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http断点续传简单实现(java)

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/* w#-J ?/m  
**SiteFileFetch.java CC,f*I  
*/ { /u}  
package NetFox; #8{U0 7]"  
import java.io.*; `]T# uP<u  
import java.net.*; Oh&k{DWE$  
~_XK<}SK  
NKyKsu  
public class SiteFileFetch extends Thread { T09'qB  
%}`zq8Q;  
I1Jhvyd?$  
SiteInfoBean siteInfoBean = null; //文件信息Bean ]cKxYX)J  
long[] nStartPos; //开始位置 N4L#$\M  
long[] nEndPos; //结束位置 ]YF_c,Q  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 X5Fi , /H  
long nFileLength; //文件长度 }Dc7'GZ  
boolean bFirst = true; //是否第一次取文件  mS]&  
boolean bStop = false; //停止标志 gfPR3%EXs  
File tmpFile; //文件下载的临时信息 cYeC7l "  
DataOutputStream output; //输出到文件的输出流 CGp7 Tx#  
}%}yOLo:  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) xG7/[ jG  
public SiteFileFetch(SiteInfoBean bean) throws IOException kGkfLY6B  
{ .7`c(9<  
siteInfoBean = bean; q+J;^u"E  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); |ctcY*+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); U;q GUqI  
if(tmpFile.exists ()) />13?o#  
{ C25EIIdRb  
bFirst = false; r9vO(m~  
read_nPos(); "<Q,|Md  
} 7jzd I!  
else Tw]].|^f-  
{ p* Q *}V  
nStartPos = new long[bean.getNSplitter()]; aS3Fvk0R{h  
nEndPos = new long[bean.getNSplitter()]; ` JZ`j7f  
} IwZe2$f  
<fm<UO,%  
= ;z42oS  
1(`UzC=R|  
} Pe`eF(J  
M\!z='Fi  
ibqJ'@{=e  
public void run() 1$toowb"Zy  
{ $%"?0S  
//获得文件长度 2t3DQ  
//分割文件 (kFg2kG  
//实例FileSplitterFetch {+N7o7  
//启动FileSplitterFetch线程 WW[Gne  
//等待子线程返回 1R"?X'w  
try{ >J['so2Bf  
if(bFirst) t \;,$i  
{ ~}@cSv'(1  
nFileLength = getFileSize(); ^)i1b:4  
if(nFileLength == -1) B4kJ 7Pdny  
{ tvEf-z  
System.err.println("File Length is not known!"); Wu|ANc  
} 6b7SA ,  
else if(nFileLength == -2) KwxO%/-}S  
{ AD0pmD  
System.err.println("File is not access!"); (d ?sFwOt\  
} |<Rf^"T  
else ]dU/;8/%  
{ uk<JV*R=  
for(int i=0;i<nStartPos.length;i++) _I<LB0kgf.  
{ Ef"M e(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); a`E1rK'  
} o"M h wh  
for(int i=0;i<nEndPos.length-1;i++) ? f>pKe  
{ +/|t8zFWs  
nEndPos = nStartPos[i+1]; fKkH [  
} 4lsg%b6_%,  
nEndPos[nEndPos.length-1] = nFileLength; >sl#2,br  
} p`mNy o'  
} 7>$&CWI  
P;DGs]PF  
96]!*}  
//启动子线程 Z+M* z;  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; N~0~1 WQn  
for(int i=0;i<nStartPos.length;i++) yK"T5^o  
{ "CcdwWM  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >Ndck2@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #cdrobJ  
nStartPos,nEndPos,i); ~;uc@GGo  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); m2h@*  
fileSplitterFetch.start(); *%;+3SV  
} RwyRPc _  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l:$i}.C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); TOC2[m c'  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ~&\}qz3  
nEndPos = " + nFileLength); U,e'vS{  
// fileSplitterFetch[nPos.length-1].start(); H\!p%Y  
i?0+f }5<p  
`%oJa`  
//等待子线程结束 4k4 d%  
//int count = 0; ~+OAAkJ9  
//是否结束while循环 l Taw6;  
boolean breakWhile = false; [ :*Jn}  
8AgKK=C =  
kD.KZV  
while(!bStop) jSc!"Trl]  
{ bxR6@  
write_nPos(); BfOQ/k))  
Utility.sleep(500); NuQ l  
breakWhile = true; M`u&-6  
T\3a T  
Tc.k0n%W:b  
for(int i=0;i<nStartPos.length;i++) BK;Gh0mp  
{ {.mP e|  
if(!fileSplitterFetch.bDownOver) i0/RvrLc  
{ Pua| Z x  
breakWhile = false; {>rGe#Vu  
break; 6G0Y,B7&  
} {$H-7-O$  
} mA2L~=v#  
if(breakWhile) OJ!=xTU%h  
break; r)xkpa5  
+$y%H  
Tt\h#E  
//count++; SSo7 U  
//if(count>4) vv0+F6 @  
// siteStop(); Nt'6Y;m!  
} ,C97|6rC  
rO3.%B}  
|0N6]%r  
System.err.println("文件下载结束!"); MFzJ 8^.1R  
} b;k3B7<  
catch(Exception e){e.printStackTrace ();} R.'-jvO  
} :plN<8  
4Fs5@@>X  
RM|2PG1m  
//获得文件长度 l>){cI/D#  
public long getFileSize() '^10sf`"  
{ YDxEWK<  
int nFileLength = -1; 1r?hRJ:'  
try{ 0+dc  
URL url = new URL(siteInfoBean.getSSiteURL()); u(W+hdTap=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); wY'w'%A?  
httpConnection.setRequestProperty("User-Agent","NetFox"); ?_V&~?r   
1XXuFa&  
uw>O|&!  
int responseCode=httpConnection.getResponseCode(); [Zxv&$SQ  
if(responseCode>=400) 'L$}!H1y  
{ o!@}&DE|*L  
processErrorCode(responseCode); (<KFA,  
return -2; //-2 represent access is error Wb{0UkApJ  
} {a9( Qi  
' Ih f|;r  
z&KrG  
String sHeader; JG/Pc1aK  
"&Rt&S  
pB5#Ho>S  
for(int i=1;;i++) rHaj~s 4  
{ )sZJH9[K  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ! %X#;{  
//Utility.log(in.readLine()); :tf'Gw6v  
sHeader=httpConnection.getHeaderFieldKey(i); 6m$lK%P{1  
if(sHeader!=null) hH(w O\s  
{ U]AJWC6  
if(sHeader.equals("Content-Length")) .$"13"  
{ q"9 2][}  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); cKED RX3  
break; h"3Mj*s  
} N5d)&a 7?  
} -\[H>)z]RB  
else Kg6[  
break; e%_J O7  
} OaeX:r+&Q  
} AEd]nVV Q  
catch(IOException e){e.printStackTrace ();} *hvC0U@3  
catch(Exception e){e.printStackTrace ();} F?+\J =LT  
i@m@]-2  
H ]z83:Z  
Utility.log(nFileLength); "K c/Cs2[  
Ygq;jX  
q,m+W='  
return nFileLength; lx\9Y8  
} q5xF~SQGw2  
Us2IeR  
h<<uef9  
//保存下载信息(文件指针位置) `F`{s`E)  
private void write_nPos() .L@gq/x)  
{ #1De#uZ  
try{ giYlLJA*}  
output = new DataOutputStream(new FileOutputStream(tmpFile)); r t0_[i  
output.writeInt(nStartPos.length); 8AQ__&nT  
for(int i=0;i<nStartPos.length;i++) wQ9?Z.-$  
{ nq5qUErew  
// output.writeLong(nPos); 6^e}^~|  
output.writeLong(fileSplitterFetch.nStartPos); 10d.&vNw  
output.writeLong(fileSplitterFetch.nEndPos); IhjZ{oV/@  
} XY^]nm-{I  
output.close();  35%\"Y?  
} 0fzHEL  
catch(IOException e){e.printStackTrace ();} y|/[;  
catch(Exception e){e.printStackTrace ();} aqEmF  
} {/}%[cY =  
D/YMovH%  
i_e%HG  
//读取保存的下载信息(文件指针位置) Dv"HFQuF  
private void read_nPos() Marx=cNj  
{ UQ#t &  
try{ GIZw/L7Yb  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ge7Uety  
int nCount = input.readInt(); 9? y&/D5O  
nStartPos = new long[nCount]; cq0-D d9^&  
nEndPos = new long[nCount]; H~ E<ek'~  
for(int i=0;i<nStartPos.length;i++) %<0'xJ%%Q  
{ [\3W_jR  
nStartPos = input.readLong(); |Kb m74Z%  
nEndPos = input.readLong(); FBxg^g%PB@  
} MfZamu5+F  
input.close(); $p|Im,  
} ^Na3VP  
catch(IOException e){e.printStackTrace ();} M}e}3w  
catch(Exception e){e.printStackTrace ();} '*B%&QC-  
} <?>tjCg'  
o~7D=d?R  
Tq?7-_MLC$  
private void processErrorCode(int nErrorCode) 5=#2@qp  
{ uJ`:@Z^J  
System.err.println("Error Code : " + nErrorCode); xLSf /8e  
} 4sq](! A  
Ihp Ea,v)  
#&X5Di[A  
//停止文件下载 iNr&;  
public void siteStop() ,N1pww?  
{ GkpYf~\Q  
bStop = true; n^|SN9 _r  
for(int i=0;i<nStartPos.length;i++) l >~Rzw  
fileSplitterFetch.splitterStop(); =o4gW`\z  
\%&):OD1  
D"gv:RojD  
} C8W_f( i~  
} OS-k_l L  
//负责部分文件的抓取 f0879(,i  
**FileSplitterFetch.java U(gYx@   
*/ (mplo|>  
package NetFox; ~O~iP8T  
: { iK 5  
zZ,"HY=jN  
import java.io.*; ++n_$Qug  
import java.net.*; xR8y"CpE  
~ mzX1[  
10Q!-K),p  
public class FileSplitterFetch extends Thread { uFA}w:Fm  
>0_{80bdO  
Oyb0t|do+  
String sURL; //File URL +|Izjx]ZV  
long nStartPos; //File Snippet Start Position `A9fanh  
long nEndPos; //File Snippet End Position *{,}pK2*  
int nThreadID; //Thread's ID X .sOZb?$  
boolean bDownOver = false; //Downing is over g&{CEfw&  
boolean bStop = false; //Stop identical SAiaC _  
FileAccessI fileAccessI = null; //File Access interface k[)/,1  
AZf69z  
r KYQ 8T  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException &@FufpPw/  
{ lL'Bop@  
this.sURL = sURL; qI>,PX  
this.nStartPos = nStart; yuC|_nL  
this.nEndPos = nEnd; &dPUd ~&EL  
nThreadID = id; Yxy!&hPLv:  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9oIfSr,y  
} Sk:x.oOZ  
:|8!w  
Apj[z2nr  
public void run() [nG[ x|;|  
{ ?9%$g?3Z  
while(nStartPos < nEndPos && !bStop) Tq SjL{l%  
{ X#Ob^E%J  
v,Zoy|Lu  
[kTckZv  
try{ nch#DE8 2  
URL url = new URL(sURL); f:t j   
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 6q8PLyIp  
httpConnection.setRequestProperty("User-Agent","NetFox"); r9*6=*J|  
String sProperty = "bytes="+nStartPos+"-"; 65nK1W`i  
httpConnection.setRequestProperty("RANGE",sProperty); g6+5uvpd  
Utility.log(sProperty); E62_k 0q  
Ls+vWfF=#  
ej7L-~lxQ  
InputStream input = httpConnection.getInputStream(); 9R">l5u  
//logResponseHead(httpConnection); 4 L 5$=V  
2a;[2':  
Z?d][zGw  
byte[] b = new byte[1024]; c[T@lz(!  
int nRead; cltx(C>   
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) qA[cF$CIl)  
{ EG|_YW7  
nStartPos += fileAccessI.write(b,0,nRead); Yg}b%u,Q  
//if(nThreadID == 1) o^'QGs "  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); $d,/(*Y#-  
} pFV~1W:  
uH(M@7"6_!  
|Qb@.  
Utility.log("Thread " + nThreadID + " is over!"); xj9xUun  
bDownOver = true; *K& $9fah  
//nPos = fileAccessI.write (b,0,nRead); F(ZczwvR  
} dWu;F^  
catch(Exception e){e.printStackTrace ();} Lxv6\3I+  
} {;m|\652B  
} of GoaH*h  
52NI{"  
J qmL|S)  
//打印回应的头信息 ggrkj0  
public void logResponseHead(HttpURLConnection con) $e{[fm x  
{ 7G7"Zule*j  
for(int i=1;;i++) pe>?m^gz[  
{ s}yN_D+V  
String header=con.getHeaderFieldKey(i); TA8  
if(header!=null) A`Rs n\  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); F\v~2/J5v  
Utility.log(header+" : "+con.getHeaderField(header)); So75h*e  
else R,BINp  
break; h(GSM'v  
} ,b5vnW\  
} 6'x3g2C/  
g3yZi7b5FU  
Gm3`/!r  
public void splitterStop() B#}EYY  
{ mxu!$wx  
bStop = true; uHRxV"@}[1  
} "c?31$6  
xn@oNKD0  
g>#}(u!PH  
} | +uc;[`  
th<>%e}5c  
Oqt{ uTI~  
/* d(@ ov^e-  
**FileAccess.java yW\kmv.O  
*//文件访问(定位,写) _3NH"o d  
package NetFox; 8H T3C\$s  
import java.io.*; +F%tBUY{<  
Ct zW do.  
3xKgj5M  
public class FileAccessI implements Serializable{ [0]J 2  
'i:lV'  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 86!$<!I  
RandomAccessFile oSavedFile; $ER9u2  
long nPos; F-M)6&T  
'H4?V  
B2KBJ4rI[1  
public FileAccessI() throws IOException FFe{=H,=  
{  p: eaZ  
this("",0); B/^o$i  
} H0yM`7[y  
e 'F:LMX  
sY?wQ:  
public FileAccessI(String sName,long nPos) throws IOException rx@i .+  
{ !, rF(pz  
oSavedFile = new RandomAccessFile(sName,"rw"); D~|q^Ms,%  
this.nPos = nPos; U.b|3E/^  
oSavedFile.seek(nPos); (<@`MPI\@  
} iel@"E 4  
9 '(m"c_  
"DH>4Q] d  
public synchronized int write(byte[] b,int nStart,int nLen) U!K#g_}  
{ QUfF>,[sv  
int n = -1; W7@Vma`  
try{ %`\Qtsape  
oSavedFile.write(b,nStart,nLen); # JY>  
n = nLen; "3|OB, <;:  
} -j:yEZ4Oy  
catch(IOException e) GU9p'E  
{ .2_xTt   
e.printStackTrace (); m(EV C}Y  
} :S7[<SwL  
57]La^#  
tA'5ufj*:  
return n; .I$+ E  
} lz1cLl m  
 -)KNsW  
opu)9]`z  
} Snp(&TD<<  
t]iKU@3  
%K7;ePu  
/* Z!jJ93A"  
**SiteInfoBean.java Ke]'RfO\  
*/ eb6y-TwY  
package NetFox; {ot6ssT=D  
=<zlg~i  
"(kiMo g-  
public class SiteInfoBean { E9t8SclV  
"Vp:Sq9y  
l8_RA  
private String sSiteURL; //Site's URL fA[T5<66  
private String sFilePath; //Saved File's Path :Z_abKt  
private String sFileName; //Saved File's Name Ir*{IVvej  
private int nSplitter; //Count of Splited Downloading File +qqCk  
"{3|(Qs  
PI,2b(`h_  
public SiteInfoBean() r>PKl'IbE  
{//nSplitter的缺省值为5 )KkV<$  
//default value of nSplitter is 5 LfK/wSvWw  
this("","","",5); SJi;_bVf  
} 8]O#L}"  
)nK+`{;@!  
,9ew75Jl  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) E @Rb+8},"  
{ U!RIeC  
sSiteURL= sURL; a5d_= :S ;  
sFilePath = sPath; TV0Y{x*~iH  
sFileName = sName; F[F  NtZ  
this.nSplitter = nSpiltter; 0;*[}M]Z  
/q7$"wP  
>?G!>kw  
} ljz=u;O)  
EU'rdG*t/R  
g2rH"3sC  
public String getSSiteURL() :O?3lj)  
{ 6Bexwf<u  
return sSiteURL; \yLFV9P}EL  
} 7uF @Xh  
w !<-e>  
knb0_nA  
public void setSSiteURL(String value) 9(_n8br1  
{ 9#~jlq(  
sSiteURL = value; Y`6<:8[?  
} Gc5mR9pV   
g?Rq .py]!  
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public String getSFilePath() h gwS_L  
{ <'A-9y]-v  
return sFilePath; +Mn(s36f2  
} D`.\c#;cN  
qw)Ou]L=  
$"}*#<Z  
public void setSFilePath(String value) IF<T{/MA  
{ |%3>i"Y@AK  
sFilePath = value; 4$ah~E>,t  
} LfCgvq6/pO  
&g0r#K  
7qWa>fX  
public String getSFileName() /#L4ec-'  
{ - ku8n%u  
return sFileName; yZNg[KH  
} o"A?Aq  
Fta=yH }  
o>m*e7l,  
public void setSFileName(String value) U9 Q[K`  
{ *7#5pT~  
sFileName = value; &XXr5ne~C  
} L&]{GNw  
Imyw-8/;  
8|+@A1)&4  
public int getNSplitter() LA(/UA3Izd  
{ kK0zb{  
return nSplitter; 9'|_1Q.b^  
} J%!vhQ  
9J<vkxG9`  
jxYze/I  
public void setNSplitter(int nCount) 1,we: rwX  
{ cA| n*A-j<  
nSplitter = nCount; 3#\C!T0y  
} c{x:'@%/s'  
} ld5+/"$  
gh `_{l  
ofgNL .u  
/* Y 7?q `  
**Utility.java 8k.#4}fP  
*/ "tDB[?  
package NetFox; r $YEq5  
N%=,S?b  
9PaV*S(\TR  
public class Utility { ldRq:M5z  
V~Jt  
Tq6\oIBkV  
public Utility() e#WASHZN  
{ OL@$RTh  
{"rL3Lk  
gnf4H V~  
} U0N6\+  
;:Tb_4Hr  
//线程睡眠 8\PI1U  
public static void sleep(int nSecond) b/E3Kse?  
{ *h pS/g/3\  
try{ R(f%*S4  
Thread.sleep(nSecond); ndk~(ex|j  
} wawJZ+V  
catch(Exception e) lt\Bm<"z!1  
{ 5)->.*G*  
e.printStackTrace (); X8~?uroq  
} 3 [O+wVv  
} f/m0,EERk  
uw@-.N^  
//日志 fEGnI\  
public static void log(String sMsg) Tv|i CYB?  
{ {T0Au{88H  
System.err.println(sMsg); lj+&3<E  
} 'HL.W](  
$wl_  
)t2eg1a:  
public static void log(int sMsg) c;n\HYk  
{ Lg-!,Y   
System.err.println(sMsg); Q*e\I8R}  
} dkQP.Tj$i  
} xlc2,L;i  
O6">Io5  
X2YBZA  
/* Ak3V< =gx  
**TestMethod.java  Qr-,J_  
*/ crgVedx~}  
package NetFox; UH((d*HX4  
i nk !>Z  
dChMjaix  
public class TestMethod { B& 5Md.h  
u!t<2`:h  
JC/nHM  
public TestMethod() ih : XC  
{ ///xx/weblogic60b2_win.exe R\x3'([A5  
try{ #f_.  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 02YmV%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); XXXQAY-,C  
SiteFileFetch fileFetch = new SiteFileFetch(bean); vu:] [2"0  
fileFetch.start(); m.lzkS]P  
} "}S6a?]V  
catch(Exception e){e.printStackTrace ();} !';;q  
( yB]$  
Qn;,OB k  
} ghTue*A  
O]oH}#5b  
N]F}Z#h  
public static void main(String[] args) ku#WQL  
{ M5N #xgR  
new TestMethod(); m@",Zr `f=  
} HzsQ`M4cA  
} gIKQip<  
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