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http断点续传简单实现(java)

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/* tTt}=hQpgX  
**SiteFileFetch.java j~9![s!  
*/ QV#HN"F/K  
package NetFox; uFvR(LDb&g  
import java.io.*; =#{q#COK$  
import java.net.*; UZ:z|a3  
i0?/\@gd  
E429<LQI/  
public class SiteFileFetch extends Thread { 3_{rXtT)'  
usi3z9P>n  
#nj;F'O](  
SiteInfoBean siteInfoBean = null; //文件信息Bean z\WyL;  
long[] nStartPos; //开始位置 *d 4A3|  
long[] nEndPos; //结束位置 lgb q^d  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 5+(Cp3  
long nFileLength; //文件长度 {aU|BdATI  
boolean bFirst = true; //是否第一次取文件 {817Svp@  
boolean bStop = false; //停止标志 A9GSeW<  
File tmpFile; //文件下载的临时信息 :j32 :/u  
DataOutputStream output; //输出到文件的输出流 f]Rh<N$  
>LVGNicQ  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 3A! |M5  
public SiteFileFetch(SiteInfoBean bean) throws IOException xxC2 h3  
{ 19Mu}.+;  
siteInfoBean = bean; . lSoC`HE  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); YYe=E,q  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -V'Y^Df  
if(tmpFile.exists ()) |#(y?! A^  
{ cCG!X%9  
bFirst = false; N{a=CaYi+  
read_nPos(); +7y#c20  
} fzN?X=  
else O6\c1ha  
{ &hM7y7  
nStartPos = new long[bean.getNSplitter()]; +Je%8jH  
nEndPos = new long[bean.getNSplitter()]; *qr>x8OGp  
} m,rkKhXP  
L3*HgkQQ  
iBY16_q  
{]4Zpev  
} .k,,PuP  
B~YOU 3  
~bw=;xF{3  
public void run() `2M*?.vk  
{ 'sa>G  
//获得文件长度 >h$Q%w{V  
//分割文件 mPo.Z"uy7  
//实例FileSplitterFetch 7T(&DOGZ  
//启动FileSplitterFetch线程 @E"lN  
//等待子线程返回 dleCh+ny?  
try{ ^SIA%S3  
if(bFirst) )E^Pn|H  
{ G4\|bwh  
nFileLength = getFileSize();  y&wo"';  
if(nFileLength == -1) d@ ] N  
{ c^z) [  
System.err.println("File Length is not known!"); |z0% q2(  
} ^W~8)Rbf  
else if(nFileLength == -2) rrG}; A  
{ CF : !  
System.err.println("File is not access!"); -U|Z9sia  
} xZVZYvC,t  
else 7zowvE?#  
{ u>*qDr* d  
for(int i=0;i<nStartPos.length;i++) mA^3?y j  
{ #S[Y}-]T  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); N7_(,Gu*R  
} @h/-P'Lc=7  
for(int i=0;i<nEndPos.length-1;i++) p!\ GJ a",  
{ B) dG:~  
nEndPos = nStartPos[i+1]; BQB<+o'  
} _\{/#J;lN  
nEndPos[nEndPos.length-1] = nFileLength; 7vc4 JO]  
} #oN}DP  
} i9T<(sdK+  
 6NSSuK3  
u~~ ~@p  
//启动子线程 F6"s&3D{  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; 9~y:K$NO  
for(int i=0;i<nStartPos.length;i++) }]^/`n  
{ &}\{qFD;  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), SH O&:2  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), CY$ 1;/  
nStartPos,nEndPos,i); Q% ^_<u  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); R 83PHM  
fileSplitterFetch.start(); x{/-&`F  
} bH!_0+$P  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), -z%->OUu  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); Bm<tCN-4  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", \S{ihS@J  
nEndPos = " + nFileLength); ,bP8"|e  
// fileSplitterFetch[nPos.length-1].start(); {XwDvLZ  
({D>(xN   
tvJl&{-OX  
//等待子线程结束 )19#g1rn5  
//int count = 0; LLbI}:  
//是否结束while循环 D}U gC\u  
boolean breakWhile = false; 3sDyB-\&  
nGur2}>n  
AoK;6je`K^  
while(!bStop) P ,rLyx   
{ dux_v"Xl  
write_nPos(); ZP-9KA$"  
Utility.sleep(500); ]cW Q9  
breakWhile = true; D%6}x^`Qk  
(!Xb8rV0_  
VFm)!'=I  
for(int i=0;i<nStartPos.length;i++) K cW 5  
{ qac:"z'9  
if(!fileSplitterFetch.bDownOver) r$Ik* R  
{ _qh \  
breakWhile = false; <N3~X,ch  
break; V}Oz!  O  
} Cu<' b'%;  
} ^==Tv+T9U  
if(breakWhile) v?n# C  
break; J|HV8  
+U?73cYN  
a.ijc>K  
//count++; 6="o&!  
//if(count>4) =\\rk,F  
// siteStop(); Cv p#=x0  
} 9NZq k  
z]=Ks_7  
?9?o8!  
System.err.println("文件下载结束!"); mxe\+j#  
} A5[kYD,_  
catch(Exception e){e.printStackTrace ();} Yk*_u}?#  
} z`D|O|#q  
KvI/!hl\  
<,H/7Ba  
//获得文件长度 YfNN&G4_  
public long getFileSize() ]{I>HA5[  
{ c)q=il7ef  
int nFileLength = -1; Z+4Mo*#  
try{ TPY&O{ q  
URL url = new URL(siteInfoBean.getSSiteURL()); w2^s}NO  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ^{NN-  
httpConnection.setRequestProperty("User-Agent","NetFox"); B =DV!oUg  
]eTp?q%0  
O.aAa5^uh  
int responseCode=httpConnection.getResponseCode(); `[ZA#8Ma  
if(responseCode>=400) h-o;vC9fC  
{ :JXcs39  
processErrorCode(responseCode); TQvjU!>  
return -2; //-2 represent access is error !u`f?=s;  
} f,BJb+0  
#X6=`Xe#  
K5(T7S  
String sHeader; 7mb5z/N  
IEfm>N-]  
XD[9wd5w8  
for(int i=1;;i++) 5Iv"  
{ ]0{,P !  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); =E~_F>SD  
//Utility.log(in.readLine()); *6v5JH&K  
sHeader=httpConnection.getHeaderFieldKey(i); w}29#F\]R  
if(sHeader!=null) \`8F.oZ^)  
{ {4%ddJn[.)  
if(sHeader.equals("Content-Length")) E>"SC\#7  
{ "`w*-O  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ubsx NCqD  
break; = @FT$GQ  
} u4[JDB7tH  
} XW{cC`&  
else #O'g*]j  
break; YKx+z[A/p  
} \;"S>dg  
} aecvz0}@R  
catch(IOException e){e.printStackTrace ();} EE qlsH  
catch(Exception e){e.printStackTrace ();} 0BOL0<Wq  
t V7{j'If  
cr^R9dv  
Utility.log(nFileLength); "7?xaGh8  
zS?DXE  
5)w;0{X!P  
return nFileLength; @*$"6!3s5  
} aCBq}Xcn  
0s.4]Zg>5  
m# ^).+  
//保存下载信息(文件指针位置) ldG$hk'  
private void write_nPos() w *o _s  
{ t"6u  
try{ AP?m,nd6  
output = new DataOutputStream(new FileOutputStream(tmpFile)); ?W&ajH_T  
output.writeInt(nStartPos.length); \i)@"}  
for(int i=0;i<nStartPos.length;i++) <(us(zbk]  
{ \/r]Ra  
// output.writeLong(nPos); =e6!U5 f  
output.writeLong(fileSplitterFetch.nStartPos); A}1:fw\Fn3  
output.writeLong(fileSplitterFetch.nEndPos); (. ,{x)H  
} [bN_0T.YI  
output.close(); <H1e+l{8$  
} V("T9g  
catch(IOException e){e.printStackTrace ();} N/E=-&E8  
catch(Exception e){e.printStackTrace ();} Ge76/T%{Q  
} "(:8 $Fb  
wee5Nirw6  
b/=>'2f  
//读取保存的下载信息(文件指针位置) ?;go5f+X  
private void read_nPos() 0LP>3"Sm  
{ r \} O{ZO  
try{ /(i~Hpp  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); M!\6Fl{ b  
int nCount = input.readInt(); J!zL)u|  
nStartPos = new long[nCount]; o1Wf#Zq   
nEndPos = new long[nCount]; G:MQ_tfr&  
for(int i=0;i<nStartPos.length;i++) |:d_IB@  
{ N&u(9Fxn  
nStartPos = input.readLong(); /IC]}0kkp  
nEndPos = input.readLong(); <|:$_&(  
} `iwGPG!  
input.close(); 3d_g@x#9  
} ) KYU[  
catch(IOException e){e.printStackTrace ();} 6x8lnXtA  
catch(Exception e){e.printStackTrace ();} qp]s VY  
} 4WQ 96|F  
Uz7V2r%]  
#YLI"/Kn  
private void processErrorCode(int nErrorCode) x}N1Wl=8g  
{ & )EL%o5  
System.err.println("Error Code : " + nErrorCode); a+n?y)u  
} OEHw%  
kgRgHkAH~  
B5va4@  
//停止文件下载 cLMFC1=b  
public void siteStop() t%Y}JKLR  
{ .~4DlT  
bStop = true; QST-!`]v  
for(int i=0;i<nStartPos.length;i++) SwhArvS  
fileSplitterFetch.splitterStop(); e\]CZ5hs3  
1ka58_^  
et6@);F  
} _[J>GfQd  
} /6p7 k  
//负责部分文件的抓取 2>inyn)S  
**FileSplitterFetch.java <U""CAE  
*/ pKk{Q0Rt  
package NetFox; Vj_z"t7q  
T'VKZ5W  
TK%MVLTK  
import java.io.*; 5U(ry6fI=  
import java.net.*; A#w*r-P  
O,7*dniH  
H=_k|#/  
public class FileSplitterFetch extends Thread { Bj\oo+L/  
/f,*|  
qBWt(jY  
String sURL; //File URL ;<|m0>X  
long nStartPos; //File Snippet Start Position /k^O1+]H  
long nEndPos; //File Snippet End Position Y; q['h  
int nThreadID; //Thread's ID $C6O<A  
boolean bDownOver = false; //Downing is over ]N1gzHaS  
boolean bStop = false; //Stop identical |_wbxdq  
FileAccessI fileAccessI = null; //File Access interface `"j_]  
Iy {&T#e"  
(t-JGye>  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @!Q\| <  
{ n6 AP6PK7  
this.sURL = sURL; },tn  
this.nStartPos = nStart; LgoUD*MbQ  
this.nEndPos = nEnd; y Ide]  
nThreadID = id; {@<EVw  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 jX{t/8v/s4  
}  .tRWL!  
JUC62s#_z  
;=?KQq f  
public void run() Kyq/o-  
{ n4Eqm33  
while(nStartPos < nEndPos && !bStop) z8n]6FDiE  
{ 4w0Y(y  
P/hIJV[  
\BxE0GGky  
try{ v8o{3wJ  
URL url = new URL(sURL); (]p,Z <f  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); ,;-55|o\V  
httpConnection.setRequestProperty("User-Agent","NetFox"); ]abox%U=%  
String sProperty = "bytes="+nStartPos+"-"; _l!TcH+e  
httpConnection.setRequestProperty("RANGE",sProperty); +;wu_CQu  
Utility.log(sProperty); <Q? X'.  
<YBA 7i  
*ZA.O  
InputStream input = httpConnection.getInputStream(); bcZ s+FOPd  
//logResponseHead(httpConnection); A{b?ZT~2]  
Dz>v;%$S-  
[1gWc`#  
byte[] b = new byte[1024]; S,TK;g  
int nRead; .jC-&(R +  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ^ G(GjW8  
{ H0\5a|X-  
nStartPos += fileAccessI.write(b,0,nRead); WD,iY_'7u^  
//if(nThreadID == 1) gsp|?) ]x  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); !<xeAo%8  
} 6tg0=_c  
4zM$I  
rZv5>aEI  
Utility.log("Thread " + nThreadID + " is over!"); cA{zyq26  
bDownOver = true; L|[ 0&u!  
//nPos = fileAccessI.write (b,0,nRead); Gdf*x<T1  
} %rZJ#p[e)=  
catch(Exception e){e.printStackTrace ();} l~V^  
} F2$Z4%x#  
} bC@9 */i  
' |>  
?1u2P$d  
//打印回应的头信息 ]MXeWS(  
public void logResponseHead(HttpURLConnection con) Z6I^HG{:  
{ ~&Gw[Nd1  
for(int i=1;;i++) wx|eO[14  
{ Fn~?YN  
String header=con.getHeaderFieldKey(i); ^s&1,  
if(header!=null) 2_]"9d4  
//responseHeaders.put(header,httpConnection.getHeaderField(header));  XVKR}I  
Utility.log(header+" : "+con.getHeaderField(header)); 2nGQD{  
else > %U  
break; H,H=y},  
} wLf=a^c#  
} GCTf/V\#  
,#P eK(  
f._FwD  
public void splitterStop() n-7|{1U  
{ ,!?&LdPt>  
bStop = true; k )T;WCia  
} wZA(><\  
"`AIU}[_I  
UlN+  
} R8 lBh Ls  
45;{tS.z,B  
CYZx/r<  
/* ?=;dNS@i@  
**FileAccess.java OJL?[<I  
*//文件访问(定位,写) /M;A)z  
package NetFox; MR@*09zP(?  
import java.io.*;  OBCRZ   
4M&6q(389  
):lq}6J#  
public class FileAccessI implements Serializable{ (&U8NeWZ  
{Y! -]_ 5  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 8N|y   
RandomAccessFile oSavedFile; vq~btc.p{&  
long nPos; ?6gC;B  
N!}r(Dd*  
9?M><bBX  
public FileAccessI() throws IOException \i-HECc"U  
{ (@H'7,  
this("",0); 6jiz$x  
} jMvWS71  
'W/E*O6BY  
IZV D.1  
public FileAccessI(String sName,long nPos) throws IOException .OHjn|  
{ {VPF2JFB[  
oSavedFile = new RandomAccessFile(sName,"rw"); Gmi w(T  
this.nPos = nPos; JR1/\F<}  
oSavedFile.seek(nPos); 85<zl|ZD  
} OE(Z)|LF  
D<zgs2Ex  
3sf+ uoV  
public synchronized int write(byte[] b,int nStart,int nLen) >900O4  
{ $4\,a^  
int n = -1; ]C =+  
try{ &xlz80%  
oSavedFile.write(b,nStart,nLen); *OT6)]|k  
n = nLen; YH( 54R  
} z (,%<oX  
catch(IOException e) VemgG)\  
{ fT-yY`  
e.printStackTrace (); e5_:15%R\  
} G9.+N~GZ.  
D_%y&p?<Ls  
%.kJ@@_e  
return n; g_\U-pzr  
} 6_a42#  
hVe@:1og#  
8kz7*AO  
} Q]7Rqslz  
Br2ZloJ@+  
G!J{$0.  
/* x;,H>!r"i  
**SiteInfoBean.java }\E2Z[  
*/ smLXNO  
package NetFox; +SGM3tY  
T&Y?IE}  
t0*JinK I  
public class SiteInfoBean { yp=(wcJ  
D&f(h][hH?  
Zb)j2Xgl  
private String sSiteURL; //Site's URL []D@"Bz  
private String sFilePath; //Saved File's Path $okGqu8z.O  
private String sFileName; //Saved File's Name "=0#pH1o  
private int nSplitter; //Count of Splited Downloading File Y4Hi<JWo  
n%lY7.z8d  
_u$X.5Q;  
public SiteInfoBean() io_4d2uBh  
{//nSplitter的缺省值为5 _q >>]{5  
//default value of nSplitter is 5 /=9t$u|  
this("","","",5); 8-Ik .,}  
} je6H}eWTC6  
zT[[WY4  
] 8sVXZ  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Ij_Y+Mnl4:  
{ Suixk'-  
sSiteURL= sURL; k\UDZ)TQV  
sFilePath = sPath; >y%*HC!G  
sFileName = sName; S&jZYq**  
this.nSplitter = nSpiltter; *xxG@h|5n  
9IgozYj  
I4kN4*d!N,  
} tH0=ysf  
(^-i[aJY  
lPL>8.j  
public String getSSiteURL() FWNO/)~t  
{ c!Gnd*!?-  
return sSiteURL; <(rf+Ou>I  
} -I7"9}j3  
-,NiSh}A  
1s4+a^ &  
public void setSSiteURL(String value) u 9Wi@sO#  
{ :jB8Q$s  
sSiteURL = value; iV5x-G`  
} H-GlCVq~  
X kZ82w#b  
@G  0k+  
public String getSFilePath() RI_:~^nO{r  
{ |EuWzhNAO  
return sFilePath; Ur`Ri?  
} ob=GB71j55  
f!;4 -.p`  
*Z"9QX  
public void setSFilePath(String value) W-9^Ncp  
{ 0;,4.hsh  
sFilePath = value; ZOGH.`  
} [m7^Euury  
8<}f:9/  
|7Z7_YWs  
public String getSFileName() (J(JB}[X,  
{ f(Q-W6  
return sFileName; Sr1xG%;|/  
} (;2J}XQvO~  
{64od0:T  
/an$4?":~  
public void setSFileName(String value) 2 fp\s5%J}  
{ WyH2` xxX  
sFileName = value; $Yh7N5XH,  
} OHixOI$O  
5bZf$$b  
#gbJ$1s  
public int getNSplitter() `z<k7ig  
{ qiQS:0|_  
return nSplitter; qSh^|;2?R  
} +qsNz*@p"  
]r;-Lx{F  
ydOJ^Yty  
public void setNSplitter(int nCount) j,")c'r&dD  
{ y=)Cid  
nSplitter = nCount; B`,4M&  
} Rckqr7q  
} .b*%c?e  
a=*&OW  
#% PnZ /  
/* V=}AFGC85  
**Utility.java cx?t C#t  
*/ J%c4-'l  
package NetFox; '1]Iu@?  
JiL%1y9|  
Pl4$`Qw#y  
public class Utility { OM,-:H,  
B>, O@og  
Op^r}7  
public Utility() $OK}jSH*v)  
{ %lsk> V  
a=3?hVpB  
O(BAw  
} x}I'W?g  
Jwzkd"D  
//线程睡眠 z>$AZ>t%J$  
public static void sleep(int nSecond) K@u\^6419  
{ Yoy}Zdu}h  
try{ _Wn5* Pi%Z  
Thread.sleep(nSecond); -gZI^EII  
} NMYkEz(&R  
catch(Exception e) N0EJHS,>e  
{ C.M]~"e  
e.printStackTrace (); Y <;A989D  
} 8w &A89  
} ).HYW _Yih  
J0@ ^h  
//日志 yZJR7+  
public static void log(String sMsg) wmh[yYWc  
{ :|i jCg+  
System.err.println(sMsg); umV5Y`  
} S EdNH.|I  
7XLz Ewa  
6@_Vg~=S  
public static void log(int sMsg) g:bw;6^ u  
{ ^M60#gJ  
System.err.println(sMsg); u\gPx4]4c  
} _bp9UJ  
} NWCJ|  
{J-kcD!bz`  
p-QD(+@M  
/* O+U9 p  
**TestMethod.java r9@4-U7v&  
*/ V4Yw"J  
package NetFox; HS!O;7s'  
<=KtRE>$  
GY9CU=-  
public class TestMethod { _B4H"2}[Y  
;<qv-$P  
Zr`pOUk!4  
public TestMethod() 8jyg1NN D  
{ ///xx/weblogic60b2_win.exe )LESdX  
try{ ~x`BV+R  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Aa^%_5  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); i^LLKx7M&  
SiteFileFetch fileFetch = new SiteFileFetch(bean); z)$X/v  
fileFetch.start(); c=]z%+,b]  
} ]AjDe]  
catch(Exception e){e.printStackTrace ();} Ar@" K!TS  
=1' / ?  
>gNVL (  
} `4V_I%lJ&  
$ K>.|\  
y#-mj,e  
public static void main(String[] args) OmO/x  
{ 9Yg=4>#$  
new TestMethod(); $@y<.?k>UP  
} RGrra<  
} Z/nTI 0N{  
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