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http断点续传简单实现(java)

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/* zCj*:n  
**SiteFileFetch.java M@!]U:5~V  
*/ Gg}LC+Y  
package NetFox; Pjj;.c 7_j  
import java.io.*; bOd sMlJkN  
import java.net.*; cdek^/  
5H'b4Cyi`  
"EOk^1,y  
public class SiteFileFetch extends Thread { C$2o o@  
EvH(Po h  
(zM+7tJH  
SiteInfoBean siteInfoBean = null; //文件信息Bean 0f=N3)  
long[] nStartPos; //开始位置 G +nY}c  
long[] nEndPos; //结束位置 3-9J "d !  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 N) V7yo?  
long nFileLength; //文件长度 JX2 |  
boolean bFirst = true; //是否第一次取文件 8eS@<[[F#  
boolean bStop = false; //停止标志 st'?3A  
File tmpFile; //文件下载的临时信息 35@Ibe~  
DataOutputStream output; //输出到文件的输出流 I).^,%>Z)  
@0/@p"j  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) g`~lIt [=  
public SiteFileFetch(SiteInfoBean bean) throws IOException H z < M  
{ B!E<uVC  
siteInfoBean = bean; A\PV@w%A i  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); #r:Kg&W2FO  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info");  ZZFI\o  
if(tmpFile.exists ()) -fSKJo#}|  
{ j_ywG{Jk  
bFirst = false; ]uj.uWD  
read_nPos(); (PT?h>|St  
} M;RnH##W  
else v\?\(Y55Y  
{ ;ijfI  
nStartPos = new long[bean.getNSplitter()]; )H37a  
nEndPos = new long[bean.getNSplitter()]; C)3$";$5)  
} uy*x~v*I]  
4K?H-Jco  
]BS{,sI  
e,j? _p  
} `w+9j-  
<2@<r t{  
7i|hlk;  
public void run() $85o%siS'  
{ y3o4%K8  
//获得文件长度 szsZFyW )+  
//分割文件 >0;"qT  
//实例FileSplitterFetch k s`  
//启动FileSplitterFetch线程 X)R] a]1A  
//等待子线程返回 /qQ2@k  
try{ ,"MUfZ  
if(bFirst) ,E8>:-boL  
{ `_{ '?II  
nFileLength = getFileSize(); uA}FuOE6  
if(nFileLength == -1) yNMwd.r[  
{ OFAqP1o{$  
System.err.println("File Length is not known!"); Ug'nr  
} tIy/QN_42  
else if(nFileLength == -2) o  >4>7  
{ xg5@;p  
System.err.println("File is not access!"); ^fiRRFr[  
} 8Carg~T@  
else Gt%?[  
{ /t6u"I~  
for(int i=0;i<nStartPos.length;i++) +n~rM'^4/  
{ ^d $e^cU  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); nhxd  
} 3$G25=eN  
for(int i=0;i<nEndPos.length-1;i++) ]~ 8N  
{ y?4=u,{C  
nEndPos = nStartPos[i+1]; L$?~TY  
} b6$A@b  
nEndPos[nEndPos.length-1] = nFileLength; PaI63 !  
} =xWW+w!r  
} nk,Mo5iqV  
MJR\ g3  
x3F L/^S  
//启动子线程 $R^"~|m3M  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; TiOvrp7B  
for(int i=0;i<nStartPos.length;i++) 5Hr"}|J<8  
{  2}`OjVS  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), ~6OdPD  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), /A>/]2(  
nStartPos,nEndPos,i); Awj`6GeJ  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 'HC4Q{b`  
fileSplitterFetch.start(); .8,lhcpY  
} 1*a2s2G '  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Y-Z.AA,  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); JeO(sj$e  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", R4o_zwWgPw  
nEndPos = " + nFileLength); ut o4bs:  
// fileSplitterFetch[nPos.length-1].start(); FNUue  
L.8-nTg"y  
SDot0`s>  
//等待子线程结束 AttDD{Ta  
//int count = 0; S]<Hx_[}  
//是否结束while循环 G6I>Ry[2?  
boolean breakWhile = false; ^rx]Y;  
z-()7WY  
U?kJXM2  
while(!bStop) {AB0 PM;-  
{ 8&3G|m1-2  
write_nPos(); 3 D\I#g  
Utility.sleep(500); FzNs >*  
breakWhile = true; -qs9a}iL  
wp} PQw:  
xY@V.  
for(int i=0;i<nStartPos.length;i++) vmL0H)q  
{ lwa  
if(!fileSplitterFetch.bDownOver) x ;kW }U  
{ xvb5-tK -  
breakWhile = false; Og^b'Kx/  
break; >R :Bkf-  
} <zrGPwk  
} hMDy;oQ  
if(breakWhile) 3PPN_Z  
break; {8'I+-  
KYMz  
Eqnc("m)  
//count++; O\8_;Gc;  
//if(count>4) Q`'w)aV  
// siteStop(); xV}-[W5sr'  
} (@[c;+x  
HvLvSy1U  
J1KV?aR  
System.err.println("文件下载结束!"); +<7`Gn(n3  
} (w `9*1NO  
catch(Exception e){e.printStackTrace ();} C/U^8,6\n  
} wgp{P>oBX  
IXc"gO  
ET.c8K1f  
//获得文件长度 1#/>[B  
public long getFileSize() ha&2V=  
{ 3]$qY_|7  
int nFileLength = -1; o)GLh^g_I'  
try{ 5R"iF+p4  
URL url = new URL(siteInfoBean.getSSiteURL()); <xv@us7  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); Yi:@>A<#  
httpConnection.setRequestProperty("User-Agent","NetFox"); t4X:I&l-M:  
Q+YYj  
{ )=h  
int responseCode=httpConnection.getResponseCode(); L"e8S%UqX  
if(responseCode>=400) gE;r;#Jt4  
{ }V:ZGP#!'  
processErrorCode(responseCode); js^+{~  
return -2; //-2 represent access is error V $Y=JK@  
} ]6#bp,  
41dB4Td5t  
G6@XRib3  
String sHeader; X?kw=x{2P  
xL&M8:  
F`))qCgg]  
for(int i=1;;i++) 9 M>.9~  
{ F/.nr  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 'ONCz  
//Utility.log(in.readLine()); {B|)!_M#  
sHeader=httpConnection.getHeaderFieldKey(i); K;)(fc  
if(sHeader!=null) tr?U/YG  
{ d%?$UnQ  
if(sHeader.equals("Content-Length")) *,az`U  
{ IPHZ~'M  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); CmP_9M?ce  
break; :yFUlO:  
} oyC5M+shP9  
} m!#'4  
else V)<Jj  
break; ^?<gz!(-  
} @'IRh9  
} \k 9EimT}  
catch(IOException e){e.printStackTrace ();} sH_B*cr3  
catch(Exception e){e.printStackTrace ();} ^L4"X~eM  
sx1w5rj.Y0  
r{mj[N'@  
Utility.log(nFileLength); 6>Dm cG:.  
w#qE#g %1  
^K3Bn  
return nFileLength; ka=EOiX.  
} 0Ba*"/U]t~  
O n/q&h5  
x u<oQBt  
//保存下载信息(文件指针位置) (baBi9<P=  
private void write_nPos() [%LIW%t|  
{ X:2)C-l?  
try{ M4}b l h#  
output = new DataOutputStream(new FileOutputStream(tmpFile)); BG/Q7s-?K  
output.writeInt(nStartPos.length); y?P4EVknM3  
for(int i=0;i<nStartPos.length;i++) &RB{0Qhx  
{ _jWGwO  
// output.writeLong(nPos); *N65B#  
output.writeLong(fileSplitterFetch.nStartPos); 7 MZ(tOR  
output.writeLong(fileSplitterFetch.nEndPos); N!lQ;o'  
} .dPy<6E  
output.close(); sD=iHO Am  
} Eg+ z(m$M  
catch(IOException e){e.printStackTrace ();} K#;EjR4H  
catch(Exception e){e.printStackTrace ();} AFdBf6/" i  
} Vw";< <0HZ  
|V-)3 #c  
Lj2Au_5  
//读取保存的下载信息(文件指针位置) W&=F<n`  
private void read_nPos() $N/"c$50,  
{ wOV}<.W  
try{ I?OnEw  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); Q@ghQGn#  
int nCount = input.readInt(); $s<bKju  
nStartPos = new long[nCount]; AQgagE^  
nEndPos = new long[nCount]; I><sK-3  
for(int i=0;i<nStartPos.length;i++) m {?uR.O  
{ I* 4g ;1x  
nStartPos = input.readLong(); M32Z3<  
nEndPos = input.readLong(); w,VUWja  
} p<8Ga.kiN  
input.close(); iM_Zn!|@\  
} L(`Rf0smt  
catch(IOException e){e.printStackTrace ();} chszP{-@X  
catch(Exception e){e.printStackTrace ();} &Xp<%[:  
} -_T@kg[0zB  
?bw1zYP  
I%tJLdL  
private void processErrorCode(int nErrorCode) VQ/Jz5^  
{ 8dCa@r&tz  
System.err.println("Error Code : " + nErrorCode); k|; [)gE  
} LgJUMR8vUO  
r8TNl@Z  
}gtkO&  
//停止文件下载 i1ss}JJp*  
public void siteStop() V[fcP;   
{ BkJNu_{m?  
bStop = true; D)GD9MJ  
for(int i=0;i<nStartPos.length;i++) +ieRpVg  
fileSplitterFetch.splitterStop(); &? z6f9*$  
lQl  
&vV_,$  
} ,#hx%$f}d  
} %Kc2n9W  
//负责部分文件的抓取 c~v(bK  
**FileSplitterFetch.java by@}T@^\  
*/ "FH03 9  
package NetFox; tY0C& u2  
<Kt;uu>  
CSNfLGA  
import java.io.*; MClvmv^  
import java.net.*; sY@x(qkIOc  
65AG# O5R  
L0EF CQ7  
public class FileSplitterFetch extends Thread { IrTMZG  
B,avI&7M;S  
?)mM]2%%  
String sURL; //File URL \zv?r :1t  
long nStartPos; //File Snippet Start Position (f>~+-IL  
long nEndPos; //File Snippet End Position |z]--h  
int nThreadID; //Thread's ID QTbv3#  
boolean bDownOver = false; //Downing is over /d-d8n  
boolean bStop = false; //Stop identical  >q^l  
FileAccessI fileAccessI = null; //File Access interface >Qold7 M  
L>{p>  
-Gn0TA2/C  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException RqE|h6/  
{ ~CQTPR  
this.sURL = sURL; 7FvtWE*  
this.nStartPos = nStart; BZ"+ ND9m_  
this.nEndPos = nEnd; 2#t35fU  
nThreadID = id; fFNwmH-jv  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 -$+`v<[r  
} a[A9(Ftn  
UCL aCt -  
9~6)u=4sS"  
public void run() V]qv,>  
{ ?R8wmE[w  
while(nStartPos < nEndPos && !bStop) 1:VbbOu->V  
{ i! DO  
|)+; d  
+c-?1j  
try{ ncCgc5uP  
URL url = new URL(sURL); uIb,n5  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); '980.  
httpConnection.setRequestProperty("User-Agent","NetFox"); 3r]N\c  
String sProperty = "bytes="+nStartPos+"-"; M8}t`q[-&  
httpConnection.setRequestProperty("RANGE",sProperty); W&Pp5KR  
Utility.log(sProperty); 0Z<&M|G  
M^3pJ=;5  
!i77v, (#|  
InputStream input = httpConnection.getInputStream(); l-G] jXu  
//logResponseHead(httpConnection); S=.7$PY  
k7\ ,N o}  
f!n0kXVu6U  
byte[] b = new byte[1024]; }Rx`uRx\  
int nRead; F|3iKK022  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ?OFl9%\ V  
{ ERQc1G]3Dd  
nStartPos += fileAccessI.write(b,0,nRead); @.SuHd  
//if(nThreadID == 1) xhmrep6+<  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 6 7{>x[  
} g7r_jj%ow  
#FQkwX'g  
 a }m>  
Utility.log("Thread " + nThreadID + " is over!"); gvl3NQQ%t  
bDownOver = true; MzudCMF  
//nPos = fileAccessI.write (b,0,nRead); 8BgHoQ*  
} p ! _\a  
catch(Exception e){e.printStackTrace ();} P/hV{@x  
} -IF3'VG  
} QaYUcma~n  
JX!@j3  
xG|T_|?  
//打印回应的头信息 U1!#TD)@  
public void logResponseHead(HttpURLConnection con) W-UMX',0zS  
{ 0`D` Je<t  
for(int i=1;;i++) UBZ37P  
{ 4`M7 3k0  
String header=con.getHeaderFieldKey(i); 8\H*Z2yF+  
if(header!=null) ^}PG*h|  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Ub_!~tb}?  
Utility.log(header+" : "+con.getHeaderField(header)); jqeR{yo&0b  
else 8uZM%7kI6+  
break; uz%<K(:Ov  
} H/?@UJ5m  
} =]swhF+l-  
1;8%\r[|5^  
l}jC$B`5  
public void splitterStop() g;n6hXq4  
{ h%*@82DKK  
bStop = true;  Z,Z4Sp  
} Nm.G,6<J  
9z9\pXFQ  
N R0"yJV>  
} w28&qNha  
_yN&+]c  
#q mv(VB4  
/* yRyUOTK  
**FileAccess.java FMNT0  
*//文件访问(定位,写) e\7AtlW"  
package NetFox; V=cJdF  
import java.io.*; .X](B~\!  
]H$Trf:L  
LuE0Hb"S8  
public class FileAccessI implements Serializable{ nQaryL  
?;xL]~Q~1  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 RE%25t|  
RandomAccessFile oSavedFile; gCL?{oVU  
long nPos; vKFEA7  
IDK~ (t  
R}E$SmFg  
public FileAccessI() throws IOException -SlAt$IJ  
{ O/b1^ Y   
this("",0); @=NTr  
} n3" @E<rW  
"%rzL.</  
' TO/i:{\  
public FileAccessI(String sName,long nPos) throws IOException lKBI3oYn  
{ E@J}(76VS  
oSavedFile = new RandomAccessFile(sName,"rw"); 9 K~X+N\  
this.nPos = nPos; .$U=ng j\t  
oSavedFile.seek(nPos); OD6dMql  
} u$rSM0CJ  
oEJxey]B7  
AvZO R  
public synchronized int write(byte[] b,int nStart,int nLen) W_bA.z T{  
{ r*kz`cJ  
int n = -1; qS/ 'Kyp_  
try{ eHc.#OA&  
oSavedFile.write(b,nStart,nLen); )CoJ9PO7  
n = nLen; q-r5zGI  
} jP31K{G?  
catch(IOException e) ow4|GLU^;  
{ V(=3K"j  
e.printStackTrace (); *(o^w'5  
} tpQ8 m(  
j)mi~i*U  
"Z#MR`;&29  
return n; Mi<}q@]e  
} { 4B7a6  
3^`.bm4 ^  
5 J 7XVe>  
} GXwQ )P5]  
GiKmB-HO  
M5`wfF,j  
/* &`}ACTY'P  
**SiteInfoBean.java -ze@~Z@  
*/ 6#Bg99c  
package NetFox; 4`p[t;q  
bJB* w  
ksV ^Y=]  
public class SiteInfoBean { Tl S 904'  
QuBaG<  
/ jN &VpDG  
private String sSiteURL; //Site's URL *]e 9/f  
private String sFilePath; //Saved File's Path $*;ke5Dm4  
private String sFileName; //Saved File's Name NBO&VYs|  
private int nSplitter; //Count of Splited Downloading File 24I~{Qy  
fYzZW  
x<>In"QV  
public SiteInfoBean() lt|UehJ F  
{//nSplitter的缺省值为5 j12khp?  
//default value of nSplitter is 5 _j?/O)M c  
this("","","",5); q&V=A[<rz  
} G;;iGN  
5uD'Kd$H  
ZZU"Q7`^  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) F}4jm,w  
{ IfpFsq:  
sSiteURL= sURL; pd oCV  
sFilePath = sPath; Zl7m:b2M  
sFileName = sName; 0 hS(9y40  
this.nSplitter = nSpiltter; YojYb]y+ j  
[(/IV+  
"hXB_73)V  
} :a y-2  
`KJ BQK  
q /^&si  
public String getSSiteURL() I~NQt^sg  
{ -,} ppTG  
return sSiteURL; ewv[nJD$  
} qY%{c-aMA  
*m`KY)b=l  
&#qy:  
public void setSSiteURL(String value) x)!NB99(tC  
{ a%)-iL X8&  
sSiteURL = value; ?#_]Lzn'  
} MYF6tZ*  
U#1 ,]a\  
9|RR;k[  
public String getSFilePath() w65D;9/;  
{ H| 1O>p&  
return sFilePath; Z}4 `y"By  
} :s`\jJ  
Ae 3:"  
1VC:o]$  
public void setSFilePath(String value) mo- Y %  
{ [p# }=&d  
sFilePath = value; %#,EqN  
} ds"q1  
Q`7.-di  
O6$d@r;EK]  
public String getSFileName() %wuD4PRK  
{ {@w!kl~8  
return sFileName; ~kW[d1'c  
} o7;#B)jWS  
Kt3 ]r:&J  
8RJ^e[?o(  
public void setSFileName(String value) y,QJy=?  
{ t\%gP@?  
sFileName = value; y}t1r |p  
} WVfwt.Y  
:7-2^7z)  
#N'W+M /  
public int getNSplitter() 7r4|>F  
{ -*T<^G;rK  
return nSplitter; HM(S}>  
} w`$M}oX(  
%}=:gF  
1SGLA"r  
public void setNSplitter(int nCount) [|!A3o  
{ wfXm(RYM  
nSplitter = nCount; at-+%e  
} k6?;D_dm  
} n$oHr  
',Q|g^rF]  
?\.aq p1B  
/* shAoib?Kw:  
**Utility.java {5, ]7=]  
*/ )Z0bMO<  
package NetFox; :ENdF `nC  
ZcLW8L  
EDf"1b{PX  
public class Utility { AYP*J  
9cwy;au  
e: aa  
public Utility() v{[:7]b_=  
{ Fb0r(vQ^  
GWvw<`4  
y`|86` Y  
} 5u89?-UD  
qTuQ]*[-  
//线程睡眠 !F|#TETrt  
public static void sleep(int nSecond) y k{8O.g  
{ Ump$N#  
try{ W Y]   
Thread.sleep(nSecond); QK`5KB(k'  
} -/'_XR@1  
catch(Exception e) 45aUz@  
{ DQ*T2*L  
e.printStackTrace (); =+z+`ot  
} ^tTASK  
} F!_8?=|  
bQlvb  
//日志 qbsmB8rh  
public static void log(String sMsg) rV_i|  
{ [`4  
System.err.println(sMsg); xk*&zAt  
} $Vp*,oRL  
!y\r.fm!A  
cTJi8f=g  
public static void log(int sMsg) TKe\Bi  
{ YT`,f*t  
System.err.println(sMsg); L~+/LV  
} 4^Y{ BS fF  
} 0H/)wy2ym  
CBr(a'3{Z  
2<FEn$n[  
/* dM=45$\q  
**TestMethod.java  mPL0s  
*/ HSk_'g(\0  
package NetFox; lHUd<kEC  
7 'q *(v  
({OQ JBC  
public class TestMethod { Uc;~q-??#  
:N^+!,i  
Yu$QL@  
public TestMethod() OUk"aAo  
{ ///xx/weblogic60b2_win.exe ?KtF!:_C  
try{ @V&c=8) 8  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); Rb!y(&>v  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); O joa3  
SiteFileFetch fileFetch = new SiteFileFetch(bean); ,gpZz$Ef(  
fileFetch.start(); 45?% D}  
} r3B}d*v  
catch(Exception e){e.printStackTrace ();} u4h0s1iI  
L^jjf8_  
U`aB&[=$  
} 5-hnk' ~  
PjD9D.  
#;yxn.</  
public static void main(String[] args) B[k=6EU8k  
{ uGv|!UQw  
new TestMethod(); 9=mc3m:Tb(  
} =C2KHNc  
} gYCr,-_i  
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