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http断点续传简单实现(java)

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/* So'.QWzX  
**SiteFileFetch.java %&| uT  
*/ G7Sw\wW  
package NetFox; "cPg_-n  
import java.io.*; z+yIP ?s}(  
import java.net.*; C?T\5}h  
G+t:]\  
&Xqxuy ]J  
public class SiteFileFetch extends Thread { Xa?O)Bq.  
ng"=vmu  
?(R3%fU  
SiteInfoBean siteInfoBean = null; //文件信息Bean Es%f@$0uy  
long[] nStartPos; //开始位置 qul#)HI  
long[] nEndPos; //结束位置 dkZe.pv$j  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 >m,hna]RZ  
long nFileLength; //文件长度 |uqI}6h.  
boolean bFirst = true; //是否第一次取文件 9ziFjP+1  
boolean bStop = false; //停止标志 <78|~SKAV  
File tmpFile; //文件下载的临时信息 _wS=*-fT  
DataOutputStream output; //输出到文件的输出流 (^m] 7l  
0f.j W O  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) <ak[`]  
public SiteFileFetch(SiteInfoBean bean) throws IOException q!eE~O;A  
{ aQtd6L+ J  
siteInfoBean = bean; a3tcLd|7J  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); 89g a+#7  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); JfIXv  
if(tmpFile.exists ()) MK=oGzK  
{ 0lg$zi x(  
bFirst = false; H.@$#D  
read_nPos(); ~\jP+[>M'  
} V0>X2&.A  
else >8>!wi9U  
{ ,=P&{38\q  
nStartPos = new long[bean.getNSplitter()]; =GPXuo  
nEndPos = new long[bean.getNSplitter()]; 7"!b5(4=  
} b-sN#'TDg  
Pwl*5/l  
'|[V}K5m/f  
<m]0!ii  
} xR/CP.dg  
ctZ,qg*N  
m9DFnk<D  
public void run() }kqh[`:  
{ ,PTM'O@aU#  
//获得文件长度 * 9^8NY]  
//分割文件 ahg:mlaob  
//实例FileSplitterFetch 6]?mjG6  
//启动FileSplitterFetch线程 3' i6<  
//等待子线程返回 E1eGZ&&Gd  
try{ wtY)(k a  
if(bFirst) sFTAE1|  
{ EfrQ~`\  
nFileLength = getFileSize(); ,Vhve'=*2  
if(nFileLength == -1) ayy\7b  
{ ?e$&=FC0;  
System.err.println("File Length is not known!"); g X!>ef  
} L 0fe  
else if(nFileLength == -2) .B:ZyTI  
{ K381B5_h  
System.err.println("File is not access!"); J:yv82  
} ""0 Y^M2I  
else Rql/@j`JX  
{ ga 5Q  
for(int i=0;i<nStartPos.length;i++) 9\_AB.Z:  
{ /?'~`4!(  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); K ze?@*  
} fp' '+R[   
for(int i=0;i<nEndPos.length-1;i++) }=[p>3Dd  
{ nK1eh@a9Qv  
nEndPos = nStartPos[i+1]; 0K%okq|n  
} NP T-d  
nEndPos[nEndPos.length-1] = nFileLength; DM^0[3XuV5  
} R| ?Q&F_$  
} ~~W.]>f  
djdTh +>28  
WNGX`V,d  
//启动子线程 >Ku4Il+36  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; :?6HG_9X  
for(int i=0;i<nStartPos.length;i++) ~)U50. CH  
{ &Hb%Q! ^Kb  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "lh4Vg\7n  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),  J=` 8  
nStartPos,nEndPos,i); NN*L3yx  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); ; llPM`)  
fileSplitterFetch.start(); }?s-$@$R  
} 23gN;eD+m6  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), FEjO}lTK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); *7xcwj eP  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", oy^-?+   
nEndPos = " + nFileLength); $hhXsu=  
// fileSplitterFetch[nPos.length-1].start(); 0cS$S Mn{  
U>2KjZB  
9 C[~*,qx  
//等待子线程结束 GW,EyOE+~  
//int count = 0; NUV">i.(  
//是否结束while循环 n n7LL+h  
boolean breakWhile = false; Q,KNZxT,q  
6!\V|  
fDy*dp4z  
while(!bStop) uy {O   
{ 46>rvy.r  
write_nPos(); zPaubqB  
Utility.sleep(500); CvU$Fsb  
breakWhile = true; ?Y4 +3`\x  
tbS hSbj  
Cn~VJ,l g  
for(int i=0;i<nStartPos.length;i++) J@5iD  
{ YSP\+ZZ  
if(!fileSplitterFetch.bDownOver) ]Dq6XR  
{ !85bpQ.  
breakWhile = false; d{S'6*`D  
break; c4fH/-  
} cp`J ep<T  
} $${I[2 R)  
if(breakWhile) dc)%5fV\  
break; 7{ m>W!  
^*ZaqMA  
:uCwWv   
//count++; EO!,rB7I  
//if(count>4) t2d sYU/  
// siteStop(); sX1DbEjj[o  
} 9JA@m  
1-y8Hy_a2  
6>]_H(z7  
System.err.println("文件下载结束!"); [G}dPXD  
} wn[)/*(,$(  
catch(Exception e){e.printStackTrace ();} L$PbC!1  
} `+,?%W)  
L`nW&; w'  
5 A0]+)5E8  
//获得文件长度 j\ y!  
public long getFileSize() t% qep|  
{  =yod  
int nFileLength = -1; ^Q8yb*MN  
try{ UR'[?  
URL url = new URL(siteInfoBean.getSSiteURL()); u@_|4Bp,"  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); M/o?D <'  
httpConnection.setRequestProperty("User-Agent","NetFox"); BN9e S   
=8]`-(  
x=DxD&I!J  
int responseCode=httpConnection.getResponseCode(); Bp^LLH  
if(responseCode>=400) _lv{8vf1B  
{ vMz|'-rm$  
processErrorCode(responseCode); ZXnacc~s  
return -2; //-2 represent access is error u "0{) ,  
} al[^pPKZ  
i@rtt M  
Mq0MtC6-  
String sHeader; ._rPM>B?  
Qder8I  
mx9vjW fy  
for(int i=1;;i++) s@Q7F{z  
{ p"0#G&-  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1 uU$V =  
//Utility.log(in.readLine()); ?Bu*%+  
sHeader=httpConnection.getHeaderFieldKey(i); +R*DE5dz  
if(sHeader!=null) dj0%?g>  
{ 9`f@"%h  
if(sHeader.equals("Content-Length")) $FPq8$V  
{ (.#nl}fA  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); X_78;T)uA  
break; J 1w[gf]J  
} g  *,O  
} Kd oI  
else a>v *  
break; m"!SyN}&9?  
} d|R-K7 ~~  
} x;?8Zr  
catch(IOException e){e.printStackTrace ();} y.Z_\@  
catch(Exception e){e.printStackTrace ();} l= {Y[T&  
j@4MV^F2c  
_[[0rn$  
Utility.log(nFileLength); F3bTFFt  
7hk<{gnr  
^Laqq%PI  
return nFileLength; e|k]te  
} $OZ= L  
gAqK/9;  
63E6nW M  
//保存下载信息(文件指针位置) $#rkvG_w  
private void write_nPos() qm=U<'b^  
{ h3`}{ w  
try{ ,>B11Z}PH  
output = new DataOutputStream(new FileOutputStream(tmpFile)); Z )c\B  
output.writeInt(nStartPos.length); |^1g*f y?  
for(int i=0;i<nStartPos.length;i++) qm_l# u6  
{ rO#w(]   
// output.writeLong(nPos); jRg/N_2'2  
output.writeLong(fileSplitterFetch.nStartPos); i|{psA  
output.writeLong(fileSplitterFetch.nEndPos); ZLzc\>QX  
} [63\2{_^v  
output.close(); 4. R(`#f  
} HGYTh"R  
catch(IOException e){e.printStackTrace ();} >az~0PeEL  
catch(Exception e){e.printStackTrace ();} =][ )|n  
} RI*n]HNgy+  
5 tKgm/  
O|t>.<T?  
//读取保存的下载信息(文件指针位置) IR${a)  
private void read_nPos() aL:|Dr3SX  
{ D?dBm  
try{ !H\;X`W|~D  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); 1 iox0  
int nCount = input.readInt(); 3@" :&  
nStartPos = new long[nCount]; AUD) =a>  
nEndPos = new long[nCount]; @XJ7ff&  
for(int i=0;i<nStartPos.length;i++) n$2oM5<  
{ WK$\#>T  
nStartPos = input.readLong(); 3VLwY!2:  
nEndPos = input.readLong(); ?kR1T0lKkE  
} NFTv4$5d  
input.close(); rXW.F'=K6  
} a{xJ#_/6  
catch(IOException e){e.printStackTrace ();} qy'-'UlIr  
catch(Exception e){e.printStackTrace ();} K9zr]7;th  
} AE:(:U\  
iZG-ca  
YC1Bgz  
private void processErrorCode(int nErrorCode) \Vme\Ke*v)  
{ |tAkv  
System.err.println("Error Code : " + nErrorCode); )p>Cf_[.  
} v]M:HzP  
;U3:1hn  
yP7b))AW9  
//停止文件下载 kn}^oRT  
public void siteStop() GTLS0l)  
{ '1D $ ;  
bStop = true; 1 3 ]e< '  
for(int i=0;i<nStartPos.length;i++) ))AxU!*.  
fileSplitterFetch.splitterStop(); MiZ<v/L2  
ow'G&<0b  
HrE,K\^  
} )n)AmNpq   
} X{x(p  
//负责部分文件的抓取 ;h1hz^Wq  
**FileSplitterFetch.java  +rv##Z  
*/ }<~(9_+  
package NetFox; <%YW/k"o  
`<g]p-=":  
PPl o0R  
import java.io.*; T'}kCnp  
import java.net.*; |fKT@2(  
^ ##j {h7  
a]*{!V{$i  
public class FileSplitterFetch extends Thread { x_~_/&X5  
WOn<JCh]  
curYD~7  
String sURL; //File URL oaQW~R`_  
long nStartPos; //File Snippet Start Position oz=V|7,  
long nEndPos; //File Snippet End Position )Lz =[e  
int nThreadID; //Thread's ID xS UpVK  
boolean bDownOver = false; //Downing is over 2V]a+Cgk  
boolean bStop = false; //Stop identical \i+AMduAo  
FileAccessI fileAccessI = null; //File Access interface EPJ>@A>;D  
`V9bd}M%~;  
H<|}p Z  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException (-$5YKm  
{ bVz<8b6h'-  
this.sURL = sURL; +c/!R|h=S  
this.nStartPos = nStart; 693"Pg8b  
this.nEndPos = nEnd; 2->Lz  
nThreadID = id; 8 SU0q9X.  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 0uD3a-J  
} 'Y @yW3K  
S(CkA\[rz  
SZXSVz0j  
public void run() 6:wk=#w  
{ rmggP(  
while(nStartPos < nEndPos && !bStop) 2pmj*Y3"8  
{ K&&T:'=/  
3ibQbk  
{X<g93  
try{ j5DCc,s  
URL url = new URL(sURL); qeFaY74S  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 8o+:|V~X  
httpConnection.setRequestProperty("User-Agent","NetFox"); 7HVENj_b+M  
String sProperty = "bytes="+nStartPos+"-"; 8?8V;   
httpConnection.setRequestProperty("RANGE",sProperty); <lR:^M[v5<  
Utility.log(sProperty); a>l,H#w*vW  
Tv1oy%dK  
sSfP.R  
InputStream input = httpConnection.getInputStream(); L~f~XgQ  
//logResponseHead(httpConnection); Dl.UbH }=  
a& 0g0n6  
pq r_{  
byte[] b = new byte[1024]; c BqbbZyUk  
int nRead; d BB?A~  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) c/ImK`:)4a  
{ cz,CL/rno  
nStartPos += fileAccessI.write(b,0,nRead); mxZ+r#|di  
//if(nThreadID == 1) 842v^ 2  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); q]yw",muT  
} !U:&8Le  
)C"ixZ>2xQ  
sCw>J#@2>  
Utility.log("Thread " + nThreadID + " is over!"); 7k,BE2]"  
bDownOver = true; #w%-IhP  
//nPos = fileAccessI.write (b,0,nRead); vE,^K6q0`  
} S`YT"|~  
catch(Exception e){e.printStackTrace ();} Csy$1;"A  
} @5wc 3y  
} _cJ)v/]  
N$Ad9W?T  
5.ab/uk;M  
//打印回应的头信息 QY4;qA  
public void logResponseHead(HttpURLConnection con) &k,DAx`rN;  
{ ECi;o1hda  
for(int i=1;;i++) 7w2$?k',-  
{ V-7l+C5  
String header=con.getHeaderFieldKey(i); uvJHkAi  
if(header!=null) tz2=l.1  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); [ KgO:},c  
Utility.log(header+" : "+con.getHeaderField(header)); Z[w}PN,xV  
else d)V8FX,t  
break; uWKmINjv'  
} ;<m*ASM.3  
} .]h/M,xg  
u; KM[FmK  
LDEc}XXb  
public void splitterStop() ~b*]jZwT  
{ /0qbRk i  
bStop = true; YFS6YA  
} riOaqV  
MvZa;B  
L,.~VNy-  
} jZ-s6r2=  
q/zU'7%@  
$%cHplQz5  
/* i,^3aZwJ'  
**FileAccess.java 6\I^]\YO  
*//文件访问(定位,写) $adZ|Q\  
package NetFox; {|>Wwa2e  
import java.io.*; XQn1B3k+  
N,K/Ya)1  
VQqBo~  
public class FileAccessI implements Serializable{ G\ F>*  
ssLswb  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 >w<w*pC  
RandomAccessFile oSavedFile; @%x2d1FS  
long nPos; nS3Aadm  
d/yF}%0QI  
NjZ~b/  
public FileAccessI() throws IOException ^wWbW&<Tg  
{ ws9IO ?|&G  
this("",0); X uE: dL?  
} 1|4,jm$  
3%5YUG@  
(eU4{X7  
public FileAccessI(String sName,long nPos) throws IOException xE@/8h  
{ So!=uYX  
oSavedFile = new RandomAccessFile(sName,"rw"); 2`riI*fQ  
this.nPos = nPos; Wgh@XB  
oSavedFile.seek(nPos); WtZI1`\qe  
} 1N(1h D  
8u~  
:p}8#rb  
public synchronized int write(byte[] b,int nStart,int nLen) MuOKauYa  
{ 3%?tUt  
int n = -1; }~+,x#  
try{ #at`7#K@  
oSavedFile.write(b,nStart,nLen); T 'c39  
n = nLen; B2j1G JEO  
} -c]AS[(  
catch(IOException e) 9x@|%4Zm"  
{ s*la`(x  
e.printStackTrace (); l[:Aq&[o3  
} >-N(o2j3  
M{5AQzvs  
~x8nC%qPvq  
return n; pAatv;Ex  
}  "&k(lQ4  
#PD6LO  
<9ucpV  
} k2v:F  
:1UMA@HP  
8lpAe0p(Z  
/* ;_"|#  
**SiteInfoBean.java ?nW>' z  
*/ T#-;>@a}  
package NetFox; la+Cra&xL  
mF\!~ag|  
a)ry}E =f  
public class SiteInfoBean { 4{F1GW  
Kb(11$U  
TC/c5:)]  
private String sSiteURL; //Site's URL =D$ED^W  
private String sFilePath; //Saved File's Path D BHy%i  
private String sFileName; //Saved File's Name {7goYzQsi%  
private int nSplitter; //Count of Splited Downloading File 4Wiy2  
<v0`r2^S{-  
RX>P-vp  
public SiteInfoBean() 0uDDaFS  
{//nSplitter的缺省值为5 #gV n7wq  
//default value of nSplitter is 5 I2*rtVAP'j  
this("","","",5); zw+aZDcV(  
} q_.fVn:!  
d:';s~  
sRD fA4/TF  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) RJ3oI+gI  
{ .^{%hc*w4  
sSiteURL= sURL; WChP,hw  
sFilePath = sPath; hNN[djR  
sFileName = sName; /dYv@OU?  
this.nSplitter = nSpiltter; l@B9}Icq  
V,_m>$Mo  
) 6)bI.BY  
} W\kli';jyC  
y,nmPX?]n  
VQla.Y  
public String getSSiteURL() V_SH90@)+  
{ z/{X{+Z  
return sSiteURL; 2DCQ5XewYe  
} 4MS<t FH)  
C")genMH  
)cJ>&g4]  
public void setSSiteURL(String value) vt#;j;liG  
{ tNT Sy =  
sSiteURL = value; YGyv)\  
} ps 3 )d  
3 39q%j$  
bGWfMu=n  
public String getSFilePath() hN'])[+V  
{ Tsg9,/vXM  
return sFilePath; )SmnLvL  
} ^OY]Y+S`Ox  
+%W8Juu  
~(d {j}M>  
public void setSFilePath(String value) 1/Ts .\K3  
{ rz"$zc.)  
sFilePath = value; 5YD~l(,S1]  
} +Dy^4p?o  
iT-coI  
*V6| FU  
public String getSFileName() '{d@Gc6.  
{ r9 @=d  
return sFileName; EraGG"+  
} dgw.OXa  
y'_8b=*  
X .t4;  
public void setSFileName(String value) q?(] Y*  
{ Yb+A{`  
sFileName = value; 3%Y:+%VE  
} @z@%vr=vX  
D!&(#Vl _  
P"vrYom  
public int getNSplitter() k]@]a  
{ A;TP~xq\  
return nSplitter; Nwi|>'\C  
} yn62NyK  
lgOAc,  
j<<d A[X  
public void setNSplitter(int nCount) FO2e7p^Q  
{ vQEV,d1  
nSplitter = nCount; Tz]R}DKB&  
} -* ,CMw  
} $O%{l.-O  
nYyhQX~]B  
rpT.n-H>%A  
/* L80(9Y^xn  
**Utility.java ~Bzzu % S  
*/ p>B2bv+L  
package NetFox; 8 t5kou]h  
11=$] K>  
'X?xn@?  
public class Utility { xl\Kj2^  
$m4-^=  
x)::^'74  
public Utility() ~K;QdV=YX  
{ ":Dm/g  
iQ)ydY a  
;m(iKwDt  
} sl]< A[jR  
Y9+_MxC"  
//线程睡眠 WTvUz.Et  
public static void sleep(int nSecond) 4yl{:!la  
{ i>F=XE  
try{ 3P cVE\GN  
Thread.sleep(nSecond); }|P3(*S  
} .hl_zc#  
catch(Exception e) bNea5u##  
{ Aedf (L7\  
e.printStackTrace (); xVm-4gB  
} _;1{feR_  
} d?2V2`6  
Y %JQ  
//日志 V'vR(Wx  
public static void log(String sMsg) AcH-TIgM/  
{ H9cPtP~a)  
System.err.println(sMsg); @]=40Yj~w  
} WgtLKRZ\  
$]2)r[eA)  
Y2H-D{a27  
public static void log(int sMsg) r\Nfq(w  
{ CXlbtpK2k  
System.err.println(sMsg); qkb'@f=  
} NX @FUct;  
} PMzPj,  
(`tRJWbdz  
^#/FkEt7bp  
/* %MHb  
**TestMethod.java U&5* >fd=  
*/ Kgbm/L0XR*  
package NetFox; XjX  
/)P}[Q4  
AYts &+  
public class TestMethod { isQ(O  
'YL[s  
FwCb$yE#M  
public TestMethod() *3GV9'-P  
{ ///xx/weblogic60b2_win.exe (f#(B2j  
try{ =*mT{q@  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); ~ Z\:Nx  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); U ZM #O  
SiteFileFetch fileFetch = new SiteFileFetch(bean); j|eA*UE  
fileFetch.start(); *r7v Dc  
} 1\.$=N  
catch(Exception e){e.printStackTrace ();} x$Dq0FX!%_  
;a:H-iC  
u^80NR  
} tdy2ZPVtTV  
mDB  
V>Wk\'h  
public static void main(String[] args) \/a6h   
{ r* *zjv>  
new TestMethod(); M^FY6TT4O  
} o96C^y{~S  
} "W|A^@r}  
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