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http断点续传简单实现(java)

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/* Rqwzh@}  
**SiteFileFetch.java UobyK3.%  
*/ H|cNH=  
package NetFox; 85 EQ5yY  
import java.io.*; #%J5\+ua  
import java.net.*; OD' ]:  
$$:ZX  
y_xnai  
public class SiteFileFetch extends Thread { l5l>d62  
)54%HM_$k  
qV5DW0.  
SiteInfoBean siteInfoBean = null; //文件信息Bean G=;k=oX(  
long[] nStartPos; //开始位置 `eu9dLz H  
long[] nEndPos; //结束位置 .NtbL./=|  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 ,=?{("+  
long nFileLength; //文件长度 s2j['g5  
boolean bFirst = true; //是否第一次取文件 ngj,x7t  
boolean bStop = false; //停止标志 )%!XSsY.N|  
File tmpFile; //文件下载的临时信息 OL_{_K(w  
DataOutputStream output; //输出到文件的输出流 8M@BG8  
iC iZJ"  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) RwS@I /  
public SiteFileFetch(SiteInfoBean bean) throws IOException Y>jiXl?&  
{ "c}@V*cO<d  
siteInfoBean = bean; 5*[2yKsTi  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 7ugZE93!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); O;7)Hjwt  
if(tmpFile.exists ()) &uC@|dbC5  
{ [AV4m   
bFirst = false; Ltjbxw"Qd  
read_nPos(); `jS T  
} ?\8?%Qk  
else D&HV6#  
{ i#%aTRKHd6  
nStartPos = new long[bean.getNSplitter()]; s1?[7yC  
nEndPos = new long[bean.getNSplitter()]; p4p@^@<>X  
} ~b {Gz6u>  
mS k5u7  
lO2[JP  
E^U0f/5 m  
} xkOpa,=FI  
y4+ ;z2' >  
S*AERm   
public void run() Lg"C]  
{ u&wiGwF[  
//获得文件长度 j5@:a  
//分割文件 K'#E3={tt  
//实例FileSplitterFetch W2uOR{ '?  
//启动FileSplitterFetch线程 p&VU0[LIC0  
//等待子线程返回 :!zl^J;  
try{ &@ JvnO:  
if(bFirst) DWdW,xG  
{ +l=r#JF  
nFileLength = getFileSize(); !x'/9^i~v  
if(nFileLength == -1) Z,iHy3`  
{ XD"_Iq!  
System.err.println("File Length is not known!"); G%d (  
} ')GSAY7  
else if(nFileLength == -2) .f+TZDUO  
{ u^029sH6j  
System.err.println("File is not access!"); BB|?1"neg  
} # p[',$cC  
else wgd/(8d  
{ uYrfm:4S  
for(int i=0;i<nStartPos.length;i++) !'LW_@  
{ {nU=%w"\  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); {}:ToIp  
} OzC\9YeA  
for(int i=0;i<nEndPos.length-1;i++) \=>H6x]q  
{ 3]?#he  
nEndPos = nStartPos[i+1]; %Qk/_ R1   
} <V>dM4Mkr  
nEndPos[nEndPos.length-1] = nFileLength; UwC=1g U  
} _#vrb;.+  
} Xy%p"b<  
imiR/V>N  
G\T fL^A  
//启动子线程 ^] kF{ o?  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; O#Wh TDF"  
for(int i=0;i<nStartPos.length;i++) i*CZV|t US  
{ ?.Pg\ur  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ]r_;dYa  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), vOg#Dqn-  
nStartPos,nEndPos,i); ,]T2$?|  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); <id}<H  
fileSplitterFetch.start(); ^eoLAL  
} s=[h?kB  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ,!U=|c"k)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); &IlU|4`R%  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", `Qeg   
nEndPos = " + nFileLength); VE8;sGaJ  
// fileSplitterFetch[nPos.length-1].start(); 0@AAulRl  
*-xU2  
;j2vHU#q-  
//等待子线程结束 Qyy.IPTP  
//int count = 0; kY'T{Sm1^  
//是否结束while循环 Li Kxq=K  
boolean breakWhile = false; `mN4_\]  
\rPbK+G.  
t'ZWc\  
while(!bStop) <I"S#M7-s  
{ b:w?PC~O  
write_nPos(); Ag@;  
Utility.sleep(500); u_rdmyq$x/  
breakWhile = true; |2KAo!PI  
cp o-.  
U)3DQ6T99  
for(int i=0;i<nStartPos.length;i++) fNrgdfo  
{ NssELMtF!g  
if(!fileSplitterFetch.bDownOver) ;D$)P7k6  
{ _2N$LLbg  
breakWhile = false; D1 &A,2wO  
break; <\;#jF%V  
} o;?/HE%,[  
} 85GKymz$P  
if(breakWhile) MQ"xOcD*F  
break; r7',3V  
p ]d] QMu  
~9j%Hm0ht  
//count++; ?@V[#.  
//if(count>4) FHV-BuH5  
// siteStop(); ^+g$iM[`f  
} jRL<JZ1N  
H#ncM~y*  
L5,NP5RC  
System.err.println("文件下载结束!"); u7=U^}#  
} /d%=E  
catch(Exception e){e.printStackTrace ();} B7!3-1<k>  
} !o$!Frc  
aE2.L;Tk?  
t]-5 ]oI  
//获得文件长度 [p<w._b i  
public long getFileSize() ^yOZArc'r  
{ F;]%V%F.X  
int nFileLength = -1; -a-(r'Qc(  
try{ [Jv@J\  
URL url = new URL(siteInfoBean.getSSiteURL()); #t+d iR  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); f%*/cpA)  
httpConnection.setRequestProperty("User-Agent","NetFox"); 8]LD]h)B"  
Z4\=*ic@  
l'eyq}&  
int responseCode=httpConnection.getResponseCode(); 6R^^.tCs  
if(responseCode>=400) 8-O)Xx}cU  
{ LGtIm7  
processErrorCode(responseCode); V5rS T +  
return -2; //-2 represent access is error KY~- ;0x  
} BT(CM,bp  
rOVVL%@QqJ  
w`5xrqt@  
String sHeader; Ih"XV  
cCxBzkH6  
p3 ^ m9J  
for(int i=1;;i++) ,S!azN=  
{ }+sT4'Ah>  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Er{>p|n =  
//Utility.log(in.readLine()); yNTK .  
sHeader=httpConnection.getHeaderFieldKey(i); ej"+:. "\e  
if(sHeader!=null) 0vw4?>Jf@  
{ VTH> o>g  
if(sHeader.equals("Content-Length")) >qF CB\(  
{ =y-@AU8  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); $b mLu=9  
break; a0#J9O_  
} (I./ Uu%  
} 1 .6:#  
else .;N1N^  
break; ( U xW;  
} V=*wKuB  
} <Sr  
catch(IOException e){e.printStackTrace ();} [)TRTxFb  
catch(Exception e){e.printStackTrace ();} r! MWbFw|X  
N}t 2Nu-  
Ll4g[8  
Utility.log(nFileLength); 5bg s*.s  
sL$:"=  
)<tI!I][j  
return nFileLength; 9c("x%nLpB  
} l~$+,U&XNe  
IqoR7ajA  
5wDg'X]>V  
//保存下载信息(文件指针位置) sc,vj'r  
private void write_nPos() )'+8}T]xQ  
{ WA&!;Zq  
try{ #NryLE!/  
output = new DataOutputStream(new FileOutputStream(tmpFile)); bXNk%W[n  
output.writeInt(nStartPos.length); =aTv! 8</  
for(int i=0;i<nStartPos.length;i++) 1waTTT?"Ho  
{ L}pt)w*V1j  
// output.writeLong(nPos); W@I|Q -  
output.writeLong(fileSplitterFetch.nStartPos); N <Xq]! K-  
output.writeLong(fileSplitterFetch.nEndPos); z.;ez}6%V  
} 71t* %  
output.close(); q}?4f *WC  
} ys kO  
catch(IOException e){e.printStackTrace ();} Z '7  
catch(Exception e){e.printStackTrace ();} P`cq H(   
} WL"^>[Vq  
TtTj28 k7  
j=r P:#  
//读取保存的下载信息(文件指针位置) @pRlxkvV  
private void read_nPos() ][p>Y>:b-  
{ ~XmLX)vO/  
try{ G VYkJ0,  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Yz +ZY  
int nCount = input.readInt(); rr02pM0  
nStartPos = new long[nCount]; M,\:<kNI  
nEndPos = new long[nCount]; x5-}h*  
for(int i=0;i<nStartPos.length;i++) S;286[oq@  
{ Rx=>6,)'  
nStartPos = input.readLong(); lUMS;H(  
nEndPos = input.readLong(); fUA uqfj[  
} 1`qMj0Y_  
input.close(); [rV>57`YD  
} 4p,EBn9(  
catch(IOException e){e.printStackTrace ();} '|8} z4/g  
catch(Exception e){e.printStackTrace ();} GE%Z9#E  
} P 'od`  
hFy;ffs.  
DrY:9[LP  
private void processErrorCode(int nErrorCode) ]Hefm?9*^  
{ j~jV'f.:H  
System.err.println("Error Code : " + nErrorCode); =*c7i]@}  
} /n{omx  
A#J`;5!Sc  
lHPd"3HDK  
//停止文件下载 f\sQO&  
public void siteStop() ]\hSI){  
{ NRIG1v>  
bStop = true; UMm!B`M  
for(int i=0;i<nStartPos.length;i++) biU^[g("  
fileSplitterFetch.splitterStop(); -7@/[9Gf`:  
zGkS^Z=(  
|8l<$J  
} @v)p<r^M">  
} @] DVD  
//负责部分文件的抓取 }o?APvd  
**FileSplitterFetch.java S79;^X  
*/ eoG$.M"  
package NetFox; |Sy<@oq  
)I^7)x  
SBfT20z[  
import java.io.*; yDegcAn?  
import java.net.*; Kzm+GW3o[  
AicBSqUke  
3yU.& k  
public class FileSplitterFetch extends Thread { (mTE;s(  
~O oidKT  
5A3xVN=  
String sURL; //File URL 26I_YL,S  
long nStartPos; //File Snippet Start Position W_\5nF  
long nEndPos; //File Snippet End Position c|B.n]Z  
int nThreadID; //Thread's ID !h23cj+V  
boolean bDownOver = false; //Downing is over IYS)7`{]  
boolean bStop = false; //Stop identical SwTL|+u  
FileAccessI fileAccessI = null; //File Access interface }J:U=HJ  
,*&:2o_r  
_u5#v0Y  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $0>60<J  
{ %7IugHH9y  
this.sURL = sURL; p93r'&Q  
this.nStartPos = nStart; t\k$};qJ  
this.nEndPos = nEnd; @hiCI.?X  
nThreadID = id; /'l{E  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Cz\e w B  
} _/-jX  
4U+xb>  
7vrl'^1  
public void run() |Mu p8(gCk  
{ =S+wCN  
while(nStartPos < nEndPos && !bStop) ;o2$ Q  
{ m.# VYN`+A  
bYpnt V  
t^R][Ay&  
try{ bnq; )>&  
URL url = new URL(sURL); ' g=  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cdl&9-}  
httpConnection.setRequestProperty("User-Agent","NetFox"); .oYl-.E>&  
String sProperty = "bytes="+nStartPos+"-"; :8=ikwQ  
httpConnection.setRequestProperty("RANGE",sProperty); &_dt>.  
Utility.log(sProperty); {JZZZY!n2  
Tc>   
.w=/+TA  
InputStream input = httpConnection.getInputStream(); r ~jm`y  
//logResponseHead(httpConnection); \E72L5nJW  
PV'x+bN5  
4sF"6+%5d  
byte[] b = new byte[1024]; m? J0i>H  
int nRead; 1 d}Z(My  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) u~7hWiY<2  
{ H]{v;;'~  
nStartPos += fileAccessI.write(b,0,nRead); C*)3e*T*  
//if(nThreadID == 1) GP!?^r:en  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ^84G%)`&  
} rb5~XnJk  
\o}xF@sM5  
, pDnRRJ!  
Utility.log("Thread " + nThreadID + " is over!"); %p^wZtm  
bDownOver = true; 8=B|C'>  
//nPos = fileAccessI.write (b,0,nRead); M -cTRd-i  
} ww\CQ6/h  
catch(Exception e){e.printStackTrace ();} l&OKBUG  
} [842&5Pd?  
} DBW[{D E  
WejY y|  
`<`` 8  
//打印回应的头信息 :|V$\!o'U  
public void logResponseHead(HttpURLConnection con) \HxT@UQ)~  
{ q0i(i.h  
for(int i=1;;i++) 8Wrh]egu1  
{ !;&p"E|b#  
String header=con.getHeaderFieldKey(i); R]}}$R`j  
if(header!=null) ]i&6c  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); dt \TQJc~  
Utility.log(header+" : "+con.getHeaderField(header)); ck ]Do!h  
else BgurzS4-  
break; d A@]!  
}  8n#HFJ~  
} PWaw]*dFmy  
A-H&  
FcR=v0),  
public void splitterStop() T6O::o6  
{ |%F=po>w  
bStop = true; ~P*6ozSYpY  
} 3m]4=  
\8)U!9,$nn  
lP[w?O  
} Y}t \4 di  
1tEgl\u\  
wKtl+}}  
/* kw >v:F<M  
**FileAccess.java /[a~3^Gs^  
*//文件访问(定位,写) q.KG^=10  
package NetFox; 6Z>FTz_  
import java.io.*; A>vBQN  
UldXYtGe  
5L+>ewl  
public class FileAccessI implements Serializable{ wxR,OR  
5gb|w\N>  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 v~f HYa>  
RandomAccessFile oSavedFile; A;;fACF8e  
long nPos; ciFmaM.  
_Zp}?b5Q  
nF54tR[  
public FileAccessI() throws IOException |'.*K]Yp  
{ 1Ce@*XBU  
this("",0); yQ_B)b  
} H7z,j}l  
)JDs\fUE  
9A/\h3HrJ  
public FileAccessI(String sName,long nPos) throws IOException Hbj,[$Jb  
{ #X%~B'  
oSavedFile = new RandomAccessFile(sName,"rw"); }6p@lla,%]  
this.nPos = nPos; PXK7b2fE.  
oSavedFile.seek(nPos); \l'm[jy>  
} Lz`E;k^  
\s/s7y6b+  
oiF}?:7Q7  
public synchronized int write(byte[] b,int nStart,int nLen) ^ssK   
{ MuYk};f  
int n = -1; ;+e}aER&9  
try{ O!m vJD  
oSavedFile.write(b,nStart,nLen); 5QW=&zI`=  
n = nLen; `_BNy=`s*  
} fL_4uC i\  
catch(IOException e) wg7V-+@i  
{ w,.+IV$Kk  
e.printStackTrace (); V@B__`y7  
} -|J"s$yO4  
HKU~UTRnZ  
nim*/LC[:  
return n; 3p3 9`"~  
} ~k\fhx  
h hG4-HD  
J4QXz[dG  
} 931bA&SL=/  
aH 4c02s$  
E[2m&3&  
/* N^#ZJoR  
**SiteInfoBean.java M}`B{]lLz  
*/ 9 8j>1 "8  
package NetFox; =+/eLKG  
&Lt}=3G  
t#Z-mv:(  
public class SiteInfoBean { E.r>7`E  
/,89p&h  
1%EBd%`#  
private String sSiteURL; //Site's URL xe#FUS 3  
private String sFilePath; //Saved File's Path yyoqX"v[  
private String sFileName; //Saved File's Name nc~F_i=  
private int nSplitter; //Count of Splited Downloading File s:OFVlC%\  
1/RsptN"v  
5A%w 8Qv  
public SiteInfoBean() b1^vd@(lx  
{//nSplitter的缺省值为5 Ozw;(fDaU  
//default value of nSplitter is 5 t`WB;o!  
this("","","",5); NhfJ30~  
} rx $mk  
r#+d&.|  
zAK+8{,  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fdxLAC  
{ 1QqYQafA  
sSiteURL= sURL; 8B7cBkl:  
sFilePath = sPath; +vYoB$!  
sFileName = sName; e&simX;W  
this.nSplitter = nSpiltter; *v;!-F&8>  
c]$i\i#  
qHsUP;7  
} k >F'ypm  
bBu,#Mc  
@PN#p"KaT  
public String getSSiteURL() -u&6X,Oq\u  
{ 9:fOYT$8  
return sSiteURL; B.wYHNNV  
} *meZ8DV2DH  
c;%_EN%  
wmk *h-  
public void setSSiteURL(String value) >NqYyW,%  
{ Ot:CPm@  
sSiteURL = value; l\BVS)  
} p`mS[bxv!  
~3UQ|j  
{p)",)td  
public String getSFilePath() #,S0HDDHn  
{ P::TO-C  
return sFilePath; 9iXeBC  
} G3{Q"^S"  
rFIqC:=  
6,"IDH|ND  
public void setSFilePath(String value) 5j:0Yt  
{ w3#Wh|LQ-  
sFilePath = value; 7q?9Tj3  
} ` BDLW%aL  
L=c!:p|7)  
9)0D~oUi  
public String getSFileName() #OBJzf*p  
{ lwHzj&/ ~  
return sFileName; P.6nA^hXB  
} %dJX-sm@  
L>MLi3{  
qgE 73.!`6  
public void setSFileName(String value) k xP-,MD  
{ ^cV;~&|.Xk  
sFileName = value; $>*3/H  
} _Bj)r}~7#  
QN@CPuy  
t/ +=|*  
public int getNSplitter() `%CtWJ(e  
{ anIAM  
return nSplitter; ) u3 Zm  
} +hvO^?4j  
z)'Mk[  
Rz (QC\(  
public void setNSplitter(int nCount) umD!2 w  
{ km)zMoE{c{  
nSplitter = nCount; e&7JpT  
} ki[UV zd  
} 0.dgoq 3u  
=.y~fA!  
d_4T}% q  
/* }tsYJlh5  
**Utility.java }Mo=PWI1?  
*/ EPS={w$'s  
package NetFox; W.z;B<  
lCAIK  
ZaeqOVp/j  
public class Utility { L~(_x"uXd  
m0LTx\w!  
*\=.<|HZ  
public Utility() +u!0rLb  
{ Wm_4avXtO  
;FBUwR}  
0|2%vh>J  
} $wmvKQc{lx  
uIcn{RZ_z  
//线程睡眠 A'G66ei  
public static void sleep(int nSecond) " Om[~-31  
{ Y3r%B9~  
try{ 2rmSo&3@s  
Thread.sleep(nSecond); M>&%(4K  
} A:aE|v/T&  
catch(Exception e) :/:.Kb  
{ 8aO~/i:(.  
e.printStackTrace (); s_x:T<]  
} @7n/Q(  
} @kk4]:,w  
 -QOw8vm  
//日志 {LX.iH9}l  
public static void log(String sMsg)  Mu2  
{ Sl-v W  
System.err.println(sMsg); 4Fp0ZVT  
} z74in8]  
~vXaqCX  
4D[ '^q  
public static void log(int sMsg) =Vy`J)z9  
{ Yu?95qktP  
System.err.println(sMsg); <,3^|$c%  
} %6L^2 X  
} b8LoIY*  
fQL"O}Z  
1U^A56CN  
/* YhOlxON  
**TestMethod.java WA]c=4S  
*/ ]Tkc-ez  
package NetFox; q6_u@:3u  
JL\w_v  
5m?8yT}  
public class TestMethod { xqC+0{] y  
*.\  
@fs`=lL/  
public TestMethod() A3B56K  
{ ///xx/weblogic60b2_win.exe vk*=4}:  
try{ !PrwH;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _@ *+~9%8p  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); } b=}uiR#  
SiteFileFetch fileFetch = new SiteFileFetch(bean); X>NhZ5\  
fileFetch.start();  1WY/6[  
} COTp  
catch(Exception e){e.printStackTrace ();} 8<.C3m 6h  
66.5QD0  
0j30LXI_  
} )K,F]fc+O  
#<e\QE'!  
w"OP8KA:^T  
public static void main(String[] args) ua5OGx  
{ U f|> (C  
new TestMethod(); R,9[hNHWGs  
} 0A,]$Fzt  
} }?z@rt^  
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