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http断点续传简单实现(java)

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/* 9(F?|bfk  
**SiteFileFetch.java 'TrrOq4  
*/ OZ;E&IL  
package NetFox; 'h^DI`  
import java.io.*; ,:(leWeA9  
import java.net.*; <M OL{jan  
b<(UmRxx3  
4<g72| y  
public class SiteFileFetch extends Thread { ;]M67ma7C  
-fx88  
\ui^ d  
SiteInfoBean siteInfoBean = null; //文件信息Bean m90R8  V  
long[] nStartPos; //开始位置 i>Bi&azx  
long[] nEndPos; //结束位置 c;rp@_ULG?  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 z83:a)U  
long nFileLength; //文件长度 `O=;E`ep  
boolean bFirst = true; //是否第一次取文件 9T,QW k  
boolean bStop = false; //停止标志 pd>a6 lI`  
File tmpFile; //文件下载的临时信息 :5K ~/=6x  
DataOutputStream output; //输出到文件的输出流 K}=8:BaUL  
a^T4\  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) R, w54},  
public SiteFileFetch(SiteInfoBean bean) throws IOException <oaBh)=7  
{ 9;Pu9s[q2  
siteInfoBean = bean; g} ~<!VpX  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ?3TK7]1V:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); b)hOzx  
if(tmpFile.exists ()) khN:+V|  
{ K aQq[a  
bFirst = false; ~:}XVt0%8  
read_nPos(); /-K dCp~  
} R`C_CsXir  
else %M)oHX1p  
{ 7YXXkdgbd  
nStartPos = new long[bean.getNSplitter()]; ({_:^$E\  
nEndPos = new long[bean.getNSplitter()]; B mBzOk^  
} )47j8jL  
H=o-ScA  
C|d!'"p  
X\^& nLa  
} p-yOiG8b}  
P$6f+{  
R3{*v =ov  
public void run() (LT\ IJSM  
{ /,!7jF:  
//获得文件长度 Xk&F4BJQk<  
//分割文件 Fy _<Ui  
//实例FileSplitterFetch ok>P [ &!  
//启动FileSplitterFetch线程 ;+ C o!L  
//等待子线程返回 Q 9gFTLQ  
try{ K* _{Rs0P  
if(bFirst) =wlm  
{ tgvpf /cQ  
nFileLength = getFileSize(); 93^(O8.  
if(nFileLength == -1) .i3lG( YG  
{ @!&Jgg53G  
System.err.println("File Length is not known!"); 6& &}P79  
} 94h_t@Q/1  
else if(nFileLength == -2) *m| t =9E  
{ ezg^5o;  
System.err.println("File is not access!"); |?2 hml  
} TJyH/ C  
else BS-:dyBw  
{ BDm88< ]  
for(int i=0;i<nStartPos.length;i++) '!+ P{  
{ ;* wT,2;  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \f /!  
} o%/-5-  
for(int i=0;i<nEndPos.length-1;i++) ?`N57'iPb  
{ #Cg}!38  
nEndPos = nStartPos[i+1]; '&.)T 2Kw  
} Mz/]DJ8  
nEndPos[nEndPos.length-1] = nFileLength; v9t4 7>V  
} -'O Q-5  
} f!M[awj%  
TbKP8zw{  
5#TrCPi6A  
//启动子线程 xfV,==uF  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; H9Y2n 0  
for(int i=0;i<nStartPos.length;i++) QD.zU/F~>  
{ IdV,%d{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (C-,ljY  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [):{5hMA  
nStartPos,nEndPos,i); ;NiArcAS!  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); } * ?n?'  
fileSplitterFetch.start(); D EUd[  
} u%6Irdx  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), %XEKhy  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); E3 ~,+68U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 5+e>+$2  
nEndPos = " + nFileLength); %sOWg.0_  
// fileSplitterFetch[nPos.length-1].start(); #dva0%-1  
LJRg>8  
g9yaNelDh)  
//等待子线程结束 &\;<t, 3A~  
//int count = 0; Hv8SYQ|  
//是否结束while循环 Od0S2hHO  
boolean breakWhile = false; xoqiRtlY:  
*'UhlFed  
d&}pgb-Md  
while(!bStop) +R|U4`12  
{ &Q\_;  
write_nPos(); 5SoZ$,a<e  
Utility.sleep(500); E S#rs="  
breakWhile = true; Yw6DJY  
k_,MoDz  
A)\>#Dv  
for(int i=0;i<nStartPos.length;i++) V~/.Y&WN  
{ 'M~BE\  
if(!fileSplitterFetch.bDownOver) 7%{R#$F  
{ 6BDt.bG  
breakWhile = false; i LF^%!:X%  
break; xj0cgK|!  
} /SnynZ.q  
} \n[ 392  
if(breakWhile) 6exRS]BI  
break; <A)+|Y"^h6  
%4j&H!y-w;  
?QGmoQ)  
//count++; z )5S^{(  
//if(count>4) Q m $(  
// siteStop(); o[o:A|n  
} M(qxq(#{U  
. 3Gn ZR,L  
kt :)W])V  
System.err.println("文件下载结束!"); } <SNO)h3  
} \;-qdV_JB  
catch(Exception e){e.printStackTrace ();} ?$3r5sx  
} Am=wEu[b  
K>kLUcC7Z  
lY.B  
//获得文件长度 J2r1=5HS  
public long getFileSize() +)gGs# 2X  
{ (B&h;U$HAH  
int nFileLength = -1; z/S,+!|z  
try{ 2 #KoN8%  
URL url = new URL(siteInfoBean.getSSiteURL()); .Y!:x =e  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B#]_8svO  
httpConnection.setRequestProperty("User-Agent","NetFox"); =HMmrmz:  
,*dzJT$k  
Kh)F yV  
int responseCode=httpConnection.getResponseCode(); `|]e6Pb  
if(responseCode>=400) Uh.Sc:trA  
{ en>9E.?N  
processErrorCode(responseCode); e&2wdH&  
return -2; //-2 represent access is error _F izgs  
} CN/IH   
=O,JAR"ug  
W}h|K:-S  
String sHeader; !h>D;k6 e  
a\pi(9R  
('t kZt%8  
for(int i=1;;i++) S8%n.<OB  
{ %,|ztH/ Q  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  5@ foxI  
//Utility.log(in.readLine()); &3Tx@XhO  
sHeader=httpConnection.getHeaderFieldKey(i); J3G7zu8  
if(sHeader!=null) kJkxx*:u  
{ Fd7*]a  
if(sHeader.equals("Content-Length")) (;}tf~~r  
{ , H2YpZk  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Pd~MiyO;K  
break; ID4~ Gn  
} -4flV D  
} 6e.v&f7(  
else ,)h)5o(?  
break; Fc8E Y*  
} %9o+zg? RJ  
} MdC<4^|  
catch(IOException e){e.printStackTrace ();} i"HgvBHx  
catch(Exception e){e.printStackTrace ();} ~O: U|&  
5j eO"jB  
2yKz-"E  
Utility.log(nFileLength); F>+2DlA`<e  
NP/>H9Q2%  
5+P@s D  
return nFileLength; \DA$6w\\  
} !gH 9ay  
8~ #M{}  
Z0ReWrl;`  
//保存下载信息(文件指针位置) n#*`!#  
private void write_nPos() u1cu]Sj0  
{ #SkX@sl@  
try{ ( 9$"#o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); *Oo &}oAj  
output.writeInt(nStartPos.length); Y ?'tUV  
for(int i=0;i<nStartPos.length;i++) :gI.l1  
{ b2 kWjg.4  
// output.writeLong(nPos); 5HlWfD  
output.writeLong(fileSplitterFetch.nStartPos); u+D[_yd^  
output.writeLong(fileSplitterFetch.nEndPos); s_eOcm  
} ZPO|<uR  
output.close(); 1H{jy^sP7  
} otr>3a*'  
catch(IOException e){e.printStackTrace ();} 7Kf}O6nE  
catch(Exception e){e.printStackTrace ();} V U~Dk);Bv  
} 61_f3S(u  
Veji^-0E  
w([$@1]  
//读取保存的下载信息(文件指针位置) [@"wd_f{l  
private void read_nPos() z.)p P'CJo  
{ -<N&0F4|*  
try{ I*\^,ow  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); #c Kqnk  
int nCount = input.readInt(); PRs@zkO  
nStartPos = new long[nCount]; Ec]|p6a3  
nEndPos = new long[nCount]; I@ \#up}  
for(int i=0;i<nStartPos.length;i++) o-eKAkh  
{ #^rU x.  
nStartPos = input.readLong(); 1 W'F3  
nEndPos = input.readLong(); SEF6B45}1  
} YQ(Po!NI\'  
input.close(); $.K?N@(W  
} GsV4ZZ  
catch(IOException e){e.printStackTrace ();} ZR3nK0  
catch(Exception e){e.printStackTrace ();} P $ >`  
} HJhH-\{@  
c-CYdi@  
sR_xe}-  
private void processErrorCode(int nErrorCode) I mym+  
{ I cF@F>>  
System.err.println("Error Code : " + nErrorCode); ;Zut@z4\  
} OXhAha`R  
>+9JD%]x]  
N$alUx*  
//停止文件下载 py<_HyJ  
public void siteStop() 'ks{D(`  
{ &__DJ''+  
bStop = true; P-Su5F  
for(int i=0;i<nStartPos.length;i++) Z(Q2Ue;}&  
fileSplitterFetch.splitterStop(); ,Og4 ?fS  
M##';x0  
*\XH+/]+  
} z&+ zl6  
} YD[H  
//负责部分文件的抓取 e~\QE0Oe:  
**FileSplitterFetch.java yTAvF\s$(  
*/ d'HOpJE  
package NetFox; RA/EpD:H  
wNQqfq Z  
zFhgE*5  
import java.io.*; 6rDfQ`f\p  
import java.net.*; iI?{"}BZ  
 [aW =  
:jem~6i  
public class FileSplitterFetch extends Thread { `y!/F?o+!  
m *X7T  
kU*{4G|6  
String sURL; //File URL UQ8bN I7  
long nStartPos; //File Snippet Start Position 'fW#7W  
long nEndPos; //File Snippet End Position /oP^'""@je  
int nThreadID; //Thread's ID Tj/GClD:%  
boolean bDownOver = false; //Downing is over 4\2V9F{s  
boolean bStop = false; //Stop identical ^^?q$1k6r*  
FileAccessI fileAccessI = null; //File Access interface `rFAZcEj%  
2V gP  
\C|cp|A*&  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 1(gfdx9|b  
{ v%91k  
this.sURL = sURL; jj&s} _75  
this.nStartPos = nStart; 9K"JYJ q2  
this.nEndPos = nEnd; ;u-4KK  
nThreadID = id; i^2IW&+}e}  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 8<&EvOk  
} i@$*Csj\9*  
sa#.l% #  
5M){!8"S)#  
public void run() O!F]^'!  
{ k onoI&kV|  
while(nStartPos < nEndPos && !bStop) f`P9ku#j}  
{ oyeG$mpg  
CEtR[Cu  
hC<14  
try{ nWgv~{,x  
URL url = new URL(sURL); t1i(;|8|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ')TPF{\#  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3LK%1+)4  
String sProperty = "bytes="+nStartPos+"-"; +=fKT,-*G!  
httpConnection.setRequestProperty("RANGE",sProperty); e3(<8]`b[  
Utility.log(sProperty); %}qbkkZ  
{NQo S"  
v Xcy#  
InputStream input = httpConnection.getInputStream(); fE25(wCz7  
//logResponseHead(httpConnection); ?[= U%sPu=  
*xH\)|3,  
SkP[|g'56  
byte[] b = new byte[1024]; bBE+jqi 2  
int nRead; F!g;A"?V  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5P ke8K  
{ Spj9H?m  
nStartPos += fileAccessI.write(b,0,nRead); WZ~> BM  
//if(nThreadID == 1)  ]PX}b  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); \{v,6JC  
} [)|+F wJ  
ElR)Gd_8  
KD*O%@X5C  
Utility.log("Thread " + nThreadID + " is over!"); ~j& ?/{7I  
bDownOver = true; 2Rptxb_@  
//nPos = fileAccessI.write (b,0,nRead); 6 =>G#  
} J r*"V`  
catch(Exception e){e.printStackTrace ();} <GZhH:  
} ,"G\f1  
} ,2zKQ2z  
{bkGYx5.C  
Fd8hGj1  
//打印回应的头信息 Yj8&  
public void logResponseHead(HttpURLConnection con) u0]q`u/ T  
{ F`& >NQb  
for(int i=1;;i++) w}k B6o]  
{ fusPMf *[  
String header=con.getHeaderFieldKey(i); r{ @ `o@q  
if(header!=null) O@,i1ha%  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); &?T${*~  
Utility.log(header+" : "+con.getHeaderField(header)); x0G>ktWq<  
else z,+m[x=/N  
break; |- OHve4A  
} 4#2 ,Y!  
} 5 ,ZRP'oI  
Oz>io\P94  
Q8Te'1Ln!  
public void splitterStop() :,YLx9i>  
{ 'j#a%j@{  
bStop = true;  -$R5  
} ^[TOZXL`:  
z7q%,yw3N  
<^sAY P|  
} VjTAN=  
sT1j F3  
k2uBaj]  
/* \e0x ,2  
**FileAccess.java *a4 b  
*//文件访问(定位,写) qKs7WBRJy  
package NetFox; :BDviUC7Z  
import java.io.*; OfLM  
rgn|24x  
? ,V;f2c  
public class FileAccessI implements Serializable{ 05g?jV  
c#x7N9;"!  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 [Ekgft&  
RandomAccessFile oSavedFile; ULrbQ}"cva  
long nPos; F]SIT\kBm  
w6v1 q:20  
hhj ,rcsi  
public FileAccessI() throws IOException J\GKqt;5@  
{ Nc:U4  
this("",0); BGYm]b\j[  
} V<I${i$]0  
~G^doj3|+  
X#C7r@H  
public FileAccessI(String sName,long nPos) throws IOException P VW9iT+c  
{ aV%rq9Tp  
oSavedFile = new RandomAccessFile(sName,"rw"); /XK`v=~(l{  
this.nPos = nPos; 49kia!FR  
oSavedFile.seek(nPos); *X55:yha  
} xb_:9   
E|#R0n*  
Wb(0Szk;  
public synchronized int write(byte[] b,int nStart,int nLen) <"P '"SC  
{ c|a|z}(/J  
int n = -1; Hjkgy%N  
try{ 0cU^ue%  
oSavedFile.write(b,nStart,nLen); $ T_EsnN  
n = nLen; (:muxby%  
} 31;T$5v1  
catch(IOException e) ;;H:$lx  
{ DfFPGFv  
e.printStackTrace (); ?pY!sG  
} {j@)sDM X  
1g.9R@Kc$  
LX&P]{q KS  
return n; JNl+UH:.  
} uQ1;+P:L  
mwhn=y#]*  
J8Db AB4X  
} Qeog$g.HI  
x)5v8kgf  
=^M t#h."  
/* }w8AnaC  
**SiteInfoBean.java <}1%">RA  
*/ 9Q1GV>j>B  
package NetFox; M.Ik%nN#K0  
+yI^<BH  
F'*&-l  
public class SiteInfoBean { =*U24B*U93  
cyE2=  
%%[TM(z  
private String sSiteURL; //Site's URL h;M2yl Ou.  
private String sFilePath; //Saved File's Path K~>kruO";  
private String sFileName; //Saved File's Name AtOB'=ph*  
private int nSplitter; //Count of Splited Downloading File Dr:}k*  
{cA )jW\'  
~Zm(p*\T  
public SiteInfoBean() w[ngkLEA  
{//nSplitter的缺省值为5 Yt^+31/%  
//default value of nSplitter is 5 ceCshxTU  
this("","","",5); 2srz) xEe  
} {Hv=iVmt  
4 #N#[;M  
L%"Mp(gZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) "=;&{N~8U  
{ o v~m?Y]h  
sSiteURL= sURL; N\?iU8w=  
sFilePath = sPath; ?8 F7BS4oQ  
sFileName = sName; ZU|nKt<GK  
this.nSplitter = nSpiltter; Fk4 3sqU6~  
cPXvT Vvs  
e_TM#J(3  
} @b zrJ 7$  
)+G(4eIT  
M: 6 cma5  
public String getSSiteURL() LtQy(F%8/  
{ ^cNP ?7g7  
return sSiteURL; lV?SvXe  
} }bVyvH  
L0Cf@~k  
cg~FW2Q  
public void setSSiteURL(String value) ]V_9[=%  
{ ]~P?  
sSiteURL = value; =h)H`  
} s$en5)  
BSz\9 eT  
|z~?"F6 Y<  
public String getSFilePath() yZ{YIy~  
{ ,y.0 Cb0  
return sFilePath; %lPP1 R  
} x R.Ql>  
y+PukHY  
,'j5tU?c  
public void setSFilePath(String value) ,P|PPx%@  
{ c(jA"K[|b  
sFilePath = value; !EFd- fk  
} X[w9~t$\  
s{/nO)  
Q3D xjD  
public String getSFileName() P(4[<'H O  
{ EW`3h9v~  
return sFileName; j\a?n4g -  
} EPI*~=Z.U  
&ke4":7X  
Oe273Y^e  
public void setSFileName(String value) )):22}I#  
{ <ivqe"m  
sFileName = value; &Dg)"Xji  
} pG F5aF7T  
RJ}yf|d-C  
2u*h*/  
public int getNSplitter() C6^j#rl  
{ @i1q]0  
return nSplitter; ab4LTF|  
} >r}Vf9 5[N  
4ZI_pf  
h(N=V|0  
public void setNSplitter(int nCount) M-Sv1ZLh  
{ 6+PGwCS  
nSplitter = nCount; 38Efp$)  
} hW' HT  
} ~L'nz quF  
XTo8,'UaP  
O-!,Jm   
/* ],&\%jd<  
**Utility.java ;J=:IEk  
*/ aR)?a;}H  
package NetFox; c#pj:f*H  
d+5:Qrr  
Sk=N [hwU  
public class Utility { ~ 5"J(  
X4Xf2aXI  
LdEE+"Jw  
public Utility() 6K 4+0xXv  
{ p;`N\.ld  
sFElD ]|  
4bI*jEc\[  
} QJSr:dP4dG  
* nCx[  
//线程睡眠 'vlrc[|/  
public static void sleep(int nSecond) oEIqA  
{ $?f]ZyZr.  
try{ 9v~5qv;  
Thread.sleep(nSecond); IG|\:Xz  
} x'i0KF   
catch(Exception e) wd+O5Lr.R  
{ sX'nn   
e.printStackTrace (); 2AK}D%jfc  
} Qlh?iA  
} >'Hx1;  
\EI#az=I  
//日志 o#}mkE87  
public static void log(String sMsg) r*Z_+a8  
{ g;G5 r&T  
System.err.println(sMsg); |Puj7Ru  
} fIkT"?  
hr~.Lj5^W  
<kbnu7?a*  
public static void log(int sMsg) B5`;MQJ  
{ F*\4l;NJ  
System.err.println(sMsg); Z= ik{/  
} f?-J#x)  
} ^ZVO ql&  
<<<NXsH  
e~ BJvZ}Q  
/* bd{\{[^S!  
**TestMethod.java {u4i*udG`)  
*/ EL +,jrU~  
package NetFox; b9#m m  
Z@oKz:U  
vX.]hp5~  
public class TestMethod { 8]]@S"ZM,\  
ArX]L$ D  
cNeiD@t3V&  
public TestMethod() ^'Y HJEK  
{ ///xx/weblogic60b2_win.exe }VZM,.w  
try{ D6:DrA:  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); niAZ$w  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); b"3uD`  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 07Y_^d  
fileFetch.start(); >uW^.e "F  
} z L8J`W  
catch(Exception e){e.printStackTrace ();} |?yE^$a  
g/B\ObY  
QH:>jmC{1h  
} O$U}d-Xnx  
C$_G'XI  
bq: [Nj  
public static void main(String[] args) ph+M3q(z  
{ $':JI#  
new TestMethod(); HoL~j({  
} ka8$dfC  
} ;/R kMS  
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