http断点续传简单实现（java)

/* 1}'|HAu  
**SiteFileFetch.java @c5TSHSL.  
*/ LA1UD+S  
package NetFox; ^f@EDG8  
import java.io.*; ^'#vUj:"  
import java.net.*; @dw0oRF  
'b%S3)}  
h\jwXMi,tj  
public class SiteFileFetch extends Thread { d?'q(6&H  
y_QK _R<f  

3^C  
SiteInfoBean siteInfoBean = null; //文件信息Bean 2b2/jzO}J  
long[] nStartPos; //开始位置 0*x  
long[] nEndPos; //结束位置 3PPN_Z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 g&&5F>mF  
long nFileLength; //文件长度 NKh8'=S  
boolean bFirst = true; //是否第一次取文件 U@DIO/C,m`  
boolean bStop = false; //停止标志 U }xRvNz  
File tmpFile; //文件下载的临时信息
I)T]}et  
DataOutputStream output; //输出到文件的输出流 Ub0g{   
iku) otUc  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） aO6w:IO  
public SiteFileFetch(SiteInfoBean bean) throws IOException RP!X5  
{ %i$]S`A}  
siteInfoBean = bean; 'f]\@&Np  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); BlMc<k  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); k\I+T~~xD  
if(tmpFile.exists ()) n YWS'i@  
{ ]|'Mf;  
bFirst = false; r+ k5Bk'  
read_nPos(); i#=s_v8  
} O6 bB CF;  
else %,1bh  
{ N"@aisi)  
nStartPos = new long[bean.getNSplitter()]; yMB*/vs  
nEndPos = new long[bean.getNSplitter()]; xXQDHc-Ba  
} kg1z"EE  
@.@O#  
[ lW~v:W  
$QN}2lJ>  
} #[ipJ %  
G?v]p~6  
>+LFu?y  
public void run() ,p {|f}0  
{ 9/'zk
  
//获得文件长度 09HlL=0q  
//分割文件 AQ7w5}g+V  
//实例FileSplitterFetch %dw@;IZ#8{  
//启动FileSplitterFetch线程 f+d
[Q1  
//等待子线程返回 }\?UmuolQ  
try{ EPkmBru ^  
if(bFirst) 3]$qY_|7  
{ .0}]/%al  
nFileLength = getFileSize(); tUaDwIu#  
if(nFileLength == -1) PS7ta?V QC  
{ XmJu{RbS  
System.err.println("File Length is not known!"); <xv@us7  
} ;Hk{bz
(  
else if(nFileLength == -2) Y|stxeOC  
{ kLtm_  
System.err.println("File is not access!"); 3\JEp,5  
} Xt& rYv  
else [Wf%iwB  
{ .?|pv}V  
for(int i=0;i<nStartPos.length;i++) ^M
_0M  
{ A0~uv4MC  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); g]%sX6T  
} .EpcMXT%  
for(int i=0;i<nEndPos.length-1;i++) cdY|z]B  
{ >PHin%#  
nEndPos = nStartPos[i+1]; z3>ldT  
} 7|bzopLJk  
nEndPos[nEndPos.length-1] = nFileLength; "&lQ5]N.%  
} ]6#bp,  
} HtFc+%=  
i-Er|u; W  
}RvinF:5  
//启动子线程 D;
nm~O%  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Okxuhzn>"  
for(int i=0;i<nStartPos.length;i++) F5s Pd  
{ v!~tX*q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), AYb-
BaIc  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ~?E.U,R  
nStartPos,nEndPos,i); Q#M@!&  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Pr|BhX  
fileSplitterFetch.start(); ,E ]vM&  
} O1xK\ogv  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ww\M3Q`h  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *5T^wZpj)  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", H;D5)eJ90  
nEndPos = " + nFileLength); N=%4V  
// fileSplitterFetch[nPos.length-1].start(); x)GpNkx:  
xw2dNJL  

CvkZ<i){  
//等待子线程结束 
b%A+k"d  
//int count = 0; 0KT^V R  
//是否结束while循环 meJ%mY  
boolean breakWhile = false; Pnl+.?  
xs?Ska,N  
Qze.1h  
while(!bStop) 3&`LVhx  
{ fD:BKJQ  
write_nPos(); -?%81 z.Qq  
Utility.sleep(500); d0U-:S-  
breakWhile = true; Tew?e&eO  
r8%"#<]/  
#X 1 GL  
for(int i=0;i<nStartPos.length;i++) }aSTo"~m#  
{
mZ_643|  
if(!fileSplitterFetch.bDownOver) o|`%>&jP  
{ {wJ8% ;Z7  
breakWhile = false; +PAb+E|,  
break; {#U3A_y  
} W!jg  
} t nvCtuaR  
if(breakWhile) e)BU6m%  
break; $@utlIXA'  
6>DmcG:.  
xky +"  
//count++; Mj!g1Q  
//if(count>4) RwyX,|  
// siteStop(); ^L?2y/  
} Lqa|9|!  
&dsXK~9M>  
xw
Si.~.  
System.err.println("文件下载结束！"); oU`{6 ~;  
} |&u4Q /0  
catch(Exception e){e.printStackTrace ();} dQljG.PiK  
} 15J t @{<r  
vCX
54  
X:2)C-l?  
//获得文件长度 BWF>;*Xro  
public long getFileSize() !FA[ ]d4  
{ u;G-46  
int nFileLength = -1; T;C0t9Yew  
try{ 'f_[(o+n  
URL url = new URL(siteInfoBean.getSSiteURL()); nG4}8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,II-:&H  
httpConnection.setRequestProperty("User-Agent","NetFox"); *G&3NSM-  
i K,^|Q8  
]iezwz`'  
int responseCode=httpConnection.getResponseCode(); r7FFZNs!  
if(responseCode>=400) \DMZ 
M  
{ c9O0YQ3&8  
processErrorCode(responseCode); _=YHO.  
return -2; //-2 represent access is error 2'U+QK@  
} wGLSei-s  
CbW>yr  
Xte"tf9(C  
String sHeader; }'u0Q6Obj  
wNm1H[{  
b=PB"-  
for(int i=1;;i++) 1ir~WFP  
{ p N+1/m,  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); B%(-UTQf  
//Utility.log(in.readLine()); | Kw}S/F  
sHeader=httpConnection.getHeaderFieldKey(i); rO[ Zx'a  
if(sHeader!=null)
Uys[0n  
{ ~5:-;ZbZ  
if(sHeader.equals("Content-Length")) 0zc~!r~  
{ <wTD}.n  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 0#:St  
break; \f4JIsZ-&  
} 68QA%m'J  
} 6Eu"T9(  
else \5DOp-2  
break; R>B4v+b  
} K<E|29t^k  
} *pSD[E>SU  
catch(IOException e){e.printStackTrace ();} AQgagE^  
catch(Exception e){e.printStackTrace ();} ydMfV-  
Nhrh>x[wJ  
D` abVf  
Utility.log(nFileLength); ,V`[;~49  
I*4g ;1x  
fI }v}L^  
return nFileLength; B&Iy_;  
} k)TNmpL%"  
,M0#?j>  
9{&oVt~Y$  
//保存下载信息（文件指针位置） `nv82v  
private void write_nPos() 4l?"zv1  
{ /SKgN{tWe  
try{ 3:MAdh[w  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -p*j9 z  
output.writeInt(nStartPos.length); N VB
WF  
for(int i=0;i<nStartPos.length;i++) d9pZ
g=$8  
{ i1^#TC$x  
// output.writeLong(nPos); QLD
ld[  
output.writeLong(fileSplitterFetch.nStartPos); C^fUhLVSZ^  
output.writeLong(fileSplitterFetch.nEndPos); u(C?\HaH  
} u&Cu"-%=M  
output.close(); L4!T  
} \9%RY]TK3  
catch(IOException e){e.printStackTrace ();} js F96X{  
catch(Exception e){e.printStackTrace ();} &XZS}n  
} `3'4_@7s9  
Bs;.oK5!n@  
~L?q.*q  
//读取保存的下载信息（文件指针位置） !9g>/9h  
private void read_nPos() zrE Dld9  
{ hM[QR'\QS  
try{ $;As7MI  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 9
#)&  
int nCount = input.readInt(); 7thB1cOJ  
nStartPos = new long[nCount]; 2[~|6@n  
nEndPos = new long[nCount]; \{{i:&] H  
for(int i=0;i<nStartPos.length;i++) R}0xWPt9G  
{ ;Y%.m3  
nStartPos = input.readLong(); tWa_-Un3  
nEndPos = input.readLong(); <?Y.w1  
} xa?   
input.close(); 0=I:VGC3  
} ?X~U[dV?  
catch(IOException e){e.printStackTrace ();} ~O~R,h>  
catch(Exception e){e.printStackTrace ();} U( (F<  
} Wer.VL  
;H`>jI$  
BiI`oCX  
private void processErrorCode(int nErrorCode) {N`<THPP  
{ c5AEn -Q  
System.err.println("Error Code : " + nErrorCode); L%5g]=  
} }1? 2  
/5r!Fhx  
.!yw@kg  
//停止文件下载 7!jbID~  
public void siteStop() <j&LC /]o  
{ U`)o$4Bq  
bStop = true; RJ~I?{yR0[  
for(int i=0;i<nStartPos.length;i++) ]x^v;r~  
fileSplitterFetch.splitterStop(); MClvmv^  
,Vr'F  
'J(B{B7|  
} <p\iB'y  
} PNG!q}(c  
//负责部分文件的抓取 L0EF CQ7  
**FileSplitterFetch.java 5|Hz$oU  
*/ rFU|oDF  
package NetFox; Ika(ip#]=  
!F[^?:pK  
f,WAl\  
import java.io.*; Oq4J$/%  
import java.net.*; K-,8~8[  
IHStN,QD  
\iM  
public class FileSplitterFetch extends Thread { q&0I7OV  
6U[bAp  
<ecif_a=m  
String sURL; //File URL m j@{hGP  
long nStartPos; //File Snippet Start Position 1jkMje  
long nEndPos; //File Snippet End Position 0PT\/imgN  
int nThreadID; //Thread's ID _'"$,~ZWY  
boolean bDownOver = false; //Downing is over tp?< e  
boolean bStop = false; //Stop identical ;nZN}&m   
FileAccessI fileAccessI = null; //File Access interface q8[I` V{  
(vb8Mk
  
=x^b  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException VtzX I2.2  
{ 4pC.mRu 0  
this.sURL = sURL; sJB::6+1(|  
this.nStartPos = nStart; >uVr;,=y  
this.nEndPos = nEnd; 1Aw/-FxJ  
nThreadID = id; TYN~c(  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 jw$[b=sa  
} \&.]!!Q  
1k?k{Ri  
tC4 7P[b  
public void run() a@}A;y'd  
{ a[A9(Ftn  
while(nStartPos < nEndPos && !bStop) Y=YIz>u  
{ -9> oB  
8}<4f|?  
{v~.zRW%]r  
try{ ! C|VX,w  
URL url = new URL(sURL); 1GI/gc\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7qT>wCVT  
httpConnection.setRequestProperty("User-Agent","NetFox"); fsH=2p  
String sProperty = "bytes="+nStartPos+"-"; z-;2)RkV2  
httpConnection.setRequestProperty("RANGE",sProperty); c]!Yb-  
Utility.log(sProperty); <yz&> +9,  
+c-?1j  
B?p18u$i#l  
InputStream input = httpConnection.getInputStream(); OjRJyhzS*  
//logResponseHead(httpConnection); WC *e#QP  
/`vn/X^?^  
J8:f9a:|M  
byte[] b = new byte[1024]; xIb^x=|h  
int nRead; zf}X%tp  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W&Pp5KR  
{ ,sln0  
nStartPos += fileAccessI.write(b,0,nRead); <Zn-P  
//if(nThreadID == 1) Qkq9
oZ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .uwD;j +#  
} 2c4x=%  
Q{"QpVY8  
sm>5n_Vw  
Utility.log("Thread " + nThreadID + " is over!"); i1k#WgvZR  
bDownOver = true; [mJmT->  
//nPos = fileAccessI.write (b,0,nRead); FEzjP$  
} ubZcpqm?Q  
catch(Exception e){e.printStackTrace ();} /2#1Oi)
o  
} *D6X&Hg&5  
} rj> _L  
8O_0x)X  
K>x+*UPL  
//打印回应的头信息 h(1o!$EU2  
public void logResponseHead(HttpURLConnection con) v(vJ[_&%  
{ Od5I:p]N  
for(int i=1;;i++) /n&Y6@W  
{ % XS2;V  
String header=con.getHeaderFieldKey(i); !&b wFO>P  
if(header!=null) .,$<waGD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ]|PDsb"e  
Utility.log(header+" : "+con.getHeaderField(header)); 1?j['~aE  
else @x@*=  
break; Fo@cz"%  
}  a }m>  
} n%Df6zQ<@s  
l6O8:XI  
Vim*4^[#L  
public void splitterStop() @#CZ7~Hn  
{ y_e$W3bON,  
bStop = true; "-HmXw1+t  
} (;.wsz&K  
BJ,9C.|  
-=)Al^V4T  
} XwNJHOaF  
s%c
>Ge  
4
T<4Rb[  
/* DtrR< &m  
**FileAccess.java ~vMdIZ.h  
*//文件访问(定位，写) g!*5@k|C  
package NetFox; 7Fd`MTo  
import java.io.*; p,'Z{7HG  
yoc;`hO-  
y +2  
public class FileAccessI implements Serializable{ CW)JS3}W"  
?!B
f# "TY  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节  5gZ6H/.  
RandomAccessFile oSavedFile; ]:X# w0UR  
long nPos; <*'%Xgm  
$wBF'|eU  
znxP.=GB   
public FileAccessI() throws IOException ]dj W^C]94  
{ ].e4a;pt  
this("",0); !/;/ X\d  
} &?)? w-$p  
~#^suy?  
t5"g9`AL  
public FileAccessI(String sName,long nPos) throws IOException i3[%]_eP.  
{ m:  
oSavedFile = new RandomAccessFile(sName,"rw"); yur5"$n  
this.nPos = nPos; a6<UMJ  
oSavedFile.seek(nPos); &uMx*TTY  
} d)yu`U  
Vw>AD<Rl  
[S<1|hk s(  
public synchronized int write(byte[] b,int nStart,int nLen) bCbpJZ  
{
jr`;H  
int n = -1;
U-mZO7y!  
try{ YooPHeQ  
oSavedFile.write(b,nStart,nLen); 2^;zj0]Rt  
n = nLen; V }?MP-.c  
} rTmVHt  
catch(IOException e) r|,_qNrw  
{ dvX
[,*wz  
e.printStackTrace (); I)YUGA5  
} j'QPJ(`~1l  
K}j["p<!  
P]mJ01@'  
return n; \fD)|  
} t|jp]Vp  
FJCLK#-  
ALY3en9,  
} d"0=.sA  
)kpNg:2p  
5"WI^"6b:  
/* qvs&*lBY  
**SiteInfoBean.java ARd*c?Om  
*/ fuQk}OW{  
package NetFox; L4t(Y7  
&rbkw<=j  
Mc@_[q!xY?  
public class SiteInfoBean { fG_<HJS(~  
_X]\#^UiO2  
!(8)'<t9  
private String sSiteURL; //Site's URL 8quH#IhB  
private String sFilePath; //Saved File's Path ZTg[}+0e  
private String sFileName; //Saved File's Name >.1d1#+b  
private int nSplitter; //Count of Splited Downloading File mTU[khEmL=  
e,DRQ2AU  
5I>a|I!j  
public SiteInfoBean() dIq*"Ry+~  
{//nSplitter的缺省值为5 @=NTr  
//default value of nSplitter is 5 GvTA/zA  
this("","","",5); qF3s&WI  
} K0'= O  
TR&7AiqB  
'TO/i:{\  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %$6?em_  
{ u/.# zn@9h  
sSiteURL= sURL; +k{l]-)1  
sFilePath = sPath; Q79WGW  
sFileName = sName; 8JojKH  
this.nSplitter = nSpiltter; 9l<}`/@}W  
U:q4OtiP  
OD6dMql  
} 9yYNX;C  
AK//]   
a^eR~efdu@  
public String getSSiteURL() "BA&  
{ 9WT{~PGj  
return sSiteURL; E4N"|u|  
} SNrX(V::z  
Aj{G=AT  
:qvA'.L/;z  
public void setSSiteURL(String value) R+5yyk\  
{ d04fj/B  
sSiteURL = value; UWW'[gEP1  
} ;-quK%VO!  
Z\S'HNU  
#Fckev4  
public String getSFilePath() B,4 3b O  
{ ,E&W{b  
return sFilePath; Q;k D Jo  
} @g]>D  
S76xEL  
$VJE&b  
public void setSFilePath(String value) "\O{!Hj8  
{ J?/NJ-F  
sFilePath = value; nkkUby9  
} c?}{>ig/)  
i;<K)5Z  
)&[Zw{6P  
public String getSFileName() wpf  
{ `,s0^?_  
return sFileName; M
i<}q@]e  
} V;(Rg=5  
|]'gd)%S\  
H><! C  
public void setSFileName(String value) )VeeAu)p  
{ L"'L@A|U  
sFileName = value; EASN#VG  
} 'e*:eBoyb  
3A'9=h,lVK  
fiQ/ &]|5  
public int getNSplitter() F-<c.0;6  
{ vpP8'f.  
return nSplitter; ]D@y""{--s  
} CA3`Ee+rD  
6#Bg99c  
uiq;{!dop  
public void setNSplitter(int nCount) q)!G5j3  
{ q]DE\*@  
nSplitter = nCount; F>ps&h  
} i|N(=Z=  
} A&`7 l5~X  
Q32GI,M%B  
D' `[y  
/* zvKypx  
**Utility.java z<u@::  
*/ v;:. k,E0  
package NetFox; tRXR/;3O  
2l}3L  
ee*E:Ltz\  
public class Utility { Za'
}26  
eXQzCm  
#4{9l SbU  
public Utility() +.|8W!h`1  
{ lt|UehJF  
ePY69!pO5e  
ol@LLT_m  
} TN.&FDqC9  
N=;V
S-  
//线程睡眠 fHacVjJ  
public static void sleep(int nSecond) 4Dv42fO  
{ ILT.yxV  
try{ 5u
D'Kd$H  
Thread.sleep(nSecond); J-Wphc!m  
} 3ms{gZbw  
catch(Exception e) i]IZ0.?Y  
{ bEl)/z*gy/  
e.printStackTrace (); q6zKyO
E  
} h9j/mUwV  
} oT[8Iu  
z/t+t_y  
//日志 _.BX#BIF  
public static void log(String sMsg) uDG#L6  
{  `AxhA.&V  
System.err.println(sMsg); :\,3=suWq  
} &+7G|4!y  

J@Qw6J  
psAdYEGk!  
public static void log(int sMsg) :a y-2  
{ ^?gs<-)B  
System.err.println(sMsg); zP#%ya:I  
} 1}jwv_0lL  
} &g
5+ |g (  
y%xn(Bn  
dS"%( ?o  
/* P:2 0i*QU  
**TestMethod.java ewv[nJD$  
*/ hFr?84sAd  
package NetFox; M;F&Ix  
:EZ"D#>y~  
+)-`$N  
public class TestMethod { L }&$5KiwV  
wEJ?Y8  
($Y6hn+  
public TestMethod() a%)-iL X8&  
{ ///xx/weblogic60b2_win.exe VU 8~hF  
try{ %)G]rta#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); MYF6tZ*  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); nh+f,HtSt  
SiteFileFetch fileFetch = new SiteFileFetch(bean); . [5{  
fileFetch.start(); -<.b3Mh  
} mqb6MnK -  
catch(Exception e){e.printStackTrace ();} e$y VV#  
M}BqSzd*  
\hFIg3  
} >$p|W~x  
cQldBc  
l]v>PIh~N  
public static void main(String[] args) PK|"+I0  
{ Ae 3:"  
new TestMethod(); xk$U+8K  
} cG~-OHU  
} A?/(W_Gt^M  
点击下载更多相关资料