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http断点续传简单实现(java)

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/* =vc8u&L2  
**SiteFileFetch.java j!;y!g  
*/ qTD^Vz V  
package NetFox; Kfl#78$d  
import java.io.*; Z<^TO1xs9B  
import java.net.*; 6 7{>x[  
eg$y,Tx  
q|_t=YM@  
public class SiteFileFetch extends Thread { +M/1,&  
g&oAa;~o  
{'e%Hx  
SiteInfoBean siteInfoBean = null; //文件信息Bean T_=iJ: Q  
long[] nStartPos; //开始位置 gvl3NQQ%t  
long[] nEndPos; //结束位置 <4m@WG  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 z6+D=<  
long nFileLength; //文件长度 gV\{Qoj  
boolean bFirst = true; //是否第一次取文件 L/sMAB  
boolean bStop = false; //停止标志 QqU>V0y"w(  
File tmpFile; //文件下载的临时信息 xJSK"  
DataOutputStream output; //输出到文件的输出流 4UV<Q*B\F  
)%T< Mw2u  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) M7JQw/,xs  
public SiteFileFetch(SiteInfoBean bean) throws IOException QaYUcma~n  
{ Sh+$w=vC  
siteInfoBean = bean; 7\xGMCctM  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); cEc_S42Z  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); LqA&@  
if(tmpFile.exists ()) 7Fd`M To  
{ p,'Z{7HG  
bFirst = false; r3_O?b  
read_nPos(); yoc;`hO-  
} Z2cumx(  
else iF#|Z$g-(  
{ 2V6kCy@V  
nStartPos = new long[bean.getNSplitter()]; q*E<~!jL  
nEndPos = new long[bean.getNSplitter()]; xq<3*Bcw  
} d$}z,~sN  
*eLKD_D`!C  
X@ j.$0 eK  
<g4[p^A  
} _>k&M7OU4  
j[e<CGZ  
A)j',jE&1  
public void run() xS>d$)rIj  
{ >ukn<  
//获得文件长度 uz%<K(:Ov  
//分割文件 &ap&dM0@%a  
//实例FileSplitterFetch |2t1m 6\j  
//启动FileSplitterFetch线程 D{)K00mm  
//等待子线程返回 =]swhF+l-  
try{ , A@uSfC(  
if(bFirst) a#L:L8T;j  
{ c1x{$  
nFileLength = getFileSize(); a(Fx1`}  
if(nFileLength == -1) v%2@M  
{ rUL_=>3  
System.err.println("File Length is not known!"); AIU=56+I\  
} RcG 1J7#i  
else if(nFileLength == -2) xxS>O%  
{ Pn|;VCh  
System.err.println("File is not access!"); EpsjaOmAF  
} ,^K}_z\9f  
else "AcC\iq  
{ suF<VJ)&s  
for(int i=0;i<nStartPos.length;i++) ](2\w9i%  
{ ^_rBEyz@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Nm.G,6<J  
} yPXa  
for(int i=0;i<nEndPos.length-1;i++) K}j["p<!  
{ aB*'DDlx"r  
nEndPos = nStartPos[i+1]; wdo(K.m  
} w28&qNha  
nEndPos[nEndPos.length-1] = nFileLength; mY 1Gm|  
} ]o<&Q52|  
} M8{J  
{IgL H`@  
yRyUOTK  
//启动子线程 d"0=.sA  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ^1mnw@04  
for(int i=0;i<nStartPos.length;i++) CAT{)*xc  
{ 5"WI^"6b:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), N7 ox#=g  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), hC D6  
nStartPos,nEndPos,i); ,%X"Caz  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); LuE0Hb"S8  
fileSplitterFetch.start(); h%UM<TZ]"  
} qe<xH#6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), >.o<}!FW  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); W Yo>Md 8  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", %5yP^BL0  
nEndPos = " + nFileLength); ;Zt N9l  
// fileSplitterFetch[nPos.length-1].start(); fG_<HJS(~  
?l>Ra0  
#9e2+5s  
//等待子线程结束 T jrz_o)  
//int count = 0; r"&uW !~0  
//是否结束while循环 b'1m 9T780  
boolean breakWhile = false; %+ : $uk[  
8c3/n   
N# <X"&-_#  
while(!bStop) )zv"<>Q 6  
{ O/b1^ Y   
write_nPos(); ?[#4WH-G  
Utility.sleep(500); Memb`3  
breakWhile = true; \f-@L;8#  
"~:P-]`G  
uGU-MC *  
for(int i=0;i<nStartPos.length;i++) >v'@p  
{ Z/e^G f#i  
if(!fileSplitterFetch.bDownOver) %$6?em_  
{ u/.# zn@9h  
breakWhile = false; EL^j}P  
break; Ov~vK\  
} 9 K~X+N\  
} &ev#C%Nu  
if(breakWhile) CsX@u#  
break; ^OrO&w|  
l[Ko>  
u$rSM0CJ  
//count++; %{B4M#~  
//if(count>4) >uP1k.z'I  
// siteStop(); 7TB&Q*Zf  
} cMoBYk  
W_bA.z T{  
= J0r,dR  
System.err.println("文件下载结束!"); 2= )V"lR\  
} ?Ll1B3f  
catch(Exception e){e.printStackTrace ();} 95.s,'0  
} eHc.#OA&  
t;b1<TLn0  
5;CqGzgoP  
//获得文件长度 >>T,M@s-:  
public long getFileSize() #Fckev4  
{ B,4 3b O  
int nFileLength = -1; jP31K{G?  
try{ MZ:Ty,pw:O  
URL url = new URL(siteInfoBean.getSSiteURL()); lGXr-K?+Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lFV\Go  
httpConnection.setRequestProperty("User-Agent","NetFox"); Sd *7jW?  
1B`JvNtd  
^%t{:\  
int responseCode=httpConnection.getResponseCode(); p?' F$Wz  
if(responseCode>=400) ^0(`:*  
{ q rF:=?`E  
processErrorCode(responseCode); ; ]VLA9dC  
return -2; //-2 represent access is error bC,SE*F\  
} "Z#MR`;&29  
}_fVv{D   
4Ix~Feuph  
String sHeader; )(h<vo)-zX  
c8oE,-~  
+:3p*x%1H  
for(int i=1;;i++) 6Tg'9|g  
{ 5 J 7XVe>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); !|-:"hE1h  
//Utility.log(in.readLine()); g+QNIM>  
sHeader=httpConnection.getHeaderFieldKey(i); J:dNV <A^  
if(sHeader!=null) "u3 N9  
{ M5`wfF,j  
if(sHeader.equals("Content-Length")) v%)=!T ,  
{ 2#Y5*r's\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); *n`8 -=  
break; J@RV^2  
} ?MD\\gN  
} tg;AF<VI  
else "9OOyeKu%  
break; v03 ^  
} ;5:3 =F>ao  
} BFPy~5W  
catch(IOException e){e.printStackTrace ();} Wl{wY,u  
catch(Exception e){e.printStackTrace ();} kj@m5`G  
QuBaG<  
zvKypx  
Utility.log(nFileLength); z<u@::  
mU;\,96#  
 V/t-  
return nFileLength; *?!A  
} _))--+cL  
Z`yW2ON$'  
*W<|5<<u@  
//保存下载信息(文件指针位置) Za'}26  
private void write_nPos() eXQzCm  
{ [p96H)8YU  
try{ bX`VIFc  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ca"20NQ)  
output.writeInt(nStartPos.length); Y4)=D@JI  
for(int i=0;i<nStartPos.length;i++) 2^fSC`!  
{ jEW@~e  
// output.writeLong(nPos); qViolmDz  
output.writeLong(fileSplitterFetch.nStartPos); to3D#9Ep  
output.writeLong(fileSplitterFetch.nEndPos); KTjf2/  
} _;u@xl=  
output.close(); vL Qh r&I  
} O^4K o}  
catch(IOException e){e.printStackTrace ();} )5l9!1j  
catch(Exception e){e.printStackTrace ();} QO3QR/Ww  
} g({dD;  
*!u a?  
K2ry@haN  
//读取保存的下载信息(文件指针位置) 8p.O rdp  
private void read_nPos() "uD^1'IW2  
{ Zl7m:b2M  
try{ ym6gj#2m  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); QE~#eo  
int nCount = input.readInt(); wIK&EGQ  
nStartPos = new long[nCount]; T^.W'  
nEndPos = new long[nCount]; `YPNVm<3)  
for(int i=0;i<nStartPos.length;i++) vY(xH>Fd  
{ qh 9Ix  
nStartPos = input.readLong(); Z{ b($po  
nEndPos = input.readLong(); ?iaD;:'qE  
} S1W(]%0/  
input.close(); Hh0a\%!  
} ['_G1_p  
catch(IOException e){e.printStackTrace ();} APY*SeI V  
catch(Exception e){e.printStackTrace ();} ~ H $q  
} Uv(Uj3D  
,XmyC7y<  
S`&YY89{&  
private void processErrorCode(int nErrorCode) 4&^BcWqA*f  
{ l;'c6o0e  
System.err.println("Error Code : " + nErrorCode); :EZ"D#>y~  
} +)-`$N  
i>L>3]SRr{  
Avi8&@ya  
//停止文件下载 Wf:I 0  
public void siteStop() e X q}0-*f  
{ kV3Zt@+  
bStop = true; /WE1afe_R  
for(int i=0;i<nStartPos.length;i++) l} UOg   
fileSplitterFetch.splitterStop(); 3bPF+(`J  
$_NP4V8|z/  
.+Fh,bNYK  
} [";<YR7iRN  
} J;cTEB  
//负责部分文件的抓取 V-%Am  
**FileSplitterFetch.java "+:~#&r  
*/ 5b-: e? |  
package NetFox; >$p|W~x  
cQldBc  
y}!}*Qj+/  
import java.io.*; BjIKs~CT  
import java.net.*; KsBi<wY  
Z4@GcdZ  
*WpDavovyB  
public class FileSplitterFetch extends Thread { i& ybvTl  
=)9@rV&~  
1b-_![&]1  
String sURL; //File URL a5# B&|#q  
long nStartPos; //File Snippet Start Position U> s$}Y:+Z  
long nEndPos; //File Snippet End Position [p# }=&d  
int nThreadID; //Thread's ID 7iBN!"G0  
boolean bDownOver = false; //Downing is over p@+r&Mg%W"  
boolean bStop = false; //Stop identical a'2^kds  
FileAccessI fileAccessI = null; //File Access interface #Jqa_$\.  
o `N /w  
?O<D&CvB  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cN\Fgbt  
{ {expx<+4F  
this.sURL = sURL; 1C' _I  
this.nStartPos = nStart; Z/hgr|&}  
this.nEndPos = nEnd; \,5OPSB  
nThreadID = id; 1O,<JrE+-  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 V,qc[*_3  
} mh=YrDU+L  
2RC|u?+@  
P\R#!+FgW8  
public void run() KWH l+p L  
{ q2C._{ 0'  
while(nStartPos < nEndPos && !bStop) wio}<Y6Xz  
{ _]# ^2S  
;VAHgIpx;  
zwa%$U  
try{ uWE :3  
URL url = new URL(sURL);  }L.&@P<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();  *c6o#[l  
httpConnection.setRequestProperty("User-Agent","NetFox"); eAD uk!Iq  
String sProperty = "bytes="+nStartPos+"-"; #N'W+M /  
httpConnection.setRequestProperty("RANGE",sProperty); 1fzHmD  
Utility.log(sProperty); l4+Bs!i`  
t}]R0O.s  
qoXncdDHZ  
InputStream input = httpConnection.getInputStream(); ^yo~C3 r~  
//logResponseHead(httpConnection); >MeM  
n6Qsug$z  
^$I8ga  
byte[] b = new byte[1024]; ckTk2xPQ  
int nRead; 1SGLA"r  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) x<es1A'u6  
{ MQ{.%  
nStartPos += fileAccessI.write(b,0,nRead); o6[aP[~F  
//if(nThreadID == 1) |kXx9vGq@  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); at-+%e  
} z[`O YwsW  
-]K9sy)I  
R#x~f  
Utility.log("Thread " + nThreadID + " is over!"); Btgxzf  
bDownOver = true; ~l@ h  
//nPos = fileAccessI.write (b,0,nRead); NP#:} )  
} kED1s's  
catch(Exception e){e.printStackTrace ();} ^Voi 4;  
} B<" `<oG@|  
} BrO" _  
Dxlpo! ?#  
:|tWKA  
//打印回应的头信息 yHk}'YP  
public void logResponseHead(HttpURLConnection con) \6)]!$F6:  
{ tr t^o  
for(int i=1;;i++) e 1$<,.>  
{ aF41?.s  
String header=con.getHeaderFieldKey(i); ,p\:Z3{ZH  
if(header!=null) e(~9JP9  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ^L@2%}6b`  
Utility.log(header+" : "+con.getHeaderField(header)); e: aa  
else d~F4  
break; .*(xkJI3  
} 4Lb!Au|Y  
} ~0 Ifg_G  
hE|W%~Jx  
&Q`{ Gk  
public void splitterStop() G)G 257K"~  
{ j @HOU~x  
bStop = true; tvlrUp  
} [ u.r]\[J  
x [_SNX"  
O ;dtz\  
} 'fIoN%  
'C2X9/!,  
s9)U",  
/* #@3& 1 }J/  
**FileAccess.java n,_q6/!  
*//文件访问(定位,写) <Cbi5DtR  
package NetFox; NrK.DY4  
import java.io.*; Y*Ra!]62  
<(c_[o/  
5mYX#//:  
public class FileAccessI implements Serializable{ iX|K4.Pz{  
lPaTkZw  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ;[-TsX:  
RandomAccessFile oSavedFile; NtfzAz/  
long nPos; aVvma=  
Id}/(Pkq  
{gkzo3  
public FileAccessI() throws IOException EQTJ=\WFF  
{ g]Jt (aYK  
this("",0); w5+H9R6  
} + ;LO|!  
Rl/5eE8  
5w+KIHhN|  
public FileAccessI(String sName,long nPos) throws IOException r&y0`M  
{ 31^Jg  
oSavedFile = new RandomAccessFile(sName,"rw"); tSVWO] <  
this.nPos = nPos; =f/CBYNw@V  
oSavedFile.seek(nPos); iLC.?v2=  
} dtT: ,&  
@y!oKF  
Mm)yabP  
public synchronized int write(byte[] b,int nStart,int nLen) !y\r.fm!A  
{ L}a-c(G+8  
int n = -1; &pzf*|}  
try{ }NJKkj?  
oSavedFile.write(b,nStart,nLen); 'w z6Zt  
n = nLen; 1 ]A$  
} !*1 $j7`tP  
catch(IOException e) o"!C8s_6  
{ XU y[l  
e.printStackTrace (); e~U]yg5X-  
} ZQk!Ia7  
@=sM')f&  
2<FEn$n[  
return n; 2z9s$tp  
} { MV,>T_  
?Qxf~,F  
FMi:2.E  
} HSk_'g(\0  
2Onp{,'}  
:o 8XG  
/* S54q?sb_  
**SiteInfoBean.java TtQ'I}7q  
*/ 2O 2HmL  
package NetFox; 21$E.x 6  
nSv@FT'~z  
D"V(A\sZ  
public class SiteInfoBean { 7tbY>U8  
Yu$QL@  
`y|_hb  
private String sSiteURL; //Site's URL Uv m:`e~?  
private String sFilePath; //Saved File's Path ZXIw^!8@/  
private String sFileName; //Saved File's Name oo\7\b#Jx  
private int nSplitter; //Count of Splited Downloading File $<QrV,T  
d%za6=M  
bFIM07  
public SiteInfoBean() 9 {wRqY  
{//nSplitter的缺省值为5 [=BccT:b  
//default value of nSplitter is 5 o(k{Ed  
this("","","",5); VIHuo,  
} F[v:&fle  
BW:HKH.k  
>qz#&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Q+oV? S3{  
{ JC MUK<CG  
sSiteURL= sURL; V3>tW,z  
sFilePath = sPath; h UC157  
sFileName = sName; BsU}HuQZQ  
this.nSplitter = nSpiltter; ,v<7O_A/e  
]rG/?1'^i  
/9e?uC6  
} n$F~  
Fw S>V2R  
uGv|!UQw  
public String getSSiteURL() {Q}F.0Q  
{ L>h|1ZK  
return sSiteURL; N;`/>R4|I  
} B[I9<4}  
?<`oKBn  
z2>LjM) #  
public void setSSiteURL(String value) [l3ys  
{ $nb.[si\  
sSiteURL = value; 6w=`0r3hy  
} -&COI-P8  
XEnu0 gr  
W=#AfPi$&  
public String getSFilePath() }T0O~c{$i  
{ PY;tu#W!%  
return sFilePath; Khb Ku0Z  
} AhD C5ue=  
dU#-;/}o  
CLTkyS)C  
public void setSFilePath(String value) ;=7K*npT  
{ V)5K/ U{  
sFilePath = value; *a\6X( ~  
} 9O -2  
m):*>o55  
!> =ybRe  
public String getSFileName() 64mg:ed&  
{ 8IA1@0n&  
return sFileName; lLp,sNAj  
} :r@t'  
`% QvCAR  
D<m0G]Ht*  
public void setSFileName(String value) c"v75lW-J  
{ *i}X(sfe  
sFileName = value; .L+XV y  
} wk ^7/B  
{fnx=BaG  
c:.~%AJx  
public int getNSplitter() ^nK<t?KS  
{ x9,jXd  
return nSplitter; .[ }G{%M~[  
} F#>00b{Q  
{vGJ}q?Sd"  
+U1 Ir5Lx  
public void setNSplitter(int nCount) a%e`  
{ e{7\pQK  
nSplitter = nCount; Bb:C^CHIQm  
} qa-FLUkIk!  
} r=&,2meo  
4 s ax  
'w27Lt'V  
/* ni&|;"Nt-  
**Utility.java #]x3(}3W  
*/ VJ=>2'I  
package NetFox;  kDE-GX"Y  
~\mh\a&  
i1|>JM[V  
public class Utility { +4.s4&f)  
 #D4  
{BmqUoZrC  
public Utility() G.H8 ><%  
{ T#H^ }`  
!uQT4< g  
^3TNj  
} N(Ru/9!y"  
Lx wi"ndP  
//线程睡眠 |82q|@e  
public static void sleep(int nSecond) 1!KROes4  
{ ~PI2G 9  
try{ E?G'F3i  
Thread.sleep(nSecond); J7* o%W*V  
} X58U>4a  
catch(Exception e) 4%^z=%  
{ {_Wrs.a'8  
e.printStackTrace (); *^uK=CH1?(  
} n&njSj/  
} W48RZghmx  
RkE)2q[5  
//日志 Ln4]uqMG.  
public static void log(String sMsg) _Xt/U>N  
{ 16zReI(  
System.err.println(sMsg); V9,<>  
} 8i154#l+\  
dMH_:jb  
GLn=*Dh#  
public static void log(int sMsg) r*+~(83k  
{ .`}TND~  
System.err.println(sMsg); 9h amxi  
} q1T)H2S  
} ->rqr#  
{5~h   
F(yR\)!C  
/* 68XJ`/d  
**TestMethod.java c|k_[8L  
*/ Cgx:6TRS  
package NetFox; k1<^Ept  
`Pvi+:6\Y  
8f9wUPr  
public class TestMethod { Hw o _;fV  
LUbj^iQ9  
DjM*U52Yfj  
public TestMethod() sfyLG3$/  
{ ///xx/weblogic60b2_win.exe LN|(Z*  
try{ He(65ciT<O  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); {  c#US  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); Y(g_h:lf,]  
SiteFileFetch fileFetch = new SiteFileFetch(bean); Z 2N6r6  
fileFetch.start(); Vr EGR$  
} w$:\!FImx  
catch(Exception e){e.printStackTrace ();} gx.\H3y  
In1W/ ?  
;OlnIxH(W  
} 1'qXT{f/~  
k( :Bl  
6G2~'zqPc~  
public static void main(String[] args) < D/K[mz-  
{ >qo!#vJc a  
new TestMethod(); ?6CLUu|7n  
} R iLl\S#  
} '#7k9\  
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