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http断点续传简单实现(java)

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/* _Hj,;Z  
**SiteFileFetch.java !qve1H4d2  
*/ [6N39G$  
package NetFox; VO?NrKyeW  
import java.io.*; :?W:'% (`[  
import java.net.*; 8[IifF1M=&  
>9|+F [Fc  
)Q?[_<1Y+  
public class SiteFileFetch extends Thread { lI<8)42yq  
kO"aE~  
-e\56%\~_  
SiteInfoBean siteInfoBean = null; //文件信息Bean Vk T3_f  
long[] nStartPos; //开始位置 ZA@"uqa6b  
long[] nEndPos; //结束位置 '2oBi6|X  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 vLS6Gb't  
long nFileLength; //文件长度 dBn.DU*B  
boolean bFirst = true; //是否第一次取文件 `d#_66TLr  
boolean bStop = false; //停止标志 +=$G6uR$  
File tmpFile; //文件下载的临时信息 j'n= Xh  
DataOutputStream output; //输出到文件的输出流 n8,/olqwW  
QV1%Zou  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) [}3Y1t{G  
public SiteFileFetch(SiteInfoBean bean) throws IOException j pV  
{ 1!#ZEI C  
siteInfoBean = bean; \zyGJyy.  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); xbA2R4|  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 3|3lUU\I  
if(tmpFile.exists ()) &t4(86Bmq  
{ Vd~k4  
bFirst = false; +N:%`9}2V  
read_nPos(); 0[Aa2H*  
} h 42?^mV4?  
else Y [S^&pF  
{ FFGTIT# {"  
nStartPos = new long[bean.getNSplitter()]; (^\i(cfu6Q  
nEndPos = new long[bean.getNSplitter()]; ,_O[; L  
} +[+ Jd)Z  
u1<kdTxA N  
[%:NR  
Pp!W$C:  
} a}\JA`5;)Z  
p {3|W<  
N%y FL  
public void run() KQ3 On(d  
{ wS4wED&a  
//获得文件长度 I*"]!z1  
//分割文件 ;'}xD5]  
//实例FileSplitterFetch B;Vl+}R  
//启动FileSplitterFetch线程 Jsl,r+'H  
//等待子线程返回 R)z|("%ec  
try{ v>R.ou(  
if(bFirst) =c'LG   
{ [XK"$C]jHJ  
nFileLength = getFileSize(); &5<lQ1  
if(nFileLength == -1) EbHeP  
{ 2$=HDwv  
System.err.println("File Length is not known!"); HDOaN  
} ok'1  
else if(nFileLength == -2) k=[R o  
{ nceF4Ty  
System.err.println("File is not access!"); i`;I"oY4  
} 1;V5b+b  
else l?~h_8&fT  
{ 6G],t)<A'-  
for(int i=0;i<nStartPos.length;i++) :nt%z0_  
{ RZjR d  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); sM K/l @7  
} Ql 1# l:Q  
for(int i=0;i<nEndPos.length-1;i++) Mv3Ch'X[  
{ r{_'2Z_i  
nEndPos = nStartPos[i+1]; <[bDNe["?  
} Khl7Ez  
nEndPos[nEndPos.length-1] = nFileLength; XA68H!I  
} YX(%jcj*  
} W%o){+,  
x4K5  
V<7Gd8rDMM  
//启动子线程 8}"j#tDc  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 4w,}1uNEf  
for(int i=0;i<nStartPos.length;i++) 5I14"Qf  
{ !p$V7pFu6  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Yu=^`I  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), jQhf)B  
nStartPos,nEndPos,i); 03PVbDq-  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); =Ao;[j)*!  
fileSplitterFetch.start(); I~I%z'"RQd  
} qCMcN<:>  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), dGg+[?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yY+2;`CH  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6-~  
nEndPos = " + nFileLength); "?!IPX2\S  
// fileSplitterFetch[nPos.length-1].start(); foeVjL:T  
t j0vB]c  
Dcf`+?3  
//等待子线程结束 [Zf<r1m  
//int count = 0; cD\Qt9EI  
//是否结束while循环 V-31x)  
boolean breakWhile = false; ,\M'jV"S K  
LuVj9+1 S  
>cp9{+#f  
while(!bStop) m`|Z1CT  
{ Am0$UeSZ  
write_nPos(); T]xGE   
Utility.sleep(500); 6!$S1z#wM  
breakWhile = true; bu.36\78  
4}CRM# W2  
xl3U  
for(int i=0;i<nStartPos.length;i++) d dPJx<  
{ ra3WLK  
if(!fileSplitterFetch.bDownOver) BC+HP9<]  
{ ;u%hwlo  
breakWhile = false; )q,}jeM8  
break; :/3`+&T^/  
} v#6.VUAw  
} M3''xrpC  
if(breakWhile) |lv4X }H  
break; >@X=E3  
1;h>^NOq  
l @Ki`if  
//count++; YW5E |z  
//if(count>4) /X?Nv^Hy  
// siteStop(); Wi[Y@  
} ru&RL HFV  
!"kvXxp^  
-nW{$&5AF  
System.err.println("文件下载结束!"); lbPxZ'YO#  
} TcC=_je460  
catch(Exception e){e.printStackTrace ();} @ZVc!5J_,  
} 17GyE=Uu  
Xk3Ufz]QN  
1Nz\3]-  
//获得文件长度 ka hv1s-  
public long getFileSize() ?z6C8T~+  
{ L=$P  
int nFileLength = -1; fkYQ3d,`  
try{ OV[-m;h|  
URL url = new URL(siteInfoBean.getSSiteURL()); |!|`Je3 K  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 0K!9MDT}*  
httpConnection.setRequestProperty("User-Agent","NetFox"); yP-Dj ,  
>eXNw}_j  
|LQmdgVr$  
int responseCode=httpConnection.getResponseCode(); B[$e;h*Aw[  
if(responseCode>=400) g (~&  
{ D"hiEz  
processErrorCode(responseCode); yF:fxdpw  
return -2; //-2 represent access is error aZ'p:9e  
} , R)[$n  
OJ 2M_q)e  
$qvNv[  
String sHeader; Eg9502Bl~8  
_+{s^n=  
ql8:s>1T  
for(int i=1;;i++) s(dox; d  
{ G$Dg*<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); kSDV#8 uZ  
//Utility.log(in.readLine()); Z` Aiw."|  
sHeader=httpConnection.getHeaderFieldKey(i); czp5MU_^  
if(sHeader!=null) QhZ%<zN  
{ Ua:EI!`  
if(sHeader.equals("Content-Length")) t!~mbx+  
{  LKm5U6  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); TQ BL!w  
break; Pa.!:N-  
} ^'h~#7s  
} -{< %Wt9  
else B)(A#&nrb  
break; #qPk,a  
} C?|gf?1p  
} 1/gh\9h  
catch(IOException e){e.printStackTrace ();} 3drgB;:g`  
catch(Exception e){e.printStackTrace ();} Y5;:jYk#<_  
+V) (,f1  
QW!'A`*x  
Utility.log(nFileLength); y0Tb/&xN  
>?kt3.IQ!X  
qjWgyhL  
return nFileLength; JmBYD[h,  
} *)w 8fq  
J:>TV.TP  
T7,tJk,(  
//保存下载信息(文件指针位置) j_{gk"2:d`  
private void write_nPos() u]}Xq{ZN  
{ W=DQ6.   
try{ MDlC U  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 4, :D4WYWD  
output.writeInt(nStartPos.length); 7fVVU+y  
for(int i=0;i<nStartPos.length;i++) w"D"9 G  
{ X:dj5v  
// output.writeLong(nPos); Y 8P  
output.writeLong(fileSplitterFetch.nStartPos); [)a,rrhj  
output.writeLong(fileSplitterFetch.nEndPos); GY!&H"%  
} 9uq| VU5  
output.close(); A_g'9  
} -uh/W=Q1R  
catch(IOException e){e.printStackTrace ();} mF_/Rhu  
catch(Exception e){e.printStackTrace ();} $q+7 ,,"  
} -H]svOX  
$Fn# b|e  
:!|xg! |y  
//读取保存的下载信息(文件指针位置) 6"wY;E  
private void read_nPos() 0}ZuF.  
{ 41:Z8YL(  
try{ vEb~QX0~  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Ghj6&K%b0  
int nCount = input.readInt(); qaUHcdH  
nStartPos = new long[nCount]; \UiuJ+  
nEndPos = new long[nCount]; bi_R.sfK&  
for(int i=0;i<nStartPos.length;i++) hP|5q&wX  
{ /E*P0y~KTW  
nStartPos = input.readLong(); B}3s=+L@8  
nEndPos = input.readLong(); WgY3g1C  
} R&-bA3w$  
input.close(); { u;ntDr  
} CfVz'  
catch(IOException e){e.printStackTrace ();} 0/%zXp&m  
catch(Exception e){e.printStackTrace ();} Z8:iaP)  
} R; IB o  
-j(/5.a  
8>w/Es5  
private void processErrorCode(int nErrorCode) aB$Y5  
{ $k!t&G  
System.err.println("Error Code : " + nErrorCode); Y!SD^Ie7!  
} oc15!M3$  
`T mIrc  
Z(V 4"x7F  
//停止文件下载 tV<A u  
public void siteStop() F'Wef11Yz  
{ NSxDCTw  
bStop = true; 63at lq  
for(int i=0;i<nStartPos.length;i++) L-MpdC  
fileSplitterFetch.splitterStop(); fc M~4yP?  
;z&p(e  
N!P* B $d  
} jx-W$@  
} WjA)0HL(  
//负责部分文件的抓取 R=E )j^<F  
**FileSplitterFetch.java OnD+/I  
*/ DB?[h<^m  
package NetFox; uD+;5S]us  
}U8H4B~UtY  
`OBDx ^6F  
import java.io.*; u|Db%)[  
import java.net.*; aE:fMDS|x  
:FK(*BUh  
h883pe=  
public class FileSplitterFetch extends Thread { af> i  
Ar>-xCT D  
jtd{=[STU  
String sURL; //File URL hmks\eb~  
long nStartPos; //File Snippet Start Position BB~Qs  
long nEndPos; //File Snippet End Position {lqnn n3  
int nThreadID; //Thread's ID 0C3CqGP  
boolean bDownOver = false; //Downing is over &ts!D!Hj  
boolean bStop = false; //Stop identical TG'A'wXxy  
FileAccessI fileAccessI = null; //File Access interface l'$AmuGj  
> Y LwWU<X  
+]B^*99  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B:Msn)C~  
{ >\MV/!W  
this.sURL = sURL; u TOL  
this.nStartPos = nStart; $S6AqUk$  
this.nEndPos = nEnd; 3dC8MKPq0  
nThreadID = id; _4.fT  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 84|Hn|4t  
} xUj[d(q  
%1xo|6hm-  
5q" ;R$+j  
public void run() U JY`P4(  
{ *p+%&z_<  
while(nStartPos < nEndPos && !bStop) /J1O{L  
{ Av7bp[OD  
%  &{>oEQ  
t[7YMk  
try{ evZ{~v& /  
URL url = new URL(sURL); ~^:/t<N  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lshO'I+)*  
httpConnection.setRequestProperty("User-Agent","NetFox"); |f.=Y~aY  
String sProperty = "bytes="+nStartPos+"-"; X8F _Mb*  
httpConnection.setRequestProperty("RANGE",sProperty); 6?z&G6  
Utility.log(sProperty); 6]7iiQz"H  
7w YSP&$  
uB0/H=<H  
InputStream input = httpConnection.getInputStream(); J?u",a]|H"  
//logResponseHead(httpConnection); wvsTP32]  
/6b(w=pk  
3,W2CN}  
byte[] b = new byte[1024]; 1z0&+C3z  
int nRead; J3g>#N]='(  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) , )u}8ty3j  
{ RCnN+b:c  
nStartPos += fileAccessI.write(b,0,nRead); (\>_{"*=  
//if(nThreadID == 1) " #_NA`$i  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); @D Qg1|m  
} M"ZP s   
v`bX#\It  
pu,/GBG_  
Utility.log("Thread " + nThreadID + " is over!"); _ i.CvYe  
bDownOver = true; _hK7hvM>  
//nPos = fileAccessI.write (b,0,nRead); :/K 'P`JaL  
} ) ^!oM  
catch(Exception e){e.printStackTrace ();} ~`u?|+*BO  
} CSR 6  
} )d_)CuUBe  
qdjRw#LS^q  
|C\g3N-  
//打印回应的头信息 3@\vU~=P:  
public void logResponseHead(HttpURLConnection con) Yk6fr~b  
{ t? yMuK  
for(int i=1;;i++) o#4Wn'E  
{ b8feo'4Z   
String header=con.getHeaderFieldKey(i); cg}46)^<QH  
if(header!=null) 9Or3X/:o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 'w^1re= R  
Utility.log(header+" : "+con.getHeaderField(header));  J<V}g v  
else #<MLW4P  
break; :DR G=-M  
} ) Tpc8Hr  
} '[{M"S  
b'St14_  
BAx)R6kS;  
public void splitterStop() sO~N2  
{ hSQ P '6  
bStop = true; |Gzd|$%Oq  
} ph<Z/wlz  
P (_:8|E  
p}}}~ lC/  
} L/c$p`-  
ec)G~?FH  
"/O0j/lm  
/* OHR9u  
**FileAccess.java ]j}zN2[A  
*//文件访问(定位,写) lva]jh2  
package NetFox;  #Z"N\49  
import java.io.*; v'Tk Kwl  
B@63=a*kG  
vpMNulXb,  
public class FileAccessI implements Serializable{ n,9 *!1y  
O (tcu@vfl  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 3`5?Zgp  
RandomAccessFile oSavedFile; /thCu%%9A  
long nPos; }V ;PaX  
@433?g`2b  
13}=;4O  
public FileAccessI() throws IOException !Z<GUbl t  
{ KVSy^-."  
this("",0); s<sqO,!  
} eOZA2  
;TEZD70r  
YEXJ h!X  
public FileAccessI(String sName,long nPos) throws IOException 9 /t}S6b{  
{ 66[yL(*+  
oSavedFile = new RandomAccessFile(sName,"rw"); H \.EK Z  
this.nPos = nPos; 0;!aO.l]K  
oSavedFile.seek(nPos); tZk@ RX  
} (=)+as"u9*  
>M[rOu (d  
Oa$ ew'  
public synchronized int write(byte[] b,int nStart,int nLen) IgLP=mqcWK  
{ gA`/t e  
int n = -1; ?F(t`0=  
try{ MP w@O0QS  
oSavedFile.write(b,nStart,nLen); >Cb% `pe  
n = nLen; $_S^Aw?  
} 4Q z  
catch(IOException e) +S<2d.&~  
{ lh(A=hn"n  
e.printStackTrace (); 5u~Ik c~  
} kFw3'OZ,  
{1#5\t>9yD  
l!~8  
return n; ^X)U^Qd  
} x*}(l%[  
OC 7:Dp4  
@H]g_yw [:  
} 6 !+xf  
P`-(08t  
P7 (&*=V  
/* zblh_6  
**SiteInfoBean.java \7$m[h {l  
*/ w^A8ZT0^7  
package NetFox; |jEKUTv,G  
P2 !~}{-  
F2z^7n.S  
public class SiteInfoBean { Mff_j0D  
8p-5.GU)<e  
R+]Fh4t  
private String sSiteURL; //Site's URL P-7!\[];te  
private String sFilePath; //Saved File's Path wAF>C[<\  
private String sFileName; //Saved File's Name 96}/;e]@  
private int nSplitter; //Count of Splited Downloading File `w[0q?}"`  
a_x$I? ,  
I]~xs0$4#  
public SiteInfoBean() rv9qF |2r{  
{//nSplitter的缺省值为5 sOz jViv  
//default value of nSplitter is 5 '+f!(teLz  
this("","","",5); e4khReF;  
} rZKv:x}{6  
No =f&GVg  
'?_I-="Mr  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) iBV*GW  
{ qAivsYN*  
sSiteURL= sURL; .NQoqXR  
sFilePath = sPath; J4!Z,-  
sFileName = sName; &EE6<-B-  
this.nSplitter = nSpiltter; unSF;S<  
Q\m"n^XN  
5NJ@mm{0  
} E36<Wog  
ugVsp&i#  
!xj>~7  
public String getSSiteURL() ZH0 ~:  
{ ?mG ?N(t/h  
return sSiteURL; PM[6U#  
} k8Qv>z  
va~:oA  
_~HGMC)  
public void setSSiteURL(String value) `z Z=#p/  
{ e%wbUr]c2  
sSiteURL = value; [EB2o.E sO  
} B?#@<2*=L  
rH8?GR0<  
_q3SR[k+`  
public String getSFilePath() )Qw|)='-  
{ ln3x1^!  
return sFilePath; (0Hhn2JA  
} _L%/NXu,  
~ Z%>N  
A`#5pGR  
public void setSFilePath(String value) V0wK.^]+}/  
{ }9 qsPn  
sFilePath = value; XO"!)qF  
} #uuwzE*M_  
}gag?yQ.^  
Y($"i<rN  
public String getSFileName() /e4hB  
{ Qy0bp;V/  
return sFileName; !%T@DT=l&  
} &b"PjtU.X  
/5U?4l(6[f  
/3FC@?l w4  
public void setSFileName(String value) 5IVASqYp  
{ r[EN`AxDb  
sFileName = value; <0JW[m  
} <9\_b 6  
zh*NRN  
hh:0m\@<  
public int getNSplitter() Gx'mVC"{  
{ 2=["jP!B  
return nSplitter; KhXW5hS1  
} X+P3a/T  
;2#7"a^  
W5J"#^kdF8  
public void setNSplitter(int nCount) axXA y5  
{ :S~XE  
nSplitter = nCount; @HIC i]  
} j><.tA~i  
} li/IKS)e$  
_wZ(%(^I  
/x0zZ+}V  
/* M~ynJ@q  
**Utility.java A n/)|B4  
*/ ZLE4 XB]  
package NetFox; s49 AF  
w y:USS?  
pBK[j ([  
public class Utility { f{* G%  
5#QB&A>  
4V43(G  
public Utility() 9.vHnMcq  
{ @105 @9F  
CIO&VK  
`lcpUWn  
} ZuBVq  
pZjyzH{~  
//线程睡眠 ,((5|MbM/  
public static void sleep(int nSecond) SJy:5e?zk  
{ D?X97jNm  
try{ ?B@iBOcu[  
Thread.sleep(nSecond); =]Qu"nRB  
} @-!w,$F)%d  
catch(Exception e) 2)4{  
{ q SCt= eQ  
e.printStackTrace (); JK[7&C-O  
} t?YGGu^  
} olK%TM[Y  
.hETqE`E  
//日志 3<'SnP3mY  
public static void log(String sMsg) KY2xKco  
{  '=%vf  
System.err.println(sMsg); c @2s!bs  
} l$zo3[  
LR-op?W  
LL kAA?P  
public static void log(int sMsg) B1*%pjy  
{ "xnek8F  
System.err.println(sMsg); a&PoUwG  
} (Ozb+W?  
} L7a+ #mGE  
H'Z[3e  
T'f E4}rY  
/* P9X/yZ42  
**TestMethod.java ^[^uDE <  
*/ =0x[Sa$&,  
package NetFox; )0qXZ gs  
VPtA %1  
xJc'tT6@  
public class TestMethod { Yx XDRb\kW  
78}iNGf  
7<-D_$SrU  
public TestMethod() b$.N8W%  
{ ///xx/weblogic60b2_win.exe RFQa9Rxk  
try{ HYW+,ts'  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 1Voo($q.  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 4y%N(^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); d-xKm2sH  
fileFetch.start(); {9'"!fH  
} `|v0@-'$  
catch(Exception e){e.printStackTrace ();} _y5b>+  
%DzS~5$G  
{_ewc/~  
} Q$V xm+  
A+;]# 1y(D  
fwXk{P/  
public static void main(String[] args) `~pB1sS{  
{ 1 *;?uC\  
new TestMethod(); ^N0hc!$  
} WpSdukXY{  
} ZaXK=%z  
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