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http断点续传简单实现(java)

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/* E_bO9nRHV  
**SiteFileFetch.java B0ndcB-  
*/ QQV~?iW{~  
package NetFox; izx#3u$P  
import java.io.*; X 51Yfr  
import java.net.*; iT)z_  
T0]*{k(FR  
xSBc-u#< G  
public class SiteFileFetch extends Thread { eVM/uDD  
dF~8XYo  
[V) L  
SiteInfoBean siteInfoBean = null; //文件信息Bean u3o#{~E/#  
long[] nStartPos; //开始位置 EVNY*&p  
long[] nEndPos; //结束位置 L^{|uP15N  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 m,t|IgDh  
long nFileLength; //文件长度 gL3"Gg3  
boolean bFirst = true; //是否第一次取文件 5efpeu  
boolean bStop = false; //停止标志 $&2UTczp  
File tmpFile; //文件下载的临时信息 j8sH#b7Z  
DataOutputStream output; //输出到文件的输出流 wX*K]VMn  
:,DM*zBV p  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Q pmsOp|  
public SiteFileFetch(SiteInfoBean bean) throws IOException E=#0I]v[  
{ %bdjBa}  
siteInfoBean = bean; "1-}A(X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); %:2+ o'  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); _{ZqO;[u  
if(tmpFile.exists ()) %=BMZRn  
{ EKz Ad  
bFirst = false; 25&J7\P*  
read_nPos(); |eWjYGwJa  
} mSo_} je(  
else SC- $B  
{ UDL RCS8i  
nStartPos = new long[bean.getNSplitter()]; !S_^94b@  
nEndPos = new long[bean.getNSplitter()]; Q8_ d)t|  
} cDI [PJ9  
\{EpduwZ  
"hy.GWF|*  
0pSmj2/,.  
} STJJU]H  
5j-]EJb  
HdLH2+|P;D  
public void run() <2nZ&M4/s{  
{ 2 6>ZW4Z  
//获得文件长度 -<_Ww\%8M  
//分割文件 ?SC[G-b  
//实例FileSplitterFetch #-GJ&m8  
//启动FileSplitterFetch线程 XduV+$ 03  
//等待子线程返回 E(i[o?  
try{ +z$pg  
if(bFirst) O%ug@& S{  
{ a:_I  
nFileLength = getFileSize(); M5trNSL&u  
if(nFileLength == -1) A'%1ZQ33O  
{ hbc uK&  
System.err.println("File Length is not known!"); _fwb!T}$  
} 0Ld@H)  
else if(nFileLength == -2)  <Tot|R;  
{ G\a8B#hg  
System.err.println("File is not access!"); )nd\7|5#  
} @l0|*lo%  
else H&yD*@  
{ XB[<;*Iz  
for(int i=0;i<nStartPos.length;i++) 0j_bh,zG#  
{ gp-T"l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); nIvJrAm4k  
} 8L1ohj  
for(int i=0;i<nEndPos.length-1;i++) 9Mgq1Z  
{ d|iy#hy"_  
nEndPos = nStartPos[i+1]; oQL59XOT4  
} 8+Td-\IMk  
nEndPos[nEndPos.length-1] = nFileLength; 2z@\R@F  
} 1c@} C+F+  
} >g;kJe  
aIXdV2QS  
)$Z=t-q  
//启动子线程 $:of=WTY(  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8#D:H/`'  
for(int i=0;i<nStartPos.length;i++) A?*o0I  
{ ^xZ e2@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), v-! u\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), c   c  
nStartPos,nEndPos,i); HQ9X7[3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W<<9y  
fileSplitterFetch.start(); ~RD+.A  
} aSP4a+\*  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), YKa0H%B(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); kHv[H]+v  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "p3_y`h6+  
nEndPos = " + nFileLength); 9TAj) {U%'  
// fileSplitterFetch[nPos.length-1].start(); v{ <[)cr  
 P5gN#G  
[+Y{%U  
//等待子线程结束 LA[g(i 7  
//int count = 0; jp+_@S>  
//是否结束while循环 Pe2wsR"_U  
boolean breakWhile = false; dr<<!q /  
(7DXRcr<  
5ZY)nelc  
while(!bStop) -<#!DjV6(  
{ X1vNF|o~  
write_nPos(); HBB{m  
Utility.sleep(500); k'X;ruQ:tF  
breakWhile = true;  >Ng)k]G  
5%}wV,Y  
j:bgR8 %e  
for(int i=0;i<nStartPos.length;i++)  a1j.fA  
{ dC<LDxlv  
if(!fileSplitterFetch.bDownOver) gf+d!c(/  
{ y3<Y?M4  
breakWhile = false; 1h7+@#<:a  
break; ]/cd;u  
} vOgC>_x7  
} b|5w]<?'  
if(breakWhile) auWXgkwZs/  
break; rbZ[!LA  
C;~*pMAYe  
$Q+s/4\  
//count++; wLV~F[:  
//if(count>4) ~l~Tk6EM  
// siteStop(); B[9 (FRX  
} KL'zXkS  
<:|3rfm#  
tU/k-W3X  
System.err.println("文件下载结束!"); q:8_]Qt  
} voe7l+Xk  
catch(Exception e){e.printStackTrace ();} F%rHU5CkV  
} 8Q)@  
x&A vUJ  
+!0eu>~_&  
//获得文件长度 n,O5".aa<  
public long getFileSize() 6> {r6ixs1  
{ M|i o4+sy  
int nFileLength = -1; l =IeJh  
try{ y}08~L?2  
URL url = new URL(siteInfoBean.getSSiteURL()); 0D~ C 5}/4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l|V;Ys5f  
httpConnection.setRequestProperty("User-Agent","NetFox"); FP"$tt(  
N]YtLa,t  
Jg$xO@.  
int responseCode=httpConnection.getResponseCode(); _;RVe"tR#  
if(responseCode>=400) {I{:GcS  
{ ,572n[-q  
processErrorCode(responseCode); X%9*O[6{  
return -2; //-2 represent access is error XUV!C 7  
} i.1U|Pi  
uENdI2EY8y  
M*pRv  
String sHeader; e1q"AOV6  
R \s!*)  
nF)uTk  
for(int i=1;;i++) as"N=\N  
{ [*m2  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); $(q>mg:H  
//Utility.log(in.readLine()); y0ckm6^  
sHeader=httpConnection.getHeaderFieldKey(i); P|jF6?C  
if(sHeader!=null) SJgY  
{ o{-<L  
if(sHeader.equals("Content-Length")) E&~nps8e  
{ giavJ|  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 7 boJ*  
break; 3,aN8F1;C  
} y~<@x.  
} I]}>|  
else {fSf q&o  
break; 1q.(69M  
} p D=w >"  
} tu%[p 4   
catch(IOException e){e.printStackTrace ();} gY9\o#)<  
catch(Exception e){e.printStackTrace ();} +'03>!V  
J7i+c];!<  
g.Hio.fVd  
Utility.log(nFileLength); :wgfW .w  
tjv\)Nn'  
rlznwfr7+  
return nFileLength; QYThW7S  
} 2>hz_o{5',  
2RppP?M!  
(%< 'A  
//保存下载信息(文件指针位置) ]re'LC!d  
private void write_nPos() $EBb"+Y'T  
{ Jfg7\&|  
try{ So4nJ><p  
output = new DataOutputStream(new FileOutputStream(tmpFile)); s'_,:R\VM>  
output.writeInt(nStartPos.length); b7h+?!H]R  
for(int i=0;i<nStartPos.length;i++) P -Fg^tl  
{ 'dt\db5p  
// output.writeLong(nPos); 4Nmea-!*  
output.writeLong(fileSplitterFetch.nStartPos); C9KWa*3  
output.writeLong(fileSplitterFetch.nEndPos); S_8r\B[>P  
} =3ADT$YHd  
output.close(); AZZRa69=  
} PJ 9%/Nrh  
catch(IOException e){e.printStackTrace ();} E20 :uZ7\  
catch(Exception e){e.printStackTrace ();}  U w Eiz  
} %%g-GyP 1  
{K7YTLWY  
V_a)jJ  
//读取保存的下载信息(文件指针位置) ESDB[ O+`x  
private void read_nPos() %<}=xJf>1  
{ ; Zq/eiB  
try{ ?y-s20Kd  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); A 0#Y, 1  
int nCount = input.readInt(); Jyu`-=It  
nStartPos = new long[nCount]; mtw9AoO  
nEndPos = new long[nCount]; e.X@] PQJQ  
for(int i=0;i<nStartPos.length;i++) n,KA&)/s  
{ 3ps,uozj  
nStartPos = input.readLong(); C{Blqf3V0  
nEndPos = input.readLong(); 5}a"?5J^  
} \f"?Tv-C'  
input.close(); A8dI:E+$  
} 8wF#e\Va0  
catch(IOException e){e.printStackTrace ();} Gc;B[/:  
catch(Exception e){e.printStackTrace ();} 9e5gy  
} 4 iH&:Al  
v.`+I-\.z)  
.s};F/(diD  
private void processErrorCode(int nErrorCode) dERc}oAh(  
{ H~m]nV,r  
System.err.println("Error Code : " + nErrorCode); #AncOo  
} u7muaSy  
`-D$Fsl  
VG#Q;Xd}  
//停止文件下载 sb'p-Mj  
public void siteStop() _pSIJ3O  
{ "=A|K~b  
bStop = true; B| Q6!  
for(int i=0;i<nStartPos.length;i++) 0$2={s4ze  
fileSplitterFetch.splitterStop(); K/Jk[29"\  
KO-a; [/  
MFTC6L+T  
} qeMv Vf  
} @+dHF0aXd  
//负责部分文件的抓取 oEAfowXSqk  
**FileSplitterFetch.java uL>:tb  
*/ eycV@|6u*  
package NetFox; 'rx?hL3VW  
6_ ]8\n  
^/{4'\p  
import java.io.*; e\~l!f'z  
import java.net.*; {8ECNQ[]  
cQ,9Rnfl,  
;o >WXw  
public class FileSplitterFetch extends Thread { Ej|A ; &E  
m0Z7N5v)  
"%kG RHq  
String sURL; //File URL c * 1S}us  
long nStartPos; //File Snippet Start Position 0UD"^zgY  
long nEndPos; //File Snippet End Position 1"$R 3@s;  
int nThreadID; //Thread's ID tDU}rI8?  
boolean bDownOver = false; //Downing is over M c@GH  
boolean bStop = false; //Stop identical )l{A{f6O  
FileAccessI fileAccessI = null; //File Access interface bs:QG1*.  
2[BA( B  
uRGB/ju^E  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Ps7_-cH  
{ @Mr}6x*  
this.sURL = sURL; s7|3zqi  
this.nStartPos = nStart; R2Yl)2 D  
this.nEndPos = nEnd; Jy`G]]?  
nThreadID = id; \-G5l+!  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 eE,;K1  
} O*4gV}:G  
?'f^X$aS  
6JWGu/A  
public void run() U6a z hi&,  
{ SW=aHM  
while(nStartPos < nEndPos && !bStop) 1t%<5O;R  
{  wQw-:f-  
`uhL61cMp  
.$^wy3:F"  
try{ ] ?9t-  
URL url = new URL(sURL); c 85O_J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r_=p,#}#  
httpConnection.setRequestProperty("User-Agent","NetFox"); .m!s". ?[  
String sProperty = "bytes="+nStartPos+"-"; sZEgsrJh  
httpConnection.setRequestProperty("RANGE",sProperty); E- KK  
Utility.log(sProperty); @>CG3`?}  
b.,$# D{p  
L"9 Gc  
InputStream input = httpConnection.getInputStream(); 1)gv%_  
//logResponseHead(httpConnection); 776 nWw)  
!*8#jy  
J 5- rp|  
byte[] b = new byte[1024]; 3z$HKG  
int nRead; L77EbP`P  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #Wq#beBb  
{ -sx-7LKi  
nStartPos += fileAccessI.write(b,0,nRead); VlV)$z_  
//if(nThreadID == 1) 8k%H[Smn:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Yd.027  
} ^^'[%ok  
=E; #OZO  
CHg]Ul  
Utility.log("Thread " + nThreadID + " is over!"); Z3Gm  
bDownOver = true; o6:45  
//nPos = fileAccessI.write (b,0,nRead); +&?'KZ+Z_v  
} l&$*}yCK  
catch(Exception e){e.printStackTrace ();} H}(=?}+  
} `TAcZl=8  
} 6l<1A$BQ  
I=K[SY,]9  
L[1d&d!p  
//打印回应的头信息 OAY8,C=M  
public void logResponseHead(HttpURLConnection con) oAC^4-Ld  
{ i@Vs4E[b  
for(int i=1;;i++) v=j>^F Z  
{ G u6[{u  
String header=con.getHeaderFieldKey(i); >]^>gUmq  
if(header!=null) Io09W^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 98jD"*W5  
Utility.log(header+" : "+con.getHeaderField(header)); E+:.IuXW$  
else G~O" /WM  
break; 2[XltjO  
} 0&f\7z  
} ~DK F%}E  
}]tFz}E\  
l~4_s/  
public void splitterStop() ::0aY ;D2  
{ G^ K*+  
bStop = true; AmgWj/>  
} >@z d\}@W  
j,Pwket  
m\1VF\  
} ~NA1SZ{Y+  
!+5C{Hs2  
4Fh&V{`W  
/* vP-3j  
**FileAccess.java NYGmLbq  
*//文件访问(定位,写) C+T&O  
package NetFox; 'n>EEQyp'  
import java.io.*; `D4oAx d9  
Ck:#1-t8{  
Al=(sHc'  
public class FileAccessI implements Serializable{ T4Xtuu1  
_r~!O$2  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 G OH  
RandomAccessFile oSavedFile; ,0BR-#  
long nPos;  4c  
#_on{I  
]sf2"~v  
public FileAccessI() throws IOException zoJ_=- *s  
{ Wk7L:uK  
this("",0); };i&a%I|  
} c6f|y_ 2  
D!c1;IHZ  
wwo(n$!\  
public FileAccessI(String sName,long nPos) throws IOException j!6elzg  
{ n9N#&Q"7m  
oSavedFile = new RandomAccessFile(sName,"rw"); $+A%ODv  
this.nPos = nPos; a|8| @,  
oSavedFile.seek(nPos); ,LoMt ]H  
} &b 5T&-C<  
vYYS .ve  
dK[*  
public synchronized int write(byte[] b,int nStart,int nLen) _{[k[]  
{ s*aH`M7^0  
int n = -1; +Gk! t]dy  
try{ '2 w XV;`  
oSavedFile.write(b,nStart,nLen); ,Le&I9*%  
n = nLen; Y;'VosTD  
} F_ ,L 2J  
catch(IOException e) ;r gH}r  
{ x-w`KFS  
e.printStackTrace (); AD~~e% s=  
} 5{8x*PSl  
pQk=x T  
[`y:M&@  
return n; C}n[?R  
} MMd0O X)P  
TS\9<L9S  
Uc_'3|e  
} LDT'FwMjy  
z0\;m{TH  
Y1#-^,qg  
/* oq=?i%'>  
**SiteInfoBean.java 7(yXsVq  
*/ <QYCo1_  
package NetFox; FE0qw1{qQ  
@SKO~?7T  
Y1$#KC  
public class SiteInfoBean { sN6 0o 7.  
6V.awg,  
MV Hz$hyB  
private String sSiteURL; //Site's URL l81&[  
private String sFilePath; //Saved File's Path 6(ka"Vu~  
private String sFileName; //Saved File's Name L@)b%Q@a  
private int nSplitter; //Count of Splited Downloading File R59e&   
3~cS}N T  
h5LJij J  
public SiteInfoBean() 4R K.Il*d  
{//nSplitter的缺省值为5 Bpk@{E9  
//default value of nSplitter is 5 >k$[hk*~  
this("","","",5); @ChN_gd3!  
} mXxZM;P[  
dNR7e   
r24\DvS  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ZcUh[5:|  
{ V-?sek{;  
sSiteURL= sURL; P@gu~!  
sFilePath = sPath; 8+*g4=ws  
sFileName = sName; DBu)xr}7A  
this.nSplitter = nSpiltter; EpFIKV!  
;J,,f1Vw  
g_rA_~dh  
} d[s;a.  
1?/5A|?V4+  
30sC4}   
public String getSSiteURL() ?F?\uC2)'  
{ j\XX:uU_  
return sSiteURL; S(g<<Te  
} "i!2=A8k  
&LCUoTzj  
2 ||KP|5@  
public void setSSiteURL(String value) %f_)<NP9=  
{ !~Hafn-1  
sSiteURL = value; (hhdbf  
} 5@w'_#!)  
BxSk%$J  
xm<5S;E5U4  
public String getSFilePath() :0J-ek.;  
{ gt2>nTJz.Z  
return sFilePath; eEZ|nEU  
} K B`1%=  
(&9DB   
#U ",,*2  
public void setSFilePath(String value) m~= ]^e  
{ DuTlYXM2^  
sFilePath = value;  2.HZ+1  
} 'U|MM;(  
9J-!o]f .b  
NDs]}5#   
public String getSFileName() 9 NGeh*`  
{ Z4wrXss~  
return sFileName; p%1xj2 ?nN  
} 7$q2v=tH_  
tF#b&za  
s8f3i\1  
public void setSFileName(String value) 6T{o3wc;  
{ *sc0,'0  
sFileName = value; wzNt c)~i  
} Q7 0**qm  
>/kPnpJ  
H 'WFORso[  
public int getNSplitter() h-?q6O/|  
{ `&|l;zsS  
return nSplitter; (/9.+V_  
} aIn)']  
+eV4g2w)  
jza}-=&+e  
public void setNSplitter(int nCount) }\`-G+i{W  
{ *0Wi^f  
nSplitter = nCount; H}jK3;8E  
} 1A`?y& Ll  
} 6]@|7|N>X  
i-i}`oN  
 MrKU,-  
/* |mQtjo  
**Utility.java )"pxry4v7J  
*/ <6}f2^  
package NetFox; c]g<XVI  
>'2w\Uk~:  
OIXAjU*N  
public class Utility { PtPGi^  
Dj,+t+|  
lt2Nwt0bv  
public Utility() Zgy2Pot  
{ .qb_/#Bas  
/C,>  
|ZST Y}RXA  
} ?|Q5]rhs  
Vtz yB  
//线程睡眠 .qqb> 7|q  
public static void sleep(int nSecond) \ ]kb&Qw  
{ Ye\*b? 6  
try{ {g!exbVf  
Thread.sleep(nSecond); _Pfx_+  
} #v~S",*.f  
catch(Exception e) Q#J>vwi=  
{ >F\rBc&  
e.printStackTrace (); XTi0,e]5{u  
} $3]E8t  
} (4{@oM#H6  
oQ-|\?{;A  
//日志 hD6ur=G8u  
public static void log(String sMsg) 02# b:  
{ FB =  
System.err.println(sMsg); ^qId]s  
} qV,$bw  
qy42Y/8'  
Zjp5\+hHV  
public static void log(int sMsg) eJ=Y6;d$  
{ u\1Wkxj  
System.err.println(sMsg); iRj x];:Vu  
} d4/`:?w  
} KWigMh\r  
zZ+LisSs&  
BJO~$/R?v  
/* _OknP2E  
**TestMethod.java Xb+if  
*/ q/w6sQx$  
package NetFox; T`w};]z^d2  
*09\\ G  
qK6  uU9z  
public class TestMethod { 21/a3Mlx#  
GdfK xSO  
'De'(I  
public TestMethod() m[xf./@f{  
{ ///xx/weblogic60b2_win.exe P=SxiXsr$  
try{ 9a~BAH,j  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); *p#YK|  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); XvzV lKL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ?/l}(t$H  
fileFetch.start(); Xv5Ev@T  
} Y(I*%=:$  
catch(Exception e){e.printStackTrace ();} |H+k?C-w  
3]kAb`9[K2  
C1P t3  
} ` .sIZku  
^K 77V$v  
.J6 j"  
public static void main(String[] args) 9J;H.:WH  
{ ^qzT5W\@  
new TestMethod(); Alk* "p  
} l~6SR  
} e2h k  
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