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http断点续传简单实现(java)

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/* \0vr>C  
**SiteFileFetch.java )Ccq4i  
*/ pXtXjb  
package NetFox; j{9D{  
import java.io.*; nAjO6g6E  
import java.net.*; [`rba'  
Q^e}?v%=%3  
Y<Fz)dQo  
public class SiteFileFetch extends Thread { {O`w,dMOI  
-Ty*aov  
D~$r\ ]av  
SiteInfoBean siteInfoBean = null; //文件信息Bean #R.-KUW:  
long[] nStartPos; //开始位置 NH<5*I/  
long[] nEndPos; //结束位置 _q{c##K f  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Ko&>C_N  
long nFileLength; //文件长度 =yyp?WmC8  
boolean bFirst = true; //是否第一次取文件 =aoMii   
boolean bStop = false; //停止标志 j"'(sW-  
File tmpFile; //文件下载的临时信息 m|:_]/*qE  
DataOutputStream output; //输出到文件的输出流 !=:$lzS^  
/x[jQM\  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 7|[mz> "d  
public SiteFileFetch(SiteInfoBean bean) throws IOException @>)r}b  
{ yX0dbW~@y  
siteInfoBean = bean; P:aJ#  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); .sj^{kGE  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d BJJZ^(  
if(tmpFile.exists ()) zOa_X~!@  
{ V*iH}Y?^p  
bFirst = false; LG1r]2  
read_nPos(); )Hk3A$6(  
} eK!V );  
else IuRmEL_Q_  
{ [ zEUH:9D  
nStartPos = new long[bean.getNSplitter()]; )_i qAqkS  
nEndPos = new long[bean.getNSplitter()]; vbD{N3p)?n  
} YGPy@-,E  
Wv/%^3  
/(BMG/Tb  
q~vDz]\G  
} Lg*B>=  
CS=qj-(  
}=8B*  
public void run() *]VFvh  
{ bdibaN-h  
//获得文件长度 p n.T~"%  
//分割文件 `/ q|@B7  
//实例FileSplitterFetch ,J{ei7TN  
//启动FileSplitterFetch线程 x>*Drm 7  
//等待子线程返回 v!ujj5-$I  
try{ yzLpK;  
if(bFirst) x\s|n{  
{ ^,;z|f'% *  
nFileLength = getFileSize(); , eZ1uBI?  
if(nFileLength == -1) Qi LEL  
{ %d(^d  
System.err.println("File Length is not known!"); eQD)$d_5  
} Y>EzTV  
else if(nFileLength == -2) w`il=ZAC  
{ 0 Emr<n  
System.err.println("File is not access!"); q"<acqK  
} (Xq)py9  
else .G)(0z("s  
{ -:Ia^{YN  
for(int i=0;i<nStartPos.length;i++) cg m~>  
{ f/Hm{<BY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 0;:.B j  
} Wr3mQU  
for(int i=0;i<nEndPos.length-1;i++) [I$ BmGQ  
{ \e'R @  
nEndPos = nStartPos[i+1]; <p\6AnkMr  
} YJ;j x0  
nEndPos[nEndPos.length-1] = nFileLength; |*'cF-lp6v  
} MF'$~gxo  
} G1"zElug  
0DmMG  
(h5'9r  
//启动子线程 Ar:*oiU  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; !2'jrJGc  
for(int i=0;i<nStartPos.length;i++) -sjd&)~S[  
{ ( |PAx (  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), \CXQo4P  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), :I:!BXQT$  
nStartPos,nEndPos,i); 4x;/HEb7?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  ?kZTI (  
fileSplitterFetch.start(); {FIXc^m'  
} %QKRFPYhS  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2cqI[t@0  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); x7<\] 94  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", =}v}my3y"  
nEndPos = " + nFileLength); j|/]#@Yr  
// fileSplitterFetch[nPos.length-1].start(); Okm{Xx  
C_n9T{k  
ni6{pK4Wqm  
//等待子线程结束 zSSB>D  
//int count = 0; @*Wh  
//是否结束while循环 .Y3pS/VI  
boolean breakWhile = false; z(fAnn T?  
+S R+x/?z  
z[cyA.  
while(!bStop) f~d d3m('  
{ ld^=#]g  
write_nPos(); \z$p%4`E@  
Utility.sleep(500); &Ibu>di4[  
breakWhile = true; Ka6,<C o  
|d*&y#kV  
hlJq-*6'  
for(int i=0;i<nStartPos.length;i++) rfgI$eu   
{ S6+y?,^  
if(!fileSplitterFetch.bDownOver) Wo7F  
{ >OG:vw)E  
breakWhile = false; phn9:{TI  
break; nD)K}4  
} P4F3Dc  
} {iv<w8CU)  
if(breakWhile) l411a9o  
break; O=$~O\}b  
9$Xu,y  
2Ri{bWi  
//count++; P#_sg0oJF  
//if(count>4) 9(5Oe H6o?  
// siteStop(); GHsilba  
} qnoNT%xazo  
s_> f5/i2  
CMCO}#  
System.err.println("文件下载结束!"); |R56ho5C  
} r4QxoaM  
catch(Exception e){e.printStackTrace ();} 3q'&j, ,^  
} rc/nFl 6#  
8:#rA*Y  
Ci<ATho  
//获得文件长度 }yJ$SR]t  
public long getFileSize() e89Xb;;w  
{ ]]&M@FM2z  
int nFileLength = -1; u6_@.a}  
try{ ~-dV^SO  
URL url = new URL(siteInfoBean.getSSiteURL()); &3$z4df  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); * =wYuJ#  
httpConnection.setRequestProperty("User-Agent","NetFox"); }t ;(VynV)  
V0%V5>  
 wAz&"rS  
int responseCode=httpConnection.getResponseCode(); qR8u$2}NY  
if(responseCode>=400) L}FO jrN  
{ HS.^y x  
processErrorCode(responseCode); >TP7 }u|  
return -2; //-2 represent access is error CXO2N1~(J  
} S=nP[s  
`"@g8PWe  
}Y*VAnY6;  
String sHeader; ' /$d0`3B>  
,N e;kI  
OI?K/rn  
for(int i=1;;i++) ph_4q@  
{ PIWux {  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); IR-dU<<9O  
//Utility.log(in.readLine()); svuq gSn  
sHeader=httpConnection.getHeaderFieldKey(i); w 1Ec_y{  
if(sHeader!=null) >^Yq|~[  
{ DF g,Xa#  
if(sHeader.equals("Content-Length")) h^*4}GU  
{ /MF! GM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); hTM[8 ~<^  
break; ~O]]N;>72"  
} V~hlq$jn<Y  
} PZm:T+5H  
else PNA\ TXT  
break; Y)$ ;Ax-D  
} T`9u!#mT=  
} VL/|tL>E^  
catch(IOException e){e.printStackTrace ();} mCWhUBghR  
catch(Exception e){e.printStackTrace ();} BA:yQ  
2PeR   
E^rbcGJ  
Utility.log(nFileLength); \/SQ,*O  
H{AMZyV0/d  
PI~1GyJr@;  
return nFileLength; [b/k3&O'  
} k $f Gom  
?0 m\(#  
v NeCpf  
//保存下载信息(文件指针位置) .!6>oL/iF  
private void write_nPos() tU^kQR!  
{ \y88d4zX  
try{ a3VM '  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 8NU`^L:1  
output.writeInt(nStartPos.length); *5wu   
for(int i=0;i<nStartPos.length;i++) uu/+.9  
{ d @*GUmJ  
// output.writeLong(nPos); [F*4EGB  
output.writeLong(fileSplitterFetch.nStartPos); [ G e=kFB  
output.writeLong(fileSplitterFetch.nEndPos); -PnyZ2'Z  
} Wfz\ `y  
output.close(); gxT4PQDy  
} s%!`kWVJ.  
catch(IOException e){e.printStackTrace ();} /%I7Vc  
catch(Exception e){e.printStackTrace ();} N~?{UOZd  
} LFZ iPu  
GCttXAto  
=L5GhA~  
//读取保存的下载信息(文件指针位置) `g_"GE  
private void read_nPos() p)=~% 7DV  
{ YqV8D&I  
try{ 4:sjH.u<  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); HeK h>  
int nCount = input.readInt(); 6SC,;p=  
nStartPos = new long[nCount]; ZZj~GQL(S  
nEndPos = new long[nCount]; a2f^x@0k  
for(int i=0;i<nStartPos.length;i++) Y9=(zOqv  
{ 6MG9a>=  
nStartPos = input.readLong(); {0@& OO:w  
nEndPos = input.readLong(); +@Ad1fJi  
} Pa^A$fy\  
input.close(); |w*R8ro_  
} H Y ynMP  
catch(IOException e){e.printStackTrace ();} g'l?~s`SB  
catch(Exception e){e.printStackTrace ();} DS2)@  
} 7P B)'Wl"6  
3s:%2%jVK  
+'G0{;b  
private void processErrorCode(int nErrorCode) H3H_u4_?SE  
{  x-'~Bu  
System.err.println("Error Code : " + nErrorCode); XG@`ZJhU6  
} J@ L9p46,  
Dl&GJ`&:p  
<X_!x_x  
//停止文件下载 !~ZP{IXyo  
public void siteStop() <N(oDaU  
{ axk"^gps  
bStop = true; s 1ge0~p3  
for(int i=0;i<nStartPos.length;i++) a P&D9%5  
fileSplitterFetch.splitterStop(); }6-ZE9H-v  
ow/57P  
XYH|;P6K  
} hAqg Iu*  
} >|o_wO  
//负责部分文件的抓取 phYDs9-K  
**FileSplitterFetch.java /U$8TT8+-  
*/ 45@]:2j  
package NetFox; 5y} v{Ijt  
!$g+F(:(c  
0fs$#j  
import java.io.*; >qo~d?+  
import java.net.*; = pIy  
hKlZi!4J  
` r']^ ,  
public class FileSplitterFetch extends Thread { Ao7`G':  
aVe/ gE  
b}G24{  
String sURL; //File URL 3I|3wQ&#(  
long nStartPos; //File Snippet Start Position }sxn72,  
long nEndPos; //File Snippet End Position {C^@Q"I  
int nThreadID; //Thread's ID FZH\Q~IUV  
boolean bDownOver = false; //Downing is over Bd3~EbFL  
boolean bStop = false; //Stop identical xAwf49N~  
FileAccessI fileAccessI = null; //File Access interface [`Cq\mI-W  
up%Z$"Y  
eV6o3u:9  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Hwm?#6\5  
{ jko"MfJ  
this.sURL = sURL; 2uk x (Z  
this.nStartPos = nStart; 7@PIM5h  
this.nEndPos = nEnd; [<wbbvXR  
nThreadID = id; RiO="tX'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 gcJF`H/iNK  
} -@IL"U6  
\Xt) E[  
Ze!92g  
public void run() Iia.k'N  
{ `!G7k  
while(nStartPos < nEndPos && !bStop) ^ie^VY($  
{ A%vsno!  
cgj.e  
On1v<SD$[  
try{ #vf_D?^  
URL url = new URL(sURL); l #@&~f[  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); z}.D" P+  
httpConnection.setRequestProperty("User-Agent","NetFox"); cX At :m  
String sProperty = "bytes="+nStartPos+"-"; *C,N'M<u  
httpConnection.setRequestProperty("RANGE",sProperty); /.=r>a }l  
Utility.log(sProperty);  yu ,h\  
&!y]:CC{  
mEQ!-p   
InputStream input = httpConnection.getInputStream(); {$^SP7qV#>  
//logResponseHead(httpConnection); !Zbesp KZ  
-)<m S  
2 Y|D'^  
byte[] b = new byte[1024]; ., :uZyG  
int nRead; _1jw=5^P\i  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) cCxi{a1uo  
{ >]}yXg=QK+  
nStartPos += fileAccessI.write(b,0,nRead); +#]|)V Z  
//if(nThreadID == 1) "]t>ZT:OJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IX?ZbtdX$`  
} }`9`JmNM  
C$#W{2x%6  
16@);Ot  
Utility.log("Thread " + nThreadID + " is over!"); w}M3x^9@  
bDownOver = true; ^C9x.4I$)  
//nPos = fileAccessI.write (b,0,nRead); G5{Ot>;*%  
} oA~4p(  
catch(Exception e){e.printStackTrace ();} `W[+%b  
} P 4;{jG  
} &.*uc|{  
B50 [O!  
(BERY  
//打印回应的头信息 k_3j '  
public void logResponseHead(HttpURLConnection con) qa}>i&uO  
{ 74zSP/G'  
for(int i=1;;i++) ;o$;Z4:.D  
{ MB* u-N0v  
String header=con.getHeaderFieldKey(i); 4&N$:j<  
if(header!=null) 6~W u`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); viuiqs5[Bi  
Utility.log(header+" : "+con.getHeaderField(header)); Y jup  
else JfTfAq]  
break; FD6v /Y  
}  q{X T  
} n9 fk,3  
"g `nsk  
(G8  
public void splitterStop() _=6OP8  
{ 3C"_$?y"  
bStop = true; vF>gU_gz.  
} Yg6I&#f7&  
+p?hGoF=  
'XTs -=  
} h#{T}[  
93I'cWN  
55hyV{L%  
/* GOW"o"S  
**FileAccess.java p`GWhI?  
*//文件访问(定位,写) ek[kq[U9  
package NetFox; Igjr~@ #  
import java.io.*; Ky&KF0  
uu>lDvR*  
] C,1%(  
public class FileAccessI implements Serializable{ 6wpU6NU  
b}%g}L D  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 0 [i+  
RandomAccessFile oSavedFile;  5T/J%  
long nPos; y[:q"BB3  
ny`(f,)u*  
&r:m&?!|VQ  
public FileAccessI() throws IOException /p$=Cg[K  
{ l<2oklo5  
this("",0); pb$fb  
} $WNG07]tU  
m;h<"]<  
6{7 3p@  
public FileAccessI(String sName,long nPos) throws IOException ycjJbL(.  
{ B+Q+0tw*i  
oSavedFile = new RandomAccessFile(sName,"rw"); =xBT>h;  
this.nPos = nPos; !~d'{sy6  
oSavedFile.seek(nPos); Yzd2G,kZ=  
} OMd# ^z  
=yh3Nd:u  
( 2zeG`  
public synchronized int write(byte[] b,int nStart,int nLen) &A"e,h(^  
{ p1 4d ,}4W  
int n = -1; b8HE."*t  
try{ U"B.:C2  
oSavedFile.write(b,nStart,nLen); t{=i=K 3  
n = nLen; M@~ o6^  
} 7O461$4v  
catch(IOException e) =z-5  
{  0dh#/  
e.printStackTrace (); A|C_np^z2  
} M*H< n*  
E&9!1!B  
leIy|K>\m  
return n; 1uC;$Aj6:  
} ^5>du~d  
" <*nZ~nE)  
8;8YA1@w  
} {,F/KL^u  
gr\@sx?b  
<p)Z/  
/* lO_c/o$  
**SiteInfoBean.java :Q=z=`*2w  
*/ UnjNR[=  
package NetFox;  6s5b$x  
,$BgR2^  
;24'f-Eri  
public class SiteInfoBean { -s89)lUkS  
j Ii[  
vu ?3$  
private String sSiteURL; //Site's URL U,38qKE  
private String sFilePath; //Saved File's Path a6qwL4  
private String sFileName; //Saved File's Name \2Xx%SX  
private int nSplitter; //Count of Splited Downloading File vQy$[D*  
08O7F  
3/l\ <{  
public SiteInfoBean() u6p5:oJj,  
{//nSplitter的缺省值为5 ,,}sK  
//default value of nSplitter is 5 ~BtKd*~*  
this("","","",5); s~)L_ p  
} f^u^-l  
J& )#G@fRX  
iz$FcA]  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) n_u`B|^Pj  
{ ]xI?,('_m  
sSiteURL= sURL; PC[cHgSYU  
sFilePath = sPath; gjQ=8&i  
sFileName = sName; vi<X3G6Xh  
this.nSplitter = nSpiltter; Fj,(_^  
/_HwifRQ  
d>;2,srUf  
} o|+E+l9\  
}R`Irxv4  
=Iy/cHK  
public String getSSiteURL() Dw*Arc+3V  
{ -}<d(c  
return sSiteURL; :;q>31:h  
} &q"'_4  
R|$[U  
xHm/^C&px  
public void setSSiteURL(String value) 0FTRm2(  
{ (GnVwJ<v9V  
sSiteURL = value; [\88@B=jXP  
} Et)9 20  
_ r~+p  
'HJ/2-=  
public String getSFilePath() T ^N L:78  
{ t18UDR{  
return sFilePath; v&e-`.xR  
} 6#fOCr;f7  
T7^ulG1'  
 YN4"O>  
public void setSFilePath(String value) \m%J`{Mt  
{ g%X&f_@  
sFilePath = value; O1|B3M[P  
} G&.d)NfE  
jT{f<P0  
.|U4N/XN%q  
public String getSFileName() L>0!B8X2  
{ kpl~/i`4  
return sFileName; Y:rJK|m  
} NoJUx['6  
I Jqv w  
6aRGG+H  
public void setSFileName(String value) P$6W`^D Z  
{ 2rF?Q?$,B  
sFileName = value; B'<!k7Ewy  
} \y[Bu^tk  
~."!l'a  
lfXH7jL2~  
public int getNSplitter() yLjV[ qP  
{ +g)_4fV0|  
return nSplitter; AS`2=w  
} lt{lHat1  
kV_#9z7%  
Ft)t`E'%j  
public void setNSplitter(int nCount) qo)Q}0  
{ S^|$23}  
nSplitter = nCount; ,Y$F7&  
} } /[_  
} z~BD(FDI  
k& WS$R?u  
]cn/(U`  
/* Fq vQk  
**Utility.java t8t}7XD   
*/ R:]/{b4Uq  
package NetFox; gW'P`Oxw  
uE"5cq'B/  
dFd lB `L  
public class Utility { $*YC7f  
u)tHOV>&  
8mk}nex  
public Utility() T"n>h  
{ TNyK@~#m  
oG+K '(BB  
AGl|>f)  
} zhuy ePn  
i/5y^  
//线程睡眠 g@<sU0B  
public static void sleep(int nSecond) wEBtre7  
{ zt-'SY  
try{ 9 %D$T'K  
Thread.sleep(nSecond); c9\B[@-q  
} os}b?I*K  
catch(Exception e) y T[Lzv#  
{ J"/ JRn  
e.printStackTrace (); \_lG#p|  
} |P^]@om  
} BjH~Ml2  
, D exJ1  
//日志 M4zX*&w.T  
public static void log(String sMsg) "L9C  
{ NE$VeW+@  
System.err.println(sMsg); ' 9IP;  
} zY]Bu-S3  
n^* >a  
@*CAn(@#N  
public static void log(int sMsg) ;[;)P tFz\  
{ LN@lrC7X  
System.err.println(sMsg); %T`4!:vy  
} q :TZ=bs^  
} fn1 ?Qp|  
H;b8I  
cYZwWMzp  
/* wrz+2EP`  
**TestMethod.java \Ku9"x  
*/ 'dmp4VT3  
package NetFox; "}S9`-Wd|  
[54@irH  
IW5*9)N?  
public class TestMethod { [>b  '}4  
2q`)GCES~  
+CsI,Uf4*  
public TestMethod() >v^2^$^u  
{ ///xx/weblogic60b2_win.exe Am>_4  
try{ s$f+/Hs  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); >E//pr)_Km  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); zkjPLeX  
SiteFileFetch fileFetch = new SiteFileFetch(bean); hknwis%y  
fileFetch.start(); fl} rz  
} E9yFREvQc  
catch(Exception e){e.printStackTrace ();}  6'RZ  
Z-N-9E  
$w|o@ Ml)  
} :SpG&\+  
Y&?|k'7  
UI|v/(_^F  
public static void main(String[] args) 03X<x|  
{ DZHrR:q?e  
new TestMethod(); t` }20=I+  
} 9F2w.(m  
} c*y$bf<  
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