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http断点续传简单实现(java)

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/* b:Kw_Q  
**SiteFileFetch.java 1:zu$|%7  
*/ /dt!J `:  
package NetFox; L5 9oh  
import java.io.*; |ozoc"'  
import java.net.*; 6;frIl;  
z L'IN)7MU  
%D(prA_w  
public class SiteFileFetch extends Thread { ;&6PL]/d  
;-pvc<_c<  
wp.e3l  
SiteInfoBean siteInfoBean = null; //文件信息Bean 9}cuAVI  
long[] nStartPos; //开始位置 /}`/i(k  
long[] nEndPos; //结束位置 3D{4vMm X  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ^:DhHqvK  
long nFileLength; //文件长度 Pmlgh&Z  
boolean bFirst = true; //是否第一次取文件 QX.6~*m1  
boolean bStop = false; //停止标志 %K'*P56  
File tmpFile; //文件下载的临时信息 C'/M/|=Q#  
DataOutputStream output; //输出到文件的输出流 _SC  
?vn 0%e868  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) i `QK'=h[  
public SiteFileFetch(SiteInfoBean bean) throws IOException C2rj]t  
{ /lB0>Us  
siteInfoBean = bean; ynZ[c8.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;K\N  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); C6UMc} 9h  
if(tmpFile.exists ()) >Y-TwD aE  
{ }u_EXP8M  
bFirst = false; Pgw%SMEp  
read_nPos(); RyOT[J  
} b2X'AHK S  
else P^3m:bE]  
{ \1mM5r~  
nStartPos = new long[bean.getNSplitter()]; ~Oq,[,W  
nEndPos = new long[bean.getNSplitter()]; R``V Q  
} 9LO.8Jy  
} ndvV~*1  
K= Z]#bm  
0*Km}?;0-  
} Uc_`Eh3y  
Fy@#r+PgWp  
nj^q@h  
public void run() %Mng8r  
{ *76viqY;dE  
//获得文件长度 _lPl)8k  
//分割文件 ?3, 64[  
//实例FileSplitterFetch Dg>'5`&  
//启动FileSplitterFetch线程 4ZJT[zi  
//等待子线程返回 )yNw2+ ~5  
try{ >}DjHLTW\  
if(bFirst) ~"q,<t  
{ 37 O#aJ,K  
nFileLength = getFileSize(); Uty(sDtu  
if(nFileLength == -1) q"+ q  
{ `+hy#1]  
System.err.println("File Length is not known!"); Md>f  
} `}9 1S  
else if(nFileLength == -2) ra%R:xX  
{ w <#*O:  
System.err.println("File is not access!"); ECS<l*i57&  
} ,/?%y\:J  
else "T{~,'T  
{ adO!Gs9f?  
for(int i=0;i<nStartPos.length;i++) I,<>%Z|'  
{ \'??  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Jn<e"  
} LPapD@Z  
for(int i=0;i<nEndPos.length-1;i++) t}XB|h  
{ !q-:rW? c  
nEndPos = nStartPos[i+1]; 762o~vY6$  
} yxCM l.  
nEndPos[nEndPos.length-1] = nFileLength; n4vXm  
} 3j+=3n,  
} y4/>Ol]  
t?9 ;cS4  
i_0 ,BV C  
//启动子线程 WAwfL?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9xK4!~5V  
for(int i=0;i<nStartPos.length;i++) qX p,d  
{ 1akD]Z  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YMj7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), )&Kn (l)  
nStartPos,nEndPos,i); +e0dV_T_>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); | or 8d>,  
fileSplitterFetch.start(); 7~kpRa@\P  
} I|F~HUzA"  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Jcalf{W6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); J-, H6u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ''(fH$pY  
nEndPos = " + nFileLength); v?YdLR  
// fileSplitterFetch[nPos.length-1].start(); e7XsyL'|p  
|D;"D  
ZSF=  
//等待子线程结束 hy$MV3LP  
//int count = 0; z;bH<cQ  
//是否结束while循环 ~'^!udF-  
boolean breakWhile = false; :7$\X[  
^_*jp[!`b$  
SRt$4EL21  
while(!bStop) ZL-uwI!`D  
{ vh|Tb5W<  
write_nPos(); 5W[3_P+  
Utility.sleep(500); IqhICC1V-  
breakWhile = true; 7 >PF~=  
4f4 i1i:  
O1x0[sy  
for(int i=0;i<nStartPos.length;i++) Ad]<e?oN=  
{ -5V)q.Og  
if(!fileSplitterFetch.bDownOver) T6h;Y  
{ 8 zQ_xE  
breakWhile = false; A*7Io4e!  
break; L.09\1?.n  
} W{fULl  
} zG-_!FIn  
if(breakWhile) 8!u/   
break; tC2 )j7@  
Y )u_nn'[  
?%\mQmjas  
//count++; 9RG\UbX)^|  
//if(count>4) vp\PYg;x  
// siteStop(); ! Q|J']|  
} JqI6k6~Q^  
v!<PDw2'  
hmK8j l<6  
System.err.println("文件下载结束!"); j+_S$T8w  
} \6`v.B&v  
catch(Exception e){e.printStackTrace ();} 2 ) TG  
} -"~L2f"?  
j~,h )C/ v  
GB&Nt{  
//获得文件长度 4R& *&GZ#  
public long getFileSize() )u39}dpeu  
{ <@u0.-]  
int nFileLength = -1; 5TXg;v#Z  
try{ KY4d+~2  
URL url = new URL(siteInfoBean.getSSiteURL()); _MM   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `4VO&lRm  
httpConnection.setRequestProperty("User-Agent","NetFox"); BN+V,W  
!Oeq G  
N4I^.k<-A  
int responseCode=httpConnection.getResponseCode(); wzD\8_;6N  
if(responseCode>=400) 2}^+ ]5  
{ JQ*D   
processErrorCode(responseCode); GN\8![J  
return -2; //-2 represent access is error -'80>[}q/  
} 7<h.KZPc  
)-0[ra]  
eQ$N:]  
String sHeader; :fxWz%t  
mWNR(()v  
90Xt_$_}s  
for(int i=1;;i++) CdX`PQ  
{ @4;HC=~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); _FL<egK  
//Utility.log(in.readLine()); "Jb3&qdU  
sHeader=httpConnection.getHeaderFieldKey(i); LWD.  
if(sHeader!=null) V-[2jC{  
{ ^ [ET&"  
if(sHeader.equals("Content-Length")) q&u$0XmV  
{  qovQ9O  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); (l Lu?NpIi  
break; ^fkCyE;=  
} M6# \na  
} )yHJ[  
else @(Z( /P;:  
break; E::L?#V  
} m])Lw@#9W  
} joe9.{  
catch(IOException e){e.printStackTrace ();} 2*+ 3Rr J  
catch(Exception e){e.printStackTrace ();} LFCTr/,  
2bWUa~%B  
-r!42`S  
Utility.log(nFileLength); + Qt[1Xq  
]x1p!TSU  
,,S9$@R  
return nFileLength; K6E}";;  
} <#>Oy&E  
"cwR^DoD&  
rxQ<4  
//保存下载信息(文件指针位置) ICk(z~D~  
private void write_nPos() zEy&4Kl{+  
{ _Aa[?2 O  
try{ iu +3,]7Fm  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3a'q`.L  
output.writeInt(nStartPos.length); QO@6VY@  
for(int i=0;i<nStartPos.length;i++)  for {  
{ u2 7S %2P  
// output.writeLong(nPos); 5Yl6?  
output.writeLong(fileSplitterFetch.nStartPos); QW2?n`Fa9-  
output.writeLong(fileSplitterFetch.nEndPos); |Td_S|:d  
} n<E.Em1  
output.close(); pL~=Z?(B  
} ^b=XV&{q  
catch(IOException e){e.printStackTrace ();} sD2 ^_w6j  
catch(Exception e){e.printStackTrace ();} =qw &dwIQ  
} S9J5(lYv~N  
=:4?>2)  
.vK.XFZ8R  
//读取保存的下载信息(文件指针位置) qh$X^%g  
private void read_nPos() c )03Ms4 D  
{ _D-5}a"  
try{ eO'xkm  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); )`<6taKx@n  
int nCount = input.readInt(); }S,-uggz  
nStartPos = new long[nCount]; #'C/Gya  
nEndPos = new long[nCount]; ~^x-ym5  
for(int i=0;i<nStartPos.length;i++) 2\5cjdy  
{ 8hZwQ[hr  
nStartPos = input.readLong(); q8/ihA6:  
nEndPos = input.readLong(); <^Nk.E  
} R3?:\d{  
input.close(); H-Pq!9[DB  
} AQe!Sqg'  
catch(IOException e){e.printStackTrace ();} 2 % %|fU9  
catch(Exception e){e.printStackTrace ();} l]$40 j  
} } %+qP +O\  
U%q:^S%#eG  
WV2~(/hX&  
private void processErrorCode(int nErrorCode) Wk}D]o0^@  
{ O] H=s  
System.err.println("Error Code : " + nErrorCode); E`tQe5K  
} c#  xO<  
E3f9<hm   
AVv#\JrRW  
//停止文件下载 TMww  
public void siteStop() { UOhVJy  
{ ywEDy|Wn$~  
bStop = true; QF.3c6O@  
for(int i=0;i<nStartPos.length;i++) _W|R;Cz]  
fileSplitterFetch.splitterStop(); o!utZmk$  
6|^0_6_  
%9X{{_  
} /$Z m~Mp  
} \6:>{0\  
//负责部分文件的抓取 6b<+8w  
**FileSplitterFetch.java C3)|<E  
*/ "XhOsMJ  
package NetFox; *> KHRR<N  
5q Rc4d'  
r4?b0&Xq  
import java.io.*; ]26mB  
import java.net.*; <m0{'xw  
Oqmg;\pm  
U*qNix  
public class FileSplitterFetch extends Thread { sMm/4AY]  
TP{Gt.e  
T(V8; !  
String sURL; //File URL (z2Z)_6L*L  
long nStartPos; //File Snippet Start Position d=y0yq{L  
long nEndPos; //File Snippet End Position %[ /<+  
int nThreadID; //Thread's ID f>z`i\1oO  
boolean bDownOver = false; //Downing is over 5oJ Dux }  
boolean bStop = false; //Stop identical ^df x~C  
FileAccessI fileAccessI = null; //File Access interface G?/c/rG  
xr.XU'  
YjLe(+ WQ  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException q@kOTkHv)  
{ /EU ; ?O  
this.sURL = sURL; .=XD)>$  
this.nStartPos = nStart; l{5O5%\,  
this.nEndPos = nEnd; 4\6: \  
nThreadID = id; LwOJ |jA(,  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 > :Ze4}(  
} ej52AK7  
jo_ sAb  
<0 uOq  
public void run() Qn.[{rw  
{ Me/\z^pF  
while(nStartPos < nEndPos && !bStop) ] H&c'  
{ !)c=1EX]"  
-CD\+d  "  
+j[`,5oS  
try{ :Q-oV8t{  
URL url = new URL(sURL); d0 -~| `5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @]=f?+y[ 2  
httpConnection.setRequestProperty("User-Agent","NetFox"); HE;V zR  
String sProperty = "bytes="+nStartPos+"-"; ZXt?[Ll  
httpConnection.setRequestProperty("RANGE",sProperty); :}9j^}"c3  
Utility.log(sProperty); o@/xPo|  
w<t,j~ Pr#  
qVBL>9O*.  
InputStream input = httpConnection.getInputStream(); j[XYj6*d  
//logResponseHead(httpConnection); %8w9E=  
P+Z\3re  
"- eZZEl(  
byte[] b = new byte[1024]; *vnXlV4L  
int nRead; xmr|'}Pt[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [M:S`{SbY  
{ :c7CiP  
nStartPos += fileAccessI.write(b,0,nRead); ?2ItB`<(  
//if(nThreadID == 1) ArzDI{1  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @B`Md3$7  
} QU/3X 1W  
O?ktWHUx  
=& -[TPW  
Utility.log("Thread " + nThreadID + " is over!"); Y)M8zi>b  
bDownOver = true; T'1gy}  
//nPos = fileAccessI.write (b,0,nRead); kH?#B%N5  
} 6Cc7ejt|u  
catch(Exception e){e.printStackTrace ();} DMZ`Sx  
} MEq"}zrh  
} <m-.aK{9  
Y"!uU.=xJ  
L.B~ax.|Z  
//打印回应的头信息 ll<mE,  
public void logResponseHead(HttpURLConnection con) |0 !I5|<k  
{ <o0~H  
for(int i=1;;i++) )acV-+{  
{ \c7>:DH  
String header=con.getHeaderFieldKey(i); tln1eN((q  
if(header!=null) ."mlSW"Wm  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ai;\@$ cq  
Utility.log(header+" : "+con.getHeaderField(header)); 6>DLp}d  
else Qhy#r  
break; jN/ j\x'  
} =;{^" #r\  
} r{[OJc!  
n &}s-`D  
qn"K9k  
public void splitterStop() M{G xjmdx  
{ sLns3&n2  
bStop = true; o8z)nOTO;  
} q`Q}yE> 9  
EJm4xkYLj1  
E4HU 'y~  
} &q>zR6jne  
Q$a  
^8K/xo-  
/* H+l,)Se  
**FileAccess.java  t;47(U  
*//文件访问(定位,写) Eg8i _s~:  
package NetFox; z%:&#1)  
import java.io.*; uLVBM]Qj  
4tJa-7  
5=Lq=,K$  
public class FileAccessI implements Serializable{ [e e30ELn  
mX\ ;oV!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 B9M>e'H%<  
RandomAccessFile oSavedFile; nPA@h  
long nPos; ]b}B2F'n  
&erm`Ho  
DDw''  
public FileAccessI() throws IOException (-"`,8K 2}  
{ pbn\9C/  
this("",0); y=H@6$2EQ  
} >n$ !<  
&mkpJF/  
;/sHWI f+Z  
public FileAccessI(String sName,long nPos) throws IOException DWf$X1M  
{ O4Dr ]Xc]  
oSavedFile = new RandomAccessFile(sName,"rw"); ^oeJKjJ  
this.nPos = nPos; 4~|<` vqN  
oSavedFile.seek(nPos); x-_vl 9P)  
} cm@;*  
"2hh-L7ql  
u \g ,.C0  
public synchronized int write(byte[] b,int nStart,int nLen) m ,tXE%l  
{ 7NF/]y4w  
int n = -1; J?Iq9f  
try{ L`3n2DEBf  
oSavedFile.write(b,nStart,nLen); 5 9 -!6;T  
n = nLen; O#_x)13  
} ([LIjaoi  
catch(IOException e) b{&FuvQg2  
{ '3;v] L?G  
e.printStackTrace (); 2 ZG@!Y|  
} <Ar$v'W=F{  
+)/ Uu3"=  
{#hVD4$b  
return n; E%3TP_B3  
} 7z'h a?  
Ade }g'  
5w<A;f  
} Yc#IFmC}  
UI?=]"  
J@#?@0]F  
/* c`kQvXx  
**SiteInfoBean.java LWmB, Zf/  
*/ 4v.d-^  
package NetFox; 3 ^}A %-bS  
fx?$9(r,  
(bm;*2  
public class SiteInfoBean { !j^&gRH  
bFGDgwe z  
Qv{,wytyO  
private String sSiteURL; //Site's URL >*qQ+_  
private String sFilePath; //Saved File's Path m*n5zi|O  
private String sFileName; //Saved File's Name @Icq1zb] y  
private int nSplitter; //Count of Splited Downloading File {fz$Z!8-  
`W5-.Tv  
h;M3yTM-  
public SiteInfoBean() oU+F3b}5p  
{//nSplitter的缺省值为5 eegx'VSX4  
//default value of nSplitter is 5 OO-k|\{ |  
this("","","",5); vsMmCd)7U  
}  (^: p  
2@Lb foA  
 y4jU{,  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 8ws$k\>  
{ 92[a; a  
sSiteURL= sURL; xJhU<q~?  
sFilePath = sPath; `;%ZN  
sFileName = sName; 8<dOMp;}r  
this.nSplitter = nSpiltter; f_\_9o"l  
GP,<`l&  
I1=(. *B}  
} ;=~Xr"(/z  
~`cwG` 'N  
S!Jh2tsg`-  
public String getSSiteURL() #R5U   
{ ,=PKd&  
return sSiteURL; -5Utl os  
} 0Y?H0  
T>d.#  
1FERmf? ?d  
public void setSSiteURL(String value) (! KG)!  
{ ;ojiJ ?jU  
sSiteURL = value; ]<trA$ 0  
} ls|LCQPx  
iHBB,x  
74J@F2g}?  
public String getSFilePath() "/+zMLY  
{ 2qU&l|>  
return sFilePath; s~L</Xvo  
} 7P**:b  
<$i4?)f(  
<bUe/m  
public void setSFilePath(String value) j^SZnMQf  
{ r<R4 1Fz  
sFilePath = value; w{,4rk;Hr  
} }31Z X  
Mr3-q  
MC!ZX)mF  
public String getSFileName() UY>v"M  
{ @,OT/egF4:  
return sFileName; C"eXs#A  
} QMp r v*i  
]r/^9XaqtA  
d7Ro}>lp  
public void setSFileName(String value) wij,N(,H  
{ GjT#%GBF  
sFileName = value; FN87^.^2S  
} *@S@x{{s  
^v ni&sJ  
wEEn?  
public int getNSplitter() 0^l%j8/  
{ L^0v\  
return nSplitter; +t!S'|C  
} ?S[Y:<R{:  
QU5Sy oL[  
>fs2kha  
public void setNSplitter(int nCount) iEHh{H(  
{ ERz;H!pU8  
nSplitter = nCount; (-^bj  
} gS9>N/b|  
} gK1g]Tc@G  
!iu5OX7K|  
|+f-h,  
/* 4< S'  
**Utility.java _elX<o4  
*/ x\\7G^$<h  
package NetFox; >lzA]aM$c  
+RDJY(Y$  
:0~QRc-u  
public class Utility { \;9W.d1iU  
u=NG6 G  
-,# +`>w  
public Utility() + ,4" u  
{ e@]-D FG  
ff2d @P,!  
%,V YiW0  
} E`;;&V q-  
5J.0&Dda  
//线程睡眠 ~^US/"  
public static void sleep(int nSecond) &"E lm  
{ DSyXr~p8  
try{ X_TiqV  
Thread.sleep(nSecond); >FF5x#^&c  
} i'HQQWd  
catch(Exception e) QWO]`q`|  
{ w4};q%OBj  
e.printStackTrace (); 1,t)3;o$  
} _M5%V>HO  
} YZwaD b  
J7$_VP  
//日志 n! h7   
public static void log(String sMsg) S-F o  
{ 4Y ROB912  
System.err.println(sMsg); <PD?f/4 /  
} {E_{JB~`  
2KJ1V+g@a6  
`N8 7 h"  
public static void log(int sMsg) 5 t{ja  
{ 5f7zk  
System.err.println(sMsg); a:Q[gF8>  
} Z|m`7xeCy  
} \=2m7v#E  
Wch~ Yb  
CXaWgxlK:a  
/* 9U_ks[Qa  
**TestMethod.java iLX_T]1  
*/ eEw.'B  
package NetFox; Mt>oI SN&d  
dJuD|9R  
JAb6zpP  
public class TestMethod { J./d!an  
~}9PuYaD@  
#2p#VQh  
public TestMethod() lFG9=Wf  
{ ///xx/weblogic60b2_win.exe Y%`SHe7M  
try{ tjnPyaJEl  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 4`v!Z#e/aX  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); LDj<?'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); oOU1{[  
fileFetch.start(); hlbvt-C?}"  
} WrGK\Vw[  
catch(Exception e){e.printStackTrace ();} jA(vTR.`  
Ty4S~ClO#'  
WCq /c6 D  
} b~Y%gC)FR  
4vZ4/#(x  
N3A<:%s  
public static void main(String[] args) L EWhb!U  
{ `#s#it'y  
new TestMethod(); /Ft:ffR|R  
} OYL]j{  
} E#%}ZY  
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