http断点续传简单实现（java)

/* 0!4;."S  
**SiteFileFetch.java '5^$v{  
*/ $ghAC  
package NetFox; V[9#+l~#  
import java.io.*; * SAYli+@  
import java.net.*; bx!uHL=  
9NUft8QB  
\R"}=7  
public class SiteFileFetch extends Thread { Th!.=S{Y5  
T6/d[SH>  
! z!lQ~  
SiteInfoBean siteInfoBean = null; //文件信息Bean euxkw]`h6  
long[] nStartPos; //开始位置 hbZ]DRg  
long[] nEndPos; //结束位置 '(ZJsw  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Mn)>G36(  
long nFileLength; //文件长度 Oup5LH!sW  
boolean bFirst = true; //是否第一次取文件 iJ8 5okv'  
boolean bStop = false; //停止标志 tKr.{#)  
File tmpFile; //文件下载的临时信息 hMcSB8?  
DataOutputStream output; //输出到文件的输出流 g(X-]/C{  
'eM90I%(  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） ^Rel-=Z$B  
public SiteFileFetch(SiteInfoBean bean) throws IOException ^{ Kj{M22  
{ [G.4S5FX.]  
siteInfoBean = bean; 0<g;g%   
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); =D&xw2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 'A^;P]y  
if(tmpFile.exists ()) Z`_`^ \"  
{ 8}B*a;d  
bFirst = false; Cx N]fo  
read_nPos(); 2/*F}w/  
} #9R[%R7Nz  
else R,3E_me"}  
{ gzHMZ/31  
nStartPos = new long[bean.getNSplitter()]; @M]uUL-ze  
nEndPos = new long[bean.getNSplitter()]; 33R1<dRk  
} D)kh"cK*1  
UJ\[^/t  
^*6So3
 
}JP0q  
} ]^f7s36  
[H~Yg2O  
gKp5*  
public void run() bHJKX>@{  
{ >rbHpLm1`  
//获得文件长度 fPW|)e"  
//分割文件 ujlIWQU2mo  
//实例FileSplitterFetch '7'*+sgi$  
//启动FileSplitterFetch线程 Mz?xvP?z  
//等待子线程返回 V
XE85  
try{ \vH /bL  
if(bFirst) qcNu9Ih  
{ xgdS]Sz  
nFileLength = getFileSize(); 1q?b?.  
if(nFileLength == -1) ;8|D4+  
{ $0-}|u]5U  
System.err.println("File Length is not known!"); 7@[HRr  
} 8vk*",  
else if(nFileLength == -2) X
2RM*y|  
{ rP5&&Hso  
System.err.println("File is not access!");  <>|&%gmz  
} Lc&LF*  
else nZ4JI+Q)~  
{ 2s^9q9NS"  
for(int i=0;i<nStartPos.length;i++) o{W4@:Ib  
{ t)#dR._q  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 9/8#e+L  
} OpNTyKbaD  
for(int i=0;i<nEndPos.length-1;i++) S":55YQev!  
{ 7o+JQ&fF;  
nEndPos = nStartPos[i+1]; gY\g+df-  
} V`ODX>\  
nEndPos[nEndPos.length-1] = nFileLength; U<pGP  
} ;)6LX-  
} BLepCF38  
.=~-sj@k  
.5S< G)Ja  
//启动子线程 G}2DZ=&>'  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; {OH @z!+d  
for(int i=0;i<nStartPos.length;i++) {r.KY  
{ 2qA"emUM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), A^m]DSFOO  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), WxLmzSz{xD  
nStartPos,nEndPos,i); %OV)
O-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 46yq F  
fileSplitterFetch.start(); vU4Gw4  
} ]j4Nl?5*x  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), rXIFC
t8J  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6~oo.6bA  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", mY)Y47iL  
nEndPos = " + nFileLength); jD<fu  
// fileSplitterFetch[nPos.length-1].start(); _,"?R]MO  
f;PPB@ :`$  
\*wQ%_N5  
//等待子线程结束 TKwMgC}<[  
//int count = 0; E$4_.Z8sRw  
//是否结束while循环
Y:x,pPyl  
boolean breakWhile = false; ?k 4|;DD  
Dc1tND$X3g  
MV(Sb:RZ  
while(!bStop) ]* #k|>Fl  
{ V[Z^Z  
write_nPos(); wU"0@^k]<  
Utility.sleep(500); 0\y{/P?I$  
breakWhile = true; Lddk:u&J  
~Z{IdE  
x;w^&<hQ\  
for(int i=0;i<nStartPos.length;i++) .`ND  
{ P3W<a4 ==  
if(!fileSplitterFetch.bDownOver) #W]
4aZ1  
{ Bd8{25{c  
breakWhile = false; dF`\ewRFn  
break; +A!E 6+'  
} c; MF  
} Li?_P5+a  
if(breakWhile) &*
e(  
break; ycPGv.6  
qH8d3?1XO  
TwaK>t96[  
//count++; ,Fv8&tR  
//if(count>4) _MI8P/  
// siteStop(); 46(=*iT&V  
} H[x$65ND  
p`PBPlUn  
0DZ}8"2  
System.err.println("文件下载结束！"); )' hOW
*v  
} Q4[^JQsR2  
catch(Exception e){e.printStackTrace ();} C
j +{%^#  
} H}p5qW.tH:  
T, z80m}  
5gg Yg$  
//获得文件长度 $;V?xZm[  
public long getFileSize() zxo" +j4Ym  
{ rgK:ujzW!  
int nFileLength = -1; `"-ln'nw  
try{ \y^Ho1Fj  
URL url = new URL(siteInfoBean.getSSiteURL()); p$:ERI  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); SKUri  
httpConnection.setRequestProperty("User-Agent","NetFox"); \-h%z%{R  
MT3TWWtZ:  
f6*6*=  
int responseCode=httpConnection.getResponseCode(); HtN!Hgpwg  
if(responseCode>=400) C||9u}Q<  
{ Hf#VW^  
processErrorCode(responseCode); 6F)^8s02h  
return -2; //-2 represent access is error $GI
jWlAh  
} zZhA]J  
Nr(t5TP^  
YWK|AT-4  
String sHeader; `a+"[%  
;/79tlwq  
X9S`#N  
for(int i=1;;i++) 2d:5~fEJp  
{ G%q^8#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); BPwn!ii|  
//Utility.log(in.readLine()); wJr5[p*M  
sHeader=httpConnection.getHeaderFieldKey(i); nRSiW*;R  
if(sHeader!=null) #J):N  
{ gx55.}  
if(sHeader.equals("Content-Length")) xl]1{$1M  
{ FD*)@4<o  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); [e6zCN^t  
break; oLh2:c  
} _[:>!ekx  
} "gQ-{ W  
else JK/VIu&!  
break; /E32^o|,>  
} *%#Sa~iPo  
} $-Yq?
:  
catch(IOException e){e.printStackTrace ();} Af`qe+0E  
catch(Exception e){e.printStackTrace ();} 6`JY:~V"  
c2o.
H!>  
n5G|OK0,  
Utility.log(nFileLength); %p(!7FDE2n  
.:U`4->E  
-V_iv/fmM  
return nFileLength; s-[v[w'E  
} p7{%0
  
Pqtk1=U  
xk/osbKn  
//保存下载信息（文件指针位置） )zK6>-KWA  
private void write_nPos() CBrC   
{ N,
?4,+Hc-  
try{ $[*QsU%%  
output = new DataOutputStream(new FileOutputStream(tmpFile)); CwL8-z0 Jn  
output.writeInt(nStartPos.length); >69-[#P!  
for(int i=0;i<nStartPos.length;i++) 5Kw$QJ/  
{ /9 ^F_2'_  
// output.writeLong(nPos); K K_  
output.writeLong(fileSplitterFetch.nStartPos); %0MvCm  
output.writeLong(fileSplitterFetch.nEndPos); oj'a%mx  
} a:V2(nY  
output.close(); 2Vwv#NAV k  
} *)|EWT?,  
catch(IOException e){e.printStackTrace ();} IBn+42V  
catch(Exception e){e.printStackTrace ();} oWP3Y.  
} 0g{`Qd  
j YVR"D;  
;NJx9)7<  
//读取保存的下载信息（文件指针位置） 5IJm_oy  
private void read_nPos() 4b/>ZHFOF;  
{ }Tz<fd/  
try{ ^8q(_#w`K  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); d&x #9ka  
int nCount = input.readInt(); 5?=haGn  
nStartPos = new long[nCount]; a^xt9o`  
nEndPos = new long[nCount]; Gtm|aR{OS  
for(int i=0;i<nStartPos.length;i++) z,+LPr  
{ 6VQe
?oh  
nStartPos = input.readLong(); 921m'WE  
nEndPos = input.readLong(); IJQ" *;  
} O+w82!<:  
input.close(); nPRv.h  
} 
f[s|<U^  
catch(IOException e){e.printStackTrace ();} gbvMS*KQz  
catch(Exception e){e.printStackTrace ();} X?gH(mn  
} ,VYUQE>\  
@GyxO
c@6  
h|Ah\P?o  
private void processErrorCode(int nErrorCode) cq
So%a2  
{ NSV;R~"  
System.err.println("Error Code : " + nErrorCode); \\d!z-NOk?  
} "+sl(A3`U  
A(84cmq!q  
p2I
9t|  
//停止文件下载 P~^VLnw  
public void siteStop() DPg\y".4Y&  
{ WV?3DzeR  
bStop = true; "IuHSjP  
for(int i=0;i<nStartPos.length;i++) R[v
A
%G  
fileSplitterFetch.splitterStop(); - xE%`X  
7mBH#Q)  
?? 2x*l1  
} $O[$<D%H  
} |]UR&*  
//负责部分文件的抓取 $sS;#r0  
**FileSplitterFetch.java p*5QV  
*/ P ?A:0a  
package NetFox; VoG:3qN  
T?e(m  
NfsF'v  
import java.io.*; ?qt.+2:  
import java.net.*; /73ANQ"  
{4^NZTjd@  
, #nYHD  
public class FileSplitterFetch extends Thread { j#rj_uP  
dc=}c/6x  
x;@wtd*QB  
String sURL; //File URL Ej#pM.  
long nStartPos; //File Snippet Start Position !3;KC"o  
long nEndPos; //File Snippet End Position jM5w<T-2/  
int nThreadID; //Thread's ID uWjSqyb:  
boolean bDownOver = false; //Downing is over )C&'5z  
boolean bStop = false; //Stop identical uN*Ynf(:-  
FileAccessI fileAccessI = null; //File Access interface
;_iDiLC;  
{^*K@c  
;^f ;<  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException CBKLct>  
{ T)lkT?  
this.sURL = sURL; 4Je[!X@C  
this.nStartPos = nStart; =~P)7D6  
this.nEndPos = nEnd; oU)Hco"_k  
nThreadID = id; 08MY=PC~R  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (,XbxDfM  
} d9Uv/VGp  
N_liKhq  
~m6b6Aj@
6  
public void run() Z!foD^&R  
{ -PiakX  
while(nStartPos < nEndPos && !bStop) MG-

#p8  
{ 8k_cC$*Ng  
K'f`}y9  
G<W;HMj2  
try{ m'PU0x  
URL url = new URL(sURL); ]y\Wc0q  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); khQ@DwO*\=  
httpConnection.setRequestProperty("User-Agent","NetFox"); h]>7Dl]  
String sProperty = "bytes="+nStartPos+"-"; YwU[kr-i  
httpConnection.setRequestProperty("RANGE",sProperty); +[B@83  
Utility.log(sProperty); (,I9|  
T?k!%5,Kj  
?8!\VNC.  
InputStream input = httpConnection.getInputStream(); H#:Aby-d}  
//logResponseHead(httpConnection); w<SFs#Z  
IcJQC  
PdqyNn=  
byte[] b = new byte[1024]; ZE:!>VXa87  
int nRead; vJ9IDc|[  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) /I48jO^2  
{ =Y {<&:%(  
nStartPos += fileAccessI.write(b,0,nRead); :um]a70  
//if(nThreadID == 1) .X\9vVJ  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); z]HaE|j}S  
} 1{-yF :A
 
bZlKy`Z  
z2U^z
*n{  
Utility.log("Thread " + nThreadID + " is over!"); MRN=-|fV^  
bDownOver = true; aL^ 58My&  
//nPos = fileAccessI.write (b,0,nRead); g@|2z
  
} xU;/LJ6  
catch(Exception e){e.printStackTrace ();} V: n\skM  
} d=eIsP'h  
} FSD~Q&9&  
((AIrE>Rr  
BF/l#)$y
K  
//打印回应的头信息 =:*2t  
public void logResponseHead(HttpURLConnection con) +5"Pm]oRbx  
{ }!QVcu"+t/  
for(int i=1;;i++) ?p&( Af)  
{ :kKdda<g#  
String header=con.getHeaderFieldKey(i); ?bGk%jjHXM  
if(header!=null) h|%a}])G)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); zGtv(gwk  
Utility.log(header+" : "+con.getHeaderField(header)); nduUuCIY.  
else :$Xvq-#$|  
break; '1"vwXJ"  
} |a!]Iqz"N  
} @
kWRI*m  
z#*>u   
KD`*[.tT  
public void splitterStop() R q`j|tY  
{ Mhu|S)hn  
bStop = true; &P&VJLAe  
} Sf'uKSX1%  
D}~uxw;[^  
UIC~%?oIA  
} q$'D}OHT  
S*V!t=  
q,T4- E  
/* .&2~gA  
**FileAccess.java g4^3H
3Pd  
*//文件访问(定位，写) yY_#fJj  
package NetFox; zuS4N?t`p  
import java.io.*; PW+B&7{  
0]xp"xOwW  
gMsB1|  
public class FileAccessI implements Serializable{ |3G;Rh9w,  
vg8Yc  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 }"M5"?  
RandomAccessFile oSavedFile; |ZG0E  
long nPos; .'bhRQY  
^{a_:r"  
zs.@=Z"  
public FileAccessI() throws IOException H;MyT Vl  
{ `r]C%Y4?  
this("",0); =Q#d0Q  
} Ff1!+P,  
D"CU J?  
{a0yHy$H  
public FileAccessI(String sName,long nPos) throws IOException I
Xpn(vX  
{ Zp/$:ny  
oSavedFile = new RandomAccessFile(sName,"rw"); r3dGXiu  
this.nPos = nPos; ) uTFId  
oSavedFile.seek(nPos); \V T.bUs  
} hA1p#  
)]C(NTfxg  
d:{}0hmxI  
public synchronized int write(byte[] b,int nStart,int nLen) q!{>Nlk  
{ nh+Hwj#(x  
int n = -1; oSLm?Lu  
try{ Ey)ey-'\  
oSavedFile.write(b,nStart,nLen); D2I|Z  
n = nLen; (0["|h32,  
} 7Y5.GW\^  
catch(IOException e) :,V&P_  
{ Jwpc8MQ  
e.printStackTrace (); + />f?+  
} 06e dVIRr  
[1e]_9)p  
~l}\K10L*  
return n; !8&EkXTw,  
} >qZl s'  
gxmY^"Jy  
Xi;<O&+  
} aSMoee@!  
hQeG#KQ  
B.:1fT7lI  
/* z9E
*1B+  
**SiteInfoBean.java S$ k=70H  
*/ <m~{60{  
package NetFox; zKT4j1h  
[qU`}S2  
J,J6bfR/  
public class SiteInfoBean { CA5T3J@vAQ  
v.hQ9#:  
$HCgawQ  
private String sSiteURL; //Site's URL [eFJ+|U9  
private String sFilePath; //Saved File's Path .DM-&P  
private String sFileName; //Saved File's Name \h?6/@3ob  
private int nSplitter; //Count of Splited Downloading File K>TEt5  
0\V
)DV.i  
=#vJqA  
public SiteInfoBean() _9'hmej  
{//nSplitter的缺省值为5 qWJHb Dd  
//default value of nSplitter is 5 t N4-<6  
this("","","",5); / ;+Mz*  
} @w;$M]o1  
Oh%p1$H  
b!r%4Ah  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) @9
~x@[  
{ ^6J*:(eM  
sSiteURL= sURL; *4%%^*g.I  
sFilePath = sPath; 0rvBjlFT  
sFileName = sName; F` &W5[  
this.nSplitter = nSpiltter; WF:4p]0~)  
V9jxmu F,  
[^D>xD3B2  
} L1f=90  
x_CY`Y  
{< EPm&q  
public String getSSiteURL() O[\mPFu5  
{ R{ udV  
return sSiteURL; Tv6y+l  
} 9bhubx\^/  
=~5N/!  
tu(^D23  
public void setSSiteURL(String value) \01kK)  
{ ?Qx4Z3n  
sSiteURL = value; 'Va<GHr>+  
} .PV(MV  
J*38GX+  
\(--$9  
public String getSFilePath() /pV N1Yt  
{ 3Yo)K  
return sFilePath; '$rCV,3q  
} {+GR/l\!#  
!cdY`f6x  
K-@\";whF  
public void setSFilePath(String value) "$D'gSoYe  
{ ;&'ryYrex  
sFilePath = value; [!MS1vc;  
} yFS{8yrRUU  
RAnF=1[v  
1;'-$K`}  
public String getSFileName() ]
0BX5Z'  
{ R.DUfU"gp  
return sFileName; S^
D7}  
} *?$M=tH  
j dz IU  
X8ZO } X  
public void setSFileName(String value) 'IT]VRObP  
{ ~ch%mI~  
sFileName = value; 'Ebjn>"  
}
&=kb>*  
}!?RB v'W  
Gs,e8ri!  
public int getNSplitter() o';/$xrH  
{ y0ObcP.MA  
return nSplitter; ,LP^v'[V7  
} \Rb:t}  
y?P`vHf  
pw5{=bD  
public void setNSplitter(int nCount) k2tSgJW  
{ qj `C6_?  
nSplitter = nCount; |
)C*i  
} $rTb'8  
} 8Lgm50bs  
M<*WC{  
jVZ<i}h0B  
/* NUJ $)qNA  
**Utility.java ly35n`  
*/ JZ~wacDd  
package NetFox; %n GjP^  
:Ocw+X3  
[~X&J#  
public class Utility { Z[ &d2
'  
13w(Tf  
4T;<`{]  
public Utility() $d!Vxm  
{ M] +.xo+A  
bM5o-U#^ C  
d0C _:_  
} U]w"T{;@.)  
wW/q#kc  
//线程睡眠 X/90S2=P  
public static void sleep(int nSecond) c8Ud<M .  
{ z1 MT@G)S$  
try{ 6/?onEL9_  
Thread.sleep(nSecond); *,%$l+\h  
} u`.)O2)xU  
catch(Exception e) g

ujP{Z  
{ zx,9x*g  
e.printStackTrace (); 9thG4T8  
} psc Fb$b  
} LkP :l  
Xx%<rsA>F  
//日志 IGT9}24  
public static void log(String sMsg) SD{)Sq  
{ mw}Bl; - O  
System.err.println(sMsg); [p~,;%  
} >iRkhA=Vg  
&"I csxG  
V=% ;5/  
public static void log(int sMsg) __
FEdO  
{ >KvK'Mus/  
System.err.println(sMsg); ^Y+Lf]zz*  
} GN9kCyPK  
} kP^A~ZO.  
Crg'AB?  
?w'
86^_z  
/* 3fB]uq+eD%  
**TestMethod.java (Nk[ys}%*  
*/ P9f`<o  
package NetFox; 2<y9xvp  
<Z<meB[g  
a'/i/@h  
public class TestMethod { h.F=Fhx/1  
k4hk* 0Jq  
+xU({/  
public TestMethod() j7Ts&;`[*  
{ ///xx/weblogic60b2_win.exe rUmP_  
try{ S*|/txE'~Y  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \!BVf@>p%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 1^E5VG1[  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {jmy:e2  
fileFetch.start(); vNrn]v=|}7  
} Z b$]9(RS  
catch(Exception e){e.printStackTrace ();} Qubu;[0+a  
p

r7lm5  
`]XI Q\ *  
} 7pciB}$2
 
FVBAB>   
0V21_".S  
public static void main(String[] args) Bf;_~1+vLG  
{ `OWHf?t:  
new TestMethod(); y%;o  
} q~[sKAh  
} S#v
3%)R  
点击下载更多相关资料