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http断点续传简单实现(java)

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/* m Y%PG  
**SiteFileFetch.java s'K0C8'U  
*/ wPG3Ap8L  
package NetFox; !J6k\$r  
import java.io.*; Crey}A/N  
import java.net.*; 'vCFT(C-  
b9\=NdyCY  
lR-4"/1|y  
public class SiteFileFetch extends Thread { 8`*`4m  
r<b g->lX  
i@g6%V=  
SiteInfoBean siteInfoBean = null; //文件信息Bean sjzZl*GSy  
long[] nStartPos; //开始位置  kU#$  
long[] nEndPos; //结束位置 P|64wq{B8  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5$O@+W!?@  
long nFileLength; //文件长度 I/'jRM  
boolean bFirst = true; //是否第一次取文件 ?EtK/6dJZt  
boolean bStop = false; //停止标志 4l z9z>J.V  
File tmpFile; //文件下载的临时信息 ,Ma$:6`f  
DataOutputStream output; //输出到文件的输出流 {cG&l:-r  
;,IGO7R  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) _/PjeEm $p  
public SiteFileFetch(SiteInfoBean bean) throws IOException `@Qq<T}V  
{ p-Q1abl  
siteInfoBean = bean; W;hI[9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); r?[Zf2&  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); wRWN]Vo  
if(tmpFile.exists ()) vmk c]DC  
{ y|1-,u.$  
bFirst = false; #&$4tTl  
read_nPos(); i*F^;-q)  
} 3tgct <"  
else tF=96u_X  
{ Qy9#(596  
nStartPos = new long[bean.getNSplitter()]; OvQG%D}P=  
nEndPos = new long[bean.getNSplitter()]; 'jfI1 ]q  
} uS<&$J H  
X\flx~  
JZai{0se  
'5{gWV`  
} m@TU2  
eLl ;M4d  
jg2>=}  
public void run() 8vchLl#  
{ (Kx3:gs  
//获得文件长度 i5:fn@&  
//分割文件 "|&SC0*  
//实例FileSplitterFetch 5 kQC  
//启动FileSplitterFetch线程 sx|=*j,_  
//等待子线程返回 ZfIQ Fh>  
try{ g9 g &]  
if(bFirst) j1>1vD-`T  
{ Wny{qj)=  
nFileLength = getFileSize(); ?HU(0Vgn'  
if(nFileLength == -1) iao_w'tJ  
{ Y2Y/laD  
System.err.println("File Length is not known!"); ?L7z\b"_~  
} q?JP\_o:  
else if(nFileLength == -2) hXZk$a'  
{ Xo$(zGb  
System.err.println("File is not access!"); ^F_c'  
} 7eZ,; x  
else 6J-tcL*4"%  
{ ~|+   
for(int i=0;i<nStartPos.length;i++) [_CIN  
{ w 8T#~Dc  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); 91[(K'=&  
} UKn>.,  
for(int i=0;i<nEndPos.length-1;i++) @_0XK)pW  
{ (i&:=Bfn)  
nEndPos = nStartPos[i+1]; Lw2EA 5  
} "y#$| TMB  
nEndPos[nEndPos.length-1] = nFileLength; l8jm7@.E  
} JrS|Ib)6  
} _sx]`3/86  
$Z$BF  
Br;1kQ%eC  
//启动子线程 yA =#Ji  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; rr9N(AoxW  
for(int i=0;i<nStartPos.length;i++) KN_3]-+B  
{ U H `=  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), }zj_Pp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  w8$8P  
nStartPos,nEndPos,i); qK,rT*5=  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Me2%X>;  
fileSplitterFetch.start(); ?>DN7je  
} {0QNqjue  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mM!Gomp  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); 4Bs '5@  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", kp LDK81I  
nEndPos = " + nFileLength); tVFl`Xr   
// fileSplitterFetch[nPos.length-1].start(); lfK sqe"  
oyK'h9Wt1  
<U$x')W  
//等待子线程结束 <Y9e n!3\  
//int count = 0; GK~uoz:^O  
//是否结束while循环 "V}WV!w  
boolean breakWhile = false; |!,;IoZ  
&r do Mc;  
X8"4)IZ3  
while(!bStop) Z`T]jm-3  
{ 2old})CLJ  
write_nPos(); ^e1@o\]  
Utility.sleep(500); /&_$+Iun  
breakWhile = true; cY0NQKUk~  
VMXccT9i!  
b<n*wH  
for(int i=0;i<nStartPos.length;i++) kq8.SvIb  
{ gwm!Pw j  
if(!fileSplitterFetch.bDownOver) @j=:V!g2O  
{ T]HeS(  
breakWhile = false; ))66_bech  
break; kc-=5l  
} ,K 8R%B  
} h'jc4mu0  
if(breakWhile) "m4. _4U  
break; <Z5-?wgf9  
j4k\5~yzS  
gF# HNv  
//count++; Py y!B  
//if(count>4) 3K!(/,`  
// siteStop(); S6Y2(qdP  
} T\?$7$/V  
.o8Sy2PaV  
?I{L^j^#4  
System.err.println("文件下载结束!"); 9sG]Q[:.]  
} xy))}c%  
catch(Exception e){e.printStackTrace ();} >J*x` a3Q  
} ct`j7[  
rP|~d}+I  
#9zpJ\E  
//获得文件长度 y)vK=,"  
public long getFileSize() /#jH #f[  
{ 6I2` oag  
int nFileLength = -1; eu={6/O  
try{ `Y O(C<r-  
URL url = new URL(siteInfoBean.getSSiteURL()); Pm&hv*D  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); : e1kpQ  
httpConnection.setRequestProperty("User-Agent","NetFox"); V^Y'!w\LGI  
2[j(C  
UE8j8U'L  
int responseCode=httpConnection.getResponseCode(); @GUlw[vi  
if(responseCode>=400) ZP{<f~;  
{ +`,;tz=?  
processErrorCode(responseCode); `>)[UG!:|  
return -2; //-2 represent access is error 2Pow-o*r  
} )G#mC0?PV  
/| q .q  
ysapvQN_6  
String sHeader; VWq]w5oQO  
' _d4[Olu  
5EU~T.4C<  
for(int i=1;;i++) 7UIf   
{ {Y-~7@  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 0FSNIPx  
//Utility.log(in.readLine()); "i#aII+T  
sHeader=httpConnection.getHeaderFieldKey(i); % IHIXncv[  
if(sHeader!=null) "!+gA&  
{ {ETM >  
if(sHeader.equals("Content-Length")) Z _Wzm!:  
{  J3`0i@  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); }@eIO|  
break; Hz\@#   
} m/z,MT74*J  
} w 5 yOSz  
else u 3^pQ6Q  
break; b9-IrR4h  
} nr2 Q[9~  
} _Jy7` 4B.  
catch(IOException e){e.printStackTrace ();} F~q(@.b  
catch(Exception e){e.printStackTrace ();} 1U% /~  
{{jV!8wK  
 ^M{,{bG  
Utility.log(nFileLength); JIhEkY  
AbxhNNK  
z',Fa4@z  
return nFileLength; DQT'OZ :w  
} [\AOr`7  
 0j_kK  
c/Xg ARCO  
//保存下载信息(文件指针位置) rtS' 90`  
private void write_nPos() l+[:Cni  
{ R&9FdM3K`:  
try{ lD[37U!  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Fvf |m7  
output.writeInt(nStartPos.length); ~: {05W  
for(int i=0;i<nStartPos.length;i++) M@#T`aS  
{ 9.8%Iw  
// output.writeLong(nPos); vfc:ok1  
output.writeLong(fileSplitterFetch.nStartPos); s3HVX'   
output.writeLong(fileSplitterFetch.nEndPos); -8xf}v~u  
} Wl |5EY  
output.close(); As<B8e]  
} +x(#e'6p  
catch(IOException e){e.printStackTrace ();} R*:>h8  
catch(Exception e){e.printStackTrace ();} [% C,&h5  
} s bj/d~$N  
H T|DT  
Keozn*fzI  
//读取保存的下载信息(文件指针位置) 'C/yQvJ  
private void read_nPos() ;xZjt4M1  
{ @(Y!$><Is  
try{ 6$6QAW0+f  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); ;eN ^'/4A  
int nCount = input.readInt(); &W,jR|B  
nStartPos = new long[nCount]; yEq7ueJ'  
nEndPos = new long[nCount]; TG%B:^Yz!  
for(int i=0;i<nStartPos.length;i++) ;%9]G|*{  
{ T1]?E]m{  
nStartPos = input.readLong(); 7Ml4u%?  
nEndPos = input.readLong(); h:nybLw?  
} fC[za,PXaE  
input.close(); EHk\Q\  
} Gq^vto  
catch(IOException e){e.printStackTrace ();} H_X^)\oJ  
catch(Exception e){e.printStackTrace ();} B1V{3  
} ovdJ[bO  
hbJ>GSoZ,  
z5kAf~A  
private void processErrorCode(int nErrorCode) }5-w,m{8/  
{ nN\H'{Wzd  
System.err.println("Error Code : " + nErrorCode); 9@lWI  
} KNUK]i&L  
m[^lu1\wn  
;f =m+QXU  
//停止文件下载 <eoie6@3  
public void siteStop() |^6{3a  
{ dE7S[O  
bStop = true; ^U }k   
for(int i=0;i<nStartPos.length;i++) x@t?7 o\&  
fileSplitterFetch.splitterStop(); z3Q&O$5\  
.\n` 4A1z  
+n)n6} S  
} "2l`XH  
} @1MnJP  
//负责部分文件的抓取 )S caT1I  
**FileSplitterFetch.java p+;& Gg54  
*/ %{@Q7  
package NetFox; FQ]/c#J  
zaqX};b  
fSkDD>&  
import java.io.*; >?, Zn  
import java.net.*; ;]u9o}[ 2  
wI$ a1H  
{FNkPX  
public class FileSplitterFetch extends Thread { ?, S/>SP  
DN*5q9.  
=~B"8@B  
String sURL; //File URL CMXF[X)%  
long nStartPos; //File Snippet Start Position AcC &Q:g  
long nEndPos; //File Snippet End Position aQCu3T  
int nThreadID; //Thread's ID ieFl4hh[G  
boolean bDownOver = false; //Downing is over o4);5~1l  
boolean bStop = false; //Stop identical .T| }rB<c  
FileAccessI fileAccessI = null; //File Access interface 0zaK&]oY0  
A&Y5z[p  
;mkkaW,D*  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException iwotEl0*{  
{ ,`@pi@<"#  
this.sURL = sURL; 7?$?Yu  
this.nStartPos = nStart; R4m {D  
this.nEndPos = nEnd; 5*AXL .2ih  
nThreadID = id; Zt`Tg7m  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 i[v4[C=WB!  
} hF%M!otcJ-  
qt@L&v}~j  
KK){/I=z  
public void run() Fx9-A8oIR  
{ E/P~HE{  
while(nStartPos < nEndPos && !bStop) O>~,RI!  
{ <+`%=r)4  
WsI`!ez;D  
!@xO]Jwv  
try{ Vy\Vpp  
URL url = new URL(sURL); >|$]=e,Z  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); l<6u@,%s  
httpConnection.setRequestProperty("User-Agent","NetFox"); @(3F4Z.i%.  
String sProperty = "bytes="+nStartPos+"-"; >f(?Mxh2  
httpConnection.setRequestProperty("RANGE",sProperty); `o[l%I\Q  
Utility.log(sProperty); Dac)`/  
{.p.?  
/jY u-H+C  
InputStream input = httpConnection.getInputStream(); Yj %]|E-  
//logResponseHead(httpConnection); a.Ho>(V/4  
^*K=wE}AG  
r|Ui1f5  
byte[] b = new byte[1024]; :xd;=;q5  
int nRead; . %RM8  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) b)LT[>f  
{ f7Gn$E|/r;  
nStartPos += fileAccessI.write(b,0,nRead); d1b] +AG4  
//if(nThreadID == 1) L, JQ\!c  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos);  is'V%q  
} YuXJT*  
T(b9b,ov)  
4&/CES  
Utility.log("Thread " + nThreadID + " is over!"); JU 9GJ"  
bDownOver = true; 22gh!F%)  
//nPos = fileAccessI.write (b,0,nRead); j[>cv;h ;  
} {/'T:n#  
catch(Exception e){e.printStackTrace ();} y0zMK4b  
} +P/kfY"  
} W(,j2pU  
3/G^V'Yu  
}>A q<1%  
//打印回应的头信息 ]<;,HGO  
public void logResponseHead(HttpURLConnection con) S c)^k  
{ _?{7%(C  
for(int i=1;;i++) JJ?{V:  
{ Ei;tfB  
String header=con.getHeaderFieldKey(i); Z_d"<k}I  
if(header!=null) "yWw3(V2>  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); PRKZg]?  
Utility.log(header+" : "+con.getHeaderField(header)); o/5-T4  
else ARk(\,h  
break; ']_2@<XW)  
} rQ;w{8J\t  
} 5/meH[R\M  
HA6tGZP*L  
i "8mrWb  
public void splitterStop() [>=!$>>;8  
{ rP@#_(22  
bStop = true; -dntV=  
} O9=/\Kc  
~+q1g[6  
2MkrVQQ9g  
} l$42MRi/  
|VfEp  
'h>uR|  
/* |V9[a a*c  
**FileAccess.java d*(aue=  
*//文件访问(定位,写) $TQhr#C]  
package NetFox; &!!*xv-z  
import java.io.*; 5>k:PKHL  
@u~S!(7.Wi  
&Y@i:O  
public class FileAccessI implements Serializable{ }X(&QZ7i`  
+mQ5\14#  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 \2SbW7"/;P  
RandomAccessFile oSavedFile; m'4f'tbN  
long nPos; rzjVUPdnh  
c_lHj#A(l  
)>volP  
public FileAccessI() throws IOException lj4Fg*/Yn  
{ Zt=|q$"  
this("",0); Q&9 yrx.  
} P7x;G5'.  
S-Uod y  
@"@a70WHk  
public FileAccessI(String sName,long nPos) throws IOException .3!Wr*o  
{ IqOg{#sm  
oSavedFile = new RandomAccessFile(sName,"rw"); .sMs_ 5D  
this.nPos = nPos; s**<=M GK  
oSavedFile.seek(nPos); 36d nS>4  
} j\>LJai"  
.l}Ap7@  
H4/wO  
public synchronized int write(byte[] b,int nStart,int nLen) _|k$[^ln^  
{ ZsmOn#`=^}  
int n = -1; 2RiJm"   
try{ 7Ai?}%b-  
oSavedFile.write(b,nStart,nLen); \kADh?phV  
n = nLen; sNf& "C!;  
}   f XD+  
catch(IOException e) KA3U W  
{ d} >Po%r:  
e.printStackTrace (); bIQ,=EA1  
} x4_IUIgh  
qJ ey&_  
}@DCcf$<  
return n; ) SV.|  
} j=\h|^gA  
WI8}_){ d  
9zaN fs  
} [Nyt0l "z  
$d?+\r:I{,  
6].[z+  
/* MP]<m7669*  
**SiteInfoBean.java =BJLj0=N  
*/ %sa?/pjK  
package NetFox; `Sod]bO +U  
4u{S?Ryy  
j,IRUx13f  
public class SiteInfoBean {  W!Tx%  
m/HT3<F  
N?GTfN  
private String sSiteURL; //Site's URL 1wSAwpz  
private String sFilePath; //Saved File's Path \Z{tC$|H  
private String sFileName; //Saved File's Name uvys>]+  
private int nSplitter; //Count of Splited Downloading File iP:i6U]  
|vI*S5kn6A  
QM$UxWo-  
public SiteInfoBean() ZOK!SBn^?  
{//nSplitter的缺省值为5 PyeNu3Il4  
//default value of nSplitter is 5 6opin  
this("","","",5); D9rQ%|}S  
} 6BE,L  
ep>!jMhJa  
kpOdyn(  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) _]:b@gXUw  
{ *k?:k78L  
sSiteURL= sURL; E)b$;'  
sFilePath = sPath; R2bqhSlF  
sFileName = sName; bM W|:rn  
this.nSplitter = nSpiltter; F.s$Y+c!6  
2.qPMqH  
}\ _.Mg^y  
} yOM/UdWq  
[8V;Q  
~ |G&cg  
public String getSSiteURL() _H]\  
{ 'nmGHorp  
return sSiteURL; 4.A^5J'W  
} q^X7x_  
w,|@e_|J  
unDW2#GX  
public void setSSiteURL(String value) 3:nhZN/95T  
{ 0KA*6]h t  
sSiteURL = value; SmXJQ@jN  
} 7?lz$.*Avp  
Bk8}K=%w  
<JPN< Kv  
public String getSFilePath() cXweg;  
{ ,05PYBc3  
return sFilePath; y<`5  
} 7lC$UQx8  
!z?   
MGdzrcF  
public void setSFilePath(String value) "M%R{pGA7  
{ D?Oe";"/  
sFilePath = value; ]4~Yi1]  
} +IZ=E >a  
VZ]iep  
"&(/bdah?&  
public String getSFileName() H4M=&"ll}  
{ Ae5A@4  
return sFileName; 4KPn V+h"b  
} O>`k@X@9/  
kUBE+a6#  
?<Qbp;WBo  
public void setSFileName(String value) q` S ~w  
{ Y:*% [\R  
sFileName = value; vG|!d+  
} z']6C9m}  
xj5TnE9^  
KGt:  
public int getNSplitter() KpN]9d   
{ X G#?fr}L  
return nSplitter; +'F;\E  
} y_PA9#v7  
#N{]  
A %w9Da?B  
public void setNSplitter(int nCount) !Uiq3s`1T  
{ _z p<en[  
nSplitter = nCount; =7!s8D,[  
} rfV'EjiM}  
} (Ypy}  
Y7G sL7I  
py6<QoGV  
/* a)|y0w)vV  
**Utility.java L : $ `8  
*/ a\sK{`|X*  
package NetFox; DJGafX^  
9.)z]Gav  
zC50 @S3|  
public class Utility { ?NE/ }?a  
kBP?_ O  
i)l0[FNI}  
public Utility() iXWzIb}CJ-  
{ Om.%K>V  
/gAT@Vx  
SIK:0>yK"  
} l|q-kRRjn  
AA\)BNM  
//线程睡眠 t 7Y*/v&P(  
public static void sleep(int nSecond) @9^OHRZX  
{ w4fKh  
try{ j"Jf|Hq $  
Thread.sleep(nSecond); |E~c#lV  
}  |q3X#s72  
catch(Exception e) [kg^S`gc#  
{ qV=:2m10x  
e.printStackTrace (); ):N#X<b':  
} Jp jHbG  
} L|1,/h 8p  
,#;hI{E  
//日志 MkW=sD_  
public static void log(String sMsg) V7,dx@J-  
{ cvcZ\y  
System.err.println(sMsg); &mX_\w /%  
} 8K4^05*S   
*+v*VH  
I<}% L V  
public static void log(int sMsg) /? %V% n  
{ I`{3I-E  
System.err.println(sMsg); xLed];2G  
} yPE3Awh5  
} U\%r33L )  
RUY7Y?  
O=__w *<  
/* ")KqPD6k  
**TestMethod.java ,X!)zAmm  
*/ aiPm.h>  
package NetFox; B}[CU='P*  
=!-}q  
L9jT :2F  
public class TestMethod { ]9_gbQ   
eipg,EI  
+-tFgXG  
public TestMethod() pW+uVv,  
{ ///xx/weblogic60b2_win.exe ]x)!Kd2>  
try{ rC@VMe|0  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); pZ8J\4+  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -sJ1q^;f@  
SiteFileFetch fileFetch = new SiteFileFetch(bean); !aSj1 2J  
fileFetch.start(); Oj-\  
} 9(t(sP_  
catch(Exception e){e.printStackTrace ();} ;6@sC[  
HGAi2+&  
s(py7{ ^K  
} 'goKYl#1Q  
*=i&n>  
<ll?rPio"  
public static void main(String[] args) Muwlehuq  
{ Cu`  
new TestMethod(); ![Qi+xyc  
} xHt7/8wF  
} 4Q!A w  
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