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http断点续传简单实现(java)

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/* Dd5xXs+c  
**SiteFileFetch.java H ?`)[#  
*/ +F7<5YW&(  
package NetFox; 3?*M{Y|  
import java.io.*; s*)41\V0  
import java.net.*; xf^<ec  
Bd[L6J)  
pg?i F1  
public class SiteFileFetch extends Thread { e\A(#l@g  
n(Q\' ,C  
sR>`QIi(a  
SiteInfoBean siteInfoBean = null; //文件信息Bean m,@1LwBH  
long[] nStartPos; //开始位置 orB8Q\p'  
long[] nEndPos; //结束位置 KCJN<  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?9(o*lp  
long nFileLength; //文件长度 ~ gfA](N  
boolean bFirst = true; //是否第一次取文件 }l}yn@hYC  
boolean bStop = false; //停止标志 pVV}1RDa  
File tmpFile; //文件下载的临时信息 vhYMWfbY  
DataOutputStream output; //输出到文件的输出流 \=w'HZH#+  
4j=<p@  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) V{T{0b" \U  
public SiteFileFetch(SiteInfoBean bean) throws IOException c>R`jb@$N  
{ ` Y{>2UFX  
siteInfoBean = bean; { p!_-sL  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); "^9[OgE:  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); O/D Af|X|  
if(tmpFile.exists ()) mZbWRqP[|_  
{ cZDxsd]  
bFirst = false; y NrinYw  
read_nPos(); dcl.wD0~V  
} J+}+ "h~.  
else {ywXz|TP  
{ wUK7um  
nStartPos = new long[bean.getNSplitter()]; o9m  
nEndPos = new long[bean.getNSplitter()]; tIGVB+g{F  
} B=Zl&1  
lJ:M^.Em0  
d`9W  
jF38kj3O7  
} c?!YFm  
/lS+J(I  
/B,:<&_-  
public void run() RHwaJ;:)#  
{ =mHkXHE~:  
//获得文件长度 yHWi [7$  
//分割文件 KMK&[E#r  
//实例FileSplitterFetch IU Y> ih  
//启动FileSplitterFetch线程 :H!(?(Pie  
//等待子线程返回 @,x_i8  
try{ 6%gB E  
if(bFirst) Gh]_L+  
{ hncS_ZA  
nFileLength = getFileSize();  Y8)E]D  
if(nFileLength == -1) p~Hvl3SxR  
{ F-BJe]  
System.err.println("File Length is not known!"); N+CXOI=6x  
} NI5]Nz<?  
else if(nFileLength == -2) ?~"`^|d  
{ ^w:OS5%R  
System.err.println("File is not access!"); 0W T#6D  
} 5:Yck<  
else c Ndw9?Z  
{ .7 (DxN  
for(int i=0;i<nStartPos.length;i++) j>0<#SYBu  
{ ?w+ QbT  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); QP6z?j.  
} DR k]{^C~  
for(int i=0;i<nEndPos.length-1;i++) w`c0a&7  
{ \4h>2y  
nEndPos = nStartPos[i+1]; K-J|/eB  
} |Z`M*.d+  
nEndPos[nEndPos.length-1] = nFileLength; @gt)P4yE  
} \8;Qv  
} cS<TmS!  
Qw24/DJK  
Z69+yOJI  
//启动子线程 N#(jK1` y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 8{R_6BS  
for(int i=0;i<nStartPos.length;i++) rQ9*J   
{ )!'n&UxPo$  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), D 4< -8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ss? ]  
nStartPos,nEndPos,i); m"lE&AM64p  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); UF@IBb}0  
fileSplitterFetch.start(); #*!+b  
} t *{,Gk  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ![^EsgEB*  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); z 0~j  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", x}tKewdOSe  
nEndPos = " + nFileLength); #F_'}?09%  
// fileSplitterFetch[nPos.length-1].start(); FE/$(7rM  
zuUT S[  
i]it5  
//等待子线程结束 <=q*N;=T,  
//int count = 0; pu FXPw.3  
//是否结束while循环 + $>N]1  
boolean breakWhile = false; G1}~.%J  
1#grB(p?  
p/r~n'g$  
while(!bStop) {mNdL J  
{ ?n!lUr$:y  
write_nPos(); 4\p$4Hs}  
Utility.sleep(500); ;aq`N}d  
breakWhile = true; vG Y!4@[  
Y4QLs^IdB  
p3g4p  
for(int i=0;i<nStartPos.length;i++) Xo2^N2I  
{ Mv|vRx^b  
if(!fileSplitterFetch.bDownOver) p1+7 <Y:  
{ |y.zo cBj  
breakWhile = false; r=h8oUNEJ*  
break; K!GUv{fp  
} Z[Wlyb0  
} JW=uK$sO  
if(breakWhile) Yt -W1vl  
break; @4;&hP2Z:  
m7JPH7P@BM  
h ~ $&  
//count++; 4[`[mE18.  
//if(count>4) {5>3;.  
// siteStop(); -  $%jb2  
} r,5-XB  
$4=Ne3 y  
7'Lp8  
System.err.println("文件下载结束!"); >A3LA3( c  
} }/20%fP  
catch(Exception e){e.printStackTrace ();} y =R aJm  
} NdZ)[f:2  
0f1H8zV  
P*0f~eu  
//获得文件长度 wTT RoeJ}  
public long getFileSize() 9hy'DcSy,  
{ XM$GQn]B  
int nFileLength = -1; ~L~]QN\3  
try{ u=%y  
URL url = new URL(siteInfoBean.getSSiteURL()); @8|Gh]\P  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); hGvqT,'  
httpConnection.setRequestProperty("User-Agent","NetFox"); ,s0 9B  
@d&g/ccMxd  
Rfht\{N 7  
int responseCode=httpConnection.getResponseCode(); <KtBv Ip]  
if(responseCode>=400) 5:c;RRn  
{ sc%dh?m7  
processErrorCode(responseCode); `4LJ;KC(  
return -2; //-2 represent access is error aVP5%  
} VUp. j  
D3y>iQd   
wS V@=)H\:  
String sHeader; l8^y]M  
q-YL]PgV  
x@Y|v@}BE  
for(int i=1;;i++) 6J\q`q(W(  
{ |~eY%LB  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L;3aZt,#O  
//Utility.log(in.readLine()); [<yz)<<  
sHeader=httpConnection.getHeaderFieldKey(i); PB+\jj  
if(sHeader!=null) 5C B%=iL{  
{ g92dw<$>  
if(sHeader.equals("Content-Length")) Hq?&Qo  
{ u#FXW_-TK  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); VgA48qZ  
break; 0(8gQ 2n  
} QWw"K$l  
} ;u,rtEMy;  
else ^#;RLSv   
break;  //<:k8  
} p5-<P?B  
}  DwXU  
catch(IOException e){e.printStackTrace ();} pw3 (t  
catch(Exception e){e.printStackTrace ();} S;8.yj-  
6}ftBmv  
 ;1@C_5C  
Utility.log(nFileLength); ';6X!KY+]  
^sV|ck  
.Vmtx  
return nFileLength; + 8f>^*:u  
} ~T02._E  
+`| mJa  
<7^Kt7k  
//保存下载信息(文件指针位置) Ir27ZP  
private void write_nPos() @0|nq9l1  
{ z?kd'j`FG  
try{ \-OC|\{32  
output = new DataOutputStream(new FileOutputStream(tmpFile)); D"cKlp-I6|  
output.writeInt(nStartPos.length); D^u\l  
for(int i=0;i<nStartPos.length;i++) D-pX<0 -y  
{ >! oF0R_<  
// output.writeLong(nPos); 1i3V!!r  
output.writeLong(fileSplitterFetch.nStartPos); >$uUuiyL4  
output.writeLong(fileSplitterFetch.nEndPos); "U{,U`@?  
} pDOM:lGya  
output.close(); oIb) Rq!m  
} Y 9i][  
catch(IOException e){e.printStackTrace ();} < eQ[kM  
catch(Exception e){e.printStackTrace ();} 5mavcle{4r  
} sL i*SR  
3u_oRs  
b@ 6:1x  
//读取保存的下载信息(文件指针位置) Fc'[+L--Q  
private void read_nPos() \5hw9T&[B  
{ fLNag~  
try{ o8{<qn|  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); W`x)=y]Z  
int nCount = input.readInt(); 1~@|e Wr|  
nStartPos = new long[nCount]; RM,'o[%  
nEndPos = new long[nCount]; OR;&TbWF(R  
for(int i=0;i<nStartPos.length;i++) _R74/|  
{ =Z`0>R`  
nStartPos = input.readLong(); >A($8=+#x  
nEndPos = input.readLong(); U Du~2%  
} t8vc@of$c,  
input.close(); ;&kn"b}G;  
} iNJAZ6@+  
catch(IOException e){e.printStackTrace ();} 6vobta^w  
catch(Exception e){e.printStackTrace ();} \Yq0 zVol  
} "0-y*1/m  
qlUzr.^-  
B+46.bIH  
private void processErrorCode(int nErrorCode) ! =WcF5  
{ h<Wg3o  
System.err.println("Error Code : " + nErrorCode); ,QvYTJ{  
} F7T E|LZ  
TatMf;?h&  
KO&:06V{  
//停止文件下载 H&bh<KPMh  
public void siteStop() 7/"@yVBW  
{ yp+F<5o  
bStop = true; P}@*Z>j:#  
for(int i=0;i<nStartPos.length;i++) a#y{pT2 b  
fileSplitterFetch.splitterStop(); dB3N%pB^  
%S`ik!K"I  
~ziexZ=N  
} E >}q2  
} JZ=5Bpw  
//负责部分文件的抓取 {ma;G[!  
**FileSplitterFetch.java 4SR(->@  
*/ kA^A mfba  
package NetFox; a,n93-m(m  
gz61FW  
5B*qbM  
import java.io.*; $.:3$et@/  
import java.net.*; fHfY}BQS  
|I^y0Q:K  
!SF^a6jT  
public class FileSplitterFetch extends Thread { J8;Okzb!L  
dy:d=Z  
^ ulps**e  
String sURL; //File URL K-(;D4/sQE  
long nStartPos; //File Snippet Start Position d>!p=O`>{q  
long nEndPos; //File Snippet End Position H$tb;:  
int nThreadID; //Thread's ID 5v9uHxy  
boolean bDownOver = false; //Downing is over N9]xJgTze  
boolean bStop = false; //Stop identical 4ht\&2&:  
FileAccessI fileAccessI = null; //File Access interface O]qPmEj  
/9_#U#vhY  
`?uPn~,e8  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +< KNY  
{ "}zda*z8  
this.sURL = sURL; &fSTR-8ev#  
this.nStartPos = nStart; xl2g0?  
this.nEndPos = nEnd; LgHJo-+>  
nThreadID = id; m r4b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 "'A"U  
} :woa&(wN;1  
r )b<{u=]  
{?i)K X^  
public void run() a)S7}0|R  
{ C).2gQ G  
while(nStartPos < nEndPos && !bStop) O >FO>  
{ Km*<Kfcz  
lIh[|]  
7Fl-(Nv`  
try{ " H1:0p  
URL url = new URL(sURL); Ei~f`{i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); QlD6i-a  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7lU.Ni t  
String sProperty = "bytes="+nStartPos+"-"; 2U9&l1P=  
httpConnection.setRequestProperty("RANGE",sProperty); %&<W(|U1<  
Utility.log(sProperty); a)9rs\Is{  
16$y`~c-z  
&p"(-  
InputStream input = httpConnection.getInputStream(); 3hS6j S  
//logResponseHead(httpConnection); l h/&__  
M<[ ?g5=#  
CgnXr/!L  
byte[] b = new byte[1024]; VXIQw' Cq  
int nRead; XP;x@I#l  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ~>%DKJe  
{ <xn;bp[  
nStartPos += fileAccessI.write(b,0,nRead); de YyaV  
//if(nThreadID == 1) |(ocDmd  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Z;b+>2oL  
} A}G|Yfn  
-3hCiKq  
Q)^g3J  
Utility.log("Thread " + nThreadID + " is over!"); ow.6!tl0=h  
bDownOver = true; x~/+RF XF  
//nPos = fileAccessI.write (b,0,nRead); onl>54M^  
} g:gB`8w?  
catch(Exception e){e.printStackTrace ();} ^\wl2  
} inF6M8 A1  
} A/ 0qk  
J_ J+cRwq  
[xdj6W  
//打印回应的头信息 - DL"-%X.  
public void logResponseHead(HttpURLConnection con) HXks_ix )  
{  Q2\  
for(int i=1;;i++) [ rdsv  
{ ',mW`ZN  
String header=con.getHeaderFieldKey(i); S()Za@ [a$  
if(header!=null) s[c^"@HT  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); )+Y&4Qu  
Utility.log(header+" : "+con.getHeaderField(header)); hI~SAd ,#A  
else !k<:k "7  
break; ]rW8y%yD  
} TnE+[.Qu  
} /F~X,lm*~  
+R[4\ hC0Y  
J_xG}d  
public void splitterStop() #@Y/{[s|@  
{ 2k1aX~?  
bStop = true; QnKC#   
} _Bk U+=|J  
)saR0{e0N  
tWD|qg_  
} 9?`RR/w  
O9]\Q@M.  
LSkk;)'2K  
/* XDLEVSly7  
**FileAccess.java i_U}{|j  
*//文件访问(定位,写) kh?. K#  
package NetFox; Eark)  
import java.io.*; gyus8#sT  
@@} `hii  
zvf3b!}  
public class FileAccessI implements Serializable{ [7W(NeMk  
$a.u05  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _CdROo6I  
RandomAccessFile oSavedFile; {}\CL#~y  
long nPos; GLh]G(  
D1X{:#|  
^M Ey,  
public FileAccessI() throws IOException BaL]mIx  
{ A=`* r*  
this("",0); <qY5SV,  
} crn k|o  
CLK^gZ  
p4mY0Y]mP  
public FileAccessI(String sName,long nPos) throws IOException ]T^ is>  
{ 6 = gp:I  
oSavedFile = new RandomAccessFile(sName,"rw"); Hg(5S,O2  
this.nPos = nPos; y\[r(4h  
oSavedFile.seek(nPos); JO1 ,TtA  
} Ew4 g'A:H  
x9V {R9_gf  
ULl_\5s2  
public synchronized int write(byte[] b,int nStart,int nLen) y1C/v:;  
{ lbkL yp2  
int n = -1; #T% zfcUj  
try{ _413\`%8?  
oSavedFile.write(b,nStart,nLen); xzk}[3P{  
n = nLen; z="L4  
} Y @}FL;3  
catch(IOException e) D4Sh9:\  
{ uva\0q  
e.printStackTrace (); l$XA5#k  
} XxOn3i  
xo~g78jm7,  
H;I~N*ltJ(  
return n; Z.Pi0c+  
} }gCHQ;U7`  
POGw`:)A  
M#M?1(O/NE  
} |I1+"Mp  
|Fv?6qw+  
2k+16/T  
/* -e*BqH2t  
**SiteInfoBean.java v2J0u:#,  
*/ :s*>W$Wp4  
package NetFox; _4R,Ej}  
{L9yhYw  
j>!sN`dBj  
public class SiteInfoBean { Kbas-</Si  
"DjU:*'  
`P.CNYR<J  
private String sSiteURL; //Site's URL K^H>~`C=  
private String sFilePath; //Saved File's Path Z[} $n-V  
private String sFileName; //Saved File's Name "$8w.C  
private int nSplitter; //Count of Splited Downloading File &;v!oe   
;BI)n]L  
YzV(nEW  
public SiteInfoBean() K0<yvew  
{//nSplitter的缺省值为5 k18$JyaG  
//default value of nSplitter is 5 e &3#2_  
this("","","",5); *Nlu5(z  
} O5;-Om  
o!Fl]3F  
H#+xKYrp  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) tpU D0Z)  
{ <SQ(~xYi  
sSiteURL= sURL; QS\ x{<e/  
sFilePath = sPath; }m_t$aaUc1  
sFileName = sName; @^CG[:|  
this.nSplitter = nSpiltter; {!=2<-Aq  
r}EM4\r  
uaxB -PZ  
} :qnokrGzB  
1nB@zBQu -  
sqG`"O4W  
public String getSSiteURL() J@` 8(\(  
{ DHzkRCM  
return sSiteURL; 7;xKy'B\  
} q\H7& w  
JZ K7uB,X  
xG%*PNM0q  
public void setSSiteURL(String value) F+*Q <a4  
{ %6]\^  
sSiteURL = value; 4oJ$dN  
} U**)H_S/~  
Nza; O[  
J3&Sj{ o  
public String getSFilePath() JS7dsO0;  
{ (C\r&N  
return sFilePath; *?N<S$m  
} <E}N=J'uJ  
)ddsyFGW  
P6we(I`"2  
public void setSFilePath(String value) + *a7GttU  
{ IJIQ" s  
sFilePath = value; ~:Ixmqi}R  
} hbnS~sva  
iGa}3pF  
.. UoyBV  
public String getSFileName() <[9?Rj@  
{ (nz}J)T&  
return sFileName; :c<*%*e  
} SG`)PW?  
~04[KG  
)* 3bkKVB  
public void setSFileName(String value) ,s? dAy5  
{ Ff)@L-Y\K  
sFileName = value; P;c0L;/  
} 8[HZ@@  
NL-_#N$  
R&!]Rl9hf  
public int getNSplitter() +-P<CCvWz  
{ i[_| %'p  
return nSplitter; o=mo/N4  
} pK"&QPv  
D1ZC&B_}-  
/.v_N%*-v  
public void setNSplitter(int nCount) 4d-q!lRpa  
{ Hf_'32e3<  
nSplitter = nCount; * gHCy4u{  
} [` 9^QEj  
} *;X-\6  
;NG1{]|Z  
Gl;f#}  
/* xFX&9^Uk  
**Utility.java ['t8C  
*/ 6KB^w0oA  
package NetFox; /f]/8b g>  
K @C4*?P  
hiIya WU  
public class Utility { ,`"K  
+,wWhhvlzv  
_XWnS9  
public Utility() <S{7Ro  
{ e?1KbJ?.  
m0C{SBn-M  
0@v 2*\D#  
} UAKu_RO6S  
lG 8dI\`  
//线程睡眠 %r P !  
public static void sleep(int nSecond) S ;h&5.p  
{ x97H(*  
try{ wo]ks}9  
Thread.sleep(nSecond); oX*b<d{\N  
} Y2D >tpqNw  
catch(Exception e) [%? hCc  
{ sL8>GtVo  
e.printStackTrace (); ;L$,gn5H  
} d.I%k1`(  
} g41<8^(  
#@q1Ko!NZ  
//日志 1~L\s}|2d  
public static void log(String sMsg) 5f{wJb2  
{ FR(QFt!g  
System.err.println(sMsg); w_!%'9m>  
} 2$Wo&Q^_  
Onyh1  
n5\}KZh  
public static void log(int sMsg) w -M7opkq  
{ > '.[G:b  
System.err.println(sMsg); vuW-}fY;  
} JeL~]F  
} 18rp; l{  
-`g J  
2;h+;G  
/* 1Df, a#,y"  
**TestMethod.java %2,/jhHL  
*/ :-U53}Iy  
package NetFox; tStJ2-5*t  
]6q*)q:`  
St_S l:m$  
public class TestMethod { k1m'Ka-  
^} tuP  
s*eyTm  
public TestMethod() }9 ?y'6l  
{ ///xx/weblogic60b2_win.exe ]An_5J  
try{ xjE7DCmA  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _V&x`ks  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *cPN\Iu.W  
SiteFileFetch fileFetch = new SiteFileFetch(bean); yduuFK  
fileFetch.start(); wZ O@J|  
} ^t7_3%%w  
catch(Exception e){e.printStackTrace ();} 7<vy;"wB  
!9PX\Xbn  
8M~u_`6  
} vU7&'ca  
EFeAr@nj  
A^t"MYX@  
public static void main(String[] args) R7,p ukK  
{ B9AbKK$`  
new TestMethod(); b70AJe=  
} vLr&ay!w  
} {x|MA(NO  
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