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http断点续传简单实现(java)

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/* x~{W(;`!  
**SiteFileFetch.java % I2JS  
*/ bk a%W@Y%  
package NetFox; 9U=6l]Np  
import java.io.*; 9>`dB  
import java.net.*; }m7$,'C%P  
#CB Kt,  
+Z"[2Dm  
public class SiteFileFetch extends Thread { t)~$p#NS  
H\9ePo\b~  
#YK3Ogb,  
SiteInfoBean siteInfoBean = null; //文件信息Bean m@0> =s~.  
long[] nStartPos; //开始位置 jR@>~t[}o  
long[] nEndPos; //结束位置 ~@[<y1g?nG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \g)?7>M|  
long nFileLength; //文件长度 NX:\iJD)1U  
boolean bFirst = true; //是否第一次取文件 h]&~yuI>  
boolean bStop = false; //停止标志 -9o7a_Z  
File tmpFile; //文件下载的临时信息 yMD0Tj5ZQ  
DataOutputStream output; //输出到文件的输出流 }jdmeD:  
*O)i)["  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) EVA&By6_k  
public SiteFileFetch(SiteInfoBean bean) throws IOException wByTNA7  
{ 6BEDk!  
siteInfoBean = bean; ,^eOwWV  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); HNlW.y"  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); jtE'T}!d  
if(tmpFile.exists ()) bMv[.Z@v(  
{ 4nh0bIN1  
bFirst = false; Z/4bxO=m  
read_nPos(); ^<   
} nY\X!K65  
else 1Y~'U =9  
{ Ol|fdQ  
nStartPos = new long[bean.getNSplitter()]; 9JJ6$cLF  
nEndPos = new long[bean.getNSplitter()]; <54KWC86)J  
} we@*;k@_  
d5R2J:dI  
@3FQMs4  
F"3'~ 6  
} :7(d 6gEL  
%dhrXK5  
wu b7w#  
public void run() Xr88I^F;  
{ HIfi18  
//获得文件长度 -SzCeq(p%5  
//分割文件 X\*H7;k,  
//实例FileSplitterFetch ,_=LV  
//启动FileSplitterFetch线程 ;<xPzf  
//等待子线程返回 7vI ROK~  
try{ ^v:XON<  
if(bFirst) yC4%z) t&R  
{ n0%S: (  
nFileLength = getFileSize(); niYD[Ra\xP  
if(nFileLength == -1) |It{L0=U  
{ <dz_7hR"  
System.err.println("File Length is not known!"); t^%)d7$  
} N4{g[[ T  
else if(nFileLength == -2) ]+ tO  
{ j)juvat  
System.err.println("File is not access!"); O~6AX)|&=  
} u9]M3>  
else vVsaGW   
{ ^W^Y"0y9`  
for(int i=0;i<nStartPos.length;i++) U<'z, Px6  
{ t$R0UprK  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); s9fEx -!y  
} GpR,n2  
for(int i=0;i<nEndPos.length-1;i++) \\d8ulu  
{ )5o6*(Y  
nEndPos = nStartPos[i+1]; n-<`Z NMU  
} T/J1 b-  
nEndPos[nEndPos.length-1] = nFileLength; $%ww$3  
} V gy12dE  
} 4=& d{.E  
4]Gm4zO  
~i>'3j0@k  
//启动子线程 2<V`  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; %0f*OC  
for(int i=0;i<nStartPos.length;i++) W4h]4X  
{ (+u&b< <6N  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), &iy7It  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), M[_Ptqjb  
nStartPos,nEndPos,i); yC!>7@m  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); IQmlmu  
fileSplitterFetch.start(); piIGSC  
} hWbjA[a/  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +hlR  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ?tT89m3_E  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", F0kQ/x  
nEndPos = " + nFileLength); a"k,x-EL(  
// fileSplitterFetch[nPos.length-1].start(); a@?ebCE  
-YipPo"a  
SF[Z]|0gs  
//等待子线程结束 ^6!8)7b  
//int count = 0; E <r;J  
//是否结束while循环 |I.5]r-EK  
boolean breakWhile = false; |(Xxi  
W)Yo-%  
i}))6   
while(!bStop) V:AA{<  
{ &kH7_Lz  
write_nPos(); F5w=tK  
Utility.sleep(500); 2D3mTpw  
breakWhile = true; P1`YbLER5  
wFBSux$  
Imo?)dYK  
for(int i=0;i<nStartPos.length;i++) p\]rxtm  
{ obgO-d9l  
if(!fileSplitterFetch.bDownOver) Jp~[Dm  
{ L|A1bxt  
breakWhile = false; \@_?mL@=  
break; Jd33QL}Hj  
} _IvqZ/6Y(  
} Jb8%A@Z+  
if(breakWhile) >R\!Qk  
break; m`@~ZIa?>B  
#Jfmt~ks '  
+# @2,  
//count++; t & 5s.  
//if(count>4) H.[(`wi!I  
// siteStop(); ZP.~Y;Ch;-  
} U a1Z,~ *  
}&EdA;/o_  
^3Z~RK\}  
System.err.println("文件下载结束!"); c>#3{}X|x%  
} 1Msc:7:L  
catch(Exception e){e.printStackTrace ();} O+~@ S~  
} {ka={7  
m khp@^5  
}y%mG&KSz  
//获得文件长度 Acb %)Y  
public long getFileSize() QEY#U|  
{ 8oJp_sw  
int nFileLength = -1; (i]0IYMXy*  
try{ nTz( {q  
URL url = new URL(siteInfoBean.getSSiteURL()); iDlg>UYd  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P m|S>r  
httpConnection.setRequestProperty("User-Agent","NetFox"); 0-Wv$o[  
!LpFK0rw  
V:1_k"zQ  
int responseCode=httpConnection.getResponseCode(); 5>h# hcL  
if(responseCode>=400) m =MM  
{ ->@iw!5xu  
processErrorCode(responseCode); ov'C0e+o  
return -2; //-2 represent access is error #2qv"ntW  
} @P<Mc )o^  
M`|E)Y  
q>VvXUyK,  
String sHeader; 6W N(Tw  
F2$?[1^f  
%r:Uff@  
for(int i=1;;i++) xx[l#+:c  
{ EA<x$O  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); >]?!9@#IH  
//Utility.log(in.readLine()); >jm^MS=  
sHeader=httpConnection.getHeaderFieldKey(i); C.hRL4+;Zm  
if(sHeader!=null) qmbhx9V   
{ (.9H1aO46|  
if(sHeader.equals("Content-Length")) |`@7G`x  
{ >F;yfv;  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ":01M},RA  
break; 5Fa/Q>N  
} WVh]<?GWXk  
} V(6Ql j7  
else #80r?,q  
break; Qy| 6A@  
} ?xzDz  
} 8"J6(KS  
catch(IOException e){e.printStackTrace ();} =tqChw   
catch(Exception e){e.printStackTrace ();} 0|`iop%(n  
6i*LP(n  
gqACIXR  
Utility.log(nFileLength); XM?C7/^k  
EdS7m,d  
#e$vv!&}  
return nFileLength; $R/@%U)-o  
} 4d $T6b  
n,%/cUl  
4XArpKA  
//保存下载信息(文件指针位置) `:EU~4s\  
private void write_nPos() g42Z*+P6N  
{ v^(J+d_>   
try{ j79$/ Ol  
output = new DataOutputStream(new FileOutputStream(tmpFile)); JS0957K  
output.writeInt(nStartPos.length); QhmOO-Z?  
for(int i=0;i<nStartPos.length;i++) to;cF6X  
{ c$R<j'7  
// output.writeLong(nPos); L ^{C4}x=  
output.writeLong(fileSplitterFetch.nStartPos); -v?)E S  
output.writeLong(fileSplitterFetch.nEndPos); 2B=+p83<  
} MD=!a5'  
output.close(); %1%@L7wP>  
} w!m4  
catch(IOException e){e.printStackTrace ();} \$D41_Wt|  
catch(Exception e){e.printStackTrace ();} j'nrdr6n  
} ? ]hS^&  
km9@*@)  
kaZ_ra;<  
//读取保存的下载信息(文件指针位置) pDG>9P#mO  
private void read_nPos() uZ(,7>0  
{ A=pyaU`aE  
try{ &3bhK5P  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Yjp*T:6  
int nCount = input.readInt(); 'n!kqP  
nStartPos = new long[nCount]; WEk3 4crk  
nEndPos = new long[nCount]; td\'BV  
for(int i=0;i<nStartPos.length;i++) mA0|W#NB  
{ a3[lZPQe  
nStartPos = input.readLong(); ]`_eaW?Ua  
nEndPos = input.readLong(); o9AwW  
} EMMp4KKOx+  
input.close(); ?4MZT5 .  
} r>x>aJ  
catch(IOException e){e.printStackTrace ();} `NARJ9M   
catch(Exception e){e.printStackTrace ();} t Ai?Bjo  
} bKP@-<:]  
$o>6Io|D  
yU< "tgE  
private void processErrorCode(int nErrorCode) s. jcD  
{ n% ={!WD  
System.err.println("Error Code : " + nErrorCode); 1ppU ?#  
} -{s9PZ3~_  
_$BH.I  
"BD$-]  
//停止文件下载 95hdQ<W  
public void siteStop() @8'LI8 \/  
{ UWg+7RL  
bStop = true; QKtVwsz +  
for(int i=0;i<nStartPos.length;i++) :ej`]yK |  
fileSplitterFetch.splitterStop(); pQ9~^  
g%T`6dvT  
2)47$eu  
} 'w~e>$WI  
} nj5Hls  
//负责部分文件的抓取 1n )&%r  
**FileSplitterFetch.java W`` -/  
*/ \s">trXwX  
package NetFox; P~7p~ke  
Jqgo\r%`  
Xe>   
import java.io.*; i@hW" [A  
import java.net.*; j`ybzG^  
rz]M}!>k  
A<<Bm M.%  
public class FileSplitterFetch extends Thread { z2cd1HxN  
^)0b= (.  
YKG}4{T  
String sURL; //File URL k#pNk7;MZ  
long nStartPos; //File Snippet Start Position &)#bdt[  
long nEndPos; //File Snippet End Position S7 WT`2  
int nThreadID; //Thread's ID O t1:z:Pl  
boolean bDownOver = false; //Downing is over (=/}i'  
boolean bStop = false; //Stop identical &VfMv'%x  
FileAccessI fileAccessI = null; //File Access interface MgUjB~)Y  
=%oQIx  
&1$|KbmV4  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException UZb!tO2  
{ ;;lOu~-*$p  
this.sURL = sURL; i :Sih"=  
this.nStartPos = nStart; JWo).  
this.nEndPos = nEnd; u$V8fus0  
nThreadID = id; I2^ Eo5'  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 G "`t$=0  
} y?.l9  
9 `z^'k&  
yjj)+eJ(Q  
public void run() J\c\Ar :  
{ !;h`J:dN  
while(nStartPos < nEndPos && !bStop) /w2jlu}yt  
{ >^ijj`{d  
qjI.Sr70  
7o4B1YD  
try{ uhO-0H  
URL url = new URL(sURL); ]iE) 8X  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~5sH`w~vQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); U t'r^  
String sProperty = "bytes="+nStartPos+"-"; &NB"[Mm:@  
httpConnection.setRequestProperty("RANGE",sProperty); 5;_&C=[  
Utility.log(sProperty); ^U[yk'!Y  
D ~LU3#n  
~;P>}|6Y  
InputStream input = httpConnection.getInputStream(); r"\g6<RP  
//logResponseHead(httpConnection); *e}1KcJ  
Gn} ^BJN  
PWbi`qF)r  
byte[] b = new byte[1024]; )R@M~d-o  
int nRead; [2Ot=t6]  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >nOzz0,  
{ 85 <%L:EC  
nStartPos += fileAccessI.write(b,0,nRead); sTChbks  
//if(nThreadID == 1) tX 3y{W10"  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); `(Ij@8 4  
} H!vX#  
]#t5e>o|  
$mLiEsJ  
Utility.log("Thread " + nThreadID + " is over!"); {H[3[  
bDownOver = true; E!zAUEVQm[  
//nPos = fileAccessI.write (b,0,nRead); F`U YgN  
} $ Ov#^wfA  
catch(Exception e){e.printStackTrace ();} vQhi2J'  
} ^dCSk==  
} ;/|3U7{c  
5B,HJax  
i8H!4l  
//打印回应的头信息 EGIwqci:  
public void logResponseHead(HttpURLConnection con) f+W8Gszi  
{ 9_I#{ ?  
for(int i=1;;i++) 5_~QS  
{ }&:F,q*  
String header=con.getHeaderFieldKey(i); CY i{WV(:  
if(header!=null) }}MZgm~U)  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); @!:_r5R~N  
Utility.log(header+" : "+con.getHeaderField(header)); k:k!4   
else ?QfomTT  
break; y_A?} 'X  
} 95X!{\  
} ;1[Lwnm  
**L3T3$)  
?)V}_%fVv  
public void splitterStop() J0a#QvX!  
{ 'p:L"L}Q?  
bStop = true; h&$,mbEoI  
} jFThW N  
<;.->73E  
ps=+wg?]  
} %zA$+eT  
&6}] v:  
.e8S^lSl  
/* qtLXdSc  
**FileAccess.java gdVajOAu  
*//文件访问(定位,写) wM#BQe3t#  
package NetFox; P2^((c  
import java.io.*; 0nOp'Ky\k  
a{%]X(';  
Up|>)WFw"  
public class FileAccessI implements Serializable{ Jb4A!g5C  
 ;%tu;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 6a\YD{D] _  
RandomAccessFile oSavedFile; z`Cq,Sz/  
long nPos; 6 SosVE>Z  
t4E=  
byUz  
public FileAccessI() throws IOException ;\gsd'i  
{ ' y9yx[P  
this("",0); !j|93*  
} ,J0BG0jB^u  
9BM 8  
SWGD(]}uz  
public FileAccessI(String sName,long nPos) throws IOException =P.m5e<  
{ t%f6P  
oSavedFile = new RandomAccessFile(sName,"rw"); CN"hx-f  
this.nPos = nPos; / NlT[@T  
oSavedFile.seek(nPos);  4[] /  
} 5V{zdS=  
0u'qu2mV  
/\_wDi+#  
public synchronized int write(byte[] b,int nStart,int nLen) dq{wFI)  
{ Aj;F$(su  
int n = -1; D/&^Y'|T  
try{ Wqu][Wa[Z  
oSavedFile.write(b,nStart,nLen); 0H-~-z8Y  
n = nLen; G#pRBA^  
} Z$? Ql@M  
catch(IOException e) a|x1aN 0  
{ 8C{mV^cn~  
e.printStackTrace (); x1}7c9n K  
} :OVre*j  
]OZk+DU:  
BWct0=  
return n; 9p#Laei].  
} 2y&m8_s-p  
@KhDQ0v]5  
{5=Iu\e  
} ByrK|lVM0  
ZgcJxWC<  
UtF8T6PKdW  
/* $`Z-,AJc  
**SiteInfoBean.java DUk&`BSJ  
*/ ^0/FZ)V8  
package NetFox; V #0F2GV<,  
GN4'LU  
"Z&-:1tP{9  
public class SiteInfoBean { @,<@y>m7  
nl)!)t=n  
+h}>UK\  
private String sSiteURL; //Site's URL 8X@p?43  
private String sFilePath; //Saved File's Path }hralef #N  
private String sFileName; //Saved File's Name b3G4cO;t;  
private int nSplitter; //Count of Splited Downloading File G/nSF:rp  
Zxm Mw  
^T[8j/9o^  
public SiteInfoBean() G6C#M-S  
{//nSplitter的缺省值为5 p`jkyi  
//default value of nSplitter is 5 Q2c|sK8  
this("","","",5); (cX;a/BR  
} R^PPgE6!$  
&@O]'  
HJVi:;o  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) .{` :  
{ "lcNjyU\O  
sSiteURL= sURL; B \U9F5  
sFilePath = sPath; YRXXutm  
sFileName = sName; Ak`7f$z  
this.nSplitter = nSpiltter; '~HCYE:5  
G x;U 3iV  
Q k e8BRBn  
} ~C1lbn b  
&_-,Nxsf  
=IQ+9Fl2  
public String getSSiteURL() }Ut*Y*  
{ d NQ?8P-&  
return sSiteURL; eI8rnp( Ia  
} uD=i-IHT  
>h^CC*&'pw  
Mu,}?%  
public void setSSiteURL(String value) AJ_''%$I3:  
{ {:U zW\5l)  
sSiteURL = value; v~f_~v5J!  
} gnjh=anVX1  
J1@X6U!{  
u@j]U|FpY  
public String getSFilePath() kvWP[! j?)  
{ @>Y.s6a  
return sFilePath; \LYB% K}  
} {}r#s>  
OF[y$<jM  
CH!>RRF  
public void setSFilePath(String value) h<)YZ[;x  
{ [$PW {d8|  
sFilePath = value; ,$"*X-1  
} ObK-<kGcB  
[1+ o  
F1m 1%  
public String getSFileName() +m|S7yr'  
{ J7Z`wjX1  
return sFileName; yQAW\0`  
} |;~kHc$W  
*P\$<4l  
ZDMv8BP7  
public void setSFileName(String value) ['<Q402:.  
{ K90wX1&  
sFileName = value; L#t^:%   
} YJBlF2uD  
v[k;R  
R,]J~TfPK  
public int getNSplitter() ,\YlDcl':0  
{ D<V[:~-o  
return nSplitter; ]]sy+$@~  
} <1t.f}}uX  
vy:-a G  
T\ixS-%^  
public void setNSplitter(int nCount) pr\wI?:k  
{ A_h|f5  
nSplitter = nCount; NOC8h\s}(  
} q mJ#cmN  
} 9'$\GN{0  
$#z ` R;  
.|$:%"O&X  
/* 8iv0&91Z  
**Utility.java 5 )A(q\  
*/ }s9eRmJs  
package NetFox; 9i6z  p'  
D8OW|wVE  
(]_smsok  
public class Utility { /nPNHO>U  
B//2R)HS  
nj90`O.K  
public Utility() I{/}pr>  
{ UFE# J  
)9pRT dT  
Gy]ZYo(  
} `G@(Z:]f,t  
b0(bL_,  
//线程睡眠 f9%M:cl  
public static void sleep(int nSecond) QIK;kjr*A3  
{ \!51I./Q/  
try{ 8I>'x f  
Thread.sleep(nSecond); o4.?m6d  
} qsA`\%]H  
catch(Exception e) xYLTz8g=  
{ -XJXl}M.  
e.printStackTrace (); iQT$#"m n  
} {uCX F~v  
} pu"m(9  
_c z$w5`  
//日志 cv=H6j]h |  
public static void log(String sMsg) w/1Os!p  
{ kB! iEoIBA  
System.err.println(sMsg); %2 I >0  
} >h Rq  
*3!#W|#=]N  
.UGbo.e  
public static void log(int sMsg) dzbFUDJ  
{ JS!`eO/8  
System.err.println(sMsg); _{C =d3  
} )N'-A p$g  
} x:? EL)(  
_SQQS67fu"  
Y00hc8<  
/* UhX)?'J  
**TestMethod.java gebDNl\Y2  
*/ F*4zC@;  
package NetFox; nB9(y4  
t_"]n*zk1  
E4cPCQyeH  
public class TestMethod { )JXlPU  
xt zjFfq  
-)%g MD~z1  
public TestMethod() K/l*Saj  
{ ///xx/weblogic60b2_win.exe -Q MO*PY  
try{ =M."^X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Q3'L\_1L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); dr gCr:Gf  
SiteFileFetch fileFetch = new SiteFileFetch(bean); CQns:.`$`  
fileFetch.start(); h|{DIG3  
} PLueH/gC.  
catch(Exception e){e.printStackTrace ();} ,Zva^5  
vo"?a~kY7  
]j+J^g  
} oIv\Xdc81  
iO dk)  
DEQ7u`6  
public static void main(String[] args) {' UK> S  
{ l_i&8*=Px  
new TestMethod(); D16w!Mnz{K  
} r E&}B5PN=  
} v 8B4%1NE  
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