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http断点续传简单实现(java)

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/* 7KlS9x2  
**SiteFileFetch.java [a[.tR38e  
*/  v[+ ]  
package NetFox;  {S$61ut  
import java.io.*; @r*w 84  
import java.net.*; Q{:=z6&  
U(rY,4'  
UID0|+%Y  
public class SiteFileFetch extends Thread { gtwUY$  
{y%cTuC=  
@d1YN]ede  
SiteInfoBean siteInfoBean = null; //文件信息Bean 3Jh!YzI8  
long[] nStartPos; //开始位置 >|1$Pv?  
long[] nEndPos; //结束位置 r?$ V;Z  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 QnTKo&|9  
long nFileLength; //文件长度 ' 5xvR G  
boolean bFirst = true; //是否第一次取文件 t}wwRWo2?f  
boolean bStop = false; //停止标志 M->BV9  
File tmpFile; //文件下载的临时信息 L']"I^( N  
DataOutputStream output; //输出到文件的输出流 &`%J1[dy  
U0ZPY )7k  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) s J{J@/5  
public SiteFileFetch(SiteInfoBean bean) throws IOException Wi+}qO  
{ F^Y%Q(Dd7w  
siteInfoBean = bean; eq6>C7.$  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); VxAG= E  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); m|]:oT`M  
if(tmpFile.exists ()) Ju@8_ ?8=  
{ V~ q b2$  
bFirst = false; [aF"5G  
read_nPos(); H{et2J<H  
} k4-S:kVo  
else HD YWDp  
{ I&wJK'GM`  
nStartPos = new long[bean.getNSplitter()]; <;lwvO  
nEndPos = new long[bean.getNSplitter()]; ey@{Ng#  
} c\le8C3  
i?:#lbw_  
@:Emmzucv|  
t\XA JU  
} re)7h$f}  
E"zC6iYZ;  
{` ByZB  
public void run() \#!B*:u  
{ ,}:}"cl  
//获得文件长度 *_sSM+S  
//分割文件 <%N*IE"q  
//实例FileSplitterFetch n/ZX$?tKAK  
//启动FileSplitterFetch线程 -A^o5s  
//等待子线程返回 u10;qYfL8o  
try{ VVw5)O1'  
if(bFirst) EYRg,U&'  
{  :!/ (N  
nFileLength = getFileSize(); U8a5rF><  
if(nFileLength == -1) nIWY<Z"  
{ 6&;h+;h  
System.err.println("File Length is not known!"); D!V~g72j  
} `4-N@h  
else if(nFileLength == -2) <8ih >s(C  
{ U'LPaf$O  
System.err.println("File is not access!"); kD me>E=  
} t\WU}aKML  
else ~~3*o  
{ %uz6iQaq]X  
for(int i=0;i<nStartPos.length;i++) 9I[k3  
{ NXMZTZpB7  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); O$7cN\Z  
} zSagsH |W  
for(int i=0;i<nEndPos.length-1;i++) *Ksk1T+>  
{ %)w7t[A2D  
nEndPos = nStartPos[i+1]; AAF']z<4_"  
} B:VGa<lx5  
nEndPos[nEndPos.length-1] = nFileLength; ](^FGz  
} &S39SV  
} H6hhU'Kxf8  
9\VV++}s>o  
>mj WC) U  
//启动子线程 d*dPi^JjC  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 7l4}b^>/`  
for(int i=0;i<nStartPos.length;i++) QIfP%,LT  
{ 88VI _<  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /*(&Dmt>  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), jN!VrRA  
nStartPos,nEndPos,i); j dkqJ4&i  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %6la@i  
fileSplitterFetch.start(); u s8.nL/  
} nG%<n  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), )4RSo&9p`  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); p2 !w86 F  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", >*EJ6FPO  
nEndPos = " + nFileLength); gnadx52FP  
// fileSplitterFetch[nPos.length-1].start(); X!6$<8+1OV  
deEc;IAo  
JfRLqA/  
//等待子线程结束 ?DE{4Ti/[  
//int count = 0; Myf2"\}  
//是否结束while循环 ,0eXg  
boolean breakWhile = false; q ,+29  
; o(:}d  
IdCE<Oj\  
while(!bStop) R[l~E![!j  
{ uR.`8s|  
write_nPos(); 4|UtE<<b  
Utility.sleep(500);  &\ K  
breakWhile = true; }L @~!=q*  
Bkg./iP5x  
-b)3+#f  
for(int i=0;i<nStartPos.length;i++)  `7oYXk  
{ /m4Y87  
if(!fileSplitterFetch.bDownOver) a1EQ.u  
{ w~3z) ;  
breakWhile = false; "5v^6R9e  
break; @O|`r(le  
} :`c@&WF8  
} ,u9 >c*Ss\  
if(breakWhile) })j N 8px  
break; <B'PB"R3y  
+U iJWO  
= toU?:.  
//count++; )6%a9&~H  
//if(count>4) (+}44Ldt  
// siteStop(); NZ?dJ"eq7  
} UgD)O:xaU  
^\r{72!y  
@k\,XV`T~t  
System.err.println("文件下载结束!"); wRZS+^hx  
} 'wWuR@e#&  
catch(Exception e){e.printStackTrace ();} hxt;sQAo{  
} xEv?2n@A  
Cq[Hh#q  
4ves|pLET  
//获得文件长度 j=c< Lo`  
public long getFileSize() $W9dUR0  
{ Ya-GDB;L  
int nFileLength = -1; LYiIJAZ.  
try{ D~M*]&  
URL url = new URL(siteInfoBean.getSSiteURL()); |E;+j\   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0U !&|i\  
httpConnection.setRequestProperty("User-Agent","NetFox"); -j@IDd7  
GiKhdy  
""m/?TZq'  
int responseCode=httpConnection.getResponseCode(); ~%h&ELSw  
if(responseCode>=400) J ~KygQ3%  
{ ! %B-y 9\  
processErrorCode(responseCode); oi8M6l  
return -2; //-2 represent access is error ge1U1o  
} ce*?crOV  
Kw2]J)TO  
L* ScSxw  
String sHeader; p.H`lbVY  
$j \jT  
]=59_bkD:s  
for(int i=1;;i++) "1`w>(=  
{ %-B wK  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); yZ]?-7  
//Utility.log(in.readLine()); [[xnp;-;  
sHeader=httpConnection.getHeaderFieldKey(i); I:0dz:T7*  
if(sHeader!=null) a-AA$U9hj  
{ *$3p3-  
if(sHeader.equals("Content-Length")) V{ ~~8b1E  
{ c7R&/JV  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); z2Z}mktP  
break; m_FTg)_=  
} 93ggCOaYA  
} c[$i )\0  
else *_]fe&s=%  
break; $.31<@T7  
} 'v=BAY=Ef  
} r%>EiHpCU  
catch(IOException e){e.printStackTrace ();} vu&ny&=`  
catch(Exception e){e.printStackTrace ();} l<'}`  
$`R=Q  
Vy^mEsQC+h  
Utility.log(nFileLength); @1U6sQ  
[z6P]eC7  
:Zo^Uc:*w  
return nFileLength; eu?P6>urA  
} {Z1-B60P  
g|h;*  
rB|4  
//保存下载信息(文件指针位置) %NfH`%`  
private void write_nPos() !& >LLZ  
{ r{_1M>F D!  
try{ >GzH_]  
output = new DataOutputStream(new FileOutputStream(tmpFile)); T'9M  
output.writeInt(nStartPos.length); !1@o Z(  
for(int i=0;i<nStartPos.length;i++) c(Fo-4K  
{ lE!.$L*k  
// output.writeLong(nPos); :9(w~bB9$  
output.writeLong(fileSplitterFetch.nStartPos); _@VKWU$$  
output.writeLong(fileSplitterFetch.nEndPos); &B++ "f  
} db}lN  
output.close(); &vIj(e9Y  
} >5zD0!bA  
catch(IOException e){e.printStackTrace ();} ABL5T-*]  
catch(Exception e){e.printStackTrace ();} 7M_GGjP  
} F!2VTPm9z  
YG)7+94  
,u!_mV  
//读取保存的下载信息(文件指针位置) \`%#SmQF  
private void read_nPos() 4VkJtu5  
{ l E* .9T  
try{ Ih;D-^RQ  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); KXUJ*l-5  
int nCount = input.readInt(); R;uP^  
nStartPos = new long[nCount]; 6Q&i=!fQ  
nEndPos = new long[nCount]; " Lh XR  
for(int i=0;i<nStartPos.length;i++) |/Y!R>El  
{ 238z'I+$G/  
nStartPos = input.readLong(); VTi; y{  
nEndPos = input.readLong(); @&9< )1F  
} 84s:cO  
input.close(); 2P{! n#"  
} \lyHQ-gWhc  
catch(IOException e){e.printStackTrace ();} = N:5#A  
catch(Exception e){e.printStackTrace ();} .TNJuuO  
} 6)FM83zk)K  
pBn;:  
P(3$XMx  
private void processErrorCode(int nErrorCode) n@S|^cH  
{ ^ ,[gO#hgz  
System.err.println("Error Code : " + nErrorCode); %WYveY  
} A-eCc#I  
=,&{ &m)  
e'=#G$S?g  
//停止文件下载 db3.X~Cn#s  
public void siteStop() 5"+;}E|q  
{ dbF9%I@  
bStop = true; 5j _[z|W2  
for(int i=0;i<nStartPos.length;i++) J`wx72/-ZW  
fileSplitterFetch.splitterStop(); U;gy4rj  
k_Lv\'Ok  
HD z"i  
} 9'KOc5@l^  
} =S\pI  
//负责部分文件的抓取 lg 1r]  
**FileSplitterFetch.java 8P&z@E{y  
*/ Qr?(2t#  
package NetFox; 0.1?hb|p5T  
6*I=% H|  
t3!~=U  
import java.io.*; nzU0=w}V  
import java.net.*; 59?$9}ob  
HLh]*tQG  
lvUWs  
public class FileSplitterFetch extends Thread { ESe$6)P  
RVpo,;:  
C4|79UG>s  
String sURL; //File URL j"&Oa&SH  
long nStartPos; //File Snippet Start Position ,ZnL38GW  
long nEndPos; //File Snippet End Position lnV!Xuf  
int nThreadID; //Thread's ID cQ0+kX<  
boolean bDownOver = false; //Downing is over Tcq@Q$H  
boolean bStop = false; //Stop identical PW9tZx#  
FileAccessI fileAccessI = null; //File Access interface lW]&a"1$  
ZZ>(o d!B  
u#3Cst8Y  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException vQ{mEaH  
{ )xTu|V   
this.sURL = sURL; R5<:3tk=X  
this.nStartPos = nStart; |lVi* 4za%  
this.nEndPos = nEnd; vnX~OVz2  
nThreadID = id; 8=mx5Gwz-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Nm3CeU  
} jW}hLjlN  
CR-2>,*a9  
F5\{`  
public void run() XZ/cREz^s  
{ ^5-SL?E  
while(nStartPos < nEndPos && !bStop) /)r[}C0   
{ Pa ^_ s  
Gk|T1%  
#jw%0H;l]  
try{ quFNPdP  
URL url = new URL(sURL); q]y{ 4"=5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); :/;;|lGw  
httpConnection.setRequestProperty("User-Agent","NetFox"); eW[](lGWM  
String sProperty = "bytes="+nStartPos+"-"; )U{IQE;T#  
httpConnection.setRequestProperty("RANGE",sProperty); \Zn~y--Z  
Utility.log(sProperty); Ystd[  
hTQ]xN)  
")W5`9  
InputStream input = httpConnection.getInputStream(); y"ms;w'z  
//logResponseHead(httpConnection); u/5)Yx+5_  
DF"*[]^[  
p Acu{5#7  
byte[] b = new byte[1024]; ~B`H5#  
int nRead; 1*B'o<?P1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) .L_ Hk  
{ =AeOkie  
nStartPos += fileAccessI.write(b,0,nRead); No]#RvEd3  
//if(nThreadID == 1) fc%C!^7  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d ewN\  
} -nB. .q  
gq+#=!(2  
<{.pYrn  
Utility.log("Thread " + nThreadID + " is over!"); H`T}k+e2-N  
bDownOver = true; |PLWF[+t8  
//nPos = fileAccessI.write (b,0,nRead); "T6s;'k  
} p%e/>N.P  
catch(Exception e){e.printStackTrace ();} a,[NcdG  
} A)kdY!}  
} g=S|lVQm  
prVqV-S6TY  
;oRgg'k<  
//打印回应的头信息 w#;y  
public void logResponseHead(HttpURLConnection con) SdJkno  
{ t},71Ry  
for(int i=1;;i++) <J^94-[CF  
{ DXfQy6k'  
String header=con.getHeaderFieldKey(i); wPpern05  
if(header!=null) 3:gF4(.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0y/P  
Utility.log(header+" : "+con.getHeaderField(header)); QH6_nZY  
else ,uS}wJAX  
break; !]#;'  
} E1|:t$>Ld  
} r5uX?^mJ0  
.Kk'N  
.vpx@_;]9  
public void splitterStop() LLwC*)#  
{ 3 n1 > +8  
bStop = true; }/F9(m  
} ]#J-itO  
|f+fG=a67V  
=M34 HPG  
} Qh4Z{c@  
^+9i~PjL  
8' +I8J0l  
/* C0'_bTfB  
**FileAccess.java D;X/7 p|>  
*//文件访问(定位,写) \xOv9(  
package NetFox; l`*R !\  
import java.io.*; 'k9 1;T[  
2;YL+v2  
/3 d6Og  
public class FileAccessI implements Serializable{ h=ko_/<  
r1|;V~ a$~  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 bcFZ ~B  
RandomAccessFile oSavedFile; THnZbh4#)  
long nPos; P64< O 5l/  
mvGj !'  
7gT^ZL  
public FileAccessI() throws IOException &fgfCZz'  
{ Tw9?U,]  
this("",0); -&r A<j  
} XE : JL_  
+L#Q3}=s  
Bfr$&?j#  
public FileAccessI(String sName,long nPos) throws IOException !o8(9F  
{ |&rxDf}W  
oSavedFile = new RandomAccessFile(sName,"rw"); Np R&`]  
this.nPos = nPos; ykG^(.E  
oSavedFile.seek(nPos); YRJw,xl  
} b`DPf@p^kc  
~.8p8\H  
bF? {  
public synchronized int write(byte[] b,int nStart,int nLen) O.OSLezTQ  
{ &e1(|qax  
int n = -1; R}\n @X*  
try{ z4*`K4W  
oSavedFile.write(b,nStart,nLen); k54Vh=p  
n = nLen; 1WLaJ%Fv  
} :%"$8o*0W  
catch(IOException e) psE&Rx3)  
{ !"N-To-c  
e.printStackTrace (); UWq[K&vQZ  
} T &kr IZw  
R]Pv=fn  
M`.v/UQn  
return n; {~eVZVv  
} %n>*jFC  
L2^M#G@t  
i 9wk)  
} mEDi'!YE"  
l*<RKY8  
I?%iJ%  
/* +`Ypc  
**SiteInfoBean.java ?DKwKt  
*/ ?ZT+4U00U  
package NetFox; ($Ck5`_MK  
y4 ~;H{!  
S%k](\7!  
public class SiteInfoBean { j43-YdCJ  
@j?)uJ0Q  
,.&y-?  
private String sSiteURL; //Site's URL jsnk*>j  
private String sFilePath; //Saved File's Path fkK42*U@r  
private String sFileName; //Saved File's Name \Dr?}D  
private int nSplitter; //Count of Splited Downloading File ".T&nS[z  
(uskVK>L  
@If ^5s;z  
public SiteInfoBean() 8^6dK  
{//nSplitter的缺省值为5 ^K n{L  
//default value of nSplitter is 5 xdd;!HK,  
this("","","",5); XKepk? E  
} Dg2=;)"L  
khtYn.eaL  
\t\ZyPxn  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) uGH>|V9'c  
{ %,[p[`NRYR  
sSiteURL= sURL; H8'_.2vwX  
sFilePath = sPath; QAmb_:^"d  
sFileName = sName; k874tD  
this.nSplitter = nSpiltter; %vFoTu)2  
mu}T,+9\  
t^-yK;`?q:  
} \w\{x0u  
a}MSA/K(  
^+zhzfJ  
public String getSSiteURL() +Q6}kbDI  
{ XhEd9>#  
return sSiteURL; ;;g'C*_  
} j^'op|l  
/K<.$B8  
?oO<PR}y  
public void setSSiteURL(String value) n; fUwon  
{ 9>na3ISh  
sSiteURL = value; +Pm yFJH  
} (r+#}z}  
?Wz rv&E2  
|VRzIA4M\  
public String getSFilePath() O4i5 fVy{  
{ }+Ne)B E  
return sFilePath; jLu`DKB  
} K}p!W"!o  
W4~:3 Sk  
Ot#O];3  
public void setSFilePath(String value)  iI(7{$y  
{ 1"5-doo  
sFilePath = value; dy%#E2f  
} ypK1 sw  
NWq>Z!x`  
l3C%`[MB  
public String getSFileName() s9'lw'  
{ Mk~]0d  
return sFileName; "]M]pR/j  
} PA(XdT{  
Vx6/Rehj  
B5Y 3GWhrx  
public void setSFileName(String value) 8V$:th('  
{ ,AO]4Ec  
sFileName = value; (d2|r)O  
} RiX~YL eM  
u79,+H@ep  
ZH<:YOQ  
public int getNSplitter() )|?s!rw +  
{ *6trK`tx^  
return nSplitter; /X_g[*]?  
} q`8M9-~  
H=j&uv8  
D L0i  
public void setNSplitter(int nCount) J<4 egk4  
{ oSOO5dk:z  
nSplitter = nCount; xF4>D!T%8  
} ,>rr|O  
} Rr|&~%#z  
{:;599l  
*$I5_A8,.  
/* D+ )R_  
**Utility.java =E?!!EIq.  
*/ |E YJbL;1%  
package NetFox; C \B&'+uR  
LK1 r@  
VdZmrq;?/  
public class Utility { 1k *gbXb  
Uz`K#Bz   
NBUSr}8|  
public Utility() _*I@ J/  
{ Uczb"k5  
_*SA_.0  
y.l`NTT] <  
} "#a_--"k9  
:bhpYEUMx  
//线程睡眠 ^K#PcPF-j  
public static void sleep(int nSecond) 9{;cp?\)M  
{ +v`?j+6z  
try{ lo%:$2*'p  
Thread.sleep(nSecond); nK" XyZ&  
} u&!QP4$"z  
catch(Exception e) 2$MIA?A"Y  
{ f;u<r?>Z  
e.printStackTrace (); pS3TD"p  
} MifPZQ  
} \[Dxg`;4  
IU8/B+hM~  
//日志 x! A.**  
public static void log(String sMsg) >Bj+!)96q  
{ _djr>C=H"  
System.err.println(sMsg); vy t$  
} 1,tM  
f"=1_*eH  
s:6pPJL  
public static void log(int sMsg) py9HUyr5eZ  
{ 'ow`ej  
System.err.println(sMsg); S|{'.XG  
} *[-% .=[7  
} >>ncq$  
lAxbF  
0 s-IW  
/* nnV(MB4z1  
**TestMethod.java VZ`L-P$AF  
*/ ~qG`~/7  
package NetFox; uK:?6>H  
=lzRx%tm  
hpxqL%r  
public class TestMethod { aP%2CP~_P  
rHir> p  
| Vtd !9  
public TestMethod() m@r+M"!R  
{ ///xx/weblogic60b2_win.exe ]pZxbs&Vb  
try{ \M H\!  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); RGw=!0V  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); [/s^(2%  
SiteFileFetch fileFetch = new SiteFileFetch(bean); vgc #IEx@  
fileFetch.start(); kIb)I(n  
} 8Rgvb3u  
catch(Exception e){e.printStackTrace ();} (o!v,=# 6{  
Hqel1J  
;^q@w  
} j{i3lGaN  
7gLN7_2  
: "|M  
public static void main(String[] args) V'XmMn)!  
{ T+OQa+E@P  
new TestMethod(); \,-t]$9  
} e;y\v/A  
} yEnurq%J  
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