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http断点续传简单实现(java)

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/* O /GD[9$i  
**SiteFileFetch.java Hiq9Jn uv(  
*/ K%Rx5 S  
package NetFox; ' rXkTm1{  
import java.io.*; 0z,c6MjM+  
import java.net.*; &^z~wJ,]  
G;tIhq[$Vb  
YAO.Ccz  
public class SiteFileFetch extends Thread { 44n^21k  
uD+;5S]us  
V57^0^Zp`  
SiteInfoBean siteInfoBean = null; //文件信息Bean z`/v}'d[X  
long[] nStartPos; //开始位置 lfCoL@$6D  
long[] nEndPos; //结束位置 ;KnnAZJ  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )[/+j"F   
long nFileLength; //文件长度 ov?>ALRg  
boolean bFirst = true; //是否第一次取文件 n0EKNMO  
boolean bStop = false; //停止标志 1W; +hXx  
File tmpFile; //文件下载的临时信息 Ex~OT  
DataOutputStream output; //输出到文件的输出流 inp=-  
;8U NM  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) `f b}cJUa  
public SiteFileFetch(SiteInfoBean bean) throws IOException &oAuh?kTq  
{ jtd{=[STU  
siteInfoBean = bean; i8 dv|oa  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); [t0gXdU 6  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 5~ jGF  
if(tmpFile.exists ()) m+1MoeR  
{ ^d!-IL_  
bFirst = false; >WDb89kC=  
read_nPos(); q~a6ES_lA  
} c.NAUe_3  
else '!Q[+@$  
{ 5<&<61[A  
nStartPos = new long[bean.getNSplitter()]; }mX;0qO  
nEndPos = new long[bean.getNSplitter()]; q7X /"Dfx  
} V-t!  
:^px1  
4Jht{#IIG  
A/ GEDG ?  
} ]x~H"<V  
QHA<7Wg  
rU(N@i%  
public void run() In]h+tG?rN  
{ YsDn?pD@  
//获得文件长度 {-H6Z#b[  
//分割文件 Rg' 1 F  
//实例FileSplitterFetch "bRck88V  
//启动FileSplitterFetch线程 #O G_O I  
//等待子线程返回 1!,lI?j,  
try{ HSyohP87  
if(bFirst) 84|Hn|4t  
{ D @T,j4o  
nFileLength = getFileSize(); qc@CV:  
if(nFileLength == -1) 5.idC-\  
{ E@t^IGD r  
System.err.println("File Length is not known!"); +\Rp N  
} MB:E/  
else if(nFileLength == -2) M]eH JZ~v  
{ `y m^0x8  
System.err.println("File is not access!"); o D^],  
} KeY)%{  
else Nqy',N  
{ $Nnz |y  
for(int i=0;i<nStartPos.length;i++) :Bda]]Y=  
{ trg+" )a  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); pbAQf3  
} YS/{q~$t  
for(int i=0;i<nEndPos.length-1;i++) w0VJt<e*  
{ Gv3a<Knn4  
nEndPos = nStartPos[i+1]; P|c79  
} ]w! x  
nEndPos[nEndPos.length-1] = nFileLength; 4RJ8 2yq-  
} fok OjTE  
} par $0z/  
91`biVZfA  
G+=&\+{#4  
//启动子线程 8la.N*  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; E WOn"   
for(int i=0;i<nStartPos.length;i++) &QLCij5:  
{ hG; NJx-=R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), F< Qjoaz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), wvsTP32]  
nStartPos,nEndPos,i); %<:?{<~wH9  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [sbC6(z  
fileSplitterFetch.start(); :,6dW?mun6  
} bvs0y7M='  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,??xW{* |  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); r(0I>|u  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Pa%XLn'5  
nEndPos = " + nFileLength); qFt%{~a S  
// fileSplitterFetch[nPos.length-1].start(); }yC ve  
nSmYa7  
t k2B\}6  
//等待子线程结束 =^O8 4Cp 6  
//int count = 0; 3]M YH b  
//是否结束while循环 Hk(w\   
boolean breakWhile = false;  &EV|knW  
*ofK|r  
 qqLmjDv  
while(!bStop) ok2$ p  
{ 'R99kL/.N  
write_nPos(); s>E4.0[I%  
Utility.sleep(500); G{$9e}#  
breakWhile = true; t&eY+3y,T  
4f'WF5S/}8  
 \^w=T*  
for(int i=0;i<nStartPos.length;i++) Ds$FO}KD{  
{ }|&M@Up  
if(!fileSplitterFetch.bDownOver) 7 8Nli/U  
{ i=]IUjx<  
breakWhile = false; CSR 6  
break; a:7"F{D91  
} ,`B*rCOa  
} >{$ ;O  
if(breakWhile) &(IL`%  
break; :Dw;RcZQ  
JP S L-j  
S\MD]>4  
//count++; O"nY4  
//if(count>4) LX!16a@SxA  
// siteStop(); \bZbz/+D  
} M +~guTh  
o#4Wn'E  
VEd\*  
System.err.println("文件下载结束!"); LPvyfD;Zy  
} *.~hn5Y|?  
catch(Exception e){e.printStackTrace ();} av&dGsFP  
} 9Or3X/:o  
`3*>tq  
w1h07_u;v  
//获得文件长度 *Iyv${  
public long getFileSize() Oh5(8.<y  
{ TJ ;4QL  
int nFileLength = -1; k;#$Oxa>t=  
try{ AW!|xA6'`:  
URL url = new URL(siteInfoBean.getSSiteURL()); L_=J(H|  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); > rB7ms/@E  
httpConnection.setRequestProperty("User-Agent","NetFox"); f8 B*D4R}  
2u~0B +)K/  
UW. F1)  
int responseCode=httpConnection.getResponseCode(); N|WnUlf]:  
if(responseCode>=400) x{&0:|bCs6  
{ P)tXU  
processErrorCode(responseCode); #B &D  
return -2; //-2 represent access is error 72@8M  
} {uDL"~^\  
ak;fCx&  
;yx+BaG~?  
String sHeader; cJGA5m/{I  
-~p@o1k0  
(TDLT^  
for(int i=1;;i++) 8n,i5>!d  
{ Z"mpE+U*  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); h,\^Sb5AP  
//Utility.log(in.readLine());  7=6p  
sHeader=httpConnection.getHeaderFieldKey(i); VQ$=F8ivG  
if(sHeader!=null) I,l%6oPa  
{ \4bma<~a  
if(sHeader.equals("Content-Length")) iS hB ^  
{ 0/#XUX 4  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 6jO*rseC  
break; |&o1i~Y  
} BB1'B-O  
} LrsP4G  
else `Z{; c  
break; EN+WEMro  
} ;#G>qo  
} o`DBzC  
catch(IOException e){e.printStackTrace ();} u> %r(  
catch(Exception e){e.printStackTrace ();} !-|&  
? Ls]k  
3|[:8  
Utility.log(nFileLength); ;KbnaUAS8  
w(k7nGU]  
X6N^<Z$  
return nFileLength;  4O[5,  
} tkR^dC  
FJ!N)`[  
&bRmr/D  
//保存下载信息(文件指针位置) ^8 AV#a  
private void write_nPos() "k"q)5c  
{ _g0 qpa  
try{ Ni"fV]'  
output = new DataOutputStream(new FileOutputStream(tmpFile)); W7O%.xP  
output.writeInt(nStartPos.length); \Nb6E&+  
for(int i=0;i<nStartPos.length;i++) s3uT:Xw3rW  
{ `g6ZhG:W  
// output.writeLong(nPos); /?9e{,\s  
output.writeLong(fileSplitterFetch.nStartPos); A&Ut:OiA  
output.writeLong(fileSplitterFetch.nEndPos); 0d9rJv}~  
} \@*cj8e  
output.close(); RIC'JLWQ  
} 9 /t}S6b{  
catch(IOException e){e.printStackTrace ();} hh|'Uq3  
catch(Exception e){e.printStackTrace ();} ZBJ.dK?Ky|  
} [A yq%MA  
P=KOw;bs  
h7~&rWb  
//读取保存的下载信息(文件指针位置) l9qq;hhGP,  
private void read_nPos() dG Qy=T:  
{ q~;P^i<Y  
try{ @Ys(j$U't  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Rdwr?:y(]  
int nCount = input.readInt(); &rq7;X  
nStartPos = new long[nCount]; 7`~h'(k  
nEndPos = new long[nCount]; KG4~t=J`  
for(int i=0;i<nStartPos.length;i++) !#f4t]FM`B  
{ n)sK#C-VA  
nStartPos = input.readLong(); z=?ainnKx  
nEndPos = input.readLong(); l!~8  
} ^X)U^Qd  
input.close(); o5BOe1_Pw  
} ~.VWrHC  
catch(IOException e){e.printStackTrace ();} &.K8c phj  
catch(Exception e){e.printStackTrace ();} jO3Q@N0_  
} j8hb  
rQ30)5^V|  
:* /<eT_  
private void processErrorCode(int nErrorCode) b3#c0GL  
{ :>F:G%(DK  
System.err.println("Error Code : " + nErrorCode); w^A8ZT0^7  
} |jEKUTv,G  
yXg783B|v  
yJ/m21f  
//停止文件下载 oT\B-lx  
public void siteStop() ;}.jRmnJ  
{ /+JCi6{sHS  
bStop = true; ag:#82C  
for(int i=0;i<nStartPos.length;i++) JBeC\ \QX  
fileSplitterFetch.splitterStop(); f$*M;|c1c/  
v?K X Tc%Z  
lU:z>gC  
} i._d^lR\t  
} K)_0ej~C  
//负责部分文件的抓取 =y0!-y  
**FileSplitterFetch.java U5dJ=G  
*/ y!blp>V6  
package NetFox; N95"dNZE  
U87VaUr  
[0m'a\YE9  
import java.io.*; o:f=dBmoX  
import java.net.*; h'MX{Wm.  
}1:jM_H)k  
feQ_dA q  
public class FileSplitterFetch extends Thread { o! sxfJKl  
k3sP,opacX  
$Z.c9rY1  
String sURL; //File URL unSF;S<  
long nStartPos; //File Snippet Start Position Q\m"n^XN  
long nEndPos; //File Snippet End Position &{Uaa  
int nThreadID; //Thread's ID bxrByu~|1  
boolean bDownOver = false; //Downing is over q/m}+v]  
boolean bStop = false; //Stop identical RNl%n}   
FileAccessI fileAccessI = null; //File Access interface nITr5$f  
va~:oA  
qW?^_  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException Vn=J$Uv0  
{ )Qw|)='-  
this.sURL = sURL; ln3x1^!  
this.nStartPos = nStart; (0Hhn2JA  
this.nEndPos = nEnd; _L%/NXu,  
nThreadID = id; 0:v7X)St  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 P:ys--$"  
} T/-PSfbkj  
o"7,CQye  
:3Ty%W&&  
public void run() {D1=TTr^  
{ 7QQ3IepP  
while(nStartPos < nEndPos && !bStop) bnB}VRal  
{ +&(sZFW5o  
b[e+(X  
I/XVo2Ee  
try{ <ywxz1i  
URL url = new URL(sURL); TD!QqLW  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); FRs5 Pb1  
httpConnection.setRequestProperty("User-Agent","NetFox"); d<`Z{"g NS  
String sProperty = "bytes="+nStartPos+"-"; {3_M&$jN  
httpConnection.setRequestProperty("RANGE",sProperty); dkG-Yz~  
Utility.log(sProperty); ,i>5\Yl%  
c6BaC@2  
*5*d8;@>  
InputStream input = httpConnection.getInputStream(); i]8zZRe  
//logResponseHead(httpConnection); yK{;72  
sAnStS=>  
J[VQ6fD%  
byte[] b = new byte[1024]; {BJ[h  
int nRead; dRWp/3 }  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) W5J"#^kdF8  
{ axXA y5  
nStartPos += fileAccessI.write(b,0,nRead); SV6Np?U  
//if(nThreadID == 1) +qzsC/y  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); MbY a6jrF  
} iOj mj0  
5OpK~f5  
Zt[ P kBi  
Utility.log("Thread " + nThreadID + " is over!"); )o AK)e  
bDownOver = true; pf] sL/g  
//nPos = fileAccessI.write (b,0,nRead); FjkE^o>  
} >"zSW?  
catch(Exception e){e.printStackTrace ();} s49 AF  
} w y:USS?  
} pBK[j ([  
> { fX;l  
o#%2N+w  
//打印回应的头信息 xjR/K&[m  
public void logResponseHead(HttpURLConnection con) L|!9%X0.  
{ ZiVTc/b  
for(int i=1;;i++) Ddt(*z /  
{ (Q#A Br8  
String header=con.getHeaderFieldKey(i); 89'nbg  
if(header!=null) M#F;eK2pf  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); h7gH4L!'u  
Utility.log(header+" : "+con.getHeaderField(header)); ;M@ /AAZ  
else 5:^dyF&sm{  
break; MFE~bU(h  
} Q'$aFl'NR  
} zzq/%jki  
?w3f;v  
z'fGHiX7.0  
public void splitterStop() t?YGGu^  
{ olK%TM[Y  
bStop = true; .hETqE`E  
} b*?="%eE(  
sNS! /  
!{Y$5)Xh`]  
} Hr96sN.R   
 "}Ya.  
el+euOV  
/* 7th&C,c&  
**FileAccess.java ~3/>;[!  
*//文件访问(定位,写) a/>={mb Ki  
package NetFox; urXM}^  
import java.io.*; Z^h'&c#  
'3%!Gi!g  
pX6OhwkTK  
public class FileAccessI implements Serializable{ d:<{!}BR3  
~w4aA<2Uq  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 9at7$Nq  
RandomAccessFile oSavedFile; . +.Y`0  
long nPos; r95$B6  
-I\_v*nA  
mIl^  
public FileAccessI() throws IOException bLaD1rnGi  
{ )oHIRsr  
this("",0); Q0ev*MS9Z  
} {[)J~kC+  
V `@@ufU}  
]2K>#sn-]  
public FileAccessI(String sName,long nPos) throws IOException `,\WhJ?9  
{ p]=8=pE<  
oSavedFile = new RandomAccessFile(sName,"rw"); 9dy"Y~c  
this.nPos = nPos; |l7e*$j  
oSavedFile.seek(nPos); )h>Cp,|{  
} [x-Z)Q. 5  
i"sVk8+o!  
C.pNDpx-  
public synchronized int write(byte[] b,int nStart,int nLen) "6Ly?'H K  
{ G8akMd]2  
int n = -1; $\m=-5 0-  
try{ y~p7&^FeR  
oSavedFile.write(b,nStart,nLen); F}i rCi47c  
n = nLen; Hsx`P  
} Z*s/%4On  
catch(IOException e) hMi!H.EX.  
{ f-4<W0%  
e.printStackTrace (); T5W r;a  
} IxgnZX4N  
K6!`b( v#  
BC!l)2  
return n; f85j?Jm  
} 1`B5pcuI  
z\fD}`^8  
|MTgKEsn  
} uR@\/6!@  
.^P^lQT]>  
m!E36ce}  
/* #r:J,D6*  
**SiteInfoBean.java (VwS 9:`  
*/ \p [!@d^  
package NetFox; _RY<-B   
LdVGFlcXi  
r")=Z1y  
public class SiteInfoBean { 9r\8  !R  
^ /:]HG  
)p12SGR5  
private String sSiteURL; //Site's URL =NyzX&H6  
private String sFilePath; //Saved File's Path @oYTJd(v{  
private String sFileName; //Saved File's Name >:Q:+R;3o  
private int nSplitter; //Count of Splited Downloading File s( 2=E|  
|~v($c  
j!:U*}f  
public SiteInfoBean() #@lr$^M  
{//nSplitter的缺省值为5 M}/%t1^g:  
//default value of nSplitter is 5 cGOE$nL  
this("","","",5); <Hm:#<\  
} = eTI@pN`  
+`.%aJIi9  
-+Quw2465^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) `C_#EU-  
{ 98o;_tU'  
sSiteURL= sURL; G?>~w[#mQR  
sFilePath = sPath; /i DS#l\0  
sFileName = sName; )k29mqa`  
this.nSplitter = nSpiltter; kD MS7y<s  
( 9dV%#G\  
v`x~O+  
} ^/Gjk  
Mk,8v],-Tj  
kDO6:sjR7  
public String getSSiteURL() ]DC]=F.  
{ Z2*hQ`eE  
return sSiteURL; wrGd40  
} ?R"5 .3  
/x-Ja[kL  
UkXc7D^jwm  
public void setSSiteURL(String value) f_.1)O'83  
{ $_)YrqSo~  
sSiteURL = value; Y k~ i.p  
} X]  Tb4  
`2r21rVntf  
h/-7;Csv  
public String getSFilePath() !dVcnK1  
{ R>pa? tQgK  
return sFilePath; \EB]J\ x<  
} h`3;^T  
)-9|3`  
uVOpg]8d  
public void setSFilePath(String value) ZpI_/  
{  _%i|*  
sFilePath = value; ufEt"P-X.  
} ']+H P9i$  
,u~\$ Az6  
Wc`Vcn1  
public String getSFileName() |a\s}M1  
{ 3%|<U51  
return sFileName; l*%voKZG  
} 4Z]^v4vb  
'*-X 3p  
=bv8W < #  
public void setSFileName(String value) S$muV9z2=  
{ mpr["C"l  
sFileName = value; :GL|:  
} 5\QNGRu"  
-@^SiI:C  
UxzwgVT  
public int getNSplitter() ]e?*7T]  
{ r OB\u|Pg  
return nSplitter; YWq[)F@0G  
} i1aS2gFi_  
}zLe;1Tx  
%$sWNn  
public void setNSplitter(int nCount) pR\etXeLd  
{ \I'A:~b)L  
nSplitter = nCount; WYaDN:kZf  
} 3UrqV`x \  
} *'exvY~  
?kS5=&<  
cpE&Fba}"  
/* wQ [2yq  
**Utility.java !lu$WJ{M  
*/ Z|wZyt$$  
package NetFox; *+@/:$|U  
7*[>e7:A  
/I6?t= ?<  
public class Utility { hk,Q=};  
?cg+RNI  
If4YqBG  
public Utility() M6DyOe<  
{ G9V zVx#T#  
CqrmdWN  
cRU.   
} ]/d2*#  
T 6phD8#  
//线程睡眠 v8pUt\m"  
public static void sleep(int nSecond) jl:O~UL6i  
{ /9GqEQsfM  
try{ c+4SGWmO  
Thread.sleep(nSecond); ]$*N5Y  
} NPS=?5p>  
catch(Exception e) (G$m}ng  
{ 4r5,kOFWb  
e.printStackTrace (); z': >nw  
} x!"!oJG^k  
} *FG@Dts^&  
_B W$?:)9  
//日志 MX9 q )(:  
public static void log(String sMsg) * =;=VUu5  
{ OpH9sBnA  
System.err.println(sMsg); UdLC]  
} G.oaDGy  
E,C<ox4e  
7Uj[0Awn  
public static void log(int sMsg) jj$'DZk  
{ x$s#';*  
System.err.println(sMsg); _=}Y lR  
} v3]q2*`G#  
} E176O[(V=  
d3n TJX  
gNZ^TeT  
/* 1p8E!c{}j  
**TestMethod.java %FF  S&vd  
*/ 5#2vSq!H  
package NetFox; u\t ;  
C($`'~b  
wbr"z7}  
public class TestMethod { .3HC*E.e  
PfuYT_p4s  
0tsll1  
public TestMethod() 4|:{apH  
{ ///xx/weblogic60b2_win.exe W tzV|e,  
try{ b]Z@zS<8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #lct"8  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?W(wtp,o  
SiteFileFetch fileFetch = new SiteFileFetch(bean); wh~~g qi9  
fileFetch.start(); m?M(79u[  
} VVe>}  
catch(Exception e){e.printStackTrace ();} F;~ #\ X  
k)4|%  
*dKA/.g  
}  j, G/[V  
YJ75dXc&&  
-k<.Q=]<t  
public static void main(String[] args) @*2FG\c<  
{ =6+BBD  
new TestMethod(); G: @gO2(D  
} 4&$G;?#W2  
} Ws1<Jt3/."  
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