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http断点续传简单实现(java)

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/* -:m;ePK  
**SiteFileFetch.java m:/@DZ  
*/ H|T:_*5  
package NetFox; dW<.  
import java.io.*; Q<zL;AJ  
import java.net.*; $}l0Nh'Eu  
! 2"zz/N{  
b ,7:=-D  
public class SiteFileFetch extends Thread { N{iBVl  
p*W4^2(d  
5JDqSz{  
SiteInfoBean siteInfoBean = null; //文件信息Bean {gl-tRC3  
long[] nStartPos; //开始位置 ][:6En}  
long[] nEndPos; //结束位置 J$&!Y[0  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]1%H.pF  
long nFileLength; //文件长度 }f^r@3Cb3  
boolean bFirst = true; //是否第一次取文件 `8\pihww  
boolean bStop = false; //停止标志 QY-P!JD  
File tmpFile; //文件下载的临时信息 p{!aRB%  
DataOutputStream output; //输出到文件的输出流 NaG1j+LN  
(iGk]Rtzt  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) v*QobI  
public SiteFileFetch(SiteInfoBean bean) throws IOException G-Z_pGer^  
{ 1QE-[|  
siteInfoBean = bean; l},*^Sn<5  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); dnNC = siY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d#I'9O0&  
if(tmpFile.exists ()) k$}XZ,Q  
{ zrU0YHmt  
bFirst = false; kJ>l, AD/  
read_nPos(); s[h'W~  
} -n!.PsGO>  
else Pp:(PoH  
{ sL~TV([6/  
nStartPos = new long[bean.getNSplitter()]; f`p`c*  
nEndPos = new long[bean.getNSplitter()]; FM0)/6I'x  
} /`D]m?  
u q:>g  
>t'/(y  
]0xbvJ8oK  
} z >vzXM  
Ws4aCH1  
r3hj GcpaX  
public void run() Ne@Iv)g?  
{ gx4`pH;B\  
//获得文件长度 tn6\0_5n  
//分割文件 kxhvy,t  
//实例FileSplitterFetch 0^]E-Zf  
//启动FileSplitterFetch线程  ,L\OhT  
//等待子线程返回 7&:gvhw   
try{ JE9|;A  
if(bFirst) vC$[Zm  
{ QZ"Lh  
nFileLength = getFileSize(); s8{3~Hv  
if(nFileLength == -1) +G? 4Wc1  
{ -#Yg B5  
System.err.println("File Length is not known!"); 9O?.0L  
} /^DDU!=(<  
else if(nFileLength == -2) Vg\EAs>f  
{ M=x/PrY"R  
System.err.println("File is not access!"); f 7y1V(t  
} ^;c!)0Q<Z  
else k:Uyez  
{ p44d&9  
for(int i=0;i<nStartPos.length;i++) 6fY(u7m|p  
{ n+rAbn5o$  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); g*b%  
} T5-50nU,~  
for(int i=0;i<nEndPos.length-1;i++) C z4"[C`;  
{ EfcoJgX  
nEndPos = nStartPos[i+1]; IJs*zzR  
} PsEm(.z  
nEndPos[nEndPos.length-1] = nFileLength; ! 0fpD'f!n  
} cA`R~o"  
} WA8Qt\Q  
(".`#909  
/+"BU-aQk  
//启动子线程 HpSgGhL'J&  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]b.@i&M  
for(int i=0;i<nStartPos.length;i++) IpoZ6DB$  
{ |Ag~k? QC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 7sC$hm]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), O=MO M  
nStartPos,nEndPos,i); be$wG O=Ts  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); >VE,/?71@  
fileSplitterFetch.start(); L<J';#BD  
} ]H[RY&GY  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Zu_m$Mx  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Dvo.yn|kB  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", P_z3TK  
nEndPos = " + nFileLength); 1V+a;-?  
// fileSplitterFetch[nPos.length-1].start(); v~?d7p {  
z\oq b) a  
tcwE.>5O  
//等待子线程结束 %^p1ax  
//int count = 0; 9|D!&=8   
//是否结束while循环 n9050&_S  
boolean breakWhile = false; }7IS:"tu  
j7xoe9;TxI  
H"WkyvqXb  
while(!bStop) 82YTd(yB  
{ /$! / F@^  
write_nPos(); 6sRn_y  
Utility.sleep(500); 0J7[n*~  
breakWhile = true; .2C}8GGC'  
Fm`hFBKW  
+%7yJmMw  
for(int i=0;i<nStartPos.length;i++) pOyM/L   
{ a"b9h{h@  
if(!fileSplitterFetch.bDownOver) ot;j6eAH~E  
{ F6}Pwz[c  
breakWhile = false; DFwkd/3"  
break; ,1Suq\ L  
} c;&m}ImLe.  
} q<@f3[A  
if(breakWhile) \"V7O'S)&  
break; G+=eu K2]  
kmi[u8iXD_  
?#<Fxme  
//count++; w_ kHy_)  
//if(count>4) IwZn%>1N  
// siteStop(); {e/12q  
} n (C*LK  
]-bA{@tP.  
k*J}/HO  
System.err.println("文件下载结束!"); >e/;  
} Cj _Q9/  
catch(Exception e){e.printStackTrace ();} N~;=*)_VH  
} ua0`&,a3I  
WQ\'z?P  
- A x$Y  
//获得文件长度 SJ6lI66OX  
public long getFileSize() U8c0N<j  
{ _.' j'j%  
int nFileLength = -1; ?uc=(J+6  
try{ hvtg_w6K  
URL url = new URL(siteInfoBean.getSSiteURL()); 6|V713\  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 1/j J;}  
httpConnection.setRequestProperty("User-Agent","NetFox"); eZ[CqUJ&  
^cZF#%k  
9jDV]!N4  
int responseCode=httpConnection.getResponseCode(); +6B(LPxgP  
if(responseCode>=400) 6^H64jM  
{ 2IFri|;-eb  
processErrorCode(responseCode); ^' lx5+-  
return -2; //-2 represent access is error Dq)V] Zx  
} UAFl+d!  
*Y?rls`  
<T)9mJYr  
String sHeader; WB'&W=  
-m(9*b{h@  
O"<D0xzF?  
for(int i=1;;i++) 0vbn!<:  
{ $z1u>{  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 7m~+HM\  
//Utility.log(in.readLine()); Uq<c+4)5  
sHeader=httpConnection.getHeaderFieldKey(i); (x@|6Sb  
if(sHeader!=null) o|>2X[T  
{ \L}Soe'  
if(sHeader.equals("Content-Length")) f>s3Q\+  
{ 2oXsPrtZ  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *TfXMN ?w  
break; r,(rWptf4  
} $iUK, ?  
} rZLTai}`>  
else Y/2@PzA|  
break; +XLy Pj  
} KqG:o+V=  
} J/>Y mi,  
catch(IOException e){e.printStackTrace ();} b/:9^&z  
catch(Exception e){e.printStackTrace ();} #Q.A)5_  
"EQ`Q=8  
cgNK67"(  
Utility.log(nFileLength); - K0>^2hh  
/csj(8^w  
c/DB"_}!a  
return nFileLength; 0.'$U}#b  
} 1.+0=M[h  
` Xc~'zG  
TppR \[4]  
//保存下载信息(文件指针位置) {" woBOaA  
private void write_nPos() (n;#Z,  
{ =H%c/Jty  
try{ g,h'K  
output = new DataOutputStream(new FileOutputStream(tmpFile)); -Ob'/d5&  
output.writeInt(nStartPos.length); i^eU!^KF  
for(int i=0;i<nStartPos.length;i++) z|^:1ov,  
{ 3,DUT{2  
// output.writeLong(nPos); \HF|&@}hU  
output.writeLong(fileSplitterFetch.nStartPos); w!,~#hbt6  
output.writeLong(fileSplitterFetch.nEndPos); }b)7gd=  
} vOy;=0$  
output.close(); 2a'b}<|[(  
} ekND>Qjj  
catch(IOException e){e.printStackTrace ();} 8iaP(*J  
catch(Exception e){e.printStackTrace ();} y!&6"l$K]  
} .aV#W@iyK  
qF C0$:z&  
.|^L\L(!  
//读取保存的下载信息(文件指针位置) 1v)ur\>R  
private void read_nPos() m^Qc9s#D  
{ \2KwF}[m  
try{ 48vKUAzx`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); I(y:Td  
int nCount = input.readInt(); 4/vQ/>c2j  
nStartPos = new long[nCount]; V]dzKNFi  
nEndPos = new long[nCount]; lK;|ciq"c7  
for(int i=0;i<nStartPos.length;i++) ?9'Ukw` g  
{ Xb6X'rY  
nStartPos = input.readLong(); L}5nq@Uu)  
nEndPos = input.readLong(); .xo#rt9_"=  
} i}"Eu< P  
input.close(); EVZuwbO)|  
} &o%IKB@  
catch(IOException e){e.printStackTrace ();} 2L Kpwz?  
catch(Exception e){e.printStackTrace ();} L}Nc kL  
} 5V5Nx(31i  
.`*h2  
Y` t-Bg!~  
private void processErrorCode(int nErrorCode) Teh _  
{ 04g=bJ  
System.err.println("Error Code : " + nErrorCode); +AkAMZ"Mg  
} q;a"M7  
$L%gQkz_  
t1"-3afe  
//停止文件下载 xo3bY6<n  
public void siteStop() V_+XZ+7Lx}  
{ }GI8p* ]o=  
bStop = true; *{[jO&& J  
for(int i=0;i<nStartPos.length;i++) t)o!OEnE  
fileSplitterFetch.splitterStop(); KnK8\p88\  
kEiWE|  
uflRW+-2  
} Mtxn@m{i;"  
} }8tD|t[  
//负责部分文件的抓取 a^/j&9  
**FileSplitterFetch.java 4+46z|  
*/ 1~rZka[s  
package NetFox; s\&qvL1D  
}\Kki  
ukNB#2 "  
import java.io.*; .rpKSf.  
import java.net.*; |uL"/cMW7  
6WUP#c@{  
L-SWs8  
public class FileSplitterFetch extends Thread { ,xmL[Yk,  
6j uNn}  
#$k6OlK-r"  
String sURL; //File URL xg*)o*?  
long nStartPos; //File Snippet Start Position S 2vjjS  
long nEndPos; //File Snippet End Position %z1y3I|`[t  
int nThreadID; //Thread's ID $;~  
boolean bDownOver = false; //Downing is over %49 ^S&  
boolean bStop = false; //Stop identical ))Q3;mI"  
FileAccessI fileAccessI = null; //File Access interface K`%{(^}.  
~Psv[b=]  
uRIa Nwohv  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException a(cZ]`s]*  
{ JSO'. [N  
this.sURL = sURL; w K)/m`{g  
this.nStartPos = nStart; o m9zb&{tu  
this.nEndPos = nEnd; +2X q+P  
nThreadID = id; wP-BaB$_  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Y243mq-  
} i_<Uk8  
R/5@*mv{  
j\SvfZ0"  
public void run() Y9^;TQ+#  
{ ;F3#AO4(  
while(nStartPos < nEndPos && !bStop) |,ws3  
{ yex4A)n9"'  
_pZ2^OO@  
gxa@da  
try{ c ow]qe6K  
URL url = new URL(sURL); iLhxcM2K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ftr?@^  
httpConnection.setRequestProperty("User-Agent","NetFox"); +2&+Gh.h  
String sProperty = "bytes="+nStartPos+"-"; +,wCV2>\3  
httpConnection.setRequestProperty("RANGE",sProperty); [*i6?5}-  
Utility.log(sProperty); znVao %b  
Fkq;Q  
LS(J%\hMDm  
InputStream input = httpConnection.getInputStream(); 6KpG,%2L#  
//logResponseHead(httpConnection); b`%(.&  
22`N(_  
.|d2s  
byte[] b = new byte[1024]; H<YhO&D*u  
int nRead; Ic!8$NhRS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) L"Vi:zdp  
{ f3bZ*G%f  
nStartPos += fileAccessI.write(b,0,nRead); B`I9  
//if(nThreadID == 1) fG{ 9doUD  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d]bM,`K* 6  
} H6fR6Kr4j  
XMJEIG  
(j*1sk  
Utility.log("Thread " + nThreadID + " is over!"); J|Af`HJ  
bDownOver = true; .WeP]dX%:f  
//nPos = fileAccessI.write (b,0,nRead); xW hi>  
} }iu(-{Z  
catch(Exception e){e.printStackTrace ();} ;8VvpO^G/  
} 3B+ F'k&#  
} =5 zx]N1r  
BkO)hze  
+[2X@J  
//打印回应的头信息 Po+tk5}''5  
public void logResponseHead(HttpURLConnection con) h~ F`[G/'  
{ !"dn!X  
for(int i=1;;i++)  ~wX4j  
{ ]t'bd <O  
String header=con.getHeaderFieldKey(i); xQKD1#y  
if(header!=null) ab5uZ0@  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); pN]$|#%q(  
Utility.log(header+" : "+con.getHeaderField(header)); [>pqf  
else Y64B"J=P 9  
break; "-tTN  
} *, Mg  
} x>E**a?!L  
6Eu&%`  
m{ya%F  
public void splitterStop() ^Z 9v_qB  
{ =z]8;<=pL  
bStop = true; JW`Kh*,~<  
} ~w>Z !RuhT  
]0g%)fuMf  
|H(Mmqgk  
} [;]@PKW?w  
JN{xh0*  
_tGR:E  
/* e1k\:]6  
**FileAccess.java cuw3}4m%  
*//文件访问(定位,写) 8/4Gr8 o  
package NetFox; wG&+*,}  
import java.io.*; HOb-q|w  
H=7z d|W  
[xVE0l*\   
public class FileAccessI implements Serializable{  ;7F|g  
H$ sNp\[{  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 .W>8bg'u9  
RandomAccessFile oSavedFile; 7%(|)3"V  
long nPos; B-OuBS,fwC  
T21SuM  
0H V-e  
public FileAccessI() throws IOException j&S8x|5  
{ 4't@i1Ll(  
this("",0); yL&_>cV  
} u D.E>.B  
kS>'6xXH  
~'4:{xH  
public FileAccessI(String sName,long nPos) throws IOException R.g'&_zx  
{ kRk=8^."By  
oSavedFile = new RandomAccessFile(sName,"rw"); zn4Yo  
this.nPos = nPos; t?-7Z6  
oSavedFile.seek(nPos); j=^b'dyL  
} J6!t"eB+  
;,z^!bD  
g>[|/z P  
public synchronized int write(byte[] b,int nStart,int nLen) W biUz2)  
{ UeRx ^  
int n = -1; Xcq 9*!%o  
try{ kUJ\AK  
oSavedFile.write(b,nStart,nLen); GQ-o wH]  
n = nLen; #0-!P+c[  
} JuGQS24  
catch(IOException e) *5i~N}  
{ EO|r   
e.printStackTrace (); ))n7.pB9/  
} o(W|BD!  
mne^P SI:  
%qzpt{'?<  
return n; u+]v. Mt  
} |wf:|%  
zS:89y<  
F:/R'0  
} 5JbPB!5;  
?80@+y]  
+ R)x5  
/* uP/WRQ{rW>  
**SiteInfoBean.java ? OBe!NDf  
*/ ^i{B8]2,  
package NetFox; %*.;3;m  
^g,[#Rh  
cU25]V^{\  
public class SiteInfoBean { 5 TD"  
lLHHuQpuj  
xG_ ;F  
private String sSiteURL; //Site's URL {rWu`QT  
private String sFilePath; //Saved File's Path N0c+V["s  
private String sFileName; //Saved File's Name `8F%bc54iw  
private int nSplitter; //Count of Splited Downloading File ZkYc9!anY  
>GiM?*cC  
?6    
public SiteInfoBean() #K7i<Bf  
{//nSplitter的缺省值为5 !MB%  
//default value of nSplitter is 5 &7 }!U  
this("","","",5); OwP9=9};  
} L%a ni}V  
tg~&kaz  
66=6;77  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) E{r_CR+8  
{ ,_T,B'a:  
sSiteURL= sURL; [;VNuF  
sFilePath = sPath; _Z6/r^c  
sFileName = sName; r0kA47  
this.nSplitter = nSpiltter; J+&AtGq]u  
J p .wg  
CF^7 {g(y_  
} -8tWc]c |4  
zQ {g~x  
GI$t8{M  
public String getSSiteURL() ',0~\V  
{ vjJ!d#8  
return sSiteURL; Cc]s94  
} ~}4o=O(  
^h^2='p  
+byw*Kk  
public void setSSiteURL(String value) !23W=N}82  
{ }i/&m&VU  
sSiteURL = value; F|V_i C+  
} +D4Nu+~BSN  
w\_NrsO!x  
0|{U"\  
public String getSFilePath() ]t1)8v2w>  
{ N|Ua|^  
return sFilePath; ##u+[ !  
} q y y.3-(  
7F`QN18>(  
7& k lX  
public void setSFilePath(String value) )+ Wr- Yay  
{ 1l\O9D +$  
sFilePath = value; nl5K1!1  
} yQhrPw> m  
a-Cp"pKlVY  
PZpwi?N  
public String getSFileName() ~>D;2 S(a  
{ d"XS;;l%<  
return sFileName; 5]; 8  
} ;k7` `  
]Vl5v5_  
Ats"iV  
public void setSFileName(String value) {<~XwJ.  
{ z.Y7u3K.8  
sFileName = value; HcHfwLin0  
} %8$JL=c  
^i-%FY_i5}  
\9se~tAl3  
public int getNSplitter() j Xi<ZJ  
{ -5v c0"?E  
return nSplitter; o^&; `XOd  
} N,'JQch},8  
(L|SE4  
[X^JV/R  
public void setNSplitter(int nCount) v.6" <nT2  
{ =]xNpX)  
nSplitter = nCount; .1I];Cy0D  
} r'&9'rir2  
} 9aZ3W<N`M  
kc8GnKM&mc  
>Fx$Rty  
/* h#]}J}si  
**Utility.java /gy;~eB01  
*/ (:+IS W  
package NetFox; h,140pW  
4C01=,6ye  
-ZQ3^'f:0J  
public class Utility { @aCg1Rm  
)r?i^D&4  
\U !<-  
public Utility() 4N$s vA  
{ a2=wJhk  
Y[s  
-&,NM  
} x0lX6 |D  
;%dkwKO  
//线程睡眠 i'e^[oZ  
public static void sleep(int nSecond) Vg \-^$  
{ QwT ]| 6>  
try{ qZ\zsOnp  
Thread.sleep(nSecond); ~d5"<`<^o  
} _\]D<\St  
catch(Exception e) z(\H.P#  
{ oSa FmP  
e.printStackTrace (); 34;c00  
} CdaB.xk  
} >D:S)"  
6{7O  
//日志 XIjSwR kYJ  
public static void log(String sMsg) 3:Z(tM&-O  
{ m]"YR_  
System.err.println(sMsg); 3l L:vD5(  
} B.P64"w  
"BFW&<1  
'|XP}V0I  
public static void log(int sMsg) X2@o"xU  
{ $}KYpSV  
System.err.println(sMsg); @{CpC  
} :>3&"T.  
} U1q$B32  
+:'Po.{"  
zi-+@9T  
/* TS[Z<m  
**TestMethod.java b$$XriD]  
*/ wd#AA#J;*  
package NetFox; yPQ{tS*t  
+'n1?^U  
/pk; E$qv  
public class TestMethod { e0$mu?wd-  
(QRl -| +  
l&|{uk  
public TestMethod() NXmj<azED  
{ ///xx/weblogic60b2_win.exe teB {GR  
try{ _b5iR<f  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); WX=+\`NyJ(  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); kcOpO<oE  
SiteFileFetch fileFetch = new SiteFileFetch(bean); @B^'W'&C  
fileFetch.start(); ]yIy~V  
} <.v6w*+{/  
catch(Exception e){e.printStackTrace ();} n9J>yud|  
[KE4wz+s{  
BuvBSLC~  
} B0KM~cCPQP  
g8x8u|  
\)#3S $L~  
public static void main(String[] args) Q` s(T  
{ * ;M?R?+  
new TestMethod(); )xK!i.  
} b,`\"'1  
} nWl0R=  
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