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http断点续传简单实现(java)

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/* mm;sf  
**SiteFileFetch.java LI].*n/v  
*/ `]^W#6l  
package NetFox; XJ5@/BW  
import java.io.*; '$),i>6gJ  
import java.net.*;  TD%&9$F  
)Xa_ry7  
05g %5vHF  
public class SiteFileFetch extends Thread { sC0u4w>Y  
Vl;zd=  
fvk(eWB  
SiteInfoBean siteInfoBean = null; //文件信息Bean 6%}`!_N<Mc  
long[] nStartPos; //开始位置 U p6OCF  
long[] nEndPos; //结束位置 NfnPXsad  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 @T:J<,  
long nFileLength; //文件长度 *<X1M~p$  
boolean bFirst = true; //是否第一次取文件 ',K:.$My  
boolean bStop = false; //停止标志 i I`vu  
File tmpFile; //文件下载的临时信息 rVP{ ^Jdo  
DataOutputStream output; //输出到文件的输出流 'v9M``  
zw+RDo  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) M\-[C!h,  
public SiteFileFetch(SiteInfoBean bean) throws IOException b3FKDm[  
{ R:$E'PSx  
siteInfoBean = bean; b b.UtoPz  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); m2"wMt"*V  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ` Nf  
if(tmpFile.exists ()) I=:"Fqj'N  
{ dr c-5{M  
bFirst = false; TW!OE"B  
read_nPos(); tGU~G&  
} 6 Ia HaV+P  
else 3n)$\aBE  
{ K_~kL0=4  
nStartPos = new long[bean.getNSplitter()]; _VVq&t}  
nEndPos = new long[bean.getNSplitter()]; _",< at  
} l i)6^f#  
L""ZI5J{F9  
J]#rh5um  
Z,O* p,Gzn  
} FzcXSKHV %  
0|.jIix;  
I;-Y2*  
public void run() oyr b.lu/  
{ Q4_r) &np  
//获得文件长度 o$eCd{HuX  
//分割文件 ;mT}Q;F#  
//实例FileSplitterFetch q/@+.q  
//启动FileSplitterFetch线程 $}{[_2  
//等待子线程返回 Vjs'|%P7  
try{ {kw% 7}!  
if(bFirst) &bz% @p;  
{ }I-nT!D'y  
nFileLength = getFileSize(); 3}!u8,P  
if(nFileLength == -1) "w%:5~u 9  
{ "[!b5f3!I  
System.err.println("File Length is not known!"); ' tY(&&  
} +<.o,3  
else if(nFileLength == -2) LRts W(A/  
{ !^&VZh  
System.err.println("File is not access!"); 9 :Oz-b  
} oKsArZG  
else ?&-1(&  
{ #Tei0B7  
for(int i=0;i<nStartPos.length;i++) ,h*N9}xYTi  
{ rJkJ/9s  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); :\JCxS=EW  
} \ a,}1FS  
for(int i=0;i<nEndPos.length-1;i++) m$=}nI(H  
{ >mX6;6FF  
nEndPos = nStartPos[i+1];  5{oc  
} }oA>0Nw$K  
nEndPos[nEndPos.length-1] = nFileLength; )WbWp4  
} C1e@{>  
} ]95VM yN  
`BKb60  
; cvMNU$fN  
//启动子线程 | bRU=dg  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; [K$5 Rm5  
for(int i=0;i<nStartPos.length;i++)  $8rnf  
{ '(FC  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), IycZ\^5*-  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), [#mk TY  
nStartPos,nEndPos,i); N|$9v{ j_  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ~HhB@G!3  
fileSplitterFetch.start(); #Zw:&' QB  
} Bh' fkW3  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), @, GL&$Y:W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); \Q(a`6U  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Lv]%P.=[G  
nEndPos = " + nFileLength); "A"YgD#t  
// fileSplitterFetch[nPos.length-1].start(); Qy0w'L/@  
bf0,3~G,P  
o+&Om~W  
//等待子线程结束 Gmi? xGn  
//int count = 0; J)Y`G4l2@  
//是否结束while循环 e)n ,Y  
boolean breakWhile = false; y ;Cs#eo  
F`m}RL]g  
babL.Ua8o  
while(!bStop) :\P@c(c{^C  
{ 8 E\zjT!#\  
write_nPos(); PVp>L*|BZ;  
Utility.sleep(500); <+g77NL  
breakWhile = true; _*6]4\;  
tRJ5IX##L  
6vsA8u(|V#  
for(int i=0;i<nStartPos.length;i++) eZAMV/]jH  
{ '0+~]4&}q  
if(!fileSplitterFetch.bDownOver) pQBn8H|Y  
{ #| _VN %!  
breakWhile = false; m..ajYSQ  
break; &{.IUg  
} Z8ea)_ {#  
} G|f9l?p  
if(breakWhile) cVW7I  
break; BYXc 'K  
:vb5J33U  
wDh]vH[  
//count++; TPJF?.le '  
//if(count>4) nK :YbLdK,  
// siteStop(); ah:["< z<  
} b(GV4%  
dT*Yv`h  
H5x7)1Ir|  
System.err.println("文件下载结束!"); H?];8wq$G  
} d,Aa8I  
catch(Exception e){e.printStackTrace ();} ]|tg`*l!>  
} }x`Cnn  
"ktuq\a@  
h'-4nu;*  
//获得文件长度 8C@u+tx  
public long getFileSize() / S]RP>cQ  
{ ;7z6B|8  
int nFileLength = -1; ?'TK~,dG/  
try{ isL zgN%  
URL url = new URL(siteInfoBean.getSSiteURL()); q7Hf7^a  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); _x<NGIz  
httpConnection.setRequestProperty("User-Agent","NetFox"); g77M5(ME  
49Jnp>h  
= 0d|F 8  
int responseCode=httpConnection.getResponseCode(); n8<?<-2  
if(responseCode>=400) NS z }  
{ iibG$?(  
processErrorCode(responseCode); cDY)QUmi  
return -2; //-2 represent access is error H9(?yI@Zr#  
} EcB !bf  
>;I8w(  
X?'cl]1?  
String sHeader; +_7a/3kh  
:,0(aB  
~r.R|f]IQ  
for(int i=1;;i++) (L*GU7m;  
{ jXE:aWQht  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); B>L7UQ6_[  
//Utility.log(in.readLine()); gUru=p  
sHeader=httpConnection.getHeaderFieldKey(i); "5V;~}=S  
if(sHeader!=null) 60!%^O =  
{ _eiqs  
if(sHeader.equals("Content-Length")) i7.8H*z'  
{ (NvjX})eh  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); T"z<D+ pN  
break; Jr !BDg  
} tdH[e0x B  
} gPKf8{#%e  
else r& a[ ?  
break; G(a5@9F  
} RhE~Rwbx  
} [j0[c9.p [  
catch(IOException e){e.printStackTrace ();} +=8wZ]  
catch(Exception e){e.printStackTrace ();} mF;mJq<d  
h+1|.d  
skcyLIb  
Utility.log(nFileLength); `MSig)V  
cuQ!"iH  
@v lP)"  
return nFileLength; 5j`xSG  
} WY!\^| ,  
g{yw&q[B=  
5)%ahmY  
//保存下载信息(文件指针位置) $v@$C4  
private void write_nPos() 7{F\b  
{ R!j#  
try{ OZxJDg  
output = new DataOutputStream(new FileOutputStream(tmpFile)); @.W;3|~qc  
output.writeInt(nStartPos.length); q~R8<G%YK  
for(int i=0;i<nStartPos.length;i++) OS,!`8cw  
{ vdq=F|&  
// output.writeLong(nPos); \l:R]:w;ZI  
output.writeLong(fileSplitterFetch.nStartPos); <==uK>pET  
output.writeLong(fileSplitterFetch.nEndPos); :'DyZy2Fd  
} {}YA7M:L  
output.close(); Da(k>vR@4  
} %VO+\L8Fs  
catch(IOException e){e.printStackTrace ();} 'Bue*  
catch(Exception e){e.printStackTrace ();} h:8P9WhWF  
} +06{5-,  
<YU?1y?V  
^L2d%d\5  
//读取保存的下载信息(文件指针位置) Hx gC*-A$/  
private void read_nPos() s6|'s<x"j  
{  :RnUNz  
try{ {6ZSf[Y6B  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); fY00  
int nCount = input.readInt(); Km(i}:6"  
nStartPos = new long[nCount]; ST?{H SCz  
nEndPos = new long[nCount]; "] V\Y!  
for(int i=0;i<nStartPos.length;i++) A2 + %  
{ l}uZxKuYx  
nStartPos = input.readLong(); oK\zyNK  
nEndPos = input.readLong(); hU$o^ICH  
} |0i{z(B  
input.close(); [MpWvLP"x  
} 7 XxZF43  
catch(IOException e){e.printStackTrace ();} i=xh;yb|  
catch(Exception e){e.printStackTrace ();} :01d9|#  
} ;mU;+~YE  
EVqW(|Xg  
h< r(:.%!}  
private void processErrorCode(int nErrorCode) A'jvm@DvQI  
{ iM<$ n2t  
System.err.println("Error Code : " + nErrorCode); B5z'Tq1  
} ?sk>Mzr  
f`hZb  
=VD],R)  
//停止文件下载 >_2~uF@pb  
public void siteStop() ;TJpD0  
{ n*7^lAa2  
bStop = true; +c~&o83[  
for(int i=0;i<nStartPos.length;i++) ]:gW+6w"C  
fileSplitterFetch.splitterStop(); Ok_}d&A  
w#b@6d  
w,p'$WC*  
} B.; qvuM~  
} H'k}/<%Q  
//负责部分文件的抓取 \n[kzi7  
**FileSplitterFetch.java VCWW(Y1Fd  
*/ I<#X#_YP  
package NetFox; $+Ze"E  
Lk !)G'42  
-V}oFxk]q  
import java.io.*; nFQuoU]ux  
import java.net.*; JVIFpN"`  
DquL r+s~  
G(7%*@SX  
public class FileSplitterFetch extends Thread { i O$87!  
tB4mhX|\  
$P{`-Y }a  
String sURL; //File URL "-=fi 'D  
long nStartPos; //File Snippet Start Position =Dq&lm,n  
long nEndPos; //File Snippet End Position _qa]T'8  
int nThreadID; //Thread's ID q!c=f!U?\l  
boolean bDownOver = false; //Downing is over zGtJ@HbB  
boolean bStop = false; //Stop identical _Tj&gyS  
FileAccessI fileAccessI = null; //File Access interface 6M >@DRZ'|  
4Fft[S(  
]Ucw&B* @  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException CGi;M=xr  
{ v@=qVwX  
this.sURL = sURL; @-sWXz*W  
this.nStartPos = nStart; ,>-jZtm  
this.nEndPos = nEnd; !h.hJt  
nThreadID = id; p^8a<e?f~f  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 9O 'j+?(`@  
}  8oJl ]  
[#Qf#T%5h  
vaB ql(?'2  
public void run() 4 . 7X*1  
{ F@?-^ E@  
while(nStartPos < nEndPos && !bStop) inaO{ny y  
{ S"&Gutu3o  
"J"=<_?  
R,BJr y  
try{ Z[nHo'  
URL url = new URL(sURL); $U_(e:m}f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); (I$%6JO:  
httpConnection.setRequestProperty("User-Agent","NetFox"); yUnV%@.  
String sProperty = "bytes="+nStartPos+"-"; 7W)W9=&BT  
httpConnection.setRequestProperty("RANGE",sProperty); dx@dnWRT,  
Utility.log(sProperty); q}Q G<%VR  
G!Brt&_'  
3Q$ 4`p;  
InputStream input = httpConnection.getInputStream(); ;5ki$)v"  
//logResponseHead(httpConnection); =Ydrct  
>=0]7k;  
T_D3WHp  
byte[] b = new byte[1024]; gxl7j Y  
int nRead; _RaE: )  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) c-k3<|H`  
{ ;}E}N:A  
nStartPos += fileAccessI.write(b,0,nRead); un 5r9  
//if(nThreadID == 1) A`uHZCwJ5  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); r &.~ {  
} JN/=x2n.  
UfX~GC;B  
zcP=+Y)YA  
Utility.log("Thread " + nThreadID + " is over!"); c]u ieig0~  
bDownOver = true; tpGT~Y(  
//nPos = fileAccessI.write (b,0,nRead); ye.6tlW  
} oks;G([  
catch(Exception e){e.printStackTrace ();} @%,~5{Ir  
} on 7 n4  
} v":q_w<k  
:6Nb,Hh~  
1%v6d !  
//打印回应的头信息 |<u+Xi ~  
public void logResponseHead(HttpURLConnection con) %'1iT!g8  
{ KVOV<uDCj  
for(int i=1;;i++) m#UQ,EM  
{ Pdf-2 Tx  
String header=con.getHeaderFieldKey(i); ~LuGfPO^  
if(header!=null) 6=/sEzS'  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); xS1|t};  
Utility.log(header+" : "+con.getHeaderField(header)); v7"VH90`!  
else 56)!&MF  
break; +E</A:|}S  
} *V kaFQZ$,  
} Ye3o}G9z  
v/ N[)<  
K80f_ iT 5  
public void splitterStop() zu1"`K3b  
{ '6M6e(  
bStop = true; 486\a  
} X\m\yv}}  
/F;2wT;  
&ww-t..  
} xfeED^?  
VFf;|PHS  
Q2 !GWz$  
/* f5*qlQJFz\  
**FileAccess.java ZR\N~.  
*//文件访问(定位,写) C7dq=(p&  
package NetFox; Q#3}AO  
import java.io.*; @4y?XL(n  
4MPy}yT*  
WOn<;'}M&  
public class FileAccessI implements Serializable{ G[ U5R?/  
$l*?Ce:  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 )8C`EPe  
RandomAccessFile oSavedFile; m538p.(LIR  
long nPos; I$.lFQ%(  
GKFRZWXdT  
7K.75%}  
public FileAccessI() throws IOException nms[No?  
{ nod&^%O"  
this("",0); rNk'W,FU  
} #r#[&b  
]jD\4\M}  
/O:4u_  
public FileAccessI(String sName,long nPos) throws IOException @ ;!IPiU  
{ R%szN.cI  
oSavedFile = new RandomAccessFile(sName,"rw");  oYN"L  
this.nPos = nPos; _\4#I(  
oSavedFile.seek(nPos); :2KHiT5  
} =H)]HxEEM  
d'96$e o~  
[QxP9EC  
public synchronized int write(byte[] b,int nStart,int nLen) #A5X ,-4G  
{ UE^o}Eyg  
int n = -1; =Q<VU/  
try{ aM $2lR])J  
oSavedFile.write(b,nStart,nLen); ')v,<{  
n = nLen; H[hJUR+#  
} {`D]%eRO  
catch(IOException e) ~Y`ys[Z m  
{ Ibz9j uY  
e.printStackTrace (); yo[Sh6r/9b  
} |^-D&C(Eu  
7nT|yL?  
`+n0a@BVB  
return n; &j:e<{@  
} .L^*9Y0)  
WkiT,(i  
6agq^wI  
} 6#Z] yk+p  
 lPZ>#  
FQ4R>@@5  
/* 26/<\{q~  
**SiteInfoBean.java a"-uJn  
*/ `"65 _?B i  
package NetFox; Z5v_- +K  
r\"R?P$y|  
b[:,p?:@  
public class SiteInfoBean { %JBLp xnq  
ta{24{?M\  
eOb--@~8  
private String sSiteURL; //Site's URL rY(7IX  
private String sFilePath; //Saved File's Path ~T;:Tg*  
private String sFileName; //Saved File's Name PR"x&JG@  
private int nSplitter; //Count of Splited Downloading File fof}I:vO  
Y#c439&  
MtL<)?HQ  
public SiteInfoBean() %j^QK>%  
{//nSplitter的缺省值为5 @K!JE w\  
//default value of nSplitter is 5 pG"wQ  
this("","","",5); nT> v  
} ke2dQ^kc4  
9xbT?$^  
C"kfxpCi  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) A4,%l\di<  
{ KWo Ps%G  
sSiteURL= sURL; R{c~jjd  
sFilePath = sPath; =l:V9u-I^  
sFileName = sName; ?Ojv<L-f.:  
this.nSplitter = nSpiltter; G%HG6  
}kt%dDU  
P@@MQ[u?!.  
} *jhgCm  
'nPI zK<v  
=-Hhm($n  
public String getSSiteURL() .I~:j`K6  
{ q>(?Z#sB  
return sSiteURL; GcN}I=4|  
} Lx>[`QT  
4AEw[(t  
'GezIIaH  
public void setSSiteURL(String value) ,oH\rrglf  
{ d,?D '/  
sSiteURL = value; )A*53>JV  
} c<Cf|W  
p^ (Z  
w#)u+^-  
public String getSFilePath() T(u; <}e@[  
{ +JYb)rn$^  
return sFilePath; tRI<K  
} /TsXm-g#  
lF64g  
Iq%<E:+GL  
public void setSFilePath(String value) $yi:0t8t  
{ G0!6rDu2,  
sFilePath = value; Jf4` 2KN\  
} q`PA~C];  
1|8Bv0-b  
b;D  
public String getSFileName() 7yu-xnt3s  
{ B?&0NpVD  
return sFileName; W#!AZ!  
} WYF8?1dt +  
FR6 W-L  
6IRRRtO(  
public void setSFileName(String value) p#qla'  
{ MS#"TG/)  
sFileName = value; A-1K TD  
} z&0[F`U  
&Ih }"  
<_8b AO8\  
public int getNSplitter() )SP"V~^Wn  
{ 'y!qrmMRr  
return nSplitter; 5|0/$ SWd*  
} 6p }a!  
+x{o  
> }f!. i  
public void setNSplitter(int nCount) H.|I|XRG/  
{ BegO\0%+  
nSplitter = nCount; MR,I`9Pe  
} NV?x<LNWd  
} e46`"}r  
|pZ7k#%  
]8wm1_qV  
/* PeIi@0vA  
**Utility.java Lk]|;F-2i  
*/ 9h+Hd&=  
package NetFox; ,j>FC j>  
@7"n X  
9=$ pV==  
public class Utility { JAKs [@:  
3mofp`e  
nygGI_[l  
public Utility() HD#>K 7  
{ ;39a`  
zd2_k 9  
0kCo0{+n  
} $k )K}U  
h/A\QW8Sd  
//线程睡眠 5Q%)|(U'  
public static void sleep(int nSecond) U"|1@W#  
{ =D0d+b6  
try{ M 2| k.  
Thread.sleep(nSecond); b=S"o )>  
} uSYI X  
catch(Exception e) Y*pXbztP  
{ V?*fl^f  
e.printStackTrace (); v+xrn z  
} $X;OK  
} vh&~Y].W Y  
KsTGae;ds  
//日志 q p}2  
public static void log(String sMsg) 72RTEGy  
{ h{o,*QL  
System.err.println(sMsg); `+(n+QS _  
} bxPa|s?  
{q$U\y%Rq  
w5y.kc;  
public static void log(int sMsg) e8):'Cb   
{ J V}7c$_  
System.err.println(sMsg); 8IL5 :7H8  
} %"c;kvw  
} Mu:zWLM*M  
?r(vXq\  
&S*{a  
/* |O)ZjLx  
**TestMethod.java B>'J5bZsw  
*/ mpD.x5jm<  
package NetFox; h`! 4`eI  
uL7}JQ,  
gA_oJW4_  
public class TestMethod { -">Tvi4  
g qORE/[  
dHOH]x  
public TestMethod() o$->|k  
{ ///xx/weblogic60b2_win.exe  8zRw\]?  
try{ 8?m=Vw<kIZ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); B!`.,3  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); B QUYT/$(  
SiteFileFetch fileFetch = new SiteFileFetch(bean); a'-xCV|^  
fileFetch.start(); r UZN$="N  
} #p;<X|Hc}8  
catch(Exception e){e.printStackTrace ();} 2=fLb7  
7}\AhQ, S  
[-#1;!k  
} OY|9V  
)40YA\V  
Ie Chz d  
public static void main(String[] args) ,1|=_M31  
{ i)cG  
new TestMethod(); VIGLl'8p  
} =&-.]| t  
} @o@SU"[?_  
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