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http断点续传简单实现(java)

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/* nuH=pIq6x  
**SiteFileFetch.java 2##;[  
*/ *8r^!(Kj  
package NetFox; f$76p!pDa  
import java.io.*; Vy=P*  
import java.net.*; 3n,jrX75u  
cO$xT;kK  
|k$6"dXSO  
public class SiteFileFetch extends Thread { P!Brw72  
)SZzA'  
QLH!>9Ch  
SiteInfoBean siteInfoBean = null; //文件信息Bean i 50E#+E8  
long[] nStartPos; //开始位置 en>n\;U  
long[] nEndPos; //结束位置 u*f`\vs  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /W GD7\G'8  
long nFileLength; //文件长度 |LW5dtQ  
boolean bFirst = true; //是否第一次取文件 [tT_ z<e`  
boolean bStop = false; //停止标志 yh2)Pc[  
File tmpFile; //文件下载的临时信息 S B~opN  
DataOutputStream output; //输出到文件的输出流 -Uan.#~S  
 5@DCo  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Mw3$QRM  
public SiteFileFetch(SiteInfoBean bean) throws IOException E{0e5.{  
{ in K]+H]{  
siteInfoBean = bean; + -uQ] ^n  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); DIABR%0  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); &gJ1*"$9  
if(tmpFile.exists ()) B(WmJ6e  
{ Wv|CJN;4  
bFirst = false; 4E2#krE%  
read_nPos(); NN#k^[i1  
} Gphy8~eS  
else n }b{u@$  
{ XV/7K "  
nStartPos = new long[bean.getNSplitter()]; E[WU  
nEndPos = new long[bean.getNSplitter()]; L3w.<h  
} JH| D  
W[I$([  
i=L 86Ks  
p5jR;nOZ%l  
} !E&l=* lM.  
F?$Vx)HI  
vf zC2  
public void run() j,Mbl"P  
{ [[HCP8Wk   
//获得文件长度 udT0`6l;  
//分割文件 V:#rY5X  
//实例FileSplitterFetch gg.]\#3g  
//启动FileSplitterFetch线程 <THw l/a  
//等待子线程返回 6fo\ z2  
try{ @  R[K8  
if(bFirst) ~n8UN<  
{ j85B{Mab&  
nFileLength = getFileSize(); FShUw+y  
if(nFileLength == -1) A@Q6}ESD  
{ v-N4&9)%9  
System.err.println("File Length is not known!"); O}%E SAB  
} !ui t  
else if(nFileLength == -2) JNY?] |=  
{ tmOy"mq67  
System.err.println("File is not access!"); "n]x%. *  
} l9C `:g  
else gyq6LRb  
{ CuK>1_Dq  
for(int i=0;i<nStartPos.length;i++) T_!F I29  
{ 0r_~LN^|[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Oe x   
} ]h~F%   
for(int i=0;i<nEndPos.length-1;i++) ZBR^$?nj  
{ BdMd\1eMw  
nEndPos = nStartPos[i+1]; H#7=s{u  
}  6/#+#T  
nEndPos[nEndPos.length-1] = nFileLength; '%4fQ%ID}  
} W**[:n+  
} 9+MW13?  
=dH=3iCG  
KB^8Z@(+  
//启动子线程 V,=5}qozQ  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; XlD=<$Nk7  
for(int i=0;i<nStartPos.length;i++) iZ>P>x\  
{ p6NPWaBR  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _h4]gZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), !?_CIt$p  
nStartPos,nEndPos,i); akk*f+TD`  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); FAL#p$y}  
fileSplitterFetch.start();  ZB |s/  
} B8eZ}9X  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ZV:df 6S  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ]zVQL_%,  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", .?rs5[th*  
nEndPos = " + nFileLength); oQrfrA&=M  
// fileSplitterFetch[nPos.length-1].start(); ]]_5_)"4  
8G3 Z,8P4(  
1) K<x  
//等待子线程结束 x${C[gxq9F  
//int count = 0; L-)ZjXzk  
//是否结束while循环 &OZx!G^Z  
boolean breakWhile = false; :-#7j} R&  
T59FRX  
"=n%L +6%  
while(!bStop) nTc#I~\  
{ -~aG_Bp!($  
write_nPos(); cWyf04-?  
Utility.sleep(500); WMnSkO  
breakWhile = true; W!T[ ^+  
s-5 #P,Lw  
r>! @Z2%s  
for(int i=0;i<nStartPos.length;i++) 9(qoME}>=  
{ p>kny?AJ  
if(!fileSplitterFetch.bDownOver) q+4dHS)x  
{ 5x|$q kI  
breakWhile = false; p#Po?  
break; Q=d:Yz":S  
} /s%-c!o^  
} )X," NJG  
if(breakWhile) -W.-m2:1  
break; V~#5^PF{  
I$S*elveG  
Du +_dr^4  
//count++; "=+i~N#Sc  
//if(count>4) WF*j^ %5  
// siteStop(); ?$ov9U_  
} ~:k r;n2  
)7!,_r  
%QrOEs  
System.err.println("文件下载结束!"); <$hv{a  
} 4YI6&  
catch(Exception e){e.printStackTrace ();} c%O97J.5b  
} Ek_&E7  
)MSCyPp5  
k&:q|[N  
//获得文件长度 @aN~97 H\  
public long getFileSize() k"%JyO8Y  
{ %).I &)i  
int nFileLength = -1; AX&Emz-  
try{ #g@4c3um|  
URL url = new URL(siteInfoBean.getSSiteURL()); >TM{2b,(p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [O'aka Q  
httpConnection.setRequestProperty("User-Agent","NetFox"); `KLr!<i()  
fj['M6+wd  
R\X;`ptT  
int responseCode=httpConnection.getResponseCode(); \2[tM/+Bs  
if(responseCode>=400) %-fS:~$  
{ p %.Adxx  
processErrorCode(responseCode); g$mMH  
return -2; //-2 represent access is error bC"h7$3  
} Ac{TqiIv  
^b~ZOg[p  
_t;^\"\  
String sHeader; -IVWkA)7  
OGLA1}k4  
_1O .{O  
for(int i=1;;i++) qhG2j;  
{ mJd8?d  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 4 ;)t\9cy_  
//Utility.log(in.readLine()); %"oGJp  
sHeader=httpConnection.getHeaderFieldKey(i); G;#xcld  
if(sHeader!=null) YahW%mv`d  
{ T`j {2  
if(sHeader.equals("Content-Length")) 55TFBDc  
{ kI04<!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Het>G{  
break; %Jd!x{a`>A  
} Av yer/{  
} ~ArRD-_t  
else a%a0/!U[  
break; >dgq2ok!u  
} ar 7.O;e  
} _qk&W_u  
catch(IOException e){e.printStackTrace ();} \(=xc2  
catch(Exception e){e.printStackTrace ();} v9,cL.0&  
|;(P+Q4lB  
IO7gq+  
Utility.log(nFileLength); A /c  
/E{tNd^S  
-Jv3D$f]a  
return nFileLength; "".a(ZGg  
} :/6aBM?  
v8'XchJ  
.}eM"Kv  
//保存下载信息(文件指针位置) .waj.9&[l  
private void write_nPos() R}3th/qf  
{ K0o${%'@7  
try{ wpC .!T  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ki2 `gLK  
output.writeInt(nStartPos.length); =zrfh-lwH  
for(int i=0;i<nStartPos.length;i++) @c"s6h&  
{ eHGx00:  
// output.writeLong(nPos); :5&UWL|  
output.writeLong(fileSplitterFetch.nStartPos); M&q~e@P  
output.writeLong(fileSplitterFetch.nEndPos); DnhbMxh8o  
} 90Sras>F  
output.close(); k#~oagW_Gw  
} AY"wEyNU  
catch(IOException e){e.printStackTrace ();} sUR5Q/Q  
catch(Exception e){e.printStackTrace ();} FqGMHM\J  
} )MTf  
yP} |8x  
nQ|($V1?W  
//读取保存的下载信息(文件指针位置) Y`$\o  
private void read_nPos() 50A\Y)i_mZ  
{ xe(7q1   
try{ g2^{+,/^K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); iqB%sIP  
int nCount = input.readInt(); 2!CL8hG5:  
nStartPos = new long[nCount]; $_eJ@L#  
nEndPos = new long[nCount]; S= `$w  
for(int i=0;i<nStartPos.length;i++) GcA|JS=>  
{ wL]#]DiE  
nStartPos = input.readLong(); `HYj:4v'  
nEndPos = input.readLong(); 2?:OsA}  
} (d,O Lng  
input.close(); MT)q?NcG  
} ^ r(]S%  
catch(IOException e){e.printStackTrace ();} 8KkN "4'  
catch(Exception e){e.printStackTrace ();} PA*k |  
} ?UIW&*h}  
Z 5P4 H  
l= Jw6F+5  
private void processErrorCode(int nErrorCode) pV\> ?  
{ Z-_Xt^N  
System.err.println("Error Code : " + nErrorCode); 7B5b +  
} PBEi"`i  
-bSM]86  
Pf?&ys6  
//停止文件下载 CK|AXz+EN  
public void siteStop() ^5?|Dj  
{ car|&b  
bStop = true; p/7'r  
for(int i=0;i<nStartPos.length;i++) ]mNsG0r6  
fileSplitterFetch.splitterStop(); Sd.Km a  
(~5]1S}F  
Slv:CM M  
} `)KGajB  
} MF*4E9Ue.  
//负责部分文件的抓取 L\bc R  
**FileSplitterFetch.java (n2_HePE  
*/ 3,*A VcQA  
package NetFox; vd$>nJ"  
h#)\K| qs  
B`3z(a92S  
import java.io.*; |f1^&97=+  
import java.net.*; 2>9..c  
s?k:X ~m  
SfrM|o  
public class FileSplitterFetch extends Thread { h -091N  
8I#^qr5  
Y,,Z47% E  
String sURL; //File URL hcYqiM@8>  
long nStartPos; //File Snippet Start Position d1t_o2  
long nEndPos; //File Snippet End Position +7 j/.R  
int nThreadID; //Thread's ID 4f ~q$Sf]<  
boolean bDownOver = false; //Downing is over l g ,%  
boolean bStop = false; //Stop identical Y$)y:.2#  
FileAccessI fileAccessI = null; //File Access interface <HS{A$]  
MYz!zI  
eAjR(\f>  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ZZ :*c"b:  
{ 0jxXUWO  
this.sURL = sURL; 55] MRv  
this.nStartPos = nStart; k 7@:e$7  
this.nEndPos = nEnd; ~q/~ u  
nThreadID = id; i|/G!ht^e  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 /|h+,]< >  
} YD9vWk \/  
0Ny +NE:6M  
)#hR}|  
public void run() @;{ZnRv14  
{ x{So  
while(nStartPos < nEndPos && !bStop) 7 TM-uA$  
{ k$#1T +(G  
[ z/G  
#u\~AO?h  
try{ z-"P raP  
URL url = new URL(sURL); S+mBVk"-~S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I1dOMu9  
httpConnection.setRequestProperty("User-Agent","NetFox"); d>#X+;-k  
String sProperty = "bytes="+nStartPos+"-"; g1y@z8Z{  
httpConnection.setRequestProperty("RANGE",sProperty); O ]-8 %  
Utility.log(sProperty); yiH;fK+x  
4"iI3y~Gw  
K)Z~ iBRM  
InputStream input = httpConnection.getInputStream(); At[SkG}b  
//logResponseHead(httpConnection); 9oP  
"qZTgCOY2  
FLkZZ\  
byte[] b = new byte[1024]; I.~=\%Z {  
int nRead; ,qV7$u  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) loBW#>  
{ )u]=^  
nStartPos += fileAccessI.write(b,0,nRead); ]+w 27!  
//if(nThreadID == 1) _ogN   
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %X%f0J  
} )7P>Hj  
i/!KUbt  
WHLTJ]OB  
Utility.log("Thread " + nThreadID + " is over!"); b{x/V9&|  
bDownOver = true; )/OIzbA3#  
//nPos = fileAccessI.write (b,0,nRead); [{& OcEf  
} *] >R  
catch(Exception e){e.printStackTrace ();} f/0k,~,*  
} B(eiRr3  
} YbZ?["S&  
d]sg9`  
YT)1_>*\  
//打印回应的头信息 Su +<mW  
public void logResponseHead(HttpURLConnection con) NQiu>Sg  
{  zNn  
for(int i=1;;i++) ,LLx&jS  
{ &Akw V-  
String header=con.getHeaderFieldKey(i); jSdC1,wR  
if(header!=null) @q@I(%_`  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); qzZ;{>_f  
Utility.log(header+" : "+con.getHeaderField(header)); oGbh *  
else "dYT>w  
break; BPOT!-  
} <@4V G  
} vYo~36  
~Xr[d07bC  
Zba<|C  
public void splitterStop() LCHw.  
{ K>\v<!%a  
bStop = true; 889^P`Q5  
} 8LuU2Lo  
2<AQ{ c  
{aopGu?i  
} W55kR.X6M  
&a\G,Ma  
:Z83*SPc  
/* z$/s` |]  
**FileAccess.java kaECjZ _&+  
*//文件访问(定位,写) o##!S6:A  
package NetFox; E=,fdyj.  
import java.io.*; Gu2=+?i?h  
2J3y 1  
U:PtRSdn!b  
public class FileAccessI implements Serializable{ G%}k_vi&q  
.+lx}#-#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 tTt}=hQpgX  
RandomAccessFile oSavedFile; aHitPPlq  
long nPos; O[|X=ZwR:l  
HA&hu /mw_  
,,S 2>X*L  
public FileAccessI() throws IOException :#N]s  
{ RH$YM `cZ  
this("",0); .8[uEQ_L  
} I-Hg6WtB  
;1r|Bx<5  
}`76yH^c  
public FileAccessI(String sName,long nPos) throws IOException \t=#MzjR  
{ .^ba*qb`{  
oSavedFile = new RandomAccessFile(sName,"rw"); 85A7YraL  
this.nPos = nPos; 5+(Cp3  
oSavedFile.seek(nPos); Tj6Czq=*%T  
} ZF<$6"4N  
tq*6]q8c>  
}Cb-7/  
public synchronized int write(byte[] b,int nStart,int nLen) @FRas00)|  
{ I(/*pa?m{  
int n = -1; ? Z2`f6;W4  
try{ j5~~%  
oSavedFile.write(b,nStart,nLen); 8\?H`NN  
n = nLen; Z:,`hW*A6  
} }+)q/]%  
catch(IOException e) h=kC3ot\  
{ 4`+R |"4  
e.printStackTrace (); =&: |a$C  
} g6?5  
N{a=CaYi+  
:{KpnJvd  
return n; og4mLoLA  
} F$YT4414  
# 3FsK  
O6\c1ha  
} A":cS }Ui  
JE eXoGKd  
))7CqN  
/* bq}`jP~#  
**SiteInfoBean.java #aE>-81SS&  
*/ mWMtz]M}  
package NetFox; 1>bNw-kz7  
*3fhVl=8^*  
CX]L'  
public class SiteInfoBean { gL7rX aj  
7oCY@>(f  
z)u\(W*\iA  
private String sSiteURL; //Site's URL 8rLhOA  
private String sFilePath; //Saved File's Path 6R#igLm  
private String sFileName; //Saved File's Name [z'jL'\4  
private int nSplitter; //Count of Splited Downloading File AU8sU?=  
8/"C0I (G  
qtz~Y~h|>  
public SiteInfoBean() q0nIJ(  
{//nSplitter的缺省值为5 }Am5b@g"$Y  
//default value of nSplitter is 5 R)=){SI:1)  
this("","","",5); M>{*PHze0  
} K d{o/R  
;O<-4$  
|[)pQGw  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) sy(.p^Z  
{ IJ7wUZp"  
sSiteURL= sURL; CFu^i|7o  
sFilePath = sPath; sH%Ts@Pl  
sFileName = sName; wZ_"@j<  
this.nSplitter = nSpiltter; onIZ&wrk  
8\+DSA  
`~N jBtQ  
} Q&w"!N  
l.BiE<&  
Ieh<|O,-C  
public String getSSiteURL() UsdMCJ&G  
{ 5eM{>qr}  
return sSiteURL; nL]eGC  
} 6$H`wDh#(&  
_Ec"[xW  
{"|la;*I  
public void setSSiteURL(String value) D&OskM60  
{ ({cWb:+r  
sSiteURL = value; D"IxQ2}k  
} )OK"H^}f  
3XDuo|(  
1aPFpo!  
public String getSFilePath() '#jZ`  
{ !Yz CK*av1  
return sFilePath; Rt@O@oDI  
} ` ^;J<l  
#9{2aRCJ  
b&RsxW7  
public void setSFilePath(String value) 9!ARr@ ;  
{ O.{  
sFilePath = value; 6lUC$B Y  
} 7/)0{B4U'  
$h5QLN  
J.]`l\  
public String getSFileName()  %Nx,ZD@  
{ 7t/Y5Qf  
return sFileName; X(Z(cY(  
} @S6@pMo,  
Z1] 4:  
#];ulDq  
public void setSFileName(String value) A f}o/g  
{ |<uBJ-5  
sFileName = value; g@Rs.Zq  
} 7JBr{3;eS  
{e0(M*u  
z|zEsDh;  
public int getNSplitter() Q(4~r+  
{  %\~U>3Q  
return nSplitter; . "7-f]!  
} G9@5 !-  
^ ~dC&!D  
3Z7gPU!H=  
public void setNSplitter(int nCount) >4os%T  
{ ,V{Bpr  
nSplitter = nCount; '-3K`[  
} "6v_<t`q"  
} n$E$@  
w}e_ 17A  
E%a&6W  
/* Z/ L%?zH  
**Utility.java K#VGG,h7Y  
*/ MeAY\V%G=o  
package NetFox; \C{Zqo,  
/)<kG(Z  
.kJu17!  
public class Utility { >;%LW} %  
b1%w+*d<z  
Y' 5X4Ks|  
public Utility() RMdU1@  
{ j]aIJbi  
G3h"Eo?>g  
p(9[*0.};  
} XV,ce~ro[  
IYa(B+nB)  
//线程睡眠 e*d lGK3l  
public static void sleep(int nSecond) A+FQmLS  
{ X1BqN+=@9  
try{ Dn#UcMO>W  
Thread.sleep(nSecond); O9N+<sU=X  
} nGur2}>n  
catch(Exception e) AoK;6je`K^  
{ P ,rLyx   
e.printStackTrace (); dux_v"Xl  
} Mhc5<~?  
} MM( ,D& Z  
G&4D0f  
//日志 -OnKvpeI  
public static void log(String sMsg) wNUcL*n  
{ d@zxgn7o  
System.err.println(sMsg); Yu9VtC1  
} XinKG< 3!  
Pon0(:#1  
KIKIag#  
public static void log(int sMsg) ^==Tv+T9U  
{ JOs kf(  
System.err.println(sMsg); {wO .nOB  
} <vu~EY0.  
} `, 4YPjk^  
2EO9IxIf  
ce719n$   
/* l_,6<wWp  
**TestMethod.java Mgu9m8 `J  
*/ ;ZkY[5  
package NetFox; [jEA|rd~}  
qLw^Qxo  
&3)6WD?:U  
public class TestMethod { p0}Yo8?OW  
o ,xy'  
ZVit] 3hd  
public TestMethod() ~{N#JOY}Z  
{ ///xx/weblogic60b2_win.exe z]=Ks_7  
try{ NdRE,HWd?$  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); q6x}\$mL  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); :`0,f?cE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P]L%$!g  
fileFetch.start(); $#wi2Ve=6b  
} O"_QDl<ya  
catch(Exception e){e.printStackTrace ();} Lmw)Ts>  
-w'g0/fD  
::3[H$  
} 4`7~~:W!M5  
#G\-ftA&  
Ki%)LQAg  
public static void main(String[] args) D%=&euB  
{ ~bis!(}p-  
new TestMethod(); >4HB~9dKU  
} cBHUa}:  
} K)h<#F  
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