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http断点续传简单实现(java)

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/* |h6u%t2AY  
**SiteFileFetch.java ![l`@NH[U  
*/ )@,zG(t5;  
package NetFox; q0y#Y  
import java.io.*; KW 78J~u+  
import java.net.*; $[1J[eY*  
$ctpg9 7  
1X,\:F.-+  
public class SiteFileFetch extends Thread { XK=-$2n  
- D&d1`N4  
EjDr   
SiteInfoBean siteInfoBean = null; //文件信息Bean qQ T ^d  
long[] nStartPos; //开始位置 Mr6q7  
long[] nEndPos; //结束位置 D%%@+3a  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 HV}*}Ty  
long nFileLength; //文件长度 NB=!1;^J  
boolean bFirst = true; //是否第一次取文件  Bl1^\[#  
boolean bStop = false; //停止标志 ?Fp2W+M j  
File tmpFile; //文件下载的临时信息 'irHpN6n  
DataOutputStream output; //输出到文件的输出流 nSR<(-j!  
1 LUvs~Qu  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) *ud/'HR8]  
public SiteFileFetch(SiteInfoBean bean) throws IOException t8_i[Hw6D  
{ RJ0:O   
siteInfoBean = bean; f~ -qjEWm  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); X*QQVj  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 2Cgq&\wS  
if(tmpFile.exists ()) eX3|<Bf  
{ 3@8Zy:[8<  
bFirst = false; (\o &Gl  
read_nPos(); <#%kmYSL  
} CjT]!D)s  
else E~K5n2CI  
{ l1uv]t <  
nStartPos = new long[bean.getNSplitter()]; $_orxu0W  
nEndPos = new long[bean.getNSplitter()]; &(/QJ`*8  
} 7S.E,\Tws  
sOb=+u$$9  
m(rd\3d  
&++tp5  
}  <R.Ipyt.  
qtYVX:M@,  
h'|J$   
public void run() gWLhO|y  
{ ^w6~?'}  
//获得文件长度 cOrFe;8-.  
//分割文件 GX,)~Syw*  
//实例FileSplitterFetch =?oYEO7  
//启动FileSplitterFetch线程 sMHP=2##  
//等待子线程返回 uz'MUT(68  
try{ <4,LTB]9-  
if(bFirst) sHn-#SGm  
{ gl>%ADOB@  
nFileLength = getFileSize(); ;{:bq`56f  
if(nFileLength == -1) [\,Jy8t)\  
{ U{?#W  
System.err.println("File Length is not known!"); ibL    
} d*tn&d~k,  
else if(nFileLength == -2)  Lxqv  
{ k?VH4 yA  
System.err.println("File is not access!"); .z}*!   
} *)xjMTJ%  
else ;tG@ 6  
{ \@F~4,VT  
for(int i=0;i<nStartPos.length;i++) |Q*OA  
{ HBiUp$(mB  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); eccJt  
} F$nc9x[S  
for(int i=0;i<nEndPos.length-1;i++) u.9syr  
{ "*JyNwf  
nEndPos = nStartPos[i+1]; p|RFpn2ygF  
} \wM8I-f!  
nEndPos[nEndPos.length-1] = nFileLength; <&MY/vV  
} F*J@OY8i  
} z( ^ r  
8/BWe ;4  
!63]t?QXMG  
//启动子线程 owKOH{otf  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; &E0L 2gbI  
for(int i=0;i<nStartPos.length;i++) Q1^kU0M}  
{ v)s; wD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), cVuT|b^  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 9`Zwa_Tni  
nStartPos,nEndPos,i); 45U!\mG  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ? uu,w  
fileSplitterFetch.start(); V8-*dE  
} 'wd&O03&  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~Hb2-V  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); t*(buAx  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", @;`d\lQ  
nEndPos = " + nFileLength); "U o~fJ  
// fileSplitterFetch[nPos.length-1].start(); BVe c  
Y"UB\_=  
u=f}t=3  
//等待子线程结束 D V=xqC6}  
//int count = 0; |$G|M=*LN  
//是否结束while循环 =l+~}/7'Z  
boolean breakWhile = false; D0VbD" y  
6`V~cVu  
[Nv)37|W  
while(!bStop) g\Akf  
{ ..;ep2jSs  
write_nPos(); s_4y^w]aX  
Utility.sleep(500); "pTU&He  
breakWhile = true; ),5|Ves;t[  
cg).b?g  
&at>sQ'  
for(int i=0;i<nStartPos.length;i++) B'8T+qvA  
{ 91\]Dg  
if(!fileSplitterFetch.bDownOver) M&J$9X  
{ 'h3yxf}\  
breakWhile = false; r O-=):2  
break; K_o[m!:jU  
} ':#DROe!  
} :)DvZxHE@  
if(breakWhile) ^ RIWW0  
break; h)pYV>!d  
qt`HP3J&  
3F?_{A  
//count++; !~ fy".|x  
//if(count>4) M+GtUE~"  
// siteStop(); F42?h:y8I  
} ^2 \-zX!bt  
,?(U4pzX  
O*udVE>  
System.err.println("文件下载结束!"); 6~tj"34_  
} BXa.XZ<n(  
catch(Exception e){e.printStackTrace ();} 9^1li2zk{  
} @~C C$Y$  
h%8C_m A  
o@uZU4MM  
//获得文件长度 y7U?nP ')+  
public long getFileSize() g[ O6WZ!F_  
{  4 `]  
int nFileLength = -1; $8WeWmY  
try{ Rg%Xy`gS  
URL url = new URL(siteInfoBean.getSSiteURL()); :b"&Rc&s.  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Hh`HMa'q  
httpConnection.setRequestProperty("User-Agent","NetFox"); >TG#  
-fT}Nj\  
7_CX6:  
int responseCode=httpConnection.getResponseCode(); 80"oT'ZFh  
if(responseCode>=400) 3='Kii=LA  
{ bEB9J- Q  
processErrorCode(responseCode); +O!4~k^  
return -2; //-2 represent access is error (o518fmR  
} +6Ye'IOG  
rbc7CPq_^  
35n'sVn  
String sHeader; Zy=DY  
]/{iIS_  
V@pUU~6R  
for(int i=1;;i++) m_h$fT8 _  
{ Wiere0 2*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }S 6h1X  
//Utility.log(in.readLine()); )*nZ6Cg'  
sHeader=httpConnection.getHeaderFieldKey(i); {-1N@*K  
if(sHeader!=null) y,Z2`Zmu  
{ ("P]bU+'>  
if(sHeader.equals("Content-Length")) h.4FY<  
{ DA^!aJ6iF  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Ib2n Bg>j  
break; L3Ivm :  
} .Z(Q7j^  
} pMV?vH  
else *X8Pa ;x  
break; +c' n,O~3  
} !112u#V  
}  I|. <  
catch(IOException e){e.printStackTrace ();} Yd]  
catch(Exception e){e.printStackTrace ();} a^7QHYJ6  
R#4f_9e<Z  
cf%aOHYI*  
Utility.log(nFileLength); E'^ny4gL  
8u7QF4 Id  
<[' ucp  
return nFileLength; d"OYq  
} 3hfv^H  
Qb8Z+7  
o]@'R<F(u  
//保存下载信息(文件指针位置) ?G 'sb}.  
private void write_nPos() K)GpQ|4:<  
{ ?^WX] SAl  
try{ wo9`-o6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); S~U5xM^s  
output.writeInt(nStartPos.length); OlX#1W]  
for(int i=0;i<nStartPos.length;i++) -%TwtO<$']  
{ rm4t  
// output.writeLong(nPos); V(;c#%I2  
output.writeLong(fileSplitterFetch.nStartPos); DWupLJpk;c  
output.writeLong(fileSplitterFetch.nEndPos); +do* C =z  
} RmJ|g<  
output.close(); J~)JsAXAI  
} ^f9>tI{  
catch(IOException e){e.printStackTrace ();} `$XgfMBf |  
catch(Exception e){e.printStackTrace ();} #6mr'e1  
} XwDt8TxL  
8 @r>`c  
>%A~ :  
//读取保存的下载信息(文件指针位置) y(X^wC  
private void read_nPos() S^{tRPF%d  
{ c3(0BSv  
try{ s:ojlmPb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); &'u%|A@  
int nCount = input.readInt(); ';LsEI[  
nStartPos = new long[nCount]; <K <|G  
nEndPos = new long[nCount]; FTu<$`!1L  
for(int i=0;i<nStartPos.length;i++) &Z%'xAOGR  
{ *1h@Jb34  
nStartPos = input.readLong(); 0u bf]Z  
nEndPos = input.readLong(); SK 5__Ix  
} y\R-=Am".  
input.close(); :PNhX2F  
} \jr-^n]  
catch(IOException e){e.printStackTrace ();} #g~]2x  
catch(Exception e){e.printStackTrace ();} S e|h]+G  
} |8fdhqy_  
FpZ5@  
+de5y]1H,|  
private void processErrorCode(int nErrorCode) 4iY <7l8  
{ 1rV9dM#F  
System.err.println("Error Code : " + nErrorCode); 7pM&))R  
} Y4N)yMSl"  
e#@u&+K/f  
Rm Q>.?  
//停止文件下载 /w2NO9Q  
public void siteStop() *~^%s +b  
{ j]m|}n  
bStop = true; -BH T'zq1S  
for(int i=0;i<nStartPos.length;i++) dTqL[?wH?  
fileSplitterFetch.splitterStop(); 4KY@y?H g  
}[OEtd{  
5uU{!JuSa  
} |;R-q8  
} )2J#pz?.  
//负责部分文件的抓取 i}@5<&J  
**FileSplitterFetch.java CJ[e^K{  
*/ Lbu,VX  
package NetFox; ' wKTWmf?\  
}DQ[C&  
N@8tf@BT   
import java.io.*; ;0}C2Cz'  
import java.net.*; 2ZKy7p0/  
:-~x~ah-  
KJ_L>$ ]*  
public class FileSplitterFetch extends Thread { |UN#utw{^Y  
A/.z. K  
CFeAKjG  
String sURL; //File URL *2Q x69`  
long nStartPos; //File Snippet Start Position *-gmWATC6  
long nEndPos; //File Snippet End Position `tm(3pJ  
int nThreadID; //Thread's ID Y^gIvX  
boolean bDownOver = false; //Downing is over j&0t!f.Rv  
boolean bStop = false; //Stop identical q,]57s  
FileAccessI fileAccessI = null; //File Access interface MT<3OKo?:  
0p=  
Jo9c|\4  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException PRK*7-(  
{ EC?U#!kv  
this.sURL = sURL; Tx/KL%X  
this.nStartPos = nStart; !={QL:  
this.nEndPos = nEnd; 6e;8\1^  
nThreadID = id; -;$jo-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 w^/"j_p@  
} ;h#CT#R2  
$'bb)@_  
M B,Z4 ^  
public void run() dfs1BV'  
{ z_a7HCG2  
while(nStartPos < nEndPos && !bStop) i>;6Z s>S  
{ _RX*Ps=  
D66!C{  
=A; 79@bY  
try{ j4h?"  
URL url = new URL(sURL); ; .hTfxE0  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]v.Yt/&C{  
httpConnection.setRequestProperty("User-Agent","NetFox"); >|JMvbje  
String sProperty = "bytes="+nStartPos+"-"; sE0,b  
httpConnection.setRequestProperty("RANGE",sProperty); O9Yk5b;  
Utility.log(sProperty); ? \NT'CG  
E9j(%kQ2  
eb<' >a  
InputStream input = httpConnection.getInputStream(); g= s2t"&  
//logResponseHead(httpConnection); X($@E!|  
,@t#)HV  
(ce"ED`1  
byte[] b = new byte[1024]; =[o/D0-Kn  
int nRead; 0*o=JM]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) G[!<mh4h|  
{ a0Q\]S  
nStartPos += fileAccessI.write(b,0,nRead); Cv qUaHW@  
//if(nThreadID == 1) KQ.cd]6  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IFWP&20  
} ~<[]l~`  
O9F#gO|!  
Y+"Gx;F>  
Utility.log("Thread " + nThreadID + " is over!"); JDBNi+t  
bDownOver = true; }fz;La:b  
//nPos = fileAccessI.write (b,0,nRead); *1_A$14 l  
} 9R4q^tGR\  
catch(Exception e){e.printStackTrace ();} 5<?/M<i  
} ]BBjFs4#  
} ]yA_N>k2K  
t8-LPq  
!_h<w?)  
//打印回应的头信息 }Yp]A  
public void logResponseHead(HttpURLConnection con) HO;,Ya^l  
{ }pv<<7}|  
for(int i=1;;i++) U KdCG.E9^  
{ jI807g+  
String header=con.getHeaderFieldKey(i); vC5y]1QDd  
if(header!=null) CB?,[#r5f  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ,T7(!)dR  
Utility.log(header+" : "+con.getHeaderField(header)); L!kbDbqn  
else )nUTux0K\  
break; Y--Uo|H  
} xsXf_gGu  
} D~%h3HM  
pw1&WP&?3  
{NV=k%MTmi  
public void splitterStop() -Tr*G4  
{ xr-v"-  
bStop = true; j es[a  
} cGe-|>:  
JU0|pstf  
)L:p.E  
} u< .N\/  
X3rvM8  
Q GDfX_  
/* kM/;R)3t4/  
**FileAccess.java ;923^*\:F{  
*//文件访问(定位,写) Mhze !!  
package NetFox; b `.h+=3  
import java.io.*; JV9Ft,xk  
X.!|#FWb+  
8Wyv!tL  
public class FileAccessI implements Serializable{ I;Bcim;  
OAtn.LU  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 *|k/lI  
RandomAccessFile oSavedFile; i fbO<  
long nPos; &(HIBF'O  
8&9'1X5)8_  
;yg9{"O  
public FileAccessI() throws IOException 2:& [r*  
{ 2u'h,on?  
this("",0); "WHt9 yZ  
} 4';(\42  
bO?Us  
C\p _  
public FileAccessI(String sName,long nPos) throws IOException }z8HS< #Q  
{ `=cOTn52  
oSavedFile = new RandomAccessFile(sName,"rw"); m;KD@E!  
this.nPos = nPos; 8?&u5  
oSavedFile.seek(nPos); .m\'|%  
} ^{Y9!R*9U*  
0|_d{/VK4  
 6,;7iA]  
public synchronized int write(byte[] b,int nStart,int nLen) %{M&"Mv  
{ :0RfA%  
int n = -1; U49 `!~b7  
try{ +cnBEv~y  
oSavedFile.write(b,nStart,nLen); RP4P"m(   
n = nLen; I<ta2<h  
} A VbGJ+  
catch(IOException e) ygquQhf5  
{ kI>PaZ`i)  
e.printStackTrace (); ThSB\  
} wsLfp82  
fbK`A?5K  
x4vowF  
return n; vtVc^j4  
} /xcl0oe(  
2k$~Mv@L  
Qcf5* ]V  
} )j>BvO  
<i!7f26r  
CA{(x(W\:  
/* COf>H0^%Q  
**SiteInfoBean.java .IJgkP)!]  
*/ ESAFsJ$r;  
package NetFox; [Vaw$c-+[y  
6:vdo~  
Xm! ;  
public class SiteInfoBean { WMLsKoby  
i5 F9*  
R87e"m/C%  
private String sSiteURL; //Site's URL B> LL *  
private String sFilePath; //Saved File's Path  9> k-";  
private String sFileName; //Saved File's Name fer~NlX  
private int nSplitter; //Count of Splited Downloading File o7W1sD1O  
\6U$kMGde  
$pg1Av7l  
public SiteInfoBean() yl[6b1  
{//nSplitter的缺省值为5 bM"crRG"  
//default value of nSplitter is 5 e2PM^1{_  
this("","","",5); `vPc&.-K  
} w,QO!)j!  
0'9z XJ"  
%>G(2)Fb\\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) >1n[Y- r  
{ H(TY.  
sSiteURL= sURL; ]TmxCTVL  
sFilePath = sPath; !:^lTvYWZH  
sFileName = sName; q|+`ihut  
this.nSplitter = nSpiltter; T[YGQT|B  
B:Xmc,|,  
7#BU d/  
} ()>,L? y  
%!i|"FNc  
7pY7iR_  
public String getSSiteURL() C`0;  
{ M@/Hd0$  
return sSiteURL; ^ |^Q(  
} LiF(#OuZ  
`:I<Jp  
h NCoX*icd  
public void setSSiteURL(String value) ZOK,P  
{ f2"1^M  
sSiteURL = value; nBA0LIb  
} ?{ 0MF  
WTcrfs)T  
hvS4"% \  
public String getSFilePath() Zh]FL8[ nc  
{ (haYY]W\  
return sFilePath; @m=xCg.Z  
} b&V}&9'[M;  
_26<}&]b*  
=R  <X!@  
public void setSFilePath(String value) /T_ G9zc  
{ c= }#8d.  
sFilePath = value; LZB=vc|3/  
} 5fdB<& 9  
XOe8(cXa9  
j}CZ*  
public String getSFileName() G-)Q*p{i|  
{ %;r0,lN|II  
return sFileName; [0(+E2/:2  
} o=1M<dL  
M;{btu^a  
kq SpZoV0'  
public void setSFileName(String value) Nn_n@K  
{ zNs8yMnFr  
sFileName = value; J}9 I5O  
} DhAQ|SdCf  
A80r@)i  
tX$ v)O|  
public int getNSplitter() #0WGSIht<  
{ Jmp%%^  
return nSplitter; n!r<\4I  
} _U"9#<  
Whd2mKwiO  
;ss,x  
public void setNSplitter(int nCount) uq>\pO&P  
{ &pCNOHi|  
nSplitter = nCount; [a<u cJ  
} XPhC*r  
} )r)3.|wJm  
H 40~i=.  
/2!Wy6 p  
/* 5VU 5kiCt  
**Utility.java 8 pQx6QE  
*/ OUd&fUmH  
package NetFox; QD6in>+B@  
(Mk9##R#  
|Mj2lZS  
public class Utility { (W~')A"hC'  
FG^ Jh5  
ld-Cb 3R^  
public Utility() 6,707h  
{ '9+JaB  
`n*e8T  
V5MLzW\8  
} %q~YJ*\  
e-Xr^@M*Q  
//线程睡眠 nNCG*Vu  
public static void sleep(int nSecond) fr\"MP  
{ H}R/_5g  
try{ {!lC$SlJ  
Thread.sleep(nSecond); :/c40:[  
} DcO$&)Eb  
catch(Exception e) }-ly'4=l  
{ L*Gk1'  
e.printStackTrace (); wN|;_~h2  
} 6`tc]a"#Zb  
} Rd?8LLz  
6%hr]>L  
//日志 7wivu*0  
public static void log(String sMsg) Y;X_E7U  
{ m5wfQ_}}ss  
System.err.println(sMsg); yh  
} (Q_J{[F  
fd{75J5%  
b"lzR[X,e  
public static void log(int sMsg) Y+,ii$Ce~  
{ A)2eo<ij4  
System.err.println(sMsg); Ej\M e  
} k$kOp *X  
} ;.O#|Z[  
xnuu#@f  
qT<OiIMj^  
/* KI@OEy  
**TestMethod.java 4jOq.j  
*/ 5Iql%~_x  
package NetFox; m a!rZ n  
9h Jlc  
I`$"6 Xy  
public class TestMethod { ma +iIt;  
Y<4%4>a  
-x~4@~  
public TestMethod() X]Aobtz  
{ ///xx/weblogic60b2_win.exe N)kZ2|oD  
try{ kB2]Z}   
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P}2i[m.*,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 3 #8bG(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); f: j9ze  
fileFetch.start(); G^G= .9O  
} >@g+%K]  
catch(Exception e){e.printStackTrace ();} HX;JO[0  
9!``~]G2  
_~l*p"PL<  
} ;p/%)WW  
`X["Bgk$!T  
S%^*h{9u"  
public static void main(String[] args) %kHeU=  
{ % `4\ 8H`  
new TestMethod(); ;?{N=x8  
} vKcZgIR  
} IL]Js W  
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