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http断点续传简单实现(java)

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/* pr-!otz  
**SiteFileFetch.java MgLz:2 :F  
*/ CLD*\)QD\  
package NetFox; HgX4RSU  
import java.io.*; yHoj:f$$x  
import java.net.*; uEuK1f`  
'm"H*f  
!-4pr[C  
public class SiteFileFetch extends Thread { C`x>)wm:  
jX{lo  
$wVY)p9Q  
SiteInfoBean siteInfoBean = null; //文件信息Bean c>3W1"  
long[] nStartPos; //开始位置  Wcn^IQ  
long[] nEndPos; //结束位置 D058=}^HE  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 B: uW(E  
long nFileLength; //文件长度 'gE_xn7j  
boolean bFirst = true; //是否第一次取文件 G\IH b |  
boolean bStop = false; //停止标志 W"WvkW>-  
File tmpFile; //文件下载的临时信息 )5X7|*LP  
DataOutputStream output; //输出到文件的输出流 ?z60b=f8  
^IM;D)X&:  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) I#f<YbzD  
public SiteFileFetch(SiteInfoBean bean) throws IOException \Jv6Igu  
{ PHD$E s  
siteInfoBean = bean; 4oOe  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 58MBG&a%  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); YKUs>tQ!  
if(tmpFile.exists ()) ]0dp^%  
{ R m *"SG  
bFirst = false; ou-5iH?  
read_nPos(); D1lHq/  
} bd<zn*H Z*  
else Oy[t}*Ik  
{ J2H8r 'T  
nStartPos = new long[bean.getNSplitter()]; J(-#(kMyf  
nEndPos = new long[bean.getNSplitter()]; $X-,6*  
} Fu m1w  
q@u$I'`Bs  
h_d!G+-]  
qx53,^2  
} Z!|nc.  
/)y~%0  
poHDA=# 3  
public void run() '&T4ryq3"  
{ lTdYPqMi  
//获得文件长度 r"rID RQ"  
//分割文件 oc-7gz)  
//实例FileSplitterFetch hgKs[ySo,3  
//启动FileSplitterFetch线程 "mT~_BsD  
//等待子线程返回 bU:"dqRm<  
try{ K=Fcy#, f  
if(bFirst) sbNCviKP  
{ T0RgCU IV  
nFileLength = getFileSize(); +|( eP_  
if(nFileLength == -1) K22W=B)Ln  
{ )kgy L,9  
System.err.println("File Length is not known!"); ~&4,w9b)j  
} it>FG9hVo  
else if(nFileLength == -2) zYSXG-k  
{ haa [ob6T  
System.err.println("File is not access!"); Vv=d*  
} ?~S\^4]  
else _.FxqH>  
{ NRq jn; ,+  
for(int i=0;i<nStartPos.length;i++) >&U]j*'4  
{ kS?!"zk>  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); tp*AA@~  
} $+[HJ{  
for(int i=0;i<nEndPos.length-1;i++) )n|:9hc  
{ HcQ{ok9u  
nEndPos = nStartPos[i+1]; ~"}-cl,  
} 8u;l<^<  
nEndPos[nEndPos.length-1] = nFileLength; rmR7^Ycv/  
} a50{gb#  
} zc,fJM  
R0\E?9P  
U#,2et6  
//启动子线程 ;U}lh~e11  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; t]" 3vE>  
for(int i=0;i<nStartPos.length;i++) t91v%L   
{ }QG6KJh_%  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), HHoh//(\  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Z:9"7^+  
nStartPos,nEndPos,i); WRFzb0;01  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); W/{HZ< :.  
fileSplitterFetch.start(); +l&ZN\@0X  
} WZ"x\K-;  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), r#3_F=xL5  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); m]Z& .,bA  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", LfrS:g  
nEndPos = " + nFileLength); &HZ"<y{j  
// fileSplitterFetch[nPos.length-1].start(); 7PP76$  
i6(y Bn  
 +<AX 0(  
//等待子线程结束 `;4zIBJ  
//int count = 0; jcOxtDTSW  
//是否结束while循环 .#J'+LxFr  
boolean breakWhile = false; ;9 XM s)  
i~.L{K  
/[t]m,p$yq  
while(!bStop) =Q Otag1;  
{ `2d,=.X  
write_nPos(); PS!f&IY}[.  
Utility.sleep(500); ShHm7+fV  
breakWhile = true; cq % =DZ  
eA#J7=eC  
AVi w}Y J  
for(int i=0;i<nStartPos.length;i++) q}tLOVu1  
{ d5+ (@HSR  
if(!fileSplitterFetch.bDownOver) SS@# $t:  
{ #ra:^9;Es:  
breakWhile = false; SgFyv<6>:  
break; Y-@K@Zu]?  
} p?=rQte([  
} +!dIEt).U  
if(breakWhile) (PE"_80Z  
break; pvP|.sw5G  
ezCsbV;. [  
!2tZ@ p|  
//count++; x>;! `}x  
//if(count>4) )1Os+0az  
// siteStop(); zpiqJEf|'"  
} &T}~h^/t  
4vW:xK  
!YsL x[+  
System.err.println("文件下载结束!"); O,]t.1V  
} \qi=Us|=  
catch(Exception e){e.printStackTrace ();} xv9SQ,n<  
} XNf%vC>  
k P>G4$e_v  
6}n>Nb;L"  
//获得文件长度 Qp!r_a&  
public long getFileSize() a@lvn/b2  
{ tlQ3 BKp  
int nFileLength = -1; kdITh9nx<r  
try{ S;MS,R  
URL url = new URL(siteInfoBean.getSSiteURL()); d9sl(;r  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); iAbtv^fn  
httpConnection.setRequestProperty("User-Agent","NetFox"); mz3!HksZ "  
6#K1LY5}  
X'IW &^kI  
int responseCode=httpConnection.getResponseCode(); 'kL>F&|  
if(responseCode>=400) {Z3B#,V(g  
{ (p-a;.Twj  
processErrorCode(responseCode); N3TkRJZ  
return -2; //-2 represent access is error $F`jM/B6  
} =sPY+~<o  
3 =KfNz_  
q[ ] "`?  
String sHeader; pZuYmMP  
Txj%o5G  
a7)q^;:O  
for(int i=1;;i++) kNMhMEez  
{ Se%FqI  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j^"Z^TEBT  
//Utility.log(in.readLine()); mBhG"0:  
sHeader=httpConnection.getHeaderFieldKey(i); qi.|oL9p  
if(sHeader!=null) ;mu9;ixZ  
{ cx&jnF#$  
if(sHeader.equals("Content-Length")) Gyw@+(l  
{ `QC{}Oo^  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); n1a;vE{!  
break; \vs,$h  
} L8Z[Ly+_  
} 8tK8|t5+  
else L/1?PM  
break; 89Svx5S  
} k 9R_27F  
} l&dHH_m3  
catch(IOException e){e.printStackTrace ();} E#URTt:&>  
catch(Exception e){e.printStackTrace ();} #'mb9GWD3  
KxqT5`P&  
M6jP>fbV*  
Utility.log(nFileLength);  2(YZTaY  
<bDjAVq  
:G?"BL5vP  
return nFileLength; $Ud-aRlD  
} @ZK#Y){  
$M@SZknm  
p)(mF"\8=  
//保存下载信息(文件指针位置) .[? E1we  
private void write_nPos() FZ6.<wN  
{ :=UiEDN@  
try{ Psp3~Kg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ) **k3u t4  
output.writeInt(nStartPos.length); !Ui3}  
for(int i=0;i<nStartPos.length;i++) _Z~wpO}/  
{ ;<1O86!  
// output.writeLong(nPos); \O/EY&  
output.writeLong(fileSplitterFetch.nStartPos); E<1^i;F  
output.writeLong(fileSplitterFetch.nEndPos); !:,d^L!bh  
} kZs  
output.close(); ?>N82#9Q  
} ?"$W=*P\o  
catch(IOException e){e.printStackTrace ();} 4d)w2t?H%  
catch(Exception e){e.printStackTrace ();} ;``*]tY$  
} 3Wrl_V  
Ka1 F7b  
HU-4k/I~  
//读取保存的下载信息(文件指针位置) Hv>A$x$q  
private void read_nPos() iOm~  
{ L}ud+Wfox  
try{ p#HPWW"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); c=<d99Cu!  
int nCount = input.readInt(); C"PN3>x}j  
nStartPos = new long[nCount]; hun L V8z  
nEndPos = new long[nCount]; a5{CkM&,(  
for(int i=0;i<nStartPos.length;i++) #m1e_[   
{ UB@>i3  
nStartPos = input.readLong(); 6|r` k75.  
nEndPos = input.readLong(); : FF:{&d  
} Z'6 o$Xv  
input.close(); >|KfO>  
} JAj<*TB.%  
catch(IOException e){e.printStackTrace ();} aSi:(w  
catch(Exception e){e.printStackTrace ();} L`cc2.F  
} 7=N=J<]pl  
^QTl (L  
ICo_O] Ke  
private void processErrorCode(int nErrorCode) yHLc lv  
{ >P/kb fPA  
System.err.println("Error Code : " + nErrorCode); A0# K@  
} eC%.xu^  
Zk$AAjC&  
`W e M  
//停止文件下载 1wmS?  
public void siteStop() j 9XY%4.  
{ =<s+cM  
bStop = true; ,miU'<8tQ|  
for(int i=0;i<nStartPos.length;i++) Ne,7[k  
fileSplitterFetch.splitterStop(); _j-k*:  
)fP ,F(  
8X][TJG$  
} V=Iau_  
} B9KY$^J  
//负责部分文件的抓取 |jJC~/WR  
**FileSplitterFetch.java )I9AF,K  
*/ Y=sRVypJ  
package NetFox; Mii-Q`.:  
Na=9 ju  
I! {AWfp0  
import java.io.*; Wxkk^J9F3  
import java.net.*; Qf0$Z.-  
Gy.<gyK9  
17tph;  
public class FileSplitterFetch extends Thread { .qi$X!0  
aCcBmc  
S&}7jRH1  
String sURL; //File URL EShc1KPqc  
long nStartPos; //File Snippet Start Position 1el?f>  
long nEndPos; //File Snippet End Position Q4{%)}2$  
int nThreadID; //Thread's ID daE/v.a4|  
boolean bDownOver = false; //Downing is over @4^5C-  
boolean bStop = false; //Stop identical L^yQb4$&M  
FileAccessI fileAccessI = null; //File Access interface E D*=8 s2  
h']R P  
YN_#x  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException RQWVjF#  
{ t }7hD  
this.sURL = sURL; "B*a| 'n!  
this.nStartPos = nStart; ,w,>pO'[  
this.nEndPos = nEnd; #R4Mv(BG  
nThreadID = id; s+(%N8B  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7f8%WD)  
} H[@uE*W  
TyD*m$`y  
8jd<|nYnfc  
public void run() ~0w7E0DE[  
{ J5)e 7  
while(nStartPos < nEndPos && !bStop) 91r9RG>  
{ &eQzfx=|km  
C6,GgDH`  
p18-yt; 1  
try{ D-9zg\\'`  
URL url = new URL(sURL); ?aEBS  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 'Y(#Yxc  
httpConnection.setRequestProperty("User-Agent","NetFox"); gP/[=:  
String sProperty = "bytes="+nStartPos+"-"; D QP#h5O  
httpConnection.setRequestProperty("RANGE",sProperty); 2!\y0*}K  
Utility.log(sProperty); >&TSz5Q  
wXPNfV<(2  
FXV=D_G}  
InputStream input = httpConnection.getInputStream(); #x1AZwC  
//logResponseHead(httpConnection); @k <RX'~q  
qF`;xa%,}  
~"\sL;B  
byte[] b = new byte[1024]; o+;=C@,'  
int nRead; \=Af AO@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) zT#36+_?  
{ '!Ps4ZTn_  
nStartPos += fileAccessI.write(b,0,nRead); T~cq=i|O  
//if(nThreadID == 1) $^ (q0zR~l  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Iwi>yx8  
} <*0MD6 $5  
gGw6c" FRQ  
N#@xo)-H  
Utility.log("Thread " + nThreadID + " is over!"); 8A"[n>931  
bDownOver = true; DBAJkBs  
//nPos = fileAccessI.write (b,0,nRead); VH4P|w[YF  
} %}%D8-d}G  
catch(Exception e){e.printStackTrace ();} /O|!Sg{  
} ehtiu!Vk  
} (M4~N)7<P5  
>C+0LF`U  
3:<+9X  
//打印回应的头信息 Ky|Hi3?  
public void logResponseHead(HttpURLConnection con) Jme}{!3m  
{ B/q/sC  
for(int i=1;;i++) kF3 EJ  
{ c=I!?a"  
String header=con.getHeaderFieldKey(i); cBmo#:>'  
if(header!=null) 0 !9vGs  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); g-pDk*|I,Q  
Utility.log(header+" : "+con.getHeaderField(header)); ,r{*o6  
else 4U<'3~RN  
break; <]/`#Xgh  
} m}:";>?#  
} 2n?\tOm(V  
583ej2HPg  
#j d?ocoY  
public void splitterStop() ,a?)#X  
{ _Jk-nZgn  
bStop = true; SOb17:o3|  
} $JqdI/s  
~53E)ilB  
CEc& G  
} V:6#IL  
-Hh$3U v  
UYW%% 5p?  
/* v!t*Ng  
**FileAccess.java |o~FKy1'z\  
*//文件访问(定位,写) Vyj>&"28  
package NetFox; 1]A%lud4  
import java.io.*; $Bz|[=  
JnhHV(H  
q\O'r[&V  
public class FileAccessI implements Serializable{ E?y0UD[8J  
-yg9ug  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 _E)xR  
RandomAccessFile oSavedFile; \9Itu(<f  
long nPos; 9V?MJZ@aG  
AS|gi!OVA  
P0RM df  
public FileAccessI() throws IOException / Zz2=gDY  
{ qz E/n   
this("",0); QoDWR5*^D  
} ^*A/92!yF  
174H@   
fB1JU1  
public FileAccessI(String sName,long nPos) throws IOException miuJ!Kr'  
{ ]j*o&6cQf  
oSavedFile = new RandomAccessFile(sName,"rw"); Xu3^tH-b<  
this.nPos = nPos; _M:)x0("  
oSavedFile.seek(nPos); dLD"Cx  
} a&#Z=WK4  
1)#<nk)I  
~IE:i-Kz  
public synchronized int write(byte[] b,int nStart,int nLen) g]$>G0E`oD  
{ 5Ag]1k{  
int n = -1; $msT,$NJ  
try{ da\K>An>  
oSavedFile.write(b,nStart,nLen); s?~Abj_  
n = nLen; dT/Cn v=  
} uz>s2I}B  
catch(IOException e) m{pL< g^M  
{ (oq(-Wv  
e.printStackTrace (); @WhcY*R2  
} akm)X0!-}  
xVfJ ]Y  
uAzV a!)  
return n; "uGJ\  
} J9/9k  
s]L`&fY]O  
'QeqWn  
} '9auQ(2  
rM[Ps=5  
*Ei~2O}  
/* |YZ`CN<  
**SiteInfoBean.java QV{Nq=%]  
*/ <FS/'[P  
package NetFox; l:+tl/  
. Nog.  
4I:Jb;k>  
public class SiteInfoBean { (`3 Bi]7  
@=Ly#HuUM  
umrRlF4M;  
private String sSiteURL; //Site's URL <6dD{{J]>p  
private String sFilePath; //Saved File's Path 8Y5* 1E*  
private String sFileName; //Saved File's Name rRT9)wDa  
private int nSplitter; //Count of Splited Downloading File b\=0[kBQw  
;a{ Dr  
C9gF2ii|?  
public SiteInfoBean() deHBY4@  
{//nSplitter的缺省值为5 ywq{9)vq  
//default value of nSplitter is 5 Esw&ScBOP  
this("","","",5); jXZKR(L  
} a2dF(H  
.4_ ~ku  
g'pE z  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) =C`v+NPM)|  
{ rZJp>Q)s  
sSiteURL= sURL; G9E?   
sFilePath = sPath; g^B 6N F  
sFileName = sName; M/UJb1<  
this.nSplitter = nSpiltter; LYWQqxB  
iY;)R|6  
ucoBeNsHx  
} =b`>ggw#  
Oo7n_h1  
G92=b *x/  
public String getSSiteURL() N1LR _vS"  
{ XHN?pVZ7  
return sSiteURL; R#1m_6I  
} Hd;>k$B  
? ~_%I  
Lb2Bu>  
public void setSSiteURL(String value) NNe'5q9  
{ z W+wtYV4  
sSiteURL = value; ,0-   
} 4RTEXoXs  
Yn J=&21  
?_HTOOa  
public String getSFilePath() !o*oT}6n  
{ j:<E=[Kl  
return sFilePath; i]Kq  
} [W^6=7EO  
O~ qB  
?:U6MjlQ"{  
public void setSFilePath(String value) x!I7vs~~zW  
{ xg3G  
sFilePath = value;  4jG@ #  
} dr9I+c7u  
nHZ 4):`  
>St  
public String getSFileName() c:=Z<0S;  
{ I*ho@`U  
return sFileName; vKaX,)P;?  
} nH[@EL  
r43dnwX  
|nm,5gPNC  
public void setSFileName(String value) Yq1 ~"he8  
{ jRgv 8n  
sFileName = value; Q|pz].0  
} &=02.E@  
[=V8  
{`J7>K  
public int getNSplitter() J3q}DDnEo  
{ W:9L!+m^  
return nSplitter; v[Ar{t&  
} a 2).Az  
N18Zsdrp  
&3u* zV$  
public void setNSplitter(int nCount) Yt|{l  
{ v{%2`_c  
nSplitter = nCount; kP [ Y  
} 4AP<mo  
} :=~([oSNW"  
r-'j#|^tz  
R \`,Q'3  
/* \UNw43EL  
**Utility.java N:&^ql4  
*/ H 5sj% v  
package NetFox; [8)Zhw$  
t3bN P K^  
b,SY(Ce~g  
public class Utility { )ZiJl5l@  
%PkJ7-/b|^  
Rjh/M`|  
public Utility() t%8*$"~X  
{ N'[^n,\(:  
`D?vmSQ  
(a)d7y.oo  
} kyY tL_SD  
;PLby]=O  
//线程睡眠 -ud!j  
public static void sleep(int nSecond) /B1NcRS  
{ r--"JO%2  
try{ \&W~nYXq"  
Thread.sleep(nSecond); !FO||z(vb  
} sq :ff  
catch(Exception e) pLk?<y  
{ t,=khZ  
e.printStackTrace (); u1>|2D  
} N$_Rzh"9rr  
} @-u/('vpB  
K3\U'bRO  
//日志 L*L3;y|  
public static void log(String sMsg) uFECfh  
{ 6'*?zZrz  
System.err.println(sMsg); k6*2= xK~  
} Ng;E]2"  
W%Ky#!\-  
.;$/nz6vk  
public static void log(int sMsg) j_ :4_zdBy  
{ Iy`Zh@"~  
System.err.println(sMsg); 3YRhqp"E  
} gv<9XYByt  
} 4}?Yp e-  
A u(Ngq  
!xa,[$w(^  
/* <L5[#V_  
**TestMethod.java %JiA,  
*/ Vl'|l)b4W  
package NetFox; BBy/b c!  
8HTV"60hTs  
oYqlN6n,=6  
public class TestMethod { b]*9![_  
<Ep P;  
(u$Q  
public TestMethod() m2VF}% EIr  
{ ///xx/weblogic60b2_win.exe ~":?})  
try{ "-^TA_XfI  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); S W  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Af*^u|#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); u^V`Ucd"R  
fileFetch.start(); vp-)$f&  
} Pk*EnA)  
catch(Exception e){e.printStackTrace ();} 5z#>>|1>#  
-*tP_=-Dg  
J^1w& 40  
} 9Y*6AaKE6  
pspV~9,  
dr:)+R  
public static void main(String[] args) V&NOp  
{ ^$yr-p%-  
new TestMethod(); [l'~>  
} PsLuyGR.<  
} =;c? 6{<1  
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