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http断点续传简单实现(java)

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/* 0g#?'sD  
**SiteFileFetch.java iEFS>kL8e  
*/ /-pop]L  
package NetFox; RmN\;G?}  
import java.io.*; ;c~DBJg'|  
import java.net.*; F7x< V=4{  
@7PE&3  
`0ju=FP'u5  
public class SiteFileFetch extends Thread { A&'HlI% J  
F0NNS!WP7^  
(aCl*vV1  
SiteInfoBean siteInfoBean = null; //文件信息Bean J! eVw\6  
long[] nStartPos; //开始位置 hG'2(Y!  
long[] nEndPos; //结束位置 Z.LF5ur  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 S67T:ARS  
long nFileLength; //文件长度 a-TsD}'X  
boolean bFirst = true; //是否第一次取文件 zGFW?|o<  
boolean bStop = false; //停止标志 [TV"mA  
File tmpFile; //文件下载的临时信息 8<^6<c  
DataOutputStream output; //输出到文件的输出流 ^_ZQf  
:kI x?cc  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) X'bp?m  
public SiteFileFetch(SiteInfoBean bean) throws IOException }Lwj~{  
{ .yj=*N.  
siteInfoBean = bean; 48%a${Nvvj  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); c9E9Rx  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); T{K+1SPy4  
if(tmpFile.exists ()) o:Z*F0qm  
{ +FVcrL@  
bFirst = false; >-y&k^a=  
read_nPos(); <Q-ufF85)  
} S+OI?QS  
else ")M.p_b[Z=  
{ 8CSvg{B  
nStartPos = new long[bean.getNSplitter()]; !c`Q?aGV)  
nEndPos = new long[bean.getNSplitter()]; 0\}j[-`pF  
} Y=rW.yK8  
Js#c9l{{  
zZh`go02E  
M!6bf  
} z8"=W,2  
|V~P6o(/  
R QO{fC  
public void run() NtOR/*  
{ Mw5!9@Fc7  
//获得文件长度 "AVj]jR  
//分割文件 k~?}z.g(  
//实例FileSplitterFetch v <Ze$^ e&  
//启动FileSplitterFetch线程 )J88gMk+  
//等待子线程返回 RBgkC+2  
try{ izW l5}+'B  
if(bFirst) 3S2'JOTY  
{ i+cGw  
nFileLength = getFileSize(); +[ }]a3)  
if(nFileLength == -1) G7/LYTT)  
{ Z/RUrYeb  
System.err.println("File Length is not known!"); <,hBoHZSL  
} ze\~-0ks +  
else if(nFileLength == -2) IKr7"`  
{ |95/'a*  
System.err.println("File is not access!"); `oz7Q(`  
} 246lFx G.  
else /+1Fa):  
{ `Zi#rr|)L  
for(int i=0;i<nStartPos.length;i++) o5$K^2^g  
{ K+$c,1wb  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {4m"S 7O  
} a&ByV!%%+_  
for(int i=0;i<nEndPos.length-1;i++) ft6^s(t  
{ A0X0t  
nEndPos = nStartPos[i+1]; O.}gG6u5  
} tB3CX\e  
nEndPos[nEndPos.length-1] = nFileLength; yaR;  
} V= *J9~K  
} -5 W0K}  
<d5vVn  
I !<v$  
//启动子线程 A7RX2  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; #f~a\}$I  
for(int i=0;i<nStartPos.length;i++) d,+n,;6Cf  
{ jb![ Lp  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dS&8R1\>1  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), g^4FzJ  
nStartPos,nEndPos,i); =U2Te  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C;) xjZiR  
fileSplitterFetch.start(); _~(Xd@c(  
} @ :4Kk 4g1  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), pNJM]-D]m~  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); .- Lqo=o\  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", n1/lE)  
nEndPos = " + nFileLength); Wkk Nyg,  
// fileSplitterFetch[nPos.length-1].start(); 1;gSf.naG  
2!otVz! Mh  
,< icW &a  
//等待子线程结束 uWInx6p  
//int count = 0; QPcB_wUqu  
//是否结束while循环 >oNk(. %  
boolean breakWhile = false; Z%{f[|h9}  
GDB>!ukg  
U44H/5/  
while(!bStop) +=k|(8Js#  
{ l.W:6", w  
write_nPos(); oX4uRc7wR  
Utility.sleep(500); GKtQ>39B  
breakWhile = true; 5#o,]tP  
(*x "6)`  
k0IU~y%  
for(int i=0;i<nStartPos.length;i++) ] zY  
{ WO9/rF_  
if(!fileSplitterFetch.bDownOver) bC{8yV=)  
{  :Y3?,  
breakWhile = false; m'B6qy!}6  
break; K)@}Ok"#\4  
} WLl9>v^1  
} j1kc&(  
if(breakWhile) `x VA]GR4c  
break; zNf5OItx  
UIj/Id  
dZgfls  
//count++; ):@%xoF5  
//if(count>4) :GYv9OG  
// siteStop(); R4(8]oUW  
} /6c10}f  
P[K=']c  
m^.C(}  
System.err.println("文件下载结束!"); %4Zy1{yKs_  
} jf/9]`Hf  
catch(Exception e){e.printStackTrace ();} 6I#DlAU@v  
} $IT9@}*{  
?63JQ.;  
fLoVcl  
//获得文件长度 ] O>7x  
public long getFileSize() \pGO}{3 e*  
{ Z5[:Zf?h7J  
int nFileLength = -1; LeyDs>! 0  
try{ 8Q -F  
URL url = new URL(siteInfoBean.getSSiteURL()); \Agg6tY r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); \W^+vuD8  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8!6*|!,:?n  
hob$eWgr  
*^Y0}?]qT  
int responseCode=httpConnection.getResponseCode(); 3raA^d3!?  
if(responseCode>=400) iGMONJRO  
{ ZG<!^tj  
processErrorCode(responseCode); pd3&AsU  
return -2; //-2 represent access is error ,P@-DDJ  
} *$C[![   
yWtr,  
u(Sz$eV  
String sHeader; a?~csP^?}  
!@Lc/'w  
CHit  
for(int i=1;;i++) %:?QE ;  
{ xN8JrZE&  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); SqF.DB~  
//Utility.log(in.readLine()); !gHWYWu)!  
sHeader=httpConnection.getHeaderFieldKey(i); :[f`HY&  
if(sHeader!=null) QS*cd|7J;  
{ X", 0VO  
if(sHeader.equals("Content-Length")) qjzW9yV+  
{ wP0+Xv,  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); c@7hLUaE2  
break; TF-Ty  
} So.P @CCd  
} jY+S,lD  
else ,GU/l)os`  
break; ,D2_Z]  
} gCr|e}w-  
} PZRn6Tc  
catch(IOException e){e.printStackTrace ();} .{ a2z*o  
catch(Exception e){e.printStackTrace ();} *;E+9^:V  
{b0&qV   
8Vhck-wF  
Utility.log(nFileLength); X6GkJ R  
+JS/Z5dl+}  
6n\z53Mk  
return nFileLength; kseJm+Hc  
} _I-VWDCk  
 &Z!K]OSY  
H&Y{jqua  
//保存下载信息(文件指针位置) CN~NyJL H  
private void write_nPos() PFy;qk  
{ e)dWa'2<  
try{ D8AIV K]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !LOors za  
output.writeInt(nStartPos.length); )z235}P  
for(int i=0;i<nStartPos.length;i++) {a8^6dm*E  
{ DE\bYxJ  
// output.writeLong(nPos); uE#,c\[8  
output.writeLong(fileSplitterFetch.nStartPos); g+ 1=5g  
output.writeLong(fileSplitterFetch.nEndPos); /:{_|P\  
} D>b5Uwt  
output.close(); <-B"|u  
} 'Rd*X6dv  
catch(IOException e){e.printStackTrace ();} @@3,+7%1  
catch(Exception e){e.printStackTrace ();} w1@b5-  
} a<wQzgxG  
FEZ"\|I|  
5YI/Ec  
//读取保存的下载信息(文件指针位置) F0'A/T'ht  
private void read_nPos() fb.\V]K  
{ F:o #  
try{ I,4-  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ,o@~OTja*  
int nCount = input.readInt(); =ch Af=  
nStartPos = new long[nCount]; WCmNibj  
nEndPos = new long[nCount]; m_!vIUOz  
for(int i=0;i<nStartPos.length;i++) 4!~ .6cp3  
{ Qj<{oZp&  
nStartPos = input.readLong(); QK!:q{  
nEndPos = input.readLong(); lAn+gDP  
} "R2t&X[9  
input.close(); DxKfWb5 R  
} .d~]e2x  
catch(IOException e){e.printStackTrace ();} V l~Y  
catch(Exception e){e.printStackTrace ();} xPDA475Cw3  
} F\=Rm  
Vx6? @R  
fH e0W  
private void processErrorCode(int nErrorCode) yOUX E>-  
{ (ND5CKCR^  
System.err.println("Error Code : " + nErrorCode); S`@6c$y k  
} *M&VqG4P9w  
3_\{[_W  
,> (bt%b  
//停止文件下载 }x?H ~QQT  
public void siteStop() 1KYbL8c  
{ 8S1P&+iKs  
bStop = true; RHx+HBZ  
for(int i=0;i<nStartPos.length;i++) )0U3w#,JQ  
fileSplitterFetch.splitterStop(); !<=%;+  
EN-H4F  
..q63dr  
} v=*Bb3dt  
} juCG?}di;  
//负责部分文件的抓取 XnE %$NJ  
**FileSplitterFetch.java 9jMC |oE  
*/  H\=LE  
package NetFox; g>!:U6K  
2&gd"Ak(  
jKj=#O  
import java.io.*; sArje(5Eo  
import java.net.*; t8A kdSU0  
p<HTJ0  
NDRW  
public class FileSplitterFetch extends Thread { XatA8(_,5  
s ~Lfi.  
:J Gl>V  
String sURL; //File URL 'n^2|"$sH  
long nStartPos; //File Snippet Start Position 0\cnc^Z  
long nEndPos; //File Snippet End Position 1c)\  
int nThreadID; //Thread's ID %Ui{=920  
boolean bDownOver = false; //Downing is over %wt2F-u  
boolean bStop = false; //Stop identical i5 L:L  
FileAccessI fileAccessI = null; //File Access interface ` /I bWu  
!f\?c7  
Gpdv]SON{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException dNUR)X#e  
{ vXy uEEe  
this.sURL = sURL; *|LbbRu  
this.nStartPos = nStart; E[jXUOu-  
this.nEndPos = nEnd; Q(IJD4  
nThreadID = id; R%b*EBZ  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /`+Hw dk  
} k<YtoV  
8ji^d1G,  
v}F4R $  
public void run() aJ :A%+1  
{ Xr?>uqY!M  
while(nStartPos < nEndPos && !bStop) ='dLsh4P2N  
{ 1 [Sv  
YVB% kKv{  
(px*R~}  
try{ ]{IR&{EI-  
URL url = new URL(sURL); lx{.H,1~  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); &GdL 9!hH  
httpConnection.setRequestProperty("User-Agent","NetFox"); r]k*7PK  
String sProperty = "bytes="+nStartPos+"-"; Kajkw>z  
httpConnection.setRequestProperty("RANGE",sProperty); y)3~]h\a  
Utility.log(sProperty); &l. x:eD  
5-8]N>/b!  
`*e4m  
InputStream input = httpConnection.getInputStream();  6R;)  
//logResponseHead(httpConnection); C9<4~IM w  
45x,|h[F{5  
xClRO,-  
byte[] b = new byte[1024];  r=fE8[,  
int nRead; !uWxRpT,7  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) cVQatm  
{ &sm @  
nStartPos += fileAccessI.write(b,0,nRead); owE<7TGPI?  
//if(nThreadID == 1) 29"mE;j  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EHpu*P~W  
} YXF#c)#  
= :Po%Z%{  
XnBm`vk?V!  
Utility.log("Thread " + nThreadID + " is over!"); bnijM/73  
bDownOver = true; sS, zzx<  
//nPos = fileAccessI.write (b,0,nRead); C _8j:Z&  
} .aNO( /kO  
catch(Exception e){e.printStackTrace ();} 7w "sJ  
} `FUFK/7 w\  
} p QluGIX0V  
[J~aAB  
z*6$&sS\>  
//打印回应的头信息 ZV!R#Xv  
public void logResponseHead(HttpURLConnection con) EVR! @6@  
{ r2RBrZ@1  
for(int i=1;;i++) &&;ex9  
{ P?^JPbfV  
String header=con.getHeaderFieldKey(i); 3PfiQ|/b  
if(header!=null) eh$G.-2N  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Q>kiVvc  
Utility.log(header+" : "+con.getHeaderField(header)); saatU;V  
else K<c2PFo)Q  
break; y:Z$LmPc<  
} z{%oJ_  
} y k?SD1hj  
j7f5|^/x3  
Ll,I-BQ 9  
public void splitterStop() mHKJ  
{ t-_#Q bzE{  
bStop = true; f, |QAj=a  
} 1{^CfamF  
V {p*z  
x@h tx?   
} eaEbH2J  
W+KF2(lB  
+|6`E3j%  
/* O{~KR/  
**FileAccess.java Gc wt7~  
*//文件访问(定位,写) FtE90=$  
package NetFox; ^Sw2xT$p{j  
import java.io.*; \H^;'agA  
veV_be{i  
j(sLK &  
public class FileAccessI implements Serializable{ i&JpM] N  
+vf:z?I8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 J2m"1gq,  
RandomAccessFile oSavedFile; <P- $RX  
long nPos; Q |%-9^  
C ck#Y  
Y.7}  
public FileAccessI() throws IOException MZ WmlJ   
{ w^3|(F  
this("",0); E$ {J  
} 6.[)`iF+#  
?H`j>]%&  
6F(hY !}5  
public FileAccessI(String sName,long nPos) throws IOException wZQ)jo7*g  
{ guU=NQZ  
oSavedFile = new RandomAccessFile(sName,"rw"); $(3uOsy   
this.nPos = nPos; >Co)2d]  
oSavedFile.seek(nPos); " CM ucK  
} opXDm\  
"e@n:N!  
7{4w 2)  
public synchronized int write(byte[] b,int nStart,int nLen) YGETMIT(  
{ Y3k[~A7X  
int n = -1; e gI&epN  
try{ 19p8B&  
oSavedFile.write(b,nStart,nLen); uxb:^d?D!  
n = nLen; :5jexz."M  
} #BsW  
catch(IOException e) P].eAAXnP  
{ `kFiH*5%z  
e.printStackTrace (); r_^)1w  
} "Kq>#I'%W  
FI$XSG  
g rspt}  
return n; t{zBC?c R  
} `;$h'eI9  
->h5T%sn  
h,t:]  
} P3!Atnv2  
z6I%wh  
d*2u}1Jo8  
/* NO2(vE  
**SiteInfoBean.java Vc _:*  
*/ W qE '(  
package NetFox; !>3LGu,  
;}K62LSR  
6J\fF tB@V  
public class SiteInfoBean { >La><.z~  
q(Hip<6p  
O[FZq47  
private String sSiteURL; //Site's URL >I^9:Q  
private String sFilePath; //Saved File's Path p?JQ[K7i  
private String sFileName; //Saved File's Name Z/g]o#  
private int nSplitter; //Count of Splited Downloading File >?I/;R.-  
5$%XvM  
doR4nRl9  
public SiteInfoBean() 0q#"clw  
{//nSplitter的缺省值为5 n1,S_Hs  
//default value of nSplitter is 5 JRY_ nX  
this("","","",5); Zj!Abji=O  
} FshC )[w,  
2 x32U MD  
e>AXXUEf  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) |@wyC0k!  
{ f@d9Hqr+l;  
sSiteURL= sURL; yQ%"U^.m  
sFilePath = sPath; nxfoWy  
sFileName = sName; ~8{sA5y  
this.nSplitter = nSpiltter; Om9jtWk  
_{)9b24(  
s$ z2 c  
} \f%.n]>  
8EI:(NE*J  
"%@v++4y  
public String getSSiteURL() X{\jK]O  
{ S)7/0N79A  
return sSiteURL; J+ts  
} Oaa"T8t  
2w?hgNz  
vy9dAl  
public void setSSiteURL(String value) ]iVLHVqz  
{ Ur3m[07H  
sSiteURL = value; WbcS: !0  
} 4TZ cc|B5  
J# EP%  
5FOqv=6S  
public String getSFilePath() jDX>izg;V  
{ -[heV|$;  
return sFilePath; Wekqn!h  
}  #^0(  
i=#F)AD^5#  
!OAvD#  
public void setSFilePath(String value) %u!b& 5]e  
{ !MV@) (.  
sFilePath = value; v* ~3Z1  
} suVmg-d  
FFvCi@oT  
*x(Jq?5O7X  
public String getSFileName() r4Q|5kT*i  
{ zK;XF N#U^  
return sFileName; e;(  
} VaR/o#  
E!mmLVa9  
b1-&v|L  
public void setSFileName(String value) v&;:^jJ8  
{ D*2\{W/  
sFileName = value; Gu;OV LR|  
} bRsTBp;R`I  
tj5giQ3DG)  
z7T0u.4Ss  
public int getNSplitter() tC)6  
{ 6N" l{!  
return nSplitter; ~x]9SXD%  
} Dl,`\b@Fw3  
2*1ft>Uty  
RN9;kB)c  
public void setNSplitter(int nCount) RUo9eQIPD  
{ -LWK*q[J;*  
nSplitter = nCount; +B"0{>n}F  
} Gquuy7[&  
} $NG++N  
Mvcfk$pA  
ar ^i|`D  
/* $k%Z$NSN=  
**Utility.java :YO@_  
*/ sWqM?2g  
package NetFox; cUk*C  
>*1}1~uU`'  
qTmD '2  
public class Utility { ,hRN\Kt)p  
$>q@SJ1q  
1cC1*c0Z  
public Utility() z&}-8JykH  
{ go'j/4Tp  
/'wF2UR  
^jSsa  
} T@ YGB]*Y  
h{'t5&yY  
//线程睡眠 }NCL>l;q  
public static void sleep(int nSecond) /aqEJGG>  
{ +%0z`E\?M#  
try{ bS!\#f%9"  
Thread.sleep(nSecond); vjUp *R>h  
} bGmx7qt#  
catch(Exception e) 8e2?tmWM  
{ *hY2.t; X  
e.printStackTrace (); X#p Wyo~  
} K8[DZ)rO;Z  
} 1hmc,c  
%X1x4t]  
//日志 z`3( ,V  
public static void log(String sMsg) l67Jl"v  
{ diT=x52  
System.err.println(sMsg); cgT  
} (< c7<_-H  
= |U@  
TzG]WsY_  
public static void log(int sMsg) o l ({AYB  
{ sen=0SB/  
System.err.println(sMsg); zI;0&  
} WF2-$`x  
} ~r*P]*51x  
dcfe_EuT  
EqB)sK/3  
/* Ip *g'  
**TestMethod.java ~mp0B9L%  
*/ H=^K@Ti:  
package NetFox; <V&5P3)d9  
 IDFFc&  
p Pro }@@  
public class TestMethod { 5/0j}_pP  
1DJekiWf  
NL"G2[e  
public TestMethod() )A8v];.]3  
{ ///xx/weblogic60b2_win.exe `BXS)xj  
try{ c-4STPNQi  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); $'wq1u  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);  %Y nmuZ  
SiteFileFetch fileFetch = new SiteFileFetch(bean); dA~ 3>f*b_  
fileFetch.start(); 5K%W a]W  
} ~Ci{3j :]  
catch(Exception e){e.printStackTrace ();} iz[gHB  
MgMD\  
lS5ny  
} ^TdZ*($5  
~N0 sJ%  
V!/:53  
public static void main(String[] args) z8_XX$Mnt  
{ KOSM]c\H  
new TestMethod(); YK#fa2ng  
} 0y#Ih {L  
} |V,<+BEi  
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