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http断点续传简单实现(java)

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/* Ox}a\B8  
**SiteFileFetch.java ~ZZJ/Cu  
*/ hYU4%"X  
package NetFox; Y|N.R(sAs&  
import java.io.*; 8YwSaBwO  
import java.net.*; p& +w  
Tn(c%ytN  
iP+3)  
public class SiteFileFetch extends Thread { VW *d*!  
n~G-X  
A&($X)t  
SiteInfoBean siteInfoBean = null; //文件信息Bean J+=+0{}  
long[] nStartPos; //开始位置 guWX$C-+1  
long[] nEndPos; //结束位置 _16IP  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "o>gX'm*  
long nFileLength; //文件长度 56^#x  
boolean bFirst = true; //是否第一次取文件 !Di*y$`}b  
boolean bStop = false; //停止标志  wA7^   
File tmpFile; //文件下载的临时信息 %L eZd}v  
DataOutputStream output; //输出到文件的输出流 ])uhm)U@  
%t J@)  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) !O*uQB  
public SiteFileFetch(SiteInfoBean bean) throws IOException xE%sPWbj  
{ Vrx3%_NkQ  
siteInfoBean = bean; $WHmG!)*  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); B0eKj=y;  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); #a=~a=c(^  
if(tmpFile.exists ()) Z2hIoCT  
{ S|v")6  
bFirst = false; {/PiX1mn  
read_nPos(); e95@4f^K2  
} kxVR#:  
else 0dKi25J  
{ R`!'c(V  
nStartPos = new long[bean.getNSplitter()]; ]J>{ZL   
nEndPos = new long[bean.getNSplitter()]; bO\E)%zp  
} \rY<DxtOq  
K"U[OZC`  
@Zov&01  
-iJ @K  
} ,CA3Q.y>|  
]\Q9j7}37+  
t~@~XI5  
public void run() w*7BiZ{s<  
{ x;p7n 2_  
//获得文件长度 -P7JaH/Q  
//分割文件 25CO_  
//实例FileSplitterFetch hj|P*yKV  
//启动FileSplitterFetch线程 sJ q^>"|J  
//等待子线程返回 RbGq$vYol/  
try{ JVk"M=c  
if(bFirst) -cW 'g  
{ =`%"-A  
nFileLength = getFileSize(); [W{WfJ-HwG  
if(nFileLength == -1) q]>m#yk   
{ S@PAtB5  
System.err.println("File Length is not known!"); "J(W)\  
} UOAL7  
else if(nFileLength == -2) 6e.?L  
{ BmGY#D,  
System.err.println("File is not access!"); +9d]([Lx  
} Y] "_}  
else ZAcH`r*  
{ @ATJ|5.gr  
for(int i=0;i<nStartPos.length;i++) )`B n"=  
{ uy^vQ/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); FSn&N2[D  
} 8#&axg?a  
for(int i=0;i<nEndPos.length-1;i++) #\X="' /  
{ Yl!~w:O!o  
nEndPos = nStartPos[i+1]; + IpC  
} xesZ 7{ o  
nEndPos[nEndPos.length-1] = nFileLength; \vQjTM-7  
} v;m}<3@'  
} tjIT4  
Yf=Puy}q  
X[Q:c4'  
//启动子线程 .*z Wm  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]-b`uYb  
for(int i=0;i<nStartPos.length;i++) Q7vTTn\  
{ cXY;Tw45  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mqFo`Ee  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c Oi:bC@  
nStartPos,nEndPos,i); UZ` <D/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v Ol<  
fileSplitterFetch.start(); 1ehl=WN  
} i^zncDMA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), sa26u`?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4Y#F"+m.]  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", E,nxv+AQ  
nEndPos = " + nFileLength); 50l! f7  
// fileSplitterFetch[nPos.length-1].start(); ,-GkP>8f(  
B"rfR_B2M#  
f8c'`$O  
//等待子线程结束 _R 6+bB$  
//int count = 0; 6bXR?0$*M.  
//是否结束while循环 ToVi;  
boolean breakWhile = false; WzwH;!  
2a 3RRP  
RZg8y+jM  
while(!bStop) 5!pof\/a  
{ $V0G[!4  
write_nPos(); Bl"BmUn  
Utility.sleep(500); =K ctAR;  
breakWhile = true; ra4$/@3n  
7\?0d!  
iE;D_m.>`O  
for(int i=0;i<nStartPos.length;i++) !8 V  
{ yK3b^  
if(!fileSplitterFetch.bDownOver)  ~;#OQ[  
{ RMfKM! vE  
breakWhile = false; :4V8Iz 71  
break; ".Q``d&X  
} bI_T\Eft  
} O ^+H:Y|  
if(breakWhile) yD-L:)@"  
break; C=&rPUX{  
k,mgiGrQ  
c\\'x\J7  
//count++; BS_ 3|  
//if(count>4) f0lpwwe  
// siteStop(); | pA  
} g$N/pg2>cT  
K_" denzT+  
TOe=6 Z5h  
System.err.println("文件下载结束!"); /#C}1emK  
} dpPu&m+  
catch(Exception e){e.printStackTrace ();} ZHWxU  
} 5@kNvi  
oXxY$x*R1  
\[57Dmo  
//获得文件长度 ls9 28  
public long getFileSize() |v6kZ0B<  
{ 3m#/1=@o  
int nFileLength = -1; aA|<W g  
try{ XJ3p<  
URL url = new URL(siteInfoBean.getSSiteURL()); Ww[Xqmg  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); $k,wA8OZ-  
httpConnection.setRequestProperty("User-Agent","NetFox"); A./ VO  
`v|w&ty*  
b-+~D9U <  
int responseCode=httpConnection.getResponseCode(); 0S%xm'|N  
if(responseCode>=400) l 7XeZ} S  
{ nN]GO}  
processErrorCode(responseCode); 1j!LK-  
return -2; //-2 represent access is error [K=M; $iQ  
} l[AQyR1+/  
:Q=tGj\ G  
lzE{e6  
String sHeader; T|%pvTIe  
b5u8j  
WE*L=_zDS  
for(int i=1;;i++) /qd5{%:  
{ h| T_ k  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); %tOGs80_{  
//Utility.log(in.readLine()); >OLKaghV.5  
sHeader=httpConnection.getHeaderFieldKey(i); ,DZoE~  
if(sHeader!=null) 0eP ]  
{ (T9Q6 \sa  
if(sHeader.equals("Content-Length")) g"dq;H  
{ ]+ KN9  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); L*QX21@wC  
break; EDA%qNd]j  
} S#{jyU9 ]  
} <0w"$.K#3  
else cR *5iqA  
break; 2:6W_[7l!  
} :< d.  
} I0qS x{K  
catch(IOException e){e.printStackTrace ();} 0'QX*xfa>  
catch(Exception e){e.printStackTrace ();} J2BCaAwEP,  
XsXO S8  
<?>1eU%  
Utility.log(nFileLength); (\8~W*ej"  
RXD*;B$v  
~\oF}7l$  
return nFileLength; p|gzU$FWbk  
} x* 9 Xu"?  
J\@W+/#dF  
!2o1c  
//保存下载信息(文件指针位置) MP3Vo|}3  
private void write_nPos() i!a. 6Gq  
{ Sf>#Zqj/  
try{ $0mR_pA\fW  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .DX-biX,  
output.writeInt(nStartPos.length); `B A'a" $  
for(int i=0;i<nStartPos.length;i++) F{*h~7D-|  
{ s;ivoGe}  
// output.writeLong(nPos); 6L!/#d0  
output.writeLong(fileSplitterFetch.nStartPos); \2c 3Nsra  
output.writeLong(fileSplitterFetch.nEndPos); x_+-TC4IXn  
} k',#T932x1  
output.close(); %4QpDt  
} Hh1]\4D,4  
catch(IOException e){e.printStackTrace ();} F<+!28&h  
catch(Exception e){e.printStackTrace ();} /=(PMoZu  
} TlEd#XQgf&  
j%`% DQ  
s0To^I  
//读取保存的下载信息(文件指针位置) _t/~C*=:=  
private void read_nPos() 2bnYYQ14:  
{ z%E ok  
try{ (B^rW,V[R  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); M/mm2?4  
int nCount = input.readInt(); 7@1GSO:Yf  
nStartPos = new long[nCount]; !\}X?G f  
nEndPos = new long[nCount]; B" 0a5-pkr  
for(int i=0;i<nStartPos.length;i++) L[cP2X]NQ  
{ N;q)r  
nStartPos = input.readLong(); cFZcBiw  
nEndPos = input.readLong(); *8I"7'xh  
} 'nT#c[x[0  
input.close(); QG=K^g  
} II'"Nkxd  
catch(IOException e){e.printStackTrace ();} 9R m\@E [  
catch(Exception e){e.printStackTrace ();} I !J'  
} jf^BEz5  
EvKzpxCh  
rQD^O4j R  
private void processErrorCode(int nErrorCode) ]<*-pRN  
{ ,x=S)t  
System.err.println("Error Code : " + nErrorCode); <5 }  
} vk4Q2P  
r,HIoeAKP  
q"e]\Tb=we  
//停止文件下载 $3 =S\jyfK  
public void siteStop() nCS" l5  
{ `*ALb|4ilG  
bStop = true; c[>xM3=e^q  
for(int i=0;i<nStartPos.length;i++) N XCvS0/h  
fileSplitterFetch.splitterStop(); %6W%-`  
{[)n<.n[g  
vB%os Qm  
} gkmV; 0  
} .]e_je_  
//负责部分文件的抓取 )`BKEa f  
**FileSplitterFetch.java p/U{*i ]t  
*/ 4:9N]1JCb  
package NetFox; mIZ6[ ?  
1{A K=H')  
jx{wOb~oO)  
import java.io.*; |[)n.N65 =  
import java.net.*; Y:R*AOx  
EeR}34  
=<%[P9y  
public class FileSplitterFetch extends Thread { ubv>* iO  
Y$5uoq%p3A  
|->C I  
String sURL; //File URL  tE#;$Ss  
long nStartPos; //File Snippet Start Position \^1S:z  
long nEndPos; //File Snippet End Position ox*>HkV  
int nThreadID; //Thread's ID Ae[fW97  
boolean bDownOver = false; //Downing is over SLW|)Q24  
boolean bStop = false; //Stop identical {2)).g  
FileAccessI fileAccessI = null; //File Access interface FP'-=zgc  
Xp.$FJ1)  
w{*PZb4  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException `&9iC 4P  
{ E&N~ h|CL  
this.sURL = sURL; 3$_JNF`  
this.nStartPos = nStart; dmWCNeja.  
this.nEndPos = nEnd; aJ QzM  
nThreadID = id; fC".K Yjp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 !nsx!M  
} LS$zA>:  
+s;>@j()V  
O 6ph_$nt.  
public void run() [MuZ^'dR  
{ M1icj~Jr  
while(nStartPos < nEndPos && !bStop) !zfKj0^  
{ /i~x.i3  
!QpOrg  
}xry  
try{ x"n++j  
URL url = new URL(sURL); & 'CUc/,  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); npd:aGx  
httpConnection.setRequestProperty("User-Agent","NetFox"); 15S&,$ 1&  
String sProperty = "bytes="+nStartPos+"-"; }K5okxio  
httpConnection.setRequestProperty("RANGE",sProperty); I^nDO\m <  
Utility.log(sProperty); \(RD5@=!4#  
S1[, al  
"x vizvR  
InputStream input = httpConnection.getInputStream(); U:z5`z!  
//logResponseHead(httpConnection); ]q~bi<E9W  
@qpj0i+>*  
(:I]v_qEYS  
byte[] b = new byte[1024]; Qvty;2$o@  
int nRead;  T  5F)  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %fnG v\uI  
{ Y1ks'=c>  
nStartPos += fileAccessI.write(b,0,nRead); W*Si"s2  
//if(nThreadID == 1) jfiUf1Mj  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 9Z21|5  
} JA*+F1s  
0'HQ=pP  
ps;dbY*s6  
Utility.log("Thread " + nThreadID + " is over!"); %E5b }E#  
bDownOver = true; 16>D?;2o(  
//nPos = fileAccessI.write (b,0,nRead); ,kf.'N  
} ^|SiqE  
catch(Exception e){e.printStackTrace ();} 2]<.m]  
} yVp,)T9  
} @dUN3,}  
?5jLN&A3 G  
Se_]=>WI  
//打印回应的头信息 '$c9S[  
public void logResponseHead(HttpURLConnection con) `yP`5a/  
{ g60k R7;\  
for(int i=1;;i++) l2kGFgc  
{ DJ DQH\&  
String header=con.getHeaderFieldKey(i); #N"u 0  
if(header!=null) lWe cxD$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); tS>^x  
Utility.log(header+" : "+con.getHeaderField(header)); LP=y$B  
else R*!s'R  
break; JEk'2Htx  
} <:Mz2Rg  
} aU~?&]  
E%DT;1  
qY$ [2]  
public void splitterStop() ] j8bv3  
{ d!UxFY@  
bStop = true; co~NXpqg  
} yQ$]`hr;  
7FJ4;HLQ  
c -PZG|<C[  
} TZ+ p6M8G  
araXE~Ac  
7f}uRXBV$A  
/* 8]Tv1Wc  
**FileAccess.java ,~=]3qmbR  
*//文件访问(定位,写) - om9 Z0e  
package NetFox; .>eRX%  
import java.io.*; NhCucSU<K  
P1Z"}Qw  
p20JU zy  
public class FileAccessI implements Serializable{ v7SYWO#  
n| {#5#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 SDC'S]{ew  
RandomAccessFile oSavedFile; M2-`p  
long nPos; SAdE9L =d  
e b} P/  
*!ng)3#  
public FileAccessI() throws IOException Ps>:|j+  
{ 9OV@z6  
this("",0); YR*gO TD  
} (jA5`4>u  
L2,2Sn*4i  
Z3weFbCH  
public FileAccessI(String sName,long nPos) throws IOException !8[T*'LJ-  
{ 4`,7 tj  
oSavedFile = new RandomAccessFile(sName,"rw"); DtFHh/X  
this.nPos = nPos; L7Hv)  
oSavedFile.seek(nPos); v@soS1V!  
} o0]YDX@T  
nj'5iiV`]  
KCW2 UyE]  
public synchronized int write(byte[] b,int nStart,int nLen) Q(]m1\a  
{ w8w0:@0(  
int n = -1; l)vC=V6MG  
try{ mpug#i6q  
oSavedFile.write(b,nStart,nLen); Bd <0}  
n = nLen; t\hnnu`Pq  
} W06#|8,{v  
catch(IOException e) Zs />_w}  
{ &F uPd}F  
e.printStackTrace (); a1~|?PCbY  
} J<;io!  
&J&'J~N  
hNM8H  
return n; 6qHD&bv\%C  
} Tj#S')s8  
< j:\;mi;  
12z!{k7N  
} oj - `G  
le\-h'D  
*,4rYb7I w  
/* $G`CXhbl  
**SiteInfoBean.java \ saV8U7B  
*/ pOXI*0_g.  
package NetFox; ?"mZb#%  
lc[6Mpi7s[  
nsR CDUCi  
public class SiteInfoBean { xqzeBLU  
.DhI3'Jrl  
@01.Pd   
private String sSiteURL; //Site's URL iHGVR  
private String sFilePath; //Saved File's Path UeO/<ml3>J  
private String sFileName; //Saved File's Name VKDOM0{V  
private int nSplitter; //Count of Splited Downloading File P}}G9^  
d\JaYizp  
\{ @m  
public SiteInfoBean() Eo6N'h>h  
{//nSplitter的缺省值为5 =G:Krc8w@  
//default value of nSplitter is 5 fA6IW(_bi  
this("","","",5); rJpr;QKf%  
} 6}TunR  
*~)6 sm  
E:x@O8F  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g:M;S"U3*Y  
{ K<e #y!  
sSiteURL= sURL; yMz#e0k  
sFilePath = sPath; m"n74 cxS  
sFileName = sName; fWmc$r5n](  
this.nSplitter = nSpiltter; ,2fi`9=\  
]ZcivnN#  
x vs=T  
} .jCGtR )%  
* @4@eQF  
9fEe={ B+  
public String getSSiteURL() 'Gn>~m  
{ T]De{nHu  
return sSiteURL; SA +d4P_T  
} +c))fPuV  
)XDBK* !  
YRlfU5  
public void setSSiteURL(String value) KEOk%'c,  
{ +>#SNZ[  
sSiteURL = value; [[ ie  
} GQtNk<?$I  
i!%bz  
8gP1]xD  
public String getSFilePath() (SyD)G\rj  
{ i<"lXu  
return sFilePath; ?}KRAtJ8  
} D5lQ0_IeW  
NfvPE]S  
!q2zuxq!R  
public void setSFilePath(String value) D.a>i?W  
{ 61S;M8tNv  
sFilePath = value; Y"mFUW4  
} Keh=>K)T  
9-;-jnDy  
4aS}b3=n  
public String getSFileName() dEJqgp}\p  
{ A9.TRKb=8  
return sFileName; ^O_Z5NbC3  
} spV7\Gs.@  
|8k1Bap`z  
sF {,n0<8  
public void setSFileName(String value) `9^tuR,  
{ |{N{VK  
sFileName = value; +K1M&(  
} G,)zn9X  
j}^w :W76  
2<@2_wSJ  
public int getNSplitter() Y :!L  
{ ?@rd,:'dE  
return nSplitter; {XOl &  
} '0HOL)cIz  
cU6*y!}9  
Ek L2nI  
public void setNSplitter(int nCount) Mh)? A/e  
{ D~C'1C&W  
nSplitter = nCount; Y*NzY*V\  
} VE+H! ob A  
} uV5uZ  
<8:h%%$?  
<F7a!$zQ  
/* ' h7Faj  
**Utility.java QF>T)1&J[7  
*/ &*v\t\]  
package NetFox; UMGiJO\yH  
7zG r+Px  
$r!CQ 2S  
public class Utility { ~7 i{~<?  
T`x|=}  
{srP3ll P  
public Utility() `;UWq{"  
{  pQiC#4b  
]DNPG"  
]}v]j`9m%  
} b}K,wAx  
p [Po*c.b  
//线程睡眠 hP"2X"kz&  
public static void sleep(int nSecond) {:1j>4m 2  
{ i\sBey ND"  
try{ >bW=oTFz  
Thread.sleep(nSecond); E.K^v/dNdq  
} joe)b  
catch(Exception e) d/; tq  
{ cw<I L  
e.printStackTrace (); *z~,|DQ(A  
} Cab.a)o  
} t7]j6>MK3q  
F rc  kA  
//日志 & P-8_I  
public static void log(String sMsg) *JJ8\R&P0  
{ jYp!?%!  
System.err.println(sMsg); Jq/itsg  
} {+67<&g  
~IhM(Q*mO!  
m]n2wmE3n  
public static void log(int sMsg) "V p nr +6  
{ QEr<(wM-y  
System.err.println(sMsg); :H]d1  
} 4#IT" i  
} 2VN].t:  
#gC [L=01  
?EFRf~7JP  
/* G[k3`  
**TestMethod.java e0`z~z]6&  
*/ hY&Yp^"}]^  
package NetFox; k6b ct@7  
Q!+AiSTU  
OFtaOjsyUa  
public class TestMethod { jqaX|)8|$  
m'"r<]pB*4  
Skt-5S#  
public TestMethod() wMVUTm  
{ ///xx/weblogic60b2_win.exe 91]|4k93  
try{ WoTeIkM9  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); gv`_+E{P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5 bI :xL}  
SiteFileFetch fileFetch = new SiteFileFetch(bean); K%J?'-  
fileFetch.start(); `58%&3lp  
} Yz/Blh%V  
catch(Exception e){e.printStackTrace ();} ^\ [p6>  
leC!Yj  
[.}qi[=n  
} 1$0Kvvg[  
vfkF@^D  
2d .$V,U<  
public static void main(String[] args) *Ypn@YpSp  
{  t;o\"H  
new TestMethod(); F'K >@y  
} cr!8Tp;2A  
} P*&[9 )d6  
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