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http断点续传简单实现(java)

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/* bw7gL\*  
**SiteFileFetch.java {9x>@p/  
*/ ;f N^MW@&[  
package NetFox; T0)bnjm  
import java.io.*; )EKWsGNe/  
import java.net.*; .jtv Hr}U  
]+B.=mO_  
L%QRWhB  
public class SiteFileFetch extends Thread { &?Q^i">cZ  
6 v~nEw  
zDbO~.d  
SiteInfoBean siteInfoBean = null; //文件信息Bean tLq]#9kL  
long[] nStartPos; //开始位置 U[8F{LX  
long[] nEndPos; //结束位置 O|^J;fS:  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >kmgYWG  
long nFileLength; //文件长度 niW"o-}  
boolean bFirst = true; //是否第一次取文件 ;$gV$KB:xA  
boolean bStop = false; //停止标志 |_-w{2K  
File tmpFile; //文件下载的临时信息 o90g;Vog  
DataOutputStream output; //输出到文件的输出流 Fa v++z  
M5t.l (  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) *p#@W-:9E  
public SiteFileFetch(SiteInfoBean bean) throws IOException [^6z>  
{ ;FF+uK  
siteInfoBean = bean; y;<suGl  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #<Xq\yC51  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [m 6+I9  
if(tmpFile.exists ()) fqq4Qc)#U&  
{ hiA\~}sl n  
bFirst = false; Di4GaKa/  
read_nPos(); >w,jaQ  
} 3]9Rmx  
else ,9_O4O%  
{ wAX;)PLg  
nStartPos = new long[bean.getNSplitter()]; ">eled)O  
nEndPos = new long[bean.getNSplitter()]; !IO\g"y~|%  
} N mxh zjJ  
lcjOBu  
-qHG*v,  
j6XHH&ZEb  
} m.1-[2{8~  
J:&.[  
CYwV]lq :s  
public void run() g;6/P2w  
{ B, H9EX  
//获得文件长度 D_~;!^  
//分割文件 ]vn*eqd  
//实例FileSplitterFetch ZX1/6|_  
//启动FileSplitterFetch线程 "Y&   
//等待子线程返回 }Bsh!3D<.  
try{ #)twk `!^  
if(bFirst) X"r.*fb;N  
{ U=69q]  
nFileLength = getFileSize(); B7|%N=S%/  
if(nFileLength == -1) <j,3Dn  
{ e.%I#rNI  
System.err.println("File Length is not known!"); &ni#(   
} WG,1%=M@  
else if(nFileLength == -2) ^,AE;Z T7  
{ Q@>1z*'I  
System.err.println("File is not access!"); Iz. h  
} cg17e  
else d^!k{Qx'  
{ ?~t5>PEonv  
for(int i=0;i<nStartPos.length;i++) !k*B-@F  
{ e!gNd>b {  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); _X;,,VEV!  
} ZeU){CB  
for(int i=0;i<nEndPos.length-1;i++) wCR! bZ w  
{ ecoI-@CAI  
nEndPos = nStartPos[i+1]; 8sc2r  
} i$@xb_  
nEndPos[nEndPos.length-1] = nFileLength; jl(D;JnF  
} E QU@';~8  
} fDplYn#  
*ls6k`ymL  
x>TIx[ x  
//启动子线程 }5(_gYr  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Cb?  !+U  
for(int i=0;i<nStartPos.length;i++) h9<PP2.(  
{ X1a~l|$h  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CrL9|78  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), '/9j"mIA9$  
nStartPos,nEndPos,i); U:n~S  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); CLVT5pj='  
fileSplitterFetch.start(); _|0#  
} &dmIv[LU  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), :.]EM*p?GV  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %7aJSuQN%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", *GBV[D[G,  
nEndPos = " + nFileLength); Q[K$f%>  
// fileSplitterFetch[nPos.length-1].start(); oST)E5X;7  
i7r)9^y  
@-\=`#C**  
//等待子线程结束 xZ;eV76  
//int count = 0; <Z3C&BM  
//是否结束while循环 ~K3Lbd| r  
boolean breakWhile = false; {nUmlP=mS  
^\Q,ACkZb  
xt pY*  
while(!bStop) 1v.#ndk  
{ YtSYe%  
write_nPos(); 2\k!DF  
Utility.sleep(500); \y=28KKc:c  
breakWhile = true; l9=Ka{$^*  
;w"h n*  
bO/r1W  
for(int i=0;i<nStartPos.length;i++) (:`4*xK  
{ JU^Y27  
if(!fileSplitterFetch.bDownOver) nA(" cD[,  
{ qp6'n&^&  
breakWhile = false; H%U  
break; t`|Rn9-  
} H+Bon=$cE!  
}  =5B5  
if(breakWhile) [#Gu?L_W  
break; *K$a;2WjzG  
qg`ae  
Zn r4^i&(  
//count++; $poIWJMc  
//if(count>4) ciml:"nQ  
// siteStop(); wdBB x\FP  
} 2ns,q0I A  
BV>9U5  
l:e C+[_;>  
System.err.println("文件下载结束!"); ~zac.:a8  
} i*mU<:t  
catch(Exception e){e.printStackTrace ();} _[-MyUs  
} ),B/NZ/-  
hOZTD0  
Ezew@*(  
//获得文件长度 >"<s7$g  
public long getFileSize() w/( T  
{ (n?f016*%d  
int nFileLength = -1; !9$}1_,is  
try{ db_?da;!`  
URL url = new URL(siteInfoBean.getSSiteURL()); R0*P,~L;|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); U9b[t  
httpConnection.setRequestProperty("User-Agent","NetFox"); @^YXE,  
cRr3!<EZ  
;r"r1'a+@  
int responseCode=httpConnection.getResponseCode(); %gFIu.c  
if(responseCode>=400) l6w\E=K  
{ e#h&Xa  
processErrorCode(responseCode); P (7el  
return -2; //-2 represent access is error Qfy_@w]  
} z,m3U(  
_oBx:G6E  
Y96<c" t  
String sHeader; eF{uWus  
v+Y^mV`|  
AU`z.Isf  
for(int i=1;;i++) E8sM`2z5  
{ af>i  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); L,#YP#O,j  
//Utility.log(in.readLine()); rqN+0CT  
sHeader=httpConnection.getHeaderFieldKey(i); |z_Dw$-xm  
if(sHeader!=null) AhOBbss]q  
{ v}t{*P  
if(sHeader.equals("Content-Length")) 4+ d(d  
{ t6KKfb  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6-"tQ,AZ  
break; ;k#_/c  
} RbxQTM_:M  
} e> 9X  
else 7lwI]/ZH*  
break; ti9e(Jt!O  
} Sft vN-  
} |-\anby<  
catch(IOException e){e.printStackTrace ();} DPW^OgL;  
catch(Exception e){e.printStackTrace ();} Lc}hjK  
W9c&"T9JT  
,D`jlY-1l  
Utility.log(nFileLength); 6<S-o|Xw  
R||$Rfe  
M61Nl)|mx&  
return nFileLength; wj}LVyV  
} oP56f"BE(  
!L9|iC:8  
^vG<Ma.yk  
//保存下载信息(文件指针位置) C7m/<  
private void write_nPos() v ,h"u  
{ JP\jhkn  
try{ =d5;F`m  
output = new DataOutputStream(new FileOutputStream(tmpFile)); >T [Y>]  
output.writeInt(nStartPos.length); `fEzE\\!*  
for(int i=0;i<nStartPos.length;i++) [|*7"Q(  
{ u?SwGXi~8  
// output.writeLong(nPos); zJ8T.+qJ  
output.writeLong(fileSplitterFetch.nStartPos); dT7f yn  
output.writeLong(fileSplitterFetch.nEndPos); Wkk(6gS,  
} 3)=ix. wW  
output.close(); HX| p4-L  
} I(BJ1 8F$  
catch(IOException e){e.printStackTrace ();} wY\,b*x  
catch(Exception e){e.printStackTrace ();} dI7rx+L  
} lbovwj  
r>bgCQ#-n  
O!dS;p-F  
//读取保存的下载信息(文件指针位置)  }+/Vk  
private void read_nPos() }eZ \~2  
{ Jg'#IM  
try{ 6 .?0 {2s  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); PuZzl%i P3  
int nCount = input.readInt(); b+whZtNk7  
nStartPos = new long[nCount]; Z7y%  
nEndPos = new long[nCount]; ,Q Ge=Exn  
for(int i=0;i<nStartPos.length;i++) Kg<~Uf=1  
{ R7z @y o  
nStartPos = input.readLong(); N6_1iIM  
nEndPos = input.readLong(); SFuSM/Pf  
} Ei]Sks V>*  
input.close(); bg0ix"  
} Q-R?y+| x  
catch(IOException e){e.printStackTrace ();} Oz(=%oS  
catch(Exception e){e.printStackTrace ();} m!<FlEkN  
} X~o;jJC  
'NjeF&#6  
&DYC3*)Jih  
private void processErrorCode(int nErrorCode) ~0-)S@  
{ pl,XS6mB  
System.err.println("Error Code : " + nErrorCode); j&S.k  
} @Q ~; @M  
yG~Vvpv  
X[<#B5  
//停止文件下载 J#@+1 Nt  
public void siteStop() 8#A4B2  
{ \A\?7#9\  
bStop = true; 2,I]H'}^  
for(int i=0;i<nStartPos.length;i++) GK11fZpO:i  
fileSplitterFetch.splitterStop(); s-SFu  
Z)(#D($-  
ea$. +  
} sEw ?349Bz  
} B!)9 >  
//负责部分文件的抓取 X5+^b({  
**FileSplitterFetch.java mhU=^/X  
*/ xp3^,x;\X  
package NetFox; qPDRB.K|}  
Xs$a^zZ  
5'{QMnfB  
import java.io.*; ^e]O >CJ  
import java.net.*; #>~A-k)  
w-km qh  
^zqQ8{oV  
public class FileSplitterFetch extends Thread { c(8>oeKyD  
k:j?8o3  
`]19}GK~xo  
String sURL; //File URL HtE^7i*_  
long nStartPos; //File Snippet Start Position 438r]f?0|{  
long nEndPos; //File Snippet End Position DrBkR` a?  
int nThreadID; //Thread's ID l&W:t9o  
boolean bDownOver = false; //Downing is over A -8]4p::  
boolean bStop = false; //Stop identical r_bG+iw7p  
FileAccessI fileAccessI = null; //File Access interface 7bGt'gvv  
r0&LjH&R  
(C`nBiL<  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %t9Kc9u3p  
{ +",`Mb  
this.sURL = sURL; 16z Wm JH  
this.nStartPos = nStart; v=dN$B5y3  
this.nEndPos = nEnd; q:jv9eL.O  
nThreadID = id; @sd{V  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Ei<+{P(t0  
} _m a;b<I/<  
gLo&~|=L-  
=7:}/&  
public void run() hlc g[Qdo*  
{ %Y|AXx R  
while(nStartPos < nEndPos && !bStop) ~% ]V,-4  
{ u0[O /G  
b=WkRj  
e2nZwPH  
try{ ? )IH#kL  
URL url = new URL(sURL); |D'!.$7%  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); F$:mGyl5_  
httpConnection.setRequestProperty("User-Agent","NetFox"); Q3t%JP>;g  
String sProperty = "bytes="+nStartPos+"-"; =q"0GUei3  
httpConnection.setRequestProperty("RANGE",sProperty); }+[!h=Bx  
Utility.log(sProperty); ?"}U?m=  
0,__{?!  
slr>6o%W`  
InputStream input = httpConnection.getInputStream(); 0}k vuuR  
//logResponseHead(httpConnection); 3_eg'EP.E  
P6v@ Sn  
/<O9^hA|  
byte[] b = new byte[1024]; %>O}bdSf  
int nRead; Xpkj44cd@  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) [>j.x2=  
{ bgInIe  
nStartPos += fileAccessI.write(b,0,nRead); Ia^/^>  
//if(nThreadID == 1) )J[Ady^5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .'-t>(}v  
} [a^<2V!vMn  
[c=![ *}/  
b4ke'gx  
Utility.log("Thread " + nThreadID + " is over!"); P=9sP:[f6  
bDownOver = true; ;gRPTk$X3  
//nPos = fileAccessI.write (b,0,nRead); >u .u#de  
} #fyY37-  
catch(Exception e){e.printStackTrace ();} pFo,@M  
} $K|2k7  
} `\BBdQ#bH  
{+9t!'   
"JYWsE  
//打印回应的头信息 :c[T@[  
public void logResponseHead(HttpURLConnection con) ')fIa2dO/  
{ dsK ^-e6:5  
for(int i=1;;i++) pG/g  
{ O=1 #KNS  
String header=con.getHeaderFieldKey(i); D9r;Ys%  
if(header!=null) ^#7&R"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q| *nd!y'  
Utility.log(header+" : "+con.getHeaderField(header)); ]zvOM^l~  
else T?-K}PUcQ  
break; ; Oz p  
} fX&g. fH  
} Hu!<GB~  
B=%YD"FAv  
Q6[h;lzGV  
public void splitterStop() _9/Af1 X  
{ <g8{LG0  
bStop = true; <S@2%%W  
} ;/^O7KM-  
j8t_-sU9 i  
D6FG$SV  
} kN vNV(4  
v[m1R'  
*b1NVN$  
/* B8V85R  
**FileAccess.java 6y@o[=m  
*//文件访问(定位,写) DsiyN:o'+  
package NetFox; q1%xk =8  
import java.io.*; Sa6YqOel@  
"9H#pj -  
D4+OWbf6  
public class FileAccessI implements Serializable{ xkz`is77Y@  
X*:)]p(R  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 c5HW.3"  
RandomAccessFile oSavedFile; jATN):8W  
long nPos; 4+0:(=>[%  
B|BJkY'  
W4AFa>h  
public FileAccessI() throws IOException G9> 0w)r  
{ 5kj=Y]9\I  
this("",0); {E>(%vD  
} ;cWFh4_  
p:|p?  
rAQ3x0  
public FileAccessI(String sName,long nPos) throws IOException ^eqq|(<K  
{ #!M;4~Sfx  
oSavedFile = new RandomAccessFile(sName,"rw"); HG})V PBa  
this.nPos = nPos; _d3/="=  
oSavedFile.seek(nPos); Ml,87fo  
} Gh{vExH@5(  
2` h  
X57\sggK  
public synchronized int write(byte[] b,int nStart,int nLen) ^(yU)k3pu  
{ mv9@Az9  
int n = -1; Q<Th*t   
try{ {UEZ:a  
oSavedFile.write(b,nStart,nLen); 0-A@X>6bs  
n = nLen; ;KW}F|  
} Z <tJ+  
catch(IOException e) e_CgZ  
{ y+a]?`2  
e.printStackTrace (); EWoGdH|  
} KZTT2KsYl  
SNf*2~uq)  
z4c{W~}`  
return n; nrI-F,1  
} vC!}%sxVw_  
cH\.-5NQ  
|=4imM7  
} `Jon^&^;|  
2UjQ!g`  
0N*~"j;r#M  
/* Yf,U2A\  
**SiteInfoBean.java /=ro$@  
*/ 9mH/xP:y  
package NetFox; \P0>TWE  
M&K'5G)7  
PaYsn *{})  
public class SiteInfoBean { 5J8U] :Y)  
WMd5Y`y  
?i7}d@636  
private String sSiteURL; //Site's URL YXhxzH hPd  
private String sFilePath; //Saved File's Path `G^MTDp?L+  
private String sFileName; //Saved File's Name 8;]U:tv  
private int nSplitter; //Count of Splited Downloading File p_2-(n@  
3)+}2  
(y!<^ Q  
public SiteInfoBean() ue{0X\[P<  
{//nSplitter的缺省值为5 r%~/y  
//default value of nSplitter is 5 Kr|9??`0E  
this("","","",5); Zb=H\#T  
} pElAY3  
OfGMeN6  
z>X<Di&x)  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) BliL1"".  
{ Qyoly"b@  
sSiteURL= sURL; =E''$b?Em  
sFilePath = sPath; aI:G(C?jm  
sFileName = sName; zQQ=8#]  
this.nSplitter = nSpiltter; p$ %D  
ACcxQK}  
V/}g'_E  
} z<c@<M=Q*  
ZkZTCb`/l  
48 `k"Uy   
public String getSSiteURL() 6{p] cr  
{ c31k%/.  
return sSiteURL; (},TZ+u  
} X!%CYmIRb  
4:p+C-gs  
3jB5F0^r1  
public void setSSiteURL(String value) 2'zYrdem  
{ +5:oW~ ;  
sSiteURL = value; yY$:zc"J  
} yH0BNz8V  
3-5X^!C  
-_RMiGM?T  
public String getSFilePath() Oy^)lF/  
{ ,f;YJHEx8  
return sFilePath; :Ojsj_Z;;  
} ~]_g q;bG  
d)&}% 2ku  
Z&!5'_9{V  
public void setSFilePath(String value) S-\;f jh  
{ ')Drv)L  
sFilePath = value; rmOcA  
} 5[_|+  
'%$)"g]/#  
CG(G){u&  
public String getSFileName() bZ.q?Hlfk  
{ P<@V  
return sFileName; e-dpk^-  
} t_PAXj  
"[ 091<  
D/1f> sl  
public void setSFileName(String value) ,s*-2Sz  
{ WZ a?Xb  
sFileName = value; &cEQ6('H  
} wua`e <"  
dd +%d  
 1 U|IN=  
public int getNSplitter() k%5 o5Hx  
{ O.%' 47A  
return nSplitter; '<.@a"DnJ  
} $-zt,iRyV  
H53dy*wb$  
GoK[tjb  
public void setNSplitter(int nCount) ]YP J.[n  
{ O|opNr  
nSplitter = nCount; M7|k"iz v  
} i1"4z tZ  
} Yz?4eSa/  
4PwjG;!K  
$y\\ ?  
/* ^x8yW brE  
**Utility.java )c:i 'L  
*/ y Q_lJIX  
package NetFox; -^i[   
IXaF(2>  
MY]Z@  
public class Utility { a&3pPfC  
dVh*  a  
h7iI=[_V  
public Utility() %. =B=*  
{ Gm 0&y  
'+6SkZ  
p_x@FA(  
} nwOT%@nw  
Lc<v4Bp  
//线程睡眠 ~|_s2T  
public static void sleep(int nSecond) U8+5{,$\.  
{ qHT_,\l2  
try{ Q:6i 3 Nr/  
Thread.sleep(nSecond); aXAV`%b  
} 'rZYl Qm  
catch(Exception e) Cy'0O>v5  
{ 3]=j!_yJf  
e.printStackTrace ();  \^$g%a  
} Fc{X$hh<  
} vN`2KCl~3  
\G+ hi9T(  
//日志 FwB }@)3  
public static void log(String sMsg) <6_RWtU  
{ ^XsIQz[q  
System.err.println(sMsg); TC7Rw}jF  
} j:)"s_  
[YbnpI  
|~'PEY  
public static void log(int sMsg) hmfO\gc}y  
{ 5C}1iZEJ  
System.err.println(sMsg); ~(( '1+  
} ){u/v[O9"  
} +j*hbG=  
KCE5Z?k  
O$=[m9V  
/* i(hI\hD  
**TestMethod.java k E^%w?C  
*/ ;}iV`)S  
package NetFox; p ~/  
;7jszs.6%  
}Zs y&K  
public class TestMethod { '<}N`PS#N  
6FYO5=R  
~]CQ DR:  
public TestMethod() |\PI"rW  
{ ///xx/weblogic60b2_win.exe 381a(F[$e  
try{ Ev adY  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); P;.j5P^j`  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5cr d.1@^  
SiteFileFetch fileFetch = new SiteFileFetch(bean); 0X.(BRI~6p  
fileFetch.start(); e XB'>#&s  
} ?AMn>v  
catch(Exception e){e.printStackTrace ();} ?X'm>R. @  
2pKkg>/S  
G?p !*7N  
} p_^Jr*Mv  
= ;hz,+  
?pE)K<+Zkf  
public static void main(String[] args) g4Y1*`}2f  
{ m?Tv8-1  
new TestMethod(); C`4m#  
} %rU8^'Gu  
} ;\[n{<   
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