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http断点续传简单实现(java)

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/* ccY! OSae  
**SiteFileFetch.java JC.nfxG@:  
*/ 61~7 L^882  
package NetFox; Js'j}w  
import java.io.*; U~GQ JR  
import java.net.*; =v{Vl5&>?  
'Z8=y[l  
["1Iz{  
public class SiteFileFetch extends Thread { vACJE  
f 0r?cZ  
sKwUY{u\M  
SiteInfoBean siteInfoBean = null; //文件信息Bean G@+R!IG  
long[] nStartPos; //开始位置 l{mC|8X  
long[] nEndPos; //结束位置 XM57 UG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 XI\P#"  
long nFileLength; //文件长度 z(n Ba]^[F  
boolean bFirst = true; //是否第一次取文件 VCX^D)[-  
boolean bStop = false; //停止标志 4q)+nh~s  
File tmpFile; //文件下载的临时信息 2_Gb K-  
DataOutputStream output; //输出到文件的输出流 6 hiWgbE  
)?;+<,  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) #Dp]S, e  
public SiteFileFetch(SiteInfoBean bean) throws IOException vMzBp#MT  
{ K/0Wp %  
siteInfoBean = bean; s8  5l  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Nj{;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Ez / W$U  
if(tmpFile.exists ()) aen0XiB6~^  
{ Vt(s4  
bFirst = false;  a"D'QqtH  
read_nPos(); U&W/Nj  
} 'Pe;Tp>`  
else L:\>)6]Ls  
{ LT#EYnG  
nStartPos = new long[bean.getNSplitter()]; TPn#cIPG  
nEndPos = new long[bean.getNSplitter()]; 0"{-<Wot}  
} Z~] G+(  
|RL\2j|  
gh `]OxA  
!j/54,  
} i`5Skr:M  
P)O:lYX  
:{9HsF"h0  
public void run() u6Yp ,!+  
{ T037|k a{  
//获得文件长度 m=25HH7enb  
//分割文件 jLn|zK  
//实例FileSplitterFetch (aLjW=  
//启动FileSplitterFetch线程 3oV2Ek<d  
//等待子线程返回 7Vu f4Z5  
try{ f!F5d1N  
if(bFirst) KQ^|prN?y  
{ 29zMs9oKPP  
nFileLength = getFileSize(); Sx1|Oq]  
if(nFileLength == -1) <cxe   
{ /VD[:sU7  
System.err.println("File Length is not known!"); %2\6.c=c  
} V -_MwII-  
else if(nFileLength == -2) Uy|Tu~  
{ R'pfA B|!  
System.err.println("File is not access!"); `A#0If  
} `I8ep=VZ  
else k2(k0HFR  
{ 3WpQzuHPT  
for(int i=0;i<nStartPos.length;i++) 4X!4S6JfB  
{ RL[F 9g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); |;\pAZ2  
} i-9W8A  
for(int i=0;i<nEndPos.length-1;i++) ZYt1V"2VJ  
{ R@#xPv4o%  
nEndPos = nStartPos[i+1]; bVzJOBe  
} Q.fUpa v  
nEndPos[nEndPos.length-1] = nFileLength; T-h[$fxR_  
} N)PkE>%X  
} H^dw=kS  
]L2b|a3  
b7'l3mQjk  
//启动子线程 eJ6 #x$I,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9Vl}f^Gn  
for(int i=0;i<nStartPos.length;i++) L9oLdWa(C  
{ #=)!\   
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `q`ah_  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), GQjwr(  
nStartPos,nEndPos,i); <oi'yr  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); AxeQv'e  
fileSplitterFetch.start(); eSHsE 3}h  
} M!i*DU+SE  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), =oM#]M'G+(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ox_DEg7l  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", e1y#p3 @d  
nEndPos = " + nFileLength); zeq")A  
// fileSplitterFetch[nPos.length-1].start(); =k,?+h~  
`$XB_ o%@  
hk$I-  
//等待子线程结束 YQyI{  
//int count = 0; _s<s14+od  
//是否结束while循环 ^I yYck'y+  
boolean breakWhile = false; lr[T+nQ  
vz|(KN[  
-ssmj8:Q\|  
while(!bStop) R NQq"c\  
{ vexF|'!}0#  
write_nPos(); ?|pP&8r  
Utility.sleep(500); ]*gf$D  
breakWhile = true; @!j6y (@  
on"ENT  
]Yf^O @<<>  
for(int i=0;i<nStartPos.length;i++) gK(G1  
{ }p-/R'  
if(!fileSplitterFetch.bDownOver) t: oQHhO?  
{ rqnxRq  
breakWhile = false; +0j{$MPZ  
break; j8 `7)^  
} pQ!lY  
} &}0QnO_mj  
if(breakWhile) A:D9qp  
break; x%9Ca)r?}  
@'5*jXd  
*4LRdLMn  
//count++; mXS"nd30bD  
//if(count>4) XA(.O|VZ  
// siteStop(); |z"$^|@d?  
} "FhC"}N  
HG< z,gE 2  
<L11s%5-  
System.err.println("文件下载结束!"); :475FPy]  
} {0n p  
catch(Exception e){e.printStackTrace ();} $}0!dR2  
} e@;'#t  
BlZB8KI~  
AWPgrv/  
//获得文件长度 ){z#Y#]dP  
public long getFileSize() if*~cPnN  
{ 9;uH}j8sE  
int nFileLength = -1; N$v_z>6Z  
try{ ssS"X@VZ \  
URL url = new URL(siteInfoBean.getSSiteURL()); Mk=*2=d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'Z=_zG/RX  
httpConnection.setRequestProperty("User-Agent","NetFox"); H=*0KX{  
5''k|B>  
`HnZ{PKf  
int responseCode=httpConnection.getResponseCode(); 7cWeB5 e?O  
if(responseCode>=400) :?LNP3}  
{ 6rWq hIaI  
processErrorCode(responseCode); zDEgC  
return -2; //-2 represent access is error xLLTp7b(  
} PC+Soh*  
ki}Li*)7  
.w _BA)  
String sHeader; _(~LXk^C  
64 'QTF{D  
#@5VT* /7  
for(int i=1;;i++) 9z{g3m70@  
{ S.`hl/  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); b/JjA  
//Utility.log(in.readLine()); o0F,!}  
sHeader=httpConnection.getHeaderFieldKey(i); i%F2^R@!q/  
if(sHeader!=null) ZR0 OqSp]  
{ =./PY10'  
if(sHeader.equals("Content-Length")) 2~7*jA+Ab  
{ F|/6;&*?M  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); k h*WpX  
break; {oF;ZM'r  
} ]q4LN o  
} s]`6u yW"  
else AZ^>osr  
break; !FyO5`v  
} :?= 1aiS  
} Z%LS{o~LK.  
catch(IOException e){e.printStackTrace ();} u rQvJ  
catch(Exception e){e.printStackTrace ();} E BoC,{R#  
jk_yrbLc  
WBJn1  
Utility.log(nFileLength); uPN^o.,/.  
^jdtp  
ZAeJTCCk  
return nFileLength; |; mET  
} 3D5adI<aq"  
L0H^S)g  
#lSGH 5Fp?  
//保存下载信息(文件指针位置) }?Pa(0=U  
private void write_nPos() "}%j'  
{ /NR*<,c%  
try{ p[%~d$JUq  
output = new DataOutputStream(new FileOutputStream(tmpFile)); a #s Nd  
output.writeInt(nStartPos.length); V4CA*FEA  
for(int i=0;i<nStartPos.length;i++)  xiQc\k$  
{ vl}}h%BC  
// output.writeLong(nPos); yLnTIE3)  
output.writeLong(fileSplitterFetch.nStartPos); tQyQ+1  
output.writeLong(fileSplitterFetch.nEndPos); S:xs[b.ZZ  
} J|o<;9dg1  
output.close(); Sx Bo%  
} }TuMMO4+  
catch(IOException e){e.printStackTrace ();} f*hnzj  
catch(Exception e){e.printStackTrace ();} ?}W#j  
} A,4} $-7  
Bd;EI)JT  
[xGL0Z%)t  
//读取保存的下载信息(文件指针位置) 'cIFbjJ  
private void read_nPos() qT4`3nH:  
{ N>P" $  
try{ FOPmvlA\-<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Oq3t-omXS  
int nCount = input.readInt(); 8(A k  
nStartPos = new long[nCount]; }095U(@  
nEndPos = new long[nCount]; |\"%Dy[m  
for(int i=0;i<nStartPos.length;i++) :'fK`G 6  
{ KM^}d$x}s  
nStartPos = input.readLong(); @Y(7n/*  
nEndPos = input.readLong(); l#w0-n%S  
} $SniQ  
input.close(); GIR12%-EO  
} ]i `~J  
catch(IOException e){e.printStackTrace ();} +_f813$C  
catch(Exception e){e.printStackTrace ();} la]Zk  
} s <$*A;t  
}y*rO(cu7G  
Q2@yUDd!  
private void processErrorCode(int nErrorCode)  M[R'  
{ N$ 2Iz  
System.err.println("Error Code : " + nErrorCode); Dl}va  
} IY2f$YV  
sP8_Y,  
@Hp=xC9V  
//停止文件下载 j2n 4; m  
public void siteStop() J+hifO  
{ X%B2xQM 5  
bStop = true; ^c sOXP=Yp  
for(int i=0;i<nStartPos.length;i++) 8{CBWXo$)  
fileSplitterFetch.splitterStop(); _9iF`Q  
q }9n.  
&23t/`   
} 2&F  H8  
} e#tWQM3  
//负责部分文件的抓取 z}7U>y6`  
**FileSplitterFetch.java 3 +D4$Y"  
*/ H.2aoZ-w  
package NetFox; 6b4]dvl_  
@Z9>E+udQ  
?T[K{t;~jo  
import java.io.*; ` B+Pl6l)F  
import java.net.*; |c,'0V,"cH  
xn7bb[g;  
]=]`Mnuxb  
public class FileSplitterFetch extends Thread { n(Ry~Xu_  
Ymg,NkiP0  
Ng1[y4R}  
String sURL; //File URL M j |"+(  
long nStartPos; //File Snippet Start Position -/6Ms%O  
long nEndPos; //File Snippet End Position {=E,.%8  
int nThreadID; //Thread's ID 7!8R)m^1[  
boolean bDownOver = false; //Downing is over H^w Inkf>  
boolean bStop = false; //Stop identical G\S_e7$ /  
FileAccessI fileAccessI = null; //File Access interface %0eVm   
brt` oR  
ZL- ` 3x  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException YoRD9M~iG~  
{ +0n,>eDjg^  
this.sURL = sURL; A)o%\j  
this.nStartPos = nStart; xo(3<1mD  
this.nEndPos = nEnd; Ns`:=  
nThreadID = id; ]4-t*Em  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 KHt#mQy)9  
} T Z@S?r>^  
m9 f[nT  
N< 7  
public void run() A ]~%<=b  
{ =:v5` :  
while(nStartPos < nEndPos && !bStop) (W $>!1~  
{ Ezw<  
uF\f>E)/N%  
.&c!k1kH  
try{ MG0d&[  
URL url = new URL(sURL); >WW5;7$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U~[ tp1Z)  
httpConnection.setRequestProperty("User-Agent","NetFox"); u69s}yZ  
String sProperty = "bytes="+nStartPos+"-"; -Mufo.Jz1o  
httpConnection.setRequestProperty("RANGE",sProperty); \"hP*DJ"  
Utility.log(sProperty); ,zH\&D$>u  
.ID9Xd$fky  
Ewczq1%l:  
InputStream input = httpConnection.getInputStream(); a'A'%+2  
//logResponseHead(httpConnection); E,:E u<  
T6p2=o&p  
91j.%#[v'  
byte[] b = new byte[1024]; wDS(zG   
int nRead; [^E{Yz=8,  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) |+(Hia,X  
{ 8 n)3'ok  
nStartPos += fileAccessI.write(b,0,nRead); \KPwh]0  
//if(nThreadID == 1) /2e,,)4g  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LuW^Ga"E  
} ?>o|H-R~5Z  
.LHzaeJCX  
7F D.3/  
Utility.log("Thread " + nThreadID + " is over!"); nfzKUJY  
bDownOver = true; Pi:=0,"XOp  
//nPos = fileAccessI.write (b,0,nRead); {oc7Chv=/H  
} /QCyA%y  
catch(Exception e){e.printStackTrace ();} 04cNi~@m  
} :#zv,U&OC  
} >n^[-SWJCT  
n^Sc*7  
qQ "O;_  
//打印回应的头信息 f.y~Sew  
public void logResponseHead(HttpURLConnection con) 9 ]W4o"  
{ =)Q0=!%-  
for(int i=1;;i++) '=eE6=m^K  
{ =3Hv  
String header=con.getHeaderFieldKey(i); <E.$4/T  
if(header!=null) :Y;\1J<b1  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); C2 ] x  
Utility.log(header+" : "+con.getHeaderField(header)); %!e;sL~&  
else :},/ D*v  
break; \4e6\6 +  
} znl_~:.4]X  
} k_<8SG+`  
h8lI# Gs  
^9C9[$Q  
public void splitterStop() j L[ hB  
{ AE"E($S`  
bStop = true; d(-$ { c  
} gwepaW  
-'OO6mU  
WaRYrTDv64  
} [d_sd  
on q~wEr  
Xqac$%[3  
/* HBFuA.",  
**FileAccess.java q;V1fogqI)  
*//文件访问(定位,写) U 0M>A  
package NetFox; !7K-Kqn  
import java.io.*; @Sl!p)  
\#A=twp  
CXs i  
public class FileAccessI implements Serializable{ !r8Jo{(pb  
9$xEktfV  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 2F[;Z*&  
RandomAccessFile oSavedFile; Z)U#5|sf  
long nPos; (qP !x 2j  
):_x  
UI4Xv  
public FileAccessI() throws IOException Mlpq2I_x  
{ y{eZrX|  
this("",0); 6L6Lk  
} 8elT/Wl  
KcB  ?[  
a`w)awb  
public FileAccessI(String sName,long nPos) throws IOException [^gSWU  
{ Xm`K@hJ@  
oSavedFile = new RandomAccessFile(sName,"rw"); XKsG2>l-W  
this.nPos = nPos; o4kNDXP#S  
oSavedFile.seek(nPos); g(:y_EpmLH  
} ~P5!VNJ;r  
nDvny0^a  
ubhem(p#  
public synchronized int write(byte[] b,int nStart,int nLen) fxLhVJ"b  
{ ^3`98y.Q  
int n = -1; @ %z5]w  
try{ ?.A6HrAPB  
oSavedFile.write(b,nStart,nLen); uF T\a=  
n = nLen; ftq~AF  
} }}qR~.[  
catch(IOException e) 9w Kz p  
{ r/Pg,si  
e.printStackTrace (); q9Y0Lk  
} 0;TMwE  
xiRTp:>  
j.C C.[$g  
return n; ? =IbiT  
} CWkm\=  
#G#gB   
oRu S_X  
} j7-#">YL  
t9pPG{1  
@V:b Co  
/* 4 qW)R{%  
**SiteInfoBean.java dm$:xE":  
*/ 72-@!Z0e  
package NetFox; V43JY_:  
. ~|^du<X  
dy`~%lX?  
public class SiteInfoBean { w#b~R^U  
"Ln\ZYB]  
;U`HvIch  
private String sSiteURL; //Site's URL b'-gy0  
private String sFilePath; //Saved File's Path hV8A<VT  
private String sFileName; //Saved File's Name cRg$~rYd  
private int nSplitter; //Count of Splited Downloading File 8'cDK[L  
mI`dZ3h  
%)aDh }  
public SiteInfoBean() Bv=Z*"Fv  
{//nSplitter的缺省值为5 2=3iA09px  
//default value of nSplitter is 5 Ta[}k/zW  
this("","","",5);  b'Uaj`Sn  
} )O&$-4gL'  
0^[$0]Mt[  
(8ymQ!aY  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) RZ.5:v6  
{ 5g&'n  
sSiteURL= sURL; er<~dqZ}]  
sFilePath = sPath; QnGJ4F  
sFileName = sName; XnG!T$  
this.nSplitter = nSpiltter; ?NwFpSB2  
(^Ln|3iz  
!9N%=6\  
} >ab=LDoM  
PHOW,8)dZh  
BW*zj=N%  
public String getSSiteURL() @)0g Xg  
{ +<|w|c  
return sSiteURL; ~gAx  
} v]1rH$  
7)]G"m{  
 6$Dbeb  
public void setSSiteURL(String value)  ~.Gk:M  
{ ~>EVI=?  
sSiteURL = value; "h#=ctCx"  
} 9!OpW:bR|  
&, )tD62s  
r9U1O@c  
public String getSFilePath() cP Y^Bf5)  
{ AuCVpDH  
return sFilePath; =wQ=`  
} 0'<S7?~|  
qnlj~]NV  
'F~u \m=E  
public void setSFilePath(String value) {J]|mxo  
{ &d2/F i+  
sFilePath = value; WZr~Pb9  
} 'SY &-<t(  
83 n: h08  
(/Mc$V  
public String getSFileName() %|I|Mc  
{ 8?$2;uGL  
return sFileName; K$Ph$P@   
} o?3R HP47  
O<hHo]jLF  
x<l1s  
public void setSFileName(String value) ^#4s/mdVO  
{ Dz{e@+>M  
sFileName = value; ymzm x$o=  
} j.6kjQN  
s*IfXv  
gU?)  
public int getNSplitter() V~=)#3]`[  
{ :QVGY^c  
return nSplitter; qkIU>b,B  
} qEAF!iB]L  
]VvJ1Xn0  
gY9"!IVe+  
public void setNSplitter(int nCount) pR"qPSv'  
{ #RF=a7&F  
nSplitter = nCount; (yP55PC O$  
} fo.m&mKgo  
} wGvgMZ]?'  
e0L;V@R  
D}T, z  
/* T?Y\~.+99  
**Utility.java Pio^5jhB6  
*/ L,6Y=?  
package NetFox; | 6>_L6t  
o$O,#^  
W%1S:2+Kl  
public class Utility { `y}d)"!  
jO 55<s94  
lIz_0rE  
public Utility() z(3"\ ^T  
{ qN@a<row&~  
j;)6uia*A  
^mi4q[PM  
} Y9;Mey*oW  
E: GJ$I  
//线程睡眠 4*x!B![]y  
public static void sleep(int nSecond) lQBM0|n  
{ ^>Y%L(>  
try{ ^%&x{F.  
Thread.sleep(nSecond); @@wx~|%  
} 1c#'5~nB  
catch(Exception e) >|)0Amt  
{ v=tj.Vg  
e.printStackTrace (); Yys~p2  
} bSf(DSqx  
} bZ.N7X PH  
@@IA35'tc  
//日志 "Vq]|j,B/c  
public static void log(String sMsg) U$)Hhn|X  
{ K//T}-Uub  
System.err.println(sMsg); /y)"j#-eW  
} G%!\ p:w  
6;cY!  
S |>$0P4W(  
public static void log(int sMsg)  J4"swPf  
{ {~fCqP.2  
System.err.println(sMsg); WEtA4zCO  
} 1~DD9z  
} Reu{   
V wVQ|UH  
RX5.bVp eE  
/* [fi'=Cb  
**TestMethod.java QaWHz   
*/ -I-Uh{)j  
package NetFox; ,6;xr'[o*  
Xexe{h4t_>  
JhCkkw  
public class TestMethod { GrR0RwnH)?  
hNnX-^J<o  
xDJ+BQ<1A  
public TestMethod() NOr <,  
{ ///xx/weblogic60b2_win.exe dAr)%RZ  
try{ ZQ~myqx,+L  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); rEyz|k:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c5E#QV0&v~  
SiteFileFetch fileFetch = new SiteFileFetch(bean); D2</^]3Su  
fileFetch.start(); LkGf|yd_  
} B>Cs&}Y!  
catch(Exception e){e.printStackTrace ();} `{U%[$<[W  
Ae j   
4r[pMJiq  
} $54=gRo^  
]eYd8s+  
"[*S?QO(L  
public static void main(String[] args) mA(nyF  
{ QSHJmk 6L  
new TestMethod(); &_9YLXtMi;  
} ;GE26Ymqly  
} %1\v7Xw{9  
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