http断点续传简单实现（java)

/* _3wJ;cn.  
**SiteFileFetch.java RgFpc*.T  
*/ "fNv(> -7s  
package NetFox; jS3@Z?x?*  
import java.io.*; anz7ae&P'K  
import java.net.*; `::j\3B&Y-  
Us "G X_  
Ap\]v2G  
public class SiteFileFetch extends Thread { 6
T~+vT  
Kg2@]J9m  
(AA@sN  
SiteInfoBean siteInfoBean = null; //文件信息Bean xF)
 .S@  
long[] nStartPos; //开始位置 *]q`:~u2  
long[] nEndPos; //结束位置 oU3gy[wF;b  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 n@@tO#!\  
long nFileLength; //文件长度 tZ=|1lM  
boolean bFirst = true; //是否第一次取文件 /Tl ybSC1  
boolean bStop = false; //停止标志 )N{PWSPs  
File tmpFile; //文件下载的临时信息 8z=o.\@  
DataOutputStream output; //输出到文件的输出流 "e\73?P  
O+XQP!T  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） oKSW:A  
public SiteFileFetch(SiteInfoBean bean) throws IOException W{ozZuo  
{ wAR:GO'n  
siteInfoBean = bean; Y uZ
  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); K'e!BZm6Q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jj `0w@  
if(tmpFile.exists ()) T2W^4)  
{ -=rGN"(M _  
bFirst = false; T;3~teVYB  
read_nPos(); )`5-rm~*  
} D//58z&  
else O{]}{Ss  
{ {XhpxJ__  
nStartPos = new long[bean.getNSplitter()]; )}w-;HX  
nEndPos = new long[bean.getNSplitter()]; 2s 9U&  
} +f]I7e:qp  
ZMyd+C_P2  
c:z}$DK&'  
Q
QHC 1  
} 6*ZZ)W<  
Tig6<t+Q  
,,9vk\  
public void run() %u|Qh/?7  
{ Z#%77!3  
//获得文件长度 )Knsy  
//分割文件 qj*BV  
//实例FileSplitterFetch /e*<-a  
//启动FileSplitterFetch线程 z9#jXC#OdN  
//等待子线程返回 f}FJR6VO  
try{ EjVB\6,  
if(bFirst) y;9K
 
{ NVC$8imip  
nFileLength = getFileSize(); =g@hh)3wP  
if(nFileLength == -1) @izS_I,  
{ ";0-9*I  
System.err.println("File Length is not known!"); H<b4B$/  
} 4f0dc\$  
else if(nFileLength == -2)
\BsvUGd  
{ WWTJ%Rd|  
System.err.println("File is not access!"); yNx"Ey dk`  
} 1^;&?E  
else <* PjG}Z.  
{ x~yd/ R  
for(int i=0;i<nStartPos.length;i++) HZ2zL17  
{ KRcg  
nStartPos = (long)(i*(nFileLength/nStartPos.length));  93`  
} QPF[D7\  
for(int i=0;i<nEndPos.length-1;i++) |4Q><6"G  
{ Ox/va]e7"  
nEndPos = nStartPos[i+1]; K&Q0]r?  
} v:j4#pEWD  
nEndPos[nEndPos.length-1] = nFileLength;
wIbc8ze  
} C$B?|oUJc  
} ;#"`]khd  
gD fVY%[Z  
pm;g)p?  
//启动子线程 9Bmgz =8  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; JeCEj=_Z  
for(int i=0;i<nStartPos.length;i++) X_|} b[b  
{ %^E>~  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `[1]wV5(5@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Md m(x
Us  
nStartPos,nEndPos,i);  })w5`?Y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a-DE-V Uls  
fileSplitterFetch.start(); :Ws3+OI'm3  
} *KV]MdS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qdu:kA:]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 1-gX=8]]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", WI'csM;M#  
nEndPos = " + nFileLength); ma*9O |v^  
// fileSplitterFetch[nPos.length-1].start(); 4';['  
kQBVx8Uq]  
<~8W>Y\m  
//等待子线程结束 tv|=`~Y  
//int count = 0;
`^N;%[c`z  
//是否结束while循环 .g&BA15<F6  
boolean breakWhile = false; E3KPJ`=!*"  
,9M \`6  
N4mQN90t  
while(!bStop) aH$*Ue@Q  
{ DwTZ<H4  
write_nPos(); +Q_Gm3^  
Utility.sleep(500);  L_Ai/'
 
breakWhile = true; Ri-wbYFaP  
z?YGE iR/}  
T +4!g|Y  
for(int i=0;i<nStartPos.length;i++) Ip1Qm
P  
{  y.eBFf  
if(!fileSplitterFetch.bDownOver) ;NPb  
{ %r,2ZLZ  
breakWhile = false; *'t`;m~  
break; }&naP  
} W]*wxzf!5z  
} Hm^p^,}_x  
if(breakWhile) mg;AcAS.o,  
break; ,zyrBO0 Eq  
_bz,G"w+:  
b
o"I:)n;  
//count++; Tp6ysjao  
//if(count>4) },L[bDOV07  
// siteStop(); %E!0,y,:  
} fu&]t8MJC  
5Np.&  
XZT( :(  
System.err.println("文件下载结束！"); '}Y8a$(;V  
} =gqZ^v&5U  
catch(Exception e){e.printStackTrace ();} ?3, *  
} hg>YOf&RG  
! O>mu6:Rf  
Yr,1##u  
//获得文件长度 Tuy*Df  
public long getFileSize() 5astv:p,P  
{ M
U^Z*r  
int nFileLength = -1; )T+htD)  
try{ J\0YL\jw1K  
URL url = new URL(siteInfoBean.getSSiteURL()); y@z#Jw<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^b.J z}  
httpConnection.setRequestProperty("User-Agent","NetFox"); \5l}5<|  
TPzoU" qh  
v>P){VT  
int responseCode=httpConnection.getResponseCode(); ?d%}K76V<  
if(responseCode>=400) ixkg,  
{
5~? J  
processErrorCode(responseCode); abv]  
return -2; //-2 represent access is error TP^0`L  
} 0nuFWV  
A,/S/_Q=  
5V
cYdu3  
String sHeader; ']NM_0  
O#|E7;  
M;bQid@BG  
for(int i=1;;i++) S{H8}m|MW  
{ m ;vN
A  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 5f5`7uVJF  
//Utility.log(in.readLine()); s_8!x  
sHeader=httpConnection.getHeaderFieldKey(i); uQNoIy J)  
if(sHeader!=null) 1WKDG~  
{ h 2zCX  
if(sHeader.equals("Content-Length")) sOW|TN>y\  
{ J.d `tiN  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); mB~&nDU  
break; PrcM'Q  
} _Owz%  
} M@3H]t?  
else :U>
oW97l  
break; XDGZqkt  
} 1&<@(S<  
} VQ;=-95P  
catch(IOException e){e.printStackTrace ();} Xz@>sY>Jc  
catch(Exception e){e.printStackTrace ();} "8I4]
'  
l]Sui_+ZU  
8K/lpqw  
Utility.log(nFileLength); xl^'U/  
ZjK~s)RC  
;sf/tX  
return nFileLength; +A3H#'  
} a*8}~p,  
HKwGaCj`  
|"< I\Vs:  
//保存下载信息（文件指针位置） !|/fVWH  
private void write_nPos() 
uI[*uAR  
{ )em.KbsPPF  
try{ GwULtRa/  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -iHhpD9"X  
output.writeInt(nStartPos.length); :KLD~k7yA(  
for(int i=0;i<nStartPos.length;i++) I
Y&a!  
{ ;z>YwRV  
// output.writeLong(nPos); "gz;Q  
output.writeLong(fileSplitterFetch.nStartPos); ;~J~
g
#  
output.writeLong(fileSplitterFetch.nEndPos); 
df'g},_  
} L9@jmh*E  
output.close(); UK,P?_e  
} :Mk}Suf&H  
catch(IOException e){e.printStackTrace ();} [1U_c*;i  
catch(Exception e){e.printStackTrace ();} QFYy$T+W  
} a6d
KQ3D  
I'C,'  
lUEyo.xVt  
//读取保存的下载信息（文件指针位置） &?nF';&  
private void read_nPos() 1^3#3duV  
{ di5_5_$`o  
try{ A@OV!DJe]  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); hz%IxI9  
int nCount = input.readInt(); j
lBCu(.,_  
nStartPos = new long[nCount]; Cs{f'I  
nEndPos = new long[nCount]; %"zJsYQ!  
for(int i=0;i<nStartPos.length;i++) Biwdb  
{ wrU[#g,uvr  
nStartPos = input.readLong(); -wfV  
nEndPos = input.readLong(); *zWn4BckN  
} 'r%oOZk)z  
input.close(); @\?f77Of6  
} 3D0I5LF&  
catch(IOException e){e.printStackTrace ();} z<>_*Lfj  
catch(Exception e){e.printStackTrace ();} (T01hR&  
} t,,^^ll  
v"+EBfx  
(&,R1dLo  
private void processErrorCode(int nErrorCode) d ] ;pG(  
{ )[*O^bPowI  
System.err.println("Error Code : " + nErrorCode); pt#[.n#f  
} F948%?a  
kVv <
tw  
xF;v 6d  
//停止文件下载 k;5}@3iQ  
public void siteStop() r.;iO0[/  
{ Gu).*cU  
bStop = true; wlM ?gQXU[  
for(int i=0;i<nStartPos.length;i++) w ZAXfNA  
fileSplitterFetch.splitterStop(); $4L3y uH  
(?y2@I}  
IcQ!A=lB  
} 5QJL0fc  
} /p0LtUMu  
//负责部分文件的抓取 us%RQ8=k  
**FileSplitterFetch.java m=B0!Z1xx  
*/ !++62Lf  
package NetFox; 9K<a}QJP  
eB*8)gYh  
;r"B?]JO  
import java.io.*; |$2N$6\SP  
import java.net.*; sEyl\GL  
oFR'GUQC  
TP::y  
public class FileSplitterFetch extends Thread { <v k$eB8EC  
]H~,K]@.  
/H@")je  
String sURL; //File URL XH$|DeAFM  
long nStartPos; //File Snippet Start Position a HL '(<  
long nEndPos; //File Snippet End Position -<]_:Kf{;&  
int nThreadID; //Thread's ID 0\@|M@X=  
boolean bDownOver = false; //Downing is over 5Suc#0y  
boolean bStop = false; //Stop identical ot#kU 8f  
FileAccessI fileAccessI = null; //File Access interface  a|uZJ*  
f"N3;,Oc  
l0if#?4\r  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException uTGvXKL7  
{ MPN=K|*  
this.sURL = sURL; ^\jX5)2{  
this.nStartPos = nStart; b]?;R  
this.nEndPos = nEnd; 4CT9-2UC  
nThreadID = id; RLNuH2y
;  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 .6o y>4  
} }F6b ]  
z %E!tB2o  
C&N4<2b  
public void run() s,H(m8#>  
{ {NgY8wQB  
while(nStartPos < nEndPos && !bStop) \3?;[xD  
{ B RjKV  
ArzsZ<\//  
d ovwB`5  
try{ JBAK*g  
URL url = new URL(sURL); XYF~Q9~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); VQMd[/  
httpConnection.setRequestProperty("User-Agent","NetFox"); }A/&]1GWk  
String sProperty = "bytes="+nStartPos+"-"; 6F/ OlK<  
httpConnection.setRequestProperty("RANGE",sProperty); jYID44$  
Utility.log(sProperty); k+GnF00N^8  
bI6wE'h  
7Sq{A@ET  
InputStream input = httpConnection.getInputStream(); +{!t~BW  
//logResponseHead(httpConnection); cG!2Iy~lA  
]f-'A>MC  
<D
;Q8  
byte[] b = new byte[1024]; 6v O)s!b  
int nRead; X3iRR{< @  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Ds,"E#?  
{ h=r< B\Pa  
nStartPos += fileAccessI.write(b,0,nRead); P3ev4DL  
//if(nThreadID == 1) L00;rTs>  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); J*KBG2+13  
} Tc5OI'-V  
)60f  
qS}RFM5|  
Utility.log("Thread " + nThreadID + " is over!"); j{Jc6U  
bDownOver = true; ZfCr"aL  
//nPos = fileAccessI.write (b,0,nRead); Qwo9>ClC  
} wDMB  
catch(Exception e){e.printStackTrace ();} 4m[C-NB!g  
} A6y~_dt  
} pjs9b%.  
c0Ro3j\p  
q=% C (  
//打印回应的头信息 Y1aF._Z  
public void logResponseHead(HttpURLConnection con) [piF MxZP  
{ hIo S#]  
for(int i=1;;i++) ^npS==Y]!.  
{ :F w"u4WI  
String header=con.getHeaderFieldKey(i); 7a]Zws  
if(header!=null) V -4*nV  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pMZf!&tM  
Utility.log(header+" : "+con.getHeaderField(header)); n.6 0$kR`  
else U2>dwn  
break; Fif^V  
} })Mv9~&S  
} cc(r,ij~4  
sa(M66KkU  
-WBz]GW4r  
public void splitterStop() xnuv4Z}]t  
{ mc=!X
  
bStop = true; .Jat^iFj0  
} Q()RO*9  
QDgEJ
%U-  
QD;f
~fZ  
} (6#yw`\  
H0b6ZA%n  
ivUsMhx>S,  
/* !0csNg!  
**FileAccess.java &Bz7fKCo  
*//文件访问(定位，写) V_A,d8=lt  
package NetFox; VfA5r`^  
import java.io.*; Xt,,AGm}  
KkL:p?@n  
h[ZN >T  
public class FileAccessI implements Serializable{ 6n6VEwYj  
/mBBeg^a  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 w]Ko/;;^2  
RandomAccessFile oSavedFile; 90h1e7Zc
C  
long nPos; :_QAjU  
^Im%D(MY  
uJ/?+5TU  
public FileAccessI() throws IOException 9<(K6Q  
{ 8K JQ(  
this("",0); +65~,e  
} YK?*
7  
jPYe_y  
Bpm5dT;  
public FileAccessI(String sName,long nPos) throws IOException Xlqz8cI  
{ T^%n!t  
oSavedFile = new RandomAccessFile(sName,"rw"); FH`'1iVH  
this.nPos = nPos; ADv"_bB:h  
oSavedFile.seek(nPos); {Sr=
SE  
} 'K@{vB  
r0g/:lJi  
97]a-)SA  
public synchronized int write(byte[] b,int nStart,int nLen) S-LZ(o{ZL  
{ SC $`  
int n = -1; >SxZ9T|%  
try{ @X|i@{<';  
oSavedFile.write(b,nStart,nLen); iy.%kHC  
n = nLen; @ Zgl>
  
} ULNAH`{D  
catch(IOException e) DNW2;i<hsz  
{ Ub'%pU  
e.printStackTrace (); ^`jZKh8)h  
} ;&W;  
lR@i`)'?U  
$nfBvf  
return n; J%\~<_2ny  
} %7(kP}y*  
>NH4A_  
>: W-C{%  
} 4QjWZ Wl  
[C+Gmu  
HL(U~Q6JQ  
/* H7yg9zFT N  
**SiteInfoBean.java o1#:j?sN  
*/ AJ#m6`M+EK  
package NetFox; "Ql}Y1  
E/dO7I`B   
( *9I
p  
public class SiteInfoBean { |,1bkJt  
/Oggt^S  
%7NsBR!y  
private String sSiteURL; //Site's URL W<rTq0~$?  
private String sFilePath; //Saved File's Path $@_<$t  
private String sFileName; //Saved File's Name G+hF [b44'  
private int nSplitter; //Count of Splited Downloading File Q_QKm0!  
iBKb/Oi6  
0E?s>-b  
public SiteInfoBean() 62MRI  
{//nSplitter的缺省值为5 WG8iTVwx  
//default value of nSplitter is 5 F%PwIB~cy  
this("","","",5); 0HHui7Yy>  
} uOG-IHuF  
43J\8WBn@  
$c@w$2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) X/E7o92\  
{ `sk!C7%  
sSiteURL= sURL; q6C6PPc  
sFilePath = sPath; eC>"my`  
sFileName = sName; 8:P*z  
this.nSplitter = nSpiltter; Zp7yaz3y  
N>A{)_k3  
'9*5-iO  
} Q5p+W  
${eY9-r_%  
/B,:<&_-  
public String getSSiteURL() RHwaJ;:)#  
{ =mHkXHE~:  
return sSiteURL; yHWi[7$  
} KMK&[E#r  
IU Y> ih  
:H!(?(Pie  
public void setSSiteURL(String value) k'[ S@+5  
{ * MSBjH|  
sSiteURL = value; 0^GbpSW{  
} ;m@1Ec@*p  
x7P([^i  
Sc1+(z  
public String getSFilePath() > $w^%I  
{ Q;$ 9qOF  
return sFilePath; W NwJM  
} s;fVnaqG:  
zU f>db  
uFwU-LCe  
public void setSFilePath(String value) )\T@W  
{ $^W-Wmsz  
sFilePath = value; F . K2  
} 5l41Q  
On{~St'V
 
gohAp
 
public String getSFileName() ]ZzoJ7lr  
{ uQGz;F x  
return sFileName; AVXX\n\_  
} AIZW@Nq.5  
"wA0 LH_  
 20I4r  
public void setSFileName(String value) a'@-"qk  
{ $uEJn&n7}  
sFileName = value; Xw7{R  
} 'oz hz2s  
^ckj3Y#;  
Yv)Bj  
public int getNSplitter() yWj9EHQU[  
{ 5/& 1Oxo  
return nSplitter; `%-4>jI9-  
} Y
]C;T  
hc-lzYS  
/635B*g  
public void setNSplitter(int nCount) 33Ssylno
 
{ 1&"-*)  
nSplitter = nCount; %ZujCZn  
} _9D|u<D  
} #|qm!aGs  
z^4KU\/JK  
FE/$(7rM  
/* zuUT S[  
**Utility.java i]it5  
*/ <=q*N;=T,  
package NetFox; puFXPw.3  
+
$>N]1
 
\,>_c  
public class Utility { ?VFM]hO  
w[ Axs8N'  
,LhEshf  
public Utility() -#hK|1]  
{ Q]< (bD.7  
2q)T y9  
6fh{lx>  
} |q3f]T&+>{  
]#F q>E  
//线程睡眠 Rr%tbt.sE  
public static void sleep(int nSecond) sz'p3  
{ jvu N  
try{ xN6>2e  
Thread.sleep(nSecond); wD`[5~C{  
} >G]?  
catch(Exception e) i-`,/e~XT  
{ )))2fskZ  
e.printStackTrace (); +H7y/#e+3  
} /:U1!9.y  
} 
AlO,o[0  
YU&4yk lE  
//日志 Ba<ngG !  
public static void log(String sMsg) SU/G)&Mi  
{ Q~phGD3!~  
System.err.println(sMsg); ]bIt@GB  
} brntE:  
~%`EeJwT  
gWkjUz)  
public static void log(int sMsg) |V lMmaz  
{ 8=:A/47=J  
System.err.println(sMsg); AWO0NWTB  
} PC|'yAN:  
} C5Xof|#p|  
't7Z] G  
qk&gA}qF  
/* sH%&+4!3  
**TestMethod.java s}wO7Df=+  
*/ :AZp}  
package NetFox; $57\u/(  
)]73S@P(=  
iAK/d)bq  
public class TestMethod { F#su5<d  
~P/]:=  
R;r|cep  
public TestMethod() kfXS_\@iW1  
{ ///xx/weblogic60b2_win.exe aVP5%  
try{ Vc|NL^  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); D3y>iQd
  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); TFO74^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); i-b1d'?Rb  
fileFetch.start(); CJp-Y}fGEA  
} ZPlPN;J^1  
catch(Exception e){e.printStackTrace ();} Tw
x{' S  
H<,bq*@  
Uj,g]e8e  
} okz]Qc>G  
EY~7oNfc`R  
! tGiTzzp  
public static void main(String[] args) UxeL cUP  
{ y1iX!m~)  
new TestMethod(); ?;^5ghY$  
} (k
8Z=/N~  
} /_q#ah  
点击下载更多相关资料