http断点续传简单实现（java)

/* >~})O&t  
**SiteFileFetch.java
Tb!jIe  
*/ Rg 5kFeS  
package NetFox; #pk  
import java.io.*; @k\npFKQm  
import java.net.*; rVB\\  
dg4q+  
1B~[L 5p9  
public class SiteFileFetch extends Thread { 5?|yYQM0tK  

hx8.  
!CR#Fyt+9  
SiteInfoBean siteInfoBean = null; //文件信息Bean d*l2x[8}g-  
long[] nStartPos; //开始位置 )^m"fQ+  
long[] nEndPos; //结束位置 R+tQvxp#  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Rln% Y  
long nFileLength; //文件长度 eDsc_5I  
boolean bFirst = true; //是否第一次取文件 0+Q;a  
boolean bStop = false; //停止标志 URj2 evYW  
File tmpFile; //文件下载的临时信息 abg`:E  
DataOutputStream output; //输出到文件的输出流 *@g>~q{`  
Gq{);fq  
//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） om8`^P/b  
public SiteFileFetch(SiteInfoBean bean) throws IOException 5?8jj  
{ H.&"
~eH  
siteInfoBean = bean; 6)_h'v<|M  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); NB3ar&.$S  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); W('V2Z-q  
if(tmpFile.exists ()) #^xj"}o@  
{ ~$m:j];  
bFirst = false; l{hO"fzy  
read_nPos(); VCa`|S?2  
} 'LC0hoV  
else ?%Gzd(YEY  
{ "-g5$v$de  
nStartPos = new long[bean.getNSplitter()]; \ `|  
nEndPos = new long[bean.getNSplitter()]; 6`Diz_(  
} QUWx\hqE  
{g
I%-  
$j/#IzD1D  
]:~z#k|2@6  
} oVY_|UujG  
~{l @
  
[I78<IJc  
public void run() $.3J1DU  
{ x57O.WdN  
//获得文件长度 S+GW}?!  
//分割文件 /hAy1V6  
//实例FileSplitterFetch 3 V$ \s8  
//启动FileSplitterFetch线程 ,e;_ Vb  
//等待子线程返回 afd.v$63  
try{ synueg  
if(bFirst) qq>Qi(>  
{ p']{WLDj2  
nFileLength = getFileSize(); .@@&q4=&  
if(nFileLength == -1) ),5A&qT*  
{ a|Wrc)UR  
System.err.println("File Length is not known!"); ^tI4FQ>Y  
} x]vyt}oCmk  
else if(nFileLength == -2) Q$A;Fk}-  
{ .7> g8  
System.err.println("File is not access!"); bZu2.?{  
} tkW7wP;  
else =1zRm >m  
{ |l:,EA_v|  
for(int i=0;i<nStartPos.length;i++) fHXz{,?/w  
{ U_~r0  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8}?w%FsN#  
} !&pk^VFl+  
for(int i=0;i<nEndPos.length-1;i++) W$:D#;jz`h  
{ p/KG{-f,  
nEndPos = nStartPos[i+1]; ]*<!|;q  
} ! l"*DR  
nEndPos[nEndPos.length-1] = nFileLength; 76b2 3|  
} bpdluWS+)  
} rN`-ak  
e5m]mzF@  
Dw.Pv)'$  
//启动子线程 kg^5D3!2{Q  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]P)2Q!X  
for(int i=0;i<nStartPos.length;i++) QG5)mIJ  
{ JY$+<`XM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Vs(D(d,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), lVgin54Q  
nStartPos,nEndPos,i); UH#S |

o4  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); n_4BNOZ~  
fileSplitterFetch.start(); F **/T  
} P7*?E*   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), c!]yT0v&s  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6k;>:[p
 
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", '%*/iH6<U{  
nEndPos = " + nFileLength); /~P4<1  
// fileSplitterFetch[nPos.length-1].start(); =Q4Wr0y><]  
f!J?n]  
CQ'4 ".7  
//等待子线程结束 wc?YzXP+  
//int count = 0; 0xUn#&A~  
//是否结束while循环 I?CfdI  
boolean breakWhile = false; !}=#h8fv  
;upYam"  
)zu m.6pT  
while(!bStop) \:E=B1  
{ OhTd>~R`<  
write_nPos(); GP_%.fO\M  
Utility.sleep(500); ;9hS_%ldX4  
breakWhile = true; *ch7z|wo.  
G@rV9  
fT5vO.
a  
for(int i=0;i<nStartPos.length;i++) .cs4AWml<  
{ O[z-K K<  
if(!fileSplitterFetch.bDownOver) LcGG~P|ML  
{ G1ED=N_#  
breakWhile = false; lSBu,UQP  
break; ?y,z  
} K.42 VM)F  
} +7j7zpw  
if(breakWhile) oFp4*<\  
break; AhQsv.t   
v[<;z(7Qk  
E<77Tj  
//count++; ^-%O  
//if(count>4) N9=?IFEe]  
// siteStop(); pW-aX)\DR  
} ||'A9  
X"S")BQ q  
#%.fsJNA$  
System.err.println("文件下载结束！"); _"lW  
} jB3Rue:+g  
catch(Exception e){e.printStackTrace ();} "T~A*a^  
} "2hs=^&8  

Y >U_l:_^  
/v7o!D1G  
//获得文件长度 CB>*(Mu  
public long getFileSize() P5`BrY,hZ  
{ 2I0Zr;\f  
int nFileLength = -1; =S|dzgS/  
try{ oe{,-<yck  
URL url = new URL(siteInfoBean.getSSiteURL()); 
u9G
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (XQ:f|(  
httpConnection.setRequestProperty("User-Agent","NetFox"); {3K`yDF  
/N=M9i
\;  
SD]rYIu+  
int responseCode=httpConnection.getResponseCode(); zS!+2/(  
if(responseCode>=400) zj7?2  
{ (RI+4V1  
processErrorCode(responseCode); A(ZtA[G  
return -2; //-2 represent access is error ;oVFcZSA  
} ;f9a0Vs  
)\QPUdOvx  
5k`Df/  
String sHeader; tWITr  
5.F/>?<  
#NQx(C  
for(int i=1;;i++) -~&T0dt~  
{ KdLj1T  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); UI74RP  
//Utility.log(in.readLine()); U9x6\Iy  
sHeader=httpConnection.getHeaderFieldKey(i); ;#E
lJXS  
if(sHeader!=null) R;H>#caJ  
{ ApqNV  
if(sHeader.equals("Content-Length")) vec4R )S  
{ $DhW=(YM_a  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {@ Z%6%'9  
break; *&$2us0%%  
} b2UqN]{  
} JjnWv7W3$  
else k:*vD"  
break; gi<%: [jT  
}
<Eh_  
} WU{9lL=  
catch(IOException e){e.printStackTrace ();} |/~ISB  
catch(Exception e){e.printStackTrace ();} pU[5f5_  
oU)3du   
l'kVi  
Utility.log(nFileLength); YguY5z  
T!QAcO  
{i/7Nx
 
return nFileLength; h[r)HX0hA  
} /e]R0NI  
:p.f zL6X  
.pPtBqp  
//保存下载信息（文件指针位置） 0 1:(QJ  
private void write_nPos() D@`"99z  
{ .*nr3dY  
try{ {lNG:o  
output = new DataOutputStream(new FileOutputStream(tmpFile)); i#(+Kxr]>  
output.writeInt(nStartPos.length); Y(h(Z  
for(int i=0;i<nStartPos.length;i++) 30Udba+{]p  
{ cb%ML1c  
// output.writeLong(nPos); :?H1h8wbCt  
output.writeLong(fileSplitterFetch.nStartPos); gCv[AIE_m  
output.writeLong(fileSplitterFetch.nEndPos); \x=!'  
} >W^)1E,Qh  
output.close(); .'=-@W*  
} \Vl)q>K_h  
catch(IOException e){e.printStackTrace ();} 17yg ~  
catch(Exception e){e.printStackTrace ();} ew*;mQd  
} 5~=wia  
gwN y
]!  
T,5(JP(h3  
//读取保存的下载信息（文件指针位置） NU.YL1  
private void read_nPos() /|,:'W%U  
{ Y!3i3D  
try{ oE$zOS&2  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); :}[D;cx  
int nCount = input.readInt(); 9 N9Q#o$!.  
nStartPos = new long[nCount]; F{FSmUxzK  
nEndPos = new long[nCount]; JwcC9 O  
for(int i=0;i<nStartPos.length;i++) RgLkAHA  
{ JeU1r-i  
nStartPos = input.readLong(); apv"s+  
nEndPos = input.readLong(); E rnGX#@v  
} 4|xQQv  
input.close(); f(.t0{Etq  
} ,Zb_Pu   
catch(IOException e){e.printStackTrace ();} .5+5ca  
catch(Exception e){e.printStackTrace ();} #E@X'jwu  
} 1-?TjR  
0{sYD*gK]  
G[\3)@I  
private void processErrorCode(int nErrorCode) GFgh{'|  
{ q.v_?X<_  
System.err.println("Error Code : " + nErrorCode); ?tf<AZ=+^L  
} |eH*Q%M  
tz_WxOQ0  
9~yp=JOV@  
//停止文件下载 a\Dw*h?b~  
public void siteStop() 0m'tPFQ|  
{ ^LAdN8Cbb  
bStop = true; 4/E>k <MA  
for(int i=0;i<nStartPos.length;i++) -k}&{v  
fileSplitterFetch.splitterStop(); -SKcS#IF  
-|`
E'b81  
vff`Xh>k(  
} m,#Us  
} Y$N D  
//负责部分文件的抓取 nIv/B/>pZ  
**FileSplitterFetch.java F/0x`l  
*/ 5c-'m?k  
package NetFox; *","u;&  
Mx=L lC)  
lv\^@9r  
import java.io.*; ]M/*Beh  
import java.net.*; J3AS"+]  
cT3s{k  
b"&1l2\ A  
public class FileSplitterFetch extends Thread { U$T (R2@  
BH^8!7dkT  
e7JZk6GP#9  
String sURL; //File URL s78V\Vw3  
long nStartPos; //File Snippet Start Position y<n<uZ;  
long nEndPos; //File Snippet End Position ej{7)#  
int nThreadID; //Thread's ID Nj;G%KAP  
boolean bDownOver = false; //Downing is over 7"$9js
2  
boolean bStop = false; //Stop identical 21.N+H'  
FileAccessI fileAccessI = null; //File Access interface za[;d4<}k  
Rb_+C  
?8R  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException G,A;`:/  
{ LJmRa  
this.sURL = sURL; IC@-`S#F  
this.nStartPos = nStart; >y^zagC*  
this.nEndPos = nEnd; ,v>|Ub,  
nThreadID = id; mKhlYVn  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 h!~u^Z.7<  
} &*!) d"  
5=9gH  
vm`\0VGSW  
public void run() E>w|i  
{ eVujur$P  
while(nStartPos < nEndPos && !bStop) t7b\#o  
{ +B-;.]L T  
jGKasI`  
]6TX)1  
try{ J)a^3>  
URL url = new URL(sURL); /_CSRi&
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 7s.vJdA]6  
httpConnection.setRequestProperty("User-Agent","NetFox"); A_<1}8{L  
String sProperty = "bytes="+nStartPos+"-"; Q^\f,E\S  
httpConnection.setRequestProperty("RANGE",sProperty); :H
`Z.>K  
Utility.log(sProperty); h6C:`0o  
Kgu#Mi~  
- ]Mp<Y  
InputStream input = httpConnection.getInputStream(); IL N0/eH  
//logResponseHead(httpConnection); 7P7d[KP<  
%eLf6|1x  
.T }q"  
byte[] b = new byte[1024]; ,?Nc\Q<:  
int nRead; 5sK1rDN  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) :} 9Lb)Yp  
{ TrC :CL  
nStartPos += fileAccessI.write(b,0,nRead); 7T-}oNaJA\  
//if(nThreadID == 1) Wf!<Qot|R#  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d@,3P)?  
} &P3ep[]j  
Y"Y+U`Qt  
Pg/$N5->  
Utility.log("Thread " + nThreadID + " is over!"); zoI0oA  
bDownOver = true; 9Z;"9$+M  
//nPos = fileAccessI.write (b,0,nRead); M8iI e:{ c  
} Aq"<#:  
catch(Exception e){e.printStackTrace ();} 30nR2mB Kt  
} wf=M| #}_  
} 3rQ;}<*M  
g7nqe~`{  
H`X>  
//打印回应的头信息 TWAt
)Q"J  
public void logResponseHead(HttpURLConnection con) n8vteGQ  
{ p:q?8+W-r  
for(int i=1;;i++) 3tIno!|  
{ b~<Tgo_/jf  
String header=con.getHeaderFieldKey(i); 2%zJI"Ic  
if(header!=null) 2v9T&xo=  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); cpg+-Zf%  
Utility.log(header+" : "+con.getHeaderField(header)); @E@5/N6M  
else j,i> 1|J  
break;  {]=oOy1  
} #{o
GmzG!  
} p:9^46N@  
dqo&3^px  
A%
dI8Z,  
public void splitterStop() 
%K|+4ZY3  
{ vaOCH*}h  
bStop = true; Ci?A4q$.  
} bP8O&R  
q%xq\L.  
_|%l) KO  
} " .:b43Z  
_/ Uer}  
[j^c&}0  
/* _ BUD~'Q5  
**FileAccess.java qD/X
%`>Q  
*//文件访问(定位，写) .B|a.-oA4  
package NetFox; M<"H1>q@  
import java.io.*; mbh;oX+  
y
%^TZ[S  
bEc @"^)  
public class FileAccessI implements Serializable{ r%DaBx!x8  
cf ~TVa)M  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 x9{&rldC  
RandomAccessFile oSavedFile; ??tNMr5{[  
long nPos; K$(Li
P  
E A8>{}Z*  
L-v-KO6  
public FileAccessI() throws IOException c (Gl3^  
{ Q!_@Am
"h  
this("",0); >4N=
P0=  
} o$FYCz n  
E5U{.45  
)@OKL0t  
public FileAccessI(String sName,long nPos) throws IOException 'z.: e+Q_  
{ =$t  
oSavedFile = new RandomAccessFile(sName,"rw"); ,V}Vxq3  
this.nPos = nPos; .*>pD/  
oSavedFile.seek(nPos); v)AadtZ0d  
} $IU|zda8  
gcNpA?mC|u  
Sx^4Y\\  
public synchronized int write(byte[] b,int nStart,int nLen) Hg}@2n)/  
{ 1FQ_`wF4  
int n = -1; auKGm:  
try{ oykqCN  
oSavedFile.write(b,nStart,nLen); 37M?m$BL  
n = nLen; jJfV_#'N'  
} hi(uL>\  
catch(IOException e) +,BJ4``*k  
{ f<T"# G$5  
e.printStackTrace (); #MhieG5  
} C)|{7W  
$6 A91|ZSQ  
A_
vf3 *q  
return n; j%y)%4F8  
} yA#-}Y|]b  
> l@o\  
wK[Xm'QTPJ  
} xf?6_=  
R:LThFx  
~wdKO7fs  
/* ?{Gf'Y}y&  
**SiteInfoBean.java H#
+?)<UQ  
*/ (i*;V0  
package NetFox; c8 xZT  
[,1\>z|&  
0,x<@.pW  
public class SiteInfoBean { EN!Q]O|  
:',Q6j(s  
7P2?SW^
 
private String sSiteURL; //Site's URL +UTs2*H/^  
private String sFilePath; //Saved File's Path u3>Dvl@  
private String sFileName; //Saved File's Name s{]2~Z^2od  
private int nSplitter; //Count of Splited Downloading File 1-=zSWmyK  
1*>lYd8_  
DE^@b+6  
public SiteInfoBean() \?X'U:  
{//nSplitter的缺省值为5 ^8#;>+7R  
//default value of nSplitter is 5 D\H)uV`  
this("","","",5); a &89K  
} YdI&OzaroE  
]1XJQW@gF  
H)
${"  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) IO4 8sV }  
{ < x==T4n/  
sSiteURL= sURL; 34$qV{Y%y  
sFilePath = sPath; Lb>UraUvL  
sFileName = sName; $M(ZKS3,j  
this.nSplitter = nSpiltter; R3dCw:\O+Z  
FojsI<  
k^ZcgHHgb  
} nd 5w|83  
!AGjiP$  
E2D}F
@<]  
public String getSSiteURL() h 'F
\9t  
{ ny.YkN2  
return sSiteURL; !VfP#B6.  
} Cy~Pfty  
O\(0{qu  
@%5$x]^  
public void setSSiteURL(String value) @sV6g?{tI  
{ 9z:P#=Q:  
sSiteURL = value; y^SDt3Am  
} V+M=@Pvp9  
#!WD1a?L  
AxOn~fZ!  
public String getSFilePath() hu G]kv3F:  
{ 1gZW~6a}  
return sFilePath; *k]izWsV*  
} e uF@SS  
9? #pqw  
jo-qP4w  
public void setSFilePath(String value) c-2##Pf_8O  
{ K`25G_Y3@  
sFilePath = value; X R =^zp?  
} yE\dv)(<  
>c~Fgs  
lAM"l)Ij  
public String getSFileName() Of*z9YI  
{ ^@&RJa-kb  
return sFileName; 0PK*ULwSN  
} 3r)<:4a u&  
^_cR  
c%|18dV  
public void setSFileName(String value) ;L
Bq!  
{ dz6i~&  
sFileName = value; \.R+|`{tf  
} E_aDkNT  
22|a~"Z  
.!\NM&E  
public int getNSplitter() Vko1{$}t  
{ :d7tzYT ^  
return nSplitter; ;34 m!\N5  
} vB:_|B  
,DHiM-v  
4;*o}E  
public void setNSplitter(int nCount) {hr+ENgV  
{ Wa8?o~0"L  
nSplitter = nCount; @"6dq;"  
} hY?x14m$3  
} o+H;ZGT5H  

{ws:g![  
"v"w ER?  
/* BtyBZ8P;e  
**Utility.java k-v@sb24_  
*/ em87`Hj^lo  
package NetFox; *uLlf'qU]  
i_? S#L]h  
O;NQJ$^bI  
public class Utility { 2VNMz[W'  

v$O%U[e<  
M-Az2x;6  
public Utility() <fJ*{$[p  
{ $_6DvJ0  

=)B@`"  
}NQ{S3JW  
} QT;mCD=O
D  
/A U& X  
//线程睡眠 $6ZO V/0  
public static void sleep(int nSecond) 6S;-fj  
{ f$lf(brQ:  
try{ X676*;:!.  
Thread.sleep(nSecond); -`mHb  
} 8?lp:kM  
catch(Exception e) UqaLTdYG  
{ %n3l
m(-0U  
e.printStackTrace (); (W<n<sl:-  
} p+O2:  
} 6wzTX8  
X]?qns7  
//日志 6$}hb|j  
public static void log(String sMsg) `YDe<@6'  
{ (z}q6Lfa  
System.err.println(sMsg); ~*|0yPFg  
} 26YY1T\B)  
%|l^oC+E  
?jywW$   
public static void log(int sMsg) MYzyg  
{ edt(Zzk@3-  
System.err.println(sMsg); ,cR=W|6cQm  
} 4uW}.7
R'  
} H0Q.; !^  
!BN7 B  
fIo7R-XP  
/* %)7HBj(*J  
**TestMethod.java 'J&&F2O%  
*/ .=WsB@+   
package NetFox; KJ Gh)  
Z:l.{3J$  
\}0J%F1  
public class TestMethod { L{K:XiPn  
c=U1/=R5  
C F2*W).+  
public TestMethod() n
VqFCBB  
{ ///xx/weblogic60b2_win.exe k_rtsN  
try{ ;%r#pv~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); x[Xj[O  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); b(lC7Xm  
SiteFileFetch fileFetch = new SiteFileFetch(bean); \:cr2w'c  
fileFetch.start(); #>m#i1Nu  
} w<?v78sT  
catch(Exception e){e.printStackTrace ();} Hq.ys>_  
mK3U*)A   
;><9R@0  
} 6Q&R,"!$p  
U*G9fpVy  
[vuqH:Ln  
public static void main(String[] args) K)|#FRPM u  
{ 6{rH|Z  
new TestMethod(); $?^#G8J  
} D2$"!7O1H  
} 'Ldlo+*|5  
点击下载更多相关资料