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http断点续传简单实现(java)

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/* p\p\q(S">  
**SiteFileFetch.java V\]" }V)"  
*/ FLZWZ;  
package NetFox; S4CbyXW  
import java.io.*; ln!'_\{  
import java.net.*; crcA\lJf  
(u3s"I d  
"2?l{4T\  
public class SiteFileFetch extends Thread { 23!;}zHp  
o|BP$P8V  
hm*cw[#O1x  
SiteInfoBean siteInfoBean = null; //文件信息Bean 1oLv.L  
long[] nStartPos; //开始位置 D*PYr{z'  
long[] nEndPos; //结束位置 O81X ;JdP3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 errH>D~  
long nFileLength; //文件长度 & fC!(Oy  
boolean bFirst = true; //是否第一次取文件 DZS]AC*  
boolean bStop = false; //停止标志 BYrZEVM9  
File tmpFile; //文件下载的临时信息 :1ecx$  
DataOutputStream output; //输出到文件的输出流 :}:3i9e*2  
@|}BXQNd  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) +|iYg/2  
public SiteFileFetch(SiteInfoBean bean) throws IOException AK!hK>u`  
{ }n_p$g[Nj/  
siteInfoBean = bean; ;Q;[*B=kE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); l_tw<`Ep  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %V`F!D<D  
if(tmpFile.exists ()) #H?t!DU  
{ !$;a[Te  
bFirst = false; YgUH'P-  
read_nPos(); *l+OlQI0+  
} ?>c=}I#Ui-  
else >LC<O.  
{ xo}b= v  
nStartPos = new long[bean.getNSplitter()]; 2& PPz}Sw  
nEndPos = new long[bean.getNSplitter()]; iD38\XNMV  
} mW2,1}Jv  
qBV x6MI  
YTQt3=1ii  
"@A![iP  
} 57a2^  
f3j{VN  
GQQ.OvEc  
public void run() 9>zcBG8f  
{ j$UV/tp5T  
//获得文件长度 2aw&YZ&Xo  
//分割文件 #`TgZKDg2  
//实例FileSplitterFetch TGXa,A{  
//启动FileSplitterFetch线程 B vo5-P6XY  
//等待子线程返回 >(w2GD?  
try{ `afIYXP  
if(bFirst) U[L9*=P;  
{ RO;Bl:x4  
nFileLength = getFileSize(); p(;U@3G  
if(nFileLength == -1) do*}syQ`O  
{ I:bD~F b3  
System.err.println("File Length is not known!"); vu!d)Fy  
} n79QJl/  
else if(nFileLength == -2) ;8WZx  
{ T{qTj6I  
System.err.println("File is not access!"); H1GRMDNXOA  
} %W,D;?lEo>  
else X"gCR n%tn  
{ A[IL H_w  
for(int i=0;i<nStartPos.length;i++) NjPDX>R\K  
{ =deMd`=J  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); b`yZ|j'ikd  
} ^-mRP\5  
for(int i=0;i<nEndPos.length-1;i++) sDr/k`>  
{ SG}V[Glk  
nEndPos = nStartPos[i+1]; Gb[`R}^dq  
} 6qN~/TnHZ  
nEndPos[nEndPos.length-1] = nFileLength; Spo?i.#  
} :j|IP)-f  
} 8l}1c=A}Vi  
dzK{ Z  
w -Nhs6  
//启动子线程 Ol"3a|  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; MuoF FvAA  
for(int i=0;i<nStartPos.length;i++) g%F"l2M  
{ g (VNy@  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), (,^*So/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), .=m,hu~  
nStartPos,nEndPos,i); x!\ONF5$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); oH0X<'  
fileSplitterFetch.start(); 43?^7_l-  
} _&K  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), |KB0P@=a  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); :m86 hBE.  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", D=:04V}2+  
nEndPos = " + nFileLength); !D!~ ^\  
// fileSplitterFetch[nPos.length-1].start(); hA\K</h.  
[."[pY  
`V)Z)uN{0  
//等待子线程结束 pa}*E  
//int count = 0; Z_\C*^  
//是否结束while循环 ?JL7=o X  
boolean breakWhile = false; J=.`wZQkS  
dz~co Z9  
{t};-q!v$j  
while(!bStop) qE'9QQ>:b  
{ e8YMX&0%  
write_nPos(); m<L;  
Utility.sleep(500); rc+C?)S  
breakWhile = true; =rdY @  
1&fc1uYB4  
3=-4%%[M@  
for(int i=0;i<nStartPos.length;i++) G-9iowS/A  
{ l5l>d62  
if(!fileSplitterFetch.bDownOver) SIBoCs5  
{ eEhr140  
breakWhile = false; \!]Ua.e<  
break; BBcV9CGU  
} LZMYr  
} hhoEb(BA  
if(breakWhile) Y#!h9F  
break; 4f(Kt,0  
6} FO[  
%OgS^_tu  
//count++; Sq:0w  
//if(count>4) $}")1|U,X  
// siteStop(); As+t##gN  
} kB5.(O  
NrP0Ep%V  
p ?wI9GY  
System.err.println("文件下载结束!"); '`1CBU$  
} 7d92 Pe  
catch(Exception e){e.printStackTrace ();} Qt]Q: 9I[  
} e #/E~r&  
.9O$G2'oh  
1-.~7yC  
//获得文件长度 r J KZ)N{  
public long getFileSize() ? FfC  
{ ]Qm]I1P  
int nFileLength = -1; @ 49nJi  
try{ VLBE'3Qg 1  
URL url = new URL(siteInfoBean.getSSiteURL()); 5k|9gICyd*  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); i-yy/y-N  
httpConnection.setRequestProperty("User-Agent","NetFox"); @ P|LLG'  
OFje+S  
1Bxmm#  
int responseCode=httpConnection.getResponseCode(); r! Ay :r  
if(responseCode>=400) Y.^=]-n,  
{ dMR3)CO  
processErrorCode(responseCode); lI>SUsQFfm  
return -2; //-2 represent access is error a<]B B$~  
} g/13~UM\  
I(=V}s2  
QRLt9L  
String sHeader; OT'[:|x ;  
> x IJE2  
ja=F7Usb  
for(int i=1;;i++) 1~ $);US  
{ wcDRH)AW.  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); m|OO,gR  
//Utility.log(in.readLine()); h$L"8#  
sHeader=httpConnection.getHeaderFieldKey(i); RmZ]" `  
if(sHeader!=null) mDZ*E!B  
{ tE7[Smzuf  
if(sHeader.equals("Content-Length")) d\|!Hg,  
{ \c^45<G2qA  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); V ]90  
break; v9T_&  
} v@#b}N0n  
} 3]?#he  
else %Qk/_ R1   
break; LkQX?2>]  
} O9:U8$*  
} Ali9pvE  
catch(IOException e){e.printStackTrace ();} y!]CJigpZ  
catch(Exception e){e.printStackTrace ();} ExRe:^yU\  
?k(\ApVHj  
epgPT'^  
Utility.log(nFileLength); sUPz/Z.h  
@?"h !fyu  
KN-avu_Ix  
return nFileLength; mS0udHod  
} }`+B=h-dW  
``E/m<r:$  
}<'5 z qS  
//保存下载信息(文件指针位置) F5o+kz$;  
private void write_nPos() .KdyJ6o  
{ } (!EuLL  
try{ }%D^8>S  
output = new DataOutputStream(new FileOutputStream(tmpFile)); LY+|[qka  
output.writeInt(nStartPos.length); |*`Z*6n  
for(int i=0;i<nStartPos.length;i++) 0?>dCu\  
{ c&L"N!4z  
// output.writeLong(nPos); d:yqj:  
output.writeLong(fileSplitterFetch.nStartPos); ~Ch+5A;  
output.writeLong(fileSplitterFetch.nEndPos); *}8t{ F@k  
} W0}B'VS.I  
output.close(); qoAj] ")  
} c_elShK8#  
catch(IOException e){e.printStackTrace ();} MTUn3;c/  
catch(Exception e){e.printStackTrace ();} 6d+p7x  
} Afk$?wkL  
yV^s,P1  
Uk\Id ~xLV  
//读取保存的下载信息(文件指针位置) H<1WbM:w  
private void read_nPos() S6[v;{xJ  
{ >|;aIa@9  
try{ EAeqLtFqs  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); |<O9Sb_  
int nCount = input.readInt(); t:fFU1x  
nStartPos = new long[nCount]; Q?X>E3=U  
nEndPos = new long[nCount]; @$T 9Ll  
for(int i=0;i<nStartPos.length;i++) *&f$K1p  
{ `Qqk<o  
nStartPos = input.readLong(); W2.qhY5  
nEndPos = input.readLong(); vv=VRhwF  
} `UBYp p  
input.close(); gJM`[x`T  
} (T2m"Yi:  
catch(IOException e){e.printStackTrace ();} r7',3V  
catch(Exception e){e.printStackTrace ();} /B}lO0]:  
} ~9j%Hm0ht  
?@V[#.  
FHV-BuH5  
private void processErrorCode(int nErrorCode) ^+g$iM[`f  
{ jRL<JZ1N  
System.err.println("Error Code : " + nErrorCode); J(6oL   
} i'\T R|qd  
u7=U^}#  
[}&Sxgv  
//停止文件下载 >KJ+-QuO&  
public void siteStop() ) Yd?m0m*  
{ r\/+Oa'  
bStop = true; M|R b&6O  
for(int i=0;i<nStartPos.length;i++) F+u|HiYG  
fileSplitterFetch.splitterStop(); ,{c?ymw?  
>;[*!<pfK5  
Phke`3tth  
} @*sWu_ -Y%  
} 4t)/  
//负责部分文件的抓取 AF%@VLf  
**FileSplitterFetch.java GI&h`X5,e  
*/ KVJ_E!i  
package NetFox;  f& CBU  
8w.YYo8`  
AA7C$;Z15~  
import java.io.*; pa# IJ  
import java.net.*; s;A@*Y;v  
cb}[S:&|  
r9dyA5oD  
public class FileSplitterFetch extends Thread { ow]053:i  
MNV % =G  
Gh}*q|Lz  
String sURL; //File URL ukUGvK  
long nStartPos; //File Snippet Start Position v\{!THCSh  
long nEndPos; //File Snippet End Position vuYSVI2=H  
int nThreadID; //Thread's ID O6OP =K!t:  
boolean bDownOver = false; //Downing is over F|!){=   
boolean bStop = false; //Stop identical 1@-Ns  
FileAccessI fileAccessI = null; //File Access interface <%" b9T`'  
hq #?kN  
\o^2y.q:>  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException j*vYBGD  
{ #Q /Arq  
this.sURL = sURL; sQ\8>[]   
this.nStartPos = nStart; *Em,*!  
this.nEndPos = nEnd; ,KFapz!  
nThreadID = id; tdu$pC6  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 p}~qf  
} % oo2/aF  
pJtex^{!:  
%ALwz[~]  
public void run() 1{JV}O  
{ ;&)-;l7M  
while(nStartPos < nEndPos && !bStop) WILMH`  
{ >=-(UA  
hr)B[<9  
aYSCw 3C<  
try{ t)}scf&^x  
URL url = new URL(sURL); ;-qO'V:;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ~W-PD  
httpConnection.setRequestProperty("User-Agent","NetFox"); Uw7h=UQh  
String sProperty = "bytes="+nStartPos+"-"; ~ (jKz}'~U  
httpConnection.setRequestProperty("RANGE",sProperty); MpR2]k#n<  
Utility.log(sProperty); HKUn`ng  
b"{'T]"*j  
N=7pK&NHSG  
InputStream input = httpConnection.getInputStream(); k-^mIJo}  
//logResponseHead(httpConnection); 5f 5f0|ok  
:w^Ed%>y7  
, JQp'e  
byte[] b = new byte[1024]; ]'=)2 .}  
int nRead; W}mn}gTQ  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) >: g3k  
{ R)m'lMi|  
nStartPos += fileAccessI.write(b,0,nRead); \r+8qC[,  
//if(nThreadID == 1) BNs@n"k  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); V6,H}k   
} fd.^h*'mU  
OL^l 3F  
,]d /Q<  
Utility.log("Thread " + nThreadID + " is over!"); @W"KVPd  
bDownOver = true; z+n,uHs  
//nPos = fileAccessI.write (b,0,nRead); Jh!I:;/  
} )`(p9@,V  
catch(Exception e){e.printStackTrace ();} #$8% w  
} 2HsLc*9{4  
} wG-HF'0L  
Rx=>6,)'  
YOmM=X+'H  
//打印回应的头信息 >]vlkA(  
public void logResponseHead(HttpURLConnection con) -^hWM}F  
{ f@|A[>"V  
for(int i=1;;i++) Lo N< oj5  
{ i\rDu^VQ  
String header=con.getHeaderFieldKey(i); eEv@}1~  
if(header!=null) =*c7i]@}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); 2$g6}A`r  
Utility.log(header+" : "+con.getHeaderField(header)); %|q>pin2  
else CU@Rob}s  
break; %D%8^Zd_  
} 1e{IC=  
} MS 81sN\d  
'6cWS'9"  
BMG3|N^  
public void splitterStop() YSic-6z0Ms  
{ q=Sgk>NA  
bStop = true; Rnr(g;2  
} v50bdj9}k  
qzKdQ&vO  
i%#+\F.&  
} :*Z4yx  
%\dz m-d(C  
- -HZX  
/* .*Ct bGw  
**FileAccess.java zuJ@E=7  
*//文件访问(定位,写)  #~2%)  
package NetFox; pz\ +U7  
import java.io.*; D%OQ e#!  
lm-dW'7&  
[B#R94  
public class FileAccessI implements Serializable{ Vt %bI0#  
-.u]GeMy  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8 D3OOab  
RandomAccessFile oSavedFile; 1PQ~jfGi  
long nPos; .oYl-.E>&  
Z<1FSk,[  
Ui_8)z _  
public FileAccessI() throws IOException eg\v0Y!rI  
{ la0BiLzb]  
this("",0); JQ8fdP A  
} SPX$ U5&  
8<S~Z:JK  
C*)3e*T*  
public FileAccessI(String sName,long nPos) throws IOException LtWP0@JA  
{ =n5zM._S-  
oSavedFile = new RandomAccessFile(sName,"rw"); %p^wZtm  
this.nPos = nPos; [YF>:ydk  
oSavedFile.seek(nPos); +Mo9kC  
} y~ AVei&  
0=@?ob7  
@r/#-?W  
public synchronized int write(byte[] b,int nStart,int nLen) Q]Y*K  
{ 2,$8icM  
int n = -1; L[oui,}_  
try{ &zl|87M  
oSavedFile.write(b,nStart,nLen); kO.%9wFbz  
n = nLen; >Wm `v.-  
}  8n#HFJ~  
catch(IOException e) @Lpq~ 1eZB  
{ aktU$Wbwl  
e.printStackTrace (); |%F=po>w  
} rn/ /%  
<r .)hT"0  
bR*-Ht+wd  
return n; KyVQh8  
} 8 ##-EN;ag  
#a/5SZP Z\  
9oRy)_5Z(=  
} 7`- Zuf  
V]|^&A _c  
Q8:Has  
/* !o5 W  
**SiteInfoBean.java ^W`<gR  
*/ 9_q#W'/X  
package NetFox; Jj>?GAir  
0[R L>;D:  
*rM^;4Zt  
public class SiteInfoBean { $*^kY;  
r54&XE]O  
09X01X[  
private String sSiteURL; //Site's URL hEA<o67  
private String sFilePath; //Saved File's Path :By?O"LQ  
private String sFileName; //Saved File's Name R+2+-j4  
private int nSplitter; //Count of Splited Downloading File RJL2J]*S  
X\]L=>]C  
ZOft.P O  
public SiteInfoBean() $h2){*5E{  
{//nSplitter的缺省值为5 j>*R]mr6  
//default value of nSplitter is 5 zcel|oz)  
this("","","",5); u8gS< \  
} <LmIK  
-l`f)0{  
wm]^3q I2  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &Ts-a$Z7?S  
{ zV:pQRbt.  
sSiteURL= sURL; W4[V}s5u  
sFilePath = sPath; (EK"V';   
sFileName = sName; u1t% (_h  
this.nSplitter = nSpiltter; Ae69>bkE0  
=g/{%;  
SfgU`eF%B  
} mu?Eco`~  
7s"< 'cx_F  
3BB%Z 6F  
public String getSSiteURL() A'G66ei  
{ ktj]:rCkF  
return sSiteURL; KC(xb5x Y  
} U Z.=aQ}M  
V2$h8\a  
b'J'F;zh>  
public void setSSiteURL(String value) )jkXS TZ  
{ A/s>PhxV  
sSiteURL = value; Ul2R'"FB  
} AgV G`q  
R&|mdY8  
Vy*:ne  
public String getSFilePath() ~.A)bp  
{ Mr?Xp(.}G  
return sFilePath; ox:[f9.5  
} GDu~d<RH  
5QPM t^  
*.\  
public void setSFilePath(String value) v z^<YZMu  
{ *H?!;u=8  
sFilePath = value; bx]N>k J  
} \2ZPj)&-E  
bHg,1y)UC  
COTp  
public String getSFileName()  PZ{Dv'C  
{ FDVcow*]n  
return sFileName; w=^`w:5X  
} 6)vSG7Ise  
9:`(Q3Ei  
U f|> (C  
public void setSFileName(String value) TJ: ]SB  
{ .A-]_98Z  
sFileName = value; ]Ar\c["  
} pGf@z:^{*-  
v2H#=E4cZ#  
uiJS8(Cb  
public int getNSplitter() OCZ[D{i9@  
{ ZO4*sIw%  
return nSplitter; %^1cyk  
} K_2|_MLlZ  
E<C&Cjz:H  
_U{zMVr  
public void setNSplitter(int nCount) >. '<J]  
{ L0&RvI#  
nSplitter = nCount; 2gzou|Y  
} ]J:1P`k.  
} }~"hC3w  
ZTU&, 1Y;  
~(pmLZ<GW}  
/* ' v\L @"  
**Utility.java "TUe%o  
*/ :$_6SQ<?  
package NetFox; >m# e:[N  
j'aHF#_  
HAv{R!*  
public class Utility { zGc: @z  
)u/H>;L P  
OM|Fwr$  
public Utility() 4<cz--g  
{ Q}!mx7b0]  
#7ov#_2Jd  
^{xeij/  
} c-g)eV|)S  
(`6T&>(4  
//线程睡眠 NTS# sgP  
public static void sleep(int nSecond) "Vr[4&`  
{ p/2jh&  
try{ &f7fK|}  
Thread.sleep(nSecond); "dROb}szn  
} @^;j)%F}  
catch(Exception e) w|CZ7|6  
{ RGn!{=  
e.printStackTrace (); W`"uu.~f  
} "wlt> SU  
} I+!:K|^  
 Y!WG)u5  
//日志 P7 PB t  
public static void log(String sMsg) ?-tVSRKQ  
{ R(-<BtM!-  
System.err.println(sMsg); Ja SI^go  
} N`E-+9L)  
h'$QC )P  
ifo7%XPcg  
public static void log(int sMsg) RJy=pNztm  
{ ]r3Kg12Mi  
System.err.println(sMsg); :5/Uh/sX  
} >6oOZbUY0  
} (;%|-{7e-  
,+g&o^T  
Dw7vv]+ S  
/* EwS!]h?  
**TestMethod.java `]LSbS  
*/ or k=`};  
package NetFox; XyMG.r-,  
[]0mX70N  
RNPbH.  
public class TestMethod { 7~ztwL  
A~Xq,BxCV  
15$4&=O  
public TestMethod() T6pLoaKu  
{ ///xx/weblogic60b2_win.exe 0aoHKeP  
try{ v|ox!0:#  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); JbO ~n )%x  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); }tPk@$  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ]I/Vbs  
fileFetch.start(); pG^}Xf2a  
} |3+m%;X  
catch(Exception e){e.printStackTrace ();} kkvtB<<Y  
r-kMLw/)  
{B*W\[ns  
} ]O{u tm  
okq[ o90  
r}u%#G+K,  
public static void main(String[] args) hF3&i=;.  
{  q{die[J  
new TestMethod(); x90jw$\%7  
} 5 cK@WE:  
} #a| L3zR5v  
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