http断点续传简单实现（java)

/* Ab)7hCUW  
**SiteFileFetch.java 6P8X)3CE<T  
*/ $+j)  
package NetFox; 5kz`_\&  
import java.io.*; 4RNzh``u  
import java.net.*; }"v"^5  
3i1>EjML  
C0wq  
public class SiteFileFetch extends Thread { AnQRSB
(  
#e[5O|V~  
i\b2P2 `B  
SiteInfoBean siteInfoBean = null; //文件信息Bean :csLZqn[  
long[] nStartPos; //开始位置 M9nYt~vHX  
long[] nEndPos; //结束位置 o^_am>h  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 jLg4_N1SD  
long nFileLength; //文件长度 G.8ZISN/  
boolean bFirst = true; //是否第一次取文件 W:G*t4i  
boolean bStop = false; //停止标志 Wj0([n  
File tmpFile; //文件下载的临时信息 4k8 @u  
DataOutputStream output; //输出到文件的输出流 UF tTt`N2  
XR(kR{yo  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） t1S\M%?  
public SiteFileFetch(SiteInfoBean bean) throws IOException SV >EB;<  
{ q.4DwY5 L  
siteInfoBean = bean; BH^q.p_#>X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); t<-Iiq+tL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); cD]t%`*  
if(tmpFile.exists ()) ` $}[np|  
{ hk(^?Fp  
bFirst = false; HDYoM  
read_nPos(); PeOgXg)L`z  
} @U,cj>K  
else \VW.>@s~  
{ \%#jT GFs~  
nStartPos = new long[bean.getNSplitter()]; ^(y4]yZ  
nEndPos = new long[bean.getNSplitter()]; ufmFeeg  
} lxbZM9A2  
q;+qIV&.:  
1-`8v[S  
|dvcDx0|K  
} D*b> l_  
0>vm&W<?)  
ke0Vy(3t{h  
public void run() zK}.Bhj#  
{ -7CkOZT  
//获得文件长度 n']@Spm  
//分割文件 aDs[\'  
//实例FileSplitterFetch >PTq5pk  
//启动FileSplitterFetch线程 =
d9%ce  
//等待子线程返回 ]0o78(/w2  
try{ 4JucNGv  
if(bFirst) &"=inkh  
{ v+Hu=RZE  
nFileLength = getFileSize(); I3$v-OiL  
if(nFileLength == -1) % L]xar  
{ I;=}@]9  
System.err.println("File Length is not known!"); 8YCtU9D  
} 7:]I@Gc'  
else if(nFileLength == -2) u4%-e)$X  
{ -)w/nq  
System.err.println("File is not access!"); avdi9!J2  
} % 30&6"  
else gZ 9<H q  
{ CpA=DnZ  
for(int i=0;i<nStartPos.length;i++) XMpPG~XdN  
{ @D%VV=N~[  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 6x_8m^+m  
} }ZV$_  
for(int i=0;i<nEndPos.length-1;i++) 4!D!.t~r  
{ a&j H9  
nEndPos = nStartPos[i+1]; g8^$,  
} qz?9:"~$C  
nEndPos[nEndPos.length-1] = nFileLength; k9a-\UIMet  
}
VEJ Tw  
} ee6Zm+.B  
jQc$>M<"o  
S-My6'ar  
//启动子线程 u)%J5TR.Y  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
By%aTuV$  
for(int i=0;i<nStartPos.length;i++) V_h, UYN  
{ [<6ez;2q'  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~Xa >;  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), "@.hz@>  
nStartPos,nEndPos,i); r"^P>8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hX8;G!/  
fileSplitterFetch.start(); s %/3X\_  
} 5E4np`J  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IpHGit28  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Y'58.8hl  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ^dRB(E}|)  
nEndPos = " + nFileLength); zK?[6n89f  
// fileSplitterFetch[nPos.length-1].start(); $5(co)C  
.a?GC(  
%vgn>A?]1  
//等待子线程结束 j&u{a[Y/}  
//int count = 0; kowBB0  
//是否结束while循环 -:Y
x1Y3 [  
boolean breakWhile = false; y3kXfSe  
0rooL<~fa  
_>0I9.[5  
while(!bStop) W A-\2  
{ 'jqkDPn  
write_nPos(); 6ID@0  
Utility.sleep(500); ZE#A?5lb  
breakWhile = true; /aNlr>^  
sZA7)Z
`7  
fn;`Vit#  
for(int i=0;i<nStartPos.length;i++) l'm!e'7_  
{ _I+QInD;)  
if(!fileSplitterFetch.bDownOver) [Q6PFdQ_JT  
{ VI/77  
breakWhile = false; $zKf>[K  
break; RX\%R  
} Igrr"NuDZ  
} 2XNO*zbve  
if(breakWhile) h:[%' htz  
break; /5pVzv+rm  
^,*!Qk<c  
BRyrdt*_e  
//count++; tP^2NTs%]  
//if(count>4) Z0 @P1  
// siteStop(); !o1+#DL)MU  
} rUmaKh?v|X  
!E#FzY!}Pl  
nW
1u;.  
System.err.println("文件下载结束！"); \2#7B8  
} RR
|Z,  
catch(Exception e){e.printStackTrace ();} B'SLyf  
} QZw`+KR  
rvouE:  
+X
MK
Rt  
//获得文件长度 b"k1N9  
public long getFileSize() 4c0 =\v  
{ s
YE|  
int nFileLength = -1; :"{("!x  
try{ eaB6e@]@  
URL url = new URL(siteInfoBean.getSSiteURL()); rK(TekU
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _X;xW#go  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9(eTCe-~6  
WCRGqSr4  
+`=rzL"0I7  
int responseCode=httpConnection.getResponseCode(); WstX>+?'  
if(responseCode>=400) m9Xauk$
(  
{ #|-i*2@oR  
processErrorCode(responseCode); As"% u  
return -2; //-2 represent access is error VYG o;  
} DsX+/)d  
JP{Y Q:NF  
Z
W>iq M^9  
String sHeader; q!f'?yFYK  
cfSQqH  
Yc^;?n`x  
for(int i=1;;i++) 6
9+Pf*  
{ Xnc?o
T+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); -RI&uFqOI  
//Utility.log(in.readLine()); :yxP3e%rp  
sHeader=httpConnection.getHeaderFieldKey(i); !KC4[;Y  
if(sHeader!=null)  }o[NB  
{ "*8>` 6E  
if(sHeader.equals("Content-Length")) Q{=DLm`  
{ tY@+d*u  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); jEMnre3/  
break; ;suY
 
} q8S
HFKE  
} \$+#7( K  
else '/2)I8  
break; z#HNJAQ#|  
} b]5/IT)@O  
} mlLx!5
h=  
catch(IOException e){e.printStackTrace ();} R+r;V]-/
 
catch(Exception e){e.printStackTrace ();} {&TP&_|H  
9s4>hw@u  
{iXQUj  
Utility.log(nFileLength); pN=>q<]L  
6DVHJ+WTV  
x~?|bnM#3  
return nFileLength; 0d/ f4  
} ?Gx-q+H  
U+G8Hs/y  
ovk^  
//保存下载信息（文件指针位置） W4#E&8g%  
private void write_nPos() ^V0I!&7lx  
{ Ju-#F@38  
try{ D4jZh+_|
S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 
;iA$yw:  
output.writeInt(nStartPos.length); n#PXMD*  
for(int i=0;i<nStartPos.length;i++) Ug#EAV<m  
{ L_5o7~`0  
// output.writeLong(nPos); yk0^m/=C(  
output.writeLong(fileSplitterFetch.nStartPos); {Q021*xt/  
output.writeLong(fileSplitterFetch.nEndPos); bQ`2ll*(  
} wBCBZs$H  
output.close(); efK WR  
} C]a iu  
catch(IOException e){e.printStackTrace ();} 09 vm5|  
catch(Exception e){e.printStackTrace ();}
R^6]v`j;  
} \SooIEl@  
PG{"GiZz=  
)uO 3v  
//读取保存的下载信息（文件指针位置） E?h'OR@_ L  
private void read_nPos() 5Z>+NKQ  
{ ZMEYF!jN  
try{ ,8.zbr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); $Yj4&Two<  
int nCount = input.readInt(); *5mJA -[B+  
nStartPos = new long[nCount]; T5eJIc3a"  
nEndPos = new long[nCount]; ^S:I38gR#q  
for(int i=0;i<nStartPos.length;i++) QSx4M  
{ %GigRA@no  
nStartPos = input.readLong(); $r1{Nh  
nEndPos = input.readLong(); /6FPiASbS  
} X\|h:ce  
input.close(); _|>bOI  
} i\zN1T_  
catch(IOException e){e.printStackTrace ();} MZt&HbD-  
catch(Exception e){e.printStackTrace ();} DI\^&F)3T2  
} 42Cc`a%U  
}
LwKi-G?  
/Z2 g>  
private void processErrorCode(int nErrorCode) snVeOe#'S  
{ ;HmQRiCg  
System.err.println("Error Code : " + nErrorCode); ^.>XDUO F  
} S[y?>  
TUi<  
Q o
WjC  
//停止文件下载  L{u1_  
public void siteStop() $+n5l@W  
{ !}J19]\  
bStop = true; ?>iZ){0,  
for(int i=0;i<nStartPos.length;i++) ++CL0S$e  
fileSplitterFetch.splitterStop(); 8]&lUMaqVZ  
zfA"xD  
IWnyqt(k  
} k(wJ6pc  
} Dl_SEf6b  
//负责部分文件的抓取 |dqv
v  
**FileSplitterFetch.java u\@L|rh  
*/ GI/4<J\  
package NetFox; K@@Jt  
0hX@ta[Up  
]*\<k  
import java.io.*; baib_-$  
import java.net.*; pjNH0mZ  
fqZ+CzH  
C/!8NV1:4  
public class FileSplitterFetch extends Thread { B:tGD@  
Ts3(,
Y  
qR8 BS4q_p  
String sURL; //File URL dMoN1
9F  
long nStartPos; //File Snippet Start Position *Bx'g| u  
long nEndPos; //File Snippet End Position o88Dz}a  
int nThreadID; //Thread's ID f/e2td*A  
boolean bDownOver = false; //Downing is over >}B~~C;  
boolean bStop = false; //Stop identical z<s4-GJ)?  
FileAccessI fileAccessI = null; //File Access interface UdX aC= Q  
OuU]A[r  
?r}!d2:dX  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException FUKE.Ux
d  
{ u^uo=/
 
this.sURL = sURL; 9Jp"E5Ql)  
this.nStartPos = nStart; J9`[Qy\  
this.nEndPos = nEnd; Q)ZkUmW  
nThreadID = id; 0:k ~lz  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 *,p
16"Q;  
} Vr<ypyC  
D(gpF85t  
-QP&A >]7  
public void run() gfAVxMg  
{ 'gv7&$X}4  
while(nStartPos < nEndPos && !bStop) OvW/{  
{ My\  

V39)[FH}  
^1NtvQe@Y\  
try{ |cq%eN  
URL url = new URL(sURL); 0Z>oiBr4  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (r )fx  
httpConnection.setRequestProperty("User-Agent","NetFox"); -~ycr[}x  
String sProperty = "bytes="+nStartPos+"-"; m&Lc."  
httpConnection.setRequestProperty("RANGE",sProperty);  
kn|z  
Utility.log(sProperty); rFR2c?j8  
M)!:o/!cS  
s\i.pd:Q  
InputStream input = httpConnection.getInputStream(); Ue0Q| h  
//logResponseHead(httpConnection); 7Om)uUjU4  
P;
!4 VK  
QprzlxB  
byte[] b = new byte[1024]; <jRs/?1R  
int nRead; \^%5!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Y/w) V
V  
{ 9 ulr6  
nStartPos += fileAccessI.write(b,0,nRead); fO{E65uA  
//if(nThreadID == 1) B^G{k3]t  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IWcYa.=tZ  
} },5
_h0  
7w=%aW|  
S+C^7# lT  
Utility.log("Thread " + nThreadID + " is over!"); to*<W,I  
bDownOver = true; U[8Cg  
//nPos = fileAccessI.write (b,0,nRead); ()+;KF8  
} $W;IW$  
catch(Exception e){e.printStackTrace ();} U-EX)S^T[{  
} 0\y@etb:mf  
} c{t[iXDG  
u!DSyHR '  
X*'-^WM6  
//打印回应的头信息 ~ ]q^Akq  
public void logResponseHead(HttpURLConnection con) 'E,Bl]8C5  
{ ^ok;<fJ  
for(int i=1;;i++) (N\Zz*PLz  
{ ?$^qcpJCp  
String header=con.getHeaderFieldKey(i); hrRX=  
if(header!=null) A fctycQ-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); KCed!O
J+  
Utility.log(header+" : "+con.getHeaderField(header)); y]
`@%V2P  
else &xqr&(o  
break; B$
)6X  
} -zVa[&  
} :=tPC A=  
a4}2^K  
p=(;WnsK  
public void splitterStop() 1h+!<c q  
{ .>?["e#,  
bStop = true; iEki<e/  
} N)h>Ie  
H+3I[`v  
9VN@M  
} bYdC.AE  
.KT+,Y  
J6[x(T  
/* 4_N)1u !  
**FileAccess.java ja7Zv[  
*//文件访问(定位，写) %TG$5')0  
package NetFox; =b%J@}m`&  
import java.io.*; @mJN  
9'toj%XQ  
R/^JyL  
public class FileAccessI implements Serializable{ cT0utR
&  
L''0`a. +S  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 : 1fik  
RandomAccessFile oSavedFile; d<7J)zUm3  
long nPos; {C]M]b*F6(  
4rM77Uw>  
I9F[b#'Pn  
public FileAccessI() throws IOException }7=a,1T  
{ DhZtiqL#_  
this("",0); N0vd>b  
} 3^Yk?kFE  
\;7DS:d@  
FOk @W&  
public FileAccessI(String sName,long nPos) throws IOException >>$IHz4Z"  
{ RaU.yCYyu  
oSavedFile = new RandomAccessFile(sName,"rw"); !W%HAlUAG[  
this.nPos = nPos; X^|oY]D  
oSavedFile.seek(nPos); jm-0]ugY&`  
}
0dcXgP  
{my=Li<_H  
doR'=@ W  
public synchronized int write(byte[] b,int nStart,int nLen) (v4  
{ 5GJ0EZ'X  
int n = -1; ;2@sn+@  
try{ _kY5
6  
oSavedFile.write(b,nStart,nLen); zi?'3T%Ie  
n = nLen; 3yKI2en"  
} AVyZ#`,  
catch(IOException e) MW`a>'0t?  
{ K%pmE?%,8  
e.printStackTrace (); #dpt=  
} <,E*,&0W  
99ha
/t  
Q?a"uei[  
return n; 3,vH:L4  
} :):Y6)giBD  
/XSPVc<  
b(SV_.4,'  
} g?>AY2f[5  
/5x`TT  
T),:8/  
/* Nu_w@T\l  
**SiteInfoBean.java GwW#Ww;Oc  
*/ kQ#eWk J,  
package NetFox; 4C*3#/TR  
jVA~]a  
?UfZVyHv+  
public class SiteInfoBean { <{) 4gvH  
4
]B3C\ v  
^TEODKS  
private String sSiteURL; //Site's URL \W}EyA  
private String sFilePath; //Saved File's Path lTB!yF.r|  
private String sFileName; //Saved File's Name )2FO+_K?T  
private int nSplitter; //Count of Splited Downloading File tH'VV-!MZ  
vR)7qX}  
6fV)8,F3  
public SiteInfoBean() uWWv`bI>x  
{//nSplitter的缺省值为5 Un/fP1  
//default value of nSplitter is 5 %b{!9-n}  
this("","","",5); Iv<9})2K  
} z;/'OJ[.  
*SY4lqN  
~d8>#v=Q`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Pu^~]^W)  
{ 5i^vN"J  
sSiteURL= sURL; r{Q< a  
sFilePath = sPath; V^{!d
}  
sFileName = sName; xI<dBg|]+  
this.nSplitter = nSpiltter; f oVD+\~Y  
iTt=aQjd  
>1~`tP  
} +wUhB\F *  
GiZ'IDV  
yo.SPd="Vx  
public String getSSiteURL() ,>UmKrYo  
{ *i{.@RX?  
return sSiteURL; 8QN8bGxK   
} d*>k ]X@G  
n`}&,UA$4  
YgiGI <U  
public void setSSiteURL(String value) 2A%T!9J3  
{ 9-Qtj49  
sSiteURL = value; C%c `@="b  
} +2}(]J=-  
na3kHx@  
D&r8V;G[[  
public String getSFilePath() 8-5jr_*  
{ mG~y8nUtp  
return sFilePath; qE72(#:R*  
} -HsBV>C  
t4k'9Y:\Q  
iFCH$!  
public void setSFilePath(String value) I|IlFu?O=  
{ (A'q@-XQ  
sFilePath = value; <e&QTyb  
} aTh%oBrtP  
s~$4bN>LD  
(YJAT  
public String getSFileName() #=H}6!18  
{ JX)z<Dz$  
return sFileName; Cj1UD;  
} B^(rUR  
$l;t
P  
DiQkT R  
public void setSFileName(String value)  GQ0(&I  
{ W79A4l<  
sFileName = value; c'+r[rSn1  
} ;]M67ma7C  
'D"K`Vw  
R[9PFMn  
public int getNSplitter() (MoTG^MrBY  
{ OPY/XKyY,  
return nSplitter; i>Bi&azx  
} 6&QTVdK'O  
7 3z Y^x  
9H}iX0O  
public void setNSplitter(int nCount) A4Q)YY9~  
{ 6+;2B<II  
nSplitter = nCount; :ZfUjqRE  
} ,N7
l/6  
} ;vclAsJ  
Eb[H3v48,  
D'[P,v;Q  
/* _Q}RElA  
**Utility.java 4`-?r%$,:  
*/
31sgf5 s  
package NetFox; C$RAJ  
SxW}Z_8x  
p@
8^gc  
public class Utility { KO]?>>5S6  
l6B^sc*@  
gqd
B!l4  
public Utility() Pv-V7`{  
{ lzy$.H"W  
DET!br'z5  
VtzmY  
} !+45=d 5  
0"<;You  
//线程睡眠 %c&Ah  
public static void sleep(int nSecond) )|h;J4V  
{ <,X+
`m&  
try{ ?tC}M;~  
Thread.sleep(nSecond); g.Caapy  
} B mBzOk^  
catch(Exception e) /yw\(|T  
{ zj$_iB`9  
e.printStackTrace (); !:5`im;i  
} K?Xo3W%K  
} 1[/$ZYk:  
d[RWkk5  
//日志 vzyI::f?  
public static void log(String sMsg) !Ir1qt8T  
{ enbN0  
System.err.println(sMsg); KG-k$glD  
} ^8-~@01.`_  
k|$"TFXx;  
}u3H4S<o  
public static void log(int sMsg) /ro
mTK4  
{ jRdhLs,M9  
System.err.println(sMsg); i9@;,4f  
} ! F;<xgw  
} o9T@uWh+  
S1az3VJI\  
8MeO U  
/* .i3lG( YG  
**TestMethod.java ~^%0V<*-}  
*/ [aWDD[#j~  
package NetFox; ]w_  
ER;lkF`RF  
47C(\\
 
public class TestMethod { a*W_fxb  
%<=w[*i  
.o\;,l2  
public TestMethod() /Oq)3fU e  
{ ///xx/weblogic60b2_win.exe 4Wi8$  
try{  9
+'@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); yBPt%EF  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); jHu,u|e0>S  
SiteFileFetch fileFetch = new SiteFileFetch(bean); E~<(i':  
fileFetch.start();  d-ag  
} un$ Z7W/  
catch(Exception e){e.printStackTrace ();} T1Gp$l  
GCP{Z]u  
[xZ/ZWb/  
} C-a*EG  
aDN6MZM  
B@"SOX  
public static void main(String[] args) kW<Yda<a  
{ +7i7`'9pd  
new TestMethod(); I=4Xv<F  
} 8 l'bRyuS  
} >bX-!<S  
点击下载更多相关资料