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http断点续传简单实现(java)

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/* 1 DqX:WM6  
**SiteFileFetch.java h48YDWwy  
*/ ET.dI.R8  
package NetFox; hCAZ{+`z  
import java.io.*; KzNm^^#/$A  
import java.net.*; { D+Ym%n  
P_&p=${  
nM8[  
public class SiteFileFetch extends Thread { *GJ:+U&m[  
b!^@PIX  
|NJ}F@t/5  
SiteInfoBean siteInfoBean = null; //文件信息Bean vQgq]mA?  
long[] nStartPos; //开始位置 BZ+;n |<r  
long[] nEndPos; //结束位置 6WeM rWx  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 !p',Za   
long nFileLength; //文件长度 7 \X$7  
boolean bFirst = true; //是否第一次取文件 {~_ Y _-  
boolean bStop = false; //停止标志 Bd&`Xfebj  
File tmpFile; //文件下载的临时信息 VO_dA4C}z  
DataOutputStream output; //输出到文件的输出流 FqZgdmwR  
M?$ZJ-  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) oxzq!U  
public SiteFileFetch(SiteInfoBean bean) throws IOException /P:EWUf'  
{ 2)9r'ai?a  
siteInfoBean = bean; oQ\&}@(V  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); G>K@AW #  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); )c+k_;t'+  
if(tmpFile.exists ()) DW>ES/B8$(  
{ [EOVw%R  
bFirst = false; @PX\{6&  
read_nPos(); 2"X~ju  
} id?E)Jy  
else OhFW*v  
{ <*wM=aq  
nStartPos = new long[bean.getNSplitter()]; 8{ gXToK  
nEndPos = new long[bean.getNSplitter()]; psUE!~9,  
} nZ E)_  
+D`*\d1  
MA* :<l  
R/~,i;d>  
} 0%#\w*X8  
G\kpUdj}  
J+ts  
public void run() TH:W#Ot  
{ 59lj7  
//获得文件长度 sJU`u'w  
//分割文件 qybxXK:  
//实例FileSplitterFetch ^2C>L}  
//启动FileSplitterFetch线程 /iG7MC\`  
//等待子线程返回 p!DP`Ouc3\  
try{ =wrP:wYF  
if(bFirst) RB$ z]/=  
{ [Y8S[YY  
nFileLength = getFileSize(); snC/H G7  
if(nFileLength == -1)  prrT:Y  
{ nB] Ia?  
System.err.println("File Length is not known!"); s`;f2B/|  
} +~35G:&:  
else if(nFileLength == -2) jatr/  
{ 5k$vlC#[H  
System.err.println("File is not access!"); HdNnUDb$B  
} !0" nx{7.  
else N'?u1P4G  
{ bK*~ol  
for(int i=0;i<nStartPos.length;i++) ^RNOcM|  
{ S|AjL Ng#  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); O|'1B>X  
} L l}yJ#3,  
for(int i=0;i<nEndPos.length-1;i++) K 1W].(-@4  
{ !20X sO  
nEndPos = nStartPos[i+1]; Bp_wnd  
} ?obm7<  
nEndPos[nEndPos.length-1] = nFileLength; G5Ykbw#  
} bRsTBp;R`I  
} tj5giQ3DG)  
z7T0u.4Ss  
tC)6  
//启动子线程 L0"~[zB]N  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ~x]9SXD%  
for(int i=0;i<nStartPos.length;i++) Dl,`\b@Fw3  
{ 2*1ft>Uty  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7x k|+!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /+[63=fl  
nStartPos,nEndPos,i); 1@qgF  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ."6[:MF  
fileSplitterFetch.start(); lr3mE  
} d%ME@6K)  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Hj6'pJ4  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ue{xnjw>U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,={t8lN  
nEndPos = " + nFileLength); X.V[0$.;  
// fileSplitterFetch[nPos.length-1].start(); L:R<e#kgS  
\#Up|u:  
DL8x":;  
//等待子线程结束 @S3f:s0~D  
//int count = 0; Yj3I5RG  
//是否结束while循环 XKU=oI0\j  
boolean breakWhile = false; <<zI\+V  
!mnUdR|>(  
vhgLcrn  
while(!bStop) {C3Y7<  
{ 3yO=S0`  
write_nPos(); 'i|rj W(  
Utility.sleep(500); eV};9VJ$F  
breakWhile = true; .*5Z"Q['G  
~Xv=9@,h  
`dW]4>`O  
for(int i=0;i<nStartPos.length;i++) w0J|u'H  
{ \".^K5Pm  
if(!fileSplitterFetch.bDownOver) D4u% 6R|F  
{ Q[u6|jRt  
breakWhile = false; wkb$^mU  
break; A9:NKY{z  
} uGVy6,  
} Da1aI]{I  
if(breakWhile) I'!/[\_  
break; *?% k#S  
egR-w[{  
QlZ@ To  
//count++; ^ c%N/V \  
//if(count>4) T.:+3:8|F  
// siteStop(); B80aw>M  
} e %O0hE  
k$i'v:c|:i  
=o7}]k7  
System.err.println("文件下载结束!"); md Gwh7/3  
} zsQoU&D 5  
catch(Exception e){e.printStackTrace ();} l*=aMjd?  
} EqB)sK/3  
N{Qxq>6 G  
,xsH|xW  
//获得文件长度 nE W31 8  
public long getFileSize() sRhKlUJG  
{ *_-'/i  
int nFileLength = -1; j`>^1Q  
try{ !CY&{LEYn0  
URL url = new URL(siteInfoBean.getSSiteURL()); [iS$JG-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iCQ>@P]nE  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7jG(<!,  
XNH4vG |  
19U]2D/z  
int responseCode=httpConnection.getResponseCode(); !{%:qQiA  
if(responseCode>=400) _^ |2}t  
{ dJk9@u  
processErrorCode(responseCode); ,!QV>=  
return -2; //-2 represent access is error ;0%OB*lcgE  
}  iThSt72  
83Ou9E!W  
zGo|JF  
String sHeader; K\?]$dK5  
K7)kS  
k;^ :  
for(int i=1;;i++) uE5X~  
{ e":G*2a  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); vGd1w%J-  
//Utility.log(in.readLine()); &, a3@i  
sHeader=httpConnection.getHeaderFieldKey(i); Fke//- R  
if(sHeader!=null) o>]`ac0b}Y  
{ C(?blv-vM0  
if(sHeader.equals("Content-Length")) bn9;7`>.  
{ zw@'vncc  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); o^p  
break; M[]A2'fS  
} L:&k(YOBA  
} E8[T   
else v3[@1FQ"  
break; TLa]O1=Bf.  
} o*S"KX $  
} X[$++p .  
catch(IOException e){e.printStackTrace ();} t#E}NR  
catch(Exception e){e.printStackTrace ();} eVh - _  
Sus;(3EX  
QO;4}rq  
Utility.log(nFileLength); % ZU/x d  
0#p/A^\#7M  
e]8,:Gd(  
return nFileLength; Am4lEvb  
} 6sfwlT  
oYM3Rgxf9Q  
hVpCB,  
//保存下载信息(文件指针位置) TD@v9  
private void write_nPos() :$3oFN*g  
{ WgQBGch,!  
try{ rS XzBi{  
output = new DataOutputStream(new FileOutputStream(tmpFile)); (8a#\Y[b  
output.writeInt(nStartPos.length); pbXi9|bI  
for(int i=0;i<nStartPos.length;i++) aptY6lGv-|  
{ tOl e>]  
// output.writeLong(nPos); K95;rd  
output.writeLong(fileSplitterFetch.nStartPos); %3Z/+uT@v]  
output.writeLong(fileSplitterFetch.nEndPos); kSncZ0K{  
} j Ch=@<9  
output.close(); Q4]4@96Aj  
} kLSrj\6I[  
catch(IOException e){e.printStackTrace ();} ?)4?V\$  
catch(Exception e){e.printStackTrace ();} y(jg#7)  
} E+95WF|4k"  
cQN sL  
]2SI!Ai7  
//读取保存的下载信息(文件指针位置) /B3R1kNf|  
private void read_nPos() ^C)n$L>C0  
{ '-$XX%TOAc  
try{ Rqip kx  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); tfO#vw,@  
int nCount = input.readInt(); q>!L6h5]t  
nStartPos = new long[nCount]; i^`9syD  
nEndPos = new long[nCount]; 256LHY|6  
for(int i=0;i<nStartPos.length;i++) ~l[r a  
{ 3INI?y}t   
nStartPos = input.readLong(); mB'3N;~  
nEndPos = input.readLong(); jdA ]2]  
} v-j3bB  
input.close(); OW;tT=ql  
} $^/0<i$   
catch(IOException e){e.printStackTrace ();} <i\A_qqc/  
catch(Exception e){e.printStackTrace ();} C@\{ehG  
} knp>m,w  
S^I,Iz+`S'  
>H][.@LyR  
private void processErrorCode(int nErrorCode) QbFHfA2Ij  
{ q<vf,D@{ !  
System.err.println("Error Code : " + nErrorCode); I&yVx8aH}  
} Wzq>JNn y  
c~}l8M %  
Tb;d.^  
//停止文件下载 M)-6T{[IT  
public void siteStop() \ gwXH  
{ J97R0  
bStop = true; koG{ |elgB  
for(int i=0;i<nStartPos.length;i++) ]$-cMX  
fileSplitterFetch.splitterStop(); 8TV;Rtl  
b,H[I!. %  
TA18 gq  
} LwqC ~N  
} -;(Q1)&  
//负责部分文件的抓取 =HDI \LD<  
**FileSplitterFetch.java q Dd~2"er  
*/ }Nj97 R  
package NetFox; j1$8#/r;c  
RF}X ER  
j-@kW'K  
import java.io.*; @r^!{  
import java.net.*; q}|U4MJm  
M+>`sj  
 %V G/  
public class FileSplitterFetch extends Thread { b]Kk2S/  
6(&Y(/  
.\Fss(Zn  
String sURL; //File URL U%B(5cC  
long nStartPos; //File Snippet Start Position b}!3;:iD  
long nEndPos; //File Snippet End Position AbwbAm+  
int nThreadID; //Thread's ID  }alj[)  
boolean bDownOver = false; //Downing is over <~emx'F|  
boolean bStop = false; //Stop identical }3 m0AQ;K  
FileAccessI fileAccessI = null; //File Access interface [onqNp  
BbOu/i|  
or*HC&c7  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException =v~1qWX  
{ AnsjmR:Jv  
this.sURL = sURL; _;9!  
this.nStartPos = nStart; Xt/Ksw"wn  
this.nEndPos = nEnd; 8kL4~(hY  
nThreadID = id; R,2=&+ e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 D>L2o88  
} K<sC F[  
WKM)*@#,  
"@3@/I  
public void run() 8ovM\9qT  
{ 4R%*Z ~  
while(nStartPos < nEndPos && !bStop) .\3`2  
{ 'm=*u SJK  
H!IshZfktn  
7k%T<;V  
try{ 5A Bhj*7  
URL url = new URL(sURL); fIC9WbiH-  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P'Q$d+F,  
httpConnection.setRequestProperty("User-Agent","NetFox"); SkNre$>t{  
String sProperty = "bytes="+nStartPos+"-"; j=+"Qz/hr_  
httpConnection.setRequestProperty("RANGE",sProperty); ^H'a4G3  
Utility.log(sProperty); 4NR@u\S  
/?-7Fg+,  
i8X`HbmN  
InputStream input = httpConnection.getInputStream(); ;Q0bT`/X  
//logResponseHead(httpConnection); =1;=  
9W`Frx'h1  
NmIHYN3  
byte[] b = new byte[1024]; B6P|Z%E;D6  
int nRead; V}w;Y?] J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a T  l c  
{ x<i}_@Sn_+  
nStartPos += fileAccessI.write(b,0,nRead); R>@uY( >dJ  
//if(nThreadID == 1) t=euE{c  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *!e(A ]&  
} `\| ssC8u  
NF$\^WvYSP  
d5I f"8`@  
Utility.log("Thread " + nThreadID + " is over!"); &xZyM@  
bDownOver = true; '(&%O8Yi  
//nPos = fileAccessI.write (b,0,nRead); JWP*>\P  
} V:NI4dv/R  
catch(Exception e){e.printStackTrace ();} =ziwxIo6  
} -ZOBAG*  
} C&\5'[*  
cp Ear  
,38Eq`5&W  
//打印回应的头信息 Ok-.}q>\Mv  
public void logResponseHead(HttpURLConnection con) *~$~yM/~3U  
{ #1-xw~_  
for(int i=1;;i++) ~q +[<xR\  
{ =TvzS%U  
String header=con.getHeaderFieldKey(i); 0"k |H&  
if(header!=null) @MR?6n*k  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Mq%,lJA\  
Utility.log(header+" : "+con.getHeaderField(header)); <msxHw  
else RH;:9_*F  
break; _#$9 y1bd  
} bucR">_p  
} 7Ob*Yv=[  
_+f+`]iM  
D]! aT+  
public void splitterStop() %Tn#-  
{ N^?9ZO   
bStop = true; v]:=K-1n  
} *y[PNqyd  
1m<RwI3s  
R614#yn-+  
} |w}w.%  
:HViX:]H  
#:fQ.WWO  
/* 1MkI0OZE  
**FileAccess.java ^W83ByP  
*//文件访问(定位,写) G1T^a>tj4  
package NetFox; Q'apG)0I  
import java.io.*; )w~Fo,   
8U2dcx:G3  
(3vHY`9  
public class FileAccessI implements Serializable{ T>>YNaUL  
92W&x'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 aiCFH_H4;L  
RandomAccessFile oSavedFile; -l+P8:fL~  
long nPos; w&&2H8  
JYqSL)Ta*t  
[jx0-3s:X  
public FileAccessI() throws IOException lEL78l.  
{ Tq<2`*Qs  
this("",0); ihL/n  
} 0 5\dl  
>gtQw!  
$*[{J+t_  
public FileAccessI(String sName,long nPos) throws IOException dBC bL.!  
{ |BMV.Zi  
oSavedFile = new RandomAccessFile(sName,"rw"); @# P0M--X  
this.nPos = nPos; R_P}~l  
oSavedFile.seek(nPos); &Jc_Fc(M  
} -XoPia2  
pI`?(5iK6|  
~.Ik#At  
public synchronized int write(byte[] b,int nStart,int nLen) <M?:  
{ |Q~cX!;  
int n = -1; S|AM9*k9  
try{ "pxzntY|  
oSavedFile.write(b,nStart,nLen); &YP#M |  
n = nLen; USJ- e  
} H2gj=krK  
catch(IOException e) QA!_} N4n  
{ s,VXc/  
e.printStackTrace (); |8_JY2 R  
} UQ Co}vM  
k?nQ?B W  
w-B^ [<  
return n; ^yviV Y  
} 10Wz,vW,n  
]T! }XXK  
#1'\.v  
} {X]R-1>  
9V uq,dv  
pC,o2~%{  
/* 3{% LS"c  
**SiteInfoBean.java 59uwB('|lH  
*/ gB,G.QM*6  
package NetFox; S&nxok`e^  
ewNz%_2  
:!&;p  
public class SiteInfoBean { qMBR *f  
zZ-wG  
;.s l*q1A  
private String sSiteURL; //Site's URL t,)N('m}=  
private String sFilePath; //Saved File's Path VvbFp  
private String sFileName; //Saved File's Name MWk:sBCqr  
private int nSplitter; //Count of Splited Downloading File ;#GoGb4AM  
jd`},X/  
tL SN`6[:  
public SiteInfoBean() $Kj&)&M  
{//nSplitter的缺省值为5 %b.UPS@I  
//default value of nSplitter is 5  q}Z3?W  
this("","","",5); T70QJ=,  
} 23(=Xp3;>  
73A)lU.  
iJFs0?*  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .ujT!{>v/  
{ yj6@7@l>A  
sSiteURL= sURL; rI$`9d  
sFilePath = sPath; `pZs T ^G[  
sFileName = sName; ^62|d  
this.nSplitter = nSpiltter; Rr(* aC2P  
j Ib  
~\nBjM2  
} ;32#t[i b  
C) QKPT  
EY`H}S!xy  
public String getSSiteURL() g_*T?;!.U  
{ 8?t"C_>*e  
return sSiteURL; egR9AEJvz  
} O[17";P  
s}&bJ"!Z  
RIM`omM  
public void setSSiteURL(String value) "yz iXT@V  
{ Thy=yz;p  
sSiteURL = value; $DFv30 f  
} QlFZO4 P3|  
+YOKA*  
qJ!Z~-hS  
public String getSFilePath() 39U5jj7i  
{ +eQe%U  
return sFilePath; Mkp/0|Q*  
} k?BJdg)xJ  
qVjWV$j  
5lKJll^2:  
public void setSFilePath(String value) %ugHhS!  
{ MJ<Jb,D1  
sFilePath = value; ~pk(L[G  
} HWns.[  
V=I"-k}RL  
&WXY'A=  
public String getSFileName() E9j+o y  
{ T&Xl'=/  
return sFileName; >>l`,+y  
}  uD_v!  
4Ph0:^i_  
vP%tk s+.  
public void setSFileName(String value) ~ jU/<~s  
{ \u-0v.+|  
sFileName = value; Mj>}zbpk /  
} js^ ,(CS  
~Vh(6q.oT  
.Hhhi  
public int getNSplitter() pN6%&@) =  
{ C<^YVeG  
return nSplitter; D\~zS`}  
} -kz4FS  
{>3\ N0e5  
|s7`F%  
public void setNSplitter(int nCount) )'4P.>!!aQ  
{ rsn.4P=  
nSplitter = nCount; (w (  
} {n3EGSP#  
} uy_wp^  
cxeghy:;U  
3:/'t{ ^B  
/* xVB;s.'!  
**Utility.java {3a&1'a0g  
*/ XKL3RMF9r  
package NetFox; 3gWvmep1  
aIy*pmpD=  
U=Y)V%  
public class Utility { 1[F3 Z  
sRVIH A ,  
C-eA8pYY/  
public Utility() -Ue$T{;RoH  
{ \mM<\-'p  
|rw%FM{F  
0X8t>#uF  
} !{et8F@d|  
Xm2\0=v5;  
//线程睡眠 j!~l,::$"X  
public static void sleep(int nSecond) Kyt)2p  
{ 'XQ`g CF=  
try{ <oKGD50#  
Thread.sleep(nSecond); l} ^3fQXI  
} Kemw^48ts  
catch(Exception e) GY3 Wj  
{ ;rI@ *An  
e.printStackTrace (); zQ?!f#f  
} 'mCe=Y  
} 2=0DCF;Bv  
A,-6|&F  
//日志 ;a=w5,h:  
public static void log(String sMsg) 5 S Xn?  
{ _!;Me )C  
System.err.println(sMsg); 1Q;}z Hd  
} 0<"k8 k@J  
<tpmUA[]  
'crlA~&#/  
public static void log(int sMsg) c5q9 LQ/  
{ "]'?a$\ky:  
System.err.println(sMsg); yw[#  
} !?f5>Bl  
} _EnwME {@  
C$Lu]pIL*  
r0t^g9K0  
/* pA.J@,>`}  
**TestMethod.java 3uU]kD^  
*/ uJx"W  
package NetFox; 8 a!Rb-Q:  
,jA)wJ  
R2etB*k6[  
public class TestMethod { k 4/D8(OXw  
j.~!dh$mg  
(Q[fS:U  
public TestMethod() 76tdJ!4Z  
{ ///xx/weblogic60b2_win.exe \y6OUM2y  
try{ /[:dp<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ZN"j%E{d  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); LZPuDf~/  
SiteFileFetch fileFetch = new SiteFileFetch(bean); f-6vLX\Vu  
fileFetch.start(); J]W5[)L  
} <9ig?{'  
catch(Exception e){e.printStackTrace ();} CO-_ea U(  
U~{du;\  
sAo& uZ  
} W)'*m-I  
MUOa@O,  
bQe^Px5 !.  
public static void main(String[] args) 1}hIW":3Sr  
{ *vgl*k?)  
new TestMethod(); s &Dg8$  
} NC&DFJo  
} A,i75kd  
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