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http断点续传简单实现(java)

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/* H&w:`JYDL3  
**SiteFileFetch.java +Dx1/I  
*/ gk!E$NyE  
package NetFox; Jv_.itc  
import java.io.*; C5O5S:|'  
import java.net.*; w5F4"nl#O}  
./'~];&  
FAQr~G}  
public class SiteFileFetch extends Thread { mu6039qy  
q"gqO%Wb|  
qP~WEcH`[  
SiteInfoBean siteInfoBean = null; //文件信息Bean ,?l~rc  
long[] nStartPos; //开始位置 _j:UGMTi(U  
long[] nEndPos; //结束位置 ;{<aA 5  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 )E'Fke  
long nFileLength; //文件长度 $& cz$jyY  
boolean bFirst = true; //是否第一次取文件 :J^qjAV  
boolean bStop = false; //停止标志 :ozV3`%$(  
File tmpFile; //文件下载的临时信息 vU=9ydAj?  
DataOutputStream output; //输出到文件的输出流 "$XYIuT  
:83,[;GO2  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) FJP< bREQ  
public SiteFileFetch(SiteInfoBean bean) throws IOException ?e F@Q !h  
{ )v[XmJ>H~o  
siteInfoBean = bean; di~]HUZh)  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); j|:dYt`WM  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); /b{o3, #.M  
if(tmpFile.exists ()) WtEI] WO  
{ |u@+`4o  
bFirst = false; :.*HQt9N  
read_nPos(); D`6iDi t  
} QX[Djz0H8  
else n[!;yO  
{ ;Vg^!]LL#  
nStartPos = new long[bean.getNSplitter()]; 1EVfowIl  
nEndPos = new long[bean.getNSplitter()]; ^>C 11v  
} +'%@!  
$}t=RW  
Pm4e8b  
3sH\1)Zz  
} 1N8;)HLIBJ  
Vy__b=ti?  
'T\dkSJv;V  
public void run() )2xE z  
{ {fZb@7?GF  
//获得文件长度 > 2#%$lX6  
//分割文件 '"y}#h__T  
//实例FileSplitterFetch R{HV]o|qk  
//启动FileSplitterFetch线程 R (G2qi  
//等待子线程返回 }91*4@B7  
try{ AXs=1  e  
if(bFirst) 5iVQc-m&  
{ ZWO)tVw9G  
nFileLength = getFileSize(); ; e@gO  
if(nFileLength == -1) Q]@c&*_|  
{ <3A0={En  
System.err.println("File Length is not known!"); 4'',6KJ@  
} >OV<_(S4  
else if(nFileLength == -2) nX|Q~x]  
{ +b^]Pz5  
System.err.println("File is not access!"); NUCiY\td  
} )l&D]3$6K  
else Hou*lCA  
{ t8QRi!\=  
for(int i=0;i<nStartPos.length;i++) @5xu>gKn  
{ (Yv{{mIy  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); iv*V#J>  
} .}q]`<]ze  
for(int i=0;i<nEndPos.length-1;i++) ;f:gX`"\  
{ +Mk#9 r  
nEndPos = nStartPos[i+1]; }Z\wH*s`  
} l<(cd,  
nEndPos[nEndPos.length-1] = nFileLength; >!L&>OOx  
} HTV ~?E  
} H3 , ut  
iK#/w1`  
`\bT'~P  
//启动子线程 ldGojnS  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; W^es;5  
for(int i=0;i<nStartPos.length;i++) VPt9QL(  
{ `5q ;ssu  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), yEq#Dr  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 5Fm av5  
nStartPos,nEndPos,i); 8TE>IPjm  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); {CtR+4KD  
fileSplitterFetch.start(); ]IZ>2!6r  
} ?s?$d&h  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), `9Yn0B.  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); (luKn&826  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 54{q.I@n  
nEndPos = " + nFileLength); +`B'r '  
// fileSplitterFetch[nPos.length-1].start(); $IVwA  
"X04mQn15  
 |t))u`~  
//等待子线程结束 * RWm47  
//int count = 0; |S&5es-yW  
//是否结束while循环 KB!5u9  
boolean breakWhile = false; i0:>Nk  
:]PM_V|  
P`S@n/}  
while(!bStop) +f>cxA  
{ glE^t6)  
write_nPos(); -Fxmsi  
Utility.sleep(500); x&Cp> +i  
breakWhile = true; ; Y"N6%  
2#vv$YD  
=wG+Ao  
for(int i=0;i<nStartPos.length;i++) Zp&@h-%YoD  
{ 9XLFHV("  
if(!fileSplitterFetch.bDownOver) !lTda<;]  
{ ('C7=u&F  
breakWhile = false; eS'yGY0b  
break; fKHE;A*>%  
} ,lt8O.h-l  
} t 9^A(Vh"-  
if(breakWhile) FY'ty@|_s  
break; c)}2K0  
#aar9  
&H||&Z[pk  
//count++; M6rc!K  
//if(count>4) >Kivuc  
// siteStop(); =8Ehrlq  
} }tG3tz0%fX  
 fvEAIs  
kL>d"w  
System.err.println("文件下载结束!"); @F~LW6K  
} x;LzG t:w  
catch(Exception e){e.printStackTrace ();} JWv{=_2w  
} J~#$J&iKh  
R"AUSO|{  
~+G#n"Pn  
//获得文件长度 `.%JjsD<  
public long getFileSize() !ABiy6d  
{ rJJ[X4$  
int nFileLength = -1; &QNY,Pj  
try{ aG+j9Q_  
URL url = new URL(siteInfoBean.getSSiteURL()); cXnKCzSxZq  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); -|S]oJy  
httpConnection.setRequestProperty("User-Agent","NetFox"); HYK!}&  
i3VW1~.8  
S'LZk9E  
int responseCode=httpConnection.getResponseCode(); *\uM.m0$  
if(responseCode>=400) K_/zuTy  
{ Dg HaOAdU  
processErrorCode(responseCode); 3;[DJ5  
return -2; //-2 represent access is error b:J(b?  
} MZ> 6o5K|  
p(F" /  
/9pM>Cd*Z  
String sHeader; IA&L]  
@n&<B`/  
tK(g-u0N`(  
for(int i=1;;i++) S4^N^lQ]  
{ c{+AJ8  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); }8-\A7T  
//Utility.log(in.readLine()); ? "/ fPV-  
sHeader=httpConnection.getHeaderFieldKey(i); Iu@y(wyg  
if(sHeader!=null) -r7]S  
{ SqA J-_~  
if(sHeader.equals("Content-Length")) A{eLl  
{ S8d8%R~1=h  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 5kypMHJm  
break; "=. t 36#  
} 20RXK1So  
} X-LA}YH=tS  
else 8.J( r(;>  
break; ;%C'FV e]  
} v``-F(i$  
} )E#2J$TD  
catch(IOException e){e.printStackTrace ();} oR1^/e  
catch(Exception e){e.printStackTrace ();} 5yZTcS z  
Z?P~z07  
nl aM  
Utility.log(nFileLength); lv&mp0V+  
 +=q)  
YgUH'P-  
return nFileLength; WE6a'  
} B/JO~;{  
v1JS~uDz  
7dG 79H  
//保存下载信息(文件指针位置) Ys+OB*8AE  
private void write_nPos() H5CR'Rp  
{ $?G"GQ!.  
try{ g>rp@M  
output = new DataOutputStream(new FileOutputStream(tmpFile)); m([(:.X/IX  
output.writeInt(nStartPos.length); oX@ya3!Pz  
for(int i=0;i<nStartPos.length;i++) )tHaB,  
{ kum#^^4G|  
// output.writeLong(nPos); ^N}Wnk7ks'  
output.writeLong(fileSplitterFetch.nStartPos); &3F}6W6A  
output.writeLong(fileSplitterFetch.nEndPos); OO dSKf8  
} 7?8wyk|x  
output.close(); {5r0v#;  
} DZ7 gcC  
catch(IOException e){e.printStackTrace ();} .d;Iht,[  
catch(Exception e){e.printStackTrace ();} $ ,SF@BhO  
} {GDmVWG0q  
mR\`DltoV  
:F,O  
//读取保存的下载信息(文件指针位置) PNF?;*`-{7  
private void read_nPos() SzwQOs*  
{ W7"{r)7  
try{ 7|\@zQ h   
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); `\`>0hlu  
int nCount = input.readInt(); vu!d)Fy  
nStartPos = new long[nCount]; n79QJl/  
nEndPos = new long[nCount]; p.I.iAk%G^  
for(int i=0;i<nStartPos.length;i++) 7(M(7}EKA  
{ eI.2`)>  
nStartPos = input.readLong(); $Nrm!/)*'}  
nEndPos = input.readLong(); HoV^Y6  
} d)cOhZy  
input.close(); EN{]Qb06A  
} !Cgx.   
catch(IOException e){e.printStackTrace ();} 4(}J.-B  
catch(Exception e){e.printStackTrace ();} D(p\0V  
} '7wd$rl  
\!IMaB]  
2sNK  
private void processErrorCode(int nErrorCode) LMi:%i%\  
{ >Rvx[`|O!m  
System.err.println("Error Code : " + nErrorCode); JO=[YoTr  
} Djk C  
Uz cx6sw  
2%*MW"Q  
//停止文件下载 {oc igR 0  
public void siteStop() E$9 Ys  
{ HEL!GC>#  
bStop = true; c_aZ{S  
for(int i=0;i<nStartPos.length;i++) 5D M"0  
fileSplitterFetch.splitterStop(); MuoF FvAA  
g%F"l2M  
~\x:<)  
} &l$Q^g  
} 1O].v&{  
//负责部分文件的抓取 kGpa\c g1  
**FileSplitterFetch.java (b?{xf'G  
*/ +3s%E{  
package NetFox; 43?^7_l-  
_&K  
08X_}97#WF  
import java.io.*; j!7`]  
import java.net.*; y4h=Lki@  
EbeI{ -'aF  
[E#UGJ@  
public class FileSplitterFetch extends Thread { &g2 Eptx#  
G}5#l  
x^Yl*iq  
String sURL; //File URL %Qg+R26U  
long nStartPos; //File Snippet Start Position hcVJBK  
long nEndPos; //File Snippet End Position eh1Q7 ~  
int nThreadID; //Thread's ID  ^p n(=4  
boolean bDownOver = false; //Downing is over 1qV@qz  
boolean bStop = false; //Stop identical ^[%%r3"$C  
FileAccessI fileAccessI = null; //File Access interface V8eB$in  
ZmOfEg|h\  
.B#l5pfvP  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException 3@5=+z~CW  
{ %m:m}ziLQ  
this.sURL = sURL; G-9iowS/A  
this.nStartPos = nStart; l5l>d62  
this.nEndPos = nEnd; SIBoCs5  
nThreadID = id; eEhr140  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 qV5DW0.  
} G=;k=oX(  
`eu9dLz H  
.NtbL./=|  
public void run() .0R v(Y  
{ s2j['g5  
while(nStartPos < nEndPos && !bStop) {3N'D2N  
{  L4uFNM]  
eZ"1gYqy  
Bgmn2-  
try{ E}%hz*Q)(  
URL url = new URL(sURL); R/"x}B1d  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); qfcYE=  
httpConnection.setRequestProperty("User-Agent","NetFox"); P0 `Mdk371  
String sProperty = "bytes="+nStartPos+"-"; Y(.OF Q  
httpConnection.setRequestProperty("RANGE",sProperty); AoA!q>  
Utility.log(sProperty); WyP W*  
099sN"kf  
~=R SKyzt  
InputStream input = httpConnection.getInputStream(); q80S[au  
//logResponseHead(httpConnection); =] 3tUD  
?\8?%Qk  
D&HV6#  
byte[] b = new byte[1024]; FI"`DMb}  
int nRead; s1?[7yC  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) E( us'9c   
{ vkLC-Mzm<  
nStartPos += fileAccessI.write(b,0,nRead); bQ|V!mrN}  
//if(nThreadID == 1) 1s1=rZ!  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); v&Kqq!DE  
} !mXxAo  
=@F&o4)r  
r-,e;o>9  
Utility.log("Thread " + nThreadID + " is over!"); AIA6yeaU  
bDownOver = true; 7)h[Zy,A  
//nPos = fileAccessI.write (b,0,nRead); pLv$\ MiZ  
} ;-UmY}MU  
catch(Exception e){e.printStackTrace ();} g/13~UM\  
} I(=V}s2  
} QRLt9L  
2w)-\/j}  
> x IJE2  
//打印回应的头信息 ja=F7Usb  
public void logResponseHead(HttpURLConnection con) YJ(*wByM  
{ G%d (  
for(int i=1;;i++) ioPUUUb)  
{ yoAfc  
String header=con.getHeaderFieldKey(i); |p$spQ  
if(header!=null) %'0T Xr$  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); q\\gpCgp  
Utility.log(header+" : "+con.getHeaderField(header)); M:5b4$Qh<  
else .jMq  
break; }MUn/ [x  
} gk`zA  
} +**!@uY  
'=P7""mN5  
%,ngRYxT#  
public void splitterStop() JmEj{K<3I  
{ F:mq'<Q  
bStop = true; 0Ia($.1mY  
} q\H[am  
,]b~t0|B  
k%^lF?_0I  
} tDAhyy73  
3j3N!T9  
Fv<`AU  
/* vzmc}y G  
**FileAccess.java x`6<m!d`  
*//文件访问(定位,写) ]vuwkn+)  
package NetFox; _ 84ut  
import java.io.*; /rSH"$  
Ks}Xgc\  
A/`%/0e   
public class FileAccessI implements Serializable{ %\i9p]=  
n@G[  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >ooZj9:'  
RandomAccessFile oSavedFile; "n*~Mj Ny  
long nPos; Z(!00^  
o6//IOZ  
"W(Q%1!Wi  
public FileAccessI() throws IOException CW<N: F.9  
{ wb~@7,D  
this("",0); J:skJ.Wx  
} I[n ^{8gz  
UT="2*3gz  
S]E.KLR?[;  
public FileAccessI(String sName,long nPos) throws IOException ur$l Z0  
{ [|l?2j\  
oSavedFile = new RandomAccessFile(sName,"rw"); r;m)nRu  
this.nPos = nPos; t'ZWc\  
oSavedFile.seek(nPos); )aX,%yK  
} 6S~sVUL9`  
V%Sy"IG  
EAeqLtFqs  
public synchronized int write(byte[] b,int nStart,int nLen) |<O9Sb_  
{ t:fFU1x  
int n = -1; Q?X>E3=U  
try{ + T8B:  
oSavedFile.write(b,nStart,nLen); uw2hMt (N  
n = nLen; D.mHIsX6\  
}  }K3x  
catch(IOException e) >a}f{\Q  
{ @/ k@WhFZ  
e.printStackTrace (); 5ms""LD/  
}  @Pt="*g  
GH[wv<  
]7e =fM9V;  
return n; hqRw^2F  
} 6"}?.E$  
}3?n~s\)6f  
@lvyDu6e  
} "Y\_TtY  
#UbF9})q  
7NJhRz`_  
/* R+CM`4CD  
**SiteInfoBean.java O|w J)  
*/ nR`ov1RH  
package NetFox; ;amXY@RmH  
w}=5ElB  
!o$!Frc  
public class SiteInfoBean { aE2.L;Tk?  
t]-5 ]oI  
x*/S*!vx\  
private String sSiteURL; //Site's URL oJfr +3I  
private String sFilePath; //Saved File's Path F;]%V%F.X  
private String sFileName; //Saved File's Name -a-(r'Qc(  
private int nSplitter; //Count of Splited Downloading File [Jv@J\  
=%/)m:f!^  
YIjTL!bA"  
public SiteInfoBean() GI&h`X5,e  
{//nSplitter的缺省值为5 KVJ_E!i  
//default value of nSplitter is 5  f& CBU  
this("","","",5);  #B\" '8#  
} AA7C$;Z15~  
pa# IJ  
s;A@*Y;v  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) )6aAB|  
{ r9dyA5oD  
sSiteURL= sURL; f`Fi#EKT  
sFilePath = sPath; zE_i*c"`  
sFileName = sName; Sm5H_m!  
this.nSplitter = nSpiltter; ' MxrQ;|S  
,S!azN=  
}+sT4'Ah>  
} Er{>p|n =  
1@-Ns  
<%" b9T`'  
public String getSSiteURL() hq #?kN  
{ ?F3h)(}  
return sSiteURL; G nG>7f[v  
} qo|WXwP2  
aca=yDs2  
}B1!gz$YNO  
public void setSSiteURL(String value) g pOC`=  
{ 1aTB%F  
sSiteURL = value; V=*wKuB  
} RVQh2'w  
=z /dcC$r  
bR)(H%I  
public String getSFilePath() aYSCw 3C<  
{ )<tI!I][j  
return sFilePath; @qYp>|AF  
} q0zr E5  
^=-y%kp"  
sc,vj'r  
public void setSFilePath(String value) 2_Z ? #Y  
{ +csi[c)3E  
sFilePath = value; {Sj9%2'M)  
} AnX%[W "  
&eX!#nQ_.  
Ob<{G"  
public String getSFileName()  e0,|Wm  
{ "9Q40w\  
return sFileName; OD!& .%  
} WL"^>[Vq  
SR |`!  
W~7A+=&  
public void setSFileName(String value) ~XmLX)vO/  
{ $arK(  
sFileName = value; 9j6QX ~,  
} 1^}[&ar  
`M^= D&Bf  
4J/}]Dr5  
public int getNSplitter()  abfW[J  
{ 4p,EBn9(  
return nSplitter; ~yW4)4k;b  
} "ozr+:#\  
;"~ fZ2$U  
2Tp1n8FV  
public void setNSplitter(int nCount) M:[ %[+6  
{ I7n"&{s"*  
nSplitter = nCount; (<xfCH F5  
} EWkLXU6t  
} @a0DT=>dT  
Ni-xx9)=  
9\BT0kx  
/* [`"ZjkR_J  
**Utility.java .ufTQ?Fe  
*/ zv\kPfGDK  
package NetFox; AW!?"xdZ  
n%.7h3  
@v)p<r^M">  
public class Utility { :2rZcoNb.  
8"8t-E#?  
oldA#sA$  
public Utility() Ki$MpA3j   
{ PIoLywpRn  
SBfT20z[  
yDegcAn?  
} Kzm+GW3o[  
AicBSqUke  
//线程睡眠 3yU.& k  
public static void sleep(int nSecond) (mTE;s(  
{ lvBx\e;7P  
try{ koZ*+VP=  
Thread.sleep(nSecond); jD<{t  
} uXJ;A *  
catch(Exception e) vZaZc}AyL  
{ U4C 9<h&  
e.printStackTrace (); Gi?/C&1T  
} V)~.~2$  
} QSdHm  
v4`"1Ss,K  
//日志 AQ,' 6F9  
public static void log(String sMsg) '$ =>  
{ Mh:L$f0A%O  
System.err.println(sMsg); l3Q(TH~I  
} #*K}IBz  
8<pzb}xK  
p6#g;$V$  
public static void log(int sMsg) i1NY9br  
{ D%OQ e#!  
System.err.println(sMsg); r%yvOF\>  
} ~=6xyc/c  
} +eK"-u~K  
aW)-?(6>  
mD$A4Y-'p  
/* >~[c|ffyo/  
**TestMethod.java H8Bs<2  
*/ }Qn&^[[miL  
package NetFox; Dwr)0nk  
F;4vPbH+  
)U7t  
public class TestMethod { a!7A_q8M  
?(D q?-.  
VM GS[qrG  
public TestMethod() - D  
{ ///xx/weblogic60b2_win.exe !;Yg/'vD-  
try{ cl=EA6P\X  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); [!HEQ8 2g  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); "GMBjT8  
SiteFileFetch fileFetch = new SiteFileFetch(bean); P;=n9hgHI  
fileFetch.start(); f332J  
} SPX$ U5&  
catch(Exception e){e.printStackTrace ();} Z_};|B}  
=9O^p@Q#W  
WM7oM~&{6  
} 4B =7:r  
R_W+Ylob  
*4Thd:7 `  
public static void main(String[] args) GK )?YM  
{ BP'36?=Zo  
new TestMethod(); -3t7*  
} \qdHX  
} s C%&cRQD  
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