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http断点续传简单实现(java)

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/* ]@_M)[ x  
**SiteFileFetch.java RGh `=D/yE  
*/ (cJb/|?3  
package NetFox; GY 4?}T^s  
import java.io.*; MB;< F  
import java.net.*;  N)G.^9  
\tE2@  
n}X)a-=  
public class SiteFileFetch extends Thread { 9^l_\:4  
8 &:  *<  
bv ,_7UOG  
SiteInfoBean siteInfoBean = null; //文件信息Bean 4L\bT;dQ|.  
long[] nStartPos; //开始位置 $$`E@\5P  
long[] nEndPos; //结束位置 i2`i5&*  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 "mr;|$Y  
long nFileLength; //文件长度 i3g;B?54  
boolean bFirst = true; //是否第一次取文件 9NLO{kN  
boolean bStop = false; //停止标志 e#]=-^  
File tmpFile; //文件下载的临时信息 ](c[D9I!8  
DataOutputStream output; //输出到文件的输出流 SOQm>\U'i  
8 St`,Tq)  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) +Z[(s!  
public SiteFileFetch(SiteInfoBean bean) throws IOException /~*U'.V  
{ aY7kl  
siteInfoBean = bean; P [-2^1P"  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 5\/h3 i"I  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); j;@7V4'  
if(tmpFile.exists ()) l<0 BMwS8  
{ LQ pUyqR  
bFirst = false; *+TIF"|1  
read_nPos(); U&#1qRm\h  
} +*-u_L\'  
else Q?rb(u(  
{ C=2"*>lTn  
nStartPos = new long[bean.getNSplitter()]; 4Sv&iQ=vh  
nEndPos = new long[bean.getNSplitter()]; ,p6X3zY  
} [X[d`@rXv  
k r2V  
|u,2A1  
7Fb |~In<Z  
} tn};[r  
K| #%u2C  
0kP, Zj<  
public void run() &qqS'G*  
{ Uv'.]#H<  
//获得文件长度 GW a_^  
//分割文件 "QA <5P  
//实例FileSplitterFetch sxcpWSGA^  
//启动FileSplitterFetch线程 bAv>?Xqa  
//等待子线程返回 O.4ty)*  
try{ (m|w&oA/  
if(bFirst) SA s wP  
{ xh Sp<|X_  
nFileLength = getFileSize(); tj@IrwC^e"  
if(nFileLength == -1) 5at\!17TY  
{ ;i|V++$_  
System.err.println("File Length is not known!"); +FiM?,G  
} /N(L52mz  
else if(nFileLength == -2) diN5*CF'~  
{ _ h\wH;  
System.err.println("File is not access!"); %9hzz5#  
} o(5Xj$Z  
else JJlwzH  
{ ;7CE{/Bq.p  
for(int i=0;i<nStartPos.length;i++) D/C,Q|Ya6  
{ y1P KoN|K  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); `iuo([E d  
} }ybveZxv5A  
for(int i=0;i<nEndPos.length-1;i++) Fa78yY+6  
{ #MYhKySku  
nEndPos = nStartPos[i+1]; T1yJp$yD"  
} qXmkeidb&W  
nEndPos[nEndPos.length-1] = nFileLength; $8#zPJR&  
} A\J|eSG'$  
} !DFT}eu  
yAO Ye"d  
@Q~Oc_z  
//启动子线程 b}63?.M{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; xJ H]>#XJ  
for(int i=0;i<nStartPos.length;i++) ><9E^ k0.  
{ {iiHeSD  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), jeM %XI  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), n |5+HE4@  
nStartPos,nEndPos,i); 4r5trquC  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !IlsKMZ  
fileSplitterFetch.start(); a!YpSFr  
}  mD`v>L  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), <}x_F)E[t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); e glcf z%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", tpp. 9  
nEndPos = " + nFileLength); =9@{U2 =l  
// fileSplitterFetch[nPos.length-1].start(); !}fq%8"-  
t>;u;XY!;  
>-fOkOWXy  
//等待子线程结束 !_<zK:`-L  
//int count = 0; Ig*68M<  
//是否结束while循环 xu[6h?u(h8  
boolean breakWhile = false; 8/cD7O  
Y(QLlJ*)/  
Ia-`x/r*m  
while(!bStop) E'qGKT  
{ >g8H  
write_nPos(); v:0.  
Utility.sleep(500); ~_^#/BnAl  
breakWhile = true; k fS44NV  
0 =#)-n  
h6c0BmS{1  
for(int i=0;i<nStartPos.length;i++) t3%[C;@wB  
{ # T_m|LN 7  
if(!fileSplitterFetch.bDownOver) B ^>}M  
{ .: ~);9kj  
breakWhile = false; RL0,QC)e#@  
break; GZgu1YR  
} z/zUb``  
} r}ZL{uWMW  
if(breakWhile) O!#yP Sq?  
break; >R "]{y  
mD @#,B7A  
F&? &8.  
//count++; fW^\G2Fk  
//if(count>4) NUH;\*]8s  
// siteStop(); ,{=pFs2  
} c zTr_>  
wWV`k  
oGz-lO{lt  
System.err.println("文件下载结束!"); ge*(w{|x  
} +RLHe]9&  
catch(Exception e){e.printStackTrace ();} \[</|]'[  
} =ZdP0l+V=k  
7!.#:+rg5#  
/.!ytHw8  
//获得文件长度 o'nju.'  
public long getFileSize() _ZUtQ49  
{ Y] Q=kI  
int nFileLength = -1; NYopt?Xg  
try{ !bEy~.  
URL url = new URL(siteInfoBean.getSSiteURL()); oCD#Gmr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); `uL^!-  
httpConnection.setRequestProperty("User-Agent","NetFox"); ~Y=v@] 2/  
yhnhORSY;  
6 6S I  
int responseCode=httpConnection.getResponseCode(); E#'JYz@  
if(responseCode>=400) zq ;YE  
{ ^~iu),gu  
processErrorCode(responseCode); >jI( ^8?  
return -2; //-2 represent access is error \va'>?#o1  
} (' yBIb\ue  
MVe:[=VOT|  
1&\ A#  
String sHeader; Fy(-.S1  
|#hj O3  
GF(<!PC  
for(int i=1;;i++) @lvvI<U  
{ I9JiH,+  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); o/ Z  
//Utility.log(in.readLine()); &fH;A X.  
sHeader=httpConnection.getHeaderFieldKey(i); tNsiokOm  
if(sHeader!=null) <\i}zoPO  
{ vU5a`0mH  
if(sHeader.equals("Content-Length")) Af'L=0  
{ p9c`rl_N  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ID+ o6/V8  
break; r3.A!*!  
} M[aF3bbN  
} 1eiV[z$?  
else IK#W80y  
break; "`Y.N$M`k  
} ~fL:pVp  
} (J!FW(Ma|=  
catch(IOException e){e.printStackTrace ();} Mf [v7\  
catch(Exception e){e.printStackTrace ();} '9O4$s1  
u~kfz*hz  
(sX=#<B%  
Utility.log(nFileLength); & w%%{lM  
RY8Ot2DWi  
46U?aHKW@|  
return nFileLength; "M e)'  
} k 4|*t}o7  
$nX4!X  
$F> #1:=v<  
//保存下载信息(文件指针位置) _ ," -25a  
private void write_nPos() cE}y~2cH  
{ ]xJ5}/  
try{ fb8"hO]s  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 6]`XW 0{C  
output.writeInt(nStartPos.length); kGaK(^w  
for(int i=0;i<nStartPos.length;i++) QL_~E;U  
{  {@XzY>  
// output.writeLong(nPos); (?luV#{5  
output.writeLong(fileSplitterFetch.nStartPos); vAeh#V~#  
output.writeLong(fileSplitterFetch.nEndPos); ]#)1(ZE  
} RPH]@  
output.close(); Ps<6kQ(  
} !Db 0r/_:G  
catch(IOException e){e.printStackTrace ();} -Fi{[%&u  
catch(Exception e){e.printStackTrace ();} n%N|?!rB  
} tCkKJ)m  
vn5X]U"  
HTfHAc?W  
//读取保存的下载信息(文件指针位置) Z^P]-CB|6A  
private void read_nPos() :wlX`YW+e  
{ B.:DW3  
try{ kzZdYiC  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); N*d )<8_  
int nCount = input.readInt(); {Pi+VuLE  
nStartPos = new long[nCount]; }B-@lbK6)  
nEndPos = new long[nCount];  ;'^5$q  
for(int i=0;i<nStartPos.length;i++) EN OaC  
{ `jl 1Q,~2r  
nStartPos = input.readLong(); irqNnnMGEa  
nEndPos = input.readLong(); cQ:Y@f 9  
} r3OTU$t?  
input.close(); 'g3!SdaLF  
} Fbvw zZ  
catch(IOException e){e.printStackTrace ();} S1_X@[t  
catch(Exception e){e.printStackTrace ();} xR9<I:^&  
} NF/@'QRT  
^F5Q(A  
+59tX2@Q  
private void processErrorCode(int nErrorCode) p([g/Q  
{ e|ChCvk  
System.err.println("Error Code : " + nErrorCode); cP >MsUZWl  
} &4g]#A>@  
('SA9JG  
'o%IA)sF  
//停止文件下载 [&IJy  
public void siteStop()  bnll-G|  
{ z|';Y!kQ  
bStop = true; `5VEGSP]  
for(int i=0;i<nStartPos.length;i++) ~d+.w%Z `  
fileSplitterFetch.splitterStop(); yJ(BPSt  
>U.)?>G/dt  
E=Z;T   
} P!;%DI!<b  
} SV-M8Im73z  
//负责部分文件的抓取 QG~4 <zy  
**FileSplitterFetch.java *} yOL [  
*/ :n1^Xw0q  
package NetFox; ?Hb5<,1u3  
p&Os5zw;|  
D{%l 4og  
import java.io.*; }3G`f> s  
import java.net.*; /h/f&3'h  
+`;YK7o  
UODbT&&  
public class FileSplitterFetch extends Thread { fpCkT[&m  
} Mh@%2$  
O<A$,<67  
String sURL; //File URL Qktj  
long nStartPos; //File Snippet Start Position _;o)MTw|'  
long nEndPos; //File Snippet End Position cc LTA  
int nThreadID; //Thread's ID O$'BJKj-4  
boolean bDownOver = false; //Downing is over ?*2DR:o>@  
boolean bStop = false; //Stop identical v'x)AbbC  
FileAccessI fileAccessI = null; //File Access interface ^lF'KW$  
s7x&x;-  
'X()|{  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 0nz=whS{  
{ U"Gg ,  
this.sURL = sURL; HnDz4eD  
this.nStartPos = nStart; i_ha^mq3  
this.nEndPos = nEnd; p};B*[ki  
nThreadID = id; [| \Z"   
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -k$*@Hq  
} 5>E]C=maD  
B%~hVpm,eM  
5xHP5+&  
public void run() WtT* 1Z  
{ z>\vYR$  
while(nStartPos < nEndPos && !bStop) "OIra2O  
{ ||M;[-JoJ  
}8H_^G8  
/dT7:x*  
try{ n^HKf^]  
URL url = new URL(sURL); M Y2=lT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); a>3#z2#  
httpConnection.setRequestProperty("User-Agent","NetFox"); O WJv<3  
String sProperty = "bytes="+nStartPos+"-"; U Bo[iZ|%  
httpConnection.setRequestProperty("RANGE",sProperty); F\!Va  
Utility.log(sProperty); G5C=p:o{/  
L7~9u|7a#  
utH,pGs C.  
InputStream input = httpConnection.getInputStream(); Y[(U~l,a+  
//logResponseHead(httpConnection); hJkP_( +J\  
SN${cs%  
C}i1)   
byte[] b = new byte[1024]; .3yoDab  
int nRead; /| nZ)?  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop)  b7]MpL  
{ 0j =xWC  
nStartPos += fileAccessI.write(b,0,nRead); <{t*yMr   
//if(nThreadID == 1) f!|$!r*q  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ?9Lp@k~TO  
} P^wDt14>  
y:C=Ni&,"  
]c67zyX=%  
Utility.log("Thread " + nThreadID + " is over!"); D*!UB5<>/t  
bDownOver = true; !$q *~F"S  
//nPos = fileAccessI.write (b,0,nRead); cO&(&*J r  
} 4,nUCT  
catch(Exception e){e.printStackTrace ();} V^v?;f?  
} f WUFCbSU  
} z5V~m_RO  
RDX$Wy$@L  
_TGv"c@V  
//打印回应的头信息 Q1cM{$}M  
public void logResponseHead(HttpURLConnection con) !x%$xC^Iz  
{ yvQRr75  
for(int i=1;;i++) NCid`a$  
{ i!|OFU6  
String header=con.getHeaderFieldKey(i); 5<Lal^c D  
if(header!=null) 4[& L<D6h  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); J )*7JX  
Utility.log(header+" : "+con.getHeaderField(header)); E41ay:duAl  
else )<<}8Fs  
break; i4Ps#R_wx  
} " R=,W{=  
} #i t)  
K!L0|W H%!  
^lI>&I&1  
public void splitterStop() }K rQPg  
{ ,Q7W))j  
bStop = true; C0 RnBu  
} `$fKS24u  
lhp.zl  
^V5VRGq  
} JemB[  
\dB)G<_  
,V>7eQt?  
/* bL6, fUS  
**FileAccess.java w &b?ze{  
*//文件访问(定位,写) :u ruC  
package NetFox; I(bxCiRV  
import java.io.*; `vMrlKq  
AW\#)Em  
>j%4U*  
public class FileAccessI implements Serializable{ <i!:{'%  
MBjo9P(  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 E1"H( m&6  
RandomAccessFile oSavedFile; Xb/W[rcs  
long nPos; R&!{3!V  
)0tq&  
w1N-`S:  
public FileAccessI() throws IOException nQHQVcDs8  
{ 54^2=bp  
this("",0); OG!+p}yD]  
} zfm-v U  
t,v=~LE  
[k<w'n*  
public FileAccessI(String sName,long nPos) throws IOException JSCZX:5  
{ ,`su0P\%#.  
oSavedFile = new RandomAccessFile(sName,"rw"); :S_3(/} \  
this.nPos = nPos; 40M/Gu:  
oSavedFile.seek(nPos); $-J=UT2m  
} x2_?B[z  
oiKY2.yW  
n[`KhRN  
public synchronized int write(byte[] b,int nStart,int nLen) D.ajO^[  
{ ?gGmJl  
int n = -1; HW"';M%  
try{ &3_S+.JO  
oSavedFile.write(b,nStart,nLen); ^! r<-J  
n = nLen; J+]W*?m  
} P c'0.4  
catch(IOException e) :JI&ngWK  
{ )W0zu\fL =  
e.printStackTrace (); =KCAHNr4?  
} Vs:x3)m5j  
 mRYM,   
/Y7Yy jMi  
return n; ~4}'R_  
} 8b!-2d:*  
:wR aB7  
YU (|i}b  
} C5ia9LpRX  
k2@|fe  
?Z{:[.  
/* :5 zXW;s  
**SiteInfoBean.java {0?]weN*  
*/ M{   
package NetFox; t:N3k ;k  
UbDRE[^P  
$HE ?B{  
public class SiteInfoBean { {i!@C(M3  
%aHQIoxg  
9NPOdt:@  
private String sSiteURL; //Site's URL % a9C]?  
private String sFilePath; //Saved File's Path ymr#OP$<S  
private String sFileName; //Saved File's Name RY\[[eG  
private int nSplitter; //Count of Splited Downloading File ! ,v!7I  
,|Xibfw  
{ d*?O  
public SiteInfoBean() 4^>FN"Ve`B  
{//nSplitter的缺省值为5 7c7:B2Lq  
//default value of nSplitter is 5 !#' y#  
this("","","",5); P+/6-CJ  
} )=EJFQ*v  
!92zC._  
Scfk] DT  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) # 1#?k  
{ fd CN?p[_  
sSiteURL= sURL; Ac,Qj`'V  
sFilePath = sPath; Ga9^+.j  
sFileName = sName; 7L"Pe'Hw  
this.nSplitter = nSpiltter; ta)'z@V@g  
!}$,) ~<+H  
HT@/0MF{J  
} 0)Wrfa  
/CT g3Q"KQ  
8<w8"B.i  
public String getSSiteURL() A@HCd&h  
{ >i:h dcxe  
return sSiteURL; G|,'6|$jE  
} F/(z3Kf  
g~Hmka_fD1  
sm1(I7y  
public void setSSiteURL(String value) %Q2<bj]  
{ iAWd 9x  
sSiteURL = value; __Tg1A  
} qyl9#C(a  
/"LcW"2;N  
d0"Xlle ld  
public String getSFilePath() 54geU?p0  
{ x,~ys4  
return sFilePath; =yy7P[D  
} OY?x'h  
]!=,8dY  
0**.:K<i  
public void setSFilePath(String value) \A'tV/YAd  
{ D$OUy}[2`.  
sFilePath = value; WXgGB[x  
} bf2B  
cf7UV6D g  
hCX_^%  
public String getSFileName() < `/22S"  
{ fZ6"DJZ  
return sFileName; 1p%75VW  
} (='e9H!3D  
ra[*E4P9L*  
#rs]5tx([  
public void setSFileName(String value) b+rn:R  
{ I_\#(  
sFileName = value; (tLAJ_v!.K  
} )kl(}.9X  
@9X+ BdQU  
'U8% !  
public int getNSplitter() o7A+O%dX  
{ oTjsiXS  
return nSplitter; ;xKPa6`E  
} WU" Lu  
ha -KfkPFE  
=Co[pt  
public void setNSplitter(int nCount) q0a8=o"|  
{ I\FBf&~  
nSplitter = nCount; =8!FY"c*  
} Munal=wL  
} 3gcDc~~=  
d2!A32m  
B{^ojV;]m  
/* G7yR&x^  
**Utility.java e71dNL'$  
*/ bWe_<'N  
package NetFox; ]?$e Bbt  
PAUepO_  
{"x>ewAf  
public class Utility { {|Pg]#Wi&  
\F }s"#  
+ yF._Ie=  
public Utility() P nxxW?  
{ R | &+g\{;  
MMYV8;c  
Oz: J8l%  
} #,4CeD|(D,  
^G~C#t^  
//线程睡眠 },;ymk|g[  
public static void sleep(int nSecond) A3Lfh6O  
{ jZ5 mpYUO  
try{ K\2UwX  
Thread.sleep(nSecond); 5,,b>Z<  
} F ^mMyK  
catch(Exception e) cp&- 6 w+  
{ @-ms_Z  
e.printStackTrace (); NPFrn[M$  
} :nPLQqXGQ  
} pg4J)<t#  
*NEA(9  
//日志 \`!M5FJ  
public static void log(String sMsg) \>%.ktG  
{ F.%g_Xvk:  
System.err.println(sMsg); =%\y E0#  
} !4blX'<w  
i3s,C;7[2  
L#|, _j=9  
public static void log(int sMsg) yl#(jb[?1  
{ 5^}"Tn4I  
System.err.println(sMsg); ycr\vn t  
} T/$6ov+K  
} Z^ e?V7q  
I\|x0D  
n> >!dg Og  
/* wy1xZQ<5  
**TestMethod.java X4D>  
*/ 8!T6N2O6d  
package NetFox; aUBGp: (  
f.~-31  
wj'5D0   
public class TestMethod { tsLi5;KA]  
_^;;vR%   
\U0p?wdr:  
public TestMethod() >\x   
{ ///xx/weblogic60b2_win.exe <Kq4thR  
try{ O$2'$44HX  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ZMI!Sl  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5);  YXdd=F  
SiteFileFetch fileFetch = new SiteFileFetch(bean); w[A$bqz   
fileFetch.start(); `h:$3a:5  
} J'%  
catch(Exception e){e.printStackTrace ();} <DM /"^*  
OjUZ-_J  
&f:"p*=a\  
} '4L0=G:A<q  
2[#7YWs  
(eOzntp8  
public static void main(String[] args) ,Qd;t  
{ 4Hk eXS.  
new TestMethod(); <yxEGjm  
} =xa:>Vh#  
} |Zn |?#F  
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