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http断点续传简单实现(java)

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/* %plu]^Vy  
**SiteFileFetch.java %cO^:  
*/ ~ECIL7,  
package NetFox; t| PQ4g<  
import java.io.*; _"%hcCMw  
import java.net.*; |E?PQ?P  
 Zh  
"_^vQ1M]Z  
public class SiteFileFetch extends Thread { ^%n]_[RUn4  
9| g]M:{  
4bs<j  
SiteInfoBean siteInfoBean = null; //文件信息Bean VQ"Z3L3-4  
long[] nStartPos; //开始位置 ~] &yHzp2  
long[] nEndPos; //结束位置 oyT`AYa  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 FMOO  
long nFileLength; //文件长度 H@xHkqan  
boolean bFirst = true; //是否第一次取文件 XL3m#zW&  
boolean bStop = false; //停止标志 T>hrKn.!D:  
File tmpFile; //文件下载的临时信息 c>Tf@A og>  
DataOutputStream output; //输出到文件的输出流 U)[LKO1  
kzk8b?rOA  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) nR]*RIp5  
public SiteFileFetch(SiteInfoBean bean) throws IOException .C\2f+(U  
{ AQ&vq$  
siteInfoBean = bean; o:'@|(&<  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); vM'!WVs  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ds9U9t  
if(tmpFile.exists ()) Z9G4in8  
{ E~@&&d U8  
bFirst = false; \G#_z|'dN  
read_nPos(); ~GE|,Np  
} -5oYGLS$y3  
else [_eT{v2B4  
{ 7Ll? #eun  
nStartPos = new long[bean.getNSplitter()]; |:.s6a#(  
nEndPos = new long[bean.getNSplitter()]; ZZw2m@T>  
} D<hX%VJ%M  
znB+RiV8  
O>N/6Z  
w&@zJ[  
} @SH[<c  
1s~rWnhVv  
#zv&h`gY  
public void run() e"UXG\8D  
{ g:O/~L0Xb  
//获得文件长度 vz(=3C[  
//分割文件 ow  
//实例FileSplitterFetch =), O;M  
//启动FileSplitterFetch线程 VX*+:  
//等待子线程返回 8[.&ca/[  
try{ NT2XG& $W>  
if(bFirst) Nd]RbX  
{ x ;~;Ah.p  
nFileLength = getFileSize(); ]cv/dY#  
if(nFileLength == -1) pP#D*hiP-g  
{ 7Vk9{x$z  
System.err.println("File Length is not known!"); BL~#-Mm<|l  
} QW'*^^  
else if(nFileLength == -2) ^I|i9MH  
{ =`*@OJHH  
System.err.println("File is not access!"); l-cBN^^  
} 0i"2s}^+_  
else KWeE!f 7G  
{ [NJ2rQ/w7  
for(int i=0;i<nStartPos.length;i++) -[J4nN&N  
{ /NjBC[P  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); iITMBS`}  
} $IS!GS&:  
for(int i=0;i<nEndPos.length-1;i++) R>Dr1fc}  
{ =>lX brJ  
nEndPos = nStartPos[i+1]; VxS3lR=  
} o=#ym4hJ%  
nEndPos[nEndPos.length-1] = nFileLength; bI3GI:hp  
} Tt9cX}&&  
} jz HWs  
~ES%=if~Y  
00'SceL=`  
//启动子线程 :/%Y"0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; /P-#y@I  
for(int i=0;i<nStartPos.length;i++) wfe4b  
{ VwRZgL  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 5!S#}=f=  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,;5%&T  
nStartPos,nEndPos,i); ,\X ! :y~  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1=5HQ~|[TO  
fileSplitterFetch.start(); 94et ]u%7  
} 6$:Q]zR#'H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `R xCs`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (J.Z+s$:2  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", fVgN8b|&'  
nEndPos = " + nFileLength); _ yJz:pa  
// fileSplitterFetch[nPos.length-1].start(); q]C_idK=  
ItvcN  
s3m \  
//等待子线程结束 V=5S=7 Z:  
//int count = 0; MRXw)NAw  
//是否结束while循环 J)y g<*/3  
boolean breakWhile = false; x7<NaMK\  
k!z<=WA  
lw gwdB  
while(!bStop) aNY-F)XWa  
{ rQlQ^W$=?  
write_nPos(); )eT>[['fm  
Utility.sleep(500); j0X^,ot@m  
breakWhile = true; M*qE)dZjS  
&4KUXn[F  
2A@oa9  
for(int i=0;i<nStartPos.length;i++) Lfcy#3!  
{ nA_'j l  
if(!fileSplitterFetch.bDownOver) )`{m |\b  
{ ub fh4  
breakWhile = false; _b/zBFa%  
break; TfkGkVR  
} -`{W~yz  
} iX{2U lF7  
if(breakWhile) vdvnwzp!l  
break; yA"?Hv\o;  
Yq51+\d  
B+~ /-3  
//count++; n.a2%,|v  
//if(count>4) r5UV BV8T  
// siteStop(); sRZ<c  
} &n_f.oUc  
axt;}8  
M^8zqAA  
System.err.println("文件下载结束!"); |>xuH#Q  
} "0Z /|&  
catch(Exception e){e.printStackTrace ();} / [49iIzC  
} ps:`rVQ7  
%Rf9 KQ  
1hCU"|VH:  
//获得文件长度 VVAcbAGJ  
public long getFileSize() KMkD6g  
{ l4+ `x[^  
int nFileLength = -1; Rh)XYCM  
try{ R31Z(vY  
URL url = new URL(siteInfoBean.getSSiteURL()); 5EVypw?]x  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W!\%v"  
httpConnection.setRequestProperty("User-Agent","NetFox"); \WTKw x  
]g;+7  
fU ;H  
int responseCode=httpConnection.getResponseCode(); <yEApWd;  
if(responseCode>=400) U`EOun ,  
{ W?aP%D"(i  
processErrorCode(responseCode); G8__6v~  
return -2; //-2 represent access is error |O>e=HC#q8  
} -hm/lxyU  
-(WRhBpw  
MK/8<i<.  
String sHeader; X\H P{$fY_  
;T0X7MNx  
z7:* ,X  
for(int i=1;;i++) /0gr?I1wr7  
{ vdgK3I  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); xFThs,w  
//Utility.log(in.readLine()); Z:AB (c  
sHeader=httpConnection.getHeaderFieldKey(i); \}.bTca  
if(sHeader!=null) V[*>}XQER  
{ {.e+?V2>_  
if(sHeader.equals("Content-Length")) hg0{x/Dgny  
{ 2 yANf  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .xT{Rz  
break; 4[kyzz x  
} DBaZcO(U  
} ]9w8[T:O  
else Cc{{9Ud  
break; LVdR,'lS  
} fB7Jx6   
} 2BF455e   
catch(IOException e){e.printStackTrace ();} 3J 5,V  
catch(Exception e){e.printStackTrace ();} s1::\&`za  
-?1R l:rM  
rA?< \*  
Utility.log(nFileLength); y5aPs z  
u0=&_Q(=  
d6[' [dG  
return nFileLength; P=<lY},  
} w[ 3a^  
6[R6P:v&'G  
EHhc2^e  
//保存下载信息(文件指针位置) w nQy   
private void write_nPos() GLZ*5kw  
{ EyU6^  
try{ i={4rZOD^  
output = new DataOutputStream(new FileOutputStream(tmpFile)); $")Gd@aR  
output.writeInt(nStartPos.length); Y7q Q` |  
for(int i=0;i<nStartPos.length;i++) "bRjY?D  
{ E24}?t^|  
// output.writeLong(nPos); (Ly^+Hjg  
output.writeLong(fileSplitterFetch.nStartPos); TTa3DbFp%  
output.writeLong(fileSplitterFetch.nEndPos); eE .wnn  
} ?Q"<AL>Z  
output.close(); "m6G;cv  
} \zk>cQ  
catch(IOException e){e.printStackTrace ();} +eH`mI0f  
catch(Exception e){e.printStackTrace ();} gq*W 0S  
} z(.,BB[  
-!5l4  
qj:[NPwaM  
//读取保存的下载信息(文件指针位置) K+M\E[1W  
private void read_nPos() `DSFaBj,  
{ XI$W  
try{ Uea2WJpX  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); baTd;`Pn  
int nCount = input.readInt(); 1~E4]Ef:W  
nStartPos = new long[nCount]; UfO='&U^  
nEndPos = new long[nCount]; V,c^Vq y  
for(int i=0;i<nStartPos.length;i++) _D{FQRU<YD  
{ EFI!b60mc  
nStartPos = input.readLong(); 1/ j >|  
nEndPos = input.readLong(); %q;y74  
} 6?.S-.Mr  
input.close(); />:$"+gKo  
} B+R|fQ  
catch(IOException e){e.printStackTrace ();} C{t}q*fG 5  
catch(Exception e){e.printStackTrace ();} q2`mu4B  
} rbv  
@~7au9.V=X  
@Q nKaZ8jW  
private void processErrorCode(int nErrorCode) * &#M`,#  
{ >Q"3dw  
System.err.println("Error Code : " + nErrorCode); ?kV_!2U)'K  
} K+L9cv4 |*  
[z7]@v6b  
-R];tpddR5  
//停止文件下载 fn7?g  
public void siteStop() OaoHN& "  
{ #^|2PFh5  
bStop = true; YB)I%5d;{  
for(int i=0;i<nStartPos.length;i++) kDQE*o  
fileSplitterFetch.splitterStop(); 9|@5eN:N  
##mBOdx  
5=9Eb  
} h5aPRPUg  
} `)w=@9B)"  
//负责部分文件的抓取 Abmi=]\bx  
**FileSplitterFetch.java 9]G~i`QQ  
*/ :]8A;`G}  
package NetFox; } 21!b :a  
vs$. i  
#-"C_~-MH  
import java.io.*; &h6 `hP_  
import java.net.*; !VudZ]Sg  
+>u 8r&Jw.  
5OFB[  
public class FileSplitterFetch extends Thread { KNP^k$=)3c  
$kR%G{j 4  
md\Vw?PkU  
String sURL; //File URL O_ $zK  
long nStartPos; //File Snippet Start Position r`+G9sj3U  
long nEndPos; //File Snippet End Position ]D2 d=\  
int nThreadID; //Thread's ID 4QiV@#o:  
boolean bDownOver = false; //Downing is over 1[a#blL6W  
boolean bStop = false; //Stop identical w; f LnEz_  
FileAccessI fileAccessI = null; //File Access interface *'{9(Oj  
zY4y]k8D*  
PCc{0Rp\vk  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException L0%W;m  
{ 4VsttT  
this.sURL = sURL; sVnpO$  
this.nStartPos = nStart; tgeXX1Eq!  
this.nEndPos = nEnd; ?4W6TSW-'  
nThreadID = id; t|UM2h  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 'auYmX  
} AuBBSk8($  
NVf_#p"h  
SU~ljAF4  
public void run() bNvc@oo  
{ f{(D+7e}  
while(nStartPos < nEndPos && !bStop) ~qA\u5sB9@  
{ zx?|5=+!  
IFF1wfC  
9!Fg1 h=  
try{ H$zDk  
URL url = new URL(sURL); !(j<Y0xo:  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); %wJ?+D/  
httpConnection.setRequestProperty("User-Agent","NetFox"); QbWeQ[V{  
String sProperty = "bytes="+nStartPos+"-"; G{a_\'7  
httpConnection.setRequestProperty("RANGE",sProperty); VZk;{  
Utility.log(sProperty); |B\76Nk  
`@<)#9'A  
uxW<Eh4H*  
InputStream input = httpConnection.getInputStream(); I]91{dq  
//logResponseHead(httpConnection); j#H&~f  
Qb86*  
%w3tzE1Hq  
byte[] b = new byte[1024]; 0v3 8LBH)  
int nRead; 5~i}!n  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) mw\Pv|  
{  ~>3#c#[  
nStartPos += fileAccessI.write(b,0,nRead); \LM{.g zT  
//if(nThreadID == 1) k& ]I;Aq  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 7VfPS5se  
} d}^hZ8k|  
Dv=pX.Z+  
<M,=( p{  
Utility.log("Thread " + nThreadID + " is over!"); ]L\]Ll;  
bDownOver = true; z{U^j:A  
//nPos = fileAccessI.write (b,0,nRead); X;dUlSi  
} v 5&8C  
catch(Exception e){e.printStackTrace ();} t"&qaG{  
} <EuS6Pg  
} t8~isuiK  
p$XvVzW#<  
B(R$5Xp  
//打印回应的头信息 Y0o{@)Y:  
public void logResponseHead(HttpURLConnection con) |Tk'H&  
{ :-T[)Q+-3  
for(int i=1;;i++) !z+'mF?V+X  
{ .fNLhyd  
String header=con.getHeaderFieldKey(i); ~<3J9\z1  
if(header!=null) BIjkW.uf  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); D [K!xq  
Utility.log(header+" : "+con.getHeaderField(header)); vyruUYFWe  
else #nS crs@  
break; 'RIx}vPf  
} (ZD~Q_O-  
} SA,+oq(  
E qt\It9  
7$JE+gL/7  
public void splitterStop() 6LzN#g  
{ ?; tz  
bStop = true; r]bG,?|  
} '.t{\  
Pt7yYl&n7^  
I=4G+h5p  
} qfgw^2aUa  
<e$%m(]  
3 E!F8GZ  
/* i [2bz+Z?  
**FileAccess.java ?H21Ru>:*  
*//文件访问(定位,写) b'(Hwc\ t  
package NetFox; /wJocx]vQ  
import java.io.*; rTA#4.*&  
8} |!p>  
a}kPc}n\  
public class FileAccessI implements Serializable{ d@+u&xrd  
RWXN  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 lxtt+R  
RandomAccessFile oSavedFile; ?q}:ojrs1  
long nPos; '17V7A/t  
~{{@m]P  
vk|xYDD  
public FileAccessI() throws IOException ME'LZ"VT  
{ 94u~:'t>V  
this("",0); FLaj|Z~#)  
} JYa3xeC;  
8>!-|VSn  
p)*x7~3e  
public FileAccessI(String sName,long nPos) throws IOException | =tGrHL  
{ FtybF  
oSavedFile = new RandomAccessFile(sName,"rw"); }n?D#Pk,  
this.nPos = nPos; (Iv*sd *  
oSavedFile.seek(nPos); 9]^NAlno  
} iq3TP5%i  
dp*E#XCr1  
ZEG~ek=jM  
public synchronized int write(byte[] b,int nStart,int nLen) Vu Ey`c  
{ w9CX5Fg  
int n = -1; *:Y9&s^6j  
try{ sn yA  
oSavedFile.write(b,nStart,nLen); 9Q&]5| x  
n = nLen; gmtS3,  
} C@9K`N[*  
catch(IOException e) t7,**$ST  
{ :<,tGYg/!  
e.printStackTrace (); OZ2faf  
} z]1g;j  
>9X+\eg-  
LN=#&7=$c  
return n; ez[$;>  
} ])vqXjN6"  
qex::Qf  
M#xol/)h  
} @Qd5a(5WM  
FES0lw{G#  
~?KbpB|  
/* X^d}eWP`I  
**SiteInfoBean.java s,7 OoLE  
*/ be>KG ZU0  
package NetFox; ?)e6:T(  
L^L.;1  
\;!g@?CA  
public class SiteInfoBean { UX)QdT45Mh  
%TzdpQp"  
G:Nwi=vN  
private String sSiteURL; //Site's URL 9zaSA,}  
private String sFilePath; //Saved File's Path eyG[1EEU  
private String sFileName; //Saved File's Name 10m`LG  
private int nSplitter; //Count of Splited Downloading File 3+V.9TL'a  
^aY,Wq  
^fti<Lw5  
public SiteInfoBean() slV]CXW)t  
{//nSplitter的缺省值为5 ^1X 6DH`  
//default value of nSplitter is 5 (^^}Ke{J  
this("","","",5); ccgV-'IG9  
} T,v5cc:nO  
^P owL:  
j15t8du&O  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) /mnV$+BE  
{ 9+:<RFJ  
sSiteURL= sURL; Zu/1:8x  
sFilePath = sPath; ]!cLFXa  
sFileName = sName; .a}!!\@  
this.nSplitter = nSpiltter; je=XZ's,i~  
Q6fPqEX=  
1yjP`N  
} d&%}u1 .  
PAv<J<d  
l1]'3]P(  
public String getSSiteURL() '#CYw=S+  
{ Z8WBOf*~e  
return sSiteURL; qj,^"rp1:  
} DcEGIaW  
64f6D"."  
kj'  
public void setSSiteURL(String value) =p#:v  
{ Q=#!wWVP  
sSiteURL = value; z A@w[.  
} M.KXDD#O  
$ZnVs@:S  
&F|Wk,y  
public String getSFilePath() YG>6;g)Zm  
{ \$2zF8  
return sFilePath; #\MkbZc d  
} E# *`u  
{)& b6}2h  
QykHB k  
public void setSFilePath(String value) 4 zipgw  
{ 5z"[{ #/  
sFilePath = value; 'z">4{5  
}  fG|+ !  
k:CSH{s5{  
;;n=(cM|z  
public String getSFileName() (.~'\@  
{ "Kf4v|6;  
return sFileName; ,pVq/1  
} :w:ql/?X  
~)]n67Or~  
:*)b<:4  
public void setSFileName(String value) EtA,ow  
{ \`WAG>'l5  
sFileName = value; 7kQ,D,c'  
} fh@/fd  
kud2O>>  
^j]"5@f  
public int getNSplitter() t 2&}  
{ ]`eJSk.  
return nSplitter; X*rB`M7,  
} "gq _^&  
LQ4F/[1}  
{aWfD XB1  
public void setNSplitter(int nCount) B-aJn8>/  
{ Aq{7WA  
nSplitter = nCount; LrnE6 U9  
} <^B!.zQ  
} 'pl){aL`@u  
K@;ls  
f{f|frs  
/* }7/Ob)O  
**Utility.java KPs @v@5M  
*/ 1A/li%  
package NetFox; =!PUKa3f<  
?iNihE  
s&Qil07 Vl  
public class Utility { `jH0FJQ  
({p @Ay  
"AMsBvzgo  
public Utility() =/F\_/Xw  
{ D_Cd^;b  
T|lyjX$Q]9  
K6z-brvw "  
} *saO~.-;4  
 S]&7  
//线程睡眠 ^tFgkzXm  
public static void sleep(int nSecond) #ui7YUR=2  
{ 3 Ho<4_I,  
try{ ' C|yUsBC  
Thread.sleep(nSecond); z3p #`  
} oi}\;TG  
catch(Exception e) OL)M`eVQ'  
{ 3ZU<u;  
e.printStackTrace (); ;l'kPUv([  
} s7TV@Y)  
} 9:jZ3U  
7U{g'<  
//日志 80qe5WC.2u  
public static void log(String sMsg) ;R.l?Bg  
{ 3RTraF  
System.err.println(sMsg); nFfwVqV  
} gAgP("  
d ;W(Vm6  
,zY!EHpx  
public static void log(int sMsg) kKg%[zXS  
{ ^atBf![  
System.err.println(sMsg); )q+9_KU q  
} x9!vtrM\Zr  
} /K]<7  
4?{e?5)  
L E>A|M$X  
/* +e%U6&l{  
**TestMethod.java L'Fy\K\  
*/ *m[ow s  
package NetFox; enGjom  
o-jF?9m  
;eRYgC  
public class TestMethod { e-#!3j!'  
Zu/}TS9bi  
@n##.th  
public TestMethod() ~y(- j[  
{ ///xx/weblogic60b2_win.exe ,,>b=r_r&  
try{ )} H46  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P]G`Y>#$r  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 0-W{(xy@4  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +L8 6 w7  
fileFetch.start(); S:En9E  
} Bld$<uU  
catch(Exception e){e.printStackTrace ();} uI I:Y{G  
oZV=vg5Dq  
a!>yX ex  
} 2I#4jy/g  
u9*}@{,  
H0 YxPk)  
public static void main(String[] args) XKU+'Tz  
{ < g<Lf[n$  
new TestMethod(); siHS@S  
} ,HxsU,xiG  
} 7lvUIc?krW  
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