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http断点续传简单实现(java)

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/* .(gT+5[  
**SiteFileFetch.java USHlb#*  
*/ _E x*%Qf.  
package NetFox; Q]2sj:  
import java.io.*; hi4h0\L!}  
import java.net.*; *Bb|N--jI  
q.u[g0h;  
YU ]G5\UU  
public class SiteFileFetch extends Thread { b7>,-O  
[qjAq@@N#q  
EL2hD$  
SiteInfoBean siteInfoBean = null; //文件信息Bean  YiY&; )w  
long[] nStartPos; //开始位置 l&e5_]+%  
long[] nEndPos; //结束位置 ? bUpK  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ]%WD} 4e  
long nFileLength; //文件长度 }]Gi@Nh|o  
boolean bFirst = true; //是否第一次取文件 76u/WC>B  
boolean bStop = false; //停止标志 Bsih<`KF^  
File tmpFile; //文件下载的临时信息 Mo?t[]L   
DataOutputStream output; //输出到文件的输出流 D-2v>l_  
Bp=oTC G  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ZmYSi$B  
public SiteFileFetch(SiteInfoBean bean) throws IOException e$FAhwpon  
{ :!Y?j{sGU  
siteInfoBean = bean; _taHf %\4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); `K@df<}%*,  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); d-#u/{jG)  
if(tmpFile.exists ()) #*7/05)  
{ &?5{z\;1"  
bFirst = false; uZ=UBir  
read_nPos(); g~$GE},,  
} U||w6:W5  
else #sm_.?P  
{ Zh fD`@>&  
nStartPos = new long[bean.getNSplitter()]; ="'P=Xh!8  
nEndPos = new long[bean.getNSplitter()]; fa*H cz  
} ,:dEEL+>c  
a2 klOX{  
nDoiG#N0  
HqnKpZ  
} N8MlT \+r  
c|!A?>O?i  
zvK5Zxl  
public void run() YKX>@)Dxv  
{ 4, *^QK  
//获得文件长度 bN7UO  
//分割文件 yBD2  
//实例FileSplitterFetch h3;o!FF  
//启动FileSplitterFetch线程 >b!X&JU  
//等待子线程返回 Jv4D^>yj[  
try{ +DbWMm  
if(bFirst) "o5gQTwb  
{ mC[U)` ey  
nFileLength = getFileSize(); *n|0\V<  
if(nFileLength == -1) tci%=3,)  
{ w?$u!X  
System.err.println("File Length is not known!"); @7[.> I(  
} /qz "I-a  
else if(nFileLength == -2) |au qj2  
{ E23 Yk?"  
System.err.println("File is not access!"); >fZ/09&3  
} \w0b"p  
else +GPT:\*q6  
{ ~b6<uRnM.  
for(int i=0;i<nStartPos.length;i++) k vgs $  
{ ,w b|?>Y  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); fj t_9-.  
} $ DZQdhv  
for(int i=0;i<nEndPos.length-1;i++) 1N$gE  
{ ]Re~V{uh  
nEndPos = nStartPos[i+1]; b]g&rwXYt  
} t+4Y3*WeGF  
nEndPos[nEndPos.length-1] = nFileLength; (HrkUkw  
} f;tyoN0wHx  
} mTuB*  
 \#+2;L  
VgZaDd;  
//启动子线程 ID)gq_k[8,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Uh|__DUkh  
for(int i=0;i<nStartPos.length;i++) }MavI'  
{ w[$nO#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,M/#Q6P0}  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), va/4q+1GfH  
nStartPos,nEndPos,i); L..X)-D2 n  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); j_a~)o-p  
fileSplitterFetch.start(); 6 XOu~+7  
} iZq@W3GL C  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), _l{ 5 'm  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); ,I&0#+}n  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 548 [! p4  
nEndPos = " + nFileLength); EAd:`X,Y  
// fileSplitterFetch[nPos.length-1].start(); =Z>V}`n  
UK <DcM~n  
L5k>;|SA  
//等待子线程结束 hte9l)  
//int count = 0; c>i*HN}Z|  
//是否结束while循环 ox=7N{+`J  
boolean breakWhile = false; F)5B[.ce  
~h^}W$pO  
?.Yw%{?TG  
while(!bStop) ;`PkmAg  
{ PSQ:'  
write_nPos(); `jQ}^wEgu  
Utility.sleep(500); &<P^Tvqq&  
breakWhile = true; 4bFVyv  
R5;eR(24G  
`i)ePiE  
for(int i=0;i<nStartPos.length;i++) ]z q_gV8k  
{ Nj-rZ%&  
if(!fileSplitterFetch.bDownOver) c.{&~  
{ Nb!6YY=Ez-  
breakWhile = false; eZod}~J8  
break; ocuVDC  
} |o=\9:wV  
} v4>"p!_C  
if(breakWhile) x^O2Lj,w\  
break; 7f Tg97eF  
Is6']bYh  
^'I5]cRa  
//count++; ^YJ^+:D(  
//if(count>4) -b>O4_N  
// siteStop(); n `T[eb~  
} %FWfiFV|<  
(F '  
A{Htpm~  
System.err.println("文件下载结束!"); )>M@hIV5>  
} Y7V&zF{  
catch(Exception e){e.printStackTrace ();} 1gy}E=noP  
} cYwC,\ uF  
BvW gH.OX  
n25tr'=  
//获得文件长度 JX0_UU  
public long getFileSize() y3[)zv  
{ ;6 qdOD6  
int nFileLength = -1; *;yMD-=  
try{ = 4WZr  
URL url = new URL(siteInfoBean.getSSiteURL()); 2d;xAX]  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); "X(=  
httpConnection.setRequestProperty("User-Agent","NetFox"); !@Vp Bl  
>Wit"p  
Qp{-!*  
int responseCode=httpConnection.getResponseCode(); 6ym)F!t8l  
if(responseCode>=400) s&`XK$p  
{ hG;=ci3EE  
processErrorCode(responseCode); ^RAFmM#F  
return -2; //-2 represent access is error >;r05,mc  
} dlzamoS@AR  
DD$P r&~=  
Ru')X{]25  
String sHeader; )zt4'b\)v  
<$6'Mzf  
z(X6%p0  
for(int i=1;;i++) j"sO<Q{6%  
{ 5YH mp7c-z  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); wVJFA1  
//Utility.log(in.readLine()); A^@<+?  
sHeader=httpConnection.getHeaderFieldKey(i); L.:QI<n  
if(sHeader!=null) ]bE?n.NwZ  
{ Hpg;?xAT  
if(sHeader.equals("Content-Length")) b-zX3R;  
{ gG;W:vR}l  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); to|9)\  
break; M*6@1.n  
} LbbQ3$@ WD  
} {bW3%iU  
else ~tuFjj^  
break; _";pk  _  
} xy3%z  
} vl~   
catch(IOException e){e.printStackTrace ();} }Q^a.`h  
catch(Exception e){e.printStackTrace ();} *>$)#?t  
[IBk-opap  
@CI6$  
Utility.log(nFileLength); GiwA$^Hg\  
\\Tp40m+  
"[S 6w  
return nFileLength; gbf=H8]  
} LhRe?U\  
k[)@I;m  
E(LE*J  
//保存下载信息(文件指针位置) V(uRKu x  
private void write_nPos() Z2jb>%  
{ `80Hxp@  
try{ 5@%-=87S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); y+afUJT  
output.writeInt(nStartPos.length); /(pChY>  
for(int i=0;i<nStartPos.length;i++) Ht^2)~e~:  
{ M #&L@fg!  
// output.writeLong(nPos); c!^}!32j)  
output.writeLong(fileSplitterFetch.nStartPos); V>92/w.fe  
output.writeLong(fileSplitterFetch.nEndPos); Fh $&puF2  
} 9?$!=4  
output.close(); RAbq_^Q  
} %<|KJb4?  
catch(IOException e){e.printStackTrace ();} X2?_lZ[\  
catch(Exception e){e.printStackTrace ();} a`iAA1HJ  
} 1ZFSz{  
E"&9FxS]^  
jUSr t)o03  
//读取保存的下载信息(文件指针位置) 8~#Q *  
private void read_nPos() /-4B)mL  
{ %\&dFwb  
try{ t+J6P)=  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Wj=ex3K3u.  
int nCount = input.readInt(); + qqN  
nStartPos = new long[nCount]; $i>VI  
nEndPos = new long[nCount]; M?zAkHNS$  
for(int i=0;i<nStartPos.length;i++) {=7i}xY]T  
{ 1^^D :tt  
nStartPos = input.readLong(); S Tk#hhx  
nEndPos = input.readLong(); >D62l*VC)  
} r!,V_a4n  
input.close(); zL8A?G)= M  
} @2*6+w_Ae  
catch(IOException e){e.printStackTrace ();} Kp8T;&<Iay  
catch(Exception e){e.printStackTrace ();} s2=X>,kz?  
} &ru0i@?)  
695ppiKU  
nW'x#0-  
private void processErrorCode(int nErrorCode) vGT.(:\-,  
{ }*R6p?L5  
System.err.println("Error Code : " + nErrorCode); 7"i*J6y*  
} eJp-s" %  
9'h^59  
M6#(F7hB  
//停止文件下载 ~' =4K/39  
public void siteStop() p,Hk"DSs%  
{ M[_I16s  
bStop = true; BmX Gk  
for(int i=0;i<nStartPos.length;i++) AB\4+ CLV  
fileSplitterFetch.splitterStop(); L]<4{8H.  
TJ:Lz]l >  
UdJV;T'rm  
} 26K~m@  
} :q1r2&ne  
//负责部分文件的抓取 MV \zwH  
**FileSplitterFetch.java  U~t(YT  
*/ ]t;5kj/  
package NetFox; ]bweQw@i  
TeqsP1{?  
j~q`xv+R  
import java.io.*; Mwc3@  
import java.net.*; D/UGN+  
\"Iy <zG  
Dx'e+Bm  
public class FileSplitterFetch extends Thread { c iX2G  
'v  X"l  
,$-PC=Ti(  
String sURL; //File URL L9oZ7o  
long nStartPos; //File Snippet Start Position u`|fmVI  
long nEndPos; //File Snippet End Position \]%U?`A  
int nThreadID; //Thread's ID Y&:i^k  
boolean bDownOver = false; //Downing is over `Cxe`w4  
boolean bStop = false; //Stop identical >O~5s.1u  
FileAccessI fileAccessI = null; //File Access interface qr6jn14.c  
CV"Y40  
Hp!F?J7sx  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException g"Bv!9*H  
{ !d(V7`8  
this.sURL = sURL; eVXbYv=gJ@  
this.nStartPos = nStart; idy:Jei}  
this.nEndPos = nEnd; .SN]hLV5  
nThreadID = id; !&[4T#c  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 X2v'9 x  
} Z]BR Mx  
6< Z9p@6  
e.V){}{V  
public void run() e AjtWqg  
{ [dMxr9M  
while(nStartPos < nEndPos && !bStop) :^a$ve3(Jq  
{ (xL=X%6a  
i;Y^}2   
n TG|Isa  
try{ sSUd;BYf  
URL url = new URL(sURL); aDuanGC/V  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); W(YJz#]6_  
httpConnection.setRequestProperty("User-Agent","NetFox"); Kq$1lPI  
String sProperty = "bytes="+nStartPos+"-"; 7ZZt|bl  
httpConnection.setRequestProperty("RANGE",sProperty); {wI0 =U  
Utility.log(sProperty); HrGX-6`  
J?'!8,RX  
X)m2{@v D  
InputStream input = httpConnection.getInputStream(); \ua.%|  
//logResponseHead(httpConnection); :xCobMs_/  
ny=iAZM>q  
*en{pR'  
byte[] b = new byte[1024]; fF%r$`2  
int nRead; x}d\%* B  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 'oG'`ED"  
{ O5 SX"A  
nStartPos += fileAccessI.write(b,0,nRead); 1~ Nz6  
//if(nThreadID == 1) M .,|cx  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 2uIAnbW]M  
} vaL-Mi(_  
z@~rm9d  
)f Rh^6  
Utility.log("Thread " + nThreadID + " is over!"); 5S LF1u;  
bDownOver = true; {Hu0  
//nPos = fileAccessI.write (b,0,nRead);  >pKI'  
} Gj=il-Po  
catch(Exception e){e.printStackTrace ();} Ry C7  
} bxs@_fH  
} A7H=#L+C  
R 9(^CWs  
-|mABHjx*  
//打印回应的头信息 GF&"nW9A  
public void logResponseHead(HttpURLConnection con) 5 *_#"  
{ Wm 61  
for(int i=1;;i++) s/V[tEC*z  
{ )1/O_N6C  
String header=con.getHeaderFieldKey(i); ^gG,}GTl  
if(header!=null) rQJoaP+\q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); YC~+r8ME$j  
Utility.log(header+" : "+con.getHeaderField(header)); F/8y p<_r  
else 6]VTn-  
break; iYnt:C  
} x>cu<,e$d\  
} pN[i%\vh  
\XC1/LZQ  
c{~*\&  
public void splitterStop() *L=CJg  
{ v&Kw 3!X#E  
bStop = true; ^s5)FdF8  
} 2;/hFwm  
4y 'REC  
":OXs9Yg  
} 5zU$_M  
9V~yK?  
g:HIiGN0Ic  
/* 2sngi@\  
**FileAccess.java A.n1|Q#  
*//文件访问(定位,写) RW 5T}  
package NetFox; y}A-o_u@cD  
import java.io.*; Liofv4![  
f&:g{K  
sMZ \6  
public class FileAccessI implements Serializable{ ~c4Y*]J  
Z\x6  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 "'%x|nB  
RandomAccessFile oSavedFile; xfb%bkr  
long nPos; J#\/znT  
?G@%haqn6  
a`}-^;}SW  
public FileAccessI() throws IOException I/'>Bn+  
{ rie1F,  
this("",0); \C#Vh7z"2&  
} ]BA8[2=m  
'2NeuK-KD  
--FvE|I  
public FileAccessI(String sName,long nPos) throws IOException T"O!  
{ '?\Hm'8  
oSavedFile = new RandomAccessFile(sName,"rw"); "xWC49   
this.nPos = nPos; 61wiXX"N  
oSavedFile.seek(nPos); [X|P(&\hQd  
} @uc%]V<:k  
m|!sY[!  
;kY=}=9  
public synchronized int write(byte[] b,int nStart,int nLen) 7{6wNc  
{ fy-( B;  
int n = -1; epQ7@9,Q  
try{ yt?# T #  
oSavedFile.write(b,nStart,nLen); X]N8'Yt  
n = nLen; Mf?4 `LM  
} -Jb I7Le  
catch(IOException e) #p^D([k \  
{ \o/oM,u  
e.printStackTrace (); PWTAy\  
} hSxf;>(d  
p0Vw@R=  
mV-MJ$3r  
return n; Ba"Z^(:  
} &4DWLI  
~U`aH~R  
gX[6WB"p  
} y<)x`&pcD  
EM"YjC)F  
#6JG#!W  
/* /gxwp:&lY  
**SiteInfoBean.java [K^RC;}nV^  
*/ 'INdZ8j_  
package NetFox; tYnNOK*|  
xSw ^v6!2  
Ax&+UxQ0|  
public class SiteInfoBean { +?%huJYK,  
W )\~T:Kn  
X4jtti  
private String sSiteURL; //Site's URL #U^@)g6  
private String sFilePath; //Saved File's Path Rt+s\MC^r  
private String sFileName; //Saved File's Name <=WQs2  
private int nSplitter; //Count of Splited Downloading File )AnX[:y  
lE4.O  
Y #KgaZ7N  
public SiteInfoBean() %0L 9)-R  
{//nSplitter的缺省值为5 < d?O#(  
//default value of nSplitter is 5 UtzW5{  
this("","","",5); |@Bl?Bs+  
} (%tKGeb  
vFQ'sd]C  
 1D6iJ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) u\50,N9Wp{  
{ YI|7a#*F  
sSiteURL= sURL; leiP/D6s  
sFilePath = sPath; jfk`%C Ek=  
sFileName = sName; fF ;-d2mF  
this.nSplitter = nSpiltter; fxjs"rD5  
%{axoGd  
 a(F%M  
} A%pcPzG;  
XJGOX n$/  
7Y:1ji0l  
public String getSSiteURL() QDs]{F#  
{ JBp^@j{_  
return sSiteURL; /.P*%'g  
} I U/gYFT  
Y7 = *-  
"+p_{J/P  
public void setSSiteURL(String value) b3W@{je  
{ ;:f.a(~c  
sSiteURL = value; ;8H m#p7,  
} 7&E3d P  
sT|8a  
OT+LQ TE  
public String getSFilePath() @a+1Ri`)  
{ I6~.sTl  
return sFilePath; = oQ-I  
} y^?7de}  
h49|x&03  
.hXxh)F  
public void setSFilePath(String value) ) m[0,  
{ |X0h-kX4  
sFilePath = value; 5?{a=r9  
} NZ7g}+GTG  
xM'bb5  
eNR>W>;'  
public String getSFileName() `;L>[\Xi  
{ ihdN{Mx<2  
return sFileName; Y:XE4v/)@L  
} /0IvvD!7N  
HTA Jn_  
D:4Iex9$F"  
public void setSFileName(String value) (w}iEm\b  
{ )[i0~o[  
sFileName = value; LY(YgqL  
} B|zJrz0q3  
r>+\9q1  
r3*0`Rup  
public int getNSplitter() A}W) La\  
{ !RN(/ &%y  
return nSplitter; v'mRch)d  
} B agO0#  
a"@k11  
x\T 9V~8a  
public void setNSplitter(int nCount) jhl9  
{ /_rEI,[k  
nSplitter = nCount; ]c4?-Vq%u  
} gMS-mkZ  
} 3 - Nwg9 U  
B&3oo   
Iy% fg',%  
/* xEb+sE6Z  
**Utility.java MOi.bHCQJP  
*/ %ukFn &-2@  
package NetFox; n]S DpptM  
DryN}EMOKD  
MEf`&<t  
public class Utility { M{w[hV  
>+ZBQ]~  
FxeDjAP  
public Utility() [uqe|< :  
{ Q8OA{EUtq  
>$Sc}a3  
:sDE 'o  
} 9$U@h7|Q`  
TrD2:N}dI  
//线程睡眠 Er509zZ,[  
public static void sleep(int nSecond) 1j"_@?H[  
{ &3~lZa;D  
try{ B)>r~v]  
Thread.sleep(nSecond); cAnL,?_v  
} Q$u&/g3NvL  
catch(Exception e) qz[qjGdHg  
{ YW9r'{(D(I  
e.printStackTrace (); B8_)I.  
} WZ,}]D  
} <?yf<G'$  
dp;;20z  
//日志 F<H[-k*t/  
public static void log(String sMsg) Av6=q=D  
{ 4j+FDc`  
System.err.println(sMsg); ])Rs.Y{Q5  
} JWQd/  
5yBaxw`  
j=c=Pe"?u  
public static void log(int sMsg) 7m='-_w)?w  
{ r?Q`b2Q  
System.err.println(sMsg); xgeDfpF'  
} 4u0\|e@a  
} NEp )V'  
z 3((L  
d+DdDr  
/* +pMa-{  
**TestMethod.java Zfwhg4G~  
*/ vfBIQfH  
package NetFox; T .#cd1b  
*XN|ZGl/  
[ =/Yo1:v  
public class TestMethod { 4PdJ  
Em6P6D>S>,  
vl}fC@%WRI  
public TestMethod() TEB<ia3+  
{ ///xx/weblogic60b2_win.exe ,yPs4',d  
try{ Z!#n55 |  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); zt,Tda4Y  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); %*:X FB  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Qk`ykTS!  
fileFetch.start(); iB-h3/  
} <;eXbO>Q  
catch(Exception e){e.printStackTrace ();} $+'bRUo  
%PF:OB6[|  
ayGYVYi  
} %3SBs*?  
Lvco9 Ak  
M( eu wy  
public static void main(String[] args) HgVPyo  
{ *aem5 E`c  
new TestMethod(); skSs|slp  
} 3jeB\  
} Gz09#nFZk  
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