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http断点续传简单实现(java)

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/* @pytHN8( $  
**SiteFileFetch.java ./#K@V1  
*/ Y+/ofk "  
package NetFox; =Z#tZ{"  
import java.io.*; A6iyJFm D  
import java.net.*; i=o>Bl@f  
HxZ4t  
<py~(q  
public class SiteFileFetch extends Thread { 5 1 x^gX|  
ui9gt"qS`  
+6gS]  
SiteInfoBean siteInfoBean = null; //文件信息Bean b@1QE  
long[] nStartPos; //开始位置 7azxqa5:  
long[] nEndPos; //结束位置 2#/ KS^  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]Wd{4(b  
long nFileLength; //文件长度 42z9N\ f  
boolean bFirst = true; //是否第一次取文件 ?N11R?8  
boolean bStop = false; //停止标志 7MGc+M(p  
File tmpFile; //文件下载的临时信息 ,z%F="@b9  
DataOutputStream output; //输出到文件的输出流 Crpk q/M  
::TUSz2/2  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) bL0+v@(r  
public SiteFileFetch(SiteInfoBean bean) throws IOException DMf^>{[  
{ d_5h6C z4  
siteInfoBean = bean; ~d{E>J77j  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); !\awT  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); t"0~2R6i  
if(tmpFile.exists ())  a$aI%  
{ KL5rF,DME  
bFirst = false; ~PlwPvWo  
read_nPos(); 5I&^n0h|&  
} DN^ln%#  
else ni%^w(J3Q  
{ ;"Ot\:0  
nStartPos = new long[bean.getNSplitter()]; cK-!Evv  
nEndPos = new long[bean.getNSplitter()]; zLxWyPM0;  
} ? erDP8  
2lp.Td`{  
^f`#8G7(  
Rdnd|  
} jC\R8_  
^<% w'*gR  
uxh4nyE  
public void run() =<e#  2  
{ DdSUB  
//获得文件长度 RhQOl9  
//分割文件 |LNXu  
//实例FileSplitterFetch l^Lg"m2  
//启动FileSplitterFetch线程 zG @!(  
//等待子线程返回 G&uj}rj  
try{ /`s^.Xh  
if(bFirst) P@5^`b|  
{ P?0b-Qr$a  
nFileLength = getFileSize();  )bK<t  
if(nFileLength == -1) 6]rrj  
{ o9~qJnB/O  
System.err.println("File Length is not known!"); h M8G"b  
} U-lN_?  
else if(nFileLength == -2) uq 6T|Zm  
{ yTDoS|B+)  
System.err.println("File is not access!"); U{O\  
} 4a3f!G$  
else /FYa{.Vlr  
{ qp{NRNkQ  
for(int i=0;i<nStartPos.length;i++) 1qQgAhoY  
{ hD$U8~zK  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); )(ma  
} 3BSeZ:j7  
for(int i=0;i<nEndPos.length-1;i++) s-C.+9  
{ p}Gk|Kjlq,  
nEndPos = nStartPos[i+1]; " 3^6  
} '[juPI(!  
nEndPos[nEndPos.length-1] = nFileLength; eq@ v2o7  
} a"EQldm|d  
} Eui;2P~  
71 A{"  
d&ZwVF!  
//启动子线程 4\$Ze0tv  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {(tE pr  
for(int i=0;i<nStartPos.length;i++) $PTedJ}*Y  
{ 7H[+iS0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )0GnTB;5Z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O]PfQ  
nStartPos,nEndPos,i); tlcA\+%)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }6S4yepl  
fileSplitterFetch.start(); >`NM?KP s  
} w"BTu-I  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 96PVn  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1L9^N  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 4p-$5Fk8}  
nEndPos = " + nFileLength); -p;o e}|  
// fileSplitterFetch[nPos.length-1].start(); X,q= JS  
pGcc6q1  
{jc~s~<#  
//等待子线程结束 We4 FR4`  
//int count = 0; vc!S{4bN  
//是否结束while循环 YT3QwN9  
boolean breakWhile = false; _Ng*K]0/E  
rxz3Mqg  
ad~ qr n\  
while(!bStop) GqAedz;.  
{ z`Q5J9_<cV  
write_nPos(); (dT!u8Oe  
Utility.sleep(500); lZua"Ju  
breakWhile = true; pIrAGA;  
*K98z ?  
CX:^]wY  
for(int i=0;i<nStartPos.length;i++) &t8_J3?Z  
{ $yc,D=*Isi  
if(!fileSplitterFetch.bDownOver) s<dD>SU  
{ iwVra"y  
breakWhile = false; 7]^ }  
break; FU[,,a0<<  
} GS$k  
} e7?W VV,  
if(breakWhile) U-? ^B*<  
break; g:6yvEu$ -  
E*I]v  
,C&>mv xA  
//count++; 2%<jYm#'z-  
//if(count>4) $ i&$ZdX  
// siteStop(); %zD-gw>  
} R] [M_ r  
q7]WR(e  
/j)VES  
System.err.println("文件下载结束!"); $`Xx5 Ts7  
} ?.A|Fy^  
catch(Exception e){e.printStackTrace ();} E 5t+;vL~  
} =5/;h+bk+3  
PVU"oz&T  
_Ry.Wth  
//获得文件长度 Z+dR(9otH3  
public long getFileSize() Fp6Y Y  
{ h]MVFn{  
int nFileLength = -1; G}-.xj]  
try{ L@_">' pR  
URL url = new URL(siteInfoBean.getSSiteURL()); ,1[??Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 9aU:[]w  
httpConnection.setRequestProperty("User-Agent","NetFox"); by U\I5  
],YYFU}  
N Sh.g #  
int responseCode=httpConnection.getResponseCode(); r^E]GDz  
if(responseCode>=400) q-G|@6O  
{ y9L#@   
processErrorCode(responseCode); ;F""}wzn  
return -2; //-2 represent access is error yUW&Wgc=:  
} 1 (i>Vt.+  
6XAr8mw9  
9xQ 8`7  
String sHeader; ij i.3-  
B -~&6D,  
)h0E$*  
for(int i=1;;i++) D i'u%r  
{ e^NEj1  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o$ce1LO?|N  
//Utility.log(in.readLine()); /plUzy2Yu  
sHeader=httpConnection.getHeaderFieldKey(i); &7w>K6p  
if(sHeader!=null) n+qVT4o  
{ b!X"2'  
if(sHeader.equals("Content-Length")) b_jZL'en  
{ FMd LkyK;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (Q5@MfK`  
break; UB$`;'|i  
} (bx\4Ws  
} ^dnz=FB  
else " q^#39i?  
break; [-t> G!)  
} .W :  
} 0O#B'Uu  
catch(IOException e){e.printStackTrace ();} N 2"3~  #  
catch(Exception e){e.printStackTrace ();} 2d2@J{  
nheU~jb  
P$3=i`X!nw  
Utility.log(nFileLength); h Y}/Y  
AM[jL'r|  
M7DLs;sD  
return nFileLength; 6%.  
} 4`6c28K0?  
c',:@2R  
|[ Ie.&)  
//保存下载信息(文件指针位置) lU $4NU wM  
private void write_nPos() 3kiE3*H  
{ Q)Iv_N/  
try{ ;T.s!B$Uu  
output = new DataOutputStream(new FileOutputStream(tmpFile)); aZj J]~bO  
output.writeInt(nStartPos.length); )Ig+uDGk  
for(int i=0;i<nStartPos.length;i++) b0YiQjS6>  
{ E69:bQ94u  
// output.writeLong(nPos); i Y*o;z,~  
output.writeLong(fileSplitterFetch.nStartPos); u  m: 0y,  
output.writeLong(fileSplitterFetch.nEndPos); GsIwY {d  
} KQ4kZN  
output.close(); *BLe3dok(  
} ({%oi h  
catch(IOException e){e.printStackTrace ();} %j'G.*TD  
catch(Exception e){e.printStackTrace ();} rGnI(m.  
} !%c{+]g  
RpO@pd m  
b4Z`y8=  
//读取保存的下载信息(文件指针位置) &yx NvyA[u  
private void read_nPos() v2hZq-q  
{ yo\N[h7  
try{ *Y85DEA  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); iHAU|`'N)  
int nCount = input.readInt(); gjj 93  
nStartPos = new long[nCount]; #NvQmz?J?  
nEndPos = new long[nCount];  hv+|s(  
for(int i=0;i<nStartPos.length;i++) Go>wo/Sb  
{ &5\^f?'b7  
nStartPos = input.readLong(); 6'xomRpYN  
nEndPos = input.readLong(); sl/=g   
} XE_ir Et  
input.close(); X E|B)Q(  
} *cbeyB{E  
catch(IOException e){e.printStackTrace ();} `|$'g^eCL  
catch(Exception e){e.printStackTrace ();} Y3-gUX*w0  
} ]N*L7AVl  
f UC9-?(K  
AXwaVLEBQ  
private void processErrorCode(int nErrorCode) lT8#bA  
{ & _; y.!  
System.err.println("Error Code : " + nErrorCode); *7ZGq(O  
} L7'%;?Z  
sI_7U^"[  
_7U]&Nh99  
//停止文件下载 dsJm>U)  
public void siteStop() TZ[Zm  
{ *G9sy_  
bStop = true; bEm7QgV{X  
for(int i=0;i<nStartPos.length;i++) s~*}0-lS  
fileSplitterFetch.splitterStop(); 0ZMJ(C  
/F.Wigv  
RK[D_SmS  
} !b8uLjd;  
} rQ/ ,XH  
//负责部分文件的抓取 $B;_Jo\|  
**FileSplitterFetch.java hoa7   
*/ OS-sk!  
package NetFox; #B8*gFZB  
1B|8ZmFJj  
Z$ p0&~   
import java.io.*; ,apNwkY  
import java.net.*; 8) N@qUV  
.N,&Uv-  
"- 31'R-  
public class FileSplitterFetch extends Thread { T.REq4<  
M|q~6oM  
#]CFA9 z  
String sURL; //File URL +Y}V3(w9X  
long nStartPos; //File Snippet Start Position ;}qhc l+  
long nEndPos; //File Snippet End Position `lO(s%HC  
int nThreadID; //Thread's ID =<c#owe:m  
boolean bDownOver = false; //Downing is over Xa," 'r  
boolean bStop = false; //Stop identical ~. YWV  
FileAccessI fileAccessI = null; //File Access interface Z:*@5  
#sTEQjJ,J  
 8"%RCE  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException CS 8jA\  
{ <[Q3rJ  
this.sURL = sURL; *)<B0SjT  
this.nStartPos = nStart; Kv37s0|g  
this.nEndPos = nEnd; g:7,~}_}^  
nThreadID = id; j~E",7Q'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 K<4Kk3  
} }lP;U$  
ljC(L/I  
eSEq{ ?>  
public void run() FdzNE  
{ n(1')?"mA  
while(nStartPos < nEndPos && !bStop) 08s_v=cF  
{ QzOkpewf  
mj&57D\fq  
0p(L'  
try{ ,HB2 hHD  
URL url = new URL(sURL); |l0Ea  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); b>\?yL/%+?  
httpConnection.setRequestProperty("User-Agent","NetFox"); >(r{7Qg  
String sProperty = "bytes="+nStartPos+"-"; sa1h%<   
httpConnection.setRequestProperty("RANGE",sProperty); {D`'0Z1"  
Utility.log(sProperty); )w h%|  
|&3x#1A  
P`$!@T0=  
InputStream input = httpConnection.getInputStream(); JhHWu<  
//logResponseHead(httpConnection); 7 <9yH:1  
lDc-W =X=  
6"/WZmOp  
byte[] b = new byte[1024]; $P z`$~  
int nRead; ,CvG 20>  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) <eN_1NTH_  
{ 'sh~,+g  
nStartPos += fileAccessI.write(b,0,nRead); o:S0*  
//if(nThreadID == 1) C NsNZJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m8R9{LC  
} JL=U,Mr6  
H 3@Z.D  
lg :  
Utility.log("Thread " + nThreadID + " is over!"); t?c}L7ht  
bDownOver = true; Rk6deI]  
//nPos = fileAccessI.write (b,0,nRead); ({s6eqMhDd  
} S4UM|`  
catch(Exception e){e.printStackTrace ();} t5B7I59  
} g{IF_ 1  
} NVKC'==0  
6%,C_7j  
d}'U?6 ob  
//打印回应的头信息 h `}}  
public void logResponseHead(HttpURLConnection con) *&BnF\?m  
{ V7d) S&*V  
for(int i=1;;i++) *NFg;<:j  
{ )s_n  
String header=con.getHeaderFieldKey(i); 7hP<f}xL  
if(header!=null) ({r*=wAP  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); #LlUxHv #  
Utility.log(header+" : "+con.getHeaderField(header)); 3_Cp%~Gi-_  
else !Ucjax~  
break; b[9&l|y^  
} /X"/ha!=&D  
} te|? )j  
d^03"t0O]  
N`@NiJ(O;  
public void splitterStop() :W#rhuzC  
{ +4;uF]T  
bStop = true; 5|3e&  
} M_v?9L  
j9Yb x#  
^G&3sF}  
} ^d}gpin  
}KUd7[s  
GSclK|#t E  
/* q6Rr.A  
**FileAccess.java ,.iRnR  
*//文件访问(定位,写) W1fW}0   
package NetFox; ~5Pb&+<$  
import java.io.*; 6E(Qx~i L  
Y8M]Lwj  
=4V&*go*\  
public class FileAccessI implements Serializable{ *B`Zq)  
:B3[:MpL}  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 j',W 64  
RandomAccessFile oSavedFile; k@zy  
long nPos; *eI)Z=8  
[Wd-Zn%  
]Chj T}  
public FileAccessI() throws IOException `&\Q +W  
{ theZ]5_C  
this("",0); ojYbR<jn9  
} 'z76 Sa  
sn7AR88M;  
f}g\D#`]/  
public FileAccessI(String sName,long nPos) throws IOException R_M?dEtE>  
{ ^` un'5Vk  
oSavedFile = new RandomAccessFile(sName,"rw"); S$KFf=0  
this.nPos = nPos; >U F  
oSavedFile.seek(nPos); f#+el y  
} EY*(Bw  
V5+SWXZ  
HhO".GA  
public synchronized int write(byte[] b,int nStart,int nLen) A-:O`RK  
{ 5F`;yh+e  
int n = -1; KiGp[eb  
try{ c/c$D;T  
oSavedFile.write(b,nStart,nLen); }Zl&]e  
n = nLen; 21k5I #U  
} NM ]bgpP  
catch(IOException e) d%l{V6  
{ ^u 3V E  
e.printStackTrace (); OL4z%mDZi  
} oIUy-|  
U(~+o  
&-(463  
return n; Gt9&)/#  
} IV\J3N^  
*~w[eH!!  
]HpA5q1ck  
} ~?B;!Csk  
'SQG>F Uy  
h iNEJ_f  
/* y:v,j42%  
**SiteInfoBean.java 9UvXC)R1  
*/ aF03a-qw<  
package NetFox; cuOvN"nuNj  
M Zmb`%BZ  
2^?:&1:  
public class SiteInfoBean { v4@Z(M  
 }fp-5  
cwGbSW$t  
private String sSiteURL; //Site's URL t&?i m<  
private String sFilePath; //Saved File's Path ^>"z@$|\:  
private String sFileName; //Saved File's Name qzb<J=FAU  
private int nSplitter; //Count of Splited Downloading File R8.CC1Ix  
K~ ;45Z2  
1S@vGq}  
public SiteInfoBean() JxyB(  
{//nSplitter的缺省值为5 %YOndIS:  
//default value of nSplitter is 5 T|tOTk  
this("","","",5); r|,i'T  
} )7_"wD` z  
GR\5WypoJ  
DY[$"8Kxcp  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) YM5fyv?  
{ y"Nsh>h  
sSiteURL= sURL; a# c6[!   
sFilePath = sPath; ^ns@O+Fk  
sFileName = sName; mrX^2SR  
this.nSplitter = nSpiltter; EbqcV\Kb  
ayAo^q  
j <o3JV  
} p !s}=wI `  
! !PYP'e  
znJ'iV f  
public String getSSiteURL() {d?$m*YR3`  
{ Qt|c1@J  
return sSiteURL; EUIIr4]  
} .!JVr"8  
4 B*0M  
&w=3^  
public void setSSiteURL(String value) xLx]_R()  
{ ([xo9FP;  
sSiteURL = value; p ;|jI1  
} < y*x]}  
m*mm\wN5  
|ae97 5  
public String getSFilePath() EM\'GW  
{ Q,80Hor#J  
return sFilePath; IgC}&  
} ^{8Gt @  
ZY:[ekm%4Z  
.Lfo)?zG  
public void setSFilePath(String value) Mg^e3D1_  
{ o=nsy]'&  
sFilePath = value; umdG(osR  
} T~b>B`_  
29reG,>  
Q[#vTB$f  
public String getSFileName() 7w3CXY  
{ s@fTj$h  
return sFileName; Ko^c|}mh*!  
} Vx @|O%  
<x!GE>sf+  
UUMtyf  
public void setSFileName(String value) >CkjUZu]&  
{ J!DF^fLe  
sFileName = value; IJ/sX_k  
} e${)w-R/e  
}W ^: cp  
~b:Rd{  
public int getNSplitter() )Z %T27r,^  
{ JAI)Eqqv]  
return nSplitter;  aH#l9kCb  
} bMU(?hb  
Rar"B*b;$  
7==f\%,  
public void setNSplitter(int nCount) N~F RM& x  
{ Zk[&IBE_  
nSplitter = nCount; ;>mCalwj  
} 2}W0 F2*  
} 8#Q$zLK42N  
r#6_]ep}<'  
2ZQ}7`Y  
/* C{d7J'Avk  
**Utility.java u!:z.RH8n  
*/ Reu*Pe  
package NetFox; owPm/F  
z.}[m,oTF  
vp.ZK[/`  
public class Utility { +Y+Y6Ac[}  
){Ob,LEU&  
"kc/J*u-3  
public Utility() M|] "W  
{ Ka`=WeJ|  
Yf[Qtmh]I  
M5x U9]B  
} [{X^c.8G)  
5pn)yk~  
//线程睡眠 @'=Uq  
public static void sleep(int nSecond) }Nb8}(6  
{ 72,rFYvpK  
try{ EKp@9\XBC  
Thread.sleep(nSecond); \.g\Zib )  
} 4WB-Ec  
catch(Exception e) AdWq Q  
{ $k$4% 7  
e.printStackTrace (); 6eokCc"o  
} 5K?}}Frrt`  
} 5#QXR+ T  
4npqJ1  
//日志 V"!G2&  
public static void log(String sMsg) Y{*u&^0{  
{ r `eU~7  
System.err.println(sMsg); l (3bW1{n  
} Xj*vh m%i  
U!m @DJj  
n k2om$nN  
public static void log(int sMsg) q5 L51KP2  
{ vaon{2/I  
System.err.println(sMsg); W}|'#nR  
} <?D\+khlq  
} @ps1Dr4s  
1 tR_8lC  
C^ )*Dsp  
/* (os$B  
**TestMethod.java zuJtpMn  
*/ YA&g$!  
package NetFox; > 0<)=  
CZbYAxNl  
:EHJ\+kejX  
public class TestMethod { ;Q+xK h%  
y?SyInt  
nQ GQWg`  
public TestMethod() FV,4pi  
{ ///xx/weblogic60b2_win.exe ,y%3mR_~  
try{ 4l&g6YneX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); /W<>G7%.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); d`1I".y  
SiteFileFetch fileFetch = new SiteFileFetch(bean); =LTmr1?  
fileFetch.start(); *kIc9}  
} =f(cH152T  
catch(Exception e){e.printStackTrace ();} ,<:!NF9  
3R&lqxhg  
_`#3f1F@[  
} 1xc~`~  
yObuWDA9  
al`3Lu0  
public static void main(String[] args) kapC%/6"  
{ 2c/Ys4/H4]  
new TestMethod(); 4ikdM/  
} "YB** Y  
} ?3O9eZY@  
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