http断点续传简单实现（java)

/* =]b9X7}  
**SiteFileFetch.java bl.EIyG>  
*/ B.K
4!/cF  
package NetFox; g1V)$s7  
import java.io.*; Qlh?
iA  
import java.net.*; )!,@m>0v{  
c&e0OV\m  
0;cuX@A/a?  
public class SiteFileFetch extends Thread { qZbHMTnT6  
cL7C2wB`  
P` ]ps?l  
SiteInfoBean siteInfoBean = null; //文件信息Bean PbEQkjE  
long[] nStartPos; //开始位置 +WLD  
long[] nEndPos; //结束位置 4Py3
I9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 b1)\Zi  
long nFileLength; //文件长度 }`]]b+_b>@  
boolean bFirst = true; //是否第一次取文件 ?O7iK<5N  
boolean bStop = false; //停止标志 (9
'be\  
File tmpFile; //文件下载的临时信息 <<<NXsH  
DataOutputStream output; //输出到文件的输出流 C P&o%Uc*  
`^%@b SE(  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） mu>] 9ZW  
public SiteFileFetch(SiteInfoBean bean) throws IOException 0_HJ.g!  
{ +7Rt{C,  
siteInfoBean = bean; 8]]@S"ZM,\  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); UM\}aq=,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); +wAp,Xr  
if(tmpFile.exists ()) y#e ?iE@  
{ |0]YA  
bFirst = false; U!NI_uk  
read_nPos(); )Y8qWJU  
} #G~wE*VR$  
else vX 1W@s  
{ nF|Oy0  
nStartPos = new long[bean.getNSplitter()]; z L8J`W  
nEndPos = new long[bean.getNSplitter()]; B G5X_s0/  
} B,MQ.|s[  
v^\JWPR/  
AoU_;B\b%  
'}CN?f|.  
} K4Y'B o4  

0<3E  
*?p ^6vO  
public void run() wBE7Bv45  
{ G ~A$jStm
 
//获得文件长度 <OIUyZS  
//分割文件

EoKo   
//实例FileSplitterFetch '(TmV#3  
//启动FileSplitterFetch线程 C$t.C rxx  
//等待子线程返回  }Zt.*%  
try{ Yfe'#MKfL  
if(bFirst) .Nk}Z9L]k  
{ L7<+LA)s0  
nFileLength = getFileSize(); !*5_pGe  
if(nFileLength == -1) PY2[S[  
{ ^glX1 )  
System.err.println("File Length is not known!"); N6WPTUQ1mF  
} B_!wutV@  
else if(nFileLength == -2) 9QC< E|  
{ C/bxfp{?  
System.err.println("File is not access!"); }\>+H  
} 3Fgz)*Gu]  
else eVrnVPkM  
{ 5`{=`  
for(int i=0;i<nStartPos.length;i++) O/(3 87=U  
{ [;*\P\Xih  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ^u3*hl}YKy  
} (X*'y*:  
for(int i=0;i<nEndPos.length-1;i++) 8>ESD}(  
{ uL bp.N8  
nEndPos = nStartPos[i+1]; xna7kA  
} l
},dQ4R  
nEndPos[nEndPos.length-1] = nFileLength; U7jhV,gO4  
} 3xP~~j;7  
} DQ%`v=  
33*^($bE&  
bAN10U  
//启动子线程 0,:iE\
 
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Fs?( UM  
for(int i=0;i<nStartPos.length;i++) DE5d]3B  
{ aXQ&@BZ{j  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K1/ U (A  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Tc9&mKVE%(  
nStartPos,nEndPos,i); 6euR'd^Qi  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); xT:qe  
fileSplitterFetch.start(); _MGNKA6JI  
} 2TE\4j  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), K/!/M%GB6  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,;9ak-$8p  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", v hRu`Yb  
nEndPos = " + nFileLength); "w>rlsT<O  
// fileSplitterFetch[nPos.length-1].start(); 4 U3C~J  
Y,3z-Pa=@  
Ii|uGxEc  
//等待子线程结束 H~~7~1"x  
//int count = 0; +G<}JJ'V  
//是否结束while循环 <9=zP/Q  
boolean breakWhile = false; J>><o:~@  
Q1aHIc  
eLCdAr  
while(!bStop) d^ 2u}^kG  
{ =9kj? u~  
write_nPos(); rdXCWK$E  
Utility.sleep(500); Rbx97(wK  
breakWhile = true; VI(RT-S6  
V*~1,6N[  
<]Ij(+J;  
for(int i=0;i<nStartPos.length;i++) &mX5&e  
{ d\v$%0  
if(!fileSplitterFetch.bDownOver) 83mlZ1jQz  
{ 6\; 4 4,3  
breakWhile = false; D=jSh  
break; C4&U:y<ju  
} xnJjCEZ  
} Dm7Y#)%8  
if(breakWhile) 6H(fk1E  
break; F% F c+?  
b=6MFPbg  
L!CX&
 
//count++; N BV}4  
//if(count>4) B'WCN&N  
// siteStop(); 1Z^`l6|2  
} +)/Rql(lY  
XNc"kp? z  
"Y
"t2l_n  
System.err.println("文件下载结束！"); oUW)H  
} @4 zi]v  
catch(Exception e){e.printStackTrace ();} w.4u=e >Z4  
} AzLbD2Pl  
tIn7(C  
Cfv L)f  
//获得文件长度 {0NsDi>(2  
public long getFileSize() c8bca`  
{ QU-7Ch#8  
int nFileLength = -1; .ujs`9d_-  
try{ e5*5.AB6&  
URL url = new URL(siteInfoBean.getSSiteURL()); m.\ >95!  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n/9 LRZD|w  
httpConnection.setRequestProperty("User-Agent","NetFox"); yj}bY?4I  
'Z*\1Ci  
[ 4?cM\_u@  
int responseCode=httpConnection.getResponseCode(); Jcwh|w9D8  
if(responseCode>=400) }<( "0jC  
{ w0a+8gexi  
processErrorCode(responseCode); Bi9 N  
return -2; //-2 represent access is error C:'WX*W  
} P?Gd}mdX?m  
6=Y3(#Ddt  
T[Z <bW~0  
String sHeader; d&PE,$XC  
fWtb mUq  
ZYwBw:y}y  
for(int i=1;;i++) {#dp-5V  
{ ~6@c]:  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); nvO%  
//Utility.log(in.readLine()); Lu8%qcC  
sHeader=httpConnection.getHeaderFieldKey(i); .RQXxw  
if(sHeader!=null) ;ZxK3/(7  
{ >\6jb&,%O  
if(sHeader.equals("Content-Length")) dvg;  
{ fd!pM4"0  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {<- ouD  
break; ~cO?S2!W  
} bik] JIM  
} g[=\KrTSg  
else {a+Fx}W
 
break; >j(I[_g  
} z._C*c  
} G:h;C].  
catch(IOException e){e.printStackTrace ();} I&'S2=s  
catch(Exception e){e.printStackTrace ();} q_9N+-?{7  
>0g`U  
{L-{Y<fke  
Utility.log(nFileLength); 4AJu2Hp  
WQIM2_=M  
#wh
O2Mv  
return nFileLength; i h`y0(<  
} gNEzl
x8A  
3IU$  
dFI.`pB  
//保存下载信息（文件指针位置） y7;XOPm  
private void write_nPos() m5'__<  
{ k"DQbUy0L  
try{ o3TBRn,  
output = new DataOutputStream(new FileOutputStream(tmpFile)); tvj'{W  
output.writeInt(nStartPos.length); /_zF?5h  
for(int i=0;i<nStartPos.length;i++) WoClT
b>F  
{ N) V7yo?  
// output.writeLong(nPos); lv
z:UWo  
output.writeLong(fileSplitterFetch.nStartPos); "b1R5
(Ar  
output.writeLong(fileSplitterFetch.nEndPos); T_oW)G  
} #/XK&(X  
output.close(); GH; F3s  
} *xZQG9`kt  
catch(IOException e){e.printStackTrace ();} uc"[qT(X  
catch(Exception e){e.printStackTrace ();} x%:>Ol  
} 1CS]~1Yp:  
.f.j >  
H,4,~lv|  
//读取保存的下载信息（文件指针位置） #r:Kg&W2FO  
private void read_nPos() y?R <g^A  
{ `MpC<sit  
try{ @=<TA0;LL  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I8-&.RE  
int nCount = input.readInt(); U*qK*"k  
nStartPos = new long[nCount]; "` ?Wu  
nEndPos = new long[nCount]; 'bY|$\I  
for(int i=0;i<nStartPos.length;i++) 1Z$99  
{ nE"b`  
nStartPos = input.readLong(); lA^Kh  
nEndPos = input.readLong(); <,]
CVo  
} `bt)'ERO%#  
input.close(); 2G:{FY  
} ~cg+BAfu  
catch(IOException e){e.printStackTrace ();} O,xAu}6f+  
catch(Exception e){e.printStackTrace ();} n5,Pq+[  
} W!Ct[t  
Uf
]Pd)D  
oj4)7{  
private void processErrorCode(int nErrorCode) ofrlTw&o  
{ vM4`u5  
System.err.println("Error Code : " + nErrorCode); sp|y/r#  
} ~PAbLSL*u  
v,.n/@s|X  
7!yF5+_d  
//停止文件下载 my\oC^/9  
public void siteStop() 3<'Q`H>  
{ fvBC9^3  
bStop = true; W2.1xNWO  
for(int i=0;i<nStartPos.length;i++) ! {o+B^^  
fileSplitterFetch.splitterStop(); R^O)fL0_  
jeuNTDjeL  
bg3jo
1J  
} jvKaxB;e  
} u$/2XO  
//负责部分文件的抓取 czsoD)N  
**FileSplitterFetch.java <.%8j\j(  
*/ om39;nk!}  
package NetFox; FEi,^V  
te4"+[ $|  
_nFvM'`<  
import java.io.*; |/Q."d  
import java.net.*; AA%g^PWpR  
j<-o{6r  
~S{\wL53  
public class FileSplitterFetch extends Thread { 9oN'.H^  
A(sx5Ynp  
LUVJ218p  
String sURL; //File URL (2\ekct ^  
long nStartPos; //File Snippet Start Position nPX'E`ut-V  
long nEndPos; //File Snippet End Position ^p%+rB.j[  
int nThreadID; //Thread's ID QS?9&+JM|  
boolean bDownOver = false; //Downing is over gY^TBR0?m  
boolean bStop = false; //Stop identical ,ui'^8{gK  
FileAccessI fileAccessI = null; //File Access interface f!Nc+  
{
ZI6!zh'  
=` >Nfa+,  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException s+G9L)b'  
{ t4W0~7  
this.sURL = sURL; 3'uES4+r  
this.nStartPos = nStart; ;8Q?`=a  
this.nEndPos = nEnd; _BaS\U%1(  
nThreadID = id; ]`U?<9~Ob  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 X \ZUt >  
} @9
tvN}  
05zdy-Fb  
4tu>~ vOE  
public void run() 0`zq*OQ  
{ yAkN2  
while(nStartPos < nEndPos && !bStop) (?wKBUi  
{ K4L#%KUPW  
NGGd6V%'-  
UsKn4Kh  
try{ "Z?":|%7  
URL url = new URL(sURL); 4B>|Wft{p]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ttt&sW`  
httpConnection.setRequestProperty("User-Agent","NetFox"); \:28z
  
String sProperty = "bytes="+nStartPos+"-"; +a@SdWf  
httpConnection.setRequestProperty("RANGE",sProperty); !t{!.  
Utility.log(sProperty); \zDV|n~{w  
;8kfgpM_  
Cagq0-:(p  
InputStream input = httpConnection.getInputStream(); 7-B'G/PS/  
//logResponseHead(httpConnection); %?wE/LU>  
t$%}*@x7  
l'R`XGT  
byte[] b = new byte[1024]; 'm((G4  
int nRead; `N,Jiw;bw  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) DzOJ{dF  
{ (acRYv(  
nStartPos += fileAccessI.write(b,0,nRead); -^N '18:  
//if(nThreadID == 1) +g30frg+Gl  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); EFOQ;q  
} ovVU%2o1b  
P1jkoJ  
6?~pjMV  
Utility.log("Thread " + nThreadID + " is over!"); l)bUHh5[  
bDownOver = true; F.hC%Ncu  
//nPos = fileAccessI.write (b,0,nRead); Dne&YVF9V  
} ,^T2hY`  
catch(Exception e){e.printStackTrace ();} 3<lDsb(}0A  
} Jl}7]cVq#  
} W5 }zJ)x  
W`kgYGnFG  
nQC[[G*x  
//打印回应的头信息 O^hV<+CX  
public void logResponseHead(HttpURLConnection con) 0eIR)#j*  
{ KcE=m\h  
for(int i=1;;i++) uEY5&wX`  
{ U)6
JJv  
String header=con.getHeaderFieldKey(i); {:cA'6f.b  
if(header!=null) c0~'5Mlp  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2Ev,dWV  
Utility.log(header+" : "+con.getHeaderField(header)); xDS9gGr  
else yuq E  
break; g;1 UZE;  
} "tIx$?I  
} T9 1Iz+j
 
9`{cX  
7[PXZT
  
public void splitterStop() x(Z@R\C-a  
{ 3m'6cMQ  
bStop = true; 'AU!xG6OQ  
} :4dili4|/  
LGkKR{ep(  
Bf.RYLsh6  
} 5y)kQ
<x"  
XN Y(@  
F&\o1g-L  
/* [g{}0[ew  
**FileAccess.java S70ERRk  
*//文件访问(定位，写) oj/tim  
package NetFox; BBDOjhik  
import java.io.*; n\ZFPXP  
!dGgLU_  
6 B )   
public class FileAccessI implements Serializable{ TCYnErqk  
%+.
]>''a  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 SaNx;xgi  
RandomAccessFile oSavedFile; B3D4fYQ  
long nPos; ^a]:G
Pc  
.F]6uXd  
E-/]UH3u H  
public FileAccessI() throws IOException I5Vp%mCY  
{ oU"!"t  
this("",0); \7]0vG  
} ePLpGT  
/h6K"w=='!  
;xqN#mqq  
public FileAccessI(String sName,long nPos) throws IOException EIdEXAC(  
{ |YEq<wbQ  
oSavedFile = new RandomAccessFile(sName,"rw"); P]cC2L@Vbi  
this.nPos = nPos; VCf/EkC  
oSavedFile.seek(nPos); x#)CH}J  
} r8%"#<]/  
I)]"`2w2w  
{$AwG#kt  
public synchronized int write(byte[] b,int nStart,int nLen) XSOSy2:  
{ q#
C;i
K4  
int n = -1; )wqG^yv  
try{ dQ#$(<v[  
oSavedFile.write(b,nStart,nLen); C"7-lz  
n = nLen; T@H<Fm_  
} ngLpiU0H&  
catch(IOException e) N1!O8"Q|*3  
{ wa1Qt  
e.printStackTrace (); H6/n  
} 9u0<$UY%  
|&u4Q /0  
}z,f8Yz  
return n; %^KN
Y ;E  
} 0]k-0#JM  
Gov]^?^D-  
3q-Xj:FP  
} nVyV]'-z  
1
[:tiTG|C  
Bcl6n@{2f  
/* ]iezwz`'  
**SiteInfoBean.java ;s\ck:Xg  
*/ N!lQ;o'  
package NetFox; .dPy<6E  
sD=iHO Am  
2 Q}^<^r  
public class SiteInfoBean { 1
|XC$0  
:meq4!g{1  
?v,4seRuz  
private String sSiteURL; //Site's URL pq +~|  
private String sFilePath; //Saved File's Path / n@by4;W  
private String sFileName; //Saved File's Name IeT1Jwe  
private int nSplitter; //Count of Splited Downloading File |C`.m
|  
]k)h<)nY  
jI!WE$dt  
public SiteInfoBean() _1ax6MwX  
{//nSplitter的缺省值为5 K<E|29t^k  
//default value of nSplitter is 5 6~+/cY-V  
this("","","",5); M0K+Vz=  
} \O=t5yS  
(5h+b_eB  
kWZ/O  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter)  %Z-B{I(  
{ p<8Ga.kiN  
sSiteURL= sURL; 9jf2b  
sFilePath = sPath; :O9i:Xq[QW  
sFileName = sName; -p*j9 z  
this.nSplitter = nSpiltter; bM>5=Zox  
dkAY%ztwo  
glUf.:]  
} &O\$=&, h  
#xNXCBl]O  
nO;t5d  
public String getSSiteURL() EZ)$lw/!J  
{ EF8'ycJk+  
return sSiteURL; ZnZ`/zNO  
} ~L?q.*q  
cIOM}/gqv  
Rdl^-\BV  
public void setSSiteURL(String value)
v~KgCLo  
{ K!qV82b='{  
sSiteURL = value; R}0xWPt9G  
} VjGtEIew  
Hq."_i{I  
+ieRpVg  
public String getSFilePath() &? z6f9*$  
{ l
Ql
  
return sFilePath; dZ{yNh.]  
} bFwc>  
f{ER]U  
u 4$$0 `  
public void setSFilePath(String value) 3fhlMOm  
{ >?)Df(n(9  
sFilePath = value; =N<Z@'c  
} 1%k$9[!l%  
B^lm'/,@  
C?fa-i0l^  
public String getSFileName() 65AG#O5R  
{ (@ixV$Y  
return sFileName; v|#}LQZ  
} ^gd[UC-"w  
&C6Z{.3V  
d'*:2;)g^  
public void setSFileName(String value) wC>Xu.Z:  
{ !)+8:8H'  
sFileName = value; 9vw0box  
} > ?<C+ZHh  
>Qold7 M  
;nZN}&m   
public int getNSplitter() W=ar&O~}n  
{ AD4Ot5  
return nSplitter; T Z_](%
 
} <
(<IRCR  
XfYhLE  
fFNwmH-jv  
public void setNSplitter(int nCount) 7<7 /NZ<I  
{ 3lT>C'qq  
nSplitter = nCount; iR6w)  
} k-XE
|v  
} z
cE[wM  
U6 $)e.FO  
P/;d|M(  
/* |)+;d  
**Utility.java jk-e/C  
*/ Yk!TQY4  
package NetFox; Z+]Uw  
& U6bOH%P  
60@]^g;$I  
public class Utility { xv:VW<  
0Z<&M|G  
$2lPUQZ<5  
public Utility() LH]<+Zren  
{ QM'Db`B  
E"[h20`\/  
@$ggPrs  
} "Acc]CqH*  
NsY D~n  
//线程睡眠 h(1o!$EU2  
public static void sleep(int nSecond) Od5I:p]N  
{ qTD^Vz V  
try{ Z<^TO1xs9B  
Thread.sleep(nSecond); AQ` `Dp  
} klwNeGF]N  
catch(Exception e) jt?.g'  
{ "0edk"hk  
e.printStackTrace (); z6+D=<  
} L/sMAB  
} H:jx_  

>*FHJCe  
//日志 h.ln%6:d  
public static void log(String sMsg) eG05}  
{ zIE{U  
System.err.println(sMsg); K,'v{wSr  
} ]`,jaD  
/-v6jiM  
.\6q\7Ej  
public static void log(int sMsg) mIy|]e`SJ  
{ ~ WO  
System.err.println(sMsg); <g4
[p^A  
} j[e<CGZ  
} {Jx-Zo>'  
W3.(s~)o  
N">4I)  
/* p6Ie?Gg  
**TestMethod.java , A@uSfC(  
*/ &uMx*TTY  
package NetFox; yJRqX]MLA  
tzn+ M0'  
:kb2v1{\  
public class TestMethod { Pn|;VCh  
1](PuQm7+  
rTmVHt  
public TestMethod() XGCjB{IV  
{ ///xx/weblogic60b2_win.exe  'K7m!y  
try{ )d$FFTH  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Ua2waA  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); *+|,rcI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); jo}yeGbU  
fileFetch.start(); |mp~d<&  
} !+(c/ gwBh  
catch(Exception e){e.printStackTrace ();} BV-(`#~:y  

T?+%3z}8  
uG){0%nX  
} 
KKcajN  
lh`ZEvt  
][TA7pDPV  
public static void main(String[] args) &ra2(S45  
{ r>;(\_@  
new TestMethod(); vi;yT.  
} vKFEA7  
} "969F(S$  
点击下载更多相关资料