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http断点续传简单实现(java)

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/* q*O KA5  
**SiteFileFetch.java Pa}vmn1$  
*/ g8Z14'Ke  
package NetFox; 4lA+V,#  
import java.io.*; o[#a}5Y  
import java.net.*; z"3c+?2  
(zBQ^97]  
={^#E?  
public class SiteFileFetch extends Thread { oK6lCGM5  
tOw 0(-:iq  
S2)S/ nf  
SiteInfoBean siteInfoBean = null; //文件信息Bean 5WT\0]RUa  
long[] nStartPos; //开始位置 &}O!l'  
long[] nEndPos; //结束位置 `?x$J 6p  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 dK: "  
long nFileLength; //文件长度 e`r;`a&  
boolean bFirst = true; //是否第一次取文件 s /M~RB!w  
boolean bStop = false; //停止标志 J~q+G  
File tmpFile; //文件下载的临时信息 kP$g l|  
DataOutputStream output; //输出到文件的输出流 37xxVbik  
YW<2:1A|  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) F6p1 VFs  
public SiteFileFetch(SiteInfoBean bean) throws IOException {%{GZ  
{ cAS_?"V a  
siteInfoBean = bean; J|-HZ-Wk|J  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); sFK<:ka  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); D OeKW  
if(tmpFile.exists ()) cqx1NWlY  
{ }=a4uCE  
bFirst = false; h>:RCpC  
read_nPos(); "zbE  
} {M/c!  
else E,7~kd~y`  
{ T;@>O^  
nStartPos = new long[bean.getNSplitter()]; ]'(7T#  
nEndPos = new long[bean.getNSplitter()]; rzDJH:W{2  
} 4&e@>  
|@.<} /  
BA,6f?ktXS  
Ib!rf:  
} RWFf-VA?  
7-I>5 3@  
VU9P\|c@<  
public void run() v\,%)Z/  
{ yipD5,TC  
//获得文件长度 z :v, Vu  
//分割文件 v Lv@Mo  
//实例FileSplitterFetch -G#k/Rz6  
//启动FileSplitterFetch线程 sG2 3[t8  
//等待子线程返回 5Q`n6x|  
try{ (JW?azU  
if(bFirst) N?0y<S ?!  
{ C+XZDY(=Z  
nFileLength = getFileSize(); D 'cY7P  
if(nFileLength == -1) RH]>>tJ^e  
{ nM-SDVFM  
System.err.println("File Length is not known!"); DWQQ615i  
} D^55:\4(  
else if(nFileLength == -2) a +yI2s4Z  
{ !m(L0YH  
System.err.println("File is not access!"); ;bZ*6-\!-  
} 1Uk~m  
else vN:[  
{ )C]&ui~1  
for(int i=0;i<nStartPos.length;i++) xY2_*#{.  
{ ROS"VV<  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); g ypq`F  
} ^alZ\!B8  
for(int i=0;i<nEndPos.length-1;i++) 2Fgt)`{!  
{ + <9 eN  
nEndPos = nStartPos[i+1]; ,$zlw\  
} BK9x`Oo2  
nEndPos[nEndPos.length-1] = nFileLength; '<< ~wt  
} Uy5!H1u  
} PMhhPw]  
1Dp @n  
L~y tAZ,  
//启动子线程 'h>5&=r  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; puN=OX}C  
for(int i=0;i<nStartPos.length;i++) M5WtGIV  
{ QhQ"OVFr#  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), 8`2<g0V2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), ,G|aLBn  
nStartPos,nEndPos,i); 6F.7Ws <  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); nDB 2>J  
fileSplitterFetch.start(); wZ8 MhE  
} kN |5 J  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), B36puz 0{  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); OP`Jc$| 6  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", ?%/u/*9rj  
nEndPos = " + nFileLength); 68<Z\WP  
// fileSplitterFetch[nPos.length-1].start(); ~X<cG=p~u  
o 7W Kh=  
q%k(M[  
//等待子线程结束 %m{.l4/!O  
//int count = 0; 1"&;1Ts  
//是否结束while循环 6$s0-{^  
boolean breakWhile = false; H9VXsFTW  
|\|)j>[i  
``|RO[+2  
while(!bStop) dM s||&|&  
{ ^qGA!_  
write_nPos(); X";Z Up  
Utility.sleep(500); 15KV} ){  
breakWhile = true; M&/aJRBS  
wK'!xH^  
OssR[$69  
for(int i=0;i<nStartPos.length;i++) TT2cOw  
{ D"XX920$~  
if(!fileSplitterFetch.bDownOver) \!JS7!+  
{ !\-4gr?`!  
breakWhile = false; KU|BT .o8  
break; "WbVCT'i  
} g(1B W#$  
} -}X?2Q  
if(breakWhile) G/z\^Q  
break; !3I(4?G,  
daB l%a=  
mPfUJ#rS  
//count++; 1%spzkE 3P  
//if(count>4) o9Txo (tYU  
// siteStop(); qwF*(pTHq  
} Z@,PZ   
WVWS7N\  
w^])(  
System.err.println("文件下载结束!"); qfG tUkSSb  
} QGr\I/Y  
catch(Exception e){e.printStackTrace ();} 3g0u#t{  
} }#OqU# q|  
o"#TZB+k  
}B=qH7u.K  
//获得文件长度 2:iYYRrg  
public long getFileSize() |ck ZyDA  
{ wD6!#t k  
int nFileLength = -1; |O(-CDQe  
try{ t1w2u.]  
URL url = new URL(siteInfoBean.getSSiteURL()); yS)- &t!;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w}j6 .r  
httpConnection.setRequestProperty("User-Agent","NetFox"); kOAY@a  
_}zo /kDA  
z$c&=Q  
int responseCode=httpConnection.getResponseCode(); gX$0[ sIS.  
if(responseCode>=400) qcTmsMpj  
{ c.(Ud`jc  
processErrorCode(responseCode); Zj1ZU[BEcL  
return -2; //-2 represent access is error J3~hzgY  
} f2 ydL/M,  
0L:V#y-*  
22GnbA7O  
String sHeader; =! N _^cb  
to&N22a$  
\5Vp6^  
for(int i=1;;i++) lk_s!<ni  
{ X'FEOF  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); .]j#y9>&w%  
//Utility.log(in.readLine()); `10X5V@hP  
sHeader=httpConnection.getHeaderFieldKey(i); E kBae=  
if(sHeader!=null) qRPc %"  
{ /&]-I$G@  
if(sHeader.equals("Content-Length")) >*`>0Q4y  
{ ?ds f@\  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 3>Q@r>c  
break; ADYx.8M|9i  
} jby~AJf %  
} /M^V 2=  
else 'Aj(i/CM  
break; [jl2\3*  
} X`yNR;>  
} .!JMPf"QEI  
catch(IOException e){e.printStackTrace ();} 3(!/["@7  
catch(Exception e){e.printStackTrace ();} IXZ(]&we  
Vk-W8[W 7  
~reQV6oQua  
Utility.log(nFileLength); -F"d0a,  
G{kj}>kS_  
uxa=KM1H  
return nFileLength; ,`<^F:xl  
} \|2t TvW,0  
8 7RHA $?  
 Y*@|My`  
//保存下载信息(文件指针位置) rIeM+h7Wn  
private void write_nPos() 61/)l0 <;  
{ Hp\Ddx >Jd  
try{ V@vhj R4r\  
output = new DataOutputStream(new FileOutputStream(tmpFile)); m[Z6VHn  
output.writeInt(nStartPos.length); uR#'lb`3  
for(int i=0;i<nStartPos.length;i++) IQ3n@  
{ .OmQ'  
// output.writeLong(nPos); ?k{|Lk  
output.writeLong(fileSplitterFetch.nStartPos); gyi)T?uS)  
output.writeLong(fileSplitterFetch.nEndPos); @Q;i.u{V  
} P*pbwV#|  
output.close(); r\(v+cd  
} S:ls[9G[3  
catch(IOException e){e.printStackTrace ();} 9i0M/vx  
catch(Exception e){e.printStackTrace ();} =op`fn%  
} tC&fA E:S  
u3]Uxy  
[{`)j  
//读取保存的下载信息(文件指针位置) p?Ed- S  
private void read_nPos() sFLcOPj-%  
{ Hqvc7-c6  
try{ >b>M Km>q  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); NEA_Plt  
int nCount = input.readInt(); 79D=d'e A  
nStartPos = new long[nCount]; E{uf\Fc   
nEndPos = new long[nCount]; !w q4EV  
for(int i=0;i<nStartPos.length;i++) i90}Xyt  
{ Q[M (Wqg  
nStartPos = input.readLong(); (lb6]MtTHY  
nEndPos = input.readLong(); R6`*4z S  
} 0$tjNy e  
input.close(); Mx8Gu^FW.d  
} On=u#DxQ  
catch(IOException e){e.printStackTrace ();} DU;[btK>  
catch(Exception e){e.printStackTrace ();} h$70H^r  
} 9b1?W?"  
<B!'3C(P  
##H;Yb  
private void processErrorCode(int nErrorCode) =HVfJ"vK  
{ R|iEvt  
System.err.println("Error Code : " + nErrorCode); &K>cW$h=a  
} +UzXN$73  
-'6<   
&i5:)d]L  
//停止文件下载 ~n WsP}`n  
public void siteStop() || [89G  
{ %JQ~!3  
bStop = true; 6/| 0+G^  
for(int i=0;i<nStartPos.length;i++) 6O9iEc,HM  
fileSplitterFetch.splitterStop(); z!$gVWG  
mj@31YW  
XYjcJ  
} 4r\*@rq  
} ~\$=w10  
//负责部分文件的抓取 Jen%}\  
**FileSplitterFetch.java PWvSbn6  
*/ D9.`hs0  
package NetFox; QC{u|  
mzGjRl=O  
1?(cmXj  
import java.io.*; *(G&B\  
import java.net.*; 4QE=f(u;h  
r} Lb3`'  
/HkFlfPd  
public class FileSplitterFetch extends Thread { bni) Qw  
Pp+~Cir  
g<$. - g  
String sURL; //File URL vt.P*Z5  
long nStartPos; //File Snippet Start Position }taLk@T  
long nEndPos; //File Snippet End Position Q"%S~&#'  
int nThreadID; //Thread's ID qe$33f*  
boolean bDownOver = false; //Downing is over j$Nf%V 6Y  
boolean bStop = false; //Stop identical ~wOTjz  
FileAccessI fileAccessI = null; //File Access interface MTb,Kmw<(  
1AF%-<`?s  
d ",(a Z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException d ;^  
{ n!G.At'JP  
this.sURL = sURL; |O-`5_z$r  
this.nStartPos = nStart; w9f _b3  
this.nEndPos = nEnd; hGI+:Js6  
nThreadID = id; yHNuU)Ft  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7X}TB\N1  
} ]]TqP{H  
wiJRCH  
$W&:(&  
public void run() vT c7an6fy  
{ YLOwQj'  
while(nStartPos < nEndPos && !bStop) l4vTU=  
{ 4(=kE>n}  
oQT2S>cm^  
E1  |<Pt  
try{ "_< 9PM1t  
URL url = new URL(sURL); X*F_<0RC1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); cJDd0(tD!  
httpConnection.setRequestProperty("User-Agent","NetFox"); *}cSE|S%  
String sProperty = "bytes="+nStartPos+"-"; 7+nm31,<O  
httpConnection.setRequestProperty("RANGE",sProperty); >{5 p0  
Utility.log(sProperty); \\:|Odd  
+;Cr];b3  
Icx7.Y  
InputStream input = httpConnection.getInputStream(); V}" g~=  
//logResponseHead(httpConnection); ;+U<bqL6  
0{+.H_f`  
M:|8]y@  
byte[] b = new byte[1024]; /=)L_  
int nRead; gKo%(6{n~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) a460|w6  
{ 7Xg?U'X  
nStartPos += fileAccessI.write(b,0,nRead); WC*=rWRxF  
//if(nThreadID == 1) rrqQCn9  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Wd8R u/  
} Gb2L }  
6L9, 'Bg  
*k [J6  
Utility.log("Thread " + nThreadID + " is over!"); yZCX S  
bDownOver = true; &Z;_TN9[  
//nPos = fileAccessI.write (b,0,nRead); T95t"g?p  
} W .I\J<=V  
catch(Exception e){e.printStackTrace ();} dNiH|-$an  
} |3shc,7  
} bgF^(T35  
BRS#Fl:  
O_;Dk W  
//打印回应的头信息 SZhOm  
public void logResponseHead(HttpURLConnection con) h Dk)Qg  
{ !GwL,)0@^  
for(int i=1;;i++) -Z0+oU(?YE  
{ L',mKOej  
String header=con.getHeaderFieldKey(i); *?t%0){  
if(header!=null) V'DA[{\*  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); UZ2TqR  
Utility.log(header+" : "+con.getHeaderField(header)); M Hi8E9_O  
else )Si2 u5  
break; YKZa$@fA?  
} @1-F^G%p8  
} z6*<V5<7  
3j Z6kfj  
`P}9i@C  
public void splitterStop() $}GTG'*.  
{ F;q#&  
bStop = true; Kibr ]w  
} a5jL7a?6]  
J00VTb`  
o!c] (  
}  ?K_ '@  
*\G)z|^yx  
0bS|fMgc  
/*  :A1:  
**FileAccess.java @-&MA)SN  
*//文件访问(定位,写) T-_"|-k}P%  
package NetFox; =(HeF.!  
import java.io.*; c>:R3^\lwx  
bBc[bc>R  
`aC){&AP(  
public class FileAccessI implements Serializable{ . pzC5Ah  
z (?=Iv3  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 m ci/'b Xt  
RandomAccessFile oSavedFile; O%8EZyu  
long nPos; "N?+VkZEv  
u #w29Pm  
(kv?33  
public FileAccessI() throws IOException _)T5lEFl=  
{ J aTp} #  
this("",0); S! v(+|  
} <{5EdX  
'Ft0Ry<OL  
q 11IkDa  
public FileAccessI(String sName,long nPos) throws IOException )3Z ^h<"j  
{ HlvuW(,x=  
oSavedFile = new RandomAccessFile(sName,"rw"); RTh`ENCKR  
this.nPos = nPos; <r#eL39I  
oSavedFile.seek(nPos); V w||!d  
} m,UGWR  
:a ->0 l  
6 5N~0t  
public synchronized int write(byte[] b,int nStart,int nLen) #X 52/8G  
{ j)C,%Ol  
int n = -1; H,nec<Jp  
try{ o%9*B%HO/  
oSavedFile.write(b,nStart,nLen); d?`ny#,GB  
n = nLen; aE;le{|!({  
} scLn=  
catch(IOException e) fC,:{}  
{ t3(]YgF  
e.printStackTrace (); J &pO%Q=b  
} FCi U  
[I!6PGx  
2EZb )&Q  
return n; Y2o?gug  
} $6OkIP.  
WmY``  
ojyIQk+  
} S"wR%\NIp  
7(5xL T$  
pn.wud}R  
/* a,2'+Tlo  
**SiteInfoBean.java 8V^oP] Y  
*/ =6"2UC&  
package NetFox; X/iT)R]b  
EQ'V{PIfj  
?7<JQh)"e  
public class SiteInfoBean { Zjbc3 M5  
3)\8%Ox  
MrZh09y  
private String sSiteURL; //Site's URL t2,A@2DU 2  
private String sFilePath; //Saved File's Path UfN&v >8f  
private String sFileName; //Saved File's Name KMI_zhyB  
private int nSplitter; //Count of Splited Downloading File 0"CG7Vg,zh  
^*P%=>zO  
&|f@$ff  
public SiteInfoBean() 8GvJ0Jq}U  
{//nSplitter的缺省值为5 rM'=_nmi  
//default value of nSplitter is 5 xx[9~z=d  
this("","","",5); ZI=%JU(  
} sCR67/  
=c/wplv*  
}ZYv~E'  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) fQ#l3@in  
{ Z ?wU  
sSiteURL= sURL; e,t(q(L  
sFilePath = sPath; (M*FIX  
sFileName = sName; U}[I   
this.nSplitter = nSpiltter; 5$V_Hj  
^h69Kr#d4  
0NS<?p~_S  
} bbrXgQ`s+w  
l c+g&f  
9 FB19  
public String getSSiteURL() -r-k_6QP  
{ ^J$2?!~  
return sSiteURL; R8ZK]5{o  
} spt6]"Ni  
KXx32 b,~  
0g+'/+Ho 4  
public void setSSiteURL(String value) q@[Qj Gj@  
{ Y;?{|  
sSiteURL = value; _lamn }(x0  
} V5UF3'3;}  
["h5!vj  
9I&xfvD,  
public String getSFilePath() nih0t^m'  
{ 19w*!FGX  
return sFilePath; 7Zlw^'q$:L  
} wK?vPS  
Tj:B!>>  
 R}O_[  
public void setSFilePath(String value) $<}$DH_Y  
{ tfj:@Z5&$C  
sFilePath = value; P-?0zF/T$  
} &J+CSv,39  
wne,e's}   
LDPUD'  
public String getSFileName() Xu%'Z".>:  
{ wOU_*uY@6'  
return sFileName; ML|FQ  
} f&Gt|  
}H^+A77v  
KV(Q;~8"X  
public void setSFileName(String value) >CHrg]9  
{ lhy*h_>  
sFileName = value; ?l9XAW t\  
} D]zwl@sRX:  
nAv#?1cjz  
?8'*,bK  
public int getNSplitter() 'uBu6G  
{ 4y|BOVl  
return nSplitter; $g> IyT[  
} aAD^^l#  
]n6#VTz*  
]s<[D$ <,  
public void setNSplitter(int nCount) t'n pG}`tE  
{ -XB/lnG  
nSplitter = nCount; A^USBv+9`  
} JMC. w!  
} fp`;U_-&0  
;ub;l h3  
+S o4rA*9  
/* Ayxkv)%:@)  
**Utility.java uXn1 'K<'2  
*/ uvkz'R=  
package NetFox; b3=rG(0f  
8A##\j )  
vS;RJg=  
public class Utility { %)1y AdG 8  
CsGx@\jN  
v[1aW v:  
public Utility() Kp%2k^U  
{ G<65H+)M\  
>qnko9V  
wW>A_{Y  
} d; boIP`M;  
s6 uG`F"  
//线程睡眠 ztcp/1jIvS  
public static void sleep(int nSecond) jeoz* Dz  
{ (C\]-E>  
try{ f6hnTbJ  
Thread.sleep(nSecond); +$ 'Zf0U  
} &u$Q4  
catch(Exception e) E(>=rD/+  
{ P3x8UR=fS  
e.printStackTrace (); N G+GEqx  
} "L IF.)  
} 9ijfRqI=x  
3l rT3a3vV  
//日志 11 Q1AN  
public static void log(String sMsg) Ag-(5:  
{ 8\&X2[oAD  
System.err.println(sMsg); fK>L!=Q  
} 1m4$p2j  
~!B\(@GU  
'OITI TM  
public static void log(int sMsg)  -*1d!  
{ f,U.7E  
System.err.println(sMsg); UXJ eAE-  
} &* M!lxDN  
} "q3ZWNS'w  
K@ I 9^b  
(S>C#A=E\  
/* ,0 M_ Bk"  
**TestMethod.java V(H1q`ao9  
*/ o_izl \  
package NetFox; 03$mYS_?  
R`NYEptJ  
KLST\ Ln:  
public class TestMethod { B6MB48#0gs  
T6\[iJI|  
(nQ^  
public TestMethod() p $S*dr  
{ ///xx/weblogic60b2_win.exe ;AG8C#_  
try{ .]8ZwAs=&  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); d[iQ` YW5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); bV^rsJm  
SiteFileFetch fileFetch = new SiteFileFetch(bean); qU \w=  
fileFetch.start(); Q *D;U[  
} qqjwJ!@P  
catch(Exception e){e.printStackTrace ();} `+]Qz =}  
(p"%O  
4>wP7`/+y  
} R$R *'l  
!z\h| wU+  
\1k79c  
public static void main(String[] args) yuh *  
{ <$D`Z-6  
new TestMethod(); 8?xE6  
} )W^F2-{  
} ju8> :y8  
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