http断点续传简单实现（java)

/* -R@mnG 5  
**SiteFileFetch.java 0@[]l{N  
*/ Kf#9-.}?  
package NetFox; S*<+vIo  
import java.io.*; 7<
['4*u  
import java.net.*; 1*<m,.$  
jh\L)a*  
XOK.E&eilj  
public class SiteFileFetch extends Thread { Lgl%fO/<t  
Bfwa1#%?  
," ~ew ,  
SiteInfoBean siteInfoBean = null; //文件信息Bean c.y8x  
long[] nStartPos; //开始位置 ]wCg'EUB  
long[] nEndPos; //结束位置 f]N2(eM  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 kKwb)i  
long nFileLength; //文件长度 /iFtW#K+  
boolean bFirst = true; //是否第一次取文件 uc4#giCD  
boolean bStop = false; //停止标志 /pni_-l*  
File tmpFile; //文件下载的临时信息 r=lhYn  
DataOutputStream output; //输出到文件的输出流 3:1 h:Yc<  
Xi`K`Cu+  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） [h20y  
public SiteFileFetch(SiteInfoBean bean) throws IOException -E_lwK  
{ `MtI>x c  
siteInfoBean = bean; -:]_DbF  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ~LqjW
U  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); v8Gm;~  
if(tmpFile.exists ()) BMMWP
 
{ ?v?b%hK!;  
bFirst = false; ^"N]i`dIF  
read_nPos(); kX!TOlk3  
} H.#<&5f  
else R@_i$Df|  
{ c+P.o.k;  
nStartPos = new long[bean.getNSplitter()]; uaN0X"  
nEndPos = new long[bean.getNSplitter()]; (F9U`1~4  
} -)_"7}|u5  
seO7/h_a  
KLi&TmIB  
R+Q..9P  
} >.^/Z/[.L  
H0tjBnu   
$2N)m:X0  
public void run() uh#"4-v  
{ HAJK%zLc  
//获得文件长度 CYD&#+o  
//分割文件 t/xWJW2  
//实例FileSplitterFetch w+c%Y\:  
//启动FileSplitterFetch线程 ]
Q-*xho  
//等待子线程返回 <pzCpF<  
try{ /~RY{ c@#L  
if(bFirst) HX\^ecZ#E  
{ iOk^RDG+  
nFileLength = getFileSize(); xfYDjf :<  
if(nFileLength == -1) Bo.< 4P  
{ znm3b8ns  
System.err.println("File Length is not known!"); RQ}0f5~t  
} 6Ap-J~4  
else if(nFileLength == -2) q5<'pi   
{ BVAxeXO  
System.err.println("File is not access!"); (/6~*<ZGT  
} k$j4~C'$  
else q^5j&jx Vl  
{ tB-0wD=PR  
for(int i=0;i<nStartPos.length;i++) JRfG]u6GU  
{ N,N9K  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); BWRM gN'.  
} 4H@:|  
for(int i=0;i<nEndPos.length-1;i++) R0|dKKzS  
{ h$3o]~t  
nEndPos = nStartPos[i+1]; a'3|EWS ?  
} K1i@.`na/$  
nEndPos[nEndPos.length-1] = nFileLength; B
.)!zv\{  
} Lh eOGM  
} DL$O274uZ  
XNODDH  
`
<}Q4p  
//启动子线程 _`'VOY`o  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Wx~N1+  
for(int i=0;i<nStartPos.length;i++) ,T:Uk*Bj  
{ Q7u/k$qN  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), i|5.DhK}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {p -q&k&R|  
nStartPos,nEndPos,i); |ipL.<v7  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); BCy# Td  
fileSplitterFetch.start(); 7Aj o9  
} 
>/W  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), PHZ+u@AA6@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <:(pnw*L  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 0^?:Zds  
nEndPos = " + nFileLength); U7GgGMw  
// fileSplitterFetch[nPos.length-1].start(); X9ua&T2(l  
`cu W^/c  
%9 kOl  
//等待子线程结束 fjD/<`}v  
//int count = 0; YVSAYv_ZG}  
//是否结束while循环 SxyXz8+e[  
boolean breakWhile = false; ^t X}5i`P  
}2@Aj  
*2nQZ^c.  
while(!bStop) ;/hR#>ib  
{ :!',o]"4,k  
write_nPos(); K+2sq+3q  
Utility.sleep(500); ~8fy qE$  
breakWhile = true; 7sgK+ ip  
wlSl ~A/s  
Q7V*~{  
for(int i=0;i<nStartPos.length;i++) $q}zW%  
{ G3[X.%g`  
if(!fileSplitterFetch.bDownOver) v@_^h}h/,=  
{ |AgdD  
breakWhile = false; j%_{tB  
break; ?%)G%2  
} yH
YqJ|t  
} `;X~$uS  
if(breakWhile) ..Q$q2.  
break; )1E[CIaXK  
qeM`z  
l:' 0  
//count++; ,q[aV 6kO  
//if(count>4)
(TKn'2  
// siteStop(); d'bAM{R>  
} aXOW +$,  
f}1B-  
kfb*|  
System.err.println("文件下载结束！"); VR5CRNBJ  
} B4uJT~,7>  
catch(Exception e){e.printStackTrace ();} ]6)~Sj$ 5  
} Ev%_8CO4e  
$9~6M*  
H YA<  
//获得文件长度 _BC%98:WP  
public long getFileSize() ,}8|[)"  
{ )\xDo<@  
int nFileLength = -1; >0^oC[ B  
try{ .N:& {$o:  
URL url = new URL(siteInfoBean.getSSiteURL());  ~OdE!!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -MA/:EB  
httpConnection.setRequestProperty("User-Agent","NetFox"); nu=yE$BN{  
Njp?/r  
O1C|{ M  
int responseCode=httpConnection.getResponseCode(); 2b&&3u8  
if(responseCode>=400) 9n\b
!*x  
{ htgtgW9 ^P  
processErrorCode(responseCode); &>jSuvVT  
return -2; //-2 represent access is error AbqeZn  
} pgp@Zw)r)k  
%1\MW+  
ftaGu-d%  
String sHeader; JI)@h 4b  
6}q
8%[l|  
6ct'O**k*&  
for(int i=1;;i++) +m
gm39  
{ Es7+bFvsE8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); f!H~BMA+a  
//Utility.log(in.readLine()); WUN|,P`b  
sHeader=httpConnection.getHeaderFieldKey(i); \vKKq/f  
if(sHeader!=null) gG?sLgL:  
{ "A4.2  
if(sHeader.equals("Content-Length")) d_ [l{  
{ f+WN=-F\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); per$%;5E"  
break; k Q Sx65  
} R&vV!d  
} 2oO&8:`tv  
else ?FV>[&-h#I  
break; >GV(\In  
} )qq5WShMJ  
} mFGiysM  
catch(IOException e){e.printStackTrace ();} DI>SW%)>  
catch(Exception e){e.printStackTrace ();} z\kiYQ6kA  
eH0^d5bH  
p?6`mH  
Utility.log(nFileLength); EFk9G2@_  
)XFaVkQ}  
I1Jhvyd?$  
return nFileLength; $FJf8u`  
}  << X
WL:  
'{-7%>`bn  
;A\SbLM  
//保存下载信息（文件指针位置） Y8s.Q  
private void write_nPos() .)Wqo7/Gx  
{ .%x1%TN  
try{ 0]~'}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3hD
\6,@  
output.writeInt(nStartPos.length); '0jjoZ:  
for(int i=0;i<nStartPos.length;i++) Cih~cwE  
{ rBLcj;,
 
// output.writeLong(nPos); 4.t72*ML  
output.writeLong(fileSplitterFetch.nStartPos); IEP^u `}  
output.writeLong(fileSplitterFetch.nEndPos); SQSPdR+  
} Q7{/ T0  
output.close(); 7_G$&  
} mne?r3d  
catch(IOException e){e.printStackTrace ();} O]1aez[  
catch(Exception e){e.printStackTrace ();} -Uj3?W  
} )8_x  
1SwKd*aRR?  
phc9esz  
//读取保存的下载信息（文件指针位置） JNx;/6'd,  
private void read_nPos() x^959QO~  
{ ^sP-6 ^  
try{ \F'tl{'\@  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));
#GVf+8"  
int nCount = input.readInt(); 02F\1fXS  
nStartPos = new long[nCount]; 2 {I(A2  
nEndPos = new long[nCount]; yh'P17N|q  
for(int i=0;i<nStartPos.length;i++) <J o\RUx  
{ ],l}J'.8<V  
nStartPos = input.readLong(); |z 8Wh  
nEndPos = input.readLong(); 4?c4GT9(6S  
} qF? n&>YG  
input.close(); )wb&kug-  
} <l`xP)] X  
catch(IOException e){e.printStackTrace ();} _@/nc:)H  
catch(Exception e){e.printStackTrace ();} XD8Q2un  
} sWGc1jC?.F  
GU,ztO.w3  
fgW>~m.W  
private void processErrorCode(int nErrorCode) Yp@i{$IUW  
{ B*AF8wX|  
System.err.println("Error Code : " + nErrorCode); ] v8.ym  
}
~2L]K4Z^  
ZDl6F`  
p|&9#?t4A  
//停止文件下载 aBblP8)8;K  
public void siteStop() 7O]$2  
{ 0Q)m>oL.  
bStop = true; IPDQ  
for(int i=0;i<nStartPos.length;i++) qi]"`\  
fileSplitterFetch.splitterStop(); lmbC2\GT  
T[\?fSP  
6p)dO c3L  
} @ |^;d  
} Ni Y.OwKr  
//负责部分文件的抓取 %h^ f?.(:  
**FileSplitterFetch.java NN"!kuM  
*/ N_Q\+x}zq  
package NetFox; \ 0J&^C  
JIh:IR(ta  
RbN# dI'  
import java.io.*; 9J(jbJ7p  
import java.net.*; B4kJ 7Pdny  
tvEf-z  
{IG5qi?/E)  
public class FileSplitterFetch extends Thread { 1c19$KHu  
abw7{%2  
C9Xj)5k@R  
String sURL; //File URL 6 66f
;h  
long nStartPos; //File Snippet Start Position O
g E<bw  
long nEndPos; //File Snippet End Position vNIQ1x5Za  
int nThreadID; //Thread's ID YCI-
p p  
boolean bDownOver = false; //Downing is over # M18&ld,r  
boolean bStop = false; //Stop identical h3BDHz,  
FileAccessI fileAccessI = null; //File Access interface qP4vH]  
cP,bob]  
<"HbX  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException <UE-9g5?G  
{ w\`u|f;Aq  
this.sURL = sURL; < /\y<]b  
this.nStartPos = nStart; ;Svs|]d  
this.nEndPos = nEnd; eW/sPQ-  
nThreadID = id; n/vKxtW  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 FJH'!P\  
} !W48sZr1&  
F\BD7W  
p`mNy o'  
public void run() TChKm-x  
{ tO8<N'TD  
while(nStartPos < nEndPos && !bStop) /5&'U!:+  
{ 7 yp}  
*)82iD  
>u/ T`$  
try{ <xO" E%t  
URL url = new URL(sURL); N~0~1 WQn  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); N[j*Q 8X_  
httpConnection.setRequestProperty("User-Agent","NetFox"); a%N
SL6  
String sProperty = "bytes="+nStartPos+"-"; 0sGAC  
httpConnection.setRequestProperty("RANGE",sProperty); G Z~W#*|V  
Utility.log(sProperty); $`'Xb  
RA^-Pa.O  
m0[JiwPI  
InputStream input = httpConnection.getInputStream(); w^N3Ma  
//logResponseHead(httpConnection); s;!Tz)  
p)y'a+|7  
-V'h>K  
byte[] b = new byte[1024]; (I0QwB  
int nRead; 8TV "9{ n  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?o883!&v  
{ vC|V8ea  
nStartPos += fileAccessI.write(b,0,nRead); xa]e9u%  
//if(nThreadID == 1) ['#3GJz-  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); )DwHLaLW  
} @yxF/eeEy+  
8D5v'[j-  
0k):OVfm=  
Utility.log("Thread " + nThreadID + " is over!"); :o=a@Rqx  
bDownOver = true; TW)~&;1
l  
//nPos = fileAccessI.write (b,0,nRead); kD{qW=Lpn  
} _=ziw|zI  
catch(Exception e){e.printStackTrace ();} w\(;>e@  
} Xn3 \a81  
} A2{s?L,  
[)KLmL%  
u~\I  
//打印回应的头信息 s$PPJJT{b  
public void logResponseHead(HttpURLConnection con) XPd@>2  
{ r.#"he_6!.  
for(int i=1;;i++) _+NM<o#A  
{ YfZ96C[a  
String header=con.getHeaderFieldKey(i); f>kW\uC  
if(header!=null) EI!e0V1!  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); f.Feo  
Utility.log(header+" : "+con.getHeaderField(header)); 8-uRn38  
else Y>i5ubR~  
break; b@?pofZ`k  
} vzPuk|q3  
} c2fqueK|:W  
eA'1  
p"k[ac{  
public void splitterStop() tShyG!b  
{ dp~] Wx  
bStop = true; m%[`NP (  
} zM+eb| >cr  
'%\FT-{  
p"ElO,\  
} ZCuLgCP?Z  
e=#'rDm  
;fl3'.S[  
/* 2uy<wJE>  
**FileAccess.java ocDAg<wo  
*//文件访问(定位，写) ]46#u=y~3  
package NetFox; k<i#agq  
import java.io.*; LktH*ePO  
`%
nj$-W:  
AttS?TZr  
public class FileAccessI implements Serializable{ /@`kM'1:  
l %M0^d6M  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 h.WvPZ2U  
RandomAccessFile oSavedFile; Ka|, qkb  
long nPos; C<u<:4^H  
&|&tPD/dJ  
T=D|jt  
public FileAccessI() throws IOException wOU\&u|
 
{ fOtzbYVC  
this("",0); JK_(!  
} uE%$<o*#  
t~(|2nTO5  
D/x!`&.sN  
public FileAccessI(String sName,long nPos) throws IOException O\&[|sGY{  
{ >J,y1jzJ  
oSavedFile = new RandomAccessFile(sName,"rw"); \I[50eh|  
this.nPos = nPos; 
.QVZ!  
oSavedFile.seek(nPos); N_^s;Qj  
} n)xLEx,  
p81Vt  
>jH%n(TcC  
public synchronized int write(byte[] b,int nStart,int nLen) g*%z{w  
{ ~&\}qz3  
int n = -1; /.>
8e%)  
try{ 2(5<Wj"  
oSavedFile.write(b,nStart,nLen); I2G:jMPy  
n = nLen; .{ +Obi  
} H4{CiZ  
catch(IOException e) DLBHZ?+!  
{ rD":Gac  
e.printStackTrace (); f9FEH7S68  
} PbpnjvVrM  
NuQ l  

<A+n[h  
return n; 5N.-m;s  
} 6! .nj3$*  
yuA+YZ  
i$CN{c*  
} Al-;-t#Dc  
?=#vp /  
yMVlTO  
/* "`q:
  
**SiteInfoBean.java |X6/Y@N  
*/ *JT,]7>  
package NetFox; Z(c3GmY  
x4=Sm0Ro|V  
[QZ g=."  
public class SiteInfoBean { h}$g}f%$+  
ZlG|U]mM5  
m]Gxep0%  
private String sSiteURL; //Site's URL rK@XC +`S  
private String sFilePath; //Saved File's Path nkTpUbS'f?  
private String sFileName; //Saved File's Name A
S? ESDC  
private int nSplitter; //Count of Splited Downloading File 0*^>/*  
' Ih f|;r  
='G-wX&k  
public SiteInfoBean() 3LW_qX  
{//nSplitter的缺省值为5 0aM&+j\q}  
//default value of nSplitter is 5 =IH~:D\&  
this("","","",5); o|G[/o2  
} XDQ5qfE|  
c$P68$FB  
A}3dx!?7j  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 7U647G(Sg  
{ OUF
x M  
sSiteURL= sURL; 1"yr`,}?8r  
sFilePath = sPath; n4sO#p)'  
sFileName = sName; r?2EJE2{V  
this.nSplitter = nSpiltter; ,[UK32KWI  

%iR"eEE  
fK{m7?V  
} Em ;2fh  
)eD9H*mq  
(J 1:J  
public String getSSiteURL() GTuxMg`  
{ nr]:Y3KyxX  
return sSiteURL; sOqT*gwr:  
} hZ`<ID  
sXaudT  
N3(.7mxo  
public void setSSiteURL(String value) ORx6r=zg  
{ qd<-{  
sSiteURL = value; Lvd es.0|  
} cNl NJ  
L+.&e4f'oj  
E< Y!BT[X  
public String getSFilePath() q>rDxmP<  
{ ^V7'
S<  
return sFilePath; c:I %j
m  
} NH'Dz6K5  
l=PZlH y1G  
0PD=/fh[  
public void setSFilePath(String value) _)kTlX:,  
{ U!i1~)s  
sFilePath = value; ]_(J8v  
} G _-JR  
B",;z)(%  
"IN[(  
public String getSFileName() Qg]+&8!*  
{ +3F%soum95  
return sFileName; =1Hn<Xay0  
} p?2^JJpUb  
D/YMovH%  
i_e%HG  
public void setSFileName(String value) Dv"HFQuF  
{ Marx=cNj
 
sFileName = value; UQ#t &  
} )uu(I5St  
+L|x^B3  
b/"gUYo  
public int getNSplitter() >@)p*y.K  
{ $f?GD<}?7r  
return nSplitter; v>0I=ut  
} p"
"\uG'  
+"1fr  
ykYef  
public void setNSplitter(int nCount) m+Kl   
{ (YM2Cv{4  
nSplitter = nCount; 6Ts[NXa  
} }jg1..)"<  
} N*+L'bO  
OcLahz6  
)G),iy  
/* JNv@MJb}  
**Utility.java "`NAg  
*/ GTM@9^  
package NetFox; 0`V;;w8  
xzHb+1+p  
[/o BjiBA  
public class Utility { 8]mRX~  
B$M4f7  
6UI6
E)g  
public Utility() "5204I  
{ -tIye{  
iPdS>ee  
lAR1gHhJ  
} K
r?<7vMT5  
~BiLzT1,  
//线程睡眠 Gz52^O:  
public static void sleep(int nSecond) bFhZSk)  
{ "U!Vdt2vp  
try{ =~
k}XB  
Thread.sleep(nSecond); #(QS5J&Qq  
} +Sc2'z>R  
catch(Exception e) zZ,"HY=jN  
{ ++n_$Qug  
e.printStackTrace (); xR8y"CpE  
} ~ mzX1[  
} =h xyR;  
#jJ0
Mxg  
//日志 ZUD{V  
public static void log(String sMsg) P?^%i  
{ !mmSF1f  
System.err.println(sMsg); Tm$8\c4V:*  
} w
_4O;  
[dFe-2u ,$  
\l%##7DRp]  
public static void log(int sMsg) V-3;7  
{ Cp+tcrd_s  
System.err.println(sMsg); Fi/`3A@68  
} :}2Tof2  
} hBaF^AWW  
j\"d/{7Q  
>{l b|Vx  
/* KrR`A(=WL  
**TestMethod.java LP !d|X  
*/ -(7oFOtg  
package NetFox; m%'T90mi  
bI^F(  
-Kw7! =_ g  
public class TestMethod { Kn1T2WSAg  
`6RccEm  
\r9E6LLX'  
public TestMethod() #l
h' !  
{ ///xx/weblogic60b2_win.exe M N (o  
try{
6VS_
L@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [+8*}03  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1/,~0N9  
SiteFileFetch fileFetch = new SiteFileFetch(bean); EI)2c.A  
fileFetch.start(); -?l`LbD  
} @-Y,9mM  
catch(Exception e){e.printStackTrace ();} }u8g7Nj  
@REMl~"D5  
xs )jO+.  
} R#i`H(N  
2a;[2':  
W7;R
Q  
public static void main(String[] args) Al]*iw{  
{ O\gVB!x  
new TestMethod(); 6Eus_aP  
} jcjl q-x  
} 7{l~\]6d  
点击下载更多相关资料