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http断点续传简单实现(java)

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/* ZSb+92g{L$  
**SiteFileFetch.java Z|wDM^Lf  
*/ TrA Uu`?#  
package NetFox; > n\ Q [W  
import java.io.*; (_<n0  
import java.net.*; <7Lz<{jaJ  
@V u[Tg}J  
]qRz!D%@^  
public class SiteFileFetch extends Thread { m_f^#:  
9 9-\cQv  
LEa:{s<:  
SiteInfoBean siteInfoBean = null; //文件信息Bean Wm_-T]#_  
long[] nStartPos; //开始位置 |(g2fByDf  
long[] nEndPos; //结束位置 $MGd>3%y  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 Y[,C1,  
long nFileLength; //文件长度 \MPy"uC  
boolean bFirst = true; //是否第一次取文件 8Qy |;T}  
boolean bStop = false; //停止标志 a]ey..m  
File tmpFile; //文件下载的临时信息 ~epkRO="  
DataOutputStream output; //输出到文件的输出流 kS!*kk*a  
h {btT  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Bqj *{m  
public SiteFileFetch(SiteInfoBean bean) throws IOException Rznr 9L  
{ AkC\CdmA  
siteInfoBean = bean; pDfF'jt9  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); z05pVe/5  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); -fn~y1  
if(tmpFile.exists ()) c+VUk*c3  
{ 8t; nU;E*  
bFirst = false; 7.-|3Wcg  
read_nPos(); CeemR>\t  
} 0\A[a4crj  
else `R;XN-  
{ n$iz   
nStartPos = new long[bean.getNSplitter()]; T;7|d5][  
nEndPos = new long[bean.getNSplitter()]; $^F2  
} 4Qs#ws])  
i^Q^F  
$>Do&TU   
wDzS<mm  
} s3S73fNOk  
I.x>mN -0  
u]-$]zIH  
public void run() mmti3Y  
{ Fx2&ji6u  
//获得文件长度 7IR n  
//分割文件 QG ia(  
//实例FileSplitterFetch :}cAq/  
//启动FileSplitterFetch线程 EY(4 <;)  
//等待子线程返回 0jMrL\>C  
try{ oizoKwp%  
if(bFirst) Dc5XU3Eu`  
{ s RB8 jY  
nFileLength = getFileSize(); _1QNO#X  
if(nFileLength == -1) Pc-HQU  
{ A,@"(3  
System.err.println("File Length is not known!"); ~-x\E#(  
} ?e*vvu33!  
else if(nFileLength == -2) ~$<@:z{*  
{ pK%'S  
System.err.println("File is not access!"); bK7DGw`1  
} qm_\#r  
else +=v|kd  
{ QaV*}W  
for(int i=0;i<nStartPos.length;i++) &0myA_So  
{ [;}c@  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); z Ey&%Ok  
} 9i@*\Ada  
for(int i=0;i<nEndPos.length-1;i++) z;)% i f6  
{ $U1'n@/J  
nEndPos = nStartPos[i+1]; TzjZGs W[V  
} 08Gr  
nEndPos[nEndPos.length-1] = nFileLength; #v1 4"sZ}  
} uM$=v]e^ 4  
} <=lP6B  
x.aUuC,$x  
n=~?BxB  
//启动子线程 Iq9+  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; ]d0Dd")n  
for(int i=0;i<nStartPos.length;i++) v%r!}s  
{ XT\;2etVL  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), o3yZCz  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), #&^+hx|  
nStartPos,nEndPos,i); :Wln$L$  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); pc #^ {-  
fileSplitterFetch.start(); ?hO*~w;UU|  
} +!rK4[W'  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), - >2ej4C  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); /V^S)5r  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 6 BMn7m?  
nEndPos = " + nFileLength); 8LOzL,Ah  
// fileSplitterFetch[nPos.length-1].start(); R_csKj  
&,+ZN A`P  
iw%DQ }$  
//等待子线程结束 yTk9+>  
//int count = 0; p[RD[&#b  
//是否结束while循环 h6#  
boolean breakWhile = false; Jx_4:G  
Q{RHW@_/  
GIp?}tM  
while(!bStop) 1FuChd  
{ V6c?aZ,O  
write_nPos(); ({)_[dJ'  
Utility.sleep(500); q /#O :Q  
breakWhile = true; j_Fr3BWS  
~0`Pe{^*  
;YB8X&H$  
for(int i=0;i<nStartPos.length;i++) DZvpt%q  
{ h<uQ~CQg  
if(!fileSplitterFetch.bDownOver) {)G3*>sG3  
{ B $HQFdTli  
breakWhile = false; oR~+s &c  
break; 8.@ yD^'  
} Zhw _L  
} u%2u%-w  
if(breakWhile) E:7vm@+  
break; PUI.Un2C_  
)]>9\(  
$*tuv ?  
//count++; H_ x35|"  
//if(count>4) 0-QkRr_ I  
// siteStop(); .UJk0%1  
} Z"P{/~HG  
o)NWsUXf  
G|o-C:~  
System.err.println("文件下载结束!"); E;N+B34  
} #)XO,^s.  
catch(Exception e){e.printStackTrace ();} r`lgK2r\  
} sbgRl%  
] O 2_&cs  
2)G ZU  
//获得文件长度 >$}nKPC,Y  
public long getFileSize() lcih [M6z  
{ !0cfz5t  
int nFileLength = -1; yfV{2[8ux  
try{ P0W%30Dh  
URL url = new URL(siteInfoBean.getSSiteURL()); pt=[XhxC(>  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); p@P[pzxI  
httpConnection.setRequestProperty("User-Agent","NetFox"); 9[:nW p^  
eudPp"Km  
 -"<eq0  
int responseCode=httpConnection.getResponseCode(); M jHeUf  
if(responseCode>=400) GSl\n"S]=  
{ lp4sO#>`  
processErrorCode(responseCode); l_DPlY  
return -2; //-2 represent access is error BWd?a6nU}  
} U9Y'eP.2  
(|Xf=q,Le  
A1i-QG/6  
String sHeader; l*h6 JgU  
EQg 6*V  
Yd]f}5F  
for(int i=1;;i++) b\}`L"  
{  Vb/J`  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Y5K!DMK Y  
//Utility.log(in.readLine()); :5;[Rg5 2  
sHeader=httpConnection.getHeaderFieldKey(i); lG q;kIQ  
if(sHeader!=null) 7m8L!t9  
{ )Y)7p//  
if(sHeader.equals("Content-Length")) X~lOFH;}q  
{ cLamqZf3  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); fE7Kv_N-%  
break; vG<Mz?wr  
} 1V)0+_Yv  
} 5o&L|7]  
else <{e0 i  
break; (RGl, x:  
} 1`b?nX  
} 9;.dNdg>  
catch(IOException e){e.printStackTrace ();} LM0 TSB?  
catch(Exception e){e.printStackTrace ();} Lc+)#9*d  
NJn~XCq  
OS,-dG(  
Utility.log(nFileLength); Rnj2Q!C2  
T Li0*)}  
ci ,o'`Q  
return nFileLength; |U12 fuQ  
} |`#[jHd  
yl|+D]  
|IZG `3  
//保存下载信息(文件指针位置) @Yy=HV  
private void write_nPos() L{aT"Of{X  
{ }eBy p  
try{ I#9A\.pO  
output = new DataOutputStream(new FileOutputStream(tmpFile)); !SVW}Q=5#  
output.writeInt(nStartPos.length); =n%?oLg^  
for(int i=0;i<nStartPos.length;i++) BC&Et62*  
{ (gz|6N  
// output.writeLong(nPos); J0^p\mG  
output.writeLong(fileSplitterFetch.nStartPos); _)lK.5  
output.writeLong(fileSplitterFetch.nEndPos); uI.4zbgl[  
} C!v0*^i  
output.close(); ?zxKk(J  
} "x&H*"  
catch(IOException e){e.printStackTrace ();} s|d L.@0,L  
catch(Exception e){e.printStackTrace ();} =T;%R^@  
} ZO:{9vt=/  
k?1cxY s  
;sb0,2YyP  
//读取保存的下载信息(文件指针位置) @ -g^R4e<  
private void read_nPos() O`H[,+vm[  
{ +HUI1@ql  
try{ (,HA Os  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Xo }w$q5  
int nCount = input.readInt(); eF!c< Kcr  
nStartPos = new long[nCount]; E/Y.f  
nEndPos = new long[nCount]; \U p<m>3\  
for(int i=0;i<nStartPos.length;i++) bMf +/n  
{ ;v#~ o*  
nStartPos = input.readLong(); ;z!~-ByzL  
nEndPos = input.readLong(); (Z sdj  
}  Ws}u4t  
input.close(); 7 -bU9{5  
} $  5  
catch(IOException e){e.printStackTrace ();} .GLotc  
catch(Exception e){e.printStackTrace ();} +n1}({7m  
} 1,BtOzuRo  
j @sd x)1+  
7vgz=- MZ#  
private void processErrorCode(int nErrorCode) {U7j  
{ 0p:n'P  
System.err.println("Error Code : " + nErrorCode); e$ E=n  
} V<P@hAAr  
h?fv:^vSi  
i7:j(W^I8  
//停止文件下载 no^I![_M  
public void siteStop() n(-XI&Kn  
{ r's4-\  
bStop = true; 8V.x%T  
for(int i=0;i<nStartPos.length;i++) %]RzC`NZ  
fileSplitterFetch.splitterStop(); N!^U{;X7/  
|\Jpjm)?  
q48V|6X'q  
} AgO:"'c  
} /tx_I(6F?|  
//负责部分文件的抓取 wIL5-k,  
**FileSplitterFetch.java : !J!l u  
*/ `[/BG)4  
package NetFox; bZ:w_z[3=  
|Ax~zk;  
&\`=}hB  
import java.io.*; &`0heJ 5Yn  
import java.net.*; *}A J7]  
KGzBK:  
:1=mNrg  
public class FileSplitterFetch extends Thread { EivZI<<a  
M*{ EK  
FG1$_zN |  
String sURL; //File URL _K8ob8)m  
long nStartPos; //File Snippet Start Position !SKEL6~7  
long nEndPos; //File Snippet End Position X{<j%PdC  
int nThreadID; //Thread's ID |Zncr9b  
boolean bDownOver = false; //Downing is over GYyP+7K4l[  
boolean bStop = false; //Stop identical zT`LPs6T  
FileAccessI fileAccessI = null; //File Access interface ci6j"nKci  
x}].lTjD  
I 4gyGg$H  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException B7_:,R.l  
{ jvCk+n[  
this.sURL = sURL; "PLZZL$+  
this.nStartPos = nStart; dGTAZ(1W  
this.nEndPos = nEnd; %)u5A !"  
nThreadID = id; gfFP-J3cN  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 )!e-5O49r  
} Ri"3o  
C/tn0  
rW&8#&  
public void run() S_ e }>-  
{ 7Oru{BQ">  
while(nStartPos < nEndPos && !bStop) }`\+_@ w  
{ gNo.&G [  
/0\m;&  
{{SeD:hx  
try{ ^t?P32GJ  
URL url = new URL(sURL); Oy&Myjny<  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); lpj$\WI=  
httpConnection.setRequestProperty("User-Agent","NetFox"); f'TdYG  
String sProperty = "bytes="+nStartPos+"-"; 9#@dQ/*  
httpConnection.setRequestProperty("RANGE",sProperty); 39BGwKXb  
Utility.log(sProperty); K.dgQ-vn  
-_4U+Cfmtl  
[x'xbQLGd  
InputStream input = httpConnection.getInputStream(); vB#&XK.aW  
//logResponseHead(httpConnection); W,}HQ  
$ GL$ iA  
KaZ$!JfT  
byte[] b = new byte[1024]; AFF7fK  
int nRead; /t01z~_  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) *U)!9DvA  
{ ?6; +.h\  
nStartPos += fileAccessI.write(b,0,nRead); K #}DXq  
//if(nThreadID == 1) wMT?p/9Blm  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); k]] (I<2  
} #7/_Usso  
#y~^!fdp9  
!/BXMj,=  
Utility.log("Thread " + nThreadID + " is over!"); ezY _7  
bDownOver = true; bN8GRK )  
//nPos = fileAccessI.write (b,0,nRead); ~Q0gSazXFt  
} n[[rI0]g  
catch(Exception e){e.printStackTrace ();} ?*tb|AL(R  
} .u>IjK^  
} 1aS[e%9Mg  
o=X6PoJ N_  
? !MDg_oHd  
//打印回应的头信息 \8'fy\  
public void logResponseHead(HttpURLConnection con) q1;}~}W;z4  
{ |nk&ir6  
for(int i=1;;i++) =P<gZ-Cm  
{ $RuJm\f  
String header=con.getHeaderFieldKey(i); rL w,?  
if(header!=null) NU-({dGK}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ik=~`3Zp0  
Utility.log(header+" : "+con.getHeaderField(header)); /o*r[g7<  
else ~B'K_#  
break; XnHcU=~q  
} h1^q};3!W\  
} )F,H(LblH  
jV;&*4if  
NX4!G>v  
public void splitterStop() FYFP 6ti  
{ ]2T=%(*  
bStop = true; @V Bv}Jo  
} Tar tV3;`  
uHkL$}C  
U+3,(O  
} ;\DXRKR  
<(TTYf8lS  
 (f,D$mX  
/* }eXzs_  
**FileAccess.java }nvH Eo  
*//文件访问(定位,写) /d ?)  
package NetFox; rDX_$,3L  
import java.io.*; z _~ 5c  
)q&=x2`  
0zCe|s.S&  
public class FileAccessI implements Serializable{ N|EH`eu^i  
?%J{1+hY  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 ,3Y~ #{,i  
RandomAccessFile oSavedFile; :vz_f$=  
long nPos; .Wv2aJq  
<03@cs  
qsk8#  
public FileAccessI() throws IOException B @H.O!  
{ , |CT|2D>  
this("",0); T]l_B2.  
} I2hX;pk,  
R?a)2jl  
I8;pMr6  
public FileAccessI(String sName,long nPos) throws IOException X2hV)8Sk  
{ !([Q1r{u  
oSavedFile = new RandomAccessFile(sName,"rw"); (9]`3^_,J  
this.nPos = nPos; ,R5NKWo  
oSavedFile.seek(nPos); 3P-qLbJ  
} lG;RfDI-  
IT5AB?bxH  
/-Y*V*E  
public synchronized int write(byte[] b,int nStart,int nLen) ;Y5"[C9|  
{ _I l/ i&  
int n = -1; 7^P!@o$v!  
try{ B<i )je!  
oSavedFile.write(b,nStart,nLen); a1R2ocC  
n = nLen; PdcF  
} RbKAB8  
catch(IOException e) Mt(wy%{zK  
{ M)C. bo{p  
e.printStackTrace (); }\k"azQ`  
} ^o}!=aMr  
NWd%Za5K;  
( >zXapb2  
return n; c+c3C8s*8  
} <GC<uB |p  
w'oP{=y[  
SV}q8z\  
} rC V&& 09  
9oKRn c  
Nlemb:'eP3  
/* 3 &.?9  
**SiteInfoBean.java gO_{(\w*  
*/  s.&ewf\  
package NetFox; TkXD#%nFY  
a@$U?=\e  
i$gm/ZO  
public class SiteInfoBean { Sr Z\]  
Vb*q^ v  
H6X]D"Y,  
private String sSiteURL; //Site's URL dIgaw;Ch]  
private String sFilePath; //Saved File's Path ~n9BN'@x  
private String sFileName; //Saved File's Name L!s/0kBg  
private int nSplitter; //Count of Splited Downloading File s1. YH?A;  
(NK$2A/p  
RL7OFfMe  
public SiteInfoBean() vY0C(jK  
{//nSplitter的缺省值为5 mJe;BU"y]  
//default value of nSplitter is 5 6C@,&2<yK  
this("","","",5); v*`$is+  
} UhQ[|c  
XF(0>-  
W8+Daw1Nr  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) N+%E=D>  
{ NPy{ =#k4  
sSiteURL= sURL; y33+^  
sFilePath = sPath; ;M}'\.  
sFileName = sName; c'B6E1}sx  
this.nSplitter = nSpiltter; 3on]#/"1b  
58)`1p\c'  
F!OVx<  
} 0PO'9#  
HTiqErD2_  
|!:ImX@  
public String getSSiteURL() ~&B{"d  
{ @9~a3k|  
return sSiteURL; VcKufV'  
} n*~=O'  
W<C \g~\  
qXPjxTg{[  
public void setSSiteURL(String value) ~H!s{$.5  
{ M&o@~z0  
sSiteURL = value; aZEi|\VU  
} 4UD<g+|  
YSERQo  
}PdS?[R  
public String getSFilePath() <+@?V$&  
{ 9SF2  
return sFilePath; l]D?S]{a  
} ={,\6a|]:  
bE:oF9J?  
Kcv7C{-/  
public void setSFilePath(String value) V)#se"GV  
{ j]th6  
sFilePath = value; OCmF/B_  
} 4#Wczk-b  
Z]f_? @0  
))f%3_H  
public String getSFileName() ~?i;~S  
{ rmXxid  
return sFileName; /.{4 KW5  
} . U|irDO  
#G2~#\  
u:#+R_0#97  
public void setSFileName(String value) \|9@*]6:  
{ Im7<\ b@  
sFileName = value; G?$|aQ0j  
} H0<(j(JK  
<>JN&#3?  
[r,a0s  
public int getNSplitter() MTJ ."e<B  
{ X+zFRL%  
return nSplitter; tSX<^VER7  
} B1dVHz#  
L1=+x^WQ  
.%)FK#s-  
public void setNSplitter(int nCount) ;Q"xXT`;:  
{ xG:eS:iT  
nSplitter = nCount; `B6~KZ  
} U6^x(2De  
} I^erMQn[ z  
_~V7m  
BoQLjS{kN  
/* LVNq@,s  
**Utility.java ?m.WqNBH7  
*/ S9/oBxGN  
package NetFox; G"w ?{W @  
`x%v& >  
jo 0 d#  
public class Utility { )p*I(y  
gB/4ro8  
EC(,-sz\Z  
public Utility() ZC}'! $r7  
{ sb"z=4  
So>P)d$8+  
a@( 4X/|  
} DM {r<?V  
W4n;U-Hb  
//线程睡眠 ^Ud1 ag!-  
public static void sleep(int nSecond) xs+pCK|  
{ Ia_I~ U$  
try{ |  RMIV  
Thread.sleep(nSecond); *J^l r"%c  
} o5=1  
catch(Exception e) ~uqpF-.  
{ _<tWy+.  
e.printStackTrace (); 1>hY!nG h  
} hx|Cam"  
} wdS4iQD  
_dOR-<  
//日志 fik*-$V`  
public static void log(String sMsg) DUBEh@  
{ =eG?O7z&  
System.err.println(sMsg); l 2&cwjc  
} hP1}Do  
8!8 yA  
)1 ]P4  
public static void log(int sMsg) UjCQ W:[  
{ Ky"]L~8$  
System.err.println(sMsg); +ob<? T  
} g\9I&z~?  
} _dQVundH  
@JJ,$ ?  
M"cB6{st[  
/* ['9awgkr/  
**TestMethod.java 0\fV'JDOR  
*/ :[icd2JCw]  
package NetFox; tBR"sBiws  
Ik{[BRzUgt  
\:>GF-Z(  
public class TestMethod { \HR<^xY  
"},0Cs  
qg521o$*  
public TestMethod() l!r2[T]I@7  
{ ///xx/weblogic60b2_win.exe 5]C}044  
try{ `re9-HM  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 7G,{BBB  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); -M]NdgI  
SiteFileFetch fileFetch = new SiteFileFetch(bean); <'s_3AC  
fileFetch.start(); P .I <.e  
} i WCR 5c=  
catch(Exception e){e.printStackTrace ();} Q[g>ee  
zj~(CNE  
O>8|Lc  
} LOm*=MVex  
UO3QwZ4j;  
>%qk2h>  
public static void main(String[] args) ,&+"|,m  
{ Gyo[C98  
new TestMethod(); }^T7S2_Qy  
} =E{e|(1+u  
} 6yDc4AX  
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