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http断点续传简单实现(java)

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/* A@)Q-V8*9s  
**SiteFileFetch.java i\ X3t5  
*/ dX@ic,?  
package NetFox; ;M4[Liw~O  
import java.io.*; c&',#.9  
import java.net.*; R^o535pozc  
nH6SA1$kW  
Sq ]gU  
public class SiteFileFetch extends Thread { BO w[*hM  
76 )"uqv1x  
e8^/S^ =&d  
SiteInfoBean siteInfoBean = null; //文件信息Bean -oyA5Y x0  
long[] nStartPos; //开始位置 }3X/"2SW^  
long[] nEndPos; //结束位置 8T T#b?d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Cd 2<r6i  
long nFileLength; //文件长度 ;Jg$C~3tf  
boolean bFirst = true; //是否第一次取文件 \2 N;V E  
boolean bStop = false; //停止标志 %bN{FKNN  
File tmpFile; //文件下载的临时信息 LkS tU)  
DataOutputStream output; //输出到文件的输出流 eTvjo(Lvx  
vu\W5M  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) +u0of^}=  
public SiteFileFetch(SiteInfoBean bean) throws IOException r+E!V'{C  
{ |xFA}  
siteInfoBean = bean; ~rdS#f&R2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z}u`45W+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 1LRP R@b^  
if(tmpFile.exists ()) [,AFtg[  
{ S*h^7?Bu  
bFirst = false; if|5v^/  
read_nPos(); 9=MNuV9/s  
} }_zN%Tf~  
else -@"3`uv"  
{ [+dCA  
nStartPos = new long[bean.getNSplitter()]; =JzzrM|V*  
nEndPos = new long[bean.getNSplitter()]; E4892B:`  
} ?96r7C|  
~&D =;M/  
`mz}D76~#  
C?gqX0[ q  
} HJ 7A/XW  
8$ _{R!x  
]?@ [Ny=0  
public void run() DPxx9lN_rx  
{ ;7:} iKU  
//获得文件长度 ~ O#\$u  
//分割文件 SQ4^sk_!  
//实例FileSplitterFetch z:f&k}(  
//启动FileSplitterFetch线程  g]?pY  
//等待子线程返回 zl :by?  
try{ 6LCtWX  
if(bFirst) p7Wt(A  
{ M> WWP3  
nFileLength = getFileSize(); ) Y)_T&O  
if(nFileLength == -1) q=5aHH% |  
{ +\Jo^\  
System.err.println("File Length is not known!"); it\$Pih]  
} O~V^]   
else if(nFileLength == -2) q< q IT  
{ KMIe%2:b5  
System.err.println("File is not access!"); >=;-:  
} g:Qq%'  
else B1 }-   
{ gPk,nB  
for(int i=0;i<nStartPos.length;i++) #ay/VlD@  
{ NgyEy n \  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); QvZ"{  
} FJtmRPP[r  
for(int i=0;i<nEndPos.length-1;i++) _`? cBu`  
{  (yP1}?  
nEndPos = nStartPos[i+1]; d9v66mpJM  
} <?7qI85OT  
nEndPos[nEndPos.length-1] = nFileLength; IsI5c  
} yHw @Z  
} m)p|NdTZc8  
D}y W:Pi'  
ZDmL?mC  
//启动子线程 y7F |v8bq  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 90W= v*  
for(int i=0;i<nStartPos.length;i++) }[JB%  
{ D8L5t<^1R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D2&d",%&f  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), xcW\U^1d  
nStartPos,nEndPos,i); K{DC{yLu  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); N=1ue`i  
fileSplitterFetch.start(); ZEI)U, I.  
} C5dM`_3L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c%pf,sm'  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $~FZJ@qa  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Hj{.{V  
nEndPos = " + nFileLength); 8*0QVFn$  
// fileSplitterFetch[nPos.length-1].start(); Bp7p X  
iuY,E  
xS1n,gTA  
//等待子线程结束 USyc D`  
//int count = 0; )v;O2z  
//是否结束while循环 B=d< L^  
boolean breakWhile = false; I+kAy;2  
S~aWun  
K-k!':K:  
while(!bStop) <Tgy$Hm  
{ ulsU~WW7r  
write_nPos(); 8<Iq)A]'Z  
Utility.sleep(500); % vUU Fub  
breakWhile = true; I9qZE=i  
_rYW|*cIF  
s;TB(M~i[  
for(int i=0;i<nStartPos.length;i++) r!Dk_| Cd  
{ 8C3oi&av/{  
if(!fileSplitterFetch.bDownOver) -yqgs>R(d  
{ A3/[9}(U  
breakWhile = false; gDU!dT  
break; @lj|  
} `qhT  
} <h:xZtz  
if(breakWhile) zr?s5RS  
break; 7!AyLw  
j<(E %KN3  
0V<kpC,4  
//count++; kMVr[q,MEq  
//if(count>4) O`y3H lc  
// siteStop(); GLO3v. n;  
} -b^dK)wR~  
>} 2C,8N  
ys=} V|  
System.err.println("文件下载结束!"); bfA>kn0C  
} Qg/FFn^Kg*  
catch(Exception e){e.printStackTrace ();} l0,VN,$Yl  
} y5eEEG6  
Un K7&Uo  
a 4ViVy  
//获得文件长度 ;iiCay37F  
public long getFileSize() h_4*?w  
{ p48enH8CO  
int nFileLength = -1; q3#[6!  
try{ nvndgeSy  
URL url = new URL(siteInfoBean.getSSiteURL()); WCsf_1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); GrG'G(NQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); gV.?Myy  
^o5;><S]  
rB".!b  
int responseCode=httpConnection.getResponseCode(); 1+*sEIC"  
if(responseCode>=400) 5/nL[4Z  
{ 2ul8]=  
processErrorCode(responseCode); HU>>\t?d  
return -2; //-2 represent access is error m)L50ot:/  
} ."ZG0Zg  
rNV3-#kU  
5c::U=  
String sHeader; *90dkJZ.  
_33 b %  
b_TI_  
for(int i=1;;i++) l jK?2z>  
{ `]W9Fj<1j  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :-jbIpj'  
//Utility.log(in.readLine()); H14Q-2U1xa  
sHeader=httpConnection.getHeaderFieldKey(i); a9e0lW:=c  
if(sHeader!=null) >G|RVB  
{ B$rhsK%  
if(sHeader.equals("Content-Length")) x"q]~u<rB  
{ H-pf8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); K^<?LXJF  
break; H[.)&7M\  
} *xxk70Cb  
} ^Saf z8-3o  
else /lECgu*#69  
break; K[iAN;QCe%  
} ]|!|3lQ  
} } iKjef#J  
catch(IOException e){e.printStackTrace ();} ~B{08%|oK  
catch(Exception e){e.printStackTrace ();} 7<WUj K|  
A2gFY}  
j?u1\<m  
Utility.log(nFileLength); ;7s^slVzF  
_{'[Uf/l  
+m./RlQ{  
return nFileLength; jz" >Kh.}  
} 8zHx$g  
v K{2  
t,De/L  
//保存下载信息(文件指针位置) vNjc  
private void write_nPos() [z!m  
{ r2#G|/=@  
try{ lUjZ=3"'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); L~PiDQr?r  
output.writeInt(nStartPos.length); {g nl6+j  
for(int i=0;i<nStartPos.length;i++) QP\:wi  
{ #$W5)6ch  
// output.writeLong(nPos); 1"CWEL`i  
output.writeLong(fileSplitterFetch.nStartPos); ?rOj?J9  
output.writeLong(fileSplitterFetch.nEndPos); `WH$rx!  
} 2+y wy^  
output.close(); i ed 1+H  
} >g !Z|ju  
catch(IOException e){e.printStackTrace ();} b/[X8w'VP  
catch(Exception e){e.printStackTrace ();} 'sZGLgT;m  
} -KC@M  
@}6<,;|DQ  
H,TApF89A  
//读取保存的下载信息(文件指针位置) "=DQ {(L  
private void read_nPos() WwsNAJ  
{ 3\RD %[}  
try{ ;O)*!yA(GG  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); e^ N~)Nlj  
int nCount = input.readInt(); #"-_~  
nStartPos = new long[nCount]; KH#z =_  
nEndPos = new long[nCount]; JfkEJk<  
for(int i=0;i<nStartPos.length;i++) ~9o@1TO:v  
{ _5S0A0  
nStartPos = input.readLong(); KC}G_"f.$  
nEndPos = input.readLong(); gnZ#86sO  
} J=Kv-@I>E  
input.close(); Mw,]Pt6~i  
} s/@uGC0>  
catch(IOException e){e.printStackTrace ();} pBe1:  
catch(Exception e){e.printStackTrace ();} dCM &Yf}K  
} MD$W;rk(Hn  
mRAt5a#is  
k(RKAFjY  
private void processErrorCode(int nErrorCode) K@e2%hk9x  
{ HYO/]\al  
System.err.println("Error Code : " + nErrorCode); +)yoQRekX  
} [nHN@ p|  
v\bWQs1  
axmq/8X  
//停止文件下载 l4T[x|')M  
public void siteStop() 1v:Ql\^cT  
{ 4I&(>9 @z<  
bStop = true; YSxr(\~j   
for(int i=0;i<nStartPos.length;i++) 8 !:2:  
fileSplitterFetch.splitterStop(); &i3SB[|  
G HQ~{  
GmNCw5F  
} e~gNGr]L/  
} ^`#7(S)a/  
//负责部分文件的抓取 b0'}BMJ  
**FileSplitterFetch.java q 1xSylE  
*/ ;iYCeL(  
package NetFox; .BxQF  
6, j60`f)  
<;#gcF[7>  
import java.io.*; Qa/1*Mb  
import java.net.*; Da)p%E>Q  
-flcB|I`  
f {2UL ?y  
public class FileSplitterFetch extends Thread { +a,#BSt  
#QsJr_=  
Hc8^w6S1@  
String sURL; //File URL 82 |^o  
long nStartPos; //File Snippet Start Position "Ia.$,k9  
long nEndPos; //File Snippet End Position J#H,QYnf(L  
int nThreadID; //Thread's ID yz0#0YG7  
boolean bDownOver = false; //Downing is over 5-0&`,  
boolean bStop = false; //Stop identical 8fi'"  
FileAccessI fileAccessI = null; //File Access interface OU` !c[O  
E8PwA.  
*MfH\X379  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException mEYfsO  
{ P%&|?e~D^  
this.sURL = sURL; 9[\do@  
this.nStartPos = nStart; 7./WS,49  
this.nEndPos = nEnd; I/upiqy  
nThreadID = id; aC' 6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 g:~q&b[q6  
} v B~VJKD  
!oi {8X@  
9ec?L  
public void run() ye(av&Hn  
{ %VB4/~ "  
while(nStartPos < nEndPos && !bStop) Ys_L GfK  
{ o1\N)%  
4sSw7`  
_l] 0V g`  
try{ D]fgBW-  
URL url = new URL(sURL); .nEMd/pX  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ar~<l2,{r  
httpConnection.setRequestProperty("User-Agent","NetFox"); d]K8*a%[-  
String sProperty = "bytes="+nStartPos+"-"; ,Gbc4x  
httpConnection.setRequestProperty("RANGE",sProperty); Ha]vG@?+  
Utility.log(sProperty); 416}# Mk  
Pbbi*&i  
}LS.bQKqi,  
InputStream input = httpConnection.getInputStream(); ?`Mk$Y%my  
//logResponseHead(httpConnection); |Wck-+}U  
,_V/W'  
z@ZI$.w  
byte[] b = new byte[1024]; J"h2"$v,  
int nRead; 7g Ou|t  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) pk'd& .  
{ uj\&-9gEi  
nStartPos += fileAccessI.write(b,0,nRead); 4VvE(f  
//if(nThreadID == 1) Y5ei:r|^  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); cGo_qR/B(>  
} hFtjw6  
_d7;Z%  
yYe>a^r4R  
Utility.log("Thread " + nThreadID + " is over!"); y+$vHnS/jC  
bDownOver = true; wPYeKOh'  
//nPos = fileAccessI.write (b,0,nRead); "fv+}'  
} mHW%^R=  
catch(Exception e){e.printStackTrace ();} x]hG2on!  
} vMX\q  
} ~ m vv :u  
3rZPVR$))  
GNwFB)?j  
//打印回应的头信息 /EQ^-4yr  
public void logResponseHead(HttpURLConnection con) !"/"Mqs3$  
{ Zw4%L?   
for(int i=1;;i++) pHoxw|'Y  
{ FeZWS>N  
String header=con.getHeaderFieldKey(i); )#4(4 @R h  
if(header!=null) v5 p`=Z@%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); (p' /a.bn  
Utility.log(header+" : "+con.getHeaderField(header)); Hr]  
else FmF[S&gFRs  
break; uF3{FYM{I  
} -sf[o"T,j  
} Jk`l{N  
"g"%7jK  
/_expSPHl  
public void splitterStop() v`'Iew }  
{ h(~of (  
bStop = true; GU1cMe  
} }h/7M  
Ap"%%D^{:  
@o}J)  
} <o|k'Y(-  
"5$p=|  
L`O7-'`  
/* #/9Y}2G|]  
**FileAccess.java ? YIe<  
*//文件访问(定位,写) bx6=LK  
package NetFox; 6W]C`  
import java.io.*; h<'tQGC  
Kx[+$Qt  
zmuR n4Nv  
public class FileAccessI implements Serializable{ MYxuQ|w  
DuAix)#FN9  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 pnuwj U-  
RandomAccessFile oSavedFile; %0vsm+XQ0E  
long nPos; I:al[V2g  
.bV^u  
*GhV1# <  
public FileAccessI() throws IOException FW3E UC)P  
{ Xfb-< Q0A  
this("",0); i 8cmT+}>  
} $%&OaAg  
 RZqMpW  
Xa"I  
public FileAccessI(String sName,long nPos) throws IOException C[ KMaB  
{ &0ymAf5R  
oSavedFile = new RandomAccessFile(sName,"rw"); H8@z/  
this.nPos = nPos; *U\`HUW  
oSavedFile.seek(nPos); +g1+,?cU  
} >#T?]5Z'MF  
(bNoe(<qU  
FL$S_JAw  
public synchronized int write(byte[] b,int nStart,int nLen) 1B 0[dK2N  
{ n#?y;Y\  
int n = -1; #IqRu:csp  
try{ V!@6Nv  
oSavedFile.write(b,nStart,nLen); FSkX95  
n = nLen; VggSDb  
} J5f}-W@  
catch(IOException e) KxhWZ3  
{ UpQda`rb  
e.printStackTrace (); cV`NQt<W  
} v$;URF%^  
a 7b1c!  
U: <  
return n; J*%IvRg  
} 3F6A.Ny  
%\'G2  
 l]   
} X*Q<REDB  
u Vv %k5  
G_k_qP^:  
/* z -]ND  
**SiteInfoBean.java hVZS6gU,x  
*/ 7a/ BS(kq<  
package NetFox; o~xGE6A*"  
d,'gh4C  
4] u\5K-  
public class SiteInfoBean { jQfnc:'  
NSzTl-eS  
]R09-s 0$7  
private String sSiteURL; //Site's URL 3:OqD~,zy  
private String sFilePath; //Saved File's Path ka`}lR  
private String sFileName; //Saved File's Name p~(STHDe#  
private int nSplitter; //Count of Splited Downloading File `oO*ORq&  
Ak}`zIo  
-\Z`+kY?p  
public SiteInfoBean() Qo(<>d  
{//nSplitter的缺省值为5 X VH( zJ  
//default value of nSplitter is 5 FId,/la  
this("","","",5); NJ$Qm.S  
} f& Sovuuh  
#z*,-EV|  
3^)c5kcI  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) e+ m(g  
{ 3Zpq#  
sSiteURL= sURL; \mt Y_O  
sFilePath = sPath; `Xi)';p  
sFileName = sName; ),%@X  
this.nSplitter = nSpiltter; mSEX?so=[  
LS-_GslE7\  
F+D e"^As  
} e!k4Ij-]  
YQ1rS X3  
%r(qQM.Pl  
public String getSSiteURL() SapVS*yx@  
{ Cs vwc%  
return sSiteURL; X7?14W  
} -2C^M> HZ  
r"VNq&v]9  
gla'urb[i|  
public void setSSiteURL(String value) i DsY 5l  
{ G}dq ft5"  
sSiteURL = value; &pv* TL8  
} \SJX;7 ST  
3?+t%_[  
( ~JtKSq%  
public String getSFilePath() XE;' K`%  
{ Q} -YD.bx3  
return sFilePath; TTo?BVBK  
}  {yxLL-5c  
oy=ej+:  
+R 8dy  
public void setSFilePath(String value) m&MZn2u[4i  
{ kFfNDM#D  
sFilePath = value; zvv/|z2(r  
} x_(K%0+Ca  
k~QmDq  
A' n7u'6=  
public String getSFileName() W$z^U) |t  
{ NR^3 1&}It  
return sFileName; F*4G@)  
} zRR^v&.9K  
ki ?V eFp  
!|J2o8g  
public void setSFileName(String value) J!QIMA4{  
{ vcP_gJz  
sFileName = value; 7VLn$q]:  
} |k: FNu]C  
Jg.^h1>x  
[XP\WG>s  
public int getNSplitter() gU@R   
{ Iqj?wI 1)  
return nSplitter; D3+<16[,  
} +}f}!h;  
h;OHpvk  
T!1XL7  
public void setNSplitter(int nCount) 1CUI6@Cz)  
{ @G|z _  
nSplitter = nCount; 8K\S]SZ  
} \`*]}48Z  
} h~=~csya:  
:p$Q3  
y XCZs  
/* L*{E-m/  
**Utility.java Yg;7TKy  
*/ ;;432^jD  
package NetFox; LS<*5 HWX  
,jy9\n*<t9  
$A98h -*x  
public class Utility { k+eeVy  
1<0Z@D~F  
B2)5Z]  
public Utility() <II>io ;  
{ fV!~SX6S  
H00iy$R  
QghL=  
} H 9?txNea  
Jg6@)<n  
//线程睡眠 ;"NW= P&  
public static void sleep(int nSecond) * YLp C^&  
{ d(,M  
try{ Z3dI B`@  
Thread.sleep(nSecond); c$;Cpt@-j  
} byk9"QeY\  
catch(Exception e) {@t6[g++  
{ '*K%\]  
e.printStackTrace (); CI|#,^  
} @3?dI@i(  
} =vb'T  
y*-D  
//日志 )jw!, "_4  
public static void log(String sMsg) ?oU5H  
{ b C"rQJg  
System.err.println(sMsg); k !g%vx  
} ca'c5*Fs  
o"qG'\x  
aBKJd  
public static void log(int sMsg) [-nPHmZV[  
{ G;J!3A;TE  
System.err.println(sMsg); TTSq}sb}  
} Ge*N%=MX 8  
} 4B-+DH>{6  
Fw%S%*B8g  
e#ne5   
/* 1 @q"rPE^  
**TestMethod.java fs, >X!l+  
*/ zy8D&7Ytf  
package NetFox; EV R>R  
|#22pq?RP  
b Kr73S9  
public class TestMethod { 0E^S!A 7  
~mT([V  
X D \;|  
public TestMethod() q)RTy|NJ^  
{ ///xx/weblogic60b2_win.exe %)y-BdSp.  
try{ fLuOxYQbf  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Htce<H-P  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); #D%l;Ae  
SiteFileFetch fileFetch = new SiteFileFetch(bean); is{H >#+"  
fileFetch.start(); YF)c.Q0  
} oox;8d4}y  
catch(Exception e){e.printStackTrace ();} TcH7!fUj  
YS>VQl  
&[[Hfs2:-]  
} r@G34Q C+  
2nI^fVR%\  
uh3<%9#\k  
public static void main(String[] args) H  `_{n<  
{ 5Qxm\?0J  
new TestMethod(); VW**N}1#C  
} @.h;k4TD  
} PLK;y  
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