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http断点续传简单实现(java)

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/* T#MA#H2  
**SiteFileFetch.java \O8Y3|<  
*/ m1~qaD<DZ$  
package NetFox; fW_}!`:  
import java.io.*; 2LhfXBWf  
import java.net.*; pDLu+ }@  
&:!ZT=  
gaLEhf^  
public class SiteFileFetch extends Thread { V6DBKq  
XgwMppacw  
[u`17hyX  
SiteInfoBean siteInfoBean = null; //文件信息Bean o 2[vM$]  
long[] nStartPos; //开始位置 .g6PrhzFbk  
long[] nEndPos; //结束位置 Pg!;o= { M  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 1qB!RIau  
long nFileLength; //文件长度 h,!G7V  
boolean bFirst = true; //是否第一次取文件 h|(Z XCH  
boolean bStop = false; //停止标志 e>])m3xvn  
File tmpFile; //文件下载的临时信息 rW=k%# p  
DataOutputStream output; //输出到文件的输出流 PK:o}IWn~x  
1q}u?7nnSG  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) =j'J !M  
public SiteFileFetch(SiteInfoBean bean) throws IOException r`&2-]  
{ vF*^xhh  
siteInfoBean = bean; 0?J|C6XM#4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ? 6yF{!F*  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0)6i~MglY  
if(tmpFile.exists ()) ;~'cITL  
{ 7G<KrKal  
bFirst = false; AF9[2AH=Y  
read_nPos(); Mp^OL7p^^  
} VuX >  
else pJ 2:` f<;  
{ imJ[:E  
nStartPos = new long[bean.getNSplitter()]; 7d M6;`V^  
nEndPos = new long[bean.getNSplitter()]; &;~2sEo,  
} #Lhj0M;a  
LK   
? $)x$nS`  
Tc'{i#%9j  
} T!^?d5uW#  
RpmBP[  
tdw\Di#m  
public void run() E1U4v&P  
{ A}t&-  
//获得文件长度 -H ac^4uF  
//分割文件 U- *8%>Qp  
//实例FileSplitterFetch =ELDJt  
//启动FileSplitterFetch线程 *MnG-\{j  
//等待子线程返回 D^N#E>,  
try{ BST7y4R)BS  
if(bFirst) !yV,|)y5F  
{ (^s&M  
nFileLength = getFileSize(); m p|20`go  
if(nFileLength == -1) epG X.  
{ *D09P%  
System.err.println("File Length is not known!"); HX /GLnY/X  
} |&0"N[t  
else if(nFileLength == -2) .%J?T5D  
{ St~SiTJU  
System.err.println("File is not access!"); T~wZ  
} (A]m=  
else k+7M|t.?4  
{ ;mo\ yW1  
for(int i=0;i<nStartPos.length;i++) Wd^F%)(  
{ YjX!q]56  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ; $ ?jR c  
} V. bH$@ej  
for(int i=0;i<nEndPos.length-1;i++) !UgUXN*  
{ gvTOC F  
nEndPos = nStartPos[i+1]; iX>!ju'V  
} D_ Bx>G9  
nEndPos[nEndPos.length-1] = nFileLength; O%fp;Y{`  
} }Pm(oR'KTJ  
} $_URXI  
NrI 5uC7  
ulPrb>i  
//启动子线程 N?2 #YTjR  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; evg 7d  
for(int i=0;i<nStartPos.length;i++) eF8 aB?&"  
{ z|DA _dG  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), f9 l<$l  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), o {Xw Li  
nStartPos,nEndPos,i); |peMr#  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); VhH]n yi7D  
fileSplitterFetch.start(); aaf_3UH.B  
} $cJN9|$6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ;Xd\$)n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); yf#%)-7(  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", M::IE|h  
nEndPos = " + nFileLength); bE`*Uw4  
// fileSplitterFetch[nPos.length-1].start(); XoxR5arj  
e`Zg7CaDd  
f5=t*9_-[  
//等待子线程结束 ?D~SHcBaN  
//int count = 0; io+7{B=u$  
//是否结束while循环 )QSt7g|OF  
boolean breakWhile = false; ( /x@W`  
Gs=a(0 0i?  
OJ_2z|f<  
while(!bStop) Z1V'NJI+  
{ NW4 s'roP  
write_nPos(); 2YE]?!   
Utility.sleep(500); WKrZTPD'm  
breakWhile = true; X%9xuc  
wD?=u\% &  
|jaY[_ .@  
for(int i=0;i<nStartPos.length;i++) n;k97>m${x  
{ 9+is?Pj  
if(!fileSplitterFetch.bDownOver) [P&,}o)+E0  
{ ~4~Tcn  
breakWhile = false; \'LCC-  
break; 4 _U,-%/  
} t zW<&^  
} iQ]c k-  
if(breakWhile) v20I<!5w  
break; M%5$-;6~_  
g7U:A0Z  
!NAX6m  
//count++; 7f\^VG  
//if(count>4) MMA@J  
// siteStop(); J2 rLsNC]0  
} =<'iLQb1  
0rm;)[SjF  
b gc<)=  
System.err.println("文件下载结束!"); ;~@PYIp  
} rIFC#Jd/  
catch(Exception e){e.printStackTrace ();} }AsF\W+5  
} :D+ SY  
iUG/   
nog\,NT  
//获得文件长度 i{FC1tVeL_  
public long getFileSize() 9hs{uxwuEE  
{ Obc3^pV&  
int nFileLength = -1; Ae_ E;[mj  
try{ ;gW|qb+#)j  
URL url = new URL(siteInfoBean.getSSiteURL()); FTYLMQ i  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4 TQISu)  
httpConnection.setRequestProperty("User-Agent","NetFox"); +81+4{*  
g/X=#!  
33KPo0g7  
int responseCode=httpConnection.getResponseCode(); 6 % y)  
if(responseCode>=400) vS t=Ax3]  
{ np\Q&  
processErrorCode(responseCode); tEX~72v  
return -2; //-2 represent access is error j_WF38o  
} qM:)daS1w  
/qq&'}TZP  
j5Wx*~@(  
String sHeader; YlcF-a  
v3JIUdU=P  
^57fHlw  
for(int i=1;;i++) cKYvRe  
{ L{0OMyUA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); S5 nw  
//Utility.log(in.readLine()); IM5^E#-g7  
sHeader=httpConnection.getHeaderFieldKey(i); a=B0ytNm  
if(sHeader!=null) 5NF&LM;i(  
{ qCkg\)Ks5I  
if(sHeader.equals("Content-Length")) DF[b?  
{ H6JMN1#t$  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); Jx9%8Ek  
break; vzm4  
} E|4XQ|B@  
} >T*g'954xF  
else n`KXJ?t  
break; |AfQ_iT6c  
} \\G6c4 fC  
} ,M h/3DPgE  
catch(IOException e){e.printStackTrace ();} O/^w! :z'  
catch(Exception e){e.printStackTrace ();} dDn4nwH  
PRlo"kN  
8v=47G  
Utility.log(nFileLength); IC-xCzR  
y{?jr$js<  
wG?kcfu  
return nFileLength; geN%rD  
} jp]geV54  
3cFLU^  
%+! 9  
//保存下载信息(文件指针位置) e&4wwP"`<  
private void write_nPos() IIn\{*|mW  
{ x15tQb+  
try{ r~2@#gTbl  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ZznWs+  
output.writeInt(nStartPos.length); 7%}3Ghc%  
for(int i=0;i<nStartPos.length;i++) Ng39D#_)  
{ f EiEfu  
// output.writeLong(nPos); +;iesULXn  
output.writeLong(fileSplitterFetch.nStartPos); :(p rx   
output.writeLong(fileSplitterFetch.nEndPos); <({eOh5 N  
} {]Iu">*  
output.close(); %1 ^jd\  
} m.a1  
catch(IOException e){e.printStackTrace ();} 5a_!&  
catch(Exception e){e.printStackTrace ();} l<: E+lU  
} JI,hy <3l0  
.*f4e3  
kpw4Mq@  
//读取保存的下载信息(文件指针位置) W!B4< 'Fjc  
private void read_nPos() wP':B AQ4U  
{ 2^ZPO4|  
try{ "#k(V=y  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E=*Q\3G~  
int nCount = input.readInt(); wEc5{ b5M  
nStartPos = new long[nCount]; 7CMgvH)O  
nEndPos = new long[nCount]; cH-Zj  
for(int i=0;i<nStartPos.length;i++) n4&j<zAV{  
{ ?N*@o.  
nStartPos = input.readLong(); p2vUt  
nEndPos = input.readLong(); sx^? Iw,N'  
} ;H r@0f  
input.close(); OjEA;;qq  
} w&cyGd D5  
catch(IOException e){e.printStackTrace ();} uBkn y;  
catch(Exception e){e.printStackTrace ();} 7 =*k@9  
} K$GXXE`  
J+gsmP-_  
3&Rqz9W  
private void processErrorCode(int nErrorCode) RX\O'Zwlj  
{ @N{Ht)1r  
System.err.println("Error Code : " + nErrorCode); |+~2sbM  
} 3i}B\ {  
|3@Pt>Ikl  
kj=2+)!E7  
//停止文件下载 :|Nbk58  
public void siteStop() TC#B^m`'p  
{ 2U+p@}cQUA  
bStop = true; r3vj o(  
for(int i=0;i<nStartPos.length;i++) =xet+;~ji  
fileSplitterFetch.splitterStop(); Zs|sPatV<  
\)uad5`N  
BD#;3?|  
} d$~b`  
} OBSJbDqT  
//负责部分文件的抓取 :uDB3jN[  
**FileSplitterFetch.java N,Bs% p#1  
*/ s9bP6N!,  
package NetFox; )II,HT-LY  
cS7!,XC  
R_&z2I  
import java.io.*; "a{f? .X.  
import java.net.*; becQ5w/~  
:P"Gym  
rO%+)M$A  
public class FileSplitterFetch extends Thread { 2U{RA' s  
FRk_xxe"K  
K+OU~SED%F  
String sURL; //File URL k ,(:[3J  
long nStartPos; //File Snippet Start Position i~L7h=__  
long nEndPos; //File Snippet End Position ]m>MB )9  
int nThreadID; //Thread's ID 2wsZ&y%  
boolean bDownOver = false; //Downing is over (UXB#I~  
boolean bStop = false; //Stop identical (Fd4Gw<sq  
FileAccessI fileAccessI = null; //File Access interface io3'h:+9s  
K(<P" g(  
#7ZBbq3=  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException w!7/;VJ3d  
{ dS=,. }  
this.sURL = sURL; L-$g& -  
this.nStartPos = nStart; LXV6Ew5E  
this.nEndPos = nEnd; Qf]!K6eR  
nThreadID = id; FQ)Ekss~C  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 m/nn}+*C  
} $?{zV$r1  
CI'5JOqP  
1dsxqN(:  
public void run() ^ s4|  
{ Ft !~w#&-  
while(nStartPos < nEndPos && !bStop) 59 Y=VS  
{ 4]KceE  
H4Ek,m|c  
>E=a~ O  
try{ O8o18m8UH  
URL url = new URL(sURL); 9V\`{(R  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); P'~3WL4MKs  
httpConnection.setRequestProperty("User-Agent","NetFox"); nHjwT5Q+Q  
String sProperty = "bytes="+nStartPos+"-"; gMn)<u>  
httpConnection.setRequestProperty("RANGE",sProperty); jQ}| ]pj+  
Utility.log(sProperty); sTyGi1  
mIodD)?{  
~vF o 0k(  
InputStream input = httpConnection.getInputStream(); tH(#nx8  
//logResponseHead(httpConnection); ,-kZ5&r  
/WVMT]T6^,  
t%@ pyK  
byte[] b = new byte[1024]; rzLl M  
int nRead; miSC'!  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) B=`!  
{ Yg.u8{H  
nStartPos += fileAccessI.write(b,0,nRead); +8I0.,'  
//if(nThreadID == 1) }3lF;k(2g  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 69yyVu_  
} I5?LD=tt  
9~I WGj?  
]:fHvx_?`7  
Utility.log("Thread " + nThreadID + " is over!"); JN)t'm[kyE  
bDownOver = true; W:J00rsv=`  
//nPos = fileAccessI.write (b,0,nRead); d*HAKXd&:j  
} JH#+E04#  
catch(Exception e){e.printStackTrace ();} N>Y3[G+  
} bxq`E!]  
} cgOoQP/#  
K? k`U,  
FG\?_G  
//打印回应的头信息 %xz02$k  
public void logResponseHead(HttpURLConnection con) ;7>--_?=  
{ lUd,-  
for(int i=1;;i++) \-yi#N  
{ 6I0MJpLW  
String header=con.getHeaderFieldKey(i); g*M3;G  
if(header!=null) O~VUViS6$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); %BKTN@;7  
Utility.log(header+" : "+con.getHeaderField(header)); >w2u  
else -bF+uCfba  
break; * =l9gv&  
} + aF jtb  
} !ZW0yCwLQ  
nE84W$\  
9qA_5x%"%u  
public void splitterStop() Fu$sfq  
{ PV2904  
bStop = true; *TkABUL  
} NQ!F`  
u 36;;z  
C7PiuL?  
} A )cb  
HZ3<}`P_W  
i1C'  
/* <0m;|Ai'W  
**FileAccess.java R?Qou!*]  
*//文件访问(定位,写) ):@B1 yR  
package NetFox; { L5m`-x  
import java.io.*; v5o%y:~  
{Xj%JE[V  
8J0tya"z  
public class FileAccessI implements Serializable{ I j /J  
=g:\R$lQ  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 jg(A_V  
RandomAccessFile oSavedFile; ->(B: Cz  
long nPos; zqkmsFH{  
1Rh&04O>VL  
t JP(eaqZ  
public FileAccessI() throws IOException y (A"g3^=  
{ j3>< J  
this("",0); LmE-&  
} A5b}G  
8TZe=sD~cr  
g d-fJ._1  
public FileAccessI(String sName,long nPos) throws IOException mN`a]L'  
{ ~cjvo?)&e;  
oSavedFile = new RandomAccessFile(sName,"rw"); DI\sq8J^  
this.nPos = nPos; Fwr,e;Z  
oSavedFile.seek(nPos); P$bo8*  
} EbQ}w"{  
*bx cq  
*QX$Mo^E  
public synchronized int write(byte[] b,int nStart,int nLen) 8 _J:Yg  
{ XN@5TZoaW  
int n = -1; YAo g;QL  
try{ I}X8-WFB  
oSavedFile.write(b,nStart,nLen); u(R`}C?P'  
n = nLen; *))|ZE6jI  
} M<nn+vy`  
catch(IOException e) h| Ih4  
{ Sa0\9 3oa  
e.printStackTrace (); 0Ju{6x(|  
} @WmB0cc_  
jv ";?*I6.  
`xSXGI  
return n; "'Q:%_;  
} ]x|sT Kv2  
jcj)9;n=!  
/%)J+K)  
} ~VKw%WK  
`PL!>oa(8  
QS_u<B  
/* o,-@vp  
**SiteInfoBean.java " O4Z).5q3  
*/ JF7T1T  
package NetFox; -[=`bHo  
X:A\{^ ~  
D+V^nCcx%  
public class SiteInfoBean { 8Y9mB #X  
7"NUof?i  
7j Q`i;L}Y  
private String sSiteURL; //Site's URL E=y#~W  
private String sFilePath; //Saved File's Path G9 !1Wzs  
private String sFileName; //Saved File's Name }7V/(K  
private int nSplitter; //Count of Splited Downloading File ]O[f#lG  
sYz:(hZS  
xASj w?  
public SiteInfoBean() xiI!_0'  
{//nSplitter的缺省值为5 (.c?)_G,  
//default value of nSplitter is 5 Umqm5*P(  
this("","","",5); #ua#$&p  
} ?@nu]~  
*VH1(E`hl  
0ode&dB  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) C8?/$1|RL  
{ +#W5Qb}VR  
sSiteURL= sURL; mUjA9[@   
sFilePath = sPath; -+L1Hid.7  
sFileName = sName; <AVpFy  
this.nSplitter = nSpiltter; W`Soa&9  
ZA!vxQ?P,  
&~j"3G;e  
} yoH6g?!O  
+RbCa c  
aU3&=aN+  
public String getSSiteURL() M1^pW 63  
{ qAm%h\  
return sSiteURL; 0zd1:*KR,  
} i@2?5U>h  
|y]#-T?)t  
*}?^)z7w  
public void setSSiteURL(String value) MV/JZ;55  
{ .JzO f[g5  
sSiteURL = value; u@o3p*bQ  
} fROhn}<**[  
|$D^LY  
1}(g=S  
public String getSFilePath() HJ2]xe09  
{ Z#F2<*+Pe  
return sFilePath; FOZqN K  
} ^}WeBU  
QKVZ![Y!s  
M4QMD;Ez  
public void setSFilePath(String value) C}Khh`8@5.  
{ &t4j px  
sFilePath = value; htaB! Q?V  
} k,r\^1h  
MW p^.  
M?_VYK  
public String getSFileName() 03MB,  
{ 4'{j'kuv  
return sFileName; $tb$gO  
} t0wLj}"U  
fD!O aK  
MP T[f  
public void setSFileName(String value) X1+Wb9P  
{ -i58FJ`B  
sFileName = value; _-EHG  
} pdE=9l'  
kJ~^  }o  
MOj 0"x)  
public int getNSplitter() Gm*i='f!?  
{ hX;xbl  
return nSplitter; KB-7]H  
} VQX#P<  
[E=t{&t  
#Z fg  
public void setNSplitter(int nCount) QutQG  
{ PPohpdd)  
nSplitter = nCount; n&@\[,B  
} Qd@`jwjS  
} L%<1cE))  
(ttO O45  
7)[4|I  
/* iX4/;2B=,  
**Utility.java 9m<>G3Jr  
*/ -0>@jfP^D  
package NetFox; hG3b7!^#g  
*iYs,4  
&359tG0@P  
public class Utility { [u~#F,_ow  
6N]v9uXZ  
^oA^z1>3  
public Utility() pO"V9[p]  
{ wKwireOs  
'*22j ]  
C7PHZ`<  
} Ua( !:5q?  
}4+S_b  
//线程睡眠 1MOQ/N2BR  
public static void sleep(int nSecond) C,K P!B{  
{ Zr`:A$  
try{ u+S*D\p<`  
Thread.sleep(nSecond); W[+E5I  
} oZ!rK/qoA  
catch(Exception e) 4j/8Otn  
{ \p.ku%{  
e.printStackTrace (); $NqT ={!  
} MvObx'+  
} V" I+E  
QarA.Ne~  
//日志 Al 0zL  
public static void log(String sMsg) 3pm;?6i6  
{ " >;},$  
System.err.println(sMsg); #Jg )HU9  
} A`IE8@&Z'  
!30BZM^  
K47W7zR  
public static void log(int sMsg) (]rtBeT  
{ %<K`d  
System.err.println(sMsg); c^I_~OwaE  
} 7j{SCE;  
} Ao 1*a%-.  
DaaLRMQ=  
/)6<`S(  
/* 3%'$AM}+s  
**TestMethod.java 6f0 WN  
*/ NO"=\Zn6  
package NetFox; %KRAcCa7  
O']-<E`1k  
p ^T0(\1  
public class TestMethod { $--W,ov5j  
4R@3jGXb8q  
`2 Vc*R  
public TestMethod() %J7 ;b<}To  
{ ///xx/weblogic60b2_win.exe H7*/  
try{ a+IU<O-J?  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); #O qfyY!  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); G[)QGZ}8b  
SiteFileFetch fileFetch = new SiteFileFetch(bean); HLa|yc B%  
fileFetch.start(); ,M5J~Ga  
} T+RfMEdr  
catch(Exception e){e.printStackTrace ();} KZJ;O7'`  
Kp8!^os  
;E(%s=i  
} <Sb W QbN  
$D\SueZ  
vfm |?\  
public static void main(String[] args) pzHN:9r  
{ U!TFFkX[  
new TestMethod(); ]xb R:CYJ  
} 4Rp2  
} h@t&n@8O?  
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