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http断点续传简单实现(java)

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/* |H4'*NP"  
**SiteFileFetch.java 24Fxx9 g  
*/ b+hY^$//  
package NetFox; [ZbK)L+_  
import java.io.*; [ n2udV  
import java.net.*; 8f.La  
W#[!8d35$  
-{h[W bf  
public class SiteFileFetch extends Thread {  #L)rz u  
bq O"k t  
X`b5h}c  
SiteInfoBean siteInfoBean = null; //文件信息Bean 2YyZiOMSc  
long[] nStartPos; //开始位置 "->:6Oe2   
long[] nEndPos; //结束位置 63HkN4D4  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 7yp*I[1Qf>  
long nFileLength; //文件长度 ?>Aff`dHY  
boolean bFirst = true; //是否第一次取文件 m C Ge*V}  
boolean bStop = false; //停止标志 lu_Gr=#O  
File tmpFile; //文件下载的临时信息 z@i4dC  
DataOutputStream output; //输出到文件的输出流 Eg*3**gTO  
Ub,unU  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) L ~w=O!  
public SiteFileFetch(SiteInfoBean bean) throws IOException oK6lCGM5  
{ 7,TWCVap  
siteInfoBean = bean; ,k!a3"4+TJ  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7&4,',0VL  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); .a*$WGb  
if(tmpFile.exists ()) Be+:-t)  
{ TpgBS4q  
bFirst = false; pC-OZ0  
read_nPos(); [Jo TWouNU  
} w>u Z$/  
else 3;NRW+  
{ jhv1 D' >6  
nStartPos = new long[bean.getNSplitter()]; fXe-U='  
nEndPos = new long[bean.getNSplitter()]; ^A`(  
} !\1W*6U8;  
lIg2iun[n  
9#ft;c  
09Y?!,  
} c'";3 6y  
2(Uz9!<V  
G:`Jrh  
public void run() K"7;Y#1g  
{ 'qAfei']  
//获得文件长度 cg0 0t+  
//分割文件 sG2 3[t8  
//实例FileSplitterFetch ,<b|@1\k  
//启动FileSplitterFetch线程 A@(h!Cq  
//等待子线程返回 fhKiG%i'l  
try{ bK\WdG\;  
if(bFirst) Y&+_p$13  
{ l-}5@D[  
nFileLength = getFileSize(); AijTT%  
if(nFileLength == -1) t<F]%8S  
{ Z&jb,eh2  
System.err.println("File Length is not known!"); *)1Vs'!-  
} -WvgK"k  
else if(nFileLength == -2) R2THL  
{ <[:7#Yo g  
System.err.println("File is not access!"); D1~x  
} $'YKB8C  
else Tw;qY  
{ w/5^R  
for(int i=0;i<nStartPos.length;i++) D"4&9"CU  
{ #Jz&9I<OKx  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 86fK= G:>  
} +'KE T,  
for(int i=0;i<nEndPos.length-1;i++) W#I:j: p  
{ ,M.!z@  
nEndPos = nStartPos[i+1]; Y{vwOs  
} k_>Fw>Y  
nEndPos[nEndPos.length-1] = nFileLength; )kKmgtj  
} o Xi}@  
} A]Tcj^#  
9<h]OXv  
ds;cfj[  
//启动子线程 .#55u+d,  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [Am`5&J  
for(int i=0;i<nStartPos.length;i++) |( 9#vt#  
{ V!77YFen %  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RB7AI !'a?  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 8+ F}`lLA  
nStartPos,nEndPos,i); 76A>^Bs\/  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); G yAgPz  
fileSplitterFetch.start(); dM s||&|&  
} 2FIR]@MQd  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +O$:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); _gm?FxV:  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ,ah*!Zm.kk  
nEndPos = " + nFileLength); #3K,V8(  
// fileSplitterFetch[nPos.length-1].start(); [Z5[~gP3  
Zfy~mv$  
4s~HfxYT  
//等待子线程结束 H8$<HhuZM  
//int count = 0; AwXt @!(  
//是否结束while循环 ^+%tlX_+.  
boolean breakWhile = false; t'Eb#Nup3  
G_M:0YI@  
?QMclzh*-  
while(!bStop) !/6\m!e|1R  
{ b-BM"~N'  
write_nPos(); #PslrA. E  
Utility.sleep(500); _2m[(P9d  
breakWhile = true; yS)- &t!;  
f `y" a@  
_}zo /kDA  
for(int i=0;i<nStartPos.length;i++) Wm)-zvNY;  
{ jF2[bzY4  
if(!fileSplitterFetch.bDownOver) }F{C= l2  
{ f2 ydL/M,  
breakWhile = false; qE0FgqRB  
break; ?""\  
} CZJHE>  
} X'FEOF  
if(breakWhile) =t3vbV  
break; QB/7/PW{H\  
8 "_Bq  
{_zV5 V  
//count++; \E$1lc  
//if(count>4) N7*CP|?E  
// siteStop(); .Vo"AuC}  
} |66m` <  
3(!/["@7  
cBifZv*l  
System.err.println("文件下载结束!"); F0&~ ?2nG  
} Ap]4QqU  
catch(Exception e){e.printStackTrace ();} 0)d?Y  
} vWU%ST  
Opv1B2  
+_qh)HX  
//获得文件长度 f?%qUD_#  
public long getFileSize() `'p`PyMt`  
{ (2z%U  
int nFileLength = -1; m|]j'g?{}(  
try{ ,b<9?PM  
URL url = new URL(siteInfoBean.getSSiteURL()); 5<89Af&&K8  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cMDRWh  
httpConnection.setRequestProperty("User-Agent","NetFox"); Ia=_78MgZ  
k)`$%[K8  
!0Idp%  
int responseCode=httpConnection.getResponseCode(); `n 3FT=  
if(responseCode>=400) \F 3C=M@:  
{ S dIGU[fm  
processErrorCode(responseCode); j%pCuC&"  
return -2; //-2 represent access is error \ V6   
} }{ n\tzR  
+0]'| tF>  
g<fDY6jt  
String sHeader; WP5VcBC  
aZ`<PdA  
9nn>O?  
for(int i=1;;i++) /61by$E  
{ LGIalf*7  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());  ispkj'  
//Utility.log(in.readLine()); 0Tcz[$?  
sHeader=httpConnection.getHeaderFieldKey(i); 2;:lK":  
if(sHeader!=null) !\CG,Ek  
{ CN7 k?JO<  
if(sHeader.equals("Content-Length")) su&t7rJ  
{ #G3` p!"  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); .i$,}wtw  
break; ^8:VWJM  
} "H>.':c"+3  
} hG= k1T%=  
else [UMLx  
break; ?VB#GJ0M9  
} bA}Z0a  
} rO0ZtC{K  
catch(IOException e){e.printStackTrace ();} %c]nWR+/  
catch(Exception e){e.printStackTrace ();} ;a |`s  
t)9]<pN%  
[s~JceUyX  
Utility.log(nFileLength); *4t-e0]j@w  
wW-Ab  
q(IZJGb  
return nFileLength; :$=|7v  
} rFo\+//  
}sv!=^}BY3  
ejVdxVr\7  
//保存下载信息(文件指针位置) 5MxH)~VQoM  
private void write_nPos() WSQ[.C  
{ P/ci/y_1  
try{ Va7c#P?  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BRb\V42i;  
output.writeInt(nStartPos.length); 20aZI2sk`  
for(int i=0;i<nStartPos.length;i++) S?L#N  
{ Go1(@  
// output.writeLong(nPos); eJ)1K  
output.writeLong(fileSplitterFetch.nStartPos); %tV32l=  
output.writeLong(fileSplitterFetch.nEndPos); SB TPTb  
} :X_CFW  
output.close(); :r&iM b:Ra  
} wUoiXi09  
catch(IOException e){e.printStackTrace ();} ,9mgYp2  
catch(Exception e){e.printStackTrace ();} e 8,{|a  
} h3kaD  
CM9XPr  
|QVr `tE<  
//读取保存的下载信息(文件指针位置) Gzw@w{JBL  
private void read_nPos() A:eFd]E{(  
{ PL@~Ys0  
try{ FEF"\O|Q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); L}$z/jo  
int nCount = input.readInt(); /s:w^ g~  
nStartPos = new long[nCount]; &|b4\uj9  
nEndPos = new long[nCount]; )CLf;@1  
for(int i=0;i<nStartPos.length;i++) y;nvR6)  
{ daslaa_A  
nStartPos = input.readLong(); ca(U!T68  
nEndPos = input.readLong(); f^p^Y F+  
} EUy(T1Cl&&  
input.close(); xYI;V7  
} .n`( X#,*l  
catch(IOException e){e.printStackTrace ();} 6\4Z\82  
catch(Exception e){e.printStackTrace ();} l&L,7BX  
} @RGDhwS47  
CbOCk:,g5  
GRT] aw  
private void processErrorCode(int nErrorCode) 3pSj kS|?>  
{ 8Atq,GcG  
System.err.println("Error Code : " + nErrorCode); jH>8bXQqZ  
} &vkjmiAS  
;L~p|sF  
i@5 )` <?  
//停止文件下载 R_1qn  
public void siteStop() H_w%'v&  
{ l4vTU=  
bStop = true; 4(=kE>n}  
for(int i=0;i<nStartPos.length;i++) R4{-Qv#8 q  
fileSplitterFetch.splitterStop(); E1  |<Pt  
"_< 9PM1t  
8[zb{PRu  
} cJDd0(tD!  
} M-J<n>hl  
//负责部分文件的抓取 LL(|$}yW  
**FileSplitterFetch.java ZyI$M3{J  
*/ +j{Y,t{4  
package NetFox; eY,O@'"8`  
BLn_u,3  
$.rzc]s  
import java.io.*; Zw{MgoJ0Z  
import java.net.*; M0L&~p_F  
%2"J:0j  
E!J=8C.:  
public class FileSplitterFetch extends Thread { 8#X_#  
>2b`\Q*<  
rp's  
String sURL; //File URL pu9^e4B9  
long nStartPos; //File Snippet Start Position 7Xg?U'X  
long nEndPos; //File Snippet End Position ?Go!j?#a  
int nThreadID; //Thread's ID aD9q^EoEs  
boolean bDownOver = false; //Downing is over 3[d>&xk@$  
boolean bStop = false; //Stop identical @;iXp>&&  
FileAccessI fileAccessI = null; //File Access interface 6L9, 'Bg  
WOX}Sw"  
yZCX S  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException .[:VSM7T  
{ 8{0k0 &x  
this.sURL = sURL; :Q_3hK  
this.nStartPos = nStart; @gY\;[#.  
this.nEndPos = nEnd; tY+$$GSQj  
nThreadID = id; vXv;1T  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 [AS}RV  
} ]$A(9Pn"  
~ #PLAP3-  
IP3E9z_ L  
public void run() XNehPZYS  
{ -Z0+oU(?YE  
while(nStartPos < nEndPos && !bStop) T2FE+A]n9  
{ g(Yb^'X/  
*?t%0){  
i"r!w|j  
try{ 65TfFcQ<S  
URL url = new URL(sURL); &GhPvrxI?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M Hi8E9_O  
httpConnection.setRequestProperty("User-Agent","NetFox"); )Si2 u5  
String sProperty = "bytes="+nStartPos+"-"; YKZa$@fA?  
httpConnection.setRequestProperty("RANGE",sProperty); @1-F^G%p8  
Utility.log(sProperty); z6*<V5<7  
(JUZCP/\  
`P}9i@C  
InputStream input = httpConnection.getInputStream(); }V]R+%:w@  
//logResponseHead(httpConnection); !H@0MQ7  
g}x(hF  
:E&g%'1  
byte[] b = new byte[1024]; YXW%]Uy+  
int nRead; (MLwQiop  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) "V& I^YSc>  
{ |[$~\MU  
nStartPos += fileAccessI.write(b,0,nRead); 7f{=w, U  
//if(nThreadID == 1) \ZI'|Ad  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ;dR=tAf0$Q  
} ?D`T7KSe~D  
k*mt4~KLT8  
7zemr>sIh  
Utility.log("Thread " + nThreadID + " is over!"); 5jB* fIz  
bDownOver = true; UUc8*yU)  
//nPos = fileAccessI.write (b,0,nRead); NSQp< m  
} 0Ua%DyJ  
catch(Exception e){e.printStackTrace ();} ;30nd=  
} XH}'w9VynR  
} 9X$ma/P[  
a<~77~"4wn  
eHiy,IN  
//打印回应的头信息 O%8EZyu  
public void logResponseHead(HttpURLConnection con) 9(4&KZpK  
{ R?o$Y6}5  
for(int i=1;;i++) c!K]J  
{ *Hz^K0:8(  
String header=con.getHeaderFieldKey(i); V)(R]BK{  
if(header!=null) AlXNg!j;5K  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J aTp} #  
Utility.log(header+" : "+con.getHeaderField(header)); 457\&  
else kF"@Ngv.  
break; @#g<IBG=*  
} 6( CDNMzj  
} BZ!v%4^9  
;!!n{l$r'  
&-d&t` `  
public void splitterStop() 9H-|FNz?c  
{ %a+mk E  
bStop = true; G+UMBn  
} 6 5N~0t  
#X 52/8G  
j)C,%Ol  
} H,nec<Jp  
o%9*B%HO/  
{(U %i\F\  
/* /1mW|O>0  
**FileAccess.java ,I1 RV  
*//文件访问(定位,写) 0j"8@<  
package NetFox; }X*Riu7gk  
import java.io.*; D=m 'pL/pl  
#P l~R  
VXIP0p@  
public class FileAccessI implements Serializable{ z|EEVNFd&  
Sz- J y:j  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 p2Zo  
RandomAccessFile oSavedFile; 7Mb# O_eh  
long nPos; ~cTN~<{dq  
+_XzmjnDd  
.A sv%p[W  
public FileAccessI() throws IOException Lzu.)C@Amx  
{ ho##Z*O  
this("",0); )E@A0W  
} @=}YTtq  
r\qj!   
W`\R%>$H  
public FileAccessI(String sName,long nPos) throws IOException C{gyj}5  
{ v\m ]A1  
oSavedFile = new RandomAccessFile(sName,"rw"); Zjbc3 M5  
this.nPos = nPos; 3)\8%Ox  
oSavedFile.seek(nPos); MrZh09y  
} t2,A@2DU 2  
+ s- lCz  
):i&`}SY  
public synchronized int write(byte[] b,int nStart,int nLen) CC#;c1t  
{ d ,4]VE  
int n = -1; Ecd;<$tk  
try{ ,lZB96r0  
oSavedFile.write(b,nStart,nLen); ,AxdCT  
n = nLen; QUu}Xg:  
} G:~k.1y[  
catch(IOException e) &f ^,la  
{ \"X!2  
e.printStackTrace (); tjupJ*Rt  
} C:PMewn  
O3I8k\`  
:<}=e@/~|  
return n; >-H {Z{VDd  
} ?b(=1S\E'^  
?VP8ycm  
N5a*7EJv+  
} ?OkWe<:4  
sBr_a5QQ#  
vI>>\ .ED  
/* .zi_[  
**SiteInfoBean.java  o4|M0  
*/ E[/\7 v\  
package NetFox; SQX:7YF~  
RhncBKm*M  
Ney/[3 A  
public class SiteInfoBean { 8C*c{(4  
SHe49!RA'{  
8_{X1bj  
private String sSiteURL; //Site's URL Z'"tB/=W  
private String sFilePath; //Saved File's Path :]\([Q+a  
private String sFileName; //Saved File's Name eEuvl`&  
private int nSplitter; //Count of Splited Downloading File _d5QbTe  
"wNJ  
9I}-[|`u  
public SiteInfoBean() ,6-:VIHQ  
{//nSplitter的缺省值为5 Wk)OkIFR  
//default value of nSplitter is 5 7@D@ucL  
this("","","",5);  #"@|f  
} *MKO I'  
IZpP[hov  
G"h'_7  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) 03q 5e  
{ < jJ  
sSiteURL= sURL; 3yVMXK  
sFilePath = sPath; G3Z)Z) N  
sFileName = sName; %J+E/  
this.nSplitter = nSpiltter;  # 1OOU  
bbE!qk;hEP  
As'=tIro  
} 8X[:j&@  
j0oR) du  
F(>Np2oi6  
public String getSSiteURL() 4y|BOVl  
{ Sc;BCl{=|  
return sSiteURL; jIJ~QpNE  
} 6 (]Dh;gC  
fdFo#P  
hgPa6Kd  
public void setSSiteURL(String value) pR=@S>!|  
{ ].-1v5  
sSiteURL = value; 6^]+[q}3  
} y [}.yyye  
0XE4<U   
u_oaebOrpP  
public String getSFilePath() NPy&OcRl  
{ v[1aW v:  
return sFilePath; H#,W5EJzM  
} ekWD5,G  
*4\:8  
geru=7  
public void setSFilePath(String value) ]cHgleHQ  
{ )_YX DU  
sFilePath = value; 9X}10u:  
} ]_f_w 9]  
marQNZ  
D4eDHq  
public String getSFileName() Q /U2^  
{ $V -~Bu-  
return sFileName; gb[5&> (#  
} NcBIg:V\c  
f%][}NN)Xr  
6]K_m(F  
public void setSFileName(String value) %O|iE M  
{ Ag-(5:  
sFileName = value; 8\&X2[oAD  
} XO.jl"xu  
<? q?Mn  
*#,7d"6W5  
public int getNSplitter() n(1l}TJy  
{ J!dm-L  
return nSplitter; D+lAhEN  
} .s?L^Z^  
PxvyN_B#>  
L>jY.d2w=K  
public void setNSplitter(int nCount) ]C!gQq2'a  
{ u-QB.iQ+s  
nSplitter = nCount; ha]VWt%}  
} ]E5o1eeg  
} WlOmJtt4)  
|3(' N#|  
Ri<u/ ]oR"  
/* I fK,b*%  
**Utility.java &GpRI(OB/+  
*/ YL!P0o13r  
package NetFox; g];!&R-  
p_RsU`[  
>^u2cAi3[  
public class Utility { Snj'y,p[  
>FeX<L  
Cjn#00  
public Utility() h79}qU  
{ Ouk ^O}W6  
y8]B:_iU9  
Kg{+T`  
} is?{MJZ_  
?>7[7(|  
//线程睡眠 \"7*{L:  
public static void sleep(int nSecond) !z\h| wU+  
{ "{A(x }'Y4  
try{ C7]f*TSC4  
Thread.sleep(nSecond); S,88*F(<^q  
} &l}^iP'%!  
catch(Exception e) aC]$k'71  
{ /2&c$9=1  
e.printStackTrace (); wW Lj?;bx  
} u+9hL4  
} k R?qb6  
y6g&Y.:o  
//日志 >xN .F/[K  
public static void log(String sMsg) M[NV )q/)  
{ j * %  
System.err.println(sMsg); 'NWfBJm  
} &h}#HS>l  
iDpSj!x/_  
mVj9, q0  
public static void log(int sMsg) ./\@Km?  
{ y'3rNa]G1  
System.err.println(sMsg); /4yo`  
} sU=H&D99  
} D(~U6SR  
D, k6$`  
f[]dfLS"W  
/* _qF+tm  
**TestMethod.java P9R9(quI  
*/ '6DBs8>1  
package NetFox;  {y)=eX9  
 CT&|QH{  
b!+hH Hv:  
public class TestMethod { -M\<nx  
4j-Xi  
x[cL Bc<  
public TestMethod() A[B<~  
{ ///xx/weblogic60b2_win.exe u2tfF  
try{ lqy Qf$t  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); y#`tgJ:  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); v_yw@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); t$`r4Lb9/  
fileFetch.start(); &j;wCvE4+  
} ez7A4>/  
catch(Exception e){e.printStackTrace ();} R8K&R\  
%:i7s-0w  
;xy"\S]  
} [|v][Hwv  
\P[Y`LYL  
VMZMG$C  
public static void main(String[] args) n3WlZ!$  
{ aHD]k8 m z  
new TestMethod(); r-,%2y?  
} <]ox;-56  
} ldf\;Qk  
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