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http断点续传简单实现(java)

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/* d9f C<Tp  
**SiteFileFetch.java x:NY\._  
*/ S]e|"n~@  
package NetFox; mP~QWx![N  
import java.io.*; WdH$JTk1  
import java.net.*; ;>EM[u  
{tuYs:  
#4Rx]zW^%  
public class SiteFileFetch extends Thread { 1QcNp (MO  
NdA[C|_8}f  
~F|+o}a `  
SiteInfoBean siteInfoBean = null; //文件信息Bean y1eW pPJa  
long[] nStartPos; //开始位置 3</_c1~  
long[] nEndPos; //结束位置 'j8:vq^d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 u"cV%(#  
long nFileLength; //文件长度 *eTqVG.  
boolean bFirst = true; //是否第一次取文件 58tARLDr  
boolean bStop = false; //停止标志 *k(XW_>  
File tmpFile; //文件下载的临时信息 y*jp79G  
DataOutputStream output; //输出到文件的输出流 jjB~G^n  
taHJ ub  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) vAF "n  
public SiteFileFetch(SiteInfoBean bean) throws IOException ,F8Yn5h  
{ K( c\wr\6  
siteInfoBean = bean; ;40/yl3r3[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Fx_z6a  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); r"3=44St  
if(tmpFile.exists ()) |PCm01NU!  
{ )np:lL$$  
bFirst = false; :1. L}4"gg  
read_nPos(); shy-Gu&  
} 36&e.3/#  
else B:yGS*.tu  
{ ;s= l52  
nStartPos = new long[bean.getNSplitter()]; i4Q@K,$  
nEndPos = new long[bean.getNSplitter()]; O'p9u@kc  
} I#Y22&G1  
E1aHKjLQ  
O_ muD\  
6EoMt@7g  
} W dK #ZOR  
?DS@e@lx  
r ,8 [O  
public void run() 5FPM`hLT  
{ B?gOHG*vd>  
//获得文件长度 MO]F1E?X  
//分割文件 JQ_sUYh~3  
//实例FileSplitterFetch +;(c:@>@,  
//启动FileSplitterFetch线程  twHVv  
//等待子线程返回 ,hm\   
try{ X6w6%fzOH>  
if(bFirst) I3{PZhU.  
{ CAig ]=2'  
nFileLength = getFileSize(); :S{BbQ){]  
if(nFileLength == -1) !OhC/f(GBZ  
{ R6<X%*&%  
System.err.println("File Length is not known!"); }z'8Bu  
} D :4[ ~A  
else if(nFileLength == -2) 1APe=tJ  
{ Fbr;{T .  
System.err.println("File is not access!"); 8+Lm's=W*  
} ~f&E7su-6+  
else ;LKkbT 5  
{ xf\C|@i  
for(int i=0;i<nStartPos.length;i++) J\} twYty  
{ Fo (fWvz  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); hlvK5Z   
} &.)^ %Tp\z  
for(int i=0;i<nEndPos.length-1;i++) >;aWz%-  
{ z3{G9Np  
nEndPos = nStartPos[i+1]; n:I,PS0H<  
} wv>^0\o  
nEndPos[nEndPos.length-1] = nFileLength; htO +z7  
} ,a{P4Bq  
} ;IvY^(YS@;  
7J D' )  
?8H8O %Z8  
//启动子线程 ?um;s-x)  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]!W=^!  
for(int i=0;i<nStartPos.length;i++) ihhDOmUto  
{ %OL$57Ia  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ^&9zw\x;z  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), Hs;4lSyUO  
nStartPos,nEndPos,i); ^  glri$m  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %vn"{3y>rF  
fileSplitterFetch.start(); p;`>e>$  
} j1Y~_  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), L Tm2G4+]  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); !,_u)4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", hIYNhZv  
nEndPos = " + nFileLength); y1jCg%'H  
// fileSplitterFetch[nPos.length-1].start(); )W,aN)1)  
5zK4Fraf  
@(EAq<5{  
//等待子线程结束 1SQ3-WU s  
//int count = 0; h6L&\~pf  
//是否结束while循环 t4."/ .=+  
boolean breakWhile = false; 9R!atPz9  
1 fp?  
F$y$'Rzu_B  
while(!bStop) NR$3%0 nC6  
{ W 8<&gh+  
write_nPos(); Co9^OF-k  
Utility.sleep(500); H5/6TX72N  
breakWhile = true; ]#i igPZ7  
@o].He@L<j  
B-RjMxX4>  
for(int i=0;i<nStartPos.length;i++) `P@<3]  
{ Y,qI@n<  
if(!fileSplitterFetch.bDownOver) hk;5w{t}}  
{ v4a8}G  
breakWhile = false; E<rp7~#  
break; ; }I:\P  
} |MTnH/|  
} 2"v6 >b%  
if(breakWhile) >>4qJ%bL  
break; sU<Wnz\[  
}`@vF|2L  
M5 LfRBO  
//count++; ~gJwW+  
//if(count>4) [Q~#82hBhY  
// siteStop();  C#.->\  
} do hA0  
#H&|*lr  
xJpA0_xfG  
System.err.println("文件下载结束!"); pHGYQ;:L  
} C$=%!wf  
catch(Exception e){e.printStackTrace ();} ]6,\r"  
} O0x,lq  
SBu"3ym  
4!{KWL`A  
//获得文件长度 Ot0ap$&  
public long getFileSize() n1ZbRV  
{ (!u~CZ;  
int nFileLength = -1; ^cC,.Fdw  
try{ ^ 'MT0j  
URL url = new URL(siteInfoBean.getSSiteURL()); c1(RuP:S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .|KyNBn  
httpConnection.setRequestProperty("User-Agent","NetFox"); BiLY(1,  
kM l+yli3c  
(Bb5?fw  
int responseCode=httpConnection.getResponseCode(); EmWn%eMN  
if(responseCode>=400) 6D;Sgc5"  
{ G6Axs1a  
processErrorCode(responseCode); fivw~z|[@  
return -2; //-2 represent access is error zy?|ODM  
} 3)wN))VBX  
b<[Or^X ]  
*uRBzO}  
String sHeader; k!j5tsiR  
)b L'[h  
0@0w+&*"@  
for(int i=1;;i++) dmtr*pM_  
{ =osk+uzzG  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); tPWLg),  
//Utility.log(in.readLine()); & GO}|W  
sHeader=httpConnection.getHeaderFieldKey(i); jxJ8(sr$  
if(sHeader!=null) >{n,L6_ t  
{ ,$L4dF3  
if(sHeader.equals("Content-Length")) IxN9&xa  
{ |)th1 UH  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *\a4wZ6<3  
break; ah$b [\#C  
} un"Gozmt5  
} bn&TF3b  
else "m$##X\  
break; IZ-1c1   
} tyDU @M  
} h|9L5  
catch(IOException e){e.printStackTrace ();}  R Z?jJm$  
catch(Exception e){e.printStackTrace ();} nIf1sH>  
8P\G }  
Pl06:g2I  
Utility.log(nFileLength); se2!N:|R!G  
bjW]bRw  
V*;(kEqj  
return nFileLength; GT.,  
} np^N8$i:n  
ea2ayT  
r EE1sy/#  
//保存下载信息(文件指针位置) K=Z|/Kkh  
private void write_nPos() )gUR@V>e2  
{ %g$o/A$  
try{ \A#41  
output = new DataOutputStream(new FileOutputStream(tmpFile)); {%5eMyF#  
output.writeInt(nStartPos.length); ?3`UbN:  
for(int i=0;i<nStartPos.length;i++) :K,i\  
{ T@B/xAq5!  
// output.writeLong(nPos); /N10  
output.writeLong(fileSplitterFetch.nStartPos); k/_ 59@)  
output.writeLong(fileSplitterFetch.nEndPos); dh iuI|?@  
} E?f-wQF  
output.close(); l}|%5.5-  
} 9!\B6=r y4  
catch(IOException e){e.printStackTrace ();} !X#OOqPr=  
catch(Exception e){e.printStackTrace ();} OX7M8cmc+  
} Yx%Hs5}8  
a$OE0zn`  
X=&ET)8-Y  
//读取保存的下载信息(文件指针位置) e2TiBTbQaF  
private void read_nPos() 9d659i C  
{ ^98~U\ar  
try{ Tn e4  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); wH&!W~M  
int nCount = input.readInt(); ORw,)l  
nStartPos = new long[nCount]; DU'`ewLL7  
nEndPos = new long[nCount]; CAWNDl4  
for(int i=0;i<nStartPos.length;i++) BoWg0*5xb  
{ (k.[GfCbD  
nStartPos = input.readLong(); 1N-\j0au  
nEndPos = input.readLong(); `5.'_3  
} z'n:@E  
input.close(); ql{ OETn#  
} |v%YQ R  
catch(IOException e){e.printStackTrace ();} %)W2H^  
catch(Exception e){e.printStackTrace ();} &)ChQZA  
} :Yh+>c}N  
UKvWJnz  
g-bK|6?yz  
private void processErrorCode(int nErrorCode) 4N3R|  
{ j{A y\n(  
System.err.println("Error Code : " + nErrorCode); $k%2J9O  
} 7(8;t o6(  
%s|Ely)  
X`>i& I]  
//停止文件下载 E6ElNgL  
public void siteStop() cp7=epho  
{ n M*%o-  
bStop = true; }2.`N%[  
for(int i=0;i<nStartPos.length;i++) /nNN,hz  
fileSplitterFetch.splitterStop(); J=I:CD%  
PiIpnoM  
Vn}0}Jz  
} K7:)nv E  
} -;m0R  
//负责部分文件的抓取 )9`qG:b'  
**FileSplitterFetch.java l<LI7Z]A  
*/ AJ`h9 %B  
package NetFox; ;:g@zAV  
'Aq{UGN  
06Sceq  
import java.io.*; v%z=ysA  
import java.net.*; ]Ie 0S~  
J @1!Oq>  
[D4SW#  
public class FileSplitterFetch extends Thread { }rw8PZ9  
6j]0R*B7`Q  
]MitOkX  
String sURL; //File URL g7`LEF <A  
long nStartPos; //File Snippet Start Position  w``ST  
long nEndPos; //File Snippet End Position <)c)%'v  
int nThreadID; //Thread's ID 9IfmW^0  
boolean bDownOver = false; //Downing is over ~KX/ Ai  
boolean bStop = false; //Stop identical ??vLUv  
FileAccessI fileAccessI = null; //File Access interface &.Qrs :U  
'XjZ_ng  
dOH &  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException k2tF}  
{ @9RM9zK.q  
this.sURL = sURL; )lqAD+9Q  
this.nStartPos = nStart; #a,PZDaE  
this.nEndPos = nEnd; bJ {'<J  
nThreadID = id; 9 -a0:bP  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '$(^W@M#6  
} E]n&=\  
H3=qe I  
s)D;a-F  
public void run() +_oJ}KI  
{ h]}wp;Z  
while(nStartPos < nEndPos && !bStop) j-}O0~Jz  
{ 29] G^f>  
'4Bm;&6M  
EUX\^c]n  
try{ O;jrCB  
URL url = new URL(sURL); (vJNHY M  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); yjJ5>cg  
httpConnection.setRequestProperty("User-Agent","NetFox"); @:vwb\azVD  
String sProperty = "bytes="+nStartPos+"-"; `kXs;T6&  
httpConnection.setRequestProperty("RANGE",sProperty); ]Q3ADh  
Utility.log(sProperty); %pL''R9VF  
0znR0%~  
_8UU'1d  
InputStream input = httpConnection.getInputStream(); 'S&zCTX7j  
//logResponseHead(httpConnection); 0pd'93C  
16(QR-  
p6Gy ,C.  
byte[] b = new byte[1024]; []1C$.5DD  
int nRead; *P=VFP  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) HBXOjr<,{  
{ 3;{kJQ  
nStartPos += fileAccessI.write(b,0,nRead); mNTzUoZF'@  
//if(nThreadID == 1) ;'@9[N9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 0=1T.4+=  
} U$A]8NZ$S  
^k">A:E2  
#h ]g?*}OJ  
Utility.log("Thread " + nThreadID + " is over!"); ?1 4{J]H4  
bDownOver = true; K Z91-  
//nPos = fileAccessI.write (b,0,nRead); n 0L^e  
} S|N_o   
catch(Exception e){e.printStackTrace ();} =X:Y,?  
} E*K;H8}s  
} )F]]m#`  
zHRplm+ i  
+\ .Lp 5  
//打印回应的头信息 jm/`iXnMf  
public void logResponseHead(HttpURLConnection con) `1fY)d^ZS  
{ >0TxUc_va  
for(int i=1;;i++) 0 /U{p,r6`  
{ Kis"L(C  
String header=con.getHeaderFieldKey(i); h3 }OX{k  
if(header!=null) I1M%J@Cz  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); lX4 x*  
Utility.log(header+" : "+con.getHeaderField(header)); +iRh  
else ENs&RZ;  
break; t-bB>q#3>  
} UySZbmP48  
} VuZuS6~#J  
g1"kTh  
Dp-z[]})1  
public void splitterStop() ]Q)OL  
{ #.)0xfGW)n  
bStop = true; RMu~l@  
} <R=Zs[9M1  
lzVq1@B  
/t$d\b17pX  
} {B*s{{[/'  
R$[vm6T?  
>!1-lfa8  
/* vV-`jsq20H  
**FileAccess.java n9ej7oj  
*//文件访问(定位,写) Z,Dl` w  
package NetFox; M!D3}JRm  
import java.io.*; wjB:5~n50k  
VTY 5]|;  
RQ" ,3.R==  
public class FileAccessI implements Serializable{ ?J~_R1Z  
^o&. fQ*  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Z o(rTCZX  
RandomAccessFile oSavedFile; z5*'{t)  
long nPos; u <v7;dF|s  
BuXqd[;K%  
M@v.c; Lt  
public FileAccessI() throws IOException Ne1$ee. NE  
{ Si;H0uPO  
this("",0); MeZf*' J  
} i5@ z< \  
*#+An<iT ;  
z[qDkL  
public FileAccessI(String sName,long nPos) throws IOException 3 {sVVq5Y  
{ T'Dv.h  
oSavedFile = new RandomAccessFile(sName,"rw"); [2 M'PT3  
this.nPos = nPos; T%*D~=fQ'  
oSavedFile.seek(nPos); ]2qo+yB  
} uiR8,H9*M  
DT&@^$?  
U-tTW*[1]  
public synchronized int write(byte[] b,int nStart,int nLen) }a(dyr`S  
{ 0*{%=M  
int n = -1; )|# sfHv7  
try{ ,/|T-Ka  
oSavedFile.write(b,nStart,nLen); m#\ dSl}  
n = nLen; bq0zxg%  
} )irEM  
catch(IOException e) 'YSHi\z ](  
{ z9Rp`z&`E  
e.printStackTrace (); 3eQ&F~S  
} YNsJZnGr8#  
p>8D;#Hm L  
0{-q#/  
return n; NyNXP_8  
} ' %o#q6O  
:& ."ttf=  
"87:?v[[1  
} =fFP5e ['  
sdw(R#GE  
=]0&i]z[.  
/* Se =`N  
**SiteInfoBean.java BR;D@R``}  
*/ t'k$&l}+  
package NetFox; 3AN/ H  
I^$fMdT  
smo~7;  
public class SiteInfoBean { bY~pc\V:`w  
'E""amIJ  
oe-\ozJ0  
private String sSiteURL; //Site's URL L) T (<  
private String sFilePath; //Saved File's Path Qh\60f>0  
private String sFileName; //Saved File's Name  H6/$d  
private int nSplitter; //Count of Splited Downloading File [S!/E4>['  
d>qY{Fdz  
'm kLCS  
public SiteInfoBean() Qd3 j%(  
{//nSplitter的缺省值为5 \LexR.Di  
//default value of nSplitter is 5 c'yxWZEv  
this("","","",5); C1 *v,i  
} nZYBE030  
/f;~X"!  
t;\Y{`  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) XU(eEnmo m  
{ 4@ai6,<  
sSiteURL= sURL; Qq|57X)P*  
sFilePath = sPath; FVJ GL  
sFileName = sName; k~w*W X'  
this.nSplitter = nSpiltter; X45%e!  
`3&v6  
r mg}N  
} 7J<5f)  
QhJiB%M  
8 v%o,"  
public String getSSiteURL() &^Q/,H~S  
{ c\AfaK^KF  
return sSiteURL; ;u)I\3`*!  
} $*fMR,~t&  
SO0PF|{\r  
;uP:"k  
public void setSSiteURL(String value) 20Wg=p9L  
{ sd|).;s}  
sSiteURL = value; 1p=]hC  
} +QJ#2~pE  
eehb1L2(b  
5$C-9  
public String getSFilePath() 11;MN  
{ #AQV(;r7@  
return sFilePath; A~70  
} $qj2w"'  
I b5rqU\  
E~"y$Fqe  
public void setSFilePath(String value) o?\?@H  
{ / %io+94  
sFilePath = value; C;^X[x%h7$  
} ~Z' ?LV<t  
c{w2Gt!  
qlPT Ll  
public String getSFileName() 0LJv'  
{ FU4L6n  
return sFileName; f ) L  
} )l DD\J7  
{"KMs[M  
`<d }V2rdz  
public void setSFileName(String value) R (n2A$  
{ &Au@S$ij  
sFileName = value; }k.Z~1y  
} ncT&Gr   
h <<v^+m  
IW] rb/H  
public int getNSplitter() aK^q_ghh[  
{ "3Y0`&:D  
return nSplitter; ey$&;1x#5  
} 6.yu-xm  
x7 ,5  
p9-K_dw3X@  
public void setNSplitter(int nCount) AFwdJte9e  
{ uQKT  
nSplitter = nCount; YPI-<vM~  
} O0H.C0}  
}  z+X}HL  
b@hqz!)l`  
'!B&:X)  
/* 5\VWCI  
**Utility.java 7s^'d,P  
*/ X 0+vXz{~g  
package NetFox; {]4LULq  
]3Sp W{=^(  
q'Pf]  
public class Utility { 7;@]t^d=$  
/Lr.e%  
+9sQZB# (  
public Utility() [j+sC*  
{ U8$27jq  
sc#qwQ#  
1 [Bk%G@D&  
} 1T n}  
?(_08O  
//线程睡眠 QQc -Ya!v  
public static void sleep(int nSecond) 1EX;MW-p<T  
{ E}Uc7G  
try{ *MW\^PR?  
Thread.sleep(nSecond); >uEzw4w  
} IO<6  
catch(Exception e) ="l/klYV  
{ b^vQpiz  
e.printStackTrace (); ) Hr`M B  
} YKK*ER0  
} &s!@29DXR  
2=!RQv~%  
//日志 Y"$xX8o  
public static void log(String sMsg)  uHRsFlw  
{ !&@615Vtw  
System.err.println(sMsg); 4 s9LB  
} t\O16O7S  
!^G\9"4A  
}4X0epPp;:  
public static void log(int sMsg) ]7c=PC  
{ rEz^  
System.err.println(sMsg); :NTO03F7v  
} `N8O"UcoBo  
} #}5uno  
&_8 947  
}"%N4(Kd  
/* M&M 6;Ph  
**TestMethod.java ~v6D#@%A  
*/ |CbikE}kL  
package NetFox; @BMx!r5kn  
goWuw}?  
\cM2k-  
public class TestMethod { #fM`}Ij.A  
P16~Qj  
VuZr:-K/  
public TestMethod() %E;'ln4h&,  
{ ///xx/weblogic60b2_win.exe Z0r'S]fe  
try{ yEy6]f+>+  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); \o3gKoL%  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); j.= 1rwPt  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <9b &<K:  
fileFetch.start(); es0hm2HT3  
} +jgSV.N  
catch(Exception e){e.printStackTrace ();} hOK8(U0  
n~Lt\K:  
)D%~` ,#pQ  
} WUTowr  
z`b,h\  
7F.4Ga;  
public static void main(String[] args) % A0/1{(  
{ ql~J8G9  
new TestMethod(); j_j]"ew)  
} j B{8u&kz)  
} >=w)x,0yX  
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