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http断点续传简单实现(java)

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/* }Fu1Y@M%  
**SiteFileFetch.java gmH`XKi\  
*/ |Q)mBvvN  
package NetFox; '.z7)n  
import java.io.*; @2. :fK  
import java.net.*; eE'>kP}  
-4+'(3qr  
4+>yL+sC%v  
public class SiteFileFetch extends Thread { *cM=>3ws/  
uQH]  
0J/yd  
SiteInfoBean siteInfoBean = null; //文件信息Bean V0 {#q/q  
long[] nStartPos; //开始位置 D+;4|7s+  
long[] nEndPos; //结束位置 @&m]:GR  
FileSplitterFetch[] fileSplitterFetch; //子线程对象  m-4#s  
long nFileLength; //文件长度 >b"@{MZ@t  
boolean bFirst = true; //是否第一次取文件 ,N:^4A  
boolean bStop = false; //停止标志 ,w6?Ap  
File tmpFile; //文件下载的临时信息 X@[5nyILf  
DataOutputStream output; //输出到文件的输出流 iCpm^XT  
X7OU=+g  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) y _apT<P  
public SiteFileFetch(SiteInfoBean bean) throws IOException lHM} E$5  
{ 0~ nCT&V  
siteInfoBean = bean; Z<>gx m<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7r?,wM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Y>aVnixx<  
if(tmpFile.exists ()) U/{t "e  
{ sryA(V  
bFirst = false; X=-=z5  
read_nPos(); USEmD5q  
} {M:/HQo  
else <%3fJt-Ie  
{ CC!`fX6z>h  
nStartPos = new long[bean.getNSplitter()]; Pi=FnS  
nEndPos = new long[bean.getNSplitter()]; aWimg6q  
} |-vyhr 0  
0vLx={i  
1J1Jp|j.  
*A!M0TK?i,  
} A4(L47^  
XM!oN^  
DZL(G [  
public void run() i 7T#WfF  
{ }2S!;swg+  
//获得文件长度 6!0NFP~b  
//分割文件 _YR#J%xa  
//实例FileSplitterFetch cd,'37pZ  
//启动FileSplitterFetch线程 cHr]{@7Cs  
//等待子线程返回 YIW9z{rrs  
try{ XsJ`x  
if(bFirst) 'X+aYF }Ye  
{ H#GR*4x  
nFileLength = getFileSize(); pW8?EGO@  
if(nFileLength == -1) (9( xJ)  
{ %P1zb7:8  
System.err.println("File Length is not known!"); f 5bX,e)!  
} QE"$Lc)  
else if(nFileLength == -2) z5({A2q  
{ hoBFC1  
System.err.println("File is not access!"); l+6@,TY1U  
} 4J,6cOuW4  
else M6MxY\uM  
{ mQ}\ptdfV  
for(int i=0;i<nStartPos.length;i++) Eyf17  
{ 0P$19T N  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); XdIno}pN  
} \I i# R  
for(int i=0;i<nEndPos.length-1;i++) $#e}9g.  
{ (421$w,B%  
nEndPos = nStartPos[i+1]; M6cybEk`  
} n5xG4.#G  
nEndPos[nEndPos.length-1] = nFileLength; anz7ae&P'K  
} `::j\3B&Y-  
} pvt/{  
#q34>}O< O  
Z{(Gib~{N  
//启动子线程 ~7}no}7  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; sR PQr ?  
for(int i=0;i<nStartPos.length;i++) _d~GY,WTdO  
{ |:(BI5&S  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), k(>J?\iNW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), PNLlJlYlP  
nStartPos,nEndPos,i); 24InwR|^  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); OdyL j  
fileSplitterFetch.start();  A|IPQ=  
} jyg>'"W  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(),  gHUW1E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); >@4Ds"Ye"O  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 05 6yhB  
nEndPos = " + nFileLength); n$j B"1  
// fileSplitterFetch[nPos.length-1].start(); >Gg[J=7`  
aAoAjVNkK  
1:cq\Y  
//等待子线程结束 Y uZ  
//int count = 0; S WsD]rn  
//是否结束while循环 gDfM}2]/  
boolean breakWhile = false; 3H"F~_H  
p(4Ek"  
G@ybx[_[@  
while(!bStop) +A,cdi9z  
{ z&GGa`T"  
write_nPos(); PK?}hz  
Utility.sleep(500); D0f7I:i1  
breakWhile = true; S#+ _HFUK{  
K24y;968  
35-FD{  
for(int i=0;i<nStartPos.length;i++) *Z"Kvj;>u  
{ ZMyd+C_P2  
if(!fileSplitterFetch.bDownOver) aM[fag$c  
{ H-5f!>)  
breakWhile = false; Rx%kAt2X  
break; &#q%#M:  
} ~|KMxY(:  
} <N 80MU L|  
if(breakWhile) g5Hsz,x  
break; 0\$Lnwp_  
:]C\DUBo  
"J >, Hr9  
//count++; &:+_{nc,  
//if(count>4) 84Hm PPt  
// siteStop(); WFeaX7\b  
} #@5 jOi  
CA"`7<,  
4f0dc\$  
System.err.println("文件下载结束!"); GEb)nHQq  
} WWTJ%Rd|  
catch(Exception e){e.printStackTrace ();} yNx"Ey dk`  
} 1^;&?E  
<* PjG}Z.  
xi\uLu?i  
//获得文件长度 [qt^gy)  
public long getFileSize() v#sx9$K T  
{ 1 gRR  
int nFileLength = -1; .fW`/BXE  
try{ zgpPu4t  
URL url = new URL(siteInfoBean.getSSiteURL()); VKrKA71Z~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ]}0+7Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); / dn]`Ge)  
R91u6r#  
3^ &pb  
int responseCode=httpConnection.getResponseCode(); ]@1ncn7N  
if(responseCode>=400) RzSN,bL R  
{ 0$nJd_gW_  
processErrorCode(responseCode); U`'w{~"D%  
return -2; //-2 represent access is error :(x 90;DW  
} !C0= h  
b}q,cm  
WUi7~Ei}  
String sHeader; U(qM( E  
UuA=qWC  
]7"mt2Q=3  
for(int i=1;;i++) X]CaWxM  
{ gzdgnF2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 8|Y^z_C  
//Utility.log(in.readLine()); 8i"{GGVC  
sHeader=httpConnection.getHeaderFieldKey(i); {gi"ktgk  
if(sHeader!=null) *XzUqK  
{ u09OnP\  
if(sHeader.equals("Content-Length")) ~JT{!wcE}o  
{ eS Fmx  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ;6)|'3.B9  
break; CnA*o 8w  
} Kd,m;S\  
} XJOo.Y  
else anV)$PT=  
break; !8s:3]  
} khu,P[3>  
} !p9F'7;Y<  
catch(IOException e){e.printStackTrace ();} @fYA{-ZC  
catch(Exception e){e.printStackTrace ();} gf@'d.W}  
? 8!N{NV  
->#7_W  
Utility.log(nFileLength); @o^sp|k !  
AU$5"kBE  
%I=J8$B]f  
return nFileLength; 42Ffx?Qmv  
} {5z?5i ?D  
9hp0wi@W}  
,!py n<_  
//保存下载信息(文件指针位置) =O _[9kuJ  
private void write_nPos() da^9Fb  
{ ta 4<d)nB  
try{ /iQ>he~fy  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yq,5M1vR  
output.writeInt(nStartPos.length); @+!d@`w:z2  
for(int i=0;i<nStartPos.length;i++) EX5kF  
{ D 7E^;W)H  
// output.writeLong(nPos); Q Y fS-  
output.writeLong(fileSplitterFetch.nStartPos); !c`1~a!  
output.writeLong(fileSplitterFetch.nEndPos); ]V]o%onW  
} XF$C)id2p  
output.close(); bU,& |K/  
} BPOWo8TqD^  
catch(IOException e){e.printStackTrace ();} ) D`_V.,W  
catch(Exception e){e.printStackTrace ();} BZ T%+s;u9  
} &boBu^,94  
q.X-2jjpx:  
Zj^H3 h  
//读取保存的下载信息(文件指针位置) Ek. j@79  
private void read_nPos() Z,&ywMm/G  
{ 5LK>n-  
try{ 4%{m7CK}  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); \%VoX` B  
int nCount = input.readInt(); _0`O}  
nStartPos = new long[nCount]; .lnD]Q  
nEndPos = new long[nCount]; t2$:*PvE  
for(int i=0;i<nStartPos.length;i++) 3G&1. 8  
{ 8UZE C-K  
nStartPos = input.readLong(); Te/)[I'Tn  
nEndPos = input.readLong(); Y+7v~/K=  
} Fy@D&j  
input.close(); d$Xvax,C  
} - |'wDf?H  
catch(IOException e){e.printStackTrace ();} 1f:k:Y9i  
catch(Exception e){e.printStackTrace ();} {gn[ &\  
} jHZ<G c  
@'y"D  
$7*Ml)H!9  
private void processErrorCode(int nErrorCode) X[[=YCi0  
{ m1hf[cg  
System.err.println("Error Code : " + nErrorCode); mnia>; 0H  
} J{ Vl2P?@  
#75;%a8  
Mf63 59  
//停止文件下载 tpctz~ .  
public void siteStop() *dl@)~i  
{ ,O+7nByi[V  
bStop = true; ] ge-b\  
for(int i=0;i<nStartPos.length;i++) `F@yZ4L3S  
fileSplitterFetch.splitterStop(); M/qiA.C@W  
N@>S>U8C  
EIfrZg7R  
} o_5@R+&  
} PTh Ya  
//负责部分文件的抓取 s5dh]vNN  
**FileSplitterFetch.java Lsz`nD5  
*/ a`uT'g[*  
package NetFox; \CGcP  
x@ O:  
$b$D[4  
import java.io.*; }R x%&29&  
import java.net.*; {%Y7]*D  
4SrK]+|  
^s*} 0  
public class FileSplitterFetch extends Thread { )wRD  
{ 1+H\ (v  
FRW.  
String sURL; //File URL #wyS?FP-  
long nStartPos; //File Snippet Start Position UTt#ltun?  
long nEndPos; //File Snippet End Position Id0F2  [  
int nThreadID; //Thread's ID ;a`X|N9  
boolean bDownOver = false; //Downing is over ~83P09\T%  
boolean bStop = false; //Stop identical 1DP)6{x  
FileAccessI fileAccessI = null; //File Access interface yN.D(ZwF:  
G dU W$.  
,L;vN6~  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ;<A/e  
{ 5dk,!Cjg  
this.sURL = sURL; YovY0nO  
this.nStartPos = nStart; v=>Gvl3&U  
this.nEndPos = nEnd; URgF8?n  
nThreadID = id; pS \>X_G3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 AngwBZ@  
} #`$7$Y~]  
Xn=fLb(  
K;l'IN"N  
public void run() :S12=sFl$  
{ ?+\,a+46P_  
while(nStartPos < nEndPos && !bStop) \YS?}! 0  
{ nz\fN?q  
rWXW}Yg  
|9I;`{@  
try{ O)R0,OPb  
URL url = new URL(sURL); F?kVW[h?q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @El<"\  
httpConnection.setRequestProperty("User-Agent","NetFox"); *@nUas 2"  
String sProperty = "bytes="+nStartPos+"-"; ?s]`G'=>V`  
httpConnection.setRequestProperty("RANGE",sProperty); `,Gk1~Wv  
Utility.log(sProperty); [ UJj*n  
)QD}R36Ic  
`9l\ ~t(M  
InputStream input = httpConnection.getInputStream(); $ Zr,-  
//logResponseHead(httpConnection); ise}> A!t  
@U JmbD{  
z sPuLn9G  
byte[] b = new byte[1024]; )|x5#b-lz  
int nRead; lijy?:__  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) cG:`Zj~4  
{ d ] ;pG(  
nStartPos += fileAccessI.write(b,0,nRead); $NH Wg(/R@  
//if(nThreadID == 1) pt#[.n#f  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |5Pbc&mH8A  
} kVv <tw  
}q W aE  
k;5}@3iQ  
Utility.log("Thread " + nThreadID + " is over!"); r.;iO0[/  
bDownOver = true; Rjl__90  
//nPos = fileAccessI.write (b,0,nRead); :F=nb+HZ  
} H)Ge#=;ckQ  
catch(Exception e){e.printStackTrace ();} 8)8oR&(f  
} sIsu >eL  
} p%1m&/ `F  
[!mjUsut*  
1.uQ(>n  
//打印回应的头信息 su;S)yZb  
public void logResponseHead(HttpURLConnection con) a7G2C oM8  
{ di2=P)3  
for(int i=1;;i++) Y;Gm,  
{ YPnJldVn  
String header=con.getHeaderFieldKey(i); u0b-JJ7)BQ  
if(header!=null) 1,'^BgI,  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); -d'|X`^nE  
Utility.log(header+" : "+con.getHeaderField(header)); GN c|)$  
else ,0]28 D  
break; nn4Sy,cz  
} I;H9<o5  
} wf%Ep#^6}  
A> A'dQ69  
>r3< O=Z7  
public void splitterStop() 5Suc#0y  
{ ot#kU 8f  
bStop = true; 79g>7<vp  
} 0f/!|c  
, % jTXb  
oH0F9*+W  
} 3G|fo4g  
Y26l,XIV  
`0|&T;7  
/* L$ Ar]O)  
**FileAccess.java J6D$ i+  
*//文件访问(定位,写) Ilb |:x"L  
package NetFox; N06O.bji  
import java.io.*; agT[y/gb  
PM!t"[@&  
TR_oI<xB2  
public class FileAccessI implements Serializable{ C /XyDbH  
_C=[bI@  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >0#q!H,X  
RandomAccessFile oSavedFile; d ovwB`5  
long nPos; ^l&4UnLlc  
ky$:C,1t  
^) ^|;C\`  
public FileAccessI() throws IOException W r7e_  
{ _kX/LR"L+  
this("",0); %uqD\`-  
} +\vY;!^  
BV?N_/DXp  
e7qMt[.  
public FileAccessI(String sName,long nPos) throws IOException M;V#Gm  
{ s^'#"`!v=  
oSavedFile = new RandomAccessFile(sName,"rw"); M`pTT5r  
this.nPos = nPos; 4~YQ\4h=  
oSavedFile.seek(nPos); Prz +kPP  
} :k(t/*Nl3  
E/$@ud|l"  
LE80`t>M#  
public synchronized int write(byte[] b,int nStart,int nLen) *1S.9L  
{ *N e2l`!1m  
int n = -1; }SN44 di(  
try{ =M{CZm  
oSavedFile.write(b,nStart,nLen); } %CbZ/7&  
n = nLen; T-2p`b}h W  
} o\;"|O}  
catch(IOException e) N<"6=z@w+  
{ {&u7kWD|  
e.printStackTrace (); T^;Jz!e  
} ss@}Dt^  
He-Ja  
UJ)M:~O  
return n; O8~U<'=*  
} JX$NEq(  
(g2r\hI  
NF(IF.8G  
} XAxI?y[c  
^ O Xr: P  
JKi@Kw  
/* ;4v}0N~.  
**SiteInfoBean.java P9mxY*K)%5  
*/ "q>I?UcZ  
package NetFox; EJ;0ypbG  
$F`<&o  
)bXx9,VL  
public class SiteInfoBean { akc"}+-oX  
r,@X>_}  
2G}7R5``9  
private String sSiteURL; //Site's URL 4[CBW  
private String sFilePath; //Saved File's Path \g:qQ*.  
private String sFileName; //Saved File's Name fy=C!N&/  
private int nSplitter; //Count of Splited Downloading File p2c=;5|/Q  
$N+ {r=  
hB$Y4~T%  
public SiteInfoBean() m/c&/6nk  
{//nSplitter的缺省值为5 9_A0:S9Z  
//default value of nSplitter is 5 /xm#:+Sc  
this("","","",5); :;*#Qh3"  
} s.I1L?s1w?  
lPcVhj6No%  
5az 4NT  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) . (*kgv@3x  
{ H^PqYLj N  
sSiteURL= sURL; _ kSPUP5  
sFilePath = sPath; +V+*7s%fL  
sFileName = sName; r~G]2*3  
this.nSplitter = nSpiltter; h[ZN >T  
A;WwS?fyQ  
[T[9*6Kt  
} 6:@t=C  
 e(;`9T  
'UvS3]bSYW  
public String getSSiteURL() @wdB%  
{ qzlMn)e  
return sSiteURL; zhX`~){N6  
} HMS9y%zl/  
:OQ:@Yk  
$,QpSK`9i  
public void setSSiteURL(String value) E4v_2Q -w  
{ #u<o EDQ  
sSiteURL = value; 51ajE2+X&  
} U_}A{bFG  
sAD P~xvU  
K)Xs L  
public String getSFilePath() W]yClx \  
{ +/!=Ub[:U  
return sFilePath; (&P0la 1  
} gR-Qj  
[#>$k 6F*  
ZP6 3Alt  
public void setSFilePath(String value) u_6BHsU  
{ Iz GB  
sFilePath = value; R<lNk<  
} ]zvVY:v  
+>!B(j\gx  
-Nlf~X  
public String getSFileName() Dd5xXs+c  
{ }rY?=I  
return sFileName; }$0xt'q&  
} QLB1:O>  
g<rKV+$6  
inPdV9  
public void setSFileName(String value) =(|xU?OL  
{ C7jc6(> m  
sFileName = value; JwI`"$ > w  
} ,na=~.0R:  
N,/BudF o  
L'\/)!cEd  
public int getNSplitter() 8R)D! 7[l  
{ 3m43nJ.~  
return nSplitter; "'F;lzq  
} 0Y6q$h>4  
gP %|:"  
znQ'm^h  
public void setNSplitter(int nCount) `j}_BW_  
{ _Vo)<--+I  
nSplitter = nCount; 'Wf?elB+  
} 1A?\BJ"  
} 5U)ab3 :  
}#ep}h  
#j^('K|  
/* >9.5-5"   
**Utility.java Wiq{wxe  
*/ 0j{F^rph  
package NetFox; joChML_  
O/D Af|X|  
mZbWRqP[|_  
public class Utility { cZDxsd]  
9RCO|J  
%R.xS} Q  
public Utility() @ kJ0K  
{ w*<Y$hnBzF  
GJIWG&C03  
%_b^!FR  
} Q$|^~  
R,x>$n  
//线程睡眠 GP[6nw_'^  
public static void sleep(int nSecond) N ;Z`%&  
{ *?^Z)C>  
try{ Sg.+`xww3  
Thread.sleep(nSecond); }x kLD!  
} C5PmLiOHY>  
catch(Exception e) 4-7kS85  
{ |RR%bQ^{  
e.printStackTrace (); `%t$s,TiP  
} A$%Q4jC}  
} >Lw}KO`  
UTDcX  
//日志 5!'R'x5e  
public static void log(String sMsg) HDF!`  
{ E\]OySC%C$  
System.err.println(sMsg);  Y8)E]D  
} p~Hvl3SxR  
4AY _#f5u  
*<*0".#  
public static void log(int sMsg) NI5]Nz<?  
{ -,~;qSs  
System.err.println(sMsg); %s$rP  
} w~kHQ%A  
} ioC@n8_[G  
~Na=+}.q_  
a -xW8  
/* "t[M'[ `C  
**TestMethod.java On{~St'V  
*/ !;o\5x<'$O  
package NetFox; ]ZzoJ7lr  
$?FS00p*|X  
7$!`p,@we/  
public class TestMethod { AIZW@Nq.5  
"wA0 LH_  
 20I4r  
public TestMethod() a'@-"qk  
{ ///xx/weblogic60b2_win.exe $uEJn&n7}  
try{ Z69+yOJI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); t6'61*)|0  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ! jbEm8bt  
SiteFileFetch fileFetch = new SiteFileFetch(bean); _Kc 1  
fileFetch.start(); Dh2:2Rz=#7  
} 2.[_t/T  
catch(Exception e){e.printStackTrace ();} "| K f'/r  
\*f;!{P{  
az0cS*@  
} Vh"MKJ'R^  
9o-!ecx}  
 28nmQ  
public static void main(String[] args) Gs[Vu@*  
{ <jbj/Q )"  
new TestMethod(); Wgxn`6  
} /Zo~1q  
} P3'2IzNw  
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