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http断点续传简单实现(java)

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/* lLS7K8;4W  
**SiteFileFetch.java wotw nE  
*/ (P-$tHt  
package NetFox; v4, Dt  
import java.io.*; HmbQL2  
import java.net.*; H`rd bE  
ipS:)4QFxJ  
V+t's*9o3  
public class SiteFileFetch extends Thread { m"wP]OQH*+  
_7'5IA  
sEi9<$~R@0  
SiteInfoBean siteInfoBean = null; //文件信息Bean xcH&B %;f  
long[] nStartPos; //开始位置 I5ZM U  
long[] nEndPos; //结束位置 }d%Fl}.Ez  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 t$rla _rbY  
long nFileLength; //文件长度 D THWL  
boolean bFirst = true; //是否第一次取文件 ]AX3ov6z9;  
boolean bStop = false; //停止标志  |^"0bu"  
File tmpFile; //文件下载的临时信息 |mcc?*%t8  
DataOutputStream output; //输出到文件的输出流 zpZfsn!  
y2=yh30L0E  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) aP#/%  
public SiteFileFetch(SiteInfoBean bean) throws IOException #\\|:`YV  
{ z, n[}Q#u  
siteInfoBean = bean; gj I>tz}  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); my#\(E+  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); PlCj<b1D:  
if(tmpFile.exists ()) ],Yy)<e.  
{ |qBcE  
bFirst = false; >T-4!ZvS\j  
read_nPos(); _PSOT5{  
} 5]n\E?V'L  
else |#'n VN.;  
{ ~0@fK<C)O  
nStartPos = new long[bean.getNSplitter()]; O&,8X-Ix  
nEndPos = new long[bean.getNSplitter()]; <T&v\DN  
} Fm*npK  
/Q_ Dd  
m"QDc[^Ge  
h J0U-m  
} (>NZYPw^3  
r-.>3J  
Je}0KW3G9L  
public void run() nv\K!wZI=b  
{ \`E^>6!]q  
//获得文件长度 A0:rn\$l3  
//分割文件 B9Hib1<8  
//实例FileSplitterFetch N1B$z3E *  
//启动FileSplitterFetch线程 9zY6hh**  
//等待子线程返回 X-#&]^d  
try{ w 5?D]u  
if(bFirst) #'0Yzh]qc  
{ 2_y]MXG+%  
nFileLength = getFileSize(); ambr}+}  
if(nFileLength == -1) is~2{:  
{ ,~DV0#"  
System.err.println("File Length is not known!"); .ws86stFSb  
} &BRa5`  
else if(nFileLength == -2) 6|~^P!&  
{ Id&e'  
System.err.println("File is not access!"); cqSXX++CS,  
} kguZAO6  
else :mW< E  
{ |<5F08]v  
for(int i=0;i<nStartPos.length;i++) P%gA` j  
{ /R&h#;l  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); WTJ{M$  
} o +7)cI  
for(int i=0;i<nEndPos.length-1;i++) x~vNUyEN)  
{ Fx|`0 LI+C  
nEndPos = nStartPos[i+1]; _DH^ K 9,9  
} ');vc~C  
nEndPos[nEndPos.length-1] = nFileLength; h<TZJCt  
} &lLfVa-l  
} 8-B7_GoJ+B  
 tH44\~  
v"W*@7<`S  
//启动子线程 p6R+t]oH  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; `Z8k#z'bN  
for(int i=0;i<nStartPos.length;i++) %^L{K[}  
{ owQ,op #  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), b5LToy:  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), sQac%.H;`U  
nStartPos,nEndPos,i); YrB-n  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); *LU/3H|}  
fileSplitterFetch.start(); eqsmv [  
} PXkpttIE]M  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), RYjK4xT?Y/  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); tP7<WGHd/  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", OtmDZ.t;`  
nEndPos = " + nFileLength); XFvl  
// fileSplitterFetch[nPos.length-1].start(); [I3Nu8  
HFZ'xp|3dn  
xdgAu  
//等待子线程结束 $_E.D>5^%7  
//int count = 0; 4,z|hY_*t  
//是否结束while循环 +tT"  
boolean breakWhile = false; b4i=%]v8  
9<.O=-1~  
{tUe(  
while(!bStop) C2"^YRN,  
{ }7[]d7  
write_nPos(); 8O9^g4?  
Utility.sleep(500); hm! J@  
breakWhile = true; U?le|tK  
iX]OF.:   
uBx\xeI  
for(int i=0;i<nStartPos.length;i++)  pE)NSZ  
{ L)J1yw  
if(!fileSplitterFetch.bDownOver) 2c 0;P #ol  
{ B[GC@]HE  
breakWhile = false; -je} PwT  
break; z7bJV/f  
} tfGs| x  
} "Zgwe,#  
if(breakWhile) x2"1,1%H7  
break; *v+l,z4n  
eV|N@  
]O"f%   
//count++; /=m AVA  
//if(count>4) |VWT4*K  
// siteStop(); [g/D<g5O  
} ='o3<}  
i"0Bc{cQ  
?l/6DT>e  
System.err.println("文件下载结束!"); "kyCY9) %  
} :S0!  
catch(Exception e){e.printStackTrace ();} q>2bkcGY#  
} g %f5hy  
noxJr/A]  
\Mg_Q$  
//获得文件长度 %;k Hnl  
public long getFileSize() lLTqk\8g  
{ 2F:qaz  
int nFileLength = -1; +twoUn{#  
try{ Ds">eNq  
URL url = new URL(siteInfoBean.getSSiteURL()); (4+P7Z,Nc  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); n^4R]9U  
httpConnection.setRequestProperty("User-Agent","NetFox"); lI=<lmM0|/  
p"ytt|H  
4`5yrC d  
int responseCode=httpConnection.getResponseCode(); ?uq`|1`  
if(responseCode>=400) |:1{B1sqA  
{ xak)YOLRV  
processErrorCode(responseCode); ^<CVQ8R7  
return -2; //-2 represent access is error 'Zu S  
} bqcCA9 1  
!{lH*  
B}iEhWO6  
String sHeader; @L3XBV2  
ODxZO3  
4nsJZo#S/  
for(int i=1;;i++) e2O6q05 ?Q  
{ l^lb ^"o  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j,k3]bP  
//Utility.log(in.readLine()); 32YbBGDN!f  
sHeader=httpConnection.getHeaderFieldKey(i); g_Z tDxz  
if(sHeader!=null) h@Q^&%w  
{ ~#pATPW@(  
if(sHeader.equals("Content-Length")) }D#: NlMp  
{ $H)^o!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); {~U3|_"[pX  
break; F` U~(>u'  
} %2}fW\% '  
} u:l-qD9=(  
else yix[zfQt0  
break; QKG3>lU  
} %k!CjW3  
} npdljLN  
catch(IOException e){e.printStackTrace ();} xa~]t<2  
catch(Exception e){e.printStackTrace ();} I^y<W%Et  
J usU5 e|  
m@Z#  
Utility.log(nFileLength); |b   
ETp?RWXX  
0pZvW  
return nFileLength; :7v'[b  
} QUrPV[JQ  
 1MN!  
~aob@(  
//保存下载信息(文件指针位置) -YA,Stc-  
private void write_nPos() aB ,-E>+  
{ Rf:.'/<^  
try{ HlGSt$woX  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 3!CUJs/W  
output.writeInt(nStartPos.length); 4b;Mb  
for(int i=0;i<nStartPos.length;i++) <tr]bCu}  
{ 7~7L5PRW  
// output.writeLong(nPos); Su#0 F0  
output.writeLong(fileSplitterFetch.nStartPos); w#"\*SKK  
output.writeLong(fileSplitterFetch.nEndPos); > i/jqT/  
} UL+Txc  
output.close(); |+#Zuq  
} p* >z:=  
catch(IOException e){e.printStackTrace ();} Tgdy;?  
catch(Exception e){e.printStackTrace ();} owAO&"C  
} y4^u&0}0$  
yXJhOCa  
vSgT36ZF  
//读取保存的下载信息(文件指针位置) 5 UEZpxnv  
private void read_nPos() At Wv9  
{ t-\+t<;  
try{ *6Wiq5M>.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1h,iWHC  
int nCount = input.readInt(); M(-)\~9T  
nStartPos = new long[nCount]; f"MID6  
nEndPos = new long[nCount]; fLDrit4_Q  
for(int i=0;i<nStartPos.length;i++) }icCp)b>v  
{ -,J<X\  
nStartPos = input.readLong(); KWJVc `  
nEndPos = input.readLong(); SDnl^a  
} +-izC%G  
input.close(); q}{E![ZTu  
} >*-%:ub  
catch(IOException e){e.printStackTrace ();} ? x)^f+:9|  
catch(Exception e){e.printStackTrace ();} )x.%PUA  
} ;blL\|ch;  
u?^V4 +V  
":]X r!e  
private void processErrorCode(int nErrorCode) ]Ry9{:  
{ "Y&I#&$b\  
System.err.println("Error Code : " + nErrorCode); s(,S~  
} sy&[Q{,4  
JF=R$!5  
"zEl2Xn28_  
//停止文件下载 $WA wMS,  
public void siteStop() RY-iFydPc  
{ G~9m,l+  
bStop = true; -cgO]q+Oq  
for(int i=0;i<nStartPos.length;i++) &^=Lr:I  
fileSplitterFetch.splitterStop(); ]!hjKu"  
#6 M] tr  
BA;r%?MRL  
} BQu |qr q  
} T.bFB+'E|  
//负责部分文件的抓取 {R1]tGOf  
**FileSplitterFetch.java ~D52b1f  
*/ ]H1mj#EWU  
package NetFox; OSu&vFKz  
-gn0@hS0  
+R'8$  
import java.io.*; {oQs*`=l>  
import java.net.*; Jh"[ug  
/!6'K  
85<k'>~L  
public class FileSplitterFetch extends Thread { Jqoo&T")  
JE.$]){  
LU3pCM{  
String sURL; //File URL 6 @f>  
long nStartPos; //File Snippet Start Position EP>u%]#  
long nEndPos; //File Snippet End Position fNN l1Vls  
int nThreadID; //Thread's ID j\}.GM'8  
boolean bDownOver = false; //Downing is over V U3RFl  
boolean bStop = false; //Stop identical $|$@?H>K  
FileAccessI fileAccessI = null; //File Access interface Xaz "!  
4.9qB  
}k-V(  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException $QJ3~mG2  
{ bT:u |/I  
this.sURL = sURL; TmgC {_  
this.nStartPos = nStart; e!u]l  
this.nEndPos = nEnd; ?2@^O=I  
nThreadID = id; \/Y(m4<P  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 %\'=Y/yP  
} vC]X>P5Px  
M9"Bx/  
Q 3WD!Z8y  
public void run() d) -(C1f  
{ VDxm|7  
while(nStartPos < nEndPos && !bStop) !j!w $  
{ 9< mMU:  
dL42)HP5  
,TBOEu."4  
try{ v :pT(0N  
URL url = new URL(sURL); b(K"CL\p  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); .@H:P  
httpConnection.setRequestProperty("User-Agent","NetFox"); \h ~_<)  
String sProperty = "bytes="+nStartPos+"-"; /-M:6  
httpConnection.setRequestProperty("RANGE",sProperty); OVLVsNg  
Utility.log(sProperty); /&gg].&2?  
Z`TfS+O6  
rPk|2l,E,3  
InputStream input = httpConnection.getInputStream(); * + T(i  
//logResponseHead(httpConnection); VEps|d3,,  
y##h(y  
[ycX)iM  
byte[] b = new byte[1024]; Ip8ml0oG  
int nRead; p?gm=b#  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) q1ysT.{p,  
{ !5,C"r  
nStartPos += fileAccessI.write(b,0,nRead); J 2O,wb)U  
//if(nThreadID == 1) &2ED<%hH`  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Us`=^\  
} 0)&!$@HW  
p]aEC+q  
%lCZ7z2o  
Utility.log("Thread " + nThreadID + " is over!"); s^u  Y   
bDownOver = true; ::Zo` vP  
//nPos = fileAccessI.write (b,0,nRead); D07M!U  
} 3Gs\Q{O:  
catch(Exception e){e.printStackTrace ();} R3B+vLGX  
} SVU>q:ab  
} %`]+sg[i  
xs= ~N  
"0eX/ rY%  
//打印回应的头信息 '5h` ="  
public void logResponseHead(HttpURLConnection con) Q}#Je.;  
{ ZvRa"j  
for(int i=1;;i++) 0F[ f%2j  
{  O3sV)  
String header=con.getHeaderFieldKey(i); 3)G~ud  
if(header!=null) kjYM&q  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); NQ{(G8x9  
Utility.log(header+" : "+con.getHeaderField(header)); MblRdj6  
else ?V6,>e_+  
break; K P]ar.  
} um,f!ho-U  
} <-I69`  
ggD T5hb  
svpQ.Q  
public void splitterStop() K<P d.:  
{ HzTmNm)  
bStop = true; ACyK#5E  
} K6DN>0sY  
&g|[/~dIr  
"3RFy i  
} `'1g>Ebk0  
5/"$ _7"{a  
y[m,t}gi  
/* Znb={hh  
**FileAccess.java A.>mk598  
*//文件访问(定位,写) kY)Vr3uGA  
package NetFox; J*;RL`  
import java.io.*; Y-ao yoNS  
T.da!!'B f  
l*l*5hA  
public class FileAccessI implements Serializable{ GRcPzneiz  
1_+ h"LE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 V,-we|"  
RandomAccessFile oSavedFile; |.k'?!  
long nPos; re*}a)iL  
s|\)Y*B`  
KQr+VQdq>  
public FileAccessI() throws IOException DhE-g<  
{ 9,?~dx  
this("",0); ,iV%{*p]  
} nXT`7  
Bve|+c6W  
p#$/{;yy  
public FileAccessI(String sName,long nPos) throws IOException ep6+YK:cn  
{ z$J m1l  
oSavedFile = new RandomAccessFile(sName,"rw"); G'JHimP2j  
this.nPos = nPos; DP{nvsF  
oSavedFile.seek(nPos); |^Iox0A  
} NzT &K7v  
sT?{  
EJn]C=_(  
public synchronized int write(byte[] b,int nStart,int nLen) h4]^~stI  
{ A4"TJZBg}  
int n = -1; q;68tEupR  
try{ AlQhKL}|s  
oSavedFile.write(b,nStart,nLen); &l+Qn'N  
n = nLen; l|.}>SfL^u  
} c,@Vz 7c  
catch(IOException e) CzBYH   
{ y-hTTd"{  
e.printStackTrace (); h`6 (Oo|  
} &qbEF3p^@  
T]\1gs41  
v6 5C j2ec  
return n; ~uhW~bT  
} ~:Rbd9IB  
) ^ En  
=f~<*wQ  
} Z:{| ?4  
RZHfT0*jL  
vaeQ}F  
/* naR<  
**SiteInfoBean.java #aX#gh}1  
*/ KkUK" Vc  
package NetFox; Z=&|__ +d  
'pt(  
1WtE] D  
public class SiteInfoBean { oL]uY5eZoe  
MnD}i&k[  
,8384'  
private String sSiteURL; //Site's URL :aOR@])>o  
private String sFilePath; //Saved File's Path $q\"d?n  
private String sFileName; //Saved File's Name d}O\:\}y  
private int nSplitter; //Count of Splited Downloading File S})f`X9_}  
uqcG3Pi  
_WNbuk0  
public SiteInfoBean() /Q st :q  
{//nSplitter的缺省值为5 k<1i.rh  
//default value of nSplitter is 5 o%'1=d3R1Q  
this("","","",5); K^!#;,0  
} G/JGb2I/7|  
^$'{:i  
N)mZ!K44  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) rfonM~3?'  
{ <Z.`X7]Uk  
sSiteURL= sURL; F`4W5~`  
sFilePath = sPath; Pyuul4(  
sFileName = sName; s={>{,E  
this.nSplitter = nSpiltter; =bh: U90y  
Y%/RGYKh  
(EcP'F*;;y  
} _=0Ja S>M.  
f2c <-}wR  
x=H{Rv  
public String getSSiteURL() h 8$.mQr  
{ Do(G;D`h+_  
return sSiteURL; ~ox}e(x y  
} &/[MWQ  
WzFXF{(  
Hx6O Dj[-  
public void setSSiteURL(String value) W^09tx/I  
{ E"*E[>  
sSiteURL = value; S$SCW<LuN  
} k(G6` dY  
X[Iy6qt  
1M`>;fjYa  
public String getSFilePath() u)h {"pP  
{ }eSy]r[J  
return sFilePath; egsP\ '  
} "yH?df24  
k% \;$u=%  
9+y&&;p  
public void setSFilePath(String value) wxB HlgK4z  
{ r3x;lICx-  
sFilePath = value; '?$@hqQn  
} FrMXf,}  
Oa:C'M b  
Z5'^Hj1,  
public String getSFileName() ?J6Ek*E#  
{ LS*L XC  
return sFileName; RNB -W%  
} %H?B5y  
9.xb-m7  
.4ww5k>  
public void setSFileName(String value) W2h*t"5W  
{ d>#',C#;  
sFileName = value; 7}qxWz  
} jh z*Y}MX  
*# <%04f  
{QG6ldI  
public int getNSplitter() mK TF@DED  
{ 7_36xpw  
return nSplitter; vy2<'V*y}  
} >lmqPuf  
fqbWD)L]  
\a0{9Xx F  
public void setNSplitter(int nCount) { #B/4  
{ r[):'ys,C  
nSplitter = nCount; A%EhRAy  
} ?v,c)  
} LV9R ]  
:icpPv  
5fs,UH  
/* Msvs98LvW  
**Utility.java U5ph4G  
*/ x xzUey  
package NetFox; wGMoh.GTh  
Q2oo\  
C&@'oLr  
public class Utility { dVq9'{[3  
3,Z;J5VL4!  
(Of`VT3ZOA  
public Utility() (' %Y3z;  
{ ekfa"X_  
9T2_2  
 0zr%8Q(Q  
} nT 4Ryld  
V@RdvQy  
//线程睡眠 F@z%y'5 Z*  
public static void sleep(int nSecond) %d-WQwJ  
{ w&}<b%l  
try{ w?3ww7yf`  
Thread.sleep(nSecond); Q<szH1-  
} Y]~-S  
catch(Exception e) IuFr:3(  
{ EBWM8~Nm#  
e.printStackTrace (); ]ZR` 6|"VO  
} |ggtb\W  
} _lT'nFe =Q  
7uUq+dp  
//日志 *E>R1bJ8  
public static void log(String sMsg) *\+oe+3  
{ 2>.b~q@  
System.err.println(sMsg); Uv?^qe0=  
} "7fEL:|j  
kwww5p ["  
F;/^5T3wI  
public static void log(int sMsg) qb=%W  
{ FP y}Wc*UA  
System.err.println(sMsg); s9Tn|Pm+!\  
} (-;(wCEE  
} ~[aV\r?  
toj5b;+4F  
qxyY2&  
/* jpXbFWgN  
**TestMethod.java -=lL{oB1  
*/ ]4')H;'y  
package NetFox; Bn.R,B0PL  
Dbx zqd  
gs.+|4dv  
public class TestMethod { < )_#6)z:  
wmMn1q0F  
,'<NyA><  
public TestMethod() Mj2Dat`p9  
{ ///xx/weblogic60b2_win.exe } nIYNeP?D  
try{ xIb{*)BUwc  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ]A\qI>,  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 5yJ~ q  
SiteFileFetch fileFetch = new SiteFileFetch(bean); cN2Pl%7  
fileFetch.start(); QYj 4D  
} ~U]%>Zf  
catch(Exception e){e.printStackTrace ();} c/F!cW{z^  
.'l3NV^{  
8t7r^[T  
} 9N2.:<so  
K0@bh/i/^  
64y9.PY  
public static void main(String[] args) o5+7Lt]  
{ c>r~pY~$  
new TestMethod(); 7bVKH[  
} JHg;2xm"<K  
} |<1A<fU8a  
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