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http断点续传简单实现(java)

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/*  y\F=ui  
**SiteFileFetch.java sLcFt1  
*/ R 4wr  
package NetFox; +jqj6O@Tjr  
import java.io.*;  jAND7&W  
import java.net.*; t=R6mjb  
]bgY6@M  
}E}8_ 8T6  
public class SiteFileFetch extends Thread { Y& ] 8 {  
?G08NR  
{^Pq\h;  
SiteInfoBean siteInfoBean = null; //文件信息Bean x3e]d$  
long[] nStartPos; //开始位置 RiO="tX'  
long[] nEndPos; //结束位置 gcJF`H/iNK  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -@IL"U6  
long nFileLength; //文件长度 eX2<}'W<  
boolean bFirst = true; //是否第一次取文件 d'l$$%zJ  
boolean bStop = false; //停止标志 Iia.k'N  
File tmpFile; //文件下载的临时信息 CiL94Nkd9  
DataOutputStream output; //输出到文件的输出流 !RlC~^ -  
M8@_Uj  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 5M23/= N  
public SiteFileFetch(SiteInfoBean bean) throws IOException cgj.e  
{ s(&;q4|  
siteInfoBean = bean; #vf_D?^  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l #@&~f[  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); p8,0lo  
if(tmpFile.exists ()) cX At :m  
{ 1Qh`6Ya f  
bFirst = false; /.=r>a }l  
read_nPos(); 2 [!Mx&^  
} &!y]:CC{  
else kDB iBNdB  
{ {$^SP7qV#>  
nStartPos = new long[bean.getNSplitter()]; !Zbesp KZ  
nEndPos = new long[bean.getNSplitter()]; -)<m S  
} 2 Y|D'^  
,vG<*|pn  
hN(L@0)  
'5};M)w  
} 3D)b*fPc  
.dI)R40L/\  
?Ay3u^X  
public void run() (Q-I8Y8l8  
{ qi+&|80T.  
//获得文件长度 mjEs5XCC"  
//分割文件 vv 7+ >%  
//实例FileSplitterFetch o6?l/nJ  
//启动FileSplitterFetch线程 2[dIOb4b  
//等待子线程返回 g]`bnZ7  
try{ FBsn;,3<W  
if(bFirst) /qxJgoa  
{ ,.g}W~S)  
nFileLength = getFileSize(); H2Eb\v`#  
if(nFileLength == -1) gKL1c{BV  
{ [xpQH?  
System.err.println("File Length is not known!"); +zRh fIJHH  
} %{STz  
else if(nFileLength == -2) #@Ujx_F  
{ B#tdLv"I  
System.err.println("File is not access!"); =s'7$D}0.  
} Isovwd  
else D{AFL.r{  
{ " OGdE_E  
for(int i=0;i<nStartPos.length;i++) IM ad$AKc  
{ d.pp3D 9/  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Q @2(aR  
} A/Khk2-:  
for(int i=0;i<nEndPos.length-1;i++) wO"GtVd  
{ =w <VT%  
nEndPos = nStartPos[i+1]; fW~*6ln  
} *?8RXer  
nEndPos[nEndPos.length-1] = nFileLength; )&.!3y 660  
} abZdGnc  
} (5;D7zdA  
/R%^rz'w  
V:\]cGA{  
//启动子线程 8Inx/>eOI  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 0yHjrxc$  
for(int i=0;i<nStartPos.length;i++) 5 R*lVUix  
{ h#{T}[  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 93I'cWN  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 55hyV{L%  
nStartPos,nEndPos,i); IT1P Pm  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nC~fvyd<P  
fileSplitterFetch.start(); } gkP  
} b%nkIPA  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ] C,1%(  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 6wpU6NU  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", b}%g}L D  
nEndPos = " + nFileLength); >Me]m<$E;  
// fileSplitterFetch[nPos.length-1].start(); B~_Spp  
>Zdi5') 5  
dYyW]nZ&  
//等待子线程结束 ~Oh=   
//int count = 0; {NeWdC  
//是否结束while循环 l.7d$8'\  
boolean breakWhile = false; IIax gfhZ  
5w-JPjH  
zKJ. Tj W  
while(!bStop) ih!~G5Xi9i  
{ 4zzlazU  
write_nPos(); E0`[G]*G  
Utility.sleep(500); MW]8;`|jC  
breakWhile = true; Xb+3Xn0}&8  
(zmNa}-  
{{E jMBg{  
for(int i=0;i<nStartPos.length;i++) kr{)  
{ M;qb7Mu  
if(!fileSplitterFetch.bDownOver) x(vai1CrdH  
{ tE:X,Lt[  
breakWhile = false; vpafru4  
break; WFj*nS^~l  
} DoG%T(M!a9  
}  ,F}r@  
if(breakWhile) P/`m3aSzX.  
break; "!a`ygqpT  
+@>:%yX  
Tc,$TCF  
//count++; }3sN+4  
//if(count>4) gV.f*E1C  
// siteStop(); 3"vRK5Bf  
} &>V/X{>$`K  
!3HsI| $<G  
F8 ?uQP8  
System.err.println("文件下载结束!"); (!ZV9S  
} ?C~X@sq  
catch(Exception e){e.printStackTrace ();} #|ddyCg2  
} cdN/Qy  
!Y|8z\ Q  
fPrb%  
//获得文件长度 Ivjw<XP6K  
public long getFileSize() IwM8#6;S~  
{ _iq2([BpL  
int nFileLength = -1; JE9>8+  
try{ wlL8X7+:  
URL url = new URL(siteInfoBean.getSSiteURL()); 0`Gai2\1@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); R|H[lbw  
httpConnection.setRequestProperty("User-Agent","NetFox"); = uk`pj  
Me<du& T  
\KN dZC?V2  
int responseCode=httpConnection.getResponseCode(); r!~(R+,c  
if(responseCode>=400) rV~T>x  
{ `11#J;[@G  
processErrorCode(responseCode); wH#-mu#Yl<  
return -2; //-2 represent access is error Tr$i= M  
} g#Mv&tU  
jPpRsw>  
eB7>t@ED  
String sHeader; & L3UlL  
t5n2eOy~T  
[5!'ykZ  
for(int i=1;;i++) Kny%QBoiw  
{ fZ{&dslg  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); <g*.p@o  
//Utility.log(in.readLine()); 6I5o2i  
sHeader=httpConnection.getHeaderFieldKey(i); OFIMi^@  
if(sHeader!=null) %Dra7B%  
{ n3*UgNg%fK  
if(sHeader.equals("Content-Length")) ;n` $+g:>  
{ pY, O_ t$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ?-d Ain1w  
break; e"PMvQ  
} srsK:%`  
} @7 )Z  
else u2\+?`Ox  
break;  :4{Qh  
} v8>!Gft  
} o|0 '0P  
catch(IOException e){e.printStackTrace ();} Vk WO}  
catch(Exception e){e.printStackTrace ();} ]u;GNz}?  
90?,-6  
V8\$`NEP  
Utility.log(nFileLength); tnN'V  
(lieiye^  
mZ~mf->%  
return nFileLength; 2|$lk8/,  
} )>?! xx_`  
-`Da`ml  
A"0wvk)UcY  
//保存下载信息(文件指针位置) J &{qppN  
private void write_nPos() _IC,9bbg  
{ 'xQna+%h  
try{ @T5YsX]qb7  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sE-x"c  
output.writeInt(nStartPos.length); xcw%RUC-  
for(int i=0;i<nStartPos.length;i++) 9^(HXH_f  
{ Y:rJK|m  
// output.writeLong(nPos); NoJUx['6  
output.writeLong(fileSplitterFetch.nStartPos); I Jqv w  
output.writeLong(fileSplitterFetch.nEndPos); 692Rw}/  
} P$6W`^D Z  
output.close(); 2rF?Q?$,B  
} 4|FRg  
catch(IOException e){e.printStackTrace ();} NP$e-" 1  
catch(Exception e){e.printStackTrace ();} *&(2`#C;  
} @X K>  
1 pa*T!  
nG!&u1*  
//读取保存的下载信息(文件指针位置) KlY,NSlQ  
private void read_nPos() #NW Zk.S  
{ O >nK ,.  
try{ ZGA)r0] P`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); FwXKRZa  
int nCount = input.readInt(); T!Xm")d  
nStartPos = new long[nCount]; 1]_?$)$T  
nEndPos = new long[nCount]; <"hb#Tn  
for(int i=0;i<nStartPos.length;i++)  <V7SSm  
{ j.<:00<  
nStartPos = input.readLong(); MRjH40" 2  
nEndPos = input.readLong(); +{5JDyh0  
} 1XqIPiXJ  
input.close(); A<mj8qz  
} o`b$^hv{A  
catch(IOException e){e.printStackTrace ();} 1d/NZJ9  
catch(Exception e){e.printStackTrace ();} Po'-z<}wS  
} +ylxezc  
xOwNCh  
tCuN?_ UG  
private void processErrorCode(int nErrorCode) 3w t:5 Im  
{ umZlIH[7  
System.err.println("Error Code : " + nErrorCode); P4hZB_.=  
} di"C]" ;  
Tld1P69(  
P{"  WlJ  
//停止文件下载 0[V&8\S~'T  
public void siteStop() &7$,<9.  
{ D/gd  
bStop = true; kuWK/6l4  
for(int i=0;i<nStartPos.length;i++) IRlN++I!  
fileSplitterFetch.splitterStop(); 6e-#XCR{  
FYp|oD2=1  
gsLr=  
} jK\V|5k  
} "}0)YRz%  
//负责部分文件的抓取 +R2^* *<  
**FileSplitterFetch.java a];BW)  
*/ cSY2#u|v  
package NetFox; F9Ifw><XM  
mGt\7&`  
[u/zrpTk  
import java.io.*; kyy0&L  
import java.net.*; }l,T~Pjb  
}5fU7&jA;3  
0|.7Kz^  
public class FileSplitterFetch extends Thread { 6W)xj6<@  
*eHA: A_I  
J ZVr&KZN  
String sURL; //File URL U(rr vNt:t  
long nStartPos; //File Snippet Start Position Ix*BI9E  
long nEndPos; //File Snippet End Position -@YVe:$%b  
int nThreadID; //Thread's ID V<7R_}^_7  
boolean bDownOver = false; //Downing is over zj~8>QnKk  
boolean bStop = false; //Stop identical Zx}N Fcn  
FileAccessI fileAccessI = null; //File Access interface Gojl0?  
x?%rx}h  
:hC {5!|  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException v9Z lNA7m!  
{ 1 ;_{US5FR  
this.sURL = sURL; g,00'z_D  
this.nStartPos = nStart; B`g<Ge~  
this.nEndPos = nEnd; Q mb[ e>  
nThreadID = id; Rf)'HT  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 S1D9AcK  
} DCEvr"(  
T)b3N| ONB  
iifc;62  
public void run() a"`g"ZRx  
{ ) 1lJ<g#  
while(nStartPos < nEndPos && !bStop) /W"Bf  
{ s5c! ^,L8  
(Wm/$P;  
d%}crM-KTL  
try{ r4;5b s6wm  
URL url = new URL(sURL); ^m6k@VM  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Gl?P.BCW.&  
httpConnection.setRequestProperty("User-Agent","NetFox"); k)H[XpM  
String sProperty = "bytes="+nStartPos+"-"; v+xgxQGYH  
httpConnection.setRequestProperty("RANGE",sProperty); anHBy SI3  
Utility.log(sProperty); hKk\Y{wv'  
*23m-  
1_Dn?G^H  
InputStream input = httpConnection.getInputStream(); 7sQ]w   
//logResponseHead(httpConnection); /Nj:!! AN  
S[W9G)KWp  
LP5eFl`|T  
byte[] b = new byte[1024]; S1}1"y/  
int nRead; qPFG+~\c  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) 5?V?  
{ lH#@^i|G  
nStartPos += fileAccessI.write(b,0,nRead); 5;3c<  
//if(nThreadID == 1) "/4s8.dw+u  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 3e!3.$4M  
} Nw9-pQ  
|@o]X?^  
6Nfof  
Utility.log("Thread " + nThreadID + " is over!"); rK(x4]I l"  
bDownOver = true; 8w{#R{w  
//nPos = fileAccessI.write (b,0,nRead); d8Q_6(Ar|  
} XBfiaj  
catch(Exception e){e.printStackTrace ();} ,W)IVc   
} q|47;bK'  
} z;fd#N:  
l }2%?d  
%\(y8QV  
//打印回应的头信息 {Y3_I\H8{  
public void logResponseHead(HttpURLConnection con) veYsctK~  
{ % +kT  
for(int i=1;;i++) 37:b D  
{ .LXh]I *  
String header=con.getHeaderFieldKey(i); %{N$1ht^  
if(header!=null) ch5`fm  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); H6%!v1 u  
Utility.log(header+" : "+con.getHeaderField(header)); R,d70w (_  
else %=NM_5a}]  
break; ooLnJ Y#  
} `}k&HRn  
} #a7Amh\nT  
} #\;np  
E<zT  
public void splitterStop() v@$evmA  
{ b*'=W"%\  
bStop = true; !LHzY(  
} zCBtD_@  
y~]I Vl"  
C>w9 {h  
} 1K? & J2  
!^>LOH>j  
LH3N}J({  
/* }%o+1 <=  
**FileAccess.java c:?#zX  
*//文件访问(定位,写) %vf2||a$BS  
package NetFox; v GR \GFm  
import java.io.*; 6mI_Q2  
wZ]BY;  
RB lOTQjv  
public class FileAccessI implements Serializable{ 5I8FD".i  
[x$eF~Kp  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -CU7u=*b  
RandomAccessFile oSavedFile; A]tf>H#1  
long nPos; eZR8<Z %  
>?G|Yz*kEJ  
F653[[eQ  
public FileAccessI() throws IOException N#pl mPrZ  
{ P xP?hk  
this("",0); rx}ujjx  
} N1s $3Ul  
\4\\575zp'  
c5B_WqjJ  
public FileAccessI(String sName,long nPos) throws IOException gq/ePSa  
{ ,IT)zCpaBP  
oSavedFile = new RandomAccessFile(sName,"rw"); #U!(I#^3  
this.nPos = nPos; Kbz7  
oSavedFile.seek(nPos); @ V7ooo!  
} Z5*(W;;  
}GoOE=rhY  
P[#WHbn  
public synchronized int write(byte[] b,int nStart,int nLen) qOcG|UgF  
{ aV?}+Y{#  
int n = -1; skR, M=F~  
try{ 9aF..  
oSavedFile.write(b,nStart,nLen); :bM$;  
n = nLen; /v bO/Mr  
} RXx?/\~yd;  
catch(IOException e) qa0JQ_?o]  
{ F)E7(Un`8  
e.printStackTrace (); 0'q(XB`i=  
} H%01&u  
vHI"C %  
Z+``/Q]>+  
return n; FQ9csUjpB  
} NqQ(X'W7  
Hz3 S^o7  
$@u^Jt, ?  
} PFDWC3<  
t5X^(@q4N  
CJ}@R.Zy  
/* /4"S}P>f  
**SiteInfoBean.java xPfnyAo?%z  
*/ O&?CoA?  
package NetFox; \6`%NhkM_  
?2<6#>(7a  
F;MT4*4  
public class SiteInfoBean { <_sT]?N #  
cP#]n)<  
8Snq75Q<   
private String sSiteURL; //Site's URL )HzITsFZKT  
private String sFilePath; //Saved File's Path ek{PA!9Sk  
private String sFileName; //Saved File's Name 2,XqslB)  
private int nSplitter; //Count of Splited Downloading File ]:E! i^C`Z  
?CUp&L0-"  
:S+U}Sm[  
public SiteInfoBean() ?^yh5   
{//nSplitter的缺省值为5 uu@'02G8  
//default value of nSplitter is 5 G8(i).Q  
this("","","",5); d WB8  
} !(ux.T0  
>D p6@%  
X^ ^?}>t[  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 1&@wb'MBs.  
{ "mP*}VF  
sSiteURL= sURL; p=`x  
sFilePath = sPath; hml\^I8Q>F  
sFileName = sName; i3kI2\bd/  
this.nSplitter = nSpiltter; #Rm=Em}d  
L$TKO,T  
p\]LEP\z,  
} DO-K  
Ji}IV  
(y+5d00  
public String getSSiteURL() li_pM!dWU_  
{ [>J~M!yu:r  
return sSiteURL; {ZsWZJ!  
} 8F\Msx  
Acq>M^E3  
^0ZKHR(}e  
public void setSSiteURL(String value) j=jrzG+`  
{ E'BH7JV  
sSiteURL = value; _@~kYz  
} FUqhSW  
<C.$Db&9  
RkH oT^  
public String getSFilePath() f\F_?s)_y  
{ ?9r,Y;,H  
return sFilePath; G}dOx}kT  
} Lq $4.l[j  
2W:?#h3  
}b ]y 0"  
public void setSFilePath(String value) kJ<Xq   
{ f/[?5M[  
sFilePath = value; 8apKp?~yW  
} Uo[5V|>X6  
hzPB~obC  
v!RB(T3  
public String getSFileName() .McoW7|Y  
{ l6DIsR  
return sFileName; *6x^w%=A  
} Z Lio8  
;pNbKf:  
]I' xLh`  
public void setSFileName(String value) cA*X$j6  
{ q(PT'z  
sFileName = value; >A(?Pn{|a  
} dZiWVa  
u*-<5& X  
;!Z7-OZX  
public int getNSplitter() o` 1V  
{ CT:eV7<>s  
return nSplitter; m6Cd^'J9^  
} E~@HC5.M  
l0_E9qh-i  
U;Y}2  
public void setNSplitter(int nCount) >5vl{{,$K  
{ er7/BE&  
nSplitter = nCount; 09;'z  
} tG ^?fc  
} ]-Y]Q%A4  
FQ~ead36C  
iN/!k.ybW}  
/* [BR}4(7  
**Utility.java RJs G]`  
*/ f, j(uP  
package NetFox; u-M$45vct  
)E~\H+FP6  
;3?J#e6;  
public class Utility { "JLhOTPaHf  
W;g+R-  
5<BV\'  
public Utility() E4aCGg  
{ f{5| }PL  
SU}oKii /  
V #\ZS{'J  
} iGeT^!N  
W!0  
//线程睡眠 bOIM0<(h  
public static void sleep(int nSecond) ,Yprk%JT  
{ Eno2<<  
try{ CU^3L|f2N  
Thread.sleep(nSecond); @C [|'[xQ  
} ,~?A. 5  
catch(Exception e) \C2P{q/m  
{ {,C8}8 a W  
e.printStackTrace (); % ih7Jt  
} #`)-$vUv^f  
} hRZS6" #  
-%gd')@SfD  
//日志 nC{rs+P  
public static void log(String sMsg) /z?7ic0  
{ M"l rwun^  
System.err.println(sMsg); oUKbzr/C  
} F`V[G(f+r  
qg:I+"u  
4e\`zy  
public static void log(int sMsg) Fl3r!a!P,  
{ d47:2Zj  
System.err.println(sMsg); '2J6%Gg  
} QV7c9)<]'}  
} o@`E.4  
_@;3$eB  
'{k Nbx51  
/* YeVc,B'  
**TestMethod.java ~ 2oP,  
*/ : It W|  
package NetFox; 2bxMIr  
H;Qn?^  
q]%bd[zkz  
public class TestMethod { QuRg(K%:  
^(JbJ@m/  
Fj('l  
public TestMethod() jz7ltoP  
{ ///xx/weblogic60b2_win.exe <Jrb"H[ T"  
try{ u#,'ys  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); w:xKgng=L  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +4nR&1z$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); .EZ{d  
fileFetch.start(); D#[ :NXahn  
} (E(:F[.S  
catch(Exception e){e.printStackTrace ();} j/mp.'P1k  
FY}*Z=D%  
yB{o_1tc  
} tskODM0Zf  
&b")`p&K  
B(Q.a&w45t  
public static void main(String[] args) ]3u'Qv}o  
{ !!O{ ppM  
new TestMethod(); UKQ&TV}0  
} 2.2a2.I1  
} 3C[4!>|  
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