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http断点续传简单实现(java)

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/* Sy.%>$z  
**SiteFileFetch.java "c~``i\G   
*/ aU +uPP  
package NetFox; n"iaE  
import java.io.*; dh}"uM}a  
import java.net.*; vIi&D;  
.nr%c*JUp  
 b%F'Ou~  
public class SiteFileFetch extends Thread { cJT_Qfxx  
s!09cS  
P[`>*C\9c  
SiteInfoBean siteInfoBean = null; //文件信息Bean QncjSaEE  
long[] nStartPos; //开始位置 mFpj@=^_G  
long[] nEndPos; //结束位置 ! , ]Fx  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 /;TD n>lq  
long nFileLength; //文件长度 $m.'d*e5  
boolean bFirst = true; //是否第一次取文件 j}h%, 7  
boolean bStop = false; //停止标志 9 [E/^  
File tmpFile; //文件下载的临时信息 2DZ&g\|  
DataOutputStream output; //输出到文件的输出流 |[V6R\l39  
pdQaVe7tRo  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) ;(g"=9e  
public SiteFileFetch(SiteInfoBean bean) throws IOException GYT0zMMf  
{ Nde1`W]:  
siteInfoBean = bean; kyB>]2  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); MmfshnTN  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %AgCE"!  
if(tmpFile.exists ()) BaCzN;)  
{ y(Pv1=e  
bFirst = false; Pw Amnk !  
read_nPos(); odeO(zuU  
} u7wZPIC{_  
else 48GaZ@v  
{ CZv^,O(M?2  
nStartPos = new long[bean.getNSplitter()]; p{V(! v|  
nEndPos = new long[bean.getNSplitter()]; [di&N!Ao  
} :OaGdL   
tN)Vpb\J  
z_&T>ME  
Fw#wVs)@:  
} H~<wAer,Op  
K!88 Nox(  
toox`|  
public void run() su=]gE@  
{ U%2{PbL  
//获得文件长度 /P{'nI  
//分割文件 6:TA8w|  
//实例FileSplitterFetch L-3wez;hm  
//启动FileSplitterFetch线程 vinn|_s%  
//等待子线程返回 $)O\i^T  
try{ # f{L;  
if(bFirst) f2$<4H hmm  
{ j62oA$z  
nFileLength = getFileSize(); 0[OlJMVf  
if(nFileLength == -1) TP/bPZY  
{ 2f0_Xw_V_  
System.err.println("File Length is not known!"); #fe zUU  
} H`U>ZJ.  
else if(nFileLength == -2) ^W,x  
{ Fc"+L+h@W  
System.err.println("File is not access!"); y{qKb:~wv  
} Z@>WUw@ F  
else O%s?64^U  
{  -Ly A  
for(int i=0;i<nStartPos.length;i++) MW.,}f  
{ [%7oq;^J  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `>$l2,  
} {[FJkP2l  
for(int i=0;i<nEndPos.length-1;i++) !% yd'"6Dl  
{ q/\Hh9`  
nEndPos = nStartPos[i+1]; Zv1/J}+  
} |Q~5TL>b  
nEndPos[nEndPos.length-1] = nFileLength; }2_ i<4,L  
} UXV>#U?  
} =Cr F(wVO"  
+QFY. >KH  
vn=0=(  
//启动子线程 GI*2*m!u  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; |/p2DU2  
for(int i=0;i<nStartPos.length;i++) 0f|nI8,z  
{ \wo'XF3:  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +QVe -  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), V4 Wn  
nStartPos,nEndPos,i); 0--0+?  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); mMV -IL  
fileSplitterFetch.start(); <</ Le%  
} f<~S0[H  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), H;eOrX {GT  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); @8 GW?R  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ns1@=f cO  
nEndPos = " + nFileLength); L%O( I  
// fileSplitterFetch[nPos.length-1].start(); :>otlI<0t  
'gwh:8Xc  
-nrfu)G  
//等待子线程结束  ~/kx  
//int count = 0; ? v2JuhRe  
//是否结束while循环 _-g?6q  
boolean breakWhile = false; /SZg34%  
b:}+l;e5 2  
]):kMRv  
while(!bStop) CK+_T}+-  
{ O(QJiS  
write_nPos(); oVSq#I4  
Utility.sleep(500); YV0K&d  
breakWhile = true; Fps.Fhm  
~'l.g^p bv  
*6e 5T  
for(int i=0;i<nStartPos.length;i++) w_!]_6%{b  
{ cU'^ Ja?%  
if(!fileSplitterFetch.bDownOver) (GdL(H#IL  
{ %,M(-G5j;  
breakWhile = false; M%8:  
break; #I.Wmfz  
}  /P/S0  
} R\wG3Oxol  
if(breakWhile) p$cSES>r:  
break; UE9r1g`z  
M _z-~G  
:2fz4n0{/  
//count++; ` cgS yRD]  
//if(count>4) hD:$Sv/H  
// siteStop(); oLXQ#{([  
} jreY'y:  
{ +%S{=j  
A"@C }f  
System.err.println("文件下载结束!"); ~\z\f} w  
} \;>idbV  
catch(Exception e){e.printStackTrace ();} jpCQ2XD:  
} M/,jHG8v  
'J`%[,@V  
v&EHp{8Qd  
//获得文件长度  ? h$>7|  
public long getFileSize() 3wBc`vJ!  
{ Uv06f+P(  
int nFileLength = -1; +FoR;v)z=F  
try{ J !:ss  
URL url = new URL(siteInfoBean.getSSiteURL()); e ga< {t  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); S/ Y1NH  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7='M&Za  
:B<lDcFKJ  
zA![c l>$  
int responseCode=httpConnection.getResponseCode(); `q 4%  
if(responseCode>=400) 5UwaBPj4  
{ !=.5$/  
processErrorCode(responseCode);  @GYM4T  
return -2; //-2 represent access is error LV&tu7c  
} c4R6E~S  
Pv`^#BX'  
wK[xLf  
String sHeader; Ve&(izIh  
o(. PxcD  
C`D5``4  
for(int i=1;;i++) =^P<D&%q  
{ a<[@p  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Ywf.,V  
//Utility.log(in.readLine()); .! LOhZ  
sHeader=httpConnection.getHeaderFieldKey(i); FxC@KZG  
if(sHeader!=null) pbivddi2  
{ h{]l?6`  
if(sHeader.equals("Content-Length")) ?<Dinq  
{ C,w$)x5kls  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); `n7z+  
break; M[0@3"}}  
} aT#R#7<Eg  
} H;<hmbN?d  
else ' hL\xf{  
break; f4zd(J  
} & h9ji[  
} X+{4,?04+  
catch(IOException e){e.printStackTrace ();} Od'!v&  
catch(Exception e){e.printStackTrace ();} 0 )#5_-%  
/r|^Dc Nx  
]7ROCJ;  
Utility.log(nFileLength); :JSOj@s  
S >uzW #  
"j9,3yJT  
return nFileLength; OFCOMM  
} Warz"n]iC  
'?_;s9)  
i7}) VDsZ  
//保存下载信息(文件指针位置) rZZueYuXO  
private void write_nPos() a[)in ,3  
{ j3~:\H  
try{ Tc@r#!.m  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @Q3aJ98)2  
output.writeInt(nStartPos.length); X#(?V[F]  
for(int i=0;i<nStartPos.length;i++) k oC2bX  
{ KLs%{'[7:  
// output.writeLong(nPos); {y'c*NS  
output.writeLong(fileSplitterFetch.nStartPos); cp2e,%o  
output.writeLong(fileSplitterFetch.nEndPos); u|=_!$8  
} ZYrXav<  
output.close(); rU5gQq;  
} ow ~(k5k:  
catch(IOException e){e.printStackTrace ();} F`U%xn,  
catch(Exception e){e.printStackTrace ();} D2~e@J(K  
} kVQKP  U  
;]MHU/  
]E88zWDY`  
//读取保存的下载信息(文件指针位置) [z`U 9J  
private void read_nPos() o8RagSIo8  
{ <r,l  
try{ IR|AlIv  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ld4QhZia  
int nCount = input.readInt(); gec<5Ewg  
nStartPos = new long[nCount]; N9Yc\?_NU_  
nEndPos = new long[nCount]; A--Hg-N|  
for(int i=0;i<nStartPos.length;i++) h{yqNl  
{  s6 w</  
nStartPos = input.readLong(); $TL~SVHj;{  
nEndPos = input.readLong(); Nj qUUkc  
} 91r#lDR  
input.close(); L\5j"] }`  
} LqPn$rZ|$  
catch(IOException e){e.printStackTrace ();} !Z,h5u\.w  
catch(Exception e){e.printStackTrace ();} ' V;cA$ $  
} fC2e}WR   
kp[+Iun?  
l[l('-f  
private void processErrorCode(int nErrorCode) IBC P6[  
{ D(s[=$zua  
System.err.println("Error Code : " + nErrorCode); 8k]'P*9ulz  
} 'd^U!l  
r@H<@Vuc  
x;l\#x/<  
//停止文件下载 y|nMCkuX  
public void siteStop() 1[a;2x A~  
{ <jQ?l% \  
bStop = true; ;-lk#D?n9  
for(int i=0;i<nStartPos.length;i++) Z'>Xn^  
fileSplitterFetch.splitterStop(); j\("d4n%C  
+y>D3I  
0~H(GG$VH  
} AM1J ^Dp  
} ^vLHs=<  
//负责部分文件的抓取 N' t*eCi  
**FileSplitterFetch.java Mje6Q  
*/ O$E3ry+?  
package NetFox; 9l@VxX68M  
<K%qaf  
3lqR(Hh3  
import java.io.*; mZDrvTI'  
import java.net.*; 0iinr:=u  
4T`u?T]  
l&(,$RmYp  
public class FileSplitterFetch extends Thread { =4"D8 UaHr  
@|6n.'f+  
4iBp!k7  
String sURL; //File URL G\?fWqx  
long nStartPos; //File Snippet Start Position { ,/mQ3  
long nEndPos; //File Snippet End Position 7@$Hua,GY  
int nThreadID; //Thread's ID G)';ucs:,  
boolean bDownOver = false; //Downing is over QDRSQ[\  
boolean bStop = false; //Stop identical Gmi4ffIb3  
FileAccessI fileAccessI = null; //File Access interface FRQ0tIp  
3gaijVN  
b-'41d}Hn  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException WLQm|C,  
{ K3$83%E  
this.sURL = sURL; Pdmfn8I]%  
this.nStartPos = nStart; &/d;4Eu  
this.nEndPos = nEnd;  57Q^ "sl  
nThreadID = id; fD  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 x1W<r)A )r  
} -~~"}u  
~&4Hc%*IB  
YgNt>4K  
public void run() p [4/Nq,c  
{ >c*}Do{lG  
while(nStartPos < nEndPos && !bStop) Cb7f-Eag  
{ F=U3o=-:  
8 sZ~3  
X(U CN0#  
try{ Fd":\7p  
URL url = new URL(sURL); 8rAOs\ys  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cH?j@-pY  
httpConnection.setRequestProperty("User-Agent","NetFox"); XZLo*C!MG  
String sProperty = "bytes="+nStartPos+"-"; "jH=O(37  
httpConnection.setRequestProperty("RANGE",sProperty); $NC1>83  
Utility.log(sProperty);  iUJqAi1o  
eEePK~%c  
;|6kFBGC"+  
InputStream input = httpConnection.getInputStream(); 0tv"tA;  
//logResponseHead(httpConnection); 1P:r=Rt/  
i[/g&fx  
T3,"g=  
byte[] b = new byte[1024]; l)m\i_r:  
int nRead; k3h,c;  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) A9' [x7N  
{ 4n @}X-)  
nStartPos += fileAccessI.write(b,0,nRead); ;,![Lar5L  
//if(nThreadID == 1) o?$kcI4  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); jFY6}WY)}7  
} &Ed7|k]H  
kRo dC(f @  
m=<Tylv  
Utility.log("Thread " + nThreadID + " is over!"); &^3KF0\Q  
bDownOver = true; ="<5+G  
//nPos = fileAccessI.write (b,0,nRead); ! /;@kXN  
} mr dG- t(k  
catch(Exception e){e.printStackTrace ();} kwU~kcM  
} x%ju(B>  
} _-eF &D  
~G|un}g=  
qq" &Bc>  
//打印回应的头信息 S=H<5*]g  
public void logResponseHead(HttpURLConnection con) WPi^;c8  
{ 0g}+%5]yg  
for(int i=1;;i++) .V G$`g"  
{ -\6nT'P  
String header=con.getHeaderFieldKey(i); MG)wVS<d_  
if(header!=null) 9v>BP`Mg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Pw i6Ly`  
Utility.log(header+" : "+con.getHeaderField(header)); eSo/1D  
else }_93}e  
break; _Mq0QQ42  
} S`HshYlE q  
} mL/]an@Y  
$Y.Z>I;  
2 g5Ft  
public void splitterStop() M\O6~UFq!  
{ ^Yz.,!B[  
bStop = true; k~f3~-"  
} 0f~7n*XH  
8}9|hT;  
q}gj.@Q"  
} n!=%MgF'*p  
EN6a? }5  
!T;*F%G9  
/* 4|*b{Ni  
**FileAccess.java  +]Ca_`  
*//文件访问(定位,写) $ZX^JWq  
package NetFox; zy\p,  
import java.io.*; ^% y<7>%  
)D\cm7WX^[  
"{>I5<:t  
public class FileAccessI implements Serializable{ .BN~9w  
fDy Fkhc  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /*3[9,  
RandomAccessFile oSavedFile; .3WDtVE  
long nPos; qjcy{@ j  
cpz'upVOZ  
`L p3snS  
public FileAccessI() throws IOException ~Wy&xs ZH  
{ Trd/\tX#v&  
this("",0); 3 $7TeqfAC  
} 3=o^Vv  
P Z5BtDm  
ga0>J_  
public FileAccessI(String sName,long nPos) throws IOException |Y' xtOMX  
{ V_Z~$  
oSavedFile = new RandomAccessFile(sName,"rw"); 86Q\G.h7  
this.nPos = nPos; ?"MJ'u  
oSavedFile.seek(nPos); "0x"X w#I  
} ?DPN a  
xK4b(KJj  
g-^Cf   
public synchronized int write(byte[] b,int nStart,int nLen) vqh@)B+)  
{ I)$`@.  
int n = -1; K07SbL7g!p  
try{ OiPE,sv  
oSavedFile.write(b,nStart,nLen); &1O[N*$e  
n = nLen; 4k'2FkDA  
} gM=oH   
catch(IOException e) A:Y]<jt  
{ v4]7"7GuW  
e.printStackTrace (); LL,&!KW[S  
} & sbA:xZBA  
fsc^8  
l!Q |]-.@  
return n; #fg RF  
} hpJ[VKe  
O[+![[N2  
*O') {(  
} S.o 9AUv9  
Id8^6FLw  
Hb&-pR@e\?  
/* y- S]\tu  
**SiteInfoBean.java AHsp:0Ma#  
*/ PAF2=  
package NetFox; |a@$KF$  
#"|Y"#@k  
uS :3Yo  
public class SiteInfoBean { S-[]z*  
nA8]/r1k  
=\s(v-8  
private String sSiteURL; //Site's URL _2{i}L  
private String sFilePath; //Saved File's Path ;OW`(jC  
private String sFileName; //Saved File's Name :b+C<Bp64r  
private int nSplitter; //Count of Splited Downloading File @W3fKF9*R  
5A]IiX4Z  
G hH0-g{-  
public SiteInfoBean() ]9z{ 95  
{//nSplitter的缺省值为5 K~$o2a e  
//default value of nSplitter is 5 n y6-_mA]  
this("","","",5); (bH*i\W  
} v ?@Ys+V  
w?kdM1T  
2d+IROA  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ,lm.~%}P*  
{ ;zI;oY#.y  
sSiteURL= sURL; W2h^ShG  
sFilePath = sPath; qe!`LeT#  
sFileName = sName; _$/(l4\T[  
this.nSplitter = nSpiltter; C`OdMM>D  
l= 5kd.{  
4&/u1u 0  
} bG nBV7b  
$5nOiaQL  
*ie#9jA  
public String getSSiteURL() ) ^PY-~o[  
{ Gad! }dz  
return sSiteURL; 7 ]a6dMh  
} '/ 3..3k  
Bt|S!tEy  
u{=(] n  
public void setSSiteURL(String value) ew B&PR  
{ {>>ozB.  
sSiteURL = value; 5o\yhYS:  
} 04NI.Jv  
@TC_XU)&  
k{Yj!C> #  
public String getSFilePath() Bn*D<<{T  
{ 5{qFKo"g@,  
return sFilePath; J!%Yy\G  
} O?NAbxkp  
LoUi Yf  
\Oh9)X:I  
public void setSFilePath(String value) ;hNn F&l  
{ E,E:WuB  
sFilePath = value; rFZB6A<(]  
} Ac<V!v71  
":?>6'*1  
qJB9z0a<Ov  
public String getSFileName() 0iqa]Am  
{ YMLo~j4J  
return sFileName; 3toY#!1Ch  
} #B:J7&@fn  
i%>]$*  
K) $.0S9d  
public void setSFileName(String value) MGX %U6  
{ =K{$?%"  
sFileName = value; *ghkw9/  
} N!m-gymmF  
b")&"o)G2W  
Wcn3\v6_  
public int getNSplitter() ?I)-ez  
{ HY9H?T  
return nSplitter; ovzIJbf  
} 2#C!40j&\  
hf0G-r_ow  
U#1T HO`  
public void setNSplitter(int nCount) dz &| 3o  
{ K+Al8L?K_  
nSplitter = nCount; g1muT.W]S  
} eV^@kI4  
} 7J./SBhB  
cEi{+rfZd|  
o %A4wEye  
/* %l[Cm4  
**Utility.java xZPSoxu  
*/ `23&vGk}  
package NetFox; 1F-o3\  
Q[scmP^$^  
Tz+2g&+  
public class Utility { \bqNjlu  
IyIh0B~i  
Yi&;4vC  
public Utility() NWNH)O@  
{ v<_}Br2I[  
UP 1Y3  
D}vgXzD  
} n_AW0i .  
f( hK>H  
//线程睡眠 ^i&/k  
public static void sleep(int nSecond) SG |!wH^  
{ :aLShxKA  
try{ N+\#k*n?  
Thread.sleep(nSecond); Q#urx^aw  
} t= "EbPE  
catch(Exception e) =t<!W  
{ u!oHP  
e.printStackTrace (); 7'7bIaJk  
} ' IFbD["r  
} RPP xiYU^  
HcUivC  
//日志 TgJx%  
public static void log(String sMsg) $@Zb]gavt?  
{ jWiZ!dtUZ  
System.err.println(sMsg); 5*[zIKdt2  
} 7on$}=%  
F0o7XUt  
k^z)Vu|f.  
public static void log(int sMsg) V!3G\*$?  
{ 'SY jEhvw  
System.err.println(sMsg); IpGq_TU  
} \r^=W=  
} P9:7_Vc  
hUSr1jlA  
rl'YyO}2  
/* RZjTUMAz4  
**TestMethod.java ?JzLn,&  
*/ ($7>\"+Tl  
package NetFox; 5oGnPF  
|Q`}a %  
YN n,{Xi  
public class TestMethod { SEr\ u#  
{F6hx9?  
J [2;&-@  
public TestMethod() I"#jSazk  
{ ///xx/weblogic60b2_win.exe 6|X  
try{ $n(?oyf  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); g % q7  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); GuQ3$B3j  
SiteFileFetch fileFetch = new SiteFileFetch(bean); "^;'.~@e8  
fileFetch.start();  ?Vbe  
} f";70}_  
catch(Exception e){e.printStackTrace ();} "}*P9-%  
3lM mSKN  
7`6n]4e  
} L7G':oA_`p  
1{_tV^3@  
;Y?7|G97*S  
public static void main(String[] args)  h#^IT  
{ +I/7eIG?|  
new TestMethod(); *ls}r5k2Y  
} _Z#yI/5r  
} #lM!s  
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