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http断点续传简单实现(java)

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/* rZ5xQ#IA  
**SiteFileFetch.java Rq e|7/As  
*/ W1Fhx`  
package NetFox; y`5 ?  
import java.io.*; JUj.:n2e  
import java.net.*; (CH6Q]Wi_!  
yiXb<g+B  
[\ Sd*-  
public class SiteFileFetch extends Thread { e-UWbn'~  
6[RTL2&W  
1JdMw$H  
SiteInfoBean siteInfoBean = null; //文件信息Bean ~Ym*QSD  
long[] nStartPos; //开始位置 ]bmf}&  
long[] nEndPos; //结束位置 f%1\1_^g  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7fzH(H  
long nFileLength; //文件长度 M #0v# {o  
boolean bFirst = true; //是否第一次取文件 K^[m--  
boolean bStop = false; //停止标志 ~;pP@DA  
File tmpFile; //文件下载的临时信息 py':36'  
DataOutputStream output; //输出到文件的输出流 6vxRam6[??  
WlY\R>x#  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) n9 FA` e  
public SiteFileFetch(SiteInfoBean bean) throws IOException 7\$b%A  
{ cyP+a  
siteInfoBean = bean; xh CQ Rw  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); uPN^o.,/.  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); I![/bwObG  
if(tmpFile.exists ()) m@*aA}69  
{ e]ST0J"  
bFirst = false; TOgH~R=  
read_nPos(); 8tf>G(I{  
} ]]`[tVaFr  
else Z,\(bW qF  
{ N%q{CYF6  
nStartPos = new long[bean.getNSplitter()]; #lSGH 5Fp?  
nEndPos = new long[bean.getNSplitter()]; sh0x<_  
} Q%!xw(  
7<(U`9W/q  
hH-!3S2'  
59:kL<;S-  
} "R-j  
dD'KP4Io@  
n ~&ssFC  
public void run() wv\"(e7(  
{ r4gLoHD)  
//获得文件长度 'Z,7{U1P  
//分割文件 *%_M?^  
//实例FileSplitterFetch Xkx&'/QG,U  
//启动FileSplitterFetch线程 pNuU{:9 B0  
//等待子线程返回 nehk8+eV_  
try{ 2$b1q!g<  
if(bFirst) vO"E4s  
{ 0R+p\Nc&1  
nFileLength = getFileSize(); wt'"<UN  
if(nFileLength == -1) %iYro8g!,  
{ +!`$(  
System.err.println("File Length is not known!"); LV0gw"  
} ;Z;` BGZJ  
else if(nFileLength == -2) cFJZ|Ld  
{ rW~G'  
System.err.println("File is not access!"); ,If"4C!w  
} B VH)!]m0  
else qX6zk0I a  
{ VC Ay~,  
for(int i=0;i<nStartPos.length;i++) x 0vW9*&  
{ i!JSEQ_8  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); '&gUAt  
} j\Fbi3H  
for(int i=0;i<nEndPos.length-1;i++) ZD$I-33W  
{ B tJF1#f  
nEndPos = nStartPos[i+1]; l +`CgYo  
} ; +Ie<oW  
nEndPos[nEndPos.length-1] = nFileLength; @8:c3 (!  
} =KnHa.%  
}  s-&i!d  
(tzAUrC  
4 BNbS|?vV  
//启动子线程 &#~U1: 0  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; u`-:'@4  
for(int i=0;i<nStartPos.length;i++) %)^0NQv  
{ 1. Q"<[M  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), bZQ_j#{$  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), i !SN"SY  
nStartPos,nEndPos,i); *>o@EUArN  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); u+jx3aP:  
fileSplitterFetch.start(); ~+RrL,t#  
} xBw ua;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), t)(>E'X x  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 8jLO-^X<<  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", s>>lf&7  
nEndPos = " + nFileLength); ,d=Dicaz  
// fileSplitterFetch[nPos.length-1].start(); b+CvA(*  
gKPqU@$*  
Zyz)`>cB  
//等待子线程结束 k9\n='OI  
//int count = 0;  f|yq~3x)  
//是否结束while循环 3zM>2)T-  
boolean breakWhile = false; /wHfc[b>  
ZQ_~ L!ot  
dGR #l)  
while(!bStop) IY(;:#l  
{ (51;cj>J  
write_nPos(); IUh)g1u41O  
Utility.sleep(500); n.P $E  
breakWhile = true; Ye  >+  
)$2h:dw_  
g%4=T~  
for(int i=0;i<nStartPos.length;i++) . ve a[  
{ -#AO4xpI  
if(!fileSplitterFetch.bDownOver) 3[m~6 Ys  
{ 4'`*Sce}  
breakWhile = false; |qq29dS?  
break; {UhpN"'"n  
} 4&`d$K  
} {?IUf~<  
if(breakWhile) bGB5]%v,  
break; zn\$6'"  
).$kp2IN  
2QIo|$  
//count++; VZA>ErB  
//if(count>4) FvBnmYn W  
// siteStop(); %-NG eN8  
} <bBgevL+_K  
GIUyW  
L7.LFWq$S  
System.err.println("文件下载结束!"); ]jP 0Z#  
} v #Q(g/^  
catch(Exception e){e.printStackTrace ();} B :1r;8{j  
} \&Oc}]  
]#$r TWMl'  
0Jm)2@  
//获得文件长度 "LVN:|!  
public long getFileSize() +n<;);h  
{ 45Q#6Bt E  
int nFileLength = -1; 0:>C v<N  
try{ Yp9%u9tNq  
URL url = new URL(siteInfoBean.getSSiteURL()); _qS4Ns/4s  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .OF2O}  
httpConnection.setRequestProperty("User-Agent","NetFox"); uF-Rl## >  
UTuOean ]'  
62/tg*)  
int responseCode=httpConnection.getResponseCode(); )7N$lY<  
if(responseCode>=400) B]cV|S|  
{ 5U JMiwP{  
processErrorCode(responseCode); <d3N2  
return -2; //-2 represent access is error (_~Dyvo  
} "eKM<S  
BH?fFe&J:`  
K%>3ev=y.s  
String sHeader; 1f5;^T I  
*3!ixDX[r  
4= hz4(5a  
for(int i=1;;i++) YR68'Sft[  
{ GG`;c?d@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =xHzhh  
//Utility.log(in.readLine()); 7C^W<SUo  
sHeader=httpConnection.getHeaderFieldKey(i); '\B!1B>T  
if(sHeader!=null) +}!FP3KgT  
{ AaJnRtBS~  
if(sHeader.equals("Content-Length")) xy<)zKp  
{ \F),SL  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); _ ~E_#cNn  
break; _VAX~Y]  
} ltG|#(  
} k|_LF[*Z  
else ^9*Jz{e  
break; SV_b(wP9  
} )'t&LWS~  
} NiH.Pv)Oa'  
catch(IOException e){e.printStackTrace ();} 7.1FRxS  
catch(Exception e){e.printStackTrace ();} )m$i``*<  
C]%}L%,  
o_%gFV[q  
Utility.log(nFileLength); 'tzN.p1O  
Q!}LtR$  
G!m;J8#m(  
return nFileLength; `v1~nNoY  
} ndB*^nT  
>U'gQS?\]  
JAcNjzL  
//保存下载信息(文件指针位置) g 2&P  
private void write_nPos() U10:@Wzh  
{ H=7Nh6v  
try{ RB/;qdqR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 2o9IP>#u  
output.writeInt(nStartPos.length); D,;6$Pvg^  
for(int i=0;i<nStartPos.length;i++) G_n~1?  
{ }h`ddo  
// output.writeLong(nPos); bjGQ04da  
output.writeLong(fileSplitterFetch.nStartPos); 1 gx(L*y,  
output.writeLong(fileSplitterFetch.nEndPos); {'eF;!!Dy  
} 7W\aX*]  
output.close(); m^ [VM&%  
} S?LUSb  
catch(IOException e){e.printStackTrace ();} iQ_^MzA  
catch(Exception e){e.printStackTrace ();} Fo[=Dh*AqU  
} !3Me 6&$O  
8qQrJFm|3*  
+%RB&:K7,  
//读取保存的下载信息(文件指针位置) q|7$@H^*  
private void read_nPos() ]k.'~ Syz  
{ QDJ:LJz\  
try{ w `r)B`!g  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1:d,8  
int nCount = input.readInt(); :s'hXo  
nStartPos = new long[nCount]; H;rLU9b  
nEndPos = new long[nCount]; 5X"WgR;  
for(int i=0;i<nStartPos.length;i++) 23WlUM  
{ kv'gs+,e  
nStartPos = input.readLong(); (J/!9NS:  
nEndPos = input.readLong(); R?GF,s<j  
} #^&.*' z%z  
input.close(); YO^iEI.  
} @jevY81)  
catch(IOException e){e.printStackTrace ();} GjvTYg~  
catch(Exception e){e.printStackTrace ();} Sk&l8"  
} ZRo-=/1  
2k3yf_N  
meNz0ve  
private void processErrorCode(int nErrorCode) `d i/nv)  
{ BY^5z<^.  
System.err.println("Error Code : " + nErrorCode); O/2Jz  
} i7(\i2_P  
vAp?Zl?g  
-$m?ShDd  
//停止文件下载 ^L;k  
public void siteStop() Q.Ljz Z  
{ i@ XFnt  
bStop = true; 5!)_" u3  
for(int i=0;i<nStartPos.length;i++) oc3}L^aD  
fileSplitterFetch.splitterStop(); (N25.}8Y  
'=eE6=m^K  
<FFaaGiE>  
} @:"GgkyDl#  
} koAM",5D  
//负责部分文件的抓取 jIs2R3B  
**FileSplitterFetch.java y?s8UEC  
*/ mjz<,s`D  
package NetFox; '+{dr\nJ  
l]o)KM<  
6 C|]Fm  
import java.io.*; SQd`xbIuL  
import java.net.*; iNAaTU  
HfgK0wIi  
Bpw<{U  
public class FileSplitterFetch extends Thread { Rr>h8Ni <  
hPHrq{YZ  
Du2v,n5@  
String sURL; //File URL !HP/`R  
long nStartPos; //File Snippet Start Position vAMr&[  
long nEndPos; //File Snippet End Position j L[ hB  
int nThreadID; //Thread's ID J6Q}a7I#  
boolean bDownOver = false; //Downing is over DfQD!}=  
boolean bStop = false; //Stop identical az2CFd^M  
FileAccessI fileAccessI = null; //File Access interface 8fwM)DKS  
.xp|w^  
Ew kZzVuX  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException t846:Z%[  
{ a:3f>0_t  
this.sURL = sURL; ;c_pa0L  
this.nStartPos = nStart; w+0Ch1$  
this.nEndPos = nEnd; )4P5i b  
nThreadID = id; zsx12b^w  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 f{DcR"  
} \!tS|h  
Lx"a#rZ  
4{r_EV[(  
public void run() %g>{m2o  
{ PNbs7f  
while(nStartPos < nEndPos && !bStop) f1RfNiW.  
{ !B3lsXLSY  
dIR6dI   
q|A-h'  
try{ 3[jk}2R';p  
URL url = new URL(sURL); D@ji1$K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i Y2%_b!5  
httpConnection.setRequestProperty("User-Agent","NetFox"); Mwdw7MZ"S  
String sProperty = "bytes="+nStartPos+"-"; nd] AvVS  
httpConnection.setRequestProperty("RANGE",sProperty); XTZI !  
Utility.log(sProperty); V!S B9t`E  
(1vmtg.O  
-0) So  
InputStream input = httpConnection.getInputStream(); LEJ7.82  
//logResponseHead(httpConnection); DvuL1Me Ko  
IrRn@15,  
adJoT-8P6  
byte[] b = new byte[1024]; 2rw<]Ce  
int nRead; Wsr #YNhx|  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "Jp6EL%  
{ 2Z-BZuK6p  
nStartPos += fileAccessI.write(b,0,nRead); 3o'SY@'W  
//if(nThreadID == 1) rGZ@pO2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IP1|$b}sq  
} C3%,pDh  
Te{L@sj  
^j2:fJOU#  
Utility.log("Thread " + nThreadID + " is over!"); +M\*C#  
bDownOver = true; .~5cNu'#m  
//nPos = fileAccessI.write (b,0,nRead); tc{23Rf%  
} b'N"?W^YQ  
catch(Exception e){e.printStackTrace ();} aNW&ib  
} P-~Avb  
} *TuoC5  
azB~>#H~  
n^/,>7J   
//打印回应的头信息 b)u9#%Q  
public void logResponseHead(HttpURLConnection con) d]e`t"Aj  
{  <C4^Vem  
for(int i=1;;i++) l!ye\  
{ is}Fy>9i  
String header=con.getHeaderFieldKey(i); v] *W*;  
if(header!=null) XEZ6%Q_  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); tS2lex%  
Utility.log(header+" : "+con.getHeaderField(header)); 8IC((  
else _<.R\rX&  
break; e_6 i896  
} f|VP_o<  
} ,ASY &J5)7  
j.C C.[$g  
YA^9, q6u?  
public void splitterStop() N13 <!QQ  
{ CWkm\=  
bStop = true; No[xf9>t  
} &F#X0h/m=  
bi^LpyEn  
A|>a Gy  
} wCvD4C.WH  
kX1hcAa  
5<w0*~Z d~  
/* 33Mr9Doon  
**FileAccess.java 4 qW)R{%  
*//文件访问(定位,写) n?,fF(  
package NetFox; 9Zrn(D  
import java.io.*; .^kTb2$X  
_k+Bj.L  
*pasI.2s#  
public class FileAccessI implements Serializable{ 6-X7C9`C  
N&>D/Z;"  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 QW2% Gv:  
RandomAccessFile oSavedFile; \iVYhl  
long nPos; kLD)<D  
R4qk/@]t  
2N,*S   
public FileAccessI() throws IOException Ar'5kPzY>  
{ d&'6l"${  
this("",0); ]c5GG!E-g  
} xU rfH$$!`  
4t8 Hy  
Vfw$>og!  
public FileAccessI(String sName,long nPos) throws IOException f:utw T  
{ E_yh9lk  
oSavedFile = new RandomAccessFile(sName,"rw"); &FanD   
this.nPos = nPos; ?y04g u6p  
oSavedFile.seek(nPos); :!A@B.E  
} $K G?d>wx  
OQsH,'  
oL6_Ya  
public synchronized int write(byte[] b,int nStart,int nLen) 3> fuH'=  
{ ja>Tnfu  
int n = -1; [D?E\Nkk  
try{ er<~dqZ}]  
oSavedFile.write(b,nStart,nLen); (Pu*[STTT  
n = nLen; G/`_$ c  
} tIvtiN6[|l  
catch(IOException e) da<1,hF  
{ (^Ln|3iz  
e.printStackTrace (); l;;:3:  
} W.CIyGK  
>3Y&jsh<  
Je*gMq:D  
return n; *LhR$(F(  
} )i>KYg w  
4i19HD_  
5y~[2jB:  
} UmJg-~  
C'$U1%: j  
N!va12  
/* G dooy~cn  
**SiteInfoBean.java AUq?<Vg\  
*/ /;>EyWW  
package NetFox;  6$Dbeb  
#QB`'2)vw  
2KX *x_-   
public class SiteInfoBean { }$UFc1He\J  
I'j? T.  
/za,&7sf  
private String sSiteURL; //Site's URL oc?VAF  
private String sFilePath; //Saved File's Path u/zfx ;K  
private String sFileName; //Saved File's Name ~& l`"  
private int nSplitter; //Count of Splited Downloading File 3A9|{Vaz+6  
qjFgy)qV  
aD:+,MZ  
public SiteInfoBean() bd9c/>&  
{//nSplitter的缺省值为5 s0h)~z  
//default value of nSplitter is 5 0'<S7?~|  
this("","","",5); qnlj~]NV  
} $ S49v  
8BN'fWl&E  
-_}EQ9Q  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ?\yo~=N^  
{ xWMMHIu  
sSiteURL= sURL; +1y#=iM{  
sFilePath = sPath; v 7R&9kU{  
sFileName = sName; F,bl>;{[{  
this.nSplitter = nSpiltter; %|I|Mc  
Mc6y'w  
 96BMJE'  
} G1l(  
GB=q}@&8p  
e'`oisJU?q  
public String getSSiteURL() N 4:'X6u;  
{ gM*s/,;O"  
return sSiteURL; x0d+cSw  
} TQou.'+v  
:U 9R 1^}A  
yV8).4  
public void setSSiteURL(String value) _pS%tPw  
{ t'J fiGM  
sSiteURL = value; bm4W,  
} gU?)  
0D'Wr(U(  
>W;i2%T  
public String getSFilePath() H@zk8]_P  
{ b>i=",i\  
return sFilePath; w#e'K-=  
} AUC< m.  
>$y >  
d}ZH Y[  
public void setSFilePath(String value) {ZcZ\Q;6  
{ -db+Y:xUZ  
sFilePath = value; z)%1i  
} C gx?K]>y  
-  -G1H  
fo.m&mKgo  
public String getSFileName() E ( @;p%:  
{ :3B\,inJ  
return sFileName; $c}0L0  
} my1kF%?  
a%dx\&K  
_#C}hwOR>X  
public void setSFileName(String value) Xo`1#6xsE  
{ IfcFlXmt2  
sFileName = value; ,<1*  
} ! Cl/=0$[L  
+2SX4Kxu  
h uJqqC  
public int getNSplitter() #lF<="y%X  
{ f[I c hCwX  
return nSplitter; i.sq^]j  
} guv@t&;t0  
ZhsZy wM  
"b 0cj  
public void setNSplitter(int nCount) %U GlAyj  
{ >v[(w1?rX  
nSplitter = nCount; ^mi4q[PM  
} N-gRfra+8L  
} !qlGt)G3  
blcKtrYg  
vgj^-  
/* D.(G9H  
**Utility.java Rs`a@ Fn  
*/ &>e DCs  
package NetFox; YJ$ewK4E#.  
B5:g{,C  
F-^HN%  
public class Utility { yf)`jPM1<  
(fa?f tK  
 2JP?6N  
public Utility() KeB4Pae|V  
{ 4MJzx9#  
)\-";?sYky  
(L$~ zw5gr  
} "ILWIzf.]  
@@IA35'tc  
//线程睡眠 "!tw ,Gp  
public static void sleep(int nSecond) 6[.Mx}h6  
{ Hc]1mM  
try{ N;'HR)  
Thread.sleep(nSecond); <(4#4=ivP  
} ,SF.@^o@a  
catch(Exception e) 8[)]3K x  
{ 6#M0AG  
e.printStackTrace (); |QLX..  
} aMQjoamz  
} A Vm{#^p[(  
~lqGnNhh 7  
//日志 U@MP&sdL  
public static void log(String sMsg) |xZcT4  
{ <z uE=0P~%  
System.err.println(sMsg); R9h>I3F=c  
} {~fCqP.2  
4q13xX  
c1kxKxE  
public static void log(int sMsg) W@,p9=425  
{ KC:4  
System.err.println(sMsg);  YX`=M  
} 9K':Fn2,  
} kLt9; <L  
-'[(Uzj  
:z.Y$]F@  
/* drKjLo[y  
**TestMethod.java M J,ZXJXs  
*/ xs!g{~V{  
package NetFox; ^}Qj}  
4iNbK~5j  
s;2/Nc   
public class TestMethod { 3;MjO*-  
sD8 m<   
NOr <,  
public TestMethod() Z.':&7Y  
{ ///xx/weblogic60b2_win.exe ncattp   
try{ /%YiZ#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); E0 eQ9BXh  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); LkGf|yd_  
SiteFileFetch fileFetch = new SiteFileFetch(bean); pp]_/46nN  
fileFetch.start(); nS+FX& _  
} 4r[pMJiq  
catch(Exception e){e.printStackTrace ();} o}MzqKfu  
Sf&?3a+f  
jD/7/G*  
} XDkS ^9  
M6]0Y@@>  
6 W;?8Z_1  
public static void main(String[] args) *)bd1B#  
{ ?#m<\]S<  
new TestMethod(); AL]h|)6QpC  
} pSQCT  
} zD2.Q%`IM  
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