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http断点续传简单实现(java)

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/* PXRkK63  
**SiteFileFetch.java t{ R\\j  
*/ nsM=n}$5x  
package NetFox; iiw\  
import java.io.*; y$Rr,]L  
import java.net.*; VPh0{(O^=  
;Eer  
V8Fp1?E9S  
public class SiteFileFetch extends Thread { {#_CzI.0f  
ye-EJDZN  
U $2"ZyFii  
SiteInfoBean siteInfoBean = null; //文件信息Bean DT Cwf  
long[] nStartPos; //开始位置 \{8?HjJEM  
long[] nEndPos; //结束位置 ]+ KN9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1LK`    
long nFileLength; //文件长度 EDA%qNd]j  
boolean bFirst = true; //是否第一次取文件 S#{jyU9 ]  
boolean bStop = false; //停止标志 b5@sG^  
File tmpFile; //文件下载的临时信息 sYG:\>}ie  
DataOutputStream output; //输出到文件的输出流 )9]DJ!]&Q"  
.S{FEV  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) l 10p'9 n  
public SiteFileFetch(SiteInfoBean bean) throws IOException g5OKhL0u  
{ x%!Ea{ s  
siteInfoBean = bean; n`Y"b&  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 0|J]EsPxu  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); "?X,);5S  
if(tmpFile.exists ()) A5\00O~  
{ X9-WU\?UC  
bFirst = false; x* 9 Xu"?  
read_nPos(); J\@W+/#dF  
} MP3Vo|}3  
else ,l47;@kr  
{ Sf>#Zqj/  
nStartPos = new long[bean.getNSplitter()]; =<;C5kSD  
nEndPos = new long[bean.getNSplitter()]; cEK<CV  
} `B A'a" $  
F{*h~7D-|  
'nMj<:0wlD  
6L!/#d0  
} \2c 3Nsra  
x_+-TC4IXn  
k',#T932x1  
public void run() Ov-Y.+L:  
{ Hh1]\4D,4  
//获得文件长度 ixY[ HDPq  
//分割文件 /=(PMoZu  
//实例FileSplitterFetch TlEd#XQgf&  
//启动FileSplitterFetch线程 ^cnTZzT#Q  
//等待子线程返回 s0To^I  
try{ CiNOGSlDj  
if(bFirst) 2bnYYQ14:  
{  81}JX  
nFileLength = getFileSize(); (B^rW,V[R  
if(nFileLength == -1)  ;H4s[#K  
{ $ o }  
System.err.println("File Length is not known!"); MtD0e@  
} Mp7X+o/  
else if(nFileLength == -2) (k^o[HF  
{ rHa*WA;TE  
System.err.println("File is not access!"); cFZcBiw  
} *8I"7'xh  
else "OO)m](w  
{ jAcrXB*  
for(int i=0;i<nStartPos.length;i++) A`:a T{j  
{ W5Uw=!LdEY  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); =o5|W'>`  
} S0' ACt`  
for(int i=0;i<nEndPos.length-1;i++) S aH':UN  
{ "}x%5/(  
nEndPos = nStartPos[i+1]; 2;w`W58  
} `x]`<kS;  
nEndPos[nEndPos.length-1] = nFileLength; 7C9_;81_Dt  
} /os,s[w  
} } 3}H}  
zMXQfR   
|[Rlg`TQ;*  
//启动子线程 y}U}AUt  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; sR4B/1'E  
for(int i=0;i<nStartPos.length;i++) (2Z k fN  
{ l86gs6>  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), DS1{~_>nFu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ]SmN}Iq1  
nStartPos,nEndPos,i); ictV7)  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `k6ZAOQtX  
fileSplitterFetch.start(); f.Y [2b  
} TjE'X2/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,rS?^"h9  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); I<rT\':9  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )~0TGy|  
nEndPos = " + nFileLength); mKBO<l{S  
// fileSplitterFetch[nPos.length-1].start(); b+CJRB1  
VTa%  
5HaI$>h6  
//等待子线程结束 c;Gf$9?iC  
//int count = 0; S J2l6  
//是否结束while循环 al"=ld(  
boolean breakWhile = false; L++qMRk9  
[jv+Of IZ  
kMx)G]  
while(!bStop) ;pw9+zo ^M  
{ zP&D  
write_nPos(); tv_&PIu]L  
Utility.sleep(500); bXi!_'z$  
breakWhile = true; P~M[i9 V  
1,(WS F  
PX*}.L *x  
for(int i=0;i<nStartPos.length;i++) 1\a.o[g3e  
{ v5\5:b {/  
if(!fileSplitterFetch.bDownOver) V}Ee1C  
{ :,ucJ|  
breakWhile = false; #g/m^8n?s  
break; !z1\ #|>  
} nb.|^O?  
} <aLS4  
if(breakWhile) Q5b9q$L$  
break; =4$ErwI_dm  
%P7 qA  
|\W53,n9  
//count++; r )HZaq  
//if(count>4) /9=r.Vxh  
// siteStop(); oY+p;&H  
} N% ?R(  
_X|prIOb=  
WvZt~x&2  
System.err.println("文件下载结束!"); Z9.0#Jnu  
} :(\JY?+w   
catch(Exception e){e.printStackTrace ();} ?N(<w?Gat  
} G c \^Kg^#  
gyb99c,)  
UiVGOQq  
//获得文件长度 d_Jj&:"l  
public long getFileSize() :dqZM#$d  
{ Gj?$HFa  
int nFileLength = -1; 6?Kl L [~  
try{ inFS99DKx  
URL url = new URL(siteInfoBean.getSSiteURL()); l/,la]!T  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `^] D;RfE  
httpConnection.setRequestProperty("User-Agent","NetFox"); @C<ofg3E  
&)jq3  
\1SC:gN*#  
int responseCode=httpConnection.getResponseCode(); i),bAU!+m  
if(responseCode>=400) 'J$@~P  
{ 9GRQ^E  
processErrorCode(responseCode); zn>+ \  
return -2; //-2 represent access is error wBvVY3VQ^  
} ZS%W/.?  
;{aGEOP'U  
`U=Jbdc l3  
String sHeader; Af\  
Vm[F~2+HX  
1Au+X3   
for(int i=1;;i++) Xo:Mar  
{ 2e-`V5{)b  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); x0b=r!Duu  
//Utility.log(in.readLine()); v$D U q+  
sHeader=httpConnection.getHeaderFieldKey(i); x5CMP%}d  
if(sHeader!=null) ?% [~J  
{ 2n$Wey[  
if(sHeader.equals("Content-Length")) peF)U !`D  
{ 1yZA_x15:  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *`rfD*  
break; uIbAlE  
} ZSs@9ej  
} y%X! l(gQ  
else 5|=J\Lp2I  
break; x9AFN  
} #%2d;V  
} cS'{h  
catch(IOException e){e.printStackTrace ();} zPx R=0|  
catch(Exception e){e.printStackTrace ();} W7Y@]QMX  
B;?)X&n|X  
/y$Fw9R;  
Utility.log(nFileLength); b*.aaOb  
k qL.ZR  
4g"%?xN  
return nFileLength; 8]Tv1Wc  
} ,~=]3qmbR  
eZ+6U`^t  
.>eRX%  
//保存下载信息(文件指针位置) NhCucSU<K  
private void write_nPos() lcm3wJ'w  
{ E*u*LMm  
try{ BvsSrse  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 1f<R,>  
output.writeInt(nStartPos.length); #G.eiqh$a  
for(int i=0;i<nStartPos.length;i++) aopZ-^  
{ +]nIr'V  
// output.writeLong(nPos); MqB@}!  
output.writeLong(fileSplitterFetch.nStartPos); +C8O"  
output.writeLong(fileSplitterFetch.nEndPos); e b} P/  
} *!ng)3#  
output.close(); Ps>:|j+  
} 9OV@z6  
catch(IOException e){e.printStackTrace ();} $L 8>Ha}  
catch(Exception e){e.printStackTrace ();} rD~/]y)t  
} 0cE9O9kE  
 0U@#&pUc  
}L)[>  
//读取保存的下载信息(文件指针位置) &hO-6(^I  
private void read_nPos() ;aV3j/  
{ L FkDb}  
try{ vMB61 |O  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); aZ4?! JW.  
int nCount = input.readInt(); kqm(D#  
nStartPos = new long[nCount]; Gk{ 'U  
nEndPos = new long[nCount]; :Y\ ~[Y  
for(int i=0;i<nStartPos.length;i++) **L&I5Hhm  
{ S )rr  
nStartPos = input.readLong(); 60vmjmXl  
nEndPos = input.readLong(); \1jThJn  
} jkx>o?s)z  
input.close(); jel:oy|_  
} Ig t*8px  
catch(IOException e){e.printStackTrace ();} C[<}eD4bV  
catch(Exception e){e.printStackTrace ();} <@"rI>=  
} %*}rLn"?  
Yr/$92(  
Jgv Mx  
private void processErrorCode(int nErrorCode) 7%i'F=LzT  
{ hqvhnqQk  
System.err.println("Error Code : " + nErrorCode); X7huc*  
} $C;i}q#  
}[;ZZm?  
?E"192 ,z@  
//停止文件下载 9L:wfg}8s  
public void siteStop() 'EiCT l  
{ L@{'J  
bStop = true; qC> tni%  
for(int i=0;i<nStartPos.length;i++) Vo@7G@7K(  
fileSplitterFetch.splitterStop(); U-9Aq  
X|T|iB,vT  
!xfDWbvHV  
} SjB"#E)  
} \jwG*a  
//负责部分文件的抓取 1H-Y3G>jN  
**FileSplitterFetch.java a]u.Uqyx2w  
*/ q4[}b-fF  
package NetFox; UeO/<ml3>J  
{&,p<5o  
j|[rT^b@  
import java.io.*; 9?H$0xZV  
import java.net.*; ; R}>SS'  
^)~Smj^d  
Wp>t\S~N  
public class FileSplitterFetch extends Thread { `FPQOa*%3  
5G}4z>-]F)  
}ouGxs+^[  
String sURL; //File URL {&n- @$?  
long nStartPos; //File Snippet Start Position ~i"=:D  
long nEndPos; //File Snippet End Position F<,pAxl~@  
int nThreadID; //Thread's ID 3p=Xv%xd  
boolean bDownOver = false; //Downing is over E:x@O8F  
boolean bStop = false; //Stop identical ks0Q+YW  
FileAccessI fileAccessI = null; //File Access interface ?Fl}@EA#M  
%=UD~5!G0  
BA c+T  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException KMj\A d  
{ ->b5"{t  
this.sURL = sURL; v`Jt+?I  
this.nStartPos = nStart; wHj 1+W  
this.nEndPos = nEnd; 9 8|sWI3 B  
nThreadID = id; o1ZVEvp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 jg710.v:  
} tTy!o=  
5v)^4( )  
,%TBW,>  
public void run() r >'tE7W9  
{ o}v<~v(  
while(nStartPos < nEndPos && !bStop) ~#sD2b` 0  
{ U3{<+vSR`  
Z< i }XCE  
v0\l~_|H  
try{ {$z54nvw$  
URL url = new URL(sURL); 1%+-}yo<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qS vV |G  
httpConnection.setRequestProperty("User-Agent","NetFox"); :hZM$4  
String sProperty = "bytes="+nStartPos+"-"; m !*F5x  
httpConnection.setRequestProperty("RANGE",sProperty); BYq80Vk%@  
Utility.log(sProperty); mKZzSd)p  
}=/zG!+  
@:}c(j  
InputStream input = httpConnection.getInputStream(); y(J~:"}7)  
//logResponseHead(httpConnection); ^/ "}_bR  
nqo{]fn  
Op%OQ14$  
byte[] b = new byte[1024]; xJCx zJ  
int nRead; tP@NQCo  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) i//H5D3  
{ \ASt&'E  
nStartPos += fileAccessI.write(b,0,nRead); SY +0~5E  
//if(nThreadID == 1) f kZHy|m  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  g{Hgs  
} Me .I>7c  
s(=wG|   
$X#y9<bW  
Utility.log("Thread " + nThreadID + " is over!"); ^X96yj'?  
bDownOver = true; |(.\J`_e  
//nPos = fileAccessI.write (b,0,nRead); wb$uq/|  
} `9^tuR,  
catch(Exception e){e.printStackTrace ();} |{N{VK  
} +K1M&(  
} KR>)Ek  
Iq + N0G<j  
Pf[E..HF*d  
//打印回应的头信息 Ol>q(-ea  
public void logResponseHead(HttpURLConnection con) PFJ$Ia|  
{ axnlI*!  
for(int i=1;;i++) aJ+V]WmA  
{ pp@ Owpb  
String header=con.getHeaderFieldKey(i); V'i-pn2gyu  
if(header!=null) '#+&?6p  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 0vv~G\yM  
Utility.log(header+" : "+con.getHeaderField(header)); }p~2lOI  
else oPKLr31zt  
break; p3M!H2W  
} j9+4},>>CU  
} WQ9e~D"  
fQfn7FaW_\  
(.4lsKN<  
public void splitterStop() Tvx1+0Z%z  
{ wo@ T@Ve~  
bStop = true; OD8 fn  
} aFTWzz  
QF>T)1&J[7  
&*v\t\]  
} &en. m>9,  
O&l4/RtQ\)  
TDH^x1P  
/* ~7 i{~<?  
**FileAccess.java JIySe:p3  
*//文件访问(定位,写) ^ }7O|Y7  
package NetFox; E#J})cPzw  
import java.io.*; f!'i5I]  
UY(T>4H+h  
]}v]j`9m%  
public class FileAccessI implements Serializable{ b}K,wAx  
pl]|yIZ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 hP"2X"kz&  
RandomAccessFile oSavedFile; {:1j>4m 2  
long nPos; BP3Ha8/X  
1wR[nBg*|  
dbby.%  
public FileAccessI() throws IOException  QHNyH  
{ ~[%CUc"  
this("",0); )]P(!hW.  
} ,31 ? Aa  
h1_Z&VJ  
}-oba_  
public FileAccessI(String sName,long nPos) throws IOException \|,| )  
{ yx]9rD1cz  
oSavedFile = new RandomAccessFile(sName,"rw"); P{o)Ir8Tt  
this.nPos = nPos; ^QS`H@+Z  
oSavedFile.seek(nPos);  (Q8!5s  
} G8av5zR  
2{=]Pf  
]E/0iM5  
public synchronized int write(byte[] b,int nStart,int nLen) 1iF=~@Nz_  
{ Pe _O(  
int n = -1; ,jY:@<n  
try{ yT7$6x  
oSavedFile.write(b,nStart,nLen); 'I$FOH   
n = nLen; N68mvBe  
} ng%[yY  
catch(IOException e) p>tkRA?lk  
{ A*OqUq/H`;  
e.printStackTrace (); .iy4 (P4  
} ^+>*Y=fl  
cB uuq  
@ VWED  
return n; w ,j*I7V  
} NxHUOPAJc  
X)3(.L  
JWb +  
} aC,adNub  
p":u]Xgb  
;E.]:Ia~  
/* "6jt$-?  
**SiteInfoBean.java QY;(Ny/(y  
*/ !UoA6C:  
package NetFox; nm5DNpHk  
;I4vPh5Q  
e8vy29\S  
public class SiteInfoBean { KuP#i]Na  
?06gu1z/  
5Y *4a%"  
private String sSiteURL; //Site's URL [^"*I.Z_  
private String sFilePath; //Saved File's Path WGv47i  
private String sFileName; //Saved File's Name ,j_js8r  
private int nSplitter; //Count of Splited Downloading File T~E;@weR  
z x-[@G  
j}uL  
public SiteInfoBean() >?@5>wF  
{//nSplitter的缺省值为5 NW[K/`-CTH  
//default value of nSplitter is 5 0"R>:f}  
this("","","",5); DsMo_m/"1  
} JR] 2Ray  
aF 2vgE\  
/WnCAdDgZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F*KQhH7Gf  
{  FSMM  
sSiteURL= sURL; Ph=NH8  
sFilePath = sPath; l2LQV]l  
sFileName = sName; :Qge1/  
this.nSplitter = nSpiltter; FOG{dio  
x$d[Ovw-  
h?xgOb!4  
} p7|I>8ur.  
d'';0[W)  
X~r9yl>  
public String getSSiteURL() LACrg  
{ o ]*yI[\  
return sSiteURL; x {NBhq(4  
} D)PX|xrn  
E*YmHJ:k  
B=cA$620  
public void setSSiteURL(String value) Ic0Sb7c  
{ /GgID!8  
sSiteURL = value; D)-LZbPa  
} Jt[ug26  
|?88EG@05  
4;YP\{u  
public String getSFilePath() QGpj$ _b  
{ N?qETp-:  
return sFilePath; _x.2&S89  
} *HD(\;i-$  
M`&t=0D  
ZN}`A7  
public void setSFilePath(String value) l!,tssQ  
{ +v B}E  
sFilePath = value; 2'fd4 rE5  
} O!"K'Bm  
 :tZsSK  
d#T5=5 #  
public String getSFileName() J,W $\V]p  
{ $ +WXM$N  
return sFileName; ^&<M""Z  
} s&E,$|80  
}uIQ@f`  
?2"g*Bak  
public void setSFileName(String value) je mb/ :E  
{ 5ngs1ZF@  
sFileName = value; .eN"s'  
} #m U\8M,  
b:S$oE  
9?\cm}^?  
public int getNSplitter() hrKeOwKHU  
{ 8]#FvgX  
return nSplitter; ('7?"npd  
} )x!q;^Js9A  
+<\LY(o  
8[@,i|kgg0  
public void setNSplitter(int nCount) +'m9b7+v  
{ zLl-{Kk  
nSplitter = nCount; ->I.D?p  
} FsqH:I4O  
} 5X^\AW  
X4o#kW  
NV./p`k  
/* (A?>U_@  
**Utility.java YW7w>}aW  
*/ % f;v$rsZ  
package NetFox; HB )+.e  
"[ S[vkI  
x;W!sO@$  
public class Utility { qXtC7uNj$  
cpk\;1&t  
=Z.0-C>W  
public Utility() ?eTZ>o.p/  
{ 7Q!ksp  
[7><^?t V  
diXWm-ZKL  
} #f(a,,Uu'  
"7sv@I_j  
//线程睡眠  (7X  
public static void sleep(int nSecond) QI[WXx p  
{ uT]$R  
try{ c%5P|R~g]p  
Thread.sleep(nSecond); yM 7{v$X0  
} J0Yb_(w  
catch(Exception e) rTR$\ [C  
{ \Hb!<mrp  
e.printStackTrace (); ;I5P<7VW  
} -+){;,  
} {EZR}N  
+\+j/sa  
//日志 NzZ(N z5  
public static void log(String sMsg) p{oz}}  
{ pq0Z<b;2  
System.err.println(sMsg); $x }R2  
} { 5r]G  
/'8%=$2Kw  
/[ m7~B]QE  
public static void log(int sMsg) qD%88c)g  
{ n_{&dVE  
System.err.println(sMsg); J-+mdA  
} Dh^l :q+c  
} 7y^)n<'co  
npeL1zO-$  
O$z"`'&j#  
/* d%}?%VH  
**TestMethod.java $/^Y(0  
*/ 3q4VH q  
package NetFox; 48,*sTRq  
[ DpOI  
G9x l-ag+z  
public class TestMethod { iAe"oXK|  
#TUm&2 +V  
@|\;#$?XW3  
public TestMethod() O4`.ohAZ  
{ ///xx/weblogic60b2_win.exe Zs^zD;zU  
try{ Q=!QCDO(  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); tV4yBe<``  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); dZ" }wKbO  
SiteFileFetch fileFetch = new SiteFileFetch(bean); H.?`90IQ  
fileFetch.start(); 4r;le5@  
} hcU^!mp  
catch(Exception e){e.printStackTrace ();} CXn?~m&K  
EE09 Er %\  
X,@nD@  
} @j\;9>I/  
;|T|*0vY[  
Z^]Oic/0Oa  
public static void main(String[] args) bh" Caz.(t  
{ zk }SEt-  
new TestMethod(); \>su97  
} ,ng/T**@G  
} PU ea`rE?R  
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