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http断点续传简单实现(java)

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/* 7/Lbs  
**SiteFileFetch.java u"T5m  
*/ h(/|`   
package NetFox; ] (MXP,R  
import java.io.*; 7h&xfrSrD  
import java.net.*; t ?bq ~!X  
/SMp`Q88  
S\0"G*  
public class SiteFileFetch extends Thread { :\80*[=;Z  
yr sP'th  
_9n.ir5YX  
SiteInfoBean siteInfoBean = null; //文件信息Bean BOwkC;Q[  
long[] nStartPos; //开始位置 ~Ag !wj  
long[] nEndPos; //结束位置 Q]6nW[@j'  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ?'T>/<(  
long nFileLength; //文件长度 $Fr2oSTT)  
boolean bFirst = true; //是否第一次取文件 M8juab%y  
boolean bStop = false; //停止标志 !Z=`Wk5  
File tmpFile; //文件下载的临时信息  g<,v2A  
DataOutputStream output; //输出到文件的输出流 Eq.c;3  
1Za\T?V  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) I">z#@CT  
public SiteFileFetch(SiteInfoBean bean) throws IOException AO']Kmm  
{ 5yA^n6  
siteInfoBean = bean; qsJA|z&6x  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); EiJSLL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !]kn=7  
if(tmpFile.exists ()) 5j ]}/Aq  
{ {xM%3  
bFirst = false; k(^zhET  
read_nPos(); HwU \[f  
} m7M*)N8  
else WX0@H[$i#  
{ y~- ?   
nStartPos = new long[bean.getNSplitter()]; W 8E<P y  
nEndPos = new long[bean.getNSplitter()]; |;D[Al5AMc  
} 55$by.rf?  
).ugMuk  
<EBp X   
sXhtn' <v  
} V7lDuiAI  
-q+Fj;El  
0A1l"$_|  
public void run() kN}.[enI~  
{ l>=c]  
//获得文件长度 @F,HyCSN  
//分割文件 ,YkQJ$  
//实例FileSplitterFetch /au\OBUge  
//启动FileSplitterFetch线程 HvTi^Fb\a  
//等待子线程返回 <M$hj6.tn  
try{ QT|mN  
if(bFirst) CS"p[-0  
{ %djx0sy  
nFileLength = getFileSize(); ! prU!5-  
if(nFileLength == -1) dvL'>'g  
{ C62<pLJf  
System.err.println("File Length is not known!"); .Zwn{SMtu  
} Np/[MC  
else if(nFileLength == -2) sL\|y38'  
{ pnqjAT GU  
System.err.println("File is not access!"); &rNXn?>b  
} Hy `r}+  
else |Zt=8}di  
{ jM7}LV1Ck  
for(int i=0;i<nStartPos.length;i++) + u)'  
{ (yXVp2k  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); f ~Fus  
} ^)fB "!s  
for(int i=0;i<nEndPos.length-1;i++) qA"?5j32  
{ rBny*!n  
nEndPos = nStartPos[i+1]; BR0bf5T/  
} 9s7B1Pf  
nEndPos[nEndPos.length-1] = nFileLength; =vK(-h  
} T.(SBP  
} xE)pj|  
o<g (%ncr  
Ko%rB+d  
//启动子线程 qlgh$9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; Uc6U!X  
for(int i=0;i<nStartPos.length;i++) ~Snw':  
{ qy-BZ%3  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 2XXEg> CU  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), *uv\V@0  
nStartPos,nEndPos,i); :ZzG5[o3  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ntF(K/~Y  
fileSplitterFetch.start(); EAq >v t83  
} 1gt[_P2u  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d@w I: 7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Yb6\+}th  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", qkBnEPWZy  
nEndPos = " + nFileLength); qb9%Y/xy  
// fileSplitterFetch[nPos.length-1].start(); WYh7Y  
5o72X k  
>)5vsqGZaK  
//等待子线程结束 sV*Q8b*  
//int count = 0; 3; M!]9ms  
//是否结束while循环 3$kZu  
boolean breakWhile = false; &G"]v]V  
XSxya .1  
1/fvk  
while(!bStop) -~-2 g  
{ '{+hti,Lh  
write_nPos(); K3Xy%pqR#  
Utility.sleep(500); *Z0}0< D@Z  
breakWhile = true; @+ 2Zt%  
V2y[IeSQ  
_ Po9pZ  
for(int i=0;i<nStartPos.length;i++) Ec[:6}  
{ 6@$[x* V  
if(!fileSplitterFetch.bDownOver) K{iay g!k  
{ *1%g=vb  
breakWhile = false; {Ise (>V  
break; \ agC Q&  
} TxiJ?sDh*  
} DBv5Og  
if(breakWhile) Th8Q ~*v  
break; pE`( kD  
\UC4ai2MK  
1rKR=To  
//count++; .DX#:?@4@Y  
//if(count>4) +amvQ];?Q8  
// siteStop(); awawq9)Y  
} O@$hG8:  
^Uf`w7"iY  
O7K))w  
System.err.println("文件下载结束!"); vd ;wQ  
} _AO0:&  
catch(Exception e){e.printStackTrace ();} lu{}j4  
} :#LB}=HQ  
dHu]wog  
Ltj}>.+  
//获得文件长度 l-Xxv  
public long getFileSize() RS:0xN\JN  
{ MVj@0W33m  
int nFileLength = -1; Z/I!\  
try{ eGE%c1H9a  
URL url = new URL(siteInfoBean.getSSiteURL()); hT_snb;ow  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); BNByaC  
httpConnection.setRequestProperty("User-Agent","NetFox"); f>'7~69  
=?2y <B  
c]LH.  
int responseCode=httpConnection.getResponseCode(); ZD<,h` lZ  
if(responseCode>=400) *dQRs6  
{ J\%:jg( m  
processErrorCode(responseCode); Z  b1v  
return -2; //-2 represent access is error f"tO*/|`  
} PU>;4l  
FFkG,XH  
jmb\eOq+~V  
String sHeader; 63f/-64?7  
#[si.rv->  
H z6H,h  
for(int i=1;;i++) q[#\qT&QU  
{ u1"e+4f  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 9@j~1G%^  
//Utility.log(in.readLine()); <V, ?!}V  
sHeader=httpConnection.getHeaderFieldKey(i); l&rDa=m.J  
if(sHeader!=null) [0}471  
{ 5>=tNbk"s  
if(sHeader.equals("Content-Length")) eS"gHldz  
{ Brl6r8LGi  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); EvYw$ j  
break; <Kh\i'8  
} ZJ 4"QsF  
} JC#@sJ4az)  
else YO Y+z\Q  
break; U %4g:s  
} -Z Z$ 1E  
} 06`__$@h  
catch(IOException e){e.printStackTrace ();} _(jE](,  
catch(Exception e){e.printStackTrace ();} 3UaP7p+d  
j\vK`.z  
daorKW4  
Utility.log(nFileLength); =.%ZF]Oe+#  
x B?:G  
-r2cK{Hhp&  
return nFileLength; cU>&E* wD  
} 7m jj%  
QA3l:D}u  
KZE.}8^%D  
//保存下载信息(文件指针位置) 2eK\$_b_  
private void write_nPos() y((_V%F}  
{ WY,t> 1c  
try{ @v'D9 ?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); I>xB.$A  
output.writeInt(nStartPos.length); 4"2/"D0  
for(int i=0;i<nStartPos.length;i++) c,qCZ-.Sg  
{ )k1,oUx  
// output.writeLong(nPos); \XN5))  
output.writeLong(fileSplitterFetch.nStartPos); @b/2'  
output.writeLong(fileSplitterFetch.nEndPos); `SW " RLS3  
} 2mO#vTX4  
output.close(); mx[^LaR>v  
} o`U\Nhq  
catch(IOException e){e.printStackTrace ();} VB#31T#q?  
catch(Exception e){e.printStackTrace ();} g5Vr2  
} 2%8Y-o?  
3oKGeB;Ja  
[0LqZ<\5  
//读取保存的下载信息(文件指针位置) %(Ys-GeGr  
private void read_nPos() ""+*Gn 7^8  
{ pd1m/:  
try{ Psa8OJan  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); C{Ug ?hVP  
int nCount = input.readInt(); ]Yu+M3Fq  
nStartPos = new long[nCount]; CJOl|"UyJ  
nEndPos = new long[nCount]; ]aRD6F:L  
for(int i=0;i<nStartPos.length;i++) qWpCe*C  
{ -IS9uaT5  
nStartPos = input.readLong(); O}-7 V5  
nEndPos = input.readLong(); {|h"/   
} Qzhnob#C9  
input.close(); -X[[ OR9+  
} \?^wu  
catch(IOException e){e.printStackTrace ();} PQ]9xzOg[  
catch(Exception e){e.printStackTrace ();} G7;}309s  
} EM*Or Ue  
LPn }QzH  
#<PdZl R  
private void processErrorCode(int nErrorCode) 5Nb_K`Vp*  
{ ehusI-q  
System.err.println("Error Code : " + nErrorCode); 5)7mjyo%  
} /vDF<HVzm  
S7/v ,E  
\,!q[nC  
//停止文件下载 f ti|3c  
public void siteStop() 1^#Q/J,  
{ t"p#ii a  
bStop = true; ]M(f^   
for(int i=0;i<nStartPos.length;i++) 9u@h`  
fileSplitterFetch.splitterStop(); FBAC9}V"  
} XU:DE  
kV3j}C"  
} uW~ ,H}E  
} x2sOEkcQ  
//负责部分文件的抓取 bJF/daC5  
**FileSplitterFetch.java .4W>9 8  
*/ P i!r}m  
package NetFox; )hW {>Y3x  
}.) 43(>]  
4_I{Q^f  
import java.io.*; d`<^+p)oy  
import java.net.*; =k= 2~ j  
YiuOu(X  
pf@}4PN}  
public class FileSplitterFetch extends Thread { *.c9$`s  
(I ds<n"  
K=?F3tX^  
String sURL; //File URL ]C6[`WF  
long nStartPos; //File Snippet Start Position idS RWa  
long nEndPos; //File Snippet End Position zZc@;S#  
int nThreadID; //Thread's ID Qz(T[H5%W  
boolean bDownOver = false; //Downing is over qetP93N_*  
boolean bStop = false; //Stop identical fsc~$^.~\  
FileAccessI fileAccessI = null; //File Access interface DIp:S&q2  
"ue$DyN  
#Rx"L&3Ue  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException w LN2`ucC  
{ d"6]?  
this.sURL = sURL; tW:/R@@  
this.nStartPos = nStart; N8YBu/  
this.nEndPos = nEnd; j~S!!Z ]  
nThreadID = id; KBRg95E~]l  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 ;3}EB cw)  
} H\+c'$  
5%+bWI{w  
pb6^sA%l  
public void run() `vxrC&,As  
{ kqvJ&7  
while(nStartPos < nEndPos && !bStop) P"uHtHK  
{ 8H#c4%by)  
Owpg]p yVD  
,PMb9 O\B  
try{ B/D\gjb  
URL url = new URL(sURL); ,V]A63J  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); RvSq KW8  
httpConnection.setRequestProperty("User-Agent","NetFox"); sMS9!{A  
String sProperty = "bytes="+nStartPos+"-"; Wj j2J8B  
httpConnection.setRequestProperty("RANGE",sProperty); sp Q4m  
Utility.log(sProperty); z2Y_L8u2  
W+f&%En  
@ZkAul0@  
InputStream input = httpConnection.getInputStream(); B+e_Y\B u  
//logResponseHead(httpConnection); tkN3BQ  
NC.P 2^%  
QYTTP6 Gz+  
byte[] b = new byte[1024]; yEUNkZ5^  
int nRead; PWk ?8dL-  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ]6B mCh  
{ *Qg5Z   
nStartPos += fileAccessI.write(b,0,nRead); ZE8/ m")  
//if(nThreadID == 1) &[ u6oAR  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X`3vSCn  
} B>|U-[A  
8gbm"!  
B3>Uba*-)}  
Utility.log("Thread " + nThreadID + " is over!"); \l]pe|0EW  
bDownOver = true; 'y6!%k*  
//nPos = fileAccessI.write (b,0,nRead); {y&\?'L'  
} a()6bRc~T  
catch(Exception e){e.printStackTrace ();} (' Ko#3b  
} Cl9SPz  
} ?z@v3(b[  
;o)=XEh8P  
]]uzl0LH  
//打印回应的头信息 bwSRJFqb  
public void logResponseHead(HttpURLConnection con) 5hJYy`h~  
{ @4_rxu&  
for(int i=1;;i++) =(.mf  
{ Rnj Jg?I=  
String header=con.getHeaderFieldKey(i); 5]H))}9>d  
if(header!=null) l$-=Pqb  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xxoHH#a  
Utility.log(header+" : "+con.getHeaderField(header)); ;5D @kS^  
else i.&Kpw9;m  
break; XSp x''l  
} H-_^TB  
} D/S>w(=  
M9Nk=s! 3  
qIDWl{b<  
public void splitterStop() {b|3]_-/  
{ yE.495  
bStop = true; )l#%.Z9  
}  :Hzz{'  
(:?5 i`  
GJC!0{8;  
} *(d6Z#  
8tLT'2+H#  
{=bg5I0|a  
/* ]&C:>  
**FileAccess.java YN%=Oq  
*//文件访问(定位,写) j<ABO")v  
package NetFox; %tzN@  
import java.io.*; s; B j7]  
?qg^WDs$  
s- ,=e  
public class FileAccessI implements Serializable{ h v$uH7Fz  
5u;Rr 1D  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 !,? <zg  
RandomAccessFile oSavedFile; r~$}G-g  
long nPos; 7P/?wv9+n*  
[$( sUc(%  
4_Qa=T8  
public FileAccessI() throws IOException vzY'+9q1.  
{ ]aC ':55(  
this("",0); %[]"QbF?  
} MkG`w,  
{{V ;:+62  
T-a&e9B  
public FileAccessI(String sName,long nPos) throws IOException 'Q:i&dTg  
{ cWN d<=Jp  
oSavedFile = new RandomAccessFile(sName,"rw"); MzEm*`<  
this.nPos = nPos; HGO#e  
oSavedFile.seek(nPos); !,cQ'*<W8-  
} :3KO6/+  
r{t. c?/  
IL~]m?'V(  
public synchronized int write(byte[] b,int nStart,int nLen) P0%N Q1bn  
{ n-b>m7O(  
int n = -1; k{gl^  
try{ 42rj6m\  
oSavedFile.write(b,nStart,nLen); fL ~1  
n = nLen; ?,ZELpg n  
} = EQN-{#  
catch(IOException e) w^06z,  
{ H$z>OS_6U  
e.printStackTrace (); BFBR/d[&  
} m b%C}8D  
W(;x\Nc7  
zKIGWH=qqm  
return n; !oZQ2z~  
} %04:z77  
i{o#3  
[J a)<!]<  
} _1I K$gb[  
@%6)^]m}r  
cC^W2\  
/* 9@:BK;Fi  
**SiteInfoBean.java QCeMKjCmY  
*/ H@K#|A=a  
package NetFox; 'e}uvbK  
=yl4zQmg$  
v1 LKU  
public class SiteInfoBean { `wNm%*g  
).pO2lLF4  
/8f>':zUb  
private String sSiteURL; //Site's URL an3~'g?  
private String sFilePath; //Saved File's Path AXz-4,=xX  
private String sFileName; //Saved File's Name *:a'GC%/  
private int nSplitter; //Count of Splited Downloading File %lN2n,AK  
!\QeBd+  
wk" l[cH>  
public SiteInfoBean() 3(1 ]FKZtt  
{//nSplitter的缺省值为5 b6 $,Xh  
//default value of nSplitter is 5 T!MZ+Ph`F  
this("","","",5); d; 9*l!CF  
} iJFr4o/R  
hT?6sWa  
a "R7JjH  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %1Yz'AiW[  
{ oFWt(r   
sSiteURL= sURL; +`ai1-vw  
sFilePath = sPath; 59V#FWe-  
sFileName = sName; OkLz^R?d  
this.nSplitter = nSpiltter; 3)}(M  
W%TQYR  
+wipfL~&S  
} 538fK9[  
:*^:T_U  
Vzpt(_><  
public String getSSiteURL() 59.$ULQVMY  
{ X4a^m w\"  
return sSiteURL; }i(qt&U;  
} 5?Bc Y ;  
2z4<N2! M  
'!p=aF9L  
public void setSSiteURL(String value) grr'd+_e  
{ aS el* L  
sSiteURL = value; aYqm0HCT  
} :pRF*^eU  
+#4]o }6G  
tv0Ha A  
public String getSFilePath() T=WNBqKo]  
{ UH[<&v  
return sFilePath; uKv&7p@|_)  
} aR _NyA  
qP7G[%=v  
WJfES2N  
public void setSFilePath(String value) 2UiR~P]%  
{ ~/2g)IS  
sFilePath = value; {;*}WPYb  
} ]bm=LA  
"f4<B-9<$  
a5|@R<iF  
public String getSFileName() f-4.WW2FN  
{ P|N2R5(>T  
return sFileName; Jy]Id*u9  
} 6JhMkB^h  
@D)Z{=>{=5  
L7]]ZAH!1  
public void setSFileName(String value) uMvb-8  
{ g5i#YW  
sFileName = value; []zua14F6  
} [>f]@>  
6gnbkpYi  
&f-hG3/M  
public int getNSplitter() ND5$bq Nu?  
{ \@K~L4>  
return nSplitter; gw^'{b  
} T?n -x?e  
WWNu:,  
kx:jI^  
public void setNSplitter(int nCount) ?R|th Z  
{ VevNG *  
nSplitter = nCount; =s;M]:  
} 4J5pXlzV  
} FbAW_Am(  
<C'Z H'p  
v`x|]-/M&  
/* :'}@Al9=>  
**Utility.java 'Dath>Y=  
*/ }$&xTW_  
package NetFox; 6V1:qp/6  
aE)by-'  
z\TLsx  
public class Utility { ^z~~VBv  
+6l]]*H  
L[y Pjw:0  
public Utility() )#C mQXgG  
{ RF?DtNuq  
L&kr{7q  
CE ~@}`  
} _okWQvdH  
(?>cn_m  
//线程睡眠 9pL g+6O  
public static void sleep(int nSecond) ~jN'J+_$  
{ eh(<m8I  
try{ sZg6@s=  
Thread.sleep(nSecond); ;JT(3yK4>p  
} 7&U&E|  
catch(Exception e) 6S1m<aH6  
{ _Zc4=c,K  
e.printStackTrace (); O,s.D,S  
} P|xG\3@Z  
} .TpsJXF  
M:n6BC>t"  
//日志 ~Y7dH Dn  
public static void log(String sMsg) S_ b/DO  
{ Xj@+{uvQB  
System.err.println(sMsg); `)K y0&?  
} 0 )}$^TV  
X(*!2uS  
L(G92,.  
public static void log(int sMsg) TTZe$>f  
{ ~aTKG|74  
System.err.println(sMsg); <jA105U"m>  
} tU@zhGb  
} "35A/V  
]*N1t>fb  
Udgqkl  
/* ,SUT~oETP  
**TestMethod.java )d`mvZBn1  
*/ Da.G4,vLh  
package NetFox; -SCM:j%h  
~F!,PM/  
H:QhrL+7_  
public class TestMethod { V '.a)6  
*if`/N-q(m  
C vDxq:x  
public TestMethod() Bp?  
{ ///xx/weblogic60b2_win.exe &7>zURv  
try{ 56}X/u  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [ f/I2  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); F<|t\KOW  
SiteFileFetch fileFetch = new SiteFileFetch(bean); B^v8,;jZT  
fileFetch.start(); 8sOQ9  
} O;uG?.\  
catch(Exception e){e.printStackTrace ();} `]i []|  
%*}Y6tl'|  
"ju'UOcS/  
} iE].&>w  
0~Gle:  
WFTvOFj  
public static void main(String[] args) Fc6iQ  
{ 'b&yrBFD  
new TestMethod(); g>JLDQdc  
} ;i<jhNA  
} ";SiL{Z  
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