http断点续传简单实现（java)

/* o9?@jjqH  
**SiteFileFetch.java eE;tiX/  
*/ -wlj;U  
package NetFox; J3Mb]X)_}  
import java.io.*; e5=d Ev  
import java.net.*;
9
N]Xa  
7*'/E#M  
MfTLa)Rz  
public class SiteFileFetch extends Thread { #c!:&9oU  
Nz{dnV{&x;  
rCyb3,W  
SiteInfoBean siteInfoBean = null; //文件信息Bean E$d3+``  
long[] nStartPos; //开始位置 aM^iDJ$>  
long[] nEndPos; //结束位置 k#*-<1  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 xVvUx,t  
long nFileLength; //文件长度 0oe<=L]F  
boolean bFirst = true; //是否第一次取文件 .{Y;6]9[  
boolean bStop = false; //停止标志 ]w
Q!ZG?)  
File tmpFile; //文件下载的临时信息
NOz3_k  
DataOutputStream output; //输出到文件的输出流 8WP>u8&  
$o6/dEKQ  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） Urj*V0^  
public SiteFileFetch(SiteInfoBean bean) throws IOException C3AWXO ^  
{ C2LPLquD+  
siteInfoBean = bean; ~PQ.l\C  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); NGra/s,9|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ~/:vr  
if(tmpFile.exists ()) h@)U,&  
{ KuNLu31%  
bFirst = false; WSThhI  
read_nPos(); +
,Dc0VC?  
} G#iQX`  
else A#uU]S  
{ WlL(NrVA@@  
nStartPos = new long[bean.getNSplitter()]; l,wlxh$}(  
nEndPos = new long[bean.getNSplitter()]; tz1@s nes  
} \lL[08G  
!+
xQ  
?}||?2=P  
SNEhP5!  
} c0Ug
5Vr  
gW,
[X(  
 a+h$u  
public void run() <+8'H:wz  
{ 0V%c%]PH  
//获得文件长度 6K2e]r  
//分割文件  *7Dba5B  
//实例FileSplitterFetch B6XO&I1c  
//启动FileSplitterFetch线程 tMr7d  
//等待子线程返回 &|SWy 2N  
try{ ]A4=/6`g?b  
if(bFirst) {+N< 9(O  
{ Z:b?^u4.  
nFileLength = getFileSize(); EZtU6kW"  
if(nFileLength == -1) A`c22Ls]  
{ ,"qCz[aDN1  
System.err.println("File Length is not known!"); "EW8ll7r  
} M,G
y.ivz  
else if(nFileLength == -2) :XKYfc_y  
{ ~G@NWF?7  
System.err.println("File is not access!"); [%IOB/{N  
} Da^q9,|  
else +a#&W}K  
{
;i{B,!#  
for(int i=0;i<nStartPos.length;i++) ,CE/o7.FG  
{ x"r0<RK  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); u ExLj6  
} T+8Yd(:hX  
for(int i=0;i<nEndPos.length-1;i++) ,n|si#  
{ <y 4(!z"  
nEndPos = nStartPos[i+1]; `RTxc  
} tZxx#v`  
nEndPos[nEndPos.length-1] = nFileLength; -oD,F $Rb  
} Bz+oMN#XJ  
} G,8mFH  
QE<Z@/V*a  
OqGp|`  
//启动子线程 (qcFGM22U  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 2j\_svw'  
for(int i=0;i<nStartPos.length;i++) [V}vd@*k  
{ :4AQhn^;"  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Fwm$0=BXL  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), z*3b2nV  
nStartPos,nEndPos,i); o'Bd. B  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 
6:1`lsP  
fileSplitterFetch.start(); tldT(E6  
} [i.@q}c~E  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), vrn4yHoZ  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); t]c<HDCK  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", YOxgpQ:i  
nEndPos = " + nFileLength); cS&KD@.  
// fileSplitterFetch[nPos.length-1].start(); O7.V>7Y9H  
UlXm4\@  
9~p;iiKGG  
//等待子线程结束 EPo)7<|>  
//int count = 0; ZbRRDXk!  
//是否结束while循环 )1<0c@g=  
boolean breakWhile = false; PW*Vfjf4  
x;ik   
5-dt0I@<  
while(!bStop) 'CBwE&AL  
{ 3j#VKj+Uc  
write_nPos(); H4i}gdR  
Utility.sleep(500); N$=YL @m8  
breakWhile = true; ,@Csa#  
;W0J  
0'&C5v'  
for(int i=0;i<nStartPos.length;i++) g%2G=gR$?z  
{ cGot0' mB  
if(!fileSplitterFetch.bDownOver) s
/1r{;q  
{ * :"*'  
breakWhile = false; YznL+TD  
break; _/[qBe  
} +|?a7qM  
} &BVUK"}P  
if(breakWhile) e\)%<G5  
break; ui]iOp  
q NGR6i  
4S(G366  
//count++; 6v@Prw@.b  
//if(count>4) R P{pEd  
// siteStop(); +o+f\!  
} K#FD$,c~  
L1IF$eC  
1$Up7=Dr=  
System.err.println("文件下载结束！"); A-x^JC=  
} 81RuNs]  
catch(Exception e){e.printStackTrace ();} aru2H6  
} g5BL"Dn  
cMK|t;" 3  
DVQr7tQf  
//获得文件长度 qw+7.h#V  
public long getFileSize() YB*)&@yx  
{ 5{H)r  
int nFileLength = -1; GtRpgM  
try{ +:A `e+\  
URL url = new URL(siteInfoBean.getSSiteURL()); 6Dd>ex!-A  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); k_g@4x1y*  
httpConnection.setRequestProperty("User-Agent","NetFox"); <?7CwW  
Z
@Rqm:e  
/
X8a3Eqp9  
int responseCode=httpConnection.getResponseCode(); mtUiO p  
if(responseCode>=400) COi15( G2  
{ m?-)SA  
processErrorCode(responseCode); w+m7jn!$  
return -2; //-2 represent access is error 5N9Cd[4  
} `JIp$  
9G6)ja?W  
33`bKKO}  
String sHeader; P IG,a~  
U=v>gNba  
>A
)Sl'  
for(int i=1;;i++) .)*&NY!nsl  
{ $`xpn#lz  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); c{'Z.mut  
//Utility.log(in.readLine()); \t{iyUx
Y  
sHeader=httpConnection.getHeaderFieldKey(i); Jq1oQu|rs  
if(sHeader!=null) 6@aH2+4+  
{ CI+)0=`<1B  
if(sHeader.equals("Content-Length")) x.t<@y~  
{ ;apLMMsWC  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); g.\b@0Uy'  
break; AB $N`+&
 
} Vc\
g"1x  
} F,YPIl  
else Iq|h1ie m+  
break; HX.K{!
5  
} Cq@7oi]W0  
} %>&~?zrq  
catch(IOException e){e.printStackTrace ();}  H_g
]q  
catch(Exception e){e.printStackTrace ();} ImQ-kz?b  
4#t'1tzu#  
&"u(0q  
Utility.log(nFileLength); 7Kym|Zg  
7$7|~k  
!19T=p/:$  
return nFileLength; -cUW,>E  
} :] Wn26z)  
"]^U(m>f  
w !kk(QMV  
//保存下载信息（文件指针位置） +sJ{9#6  
private void write_nPos() fe\'N4  
{ 8y<mHJ[B  
try{ I'D3~UIf  
output = new DataOutputStream(new FileOutputStream(tmpFile)); .(
&6gB  
output.writeInt(nStartPos.length); +R?E @S  
for(int i=0;i<nStartPos.length;i++) Gb2|e.z  
{ hzbvR~rn  
// output.writeLong(nPos); '3XOU.  
output.writeLong(fileSplitterFetch.nStartPos); l[ko)%7V  
output.writeLong(fileSplitterFetch.nEndPos); A@M2(?w4  
} g=KK PSK  
output.close(); hW~% :v  
} ^PdD-t
Y<  
catch(IOException e){e.printStackTrace ();} qY&(O`?m&  
catch(Exception e){e.printStackTrace ();} Cpzdk~+H  
} tzl,r"k3  
}P=FMme{F(  
!:d\A  
//读取保存的下载信息（文件指针位置） #WA7}tHb  
private void read_nPos() Eoz/]
b  
{ ym p*:
lH(  
try{ y**L^uvr  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q3r]T.].h  
int nCount = input.readInt(); };2Lrz9<  
nStartPos = new long[nCount]; !}A`6z  
nEndPos = new long[nCount]; 4PC'7V=S  
for(int i=0;i<nStartPos.length;i++) \>T1&JT  
{
]Y & 2&  
nStartPos = input.readLong(); z@~ZMk  
nEndPos = input.readLong(); 8<Nz34Y  
} 0?R$>=u  
input.close(); /3+E-|4s  
} 0$XrtnM  
catch(IOException e){e.printStackTrace ();} 'Q'-7z-6  
catch(Exception e){e.printStackTrace ();} yR F+
 
} `zs@W  
_2k<MiqCD[  
GDj_+G;tO\  
private void processErrorCode(int nErrorCode) yyPj!<.MGP  
{ p-C{$5& O1  
System.err.println("Error Code : " + nErrorCode); ILNghtm-  
} aorL,l  
AB!({EIi  
T5@t_D>8  
//停止文件下载 +=`w  
public void siteStop() {3Gj rE  
{ *~`oA~-Q  
bStop = true; : Q,O:  
for(int i=0;i<nStartPos.length;i++) Z(E.F,k  
fileSplitterFetch.splitterStop(); bz&9]%S<  
,0L< w
a  
VQ~eg wJL  
} I%?M9y.u6  
} 1_~'?'&^  
//负责部分文件的抓取 7Aw <:  
**FileSplitterFetch.java T~>&m~} +  
*/ U:/_T>f%  
package NetFox; v@X[0J_8  
Mc  
JjAO9j%  
import java.io.*; |bRi bB  
import java.net.*; ZZL%5{w_  
Y\H4.$V  
xAsy07J?  
public class FileSplitterFetch extends Thread { .<P@6Jq  
esTK4z]  
e?aSM  
String sURL; //File URL sx9[#6~{Y  
long nStartPos; //File Snippet Start Position (ds*$]  
long nEndPos; //File Snippet End Position fQU_
A  
int nThreadID; //Thread's ID a.<!>o<t:  
boolean bDownOver = false; //Downing is over @S012} xH  
boolean bStop = false; //Stop identical [o'}R`5)  
FileAccessI fileAccessI = null; //File Access interface Qe<c@i"  
Tq6@ 1j6p  
HV3D$~gF  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException wZ8LY;  
{  `Q^Vm3h  
this.sURL = sURL; k/xNqN(  
this.nStartPos = nStart; (w'k\y  
this.nEndPos = nEnd; [s!cc:JR
 
nThreadID = id; )o_$AbPt  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 @0:mP  
} }>Lz\.Z/+[  
ku
5g`ho  
"%t !+E>nr  
public void run() g.EKdvY"%H  
{ YAF0I%PYU  
while(nStartPos < nEndPos && !bStop) qr/N?,  
{ \AR3DDm  
6dCqS  
iu,Bmf^oD  
try{ 6? (8KsaN  
URL url = new URL(sURL); dZbG#4oO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Ks7k
aX  
httpConnection.setRequestProperty("User-Agent","NetFox"); hWu#}iN  
String sProperty = "bytes="+nStartPos+"-"; ?@_,_gTQ  
httpConnection.setRequestProperty("RANGE",sProperty); s&OwVQ<M  
Utility.log(sProperty); rNHV  
|z%*}DPrpa  
w<4){.dA  
InputStream input = httpConnection.getInputStream(); "Zicac@N  
//logResponseHead(httpConnection); I."4u~[  
~R W6;  
X"G3lG  
byte[] b = new byte[1024]; y+[wlo&WC  
int nRead; [2
6([H  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 2|^bDg;W+u  
{ ].w$b)G  
nStartPos += fileAccessI.write(b,0,nRead);
}oTac
 
//if(nThreadID == 1) ~&IL>2-B  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); E~!FEl;  
} K>$od^f%c  
D#9W [6  
_^ @}LVv+E  
Utility.log("Thread " + nThreadID + " is over!"); 0:Lm=9o  
bDownOver = true; cE=v566  
//nPos = fileAccessI.write (b,0,nRead); fx4X!(w!B  
} :@X@8j":  
catch(Exception e){e.printStackTrace ();} 8eoDE. }  
} Vi>kK|\b  
} {=d\t<p*n  
mE]W#?   
\oGZM0j  
//打印回应的头信息 D9&FCCiUE  
public void logResponseHead(HttpURLConnection con) aI8K*D )@  
{ `Uw^,r  
for(int i=1;;i++) J_mpI.^Bsf  
{ FCmS3KIa,  
String header=con.getHeaderFieldKey(i); Om2 )$(  
if(header!=null) L7*~8Y  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); BT+ws@|[  
Utility.log(header+" : "+con.getHeaderField(header)); 'x10\Q65[  
else \bb,gRfP  
break; !$+J7\&7p  
} |3g:q  
} m[u 6<C  
S,v9\wN.  
*%cI,}%   
public void splitterStop() Pz+8u&~p  
{ I|$_[Sw  
bStop = true; [H)p#x  
} n
mN6R
Gx  
A! 1>  
}g _#.>D+  
} SR S~s  
T ~t%3G  
6q8qq/h)  
/* { lLUZM  
**FileAccess.java U=%S6uL\bx  
*//文件访问(定位，写) fr\UX}o  
package NetFox; @,sg^KB  
import java.io.*; ? B^*YCo7(  
4 ITSDx  
Fk 1M5Dm  
public class FileAccessI implements Serializable{ TaB35glLY  
?Zoq|Q+  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 (N43?iv(  
RandomAccessFile oSavedFile;
H1=R(+-s  
long nPos; uBs[[9je(  
~GS`@IU}  
 PxK  
public FileAccessI() throws IOException {{=7mbc  
{ QkzPzbF"  
this("",0); `&>!a  
} YrgwR  
O`mW,  
z0Gh |N@)  
public FileAccessI(String sName,long nPos) throws IOException diqG8KaK  
{ P*(lc:  
oSavedFile = new RandomAccessFile(sName,"rw"); W?/7PVGv5h  
this.nPos = nPos; K)0 6][,  
oSavedFile.seek(nPos); s6).?oE  
} \"PlM!0du  
;mo}$^49*  
L1"X`Pz[}  
public synchronized int write(byte[] b,int nStart,int nLen) P5vMy'1X  
{ Ef$xum{  
int n = -1; -acW[$t  
try{  Jb {m  
oSavedFile.write(b,nStart,nLen); r0j:ll d  
n = nLen; *RM#F!A
 
} K|Yr  
catch(IOException e) m&|?mTo>m  
{ Q.6pmaXrb  
e.printStackTrace (); Ctt{j'-[  
} 1p9f& w  
'(u
[  
*Xl&N- 04  
return n; F=^vu7rf  
}  NP^kbF  
WFN5&7$W  
fX} dh9  
} C2eei're  
[>?B`1;@  
KY"W
{D9ib  
/* ^X0<ZI  
**SiteInfoBean.java lcIX l&  
*/ vM\8>p*U  
package NetFox; HPwmi[  
8u;l<^<  
c+|,2e 0T  
public class SiteInfoBean { %qfEFhRC  
>48zRi\N  
8<?60sj  
private String sSiteURL; //Site's URL "PJ@Q9n__  
private String sFilePath; //Saved File's Path 0-4WLMx  
private String sFileName; //Saved File's Name 2lHJ&fck<  
private int nSplitter; //Count of Splited Downloading File ='OPU5(;O  
a*S4rq@  
R[Kyq|UyVr  
public SiteInfoBean() KH2a 2  
{//nSplitter的缺省值为5 ^i#q{@g  
//default value of nSplitter is 5 cD2}EqZ 9  
this("","","",5); |3\ mH~Bw  
} {b+!0[  
](-:l6  
P*R`3Y,  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) \\x``*  
{ +~02j1Jx  
sSiteURL= sURL; 01#a  
sFilePath = sPath; =?T'@C  
sFileName = sName; @;d(>_n  
this.nSplitter = nSpiltter; aLuxCobV  
aeE9dV~  
T3)/?f?|  
} ^^)D!I"cA,  
A^ t[PKM"  
H`aqpa"C  
public String getSSiteURL() qV^,muyoG  
{ @y)-!MHN(8  
return sSiteURL; z+NXD4  
} VwHTtZ  
>,A:zbs&  
vQ26U(7\>  
public void setSSiteURL(String value) qeSxE`E"  
{ Uq0RJ<n  
sSiteURL = value; JyYg)f  
} 8KT|ixs  
m[Px|A5{  
x"5/1b3aq  
public String getSFilePath() *V3}L Z  
{ K )1K ]  
return sFilePath; <+" Jh_N#  
} US0)^TKrj  
S#_i<u$$  
}O5c.3  
public void setSFilePath(String value) z9YC9m)jK  
{ Y*B}^!k6  
sFilePath = value; {Qg"1+hhM  
} E,u@,= j  
L5of(gQ5]  
EM;]dLh  
public String getSFileName() u0#q)L8  
{ 2|kx:^D p  
return sFileName; r^VH [c@c  
} hf8=r5j=  
eB<R@a|?S  
/)MzF6  
public void setSFileName(String value) =MRg  
{ W!2(Ph*  
sFileName = value; 9]Uvy|  
} Bj;Fy9[yb  
AnfJyltS  
$^y6>@~  
public int getNSplitter() TJp(  
{ QrHI}r  
return nSplitter;
O:q 0-  
} = %\;7  
2r,K/'  
'h.{fKG]ME  
public void setNSplitter(int nCount) "<t/*$
42  
{ /H^=`[Mr  
nSplitter = nCount; x'+lNlv  
} /^ hB6_'D  
} yfnqu4Cn  
uK="#1z cC  
o2@8w[r  
/* O (<Wn-  
**Utility.java IE+$ET>t  
*/ KaZ*HPe(  
package NetFox; O+@"l$;N  
{Fta4D_1N  
d/+sR@\  
public class Utility { T""X~+{Z@  
5 b( [1*  
\vs,$h  
public Utility() L8Z[Ly+_  
{ 8tK8|t5+  
/KO!s,Nk  
s{2BG9s
 
}
LL7a20  
l&dHH_m3  
//线程睡眠 E#URTt:&>  
public static void sleep(int nSecond) #'mb9GWD3  
{ KxqT5`P&  
try{ !O-q13\Y  
Thread.sleep(nSecond); Ultx|qU  
} z%Op_Ddp  
catch(Exception e) <=/v%VXPm  
{ Ny/bNQS  
e.printStackTrace (); G0^WQQ4  
} -ytSS:|%\  
} #9,!IW]l  
4^1{UlCop  
//日志 xO`w|k  
public static void log(String sMsg) {  KE[8n  
{ muwXzN(KX  
System.err.println(sMsg); )Mx[;IwE  
} 5][Rvu0  
U#gHc:$  
Pwt4e-  
public static void log(int sMsg) x#|=.T  
{ f\!*%xS;  
System.err.println(sMsg); p{"p<XFyO  
} CeNpJ  
} .taJCE  
#r `hK)  
5H1SC8+B,  
/* IpXg2QbN  
**TestMethod.java %qcBM~efT  
*/ OY*BVJ^  
package NetFox;  L,!Z  
a\$PqOB!  
+[V[{n  
public class TestMethod { iNZ'qMH22  
@tdX=\[~  
g^26Gb.  
public TestMethod() ?D/r1%Z  
{ ///xx/weblogic60b2_win.exe D9B?9Qt2[  
try{ L}ud+Wfox  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); p#HPWW"  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); c=<d99Cu!  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )#l &F$  
fileFetch.start(); R|% 3JE0  
} B08q/qi  
catch(Exception e){e.printStackTrace ();} #m1e_[   
U
B@>i3  
Jvw~b\  
} %L+/GtxK  
S3PW[R@=  
F=kD/GCB  
public static void main(String[] args) ;TD<\1HJT=  
{ S])YU?e  
new TestMethod(); XtRfzqg?K  
} 12])``9  
} X&0m$x  
点击下载更多相关资料