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http断点续传简单实现(java)

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/* /Sj_y*x1e  
**SiteFileFetch.java ,.7vBt6 p  
*/ MB O,\t.  
package NetFox; ;tr)=)q &  
import java.io.*; |_I[1%&`N  
import java.net.*; |Gc&1*$  
npj5U/  
Rp eBm#E2  
public class SiteFileFetch extends Thread { O3xz|&xY&  
m)k-uWc$C  
I}%mfojC  
SiteInfoBean siteInfoBean = null; //文件信息Bean }K;iJ~kD1  
long[] nStartPos; //开始位置 -x?Hj/  
long[] nEndPos; //结束位置 D(@SnI+  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 \E&thp  
long nFileLength; //文件长度 JD-Becz  
boolean bFirst = true; //是否第一次取文件 $Q ffrU'  
boolean bStop = false; //停止标志 '\'7yN'  
File tmpFile; //文件下载的临时信息 >3$uu+p1F  
DataOutputStream output; //输出到文件的输出流 !Sfe{/$w  
&<t79d%{  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) 3Tw%W0q  
public SiteFileFetch(SiteInfoBean bean) throws IOException ](n69XX_  
{ !ABLd|tP  
siteInfoBean = bean; PHQcstW  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 2<m Q,,j  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ' tSnH&c  
if(tmpFile.exists ()) f~iML5lG  
{ Xky@[Td*  
bFirst = false; wOM<X hZ  
read_nPos(); U,d2DAvt  
} v C-[#]<  
else T7s+9CE  
{ 2_I+mQ  
nStartPos = new long[bean.getNSplitter()]; -G!6U2*#  
nEndPos = new long[bean.getNSplitter()]; `|JI\&z  
} I*9Gb$]=  
BiE$mM  
#4lHaFq  
P;>!wU~*  
} 8nf4Jk8r  
fGo_NB  
kp.|gzA6  
public void run() Ltl]j*yei  
{ _rG-#BKW8L  
//获得文件长度 3U>S]#5}  
//分割文件 wH!}qz /  
//实例FileSplitterFetch Iw*C*%}[Z  
//启动FileSplitterFetch线程 e00RT1L  
//等待子线程返回 Z{ %Uw;d  
try{ JkJhfFV  
if(bFirst) > `0| X  
{ T 77)Np  
nFileLength = getFileSize(); [e1\A&T  
if(nFileLength == -1) #yX^?+Rc  
{ do*Wx2:R  
System.err.println("File Length is not known!"); $Q#?`j  
} 37~rm  
else if(nFileLength == -2) j}"]s/= 6  
{ /LSq%~UF  
System.err.println("File is not access!"); vg5E/+4gp%  
} L#[HnsLp_  
else #'#4hJ*YC  
{ Dn: Yi8=  
for(int i=0;i<nStartPos.length;i++) VDPxue  
{ g8Ok ^  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); A?\h|u<  
} s~/57S  
for(int i=0;i<nEndPos.length-1;i++) ]m RF[b$  
{ Fu#Y7)r  
nEndPos = nStartPos[i+1]; +OKA_b"wB  
} 1RmBtx\<  
nEndPos[nEndPos.length-1] = nFileLength; dPRtN@3  
} z=u~]:.1O  
} +7`u9j.  
l;XUh9RF`A  
FU^Y{sbDg  
//启动子线程 /Ql6]8.P  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; VN?<[#ij  
for(int i=0;i<nStartPos.length;i++) $B*qNYpPy.  
{ HH+TjX/b  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Qb@BV&^y&  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), d"z *Nb  
nStartPos,nEndPos,i); B6-AIPb  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); |WQD=J%~(  
fileSplitterFetch.start(); oJhEHx[f  
} hcj{%^p  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), {E3;r7  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); }`#j;H$i  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", zf}rfn  
nEndPos = " + nFileLength); u|(aS^H=q  
// fileSplitterFetch[nPos.length-1].start(); -=@K %\\~5  
><MGZ?-N  
"pR $cS  
//等待子线程结束 <<i=+ed8eP  
//int count = 0; >qr=l,Hi  
//是否结束while循环 F>p%2II/  
boolean breakWhile = false; hU |LFjc  
}o~Tw?z-|  
)kFme=;  
while(!bStop) ]eY Qio!  
{ 5L/Yi  
write_nPos(); Q,ZkeWQ7%  
Utility.sleep(500); (L]T*03#  
breakWhile = true; D-;J;m \  
)tJL@Qo  
77)OW $G  
for(int i=0;i<nStartPos.length;i++) 9t,aT!f  
{ cKaL K#~  
if(!fileSplitterFetch.bDownOver) mm3zQ!2j.  
{ =9#i<te  
breakWhile = false; N;%j#(v j  
break; O<gP)ZW~  
} E>o&GYc  
} T9aTEsA[U  
if(breakWhile) '&rw=.cU  
break; "-G.V#zI  
[R roHXdk+  
h}Fu"zK  
//count++; Yk(NZ3O  
//if(count>4) z1z =P%WK  
// siteStop(); \UV T_=Y  
} g`y/ _  
b#bO=T$e-  
89 _&X[X  
System.err.println("文件下载结束!"); #MmmwPB_  
} J$o[$G_Z  
catch(Exception e){e.printStackTrace ();} 1',+&2)oj  
} k i~Raa/e  
h+\$ Z]  
Ke'YM{  
//获得文件长度 oY| (M_;  
public long getFileSize() `K1PGibV  
{ U`},)$  
int nFileLength = -1; ?)i6:76(  
try{ gME:\ud$  
URL url = new URL(siteInfoBean.getSSiteURL()); 9 ayH:;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); O% j,:t'"  
httpConnection.setRequestProperty("User-Agent","NetFox"); So3,Z'z=  
Cf8R2(-4  
lk5_s@V l  
int responseCode=httpConnection.getResponseCode(); 7!]k#|u  
if(responseCode>=400) aC $h_  
{ F!DrZd>\  
processErrorCode(responseCode); *}50q9)/  
return -2; //-2 represent access is error iX&Z  
} 2b vYF ;<r  
@pyA;>U  
74</6T]^  
String sHeader; /0'fcjOaQ  
y"{UN M|R  
r)*_,Fo|  
for(int i=1;;i++) 3@#,i<ge:  
{ -0[>}!l=G  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); (5CX*)R  
//Utility.log(in.readLine()); J{v6DYhi  
sHeader=httpConnection.getHeaderFieldKey(i); U/~Zk@3j  
if(sHeader!=null) [m@e^6F0U  
{ 6M2i? c  
if(sHeader.equals("Content-Length")) Xlgz.j7XR  
{ .-gm"lB  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); LQuYCfj|  
break; o>!~*b';g,  
} 9 ;! uV>-H  
} ** "s~  
else s`dkEaS  
break; zjhR9  
} 8I|1P l  
} *8(t y%5F0  
catch(IOException e){e.printStackTrace ();} TO8\4p*tE  
catch(Exception e){e.printStackTrace ();} P7^TRrMF  
}pU!1GsO  
`^@g2c+d  
Utility.log(nFileLength); 6 I>xd  
h_}BmJh_  
?7uStqa  
return nFileLength; KH CdO  
} M 2U@gC|{  
IT{.^rP  
Z2Y583D  
//保存下载信息(文件指针位置) wLg:YM"  
private void write_nPos() V%Z[,C u+  
{ h3vm< R;  
try{ 0L 4]z'5  
output = new DataOutputStream(new FileOutputStream(tmpFile)); cUX]tiC0  
output.writeInt(nStartPos.length); =&<$I  
for(int i=0;i<nStartPos.length;i++) 1Rb<(%   
{ 7~k~S>sO  
// output.writeLong(nPos); ocuNrkZ  
output.writeLong(fileSplitterFetch.nStartPos); -t706(#k  
output.writeLong(fileSplitterFetch.nEndPos); )r-|T&Sn  
} ~`Gcq"7, !  
output.close(); X_Of k  
} M@z_Z+q 9  
catch(IOException e){e.printStackTrace ();} fuwpp  
catch(Exception e){e.printStackTrace ();} ag*Hs<gi  
} Toa#>Z*+Rb  
0DP%44Cv9  
=.3P)gY)  
//读取保存的下载信息(文件指针位置) _s#/f5<:B  
private void read_nPos() -^NAHE$bW  
{ 71,0v`Z<  
try{ smQpIB;  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); jL[Is2<@  
int nCount = input.readInt(); ;Bc<u[G  
nStartPos = new long[nCount]; 9 h{:!  
nEndPos = new long[nCount]; "$wPq@  
for(int i=0;i<nStartPos.length;i++) r z>zdj5}  
{ Y+5A2Z)f[  
nStartPos = input.readLong(); pOe`*2[  
nEndPos = input.readLong(); )}g4Rvr  
} `cTsS  
input.close(); ($ 1<Dj:  
} Z[A|SyZp  
catch(IOException e){e.printStackTrace ();} M#gGD-  
catch(Exception e){e.printStackTrace ();} 5 <>agK]  
} gpTF^.(  
%2FCpre;  
?tM].\  
private void processErrorCode(int nErrorCode) DcvmeGl  
{ M`,Z#)Af  
System.err.println("Error Code : " + nErrorCode); ,, -[P*@  
} #p:jKAc3  
1Z{p[\k  
)@&?i.  
//停止文件下载 d?+oT0pCH  
public void siteStop() bT6)(lm  
{ ff+9(P>*  
bStop = true; =2V;B  
for(int i=0;i<nStartPos.length;i++) q.K$b  
fileSplitterFetch.splitterStop(); ClVpb ew  
GeW$lA I  
^# g;"K0  
} z4%F2Czai&  
} W1,L>Az^Ts  
//负责部分文件的抓取 |$-d, ] V  
**FileSplitterFetch.java l+kg4y  
*/ NCh(-E  
package NetFox; XIW: Nk!S  
eX),B  
R~?;KJ  
import java.io.*; vrEaNT$J-  
import java.net.*; oL/^[TXjH  
XjM)/-w  
X;a{JjN  
public class FileSplitterFetch extends Thread { rH_:7#.E  
uEO2,1+  
2n r UE  
String sURL; //File URL GP k Cgb(  
long nStartPos; //File Snippet Start Position h[)aRo  
long nEndPos; //File Snippet End Position Oh85*3  
int nThreadID; //Thread's ID ? F), 4Q  
boolean bDownOver = false; //Downing is over L5P}%1 _  
boolean bStop = false; //Stop identical w0`L)f5v  
FileAccessI fileAccessI = null; //File Access interface wk 7_(gT`0  
h+d;`7Z>  
g.sV$.T2K  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException cg5{o|x  
{ uNGxz*e  
this.sURL = sURL; ] ,aAzjZ  
this.nStartPos = nStart; xW ZcSIH!  
this.nEndPos = nEnd; 80" =Qu{s  
nThreadID = id; Br$PL&e~  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 wg~`Md  
} .*ovIU8  
SX<mj  
aC6b})^  
public void run() YxqQg  
{ eBRP%<=>D  
while(nStartPos < nEndPos && !bStop) 2%yJo7f$[  
{ ;GE u.PdxB  
h*LL(ow5  
N~KRwsDH  
try{ t'/;Z:  
URL url = new URL(sURL); _o"3gfH&sJ  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); A0k>Nb\c3  
httpConnection.setRequestProperty("User-Agent","NetFox"); g>-[-z$E3  
String sProperty = "bytes="+nStartPos+"-"; .qPfi] ty  
httpConnection.setRequestProperty("RANGE",sProperty); 9{#|sABGD  
Utility.log(sProperty); 'i-O  
n\p\*wb  
D}U<7=\3H  
InputStream input = httpConnection.getInputStream(); YGmdiY:;1  
//logResponseHead(httpConnection); Qg.:w  
+B|X k[  
 ;I@L  
byte[] b = new byte[1024]; #E@i@'T  
int nRead; YfU#kvE'  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) R51!j>[fqM  
{ N9|.D.#MF  
nStartPos += fileAccessI.write(b,0,nRead); Oo .Qz   
//if(nThreadID == 1) ABDUp:  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [1MEA;  
} {4q:4 i  
?7ZlX?D[  
Y-{BY5E.  
Utility.log("Thread " + nThreadID + " is over!"); zQ+t@;g1  
bDownOver = true; .O.R  
//nPos = fileAccessI.write (b,0,nRead); q,&T$Tw  
} Y--8v#t  
catch(Exception e){e.printStackTrace ();} kw}1CXD  
} 4^^rOi0  
} jch8d(`?d  
eV%bJkt.  
Y6PA\7Y\  
//打印回应的头信息 xJGeIh5  
public void logResponseHead(HttpURLConnection con) s@iCfXU  
{ *?"{T;4u~O  
for(int i=1;;i++) <BA&S _=4  
{ "uC*B4`  
String header=con.getHeaderFieldKey(i); K7VG\Ec  
if(header!=null) Vgk,+l!4  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); wKbymmG  
Utility.log(header+" : "+con.getHeaderField(header)); gI3rF=  
else (32nI?)a  
break; 9?c^~77  
} 5/ju it  
} .)zISa*Xy  
2:F  
" ?,6{\y,  
public void splitterStop() (\>'yW{f  
{ -Lb^O/  
bStop = true; ,4,c-   
} ZHasDZ8  
+eXfT*=u5  
0Wm-` ZA  
} S$WM&9U   
Zw{tuO7}K  
jsQ$.)nO  
/* 1iDo$]TEK  
**FileAccess.java Af<>O$$6  
*//文件访问(定位,写) W10fjMC}^  
package NetFox; @NE#P&f  
import java.io.*; b\S}?{m5  
W2N7  
.&xNJdsY  
public class FileAccessI implements Serializable{ 8m<<tv.  
dhkpkt<G8  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 4] 1a^@?  
RandomAccessFile oSavedFile; ii9/ UtIQ  
long nPos; ,+9r/}K]/  
 gV kI=J  
Fo~v.+^?  
public FileAccessI() throws IOException Y1\vt+`O  
{ 0&@ pX~h:  
this("",0); c<e\JJY5?  
} $twF93u$  
I!D*(>  
o hlVc%a  
public FileAccessI(String sName,long nPos) throws IOException $(=1A>40  
{ ]H2aYi$  
oSavedFile = new RandomAccessFile(sName,"rw"); $t}1|q|  
this.nPos = nPos; ,[ L$  
oSavedFile.seek(nPos); 1}*;  
} jRAL(r|  
0g-ESf``{n  
q(Q9FonU  
public synchronized int write(byte[] b,int nStart,int nLen) 1bkUT_  
{ K6 7? d  
int n = -1; ;i>E @  
try{ |lV9?#!  
oSavedFile.write(b,nStart,nLen); W|U1AXU7/  
n = nLen; edx'p`%d5  
} n`xh/vGm#  
catch(IOException e) E2D8s=r  
{ qw1J{xoHW  
e.printStackTrace (); qV,j)b3M  
} w-Fk&dC69  
GR `ncI$z  
2z3A"HrlA  
return n; f*Js= hvO  
} _9r{W65s  
^j}sS!p  
{m:R v&T  
} W^Y0>W~  
; bE6Y]"Rz  
B$EP'5@b  
/* \'*`te:{  
**SiteInfoBean.java ,c l<74d  
*/ [{$0E=&0  
package NetFox; 89mre;v`  
)n@3@NV  
q(^J7M)  
public class SiteInfoBean { MGDv4cFE.  
/GGu` f  
YU(*kC8   
private String sSiteURL; //Site's URL o#/iR]3  
private String sFilePath; //Saved File's Path D7/Bp4I#o  
private String sFileName; //Saved File's Name <t{AY^:r  
private int nSplitter; //Count of Splited Downloading File (=V[tI+Ngt  
A8GlE  
3>v0W@C  
public SiteInfoBean() *DzPkaYD>  
{//nSplitter的缺省值为5 0EXNq*=EE  
//default value of nSplitter is 5 vI}S6-"<  
this("","","",5); k]pD3.QJ  
} ;jI"|v{vnS  
"\?G  
y:[]+  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) %Oqe7Cx>+  
{ uf] $@6)  
sSiteURL= sURL; vyGLn  
sFilePath = sPath; ,5*xE\9G  
sFileName = sName; uiA:(2AQ  
this.nSplitter = nSpiltter; ygt)7f5  
>]8.xkQq  
UROi.976D  
} q.{/{9  
'fFdqsXr  
+Q0-jS#d  
public String getSSiteURL() S'p`ECfVMA  
{ KBA%  
return sSiteURL; @A'1D@f#  
} e/jM+%  
rd4'y~#S  
J5 ( D7rp#  
public void setSSiteURL(String value) Fxx2vTV4ag  
{ /+O8A}  
sSiteURL = value; 15DK \_;  
} Hd`p_?3]  
-GVG1#5  
HWOs@ !cL  
public String getSFilePath() z ]N~_9w  
{ Q9tE^d+%  
return sFilePath; qFbUM;  
} )0MshgM  
})vr*[  
v} ;qMceJ  
public void setSFilePath(String value) X$Vz  
{ Go7hDmu  
sFilePath = value; 5?0gC&WfN  
} ]GKx[F{)  
) '`AX\  
f<p4Pkv  
public String getSFileName() <>Ddxmw  
{ `h5eej&s(  
return sFileName; L#q9_-(#  
} ?QT"sj64w  
HTyF<K  
~7WXjVZ  
public void setSFileName(String value) #ic 2ofI  
{ ]Ja8i%LjOG  
sFileName = value; e4%*I8 ^e  
} e`M]ZG rr  
9Ru%E>el-  
Ilu`b|%D  
public int getNSplitter() ruA+1-<f  
{ 13_~)V  
return nSplitter; bRz^=  
} -7z y  
*oX]=u&  
pQ(eF0KG  
public void setNSplitter(int nCount) Ss! 3{VW  
{ 5=h'!|iY  
nSplitter = nCount; 1$D`Z/N"A  
} ;s. 5\YZ"k  
} yZ)aKwj%U  
zQ %z "tQ  
2*wO5v  
/*  >fA@tUQB  
**Utility.java \"`>-v"h  
*/ bNpIC/#0K  
package NetFox; 'L|GClc6)  
'S4EKV]  
^~<Rzq!  
public class Utility { RzJ}CT  
p6y0W`U  
&DQ4=/Z  
public Utility() ka)LK@p6  
{ eGe[sv"k  
6 #x)W  
~73i^3yf  
} UtBlP+bE?y  
i,Wm{+H-O  
//线程睡眠 3 s_k>cO=  
public static void sleep(int nSecond) Q}?N4kg  
{ Xm=^\K3  
try{ f,HzrHax  
Thread.sleep(nSecond); io r [v  
} ?}3PJVy?  
catch(Exception e) m{$tO;c/Q  
{ @f5@0A\0  
e.printStackTrace (); :&0yf;>v  
} :{i$2\DH6  
} bqQO E4;  
^c0$pqZ}r  
//日志 y.*=Ww+  
public static void log(String sMsg) kuj1 2  
{ KjwY'aYwr:  
System.err.println(sMsg); '0_j{ig  
} -Mi}yi  
Op/79 ]$  
j #I:6yA3  
public static void log(int sMsg) <A -(&+  
{ ;?L!1wklA  
System.err.println(sMsg); M o"JV  
} Jm (&G  
} hLytKPgt  
:ONuWNY N  
lO2T/1iMTW  
/* [71#@^ye  
**TestMethod.java ',H$zA?i  
*/ XHZ: mLf  
package NetFox; Z'}(t,  
Vy% :\p+  
S\3AW,c]w  
public class TestMethod { Dz8:; $/  
b%[ nB  
WE.$at{*h  
public TestMethod() y  KYP  
{ ///xx/weblogic60b2_win.exe iIGI=EwZ  
try{ $\,BpZ }3  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); iJZ|[jEDV  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); JIP+ !2  
SiteFileFetch fileFetch = new SiteFileFetch(bean); lLkmcHu  
fileFetch.start(); ||=[kjG~  
} zD)IU_GWa  
catch(Exception e){e.printStackTrace ();} 2B9 i R  
ovDJ{3L6O  
t8DL9RW'  
} &>W  (l.  
LmXF`Y$  
xMNNXPz(  
public static void main(String[] args) vcw>v={x  
{ +dCDM1{_a  
new TestMethod(); xBL$]>  
} b'7z DZI]  
} 8Q^6ibE  
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