SiteInfoBean() seH#v  
{//nSplitter的缺省值为5 :!EOg4%i  
//default value of nSplitter is 5 WxLILh  
this("","","",5); 4B8{\ "6  
} pRdO4?l  
&"svt2  
h:+>=~\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ZjJEjw  
{ WS0RvBvb  
sSiteURL= sURL; Wm ?RB0  
sFilePath = sPath; BPKeG0F7  
sFileName = sName; U `"nX)$  
this.nSplitter = nSpiltter; Ih95&HsdC  
c~Hq.K$d  
LNU9M>  
} BT+ws@|[  
h^0!I TL^  
0)qLW& w  
public String getSSiteURL() vi>V6IC4v  
{ >!YI7)  
return sSiteURL; #6JCm!s  
} 7QRtNYo#\  
{ByT,92  
VL<)d-  
public void setSSiteURL(String value) IV:Knh+ ?  
{ ji2if.t@  
sSiteURL = value; G>{;@u  
} FyQ^@@  
)P.|Xk:r  
B|~\m ~  
public String getSFilePath() D`.CXFI+U  
{ NLF{W|X  
return sFilePath; |^@TA=_  
} o0Hh&:6!M  
L+QEFQ:r5  
Da8qR+*x  
public void setSFilePath(String value) )5X7|*LP  
{ ?z60b=f8  
sFilePath = value; ^IM;D)X&:  
} I#f<YbzD  
\Jv6Igu  
PHD$E s  
public String getSFileName() 4oOe  
{ _Oq (&I  
return sFileName; s\Cl3  
} Ph.$]yQCc]  
/^0Hi4+\  
J]|-.Wv1  
public void setSFileName(String value) ?(U> )SvF  
{ U1rh[A>  
sFileName = value; Y6fU;  
} JX/rAnc@  
!H,R$3~  
e$tKKcj0T  
public int getNSplitter() D x Vt  
{ ;LH?Qu;e  
return nSplitter; 4F 8`5)RM  
}  c:~o e  
\aT._'=M+  
<H E'5b  
public void setNSplitter(int nCount) Jo h&Ay  
{ K#";!  
nSplitter = nCount; 4k$BqM1  
} JUU0Tx:`9)  
} )CXJRo`j0  
$K8ZxH1z@  
OH*[  
/* m.EWYO0XQ  
**Utility.java m(Bv}9  
*/ +V7*vlx-  
package NetFox; 5'>(|7~%\  
Q:kpaMA1P  
g >-iBxml  
public class Utility { .f&,~$e4  
I[<C)IG  
35jP</  
public Utility() sOLo[5y'  
{ F/RV{} 17E  
_.FxqH>  
qdj,Qz9ly  
} K$' J:{yY  
tp*AA@~  
//线程睡眠 <h7C_^L10\  
public static void sleep(int nSecond) l= !KZaH  
{ vM\8>p*U  
try{  HPwmi[  
Thread.sleep(nSecond); 8u;l<^<  
} rmR7^Ycv/  
catch(Exception e) a50{gb#  
{ =`vUWONn  
e.printStackTrace (); &sWq SS  
} U#,2et6  
} ;U}lh~e11  
31YzTbl[H  
//日志 )Cyrs~  
public static void log(String sMsg) }QG6KJh_%  
{ HHoh//(\  
System.err.println(sMsg); T92k"fBY  
} ZZFa<AK4  
0V`0="rQ  
|3\ mH~Bw  
public static void log(int sMsg) {b+!0[  
{ ](- :l6  
System.err.println(sMsg); tX Z5oG7  
} +~02j1Jx  
} K}! VY`  
ep,kImT  
~++y4NB8Q  
/* ~XQN4Tv-  
**TestMethod.java a{69JY5  
*/ (? YTQ8QR  
package NetFox; i+T$&$b  
Al' sY^B  
Kv!CL9^LX7  
public class TestMethod { )MW.Y  
oXV  
~n|*-rca  
public TestMethod() eH=lX9  
{ ///xx/weblogic60b2_win.exe 3MiNJi#=2  
try{ f#/v^Ql*  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); +vBq,'k`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); m/%sBw\rx  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 07# ~cVI  
fileFetch.start(); !1)lGjMW  
} Sep}{`u  
catch(Exception e){e.printStackTrace ();} ;wgm 'jr  
N~g'Z `  
4wMKl6mL  
} # TC x8]F  
nXk<DlTws  
VL&E2^*E  
public static void main(String[] args) L5of(gQ5]  
{ >Ex\j?  
new TestMethod();  N6E H  
} q%"]}@a0  
} hf8 =r5j=  
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