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http断点续传简单实现(java)

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/* !7]4sXL{  
**SiteFileFetch.java uW },I6g  
*/ Y1vl,Yi  
package NetFox; 9l5l"Wj&  
import java.io.*; ^(r?k_i/  
import java.net.*; L&H 4fy!>  
|f# ~#Y2v  
CXwDG_e  
public class SiteFileFetch extends Thread { 6lpfk&  
7g^=   
<nOK#;O)  
SiteInfoBean siteInfoBean = null; //文件信息Bean ,IX:u1mO  
long[] nStartPos; //开始位置 Ii_X^)IL(  
long[] nEndPos; //结束位置 fH-V!QYGF  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 TL lR"L5  
long nFileLength; //文件长度  A M8bem~  
boolean bFirst = true; //是否第一次取文件 o|F RG{TJ  
boolean bStop = false; //停止标志 J39,x=8LL  
File tmpFile; //文件下载的临时信息 WLqwntzk  
DataOutputStream output; //输出到文件的输出流 %{Ez0XwGCn  
S7vT=  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) [Dni>2@0  
public SiteFileFetch(SiteInfoBean bean) throws IOException u2,V34b-  
{  Gqvj  
siteInfoBean = bean; l6IpyIex  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); BuII|j  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Nz %{T  
if(tmpFile.exists ()) ~ x- R78'  
{ `'H"|WsT  
bFirst = false; {B8W>>E  
read_nPos();  K6d9[;F  
} (P&~PJH  
else -*t4(wT|j  
{ AX! YB'm-  
nStartPos = new long[bean.getNSplitter()]; Uax[Zh[Cg  
nEndPos = new long[bean.getNSplitter()];  [R:\  
} `],'fT|,S  
K"B2 SsC  
\q(DlqTqs  
H}5zKv.T  
} {fW(e?8)  
/X>Fn9 mM  
/2Q@M>  
public void run() m08:EX P  
{ u?6L.^Op  
//获得文件长度 gx~79;6  
//分割文件 {U/a h2*  
//实例FileSplitterFetch 0 UdAF  
//启动FileSplitterFetch线程 # Un>g4>Rh  
//等待子线程返回 :I*G tq   
try{ |d =1|C%,  
if(bFirst) 'i#m%D`dt  
{ '_!j9A]g  
nFileLength = getFileSize(); #/!fLU@  
if(nFileLength == -1) !.9pV.~  
{ }#va#Nb(,  
System.err.println("File Length is not known!"); #-?C{$2I  
} $J}d6%   
else if(nFileLength == -2) @y?<Kv}s  
{  &0! f_  
System.err.println("File is not access!"); 4Rj;lAlwB  
} s}yJkQb  
else #~<cp)!3  
{ %6rMS}  
for(int i=0;i<nStartPos.length;i++) ,[fn? s r  
{ Nb;xJSlox  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); l,5<g-r V  
} l+g\xUP  
for(int i=0;i<nEndPos.length-1;i++) A<-Prvryt  
{ +iKs)s_~  
nEndPos = nStartPos[i+1]; r;m_@*]  
} V8AF;1c?-'  
nEndPos[nEndPos.length-1] = nFileLength; CZaUrr  
} evOy Tvc  
} qOOF]L9r%u  
{hYH4a&Hb  
4pNIsjl}  
//启动子线程 1UG5Q-  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; p4mlS  
for(int i=0;i<nStartPos.length;i++) -XNjyXm2  
{ {KkP"j'7h  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V}<Hx3!  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), P>q"P1&{  
nStartPos,nEndPos,i); `\!oY;jk  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R&Mv|R   
fileSplitterFetch.start(); .<ux Z  
} )c~1s  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), /HCd52  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); rw> X JE  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", IO/%X;Y_  
nEndPos = " + nFileLength); 9gFb=&1k  
// fileSplitterFetch[nPos.length-1].start(); pdCn98}%-  
&%3$zgvR  
Fl)p^uUtl  
//等待子线程结束 f%r0K6p  
//int count = 0; [>+}2-#  
//是否结束while循环 V^Gz7`^  
boolean breakWhile = false; Th1/Bxb:  
15PFnk6E|  
l"9.zPvT<  
while(!bStop) qbu>YTj  
{ }py6H[  
write_nPos(); [X>\!mt  
Utility.sleep(500); $@]tTz;b  
breakWhile = true; _m3}0q  
ch2Qk8  
H(f~B<7q  
for(int i=0;i<nStartPos.length;i++) rzmd`)g  
{ (pY'v /a-  
if(!fileSplitterFetch.bDownOver) FtBYPSGz  
{ "{a-I=s\C  
breakWhile = false; Vy*&po[   
break; X; $g7A  
} 0}'  
} m|mY_t  
if(breakWhile) V/%tFd1  
break; :W]IJ mI\  
HzADz%~  
\;w$"@9  
//count++; ^H]q[XFR  
//if(count>4) F3k]*pk8w  
// siteStop(); d) V"tSC,  
} NyHHK8>  
Z:F5cXt<  
%C&HR2  
System.err.println("文件下载结束!"); `LD#fg*  
} 8S;]]*cD~  
catch(Exception e){e.printStackTrace ();} ;O8Uc&:P  
} m e\S:  
G)qNu}  
:=J~t@  
//获得文件长度 w[g(8 #*  
public long getFileSize() yO@KjCv"  
{ m~KGB"  
int nFileLength = -1; w]n ,`r^  
try{ ,SEC~)L  
URL url = new URL(siteInfoBean.getSSiteURL()); G/Ll4 :  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B+e$S%HV  
httpConnection.setRequestProperty("User-Agent","NetFox"); u$T`Bn  
3&*_5<t\X  
"YIrqk  
int responseCode=httpConnection.getResponseCode(); \;"$Z 9W  
if(responseCode>=400) Bvbv~7g (  
{ z'cK,psq(  
processErrorCode(responseCode); }jj@A !N  
return -2; //-2 represent access is error S@Rw+#QE  
} -w8c;5X  
\5g7_3,3W  
%;5AF8#c  
String sHeader; ^T}6o Ud  
&zVF!xNy&  
*.g0;\HF  
for(int i=1;;i++) B o@B9/ABv  
{ }1EfyR  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); UzLe#3MU  
//Utility.log(in.readLine()); JzhbuWwF-  
sHeader=httpConnection.getHeaderFieldKey(i); :Ja]Vt  
if(sHeader!=null) dV{N,;z  
{ M>Y ge~3  
if(sHeader.equals("Content-Length")) 1$cX` D`  
{ D9OI ",h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); "wk~[>  
break; u_0&`zq  
} &[]0yNG  
} Fi8'3/q-^  
else OKDBzl  
break; Vq7L:,N9  
} &r0b~RwUv  
} ~N</;{}fL4  
catch(IOException e){e.printStackTrace ();} L%D:gy9o  
catch(Exception e){e.printStackTrace ();} eBZ^YY<*g  
hdFIriE3  
m%8idjnG  
Utility.log(nFileLength); -#yLH  
eK }AVz}k  
vfW  
return nFileLength; *0 y|0J+ 0  
} }=kf52Am,}  
=M]f7lJ  
D@[Mk"f  
//保存下载信息(文件指针位置) d1=kHU4_9  
private void write_nPos() !1MSuvWP  
{ MGUzvSf  
try{ 7 S^iGe  
output = new DataOutputStream(new FileOutputStream(tmpFile)); +-=o16*{ !  
output.writeInt(nStartPos.length); p h[ ^ve  
for(int i=0;i<nStartPos.length;i++) 3U#z {%  
{ \/8 I6a=  
// output.writeLong(nPos); 9v7l@2/  
output.writeLong(fileSplitterFetch.nStartPos); *G{%]\s?  
output.writeLong(fileSplitterFetch.nEndPos); ?t LJe  
} h> K~<BAz'  
output.close(); IvLo&6swW  
} CTu#KJ?j  
catch(IOException e){e.printStackTrace ();} }F=+*-SYZ  
catch(Exception e){e.printStackTrace ();} a<CN2e_Z  
} "^A4!.  
fJ!i%</V  
d8 1u  
//读取保存的下载信息(文件指针位置) x"kc:F  
private void read_nPos() uo`O$k<;  
{ bv&A)h"S  
try{ }t4?*:\  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fFG, ^;7-O  
int nCount = input.readInt(); `N 0Mm7  
nStartPos = new long[nCount]; 'n> ,+,&  
nEndPos = new long[nCount]; L4th 7#  
for(int i=0;i<nStartPos.length;i++) ]fH U/%  
{ "*o54z5"  
nStartPos = input.readLong(); y( M-   
nEndPos = input.readLong(); e/@tU'$  
} )9sRDNr  
input.close(); & i,on6  
} i#I+   
catch(IOException e){e.printStackTrace ();} hdB.u^!  
catch(Exception e){e.printStackTrace ();} ?`+46U%  
} P.bBu  
klC;fm2C  
["|' f  
private void processErrorCode(int nErrorCode) `I$'Lp#5  
{ =3rPE"@,[  
System.err.println("Error Code : " + nErrorCode); oiP8~  
} \I r&&%  
y~)rZ-eSB  
Eq>3|(UT  
//停止文件下载 w_30g6tA  
public void siteStop() ]w!gv /;  
{ =2HR+  
bStop = true; }]w/`TF  
for(int i=0;i<nStartPos.length;i++) N>z<v\`  
fileSplitterFetch.splitterStop(); b2;+a(  
k/+-Tq;  
u|m>h(O  
} tB"amv  
} ZKKz?reM'  
//负责部分文件的抓取 G{*m] 0Q  
**FileSplitterFetch.java bH}6N>Fp  
*/ +^% y&8e  
package NetFox; ns_5|*'  
!6_lD 0  
:>gzWVE<  
import java.io.*; dI!x Ai  
import java.net.*; @=o1q=5@8  
Q9X7- \n  
bSmF"H0cP  
public class FileSplitterFetch extends Thread { FY%v \`@1*  
i3I'n*  
XGE:ZVpW  
String sURL; //File URL g0ec-  
long nStartPos; //File Snippet Start Position @NMFurm  
long nEndPos; //File Snippet End Position p"4i(CWGS  
int nThreadID; //Thread's ID k$</7 IuH  
boolean bDownOver = false; //Downing is over ra \Moy  
boolean bStop = false; //Stop identical mG[S"?C  
FileAccessI fileAccessI = null; //File Access interface  j I  
tjZ.p.IlG  
%)[mbb  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException %MyA;{-F6  
{ @MIBW)P<  
this.sURL = sURL; jRN*W2]V  
this.nStartPos = nStart; 0ra VC=[  
this.nEndPos = nEnd; UkrqHHpy  
nThreadID = id; W69 -,w/  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 l,Un7]*  
} JpN]j`  
EL+6u>\- k  
%V-\|cw   
public void run() &.ZW1TxE8  
{ D$g|f[l  
while(nStartPos < nEndPos && !bStop) $M\|zUQu.  
{ iTgGf  
j""I,$t  
)5Yv7x(K  
try{ Z5juyzj  
URL url = new URL(sURL); 7sECbbJT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 5Cxh >,k  
httpConnection.setRequestProperty("User-Agent","NetFox"); "Y@rNmBj  
String sProperty = "bytes="+nStartPos+"-"; &Im{p7gf!b  
httpConnection.setRequestProperty("RANGE",sProperty); ")|3ZB7>*  
Utility.log(sProperty); m7X&"0X  
j:D@X=|  
QC.WR'.  
InputStream input = httpConnection.getInputStream(); p2}$S@GD  
//logResponseHead(httpConnection); <,qJ% kc  
dzDh V{  
ia15r\4j)  
byte[] b = new byte[1024]; <{@?c  
int nRead; )@.bkzW  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) Tyu]14L  
{ 7kU:91zR  
nStartPos += fileAccessI.write(b,0,nRead); Ko6 tp9G  
//if(nThreadID == 1) Z qX  U  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); fq/F| c  
} %]%.{W\j3  
\&\_[y8U  
v{Cts3?Br  
Utility.log("Thread " + nThreadID + " is over!"); }$u]aX<  
bDownOver = true; 0S@O]k)  
//nPos = fileAccessI.write (b,0,nRead); \KfngYD]W  
} \3dM A_5  
catch(Exception e){e.printStackTrace ();} KZO!  
} ~Nf0 1,F  
} \dj&4u3  
AfKJa DKf  
~[XDK`B  
//打印回应的头信息 2<}^m/}  
public void logResponseHead(HttpURLConnection con) v 1Yf:c  
{ cSCO7L2E18  
for(int i=1;;i++) .58>KBj(  
{  FRI<A8  
String header=con.getHeaderFieldKey(i); $Ch!]lJA  
if(header!=null) 8[(eV.  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); E> Ukxi1  
Utility.log(header+" : "+con.getHeaderField(header)); )t={+^Xe  
else kvs^*X''Ep  
break; \&]M \  
} Db\.D/ 76  
} 2%0z PflT  
v :]y#y  
7uJy<O  
public void splitterStop() kXS_:f;M  
{ lZCvH1&"  
bStop = true; Nj||^k  
} LNml["   
p,}-8#K[  
^_3idLE  
} x!bFbi#!"  
?KpHvf'  
!o~% F5|t  
/* V1Dwh@iS  
**FileAccess.java (:E_m|00;  
*//文件访问(定位,写) y %Get  
package NetFox; %)*!(%\S*3  
import java.io.*; W"4E0!r  
{EbR =  
)hj77~{ +  
public class FileAccessI implements Serializable{ ,(Fo%.j  
SQ5SvYH  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 /_v5B>  
RandomAccessFile oSavedFile; !zLd ,`  
long nPos; s$6zA j!  
dluNA(Xc-  
T8>:@EL-k  
public FileAccessI() throws IOException |$Dt6{h  
{ h8 >7si  
this("",0); u7G@VZ Ux5  
}  'vj45b  
L?&+*|VxI  
.Tt \U  
public FileAccessI(String sName,long nPos) throws IOException k\|G%0Jw  
{ <aa# OX  
oSavedFile = new RandomAccessFile(sName,"rw"); Nkn0G _  
this.nPos = nPos; 4q[C' J  
oSavedFile.seek(nPos); E+V^5Z:u  
} rklr^ e  
3;~1rw=$<  
x*}j$n(Oa  
public synchronized int write(byte[] b,int nStart,int nLen) {YWj`K  
{ S%uH*&`  
int n = -1; sR,]eo<p&  
try{ qu BTRW9  
oSavedFile.write(b,nStart,nLen); Lx,"jA/  
n = nLen; l5Z=aW Q  
} 0!veLXeK!  
catch(IOException e) zkn K2e,$  
{ AuUT 'E@E  
e.printStackTrace (); w_pEup\`  
} 4>>{}c!nf  
'|&}rLr:+  
w{)*'8oCB  
return n; f!ehq\K1k  
} 3  8pw  
kW\=Z 1\#  
?XL[[vyr  
} Ya*lq! u  
lxj_ (Uo  
nH}api^0A  
/* b>;>*'e  
**SiteInfoBean.java QE84l  
*/ (G<"nnjK  
package NetFox; N72z5[..  
85$MHod}[,  
pBiC  
public class SiteInfoBean { [J\5DctX;c  
9_ JK.  
'VFxg,  
private String sSiteURL; //Site's URL *CA|}l  
private String sFilePath; //Saved File's Path l"RX`N@In  
private String sFileName; //Saved File's Name H`]nY`HYg  
private int nSplitter; //Count of Splited Downloading File hJ.XG<?]$  
vmJ1-<G4*  
~6.AE/ow  
public SiteInfoBean() fF[n?:VV  
{//nSplitter的缺省值为5 |TF,Aj   
//default value of nSplitter is 5 \D?6_ ,O  
this("","","",5); f}^}d"&F  
} 3!Zd]1$  
^~-i>gTD  
&WN4/=QW-J  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) ]0by6hQ  
{ cf1Ve\(YGI  
sSiteURL= sURL; .3qaaXeH  
sFilePath = sPath; suj? e6  
sFileName = sName; 3ag*dBbs  
this.nSplitter = nSpiltter; 'e02rqip{  
HKv:)h{ ?  
QW6F24  
} l -_voOP  
QX ishHk&  
v3Tr6[9  
public String getSSiteURL() f3lFpS  
{ <i^Bq=E<rJ  
return sSiteURL; N\=pH{  
} 5!}xl9D  
pA"x4\s   
|4YDvDEJi  
public void setSSiteURL(String value) :N\*;>  
{ !cE>L~cza  
sSiteURL = value; kLR4?tX!  
} @YdS_W  
.a:"B\B`  
\E9Z H3;  
public String getSFilePath() Zw| IY9D  
{ 6(sqS~D  
return sFilePath; yU\&\fD>j  
} \MsAdYR  
.oH0yNFX  
u@}((V  
public void setSFilePath(String value) T=:O(R1*0  
{ \:8~na+(  
sFilePath = value; /tc*jXB  
} dn$1OhN8M  
p&B98c  
&zlwV"W  
public String getSFileName() UA>~xJp=  
{ 6/hY[a!  
return sFileName; i&-g 0  
} @}!1Uk3ud  
{#: js  
upQ:C>S  
public void setSFileName(String value) T.d+@ZV<#  
{ Q7&Yy25   
sFileName = value; uaNJTob  
} {\ P$5O{%  
W)1)zOD  
apa~Is1  
public int getNSplitter() 7S7gU\qOj  
{ /S$p_7N  
return nSplitter; <(6@l@J|6  
} vI{JBWE,S  
W tnZF]1:u  
.UakO,"z  
public void setNSplitter(int nCount) 1s-k=3)  
{ x6* {@J&5*  
nSplitter = nCount; kCL)F\v"iT  
} T_\HU*\  
} N)lzX X  
$@FD01h.t3  
2JYp.CJv  
/* 4wX{N   
**Utility.java mwZesSxB_  
*/ XPd>DH(Yc  
package NetFox; `i8osX[&p  
eU1= :n&&\  
nj!)\U  
public class Utility { ~7Kqc\/H&I  
r*N:-I~z  
=#&K\  
public Utility() ?xGxr|+a  
{ 4 `Z@^W  
pB@8b$8(Z  
}.3F|H  
} _J}ce  
L=iaL[zdJ  
//线程睡眠 +)^F9LPl  
public static void sleep(int nSecond) A5!j rSyv  
{ :J@q Xa  
try{ muQH!Q  
Thread.sleep(nSecond); 8js5/G+  
} Z=sy~6m+v  
catch(Exception e) $R2T)  
{ ta> g:  
e.printStackTrace (); Dp6]!;kx  
} gd]vrW'wj  
} 2*vOo^f  
VjtI1I  
//日志 }IC$Du#  
public static void log(String sMsg) r[vMiVb  
{ X, <&#l  
System.err.println(sMsg); W=j/2c/  
} wp-5B= #:{  
)pjd*+V  
;o,t *  
public static void log(int sMsg)  $Tfq9  
{ Vl{CD>$,  
System.err.println(sMsg); y<m{eDV7  
} S6B(g_D|  
} k;3Bv 6  
=$}P'[V  
b=9(gZ 9  
/* |VB}Kv  
**TestMethod.java }9R45h}{<  
*/ nZfTK>)A0  
package NetFox; l$z[Vh^UU<  
Ms<^_\iPN  
 .LEQ r)  
public class TestMethod { Bz_['7D  
1.o-2:]E  
s{NEP/QQJ  
public TestMethod() p)f OAr  
{ ///xx/weblogic60b2_win.exe >@[`,  
try{ qBpv[m  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [@ "H2#CQ  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); ?;0=>3p*0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); g:q+.6va"  
fileFetch.start(); n>Y3hY  
} RsIEY5Q  
catch(Exception e){e.printStackTrace ();} Q nDymVF  
q =b.!AZy  
/_rQ>PgSZW  
} (s %T1 8  
i92{N$*x  
&jl'1mZ  
public static void main(String[] args) :@wO' o  
{ iH9g5G`O  
new TestMethod(); $ N5VoK  
} k)'hNk"x  
} iv?'&IUfK  
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