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http断点续传简单实现(java)

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/* Z ~9N  
**SiteFileFetch.java |w2AB7EU  
*/ }# x3IE6'  
package NetFox; g)A0PvEu  
import java.io.*; a~7osRmp0  
import java.net.*; ;8T=uCi  
~BZV:Es  
;QQ7vo  
public class SiteFileFetch extends Thread { "V0:Lq  
wKlCx  
sri#L+I  
SiteInfoBean siteInfoBean = null; //文件信息Bean #6jwCEo=V  
long[] nStartPos; //开始位置 CD1=2  
long[] nEndPos; //结束位置 _0["J:s9  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 :"^< aLj  
long nFileLength; //文件长度 PL$F;d  
boolean bFirst = true; //是否第一次取文件 bJF/daC5  
boolean bStop = false; //停止标志 !O6Is'%B  
File tmpFile; //文件下载的临时信息 ls\E%d  
DataOutputStream output; //输出到文件的输出流 1!wEXH(  
}.cmiC  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Oc9>F\]_m  
public SiteFileFetch(SiteInfoBean bean) throws IOException g <4M!gi  
{ u^$Md WP  
siteInfoBean = bean; eKz~viM'  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); nE0~Y2  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !s*''v*  
if(tmpFile.exists ()) 8{fz0H.<?  
{ B 9Q. s  
bFirst = false; zlztF$Bo  
read_nPos(); 7B\(r~f`t  
} |K;Txe_  
else Yb3f]4EH  
{ (+8xUc(w  
nStartPos = new long[bean.getNSplitter()]; @n X2*j*u  
nEndPos = new long[bean.getNSplitter()]; d.j'0w"   
} F]A~~P  
d"6]?  
tW:/R@@  
_L'cyH.cn  
} ;u};& sm  
&9_\E{o%]  
<o7#?AcPu  
public void run() <GgtP55  
{ u?3NBc$~A  
//获得文件长度 AJ` v  
//分割文件 F2`htM@,  
//实例FileSplitterFetch '#i]SU&*  
//启动FileSplitterFetch线程 -0o6*?[Z  
//等待子线程返回 0 ;_wAk  
try{ {dA ~#fW<  
if(bFirst) BH0#Q5  
{ ho]!G498  
nFileLength = getFileSize(); MupW=3.38  
if(nFileLength == -1) Y `7#[g  
{ t-m9n*\j1  
System.err.println("File Length is not known!"); kad;Wa#h  
} Wj j2J8B  
else if(nFileLength == -2) sp Q4m  
{ #O9*$eMw  
System.err.println("File is not access!"); k\c &2T]W  
} +#uNQ`1v  
else )*K<;WI WH  
{ +:]Aqyc\  
for(int i=0;i<nStartPos.length;i++) EPe]-C`  
{ NVc! g  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); -)O kG#J@  
} B.mbKntK)R  
for(int i=0;i<nEndPos.length-1;i++) ]6B mCh  
{ *Qg5Z   
nEndPos = nStartPos[i+1]; ZE8/ m")  
} f;Bfh3  
nEndPos[nEndPos.length-1] = nFileLength; .eabtGO,  
} Q_kT}6#(J=  
} Z0ncN])  
=tc`:!$  
_:g GD8  
//启动子线程 Cj !i)-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; <duBwkiG  
for(int i=0;i<nStartPos.length;i++) Wz-3?EQ  
{ s"=F^#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), !0OD(XT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [CDXCV-z  
nStartPos,nEndPos,i); hX8gV~E=y  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 1t[;`iZ  
fileSplitterFetch.start(); `  -[Bo  
} C^,4`OI  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "37@Zt  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6A$_&?  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", gR;8ht(pd(  
nEndPos = " + nFileLength); " _:iK]  
// fileSplitterFetch[nPos.length-1].start(); +% XhQ  
,_Qe}qFU  
XewXTd #x  
//等待子线程结束 xxoHH#a  
//int count = 0; f OM^V{)T  
//是否结束while循环 "$W|/vD+  
boolean breakWhile = false; f3zfRhkIk  
QtnM(m  
Db#W/8 a8k  
while(!bStop) 4+5OR&kxZ  
{ hJ;f1dZ7}  
write_nPos(); oEenm\ZI  
Utility.sleep(500); Txt%nzIu  
breakWhile = true; )l#%.Z9  
aYaG]&hb  
#a(%(k S  
for(int i=0;i<nStartPos.length;i++) pkXfsi-Nu  
{ #hgmUa  
if(!fileSplitterFetch.bDownOver) H~?*KcZ 0\  
{ cuQ7kECV  
breakWhile = false; ~m?74^ i  
break; ]&C:>  
} FDF3zzP0  
} Ha)3i{OM  
if(breakWhile) "Ju /[#VCJ  
break; GUu\dl9WA'  
$u; >hk  
@V* ju  
//count++; ~aJW"\{  
//if(count>4) h v$uH7Fz  
// siteStop(); Lp:Nw4_  
} r~$}G-g  
5)d,G9  
[$( sUc(%  
System.err.println("文件下载结束!"); 4_Qa=T8  
} t} *l?$`  
catch(Exception e){e.printStackTrace ();} q_<*esZ,  
} yu`KzIU  
gp~yt0AU  
DKy >]Hca  
//获得文件长度 c*x J=Gz6d  
public long getFileSize() KInUe(g<9M  
{ ^&+zA,aL,A  
int nFileLength = -1; g08*}0-k  
try{ Sf  024  
URL url = new URL(siteInfoBean.getSSiteURL()); J3/\<=Qh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); [x;(cISK1  
httpConnection.setRequestProperty("User-Agent","NetFox"); Rk($lW)  
zmrQf/y{R  
O.@g/05C  
int responseCode=httpConnection.getResponseCode(); ,|T*|2Gm  
if(responseCode>=400) (3 IZ  
{ {S5RK-ax  
processErrorCode(responseCode); <|{L[  
return -2; //-2 represent access is error = n+q_.A  
} %`xV'2H  
>_;kTy,  
Nb~,`bu,2  
String sHeader; w^06z,  
\%sPNw=e  
&Ki> h  
for(int i=1;;i++) DMF?5GX  
{ yGb a  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); :3f-9aRC!  
//Utility.log(in.readLine()); S~+O` y^  
sHeader=httpConnection.getHeaderFieldKey(i); !]$V9F{K  
if(sHeader!=null) UWQtvQ f  
{ f{)+-8  
if(sHeader.equals("Content-Length")) +7| [b  
{ /xl4ohL$a  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); E% <w5d.lq  
break; v<L=!-b^  
} ]i-P-9PA4  
} y,MPGW_  
else <RhOjZgyZ  
break; jCU=+b=  
} d{er |$E?  
} B4`2.yRis  
catch(IOException e){e.printStackTrace ();} Oo FgQEr@  
catch(Exception e){e.printStackTrace ();} fuq( 2&^  
"6?lQw e  
>%-Hj6%  
Utility.log(nFileLength); ,"~WkLI~\t  
PeO]lq  
'S =sj}X  
return nFileLength; 1TKEm9j]u  
} hHcJN  
b6 $,Xh  
T!MZ+Ph`F  
//保存下载信息(文件指针位置) dZPW2yf  
private void write_nPos() !n|#|.0m  
{ $z*@2Non  
try{ >BBl 7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); M2}np  
output.writeInt(nStartPos.length); Vwjk[ DOL  
for(int i=0;i<nStartPos.length;i++) \I?w)CE@R  
{ {}V$`L8  
// output.writeLong(nPos); >xT^RYS  
output.writeLong(fileSplitterFetch.nStartPos); DhZ:#mM{  
output.writeLong(fileSplitterFetch.nEndPos); e"]"F{Q  
} &=YSM.G  
output.close(); yH*hL0mO  
} ODm&&W#*  
catch(IOException e){e.printStackTrace ();} G 0hYFc u  
catch(Exception e){e.printStackTrace ();} +a|"{  
} Z+ixRch@-s  
v2d<o[[C  
M)L/d_4ka  
//读取保存的下载信息(文件指针位置) 5?Bc Y ;  
private void read_nPos() ! 0^;;'  
{ fV 3r|Bp  
try{ ^V[/(Lq  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =4eUAeH {w  
int nCount = input.readInt(); >QXzMN}o  
nStartPos = new long[nCount]; _IWxYp  
nEndPos = new long[nCount]; AIb>pL{  
for(int i=0;i<nStartPos.length;i++) =-_)$GOI'  
{ g6WPPpqus  
nStartPos = input.readLong(); X2qv^G,  
nEndPos = input.readLong(); WE0}$P:  
} ?]^zD k@~  
input.close(); W Zq,()h  
} WJfES2N  
catch(IOException e){e.printStackTrace ();} 2UiR~P]%  
catch(Exception e){e.printStackTrace ();} cph~4wCS[U  
} v,{h:  
KF_?'X0=  
f-4.WW2FN  
private void processErrorCode(int nErrorCode) +td<{4oq8  
{ 9e!vA6Fx  
System.err.println("Error Code : " + nErrorCode); -IadHX}]t  
} n@hl2M6.x9  
:}Ok$^5s  
OOokhZd`  
//停止文件下载 /Y,r@D  
public void siteStop() r$ =qQ7^#  
{ zN%97q_  
bStop = true; @D~B{Hg  
for(int i=0;i<nStartPos.length;i++) ,9d9_c.T  
fileSplitterFetch.splitterStop(); &f-hG3/M  
ND5$bq Nu?  
\@K~L4>  
} gw^'{b  
} V>Fesm"aq  
//负责部分文件的抓取 +TH3&H5I_A  
**FileSplitterFetch.java mk%b9Ko<F  
*/ f8=]oa]  
package NetFox; 6W&_2a7*  
?1peF47Z  
zPR8f-Uvw  
import java.io.*; %m eLW&  
import java.net.*; ,X68xk.'  
eCWPhB 6l  
dQD$K|aUp  
public class FileSplitterFetch extends Thread { IxOc':/jY  
)1lu=gc  
]!Oue_-;  
String sURL; //File URL )o{aeV  
long nStartPos; //File Snippet Start Position m2xBS!fm  
long nEndPos; //File Snippet End Position io.]'">  
int nThreadID; //Thread's ID px=]bALU  
boolean bDownOver = false; //Downing is over 2/B)O)#ls  
boolean bStop = false; //Stop identical 1oty*c  
FileAccessI fileAccessI = null; //File Access interface xzm@ v(  
e\F} q)_  
G>w+#{(  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException F}36IM9/:  
{ o5!f#Y  
this.sURL = sURL; ~jN'J+_$  
this.nStartPos = nStart; eh(<m8I  
this.nEndPos = nEnd; sZg6@s=  
nThreadID = id; A_R!uRD8-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ys8Q.oBv_`  
} E7nFb:zlV  
_w!a`w*3  
HbM0TXo  
public void run() l +'F_a  
{  \S4SI  
while(nStartPos < nEndPos && !bStop) BMFF=  
{ dU_;2#3m  
S_ b/DO  
q/PNJ#<  
try{ QA?oJ_}y  
URL url = new URL(sURL); fDh] tua  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); eKG2*CV  
httpConnection.setRequestProperty("User-Agent","NetFox"); Zb_apjg[4  
String sProperty = "bytes="+nStartPos+"-"; =:=/Gz1  
httpConnection.setRequestProperty("RANGE",sProperty); =-#G8L%Q  
Utility.log(sProperty); QR0(,e$Dl  
p?# pT}1  
nlc.u}#  
InputStream input = httpConnection.getInputStream(); -tLO.JK<  
//logResponseHead(httpConnection); c5% 6Y2W0  
C&<~f#lB  
pHC /(6?  
byte[] b = new byte[1024]; 7K;!iX<d  
int nRead; @?k J).  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) #_JYh?  
{ Q@S-f:!  
nStartPos += fileAccessI.write(b,0,nRead); e,0-)?5R  
//if(nThreadID == 1) 3n]79+w@z  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [XR$F@o  
} :TalW~r|  
np9dM  
MYdO jcN  
Utility.log("Thread " + nThreadID + " is over!"); 56}X/u  
bDownOver = true; h8{(KRa6  
//nPos = fileAccessI.write (b,0,nRead); B&0; 4  
} 2C=Q8ayvX  
catch(Exception e){e.printStackTrace ();} 4aUiXyr*2  
} %*}Y6tl'|  
} "ju'UOcS/  
iE].&>w  
F@YKFk+a  
//打印回应的头信息 646JDX[o  
public void logResponseHead(HttpURLConnection con) g)"gw+ZFc  
{ sG7u}r  
for(int i=1;;i++) 12UD19!  
{ m Y,|J\w@  
String header=con.getHeaderFieldKey(i); K.~q+IYP[  
if(header!=null) 3Q^fVn$tk  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); E_T 2z4lw  
Utility.log(header+" : "+con.getHeaderField(header)); ==N{1gO]  
else HD>q(cK_|8  
break; bulS&dAX  
} xc @Ss[  
} =qy@Wvj$  
O`[aU%4b  
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public void splitterStop() 4rg2y]  
{ soRv1)el  
bStop = true; yx38g ca  
} zeb=8 Dg :  
tq1CwzRX  
4T6 {Y  
} IxZb$h[  
V)ig)(CT  
Y f@e=:  
/* L{-LX= G^  
**FileAccess.java baV>N[F&  
*//文件访问(定位,写) q*7<)VwI  
package NetFox; PNs~[  
import java.io.*; =FP0\cQ.  
4GdX/6C.  
').}Nz  
public class FileAccessI implements Serializable{ tBbOY}.VD  
yw-8#y  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 r!1D*v5&:  
RandomAccessFile oSavedFile; i%m"@7.kk  
long nPos; Mj#-j/{x{5  
W !w,f;  
XRx+Dddt;  
public FileAccessI() throws IOException T;TA7{B  
{ @gC=$A#  
this("",0); l e4?jQQ@L  
} +ZMls [  
@mP]*$00  
t_^X$pL  
public FileAccessI(String sName,long nPos) throws IOException Fb22p6r  
{ Hmt^h(*/2  
oSavedFile = new RandomAccessFile(sName,"rw"); [epi#]m  
this.nPos = nPos; afBE{  
oSavedFile.seek(nPos); Ysq'2  
} {9Y+.46S  
?'86d_8  
g[RI.&?  
public synchronized int write(byte[] b,int nStart,int nLen) 4fk8*{Y  
{ y;w x?1)  
int n = -1; ULrr=5&8  
try{ !* Ti}oIo&  
oSavedFile.write(b,nStart,nLen); Q 1d'~e  
n = nLen; '.Ed`?<p  
} -i0(2*<  
catch(IOException e) Un`^jw#_  
{ o8/ ;;*  
e.printStackTrace (); 4;n6I)&.(  
} #} ~qqJ G2  
-}O1dEn.  
L37Y+C//  
return n; {vUN+We  
} 3vhnwDcK  
"k*PA\U  
g VQjL+_W  
} 61puqiGG^  
::Ke ^dp  
{~!q`Dr3?q  
/* @1.QEyXG  
**SiteInfoBean.java ?0? R  
*/ Q_* "SRz  
package NetFox; S5~VD?O,  
-p3Re9  
,@1p$n  
public class SiteInfoBean { A+6 n#  
\drqG&wl  
(py]LBZ  
private String sSiteURL; //Site's URL <N\v)Ug`  
private String sFilePath; //Saved File's Path W;bu2ym&Q  
private String sFileName; //Saved File's Name 3)-/`iy#  
private int nSplitter; //Count of Splited Downloading File 'RRmIx2X  
06$!R/K  
ST\$=  
public SiteInfoBean() u[nyW3MZ  
{//nSplitter的缺省值为5 }cT_qqw(f%  
//default value of nSplitter is 5 @-UL`+  
this("","","",5); .>Ljnk  
} ^Wxad?@  
>:D j\"o  
GpZ c5c  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) WVVJ  
{ f|O{#AC  
sSiteURL= sURL; Y3Vlp/"rB"  
sFilePath = sPath; $)3%U?AP  
sFileName = sName; #fT*]NN  
this.nSplitter = nSpiltter; XsnF~)YW  
0-~\ W(  
X]\ \,  
} :_!8 WB  
^G6RjJxqp8  
vAyFmdJ^  
public String getSSiteURL() CPNL 94x  
{ >3z5ww  
return sSiteURL; B}PIRk@a1  
} 8\{^|y9-  
X]P:CY  
0eK*9S]  
public void setSSiteURL(String value) W 4F\}A  
{ k0T?-iM  
sSiteURL = value; 035rPT7-2-  
} v|U(+O  
ZDbc  
Me 5_4H&Sg  
public String getSFilePath() |SyMngIY  
{ r*Yi1j/  
return sFilePath; 3B1cb[2y  
} ^^5&QSB:'  
8 Y5  
**}h&k&%2  
public void setSFilePath(String value) Mbjvh2z  
{ ) $PDo 7#  
sFilePath = value; FJasS8  
} `w]s;G[  
y@\V +  
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public String getSFileName() 7)s^8+  
{ "~D]E7Q3y  
return sFileName; E9;|'Vy<E  
} (\SA *.)  
N!g9*Z  
tKpmm`2  
public void setSFileName(String value) 9<KAXr#  
{ 1Tu *79A  
sFileName = value; .'Vww  
} S#+h$UVh  
*4V=z#  
\hB5@e4i2  
public int getNSplitter() hiQha5  
{ V7/I>^X  
return nSplitter; Q[nEsYP  
} iezO9`  
gG/!,Q.Qh  
fMOU$0]$<  
public void setNSplitter(int nCount) R~Ne|V2  
{ k1QpKn*  
nSplitter = nCount; fl\ly `_  
} #-bA[eQV  
} TA{\PKA)  
g1jTy7g?  
~Q\3pI. |  
/* 8 XU1 /i7N  
**Utility.java 1Z9qjV%^  
*/ >yULC|'F&~  
package NetFox; 3`k;a1Z#O'  
{~F4WjHJp  
B[KJR?>  
public class Utility { aoXb22]{  
B'fb^n<  
l,kUhZ@W  
public Utility() 5O\*h;U 6  
{ 3g >B"t  
a[ex[TRKe  
_'(,  
} uuQ(&  
o93`|yWl  
//线程睡眠 cJrmm2.0kD  
public static void sleep(int nSecond)  -4cXRv]  
{ hRCed4qA  
try{ /Z$&pqs!  
Thread.sleep(nSecond); >/8yGBD  
} dxmE3*b`  
catch(Exception e) !_"fP:T>  
{ Y*UA, <-  
e.printStackTrace (); Vv ?-"\Z>  
} >k'c' 7/  
} `DC2gJKk%  
l g-X:Z.  
//日志 {DR`;ea])1  
public static void log(String sMsg) ndkti5L,   
{ Cvf[/C+  
System.err.println(sMsg); B#M5}QT|2  
} Rp5#clsy  
|]c8jG\h  
DK$s&zf  
public static void log(int sMsg) $f zaPD4.  
{ f\jLqZY  
System.err.println(sMsg); e:5bzk!~  
} xftBSdVE  
} mVy|{Oh  
}b-g*dn]5  
QnJZr:4b  
/* uH(f$A  
**TestMethod.java s{$(*_  
*/ D ^x-^6^  
package NetFox; 8@tPm$  
](s'L8 (x  
6*3.SGUY  
public class TestMethod { PBp^|t]E>  
q,+yqrt  
eN^qG 42  
public TestMethod() 43@{JK9G  
{ ///xx/weblogic60b2_win.exe ;S>])5<  
try{ (Kv#m 3~  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); m8o(J\]  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); | y2w9n0D  
SiteFileFetch fileFetch = new SiteFileFetch(bean); D/Mi^5H)  
fileFetch.start(); sPR1?:0:  
} MP>dW nl  
catch(Exception e){e.printStackTrace ();} `-p:vq`  
OEkN(wF  
fe9LEM8j  
} [Ki0b^  
-&-Ma,M?  
apu4DAy&8  
public static void main(String[] args) o/+13C  
{ SF>c\eTtx  
new TestMethod(); c5u@pvSP  
} cj1cZ-  
} ekWePL;rR2  
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