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http断点续传简单实现(java)

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/* CK2B  
**SiteFileFetch.java <O.Kqk* nq  
*/ gdl| ^*tc  
package NetFox; >L8?=>>?\  
import java.io.*; os[ZIHph  
import java.net.*; L~IE,4  
H#+\nT2m  
gc##V]OD  
public class SiteFileFetch extends Thread { @|BD|{k  
uG;?vvg>  
4:D:| r  
SiteInfoBean siteInfoBean = null; //文件信息Bean b6|Z"{TI _  
long[] nStartPos; //开始位置 &M[MEO`t8  
long[] nEndPos; //结束位置 )Nbc/nB$  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 _mXs4  
long nFileLength; //文件长度 %4,xx'`  
boolean bFirst = true; //是否第一次取文件 e8oKn&  
boolean bStop = false; //停止标志 f e|g3>/|  
File tmpFile; //文件下载的临时信息 >:2}V]/ ;  
DataOutputStream output; //输出到文件的输出流 6JSY56v  
P'sfi>A  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) s D_G)c  
public SiteFileFetch(SiteInfoBean bean) throws IOException b4 CF`BG  
{ RAV^D.  
siteInfoBean = bean; '@bJlJB9>  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); '99@=3AB:`  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); GzdRG^vN  
if(tmpFile.exists ()) fYB*6Xb,w  
{ .$Y? W<  
bFirst = false; oE1M/*myS  
read_nPos(); {SJsA)9:#  
} )B;M  
else +oZH?N4yaM  
{ b0 &  
nStartPos = new long[bean.getNSplitter()]; +Qs!Nhsq  
nEndPos = new long[bean.getNSplitter()]; C`NmZwL  
} =p q:m  
DVh)w}v  
<4c%Q)  
pA.._8(t  
} qp>N^)>  
4d`+CD C  
+"8}R~`!  
public void run() yAG+] r  
{ C',6%6P  
//获得文件长度 [/cIUQ  
//分割文件 .xl.P7@JJ  
//实例FileSplitterFetch +Rqbf  
//启动FileSplitterFetch线程 |c0,  
//等待子线程返回 4z_n4=  
try{ w>[T&0-N  
if(bFirst) &tj0M.-  
{ p x#suy  
nFileLength = getFileSize(); =IZ[_ /@  
if(nFileLength == -1) > aG=T{  
{ t`YWwI.  
System.err.println("File Length is not known!"); qnJ50 VVW  
} NEV p8)w  
else if(nFileLength == -2) _R^y\1Qu  
{ <7'&1= %r  
System.err.println("File is not access!"); 'wvMH;}u  
} mj2Pk,,SA  
else  ?Vc0)  
{ Uw)=WImz[  
for(int i=0;i<nStartPos.length;i++) CxDcY  
{ a9l8{ 3  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 8z}^jTM  
} AbfZ++aJ  
for(int i=0;i<nEndPos.length-1;i++) NYB "jKMk  
{ . I==-|  
nEndPos = nStartPos[i+1]; Vb!O8xV4;+  
} c -B/~&  
nEndPos[nEndPos.length-1] = nFileLength; /e1(? 20  
} oa`#RC8N  
} {DwIjy31T  
m#\[m<F  
,Dp0fauJ  
//启动子线程 !9]d |8!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ,lm=M 5b  
for(int i=0;i<nStartPos.length;i++) Z\ )C_p\-  
{ %;|0  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), d1]i,C~Y  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), H0>yi[2f  
nStartPos,nEndPos,i); f~ZEdq8  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); hw=GR_,  
fileSplitterFetch.start(); 89H sPB1"t  
} #jA)>z\Q^  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 1e}8LH7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 0<.R A%dj  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", "0Q1qZ  
nEndPos = " + nFileLength); (3;@^S4&w  
// fileSplitterFetch[nPos.length-1].start(); "=A>}q@;H  
% frfSGf.#  
HB iBv-=,  
//等待子线程结束 ho.(v;  
//int count = 0; a#[-*ou`  
//是否结束while循环 3FNT|QF  
boolean breakWhile = false; |=K_F3aJ  
"2{%JFE  
I ~$1Lu`~  
while(!bStop) 4W;S=#1  
{ (Rd$VYuf  
write_nPos(); gzdG6"  
Utility.sleep(500); obo&1Uv,/  
breakWhile = true; 80;n|nNB  
FTf<c0  
P^)q=A8Z#  
for(int i=0;i<nStartPos.length;i++) jc:s` 4  
{ \/5RL@X}  
if(!fileSplitterFetch.bDownOver) |+}G|hx@9  
{ lzhqcL"  
breakWhile = false; KzO,*M  
break; Eu,`7iQ?(  
} pqR\>d 0  
} 3BQ!qO17^d  
if(breakWhile) Q5a)}6-5  
break; yI3kvh  
u:dx;*  
d@ J a}`  
//count++; |E3X  
//if(count>4) ynwG\V  
// siteStop(); rs;r $  
}  P_Hv%g  
ig!7BxM)<h  
)rtomp:X  
System.err.println("文件下载结束!"); o:p *_>&  
} szmmu*F,U:  
catch(Exception e){e.printStackTrace ();} dl~|Izm  
} se9>.}zZN  
j !H^-d}q  
S\#17.=  
//获得文件长度 bC6oqF'#  
public long getFileSize() 9`B$V##-L  
{ T+IF}4e d  
int nFileLength = -1; /)L 0`:I#  
try{ rcN 9.1  
URL url = new URL(siteInfoBean.getSSiteURL()); (u1m]WYL  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~nY]o"8D  
httpConnection.setRequestProperty("User-Agent","NetFox"); }q[Bd  
>BVoHt~;  
e'9r"<>i  
int responseCode=httpConnection.getResponseCode(); }} ZY  
if(responseCode>=400) rS8 w\`_  
{ ~O6\6$3b5E  
processErrorCode(responseCode); nH-V{=**  
return -2; //-2 represent access is error $XnPwOj  
} >3.X?  
tJ0NPI56yP  
r 2:2,5_  
String sHeader; +^|iZbZKx  
 aSutM  
0<p{BL 8  
for(int i=1;;i++) R.9V,R5  
{ j2 %^qL  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); \cJa;WM>  
//Utility.log(in.readLine()); PkuTg";  
sHeader=httpConnection.getHeaderFieldKey(i); (5Nv8H8|  
if(sHeader!=null) +0l`5."d  
{ 2?q(cpsN  
if(sHeader.equals("Content-Length")) "sUyHt-&  
{  ti@kKz  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); /~p+j{0L3W  
break; =/0=$\Ws  
} {w6/[ -^  
} `Ityi}  
else .ic:`1  
break; OQ&'Dti  
} RP4Ku9hk  
} ~ 5"JzT  
catch(IOException e){e.printStackTrace ();} @OpNHQat9  
catch(Exception e){e.printStackTrace ();} /0MDISQy9  
*# {z3{+  
R:aa+MX(1  
Utility.log(nFileLength); V^s0fWa  
gb|Q%LS9R  
Xd `vDgD  
return nFileLength; WYcA8 X/  
} 5e8AmY8;  
}28=  
9LJZ-/Wq  
//保存下载信息(文件指针位置) c]k*}W3T  
private void write_nPos() _ QOZ sEe  
{ $.%rAa_H  
try{ Fg]?zEa  
output = new DataOutputStream(new FileOutputStream(tmpFile)); sBX-X$*N  
output.writeInt(nStartPos.length); ^Q<mV*~  
for(int i=0;i<nStartPos.length;i++) Wi. 5Y{  
{ t<iEj"5  
// output.writeLong(nPos); X;F8_+Np  
output.writeLong(fileSplitterFetch.nStartPos); I^\&y(LJF  
output.writeLong(fileSplitterFetch.nEndPos); a?h*eAAc.  
} &EGqgNl  
output.close(); (.Y/  
} 1 T<+d5[C  
catch(IOException e){e.printStackTrace ();} bPK Ow<  
catch(Exception e){e.printStackTrace ();} y] oaO+  
} PUJ2`iP1^3  
68fiG  
G"5D< ]  
//读取保存的下载信息(文件指针位置) Lo.rvt  
private void read_nPos() t&q N: J  
{ jEdtJ EPa  
try{ T4/fdORS  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); SMr13%KN/  
int nCount = input.readInt(); n{0Ld - zH  
nStartPos = new long[nCount]; W*DVi_\$y  
nEndPos = new long[nCount]; =<@2#E)  
for(int i=0;i<nStartPos.length;i++) ! |waK~jK  
{ ?4H#G)F  
nStartPos = input.readLong(); rf:XRJ <4  
nEndPos = input.readLong(); VXBY8;+Yp  
} pO  Iq%0]  
input.close(); eDI= nSo  
} 8LkP)]4^sO  
catch(IOException e){e.printStackTrace ();} IA zZ1#/3  
catch(Exception e){e.printStackTrace ();} W<ZK,kv  
} ^>x|z.  
qVqRf.-\  
g6t"mkMY L  
private void processErrorCode(int nErrorCode) /&#XhrT  
{ O4 3YY2  
System.err.println("Error Code : " + nErrorCode); $q?$]k|M`  
} Wm~` ~P  
lH^^77"4Qo  
%.v{N6  
//停止文件下载 p^kUs0$GS  
public void siteStop() 85:NFa@J  
{ %sBAl.!BN  
bStop = true; &.13dq  
for(int i=0;i<nStartPos.length;i++) s'aip5P  
fileSplitterFetch.splitterStop(); wFh8?Z3u_  
[D "t~QMr  
Y}*\[}l:&x  
} 'n QVj  
} o{b=9-V  
//负责部分文件的抓取 EJ}!F?o  
**FileSplitterFetch.java N]EcEM#  
*/ 1LJuCI=~  
package NetFox; gJiK+&8I  
vr^~yEr  
qLL,F  
import java.io.*; x&Vm!,%:1  
import java.net.*; AmPMY:1i"  
0kQPJWF  
AE`We$!  
public class FileSplitterFetch extends Thread { X[s8X!#  
]?1Y e8>Y<  
SnlyUP~P  
String sURL; //File URL Pz#7h*;cw.  
long nStartPos; //File Snippet Start Position 9Ya<My  
long nEndPos; //File Snippet End Position 1 2++RkL#  
int nThreadID; //Thread's ID up3O|lj4  
boolean bDownOver = false; //Downing is over -4rDbDsr  
boolean bStop = false; //Stop identical XfE?C:v   
FileAccessI fileAccessI = null; //File Access interface 1be %G [*  
1axQ)},o@p  
&c(WE RW?-  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $mmup|;(  
{ >h2%[j=  
this.sURL = sURL; uJHu>M}~  
this.nStartPos = nStart; iI@jZVk  
this.nEndPos = nEnd; 02`$OTKz  
nThreadID = id; .#u_#=g?  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 (6CN/A{qe  
} M2x["  
n,HE0Zn]Y_  
OH^N" L  
public void run() <e]Oa$  
{ {qW~"z*  
while(nStartPos < nEndPos && !bStop) f'Iz G.R  
{ .x`M<L#M(  
\;-fi.Hrf$  
XoL JL]+?  
try{ [ xOzzp4  
URL url = new URL(sURL); ;= j@, yu  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); I$NhXZ)KT  
httpConnection.setRequestProperty("User-Agent","NetFox"); EV#MQM  
String sProperty = "bytes="+nStartPos+"-"; tt?58dm|  
httpConnection.setRequestProperty("RANGE",sProperty); =~Ynz7 /x  
Utility.log(sProperty); )#a[-.OI  
JXG"M#{  
& gJV{V5Ay  
InputStream input = httpConnection.getInputStream(); ""Zp:8o  
//logResponseHead(httpConnection); ^J Z^>E~  
\ \BCcr\l  
~U(,TjJb  
byte[] b = new byte[1024]; Qu=LnGo~P  
int nRead; .6O"| Mqb  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ri`R<l8  
{ _LAS~x7,  
nStartPos += fileAccessI.write(b,0,nRead); HkV1sT  
//if(nThreadID == 1) IM$2VlC  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); w{~+EolK  
} ms($9Lv/  
nzjkX4KV  
O%1v) AT&\  
Utility.log("Thread " + nThreadID + " is over!"); ^JI o? R  
bDownOver = true; Q%/<ZC.Mz6  
//nPos = fileAccessI.write (b,0,nRead); ,\ 2a=Fp  
} ^l^fD t  
catch(Exception e){e.printStackTrace ();} Q6o(']0  
} R1F5-#?'E  
} {7!UQrm<  
`r5 $LaD  
87 }&`  
//打印回应的头信息 fP3_d  
public void logResponseHead(HttpURLConnection con) 6:U$w7P0 e  
{ AC O)Dt(Y  
for(int i=1;;i++) GV)<Q^9  
{ A^ _a3$,0  
String header=con.getHeaderFieldKey(i); !zPG? q]3  
if(header!=null) nA|.t  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); S[tE&[$(p  
Utility.log(header+" : "+con.getHeaderField(header)); nf 1#tlIJd  
else DjU9 uZT  
break; SVjl~U-^  
} Xi?b]Z  
} pE{yv1Yg  
)$w*V9d  
r'CM  
public void splitterStop() r1ws1 rr=  
{ wU#F_De)R:  
bStop = true; k>dsw:  
} bX.ja;;   
@i^~0A#q*  
p^(&qk?ut  
} Hk>79};  
2=?tJ2E  
^:9$@ +a  
/* > 0{S  
**FileAccess.java U yw-2]!n  
*//文件访问(定位,写) s5RjIa0$7  
package NetFox; pLMRwgzr  
import java.io.*; eI1GXQ%  
aNyvNEV3C  
oG$)UTzGc  
public class FileAccessI implements Serializable{ h._nK\  
k{gLMl  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 C^ Q tSha  
RandomAccessFile oSavedFile; 9}B`uJ  
long nPos; /(O$(35  
 g PAX4'  
[2ax>Yk$  
public FileAccessI() throws IOException s >0Nr  
{ [D5t{[i  
this("",0); 7_2kDDW0  
} <foCb%$(?  
%>gW9}kB  
#W.vX?-'0  
public FileAccessI(String sName,long nPos) throws IOException &z"krM]G  
{ j CTAKaq  
oSavedFile = new RandomAccessFile(sName,"rw"); +0),xu  
this.nPos = nPos; ~&\ f|%  
oSavedFile.seek(nPos); 6t/`:OZC:  
} SI:U0gUc  
&V>fYgui  
!v]b(z`Y  
public synchronized int write(byte[] b,int nStart,int nLen) %{6LUn  
{ OMwsbp&  
int n = -1; A:<;M@q !  
try{ X=8Y&#%  
oSavedFile.write(b,nStart,nLen); I\qYkWg7  
n = nLen; K[chjp!$l  
} pT?Q#,fh  
catch(IOException e) 0A{/B/r   
{ #YDr%>j  
e.printStackTrace (); nC {K$  
} g*w<*  
K78rg/`  
86f2'o+  
return n; CF|]e:  
} 6<0n *&  
;n\= R 5.  
Y!6/[<r$~k  
} s4_/&h  
?PTk1sB  
3]-_q"Co4f  
/* `nUO l  
**SiteInfoBean.java l"n{.aL  
*/ >;z<j$;F<  
package NetFox; PpLU  
[sW.CK= 3  
Og;-B0,A  
public class SiteInfoBean { EBtLzbj  
yfU<UQ!1  
Pmi#TW3X  
private String sSiteURL; //Site's URL /~4 "No@  
private String sFilePath; //Saved File's Path %!ebO*8q  
private String sFileName; //Saved File's Name b| SE<\  
private int nSplitter; //Count of Splited Downloading File K ~44i  
zi~5l#I  
?S?2 0  
public SiteInfoBean() }HEvr)v9  
{//nSplitter的缺省值为5 >zkRcm  
//default value of nSplitter is 5 @pGZLq  
this("","","",5); 7FN<iI&7\  
} W4;m H}#0  
gn5)SP8  
K;7f?52  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) o;b0m;~   
{ WWT",gio  
sSiteURL= sURL; Gu=STb  
sFilePath = sPath; E{HY!L[  
sFileName = sName; EkT."K  
this.nSplitter = nSpiltter; 5unG#szq  
g~UUP4<$"  
4h6k`ie!$  
} `RMI(zI3g.  
5-)#f?  
>hY" 3  
public String getSSiteURL() }AZc8o-  
{ 6io, uh!  
return sSiteURL; UZ8?[  
} -st7_3  
_ >` X]I;  
@v\*AYr'M  
public void setSSiteURL(String value) K.gEj*@  
{ @?C#r.vgp  
sSiteURL = value; * y^OV_n-8  
} ,2oF:H  
R~bC,`Bh  
, n !vsIN  
public String getSFilePath() a:~@CUD >I  
{ _w@qr\4i=  
return sFilePath; 7j5f ;O^+  
} s=?aox7  
Bh&Ew   
W"L&fV+3  
public void setSFilePath(String value) JcJmds  
{ ~_9"3,~o5  
sFilePath = value; (2?G:+C 7  
} W:i?t8y\y  
X5YiFLH>y\  
ThW,Y" l  
public String getSFileName() 1 4 LI5T  
{ *zO&N^X.4  
return sFileName; cYNJhGY  
} ,? E&V_5  
9>/wUQs!]  
HG/p$L*  
public void setSFileName(String value) =TR,~8Z|  
{ Gf8s?l  
sFileName = value; -{h   
}  Lw1T 4n  
K[ .JlIP  
,n2i@?NHZ  
public int getNSplitter() -#-p1^v}  
{ 4 !`bZ`_Bw  
return nSplitter; \EbbkN:D  
} Hy{ Q#fq  
$]aBe !  
Z?MoJ{.!?R  
public void setNSplitter(int nCount) x0a.!  
{ df+t:a  
nSplitter = nCount; P`U<7xF~  
} NV4g~+n  
} }4c o)B"  
4([.xT  
HEK-L)S. *  
/* l? #xAZx&_  
**Utility.java }aB#z<B6  
*/ #s5 pz8v  
package NetFox; Ju@Q6J5  
cIXwiC8t  
Kr  L>FI  
public class Utility { x4Rk<Th"o  
\(I6_a_{  
i5hD#  
public Utility() G@S&1=nj3  
{ WUAJjds  
fbZibcQ%k  
OH<?DcfeL  
} UVf\2\Y  
IL7`0cN(  
//线程睡眠 jW*1E *"  
public static void sleep(int nSecond) :ZdUx  
{ ~Pk0u{,4XQ  
try{ %R_{1GrL'c  
Thread.sleep(nSecond); m$>iS@R  
} =fc: 6JR  
catch(Exception e) ^ L:cjY/  
{ zH)_vW  
e.printStackTrace (); lQPqcZd  
} 4C~UcGMv\  
} " oy\_1|  
%XhfXd'  
//日志 Ft%hh|$5y  
public static void log(String sMsg) &UAe!{E0  
{ lp&!lb`  
System.err.println(sMsg); jyW[m,#(go  
} 1S%k  
"u}9@}*  
-237Lx$/  
public static void log(int sMsg) $%2_{m_K:p  
{ bv?0.{Z  
System.err.println(sMsg); OVoO6F ]  
} L^9HH)Jc  
} k/Mp6<?C:  
~M ?|Vn  
1`r| op},  
/* &j u-  
**TestMethod.java ,W5.:0Y;f[  
*/ c $;\i  
package NetFox; TmEY W<  
y93k_iq$S  
!MZw#=D`  
public class TestMethod { ateUpGM QU  
q/@dR{-  
[_DPxM=V  
public TestMethod() Xer@A;c  
{ ///xx/weblogic60b2_win.exe 7-iIay1h"  
try{ lhn8^hOJ/  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5);  :,]S}R  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); +KK$0pL  
SiteFileFetch fileFetch = new SiteFileFetch(bean); >POO-8Q  
fileFetch.start(); f~& a-  
} u'9gVU B  
catch(Exception e){e.printStackTrace ();} _&{%Wc5W~F  
D\L!F6taS  
Yt1mB[&f^  
} N} />rD  
8q_0,>w%  
H9"=  p  
public static void main(String[] args) oC dGQ7G}  
{ \4~AI=aw,T  
new TestMethod(); HR{s&ho  
} 1 0N,?a  
} B< ;==|  
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