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http断点续传简单实现(java)

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/* {Z?!*Ow  
**SiteFileFetch.java ?q,x?`|(8  
*/ WLh_b)V|  
package NetFox; LoCxoAg  
import java.io.*; "R9kF-  
import java.net.*; N@d4)  
in+`zfUJ9  
{?L}qV  
public class SiteFileFetch extends Thread { YYM  
(U.&[B  
O0$ijJa|  
SiteInfoBean siteInfoBean = null; //文件信息Bean k2+Z7#2n  
long[] nStartPos; //开始位置 }<Me%`x"  
long[] nEndPos; //结束位置 n--`zx-['  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 RgRcW5VxK  
long nFileLength; //文件长度 X*Q7Yu  
boolean bFirst = true; //是否第一次取文件 HE,wEKp  
boolean bStop = false; //停止标志 6)bfd^JYn  
File tmpFile; //文件下载的临时信息 D 3HB`{  
DataOutputStream output; //输出到文件的输出流 >=Rb:#UM  
Ys3C'Gc  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) n&V(c&C  
public SiteFileFetch(SiteInfoBean bean) throws IOException dF?pEet?2  
{ 4@W.{|2~  
siteInfoBean = bean; .ZJh-cd  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); d z\b]H]  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); Wex4>J<`/  
if(tmpFile.exists ()) ypifXO;m7  
{ iH$N HfH  
bFirst = false; i*; V4zh  
read_nPos(); dJ;;l7":~  
} 1%:A9%O)t  
else gSv<.fD"  
{ ]E3g8?L  
nStartPos = new long[bean.getNSplitter()]; ;kFp)*i  
nEndPos = new long[bean.getNSplitter()]; pKJ[e@E^  
} SwL\=nq+~  
(J;?eeP  
50Jr(OeU<  
F3f>pK5  
} Bh.'%[',  
h7w<.zwu t  
U!`'Qw;  
public void run() ]fc:CR  
{ q>X:z0H  
//获得文件长度 tsa6: D  
//分割文件 |% kK?!e+-  
//实例FileSplitterFetch Q:LuRE!t  
//启动FileSplitterFetch线程 Umd!j,  
//等待子线程返回 x SUR<  
try{ |UaI i^  
if(bFirst) rTJWftH!  
{ V cL  
nFileLength = getFileSize(); R.QcXz?d  
if(nFileLength == -1) ?t"PawBWE  
{ 3HiW1*5W  
System.err.println("File Length is not known!"); x?F{=\z/o  
} p?h;Sv/  
else if(nFileLength == -2) ;|%r!!#-t  
{ d"cfSH;h  
System.err.println("File is not access!");  (M=Br  
} >fdN`W }M  
else O*PHo_&G  
{ ^ Q}1&w%  
for(int i=0;i<nStartPos.length;i++) h ^c'L=dR  
{ Qi}LV"&L  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); ][mc^eI0s|  
} lyPXlt  
for(int i=0;i<nEndPos.length-1;i++) W7 E-j+2  
{ }:irjeI,  
nEndPos = nStartPos[i+1]; pWp2{G^XB  
} M}<=~/k`j  
nEndPos[nEndPos.length-1] = nFileLength; +u2Co_FJ&  
} D^~g q`/)  
}  {MtB!x  
^`7t@G$ D  
t<7WM'2<y  
//启动子线程 7 AiCQWf9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; V Y3{1Dlf  
for(int i=0;i<nStartPos.length;i++) Yp)U'8{h c  
{ 00p 7sZU^  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), Ed-gYL^<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), w;(gi  
nStartPos,nEndPos,i); {|%O)fr,  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Dfo9jYPf  
fileSplitterFetch.start(); C"{on%  
} (D{}1sZBQ  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), l_%~X 9"  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); $^!w`>0C  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", cn0Fz"d  
nEndPos = " + nFileLength); ?X1#b2s  
// fileSplitterFetch[nPos.length-1].start(); iQF}x&a<  
e2fct|'  
B@=<'/S\7  
//等待子线程结束 AIyv;}5  
//int count = 0; &^H "T6  
//是否结束while循环 h~@+M5r,  
boolean breakWhile = false; d/&|%Z r  
 m5pVt 4  
w-$w  
while(!bStop) *PEuaRDN  
{ o0L#39`' g  
write_nPos(); A]9JbNV  
Utility.sleep(500); :ct+.#  
breakWhile = true; j1 <1D@UO  
dWy1=UQfP  
Z]f2&  
for(int i=0;i<nStartPos.length;i++) L'Zud,JKg  
{ bEKLameKv  
if(!fileSplitterFetch.bDownOver) ^j %UZ  
{ Oy&'zigJ  
breakWhile = false; q#`^EqtUF  
break; W wha?W>  
} I={{VQ  
} F21[r!3  
if(breakWhile) Z L</  
break; r<v%Zp  
O:)IRB3  
gpWS_Dw9  
//count++; [R>   
//if(count>4) ^mpB\D)q  
// siteStop(); .}N^AO=  
} =fG8YZ(  
PNgMLQI6  
ai4^NJn  
System.err.println("文件下载结束!"); l`&6W?C  
} c5e\ckqm^  
catch(Exception e){e.printStackTrace ();} [r8 d+  
} MF}Lv1/[-J  
>EtP^Lu~f_  
lg >AWTW[  
//获得文件长度 lM*O+k  
public long getFileSize() `uA&w}(G  
{ Nh9!lBm*]  
int nFileLength = -1; =bWq 3aP)P  
try{ }!V<"d,!  
URL url = new URL(siteInfoBean.getSSiteURL()); )c/y07er  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); )`mF.87b&h  
httpConnection.setRequestProperty("User-Agent","NetFox"); o$VH,2 QF  
>;v0zE  
zI!R-Nb  
int responseCode=httpConnection.getResponseCode(); (H+[^(3d2  
if(responseCode>=400) +c`C9RXk  
{ ~4MjJKzA  
processErrorCode(responseCode); m 1i+{((  
return -2; //-2 represent access is error yQ{_\t1Wd  
} R"gm]SQ/  
P &0cF{  
X-#mv|3  
String sHeader; lO> 7`2x=F  
 /kU@S  
gsWlTI  
for(int i=1;;i++) -_DiD^UcXn  
{ ;}~Bv<#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); Z4ov  
//Utility.log(in.readLine()); So%1RY{ )  
sHeader=httpConnection.getHeaderFieldKey(i); ' ,`4 U F  
if(sHeader!=null) &W+G{W{3  
{ G!Oq>7  
if(sHeader.equals("Content-Length")) :TYzzl43  
{ h_G|.7!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); 9~'Ip7X,!  
break; 8/?uU]#Q  
} }|"*"kxi!  
} )^S^s >3  
else b[o"Uq@8?  
break; :YXQ9/iRr  
} Qfu*F}  
} ioa_AG6B  
catch(IOException e){e.printStackTrace ();} <VR&= YJ  
catch(Exception e){e.printStackTrace ();} '3UIriY6  
dzNaow*0&V  
,tF" 4|#  
Utility.log(nFileLength); ^%$W S,  
u|>U`[Zpj  
nQ!#G(_nO  
return nFileLength; MQH8Q$5D  
} O\F^@;] F6  
*Gh8nQbh  
1qKxg  
//保存下载信息(文件指针位置) k>;r9^D  
private void write_nPos() i -s?"Fk  
{ Doc'7P  
try{ f9XO9N,hE:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); :G=1$gb  
output.writeInt(nStartPos.length); b;`#Sea  
for(int i=0;i<nStartPos.length;i++) VE"0 VB.  
{ Y1_6\zpA  
// output.writeLong(nPos); lPQ Ut!xI  
output.writeLong(fileSplitterFetch.nStartPos); VfC[U)w*vm  
output.writeLong(fileSplitterFetch.nEndPos); .y_bV=  
} $CwTNm?  
output.close(); `{Di*  
} p9}c6{Wp  
catch(IOException e){e.printStackTrace ();} $17 v,  
catch(Exception e){e.printStackTrace ();} 4U a~*58  
} ="w8U'  
}V#9tWW  
h:Mn$VR,  
//读取保存的下载信息(文件指针位置) p C2c(4  
private void read_nPos() ^@LhUs>3  
{ \ NSw<.  
try{ ~v(M6dz~vk  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); RQ)!KlY  
int nCount = input.readInt(); IfmIX+t?  
nStartPos = new long[nCount]; M3;v3 }z<-  
nEndPos = new long[nCount]; ? ]:EmP  
for(int i=0;i<nStartPos.length;i++) I;.! hV>E  
{ ;/^]|  
nStartPos = input.readLong(); ?)o4 Kt'h  
nEndPos = input.readLong(); t k/K0u  
} ny_ kr`$42  
input.close(); {p*hNi)0  
} nK%/tdq  
catch(IOException e){e.printStackTrace ();} GE8D3V;*V  
catch(Exception e){e.printStackTrace ();} {L-aXe{  
} b}?@syy8  
Gp3nR<+  
0m YZ7S5g  
private void processErrorCode(int nErrorCode) o`T<}z26  
{ + yP[(b/  
System.err.println("Error Code : " + nErrorCode); 8&A|)ur4  
} 3|'#n[3  
07LL)v~  
W/ZahPPq  
//停止文件下载 > ?{iv1  
public void siteStop() N7HbOLpM  
{ Vh.;p.!e  
bStop = true; OxHw1k  
for(int i=0;i<nStartPos.length;i++) ;GgQ@s@  
fileSplitterFetch.splitterStop(); 2*FWIHyf  
u388Wj   
gQpD]p%k  
} Dss/>! mN  
} zEPx  
//负责部分文件的抓取 HHIUl,P  
**FileSplitterFetch.java <j1d~XU}  
*/ l;{N/cS  
package NetFox; NtA|#"^  
$6&GAJe  
z Jo#3  
import java.io.*; <E7Vbb9*  
import java.net.*; j zmSFKg*  
C`th^dqBV  
B:A1W{l  
public class FileSplitterFetch extends Thread { k.=S+#"}  
(|a$N.e&K  
x+*L5$;h  
String sURL; //File URL X v7U<q  
long nStartPos; //File Snippet Start Position Puth8$  
long nEndPos; //File Snippet End Position gcW{]0%L^  
int nThreadID; //Thread's ID .t^UK#@#4  
boolean bDownOver = false; //Downing is over c]aK N  
boolean bStop = false; //Stop identical ;/)Mcx]n  
FileAccessI fileAccessI = null; //File Access interface  IB.'4B7  
[;IDTo!<>  
T?]kF-   
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException #-gGsj;F  
{ QC\g%MVG  
this.sURL = sURL; rPo\Dz  
this.nStartPos = nStart; TA@tRGP>  
this.nEndPos = nEnd; )(?UA$"  
nThreadID = id; H?=pWB  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 '[=yfh   
} srChY&h?<  
ll<9f)  
L%o65  
public void run() Lr24bv\  
{ .y;\puNq  
while(nStartPos < nEndPos && !bStop) 9OQ0Yc!3  
{ ]lB3qEn<  
.X LV:6  
WDoKbTv  
try{ -M>K4*%K  
URL url = new URL(sURL); mS)|6=Y  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); J^g,jBk  
httpConnection.setRequestProperty("User-Agent","NetFox"); &` 00/p  
String sProperty = "bytes="+nStartPos+"-"; =_?pOq  
httpConnection.setRequestProperty("RANGE",sProperty); ,2 g M-  
Utility.log(sProperty); ]4 K1%ZV  
.n)!ZN  
az \<sWb#  
InputStream input = httpConnection.getInputStream(); h[-d1bKwS  
//logResponseHead(httpConnection); =mi:<q  
b5n]Gp  
].k+Nzf_  
byte[] b = new byte[1024]; z3vsz  
int nRead; MKVfy:g%So  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) x#:BE  
{ ni"$[8U  
nStartPos += fileAccessI.write(b,0,nRead); tkdBlG]!  
//if(nThreadID == 1) e$ XY\{  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 22al  
} B \_d5WJ<  
Hn#GS9d_?  
'Ffy8z{&3  
Utility.log("Thread " + nThreadID + " is over!"); OZ>)sL  
bDownOver = true; j5,^9'  
//nPos = fileAccessI.write (b,0,nRead); dK J@{d  
} t> x-1vf%  
catch(Exception e){e.printStackTrace ();} l?o-!M{  
} !Ig|m+  
} ##EB; Y  
v ]/OAH6D  
)y%jLiQv  
//打印回应的头信息 ]< s\V-y  
public void logResponseHead(HttpURLConnection con) R%Ui6dCLo  
{ `FzYvd"N  
for(int i=1;;i++) d4y9AE@k  
{ FUyB"-<  
String header=con.getHeaderFieldKey(i); s.R-<Y 3  
if(header!=null) 68koQgI[^  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); |b$>68:  
Utility.log(header+" : "+con.getHeaderField(header)); F}6DB*  
else wDT>">&d  
break; Z{,GZT  
} 3wN?|N  
} Yo~LckFF  
n) _dH/"  
;t;Y.*&=S  
public void splitterStop() PJxak3  
{ VxkCK02k  
bStop = true; Z>(r9 R3{  
} z.2r@Psk  
(|0.m8D~D  
E ;BPN  
} sJ))<,e5I  
[K cki+  
V>b2b5QAH,  
/* }J ei$0x  
**FileAccess.java '%zN  
*//文件访问(定位,写) W>5vRwx00  
package NetFox; ,hpH!J'5f/  
import java.io.*; e2]4a3  
8)^B32  
F_A%8)N  
public class FileAccessI implements Serializable{ h4hN1<ky\  
gk!E$NyE  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 Jv_.itc  
RandomAccessFile oSavedFile; C5O5S:|'  
long nPos; w5F4"nl#O}  
./'~];&  
FAQr~G}  
public FileAccessI() throws IOException .]W ;2G  
{ {]wIM^$6+  
this("",0); ~L- 0~  
} A}t%;V2  
NFk}3w:  
[##`U m  
public FileAccessI(String sName,long nPos) throws IOException 403[oOj  
{ YBb)/ZghY  
oSavedFile = new RandomAccessFile(sName,"rw"); #O2wyG)oU  
this.nPos = nPos; [8>z#*B  
oSavedFile.seek(nPos); BdN8 ^W  
} ?e F@Q !h  
)v[XmJ>H~o  
8F#osN  
public synchronized int write(byte[] b,int nStart,int nLen) 63W{U/*aao  
{ bGbqfO`  
int n = -1; _f cS>/<a  
try{ "j{i,&Y$_  
oSavedFile.write(b,nStart,nLen); nz4<pvC,*  
n = nLen; *IC^IC:  
} >[ eW">:>K  
catch(IOException e) ')B =|T)  
{ >T<6fpXuk2  
e.printStackTrace (); \|CPR6I  
} YEzU{J  
6cJ<9i &  
` ^DjEdUN  
return n; rwiw Rh  
}  %BUEX  
_ Yfmxn8V  
QE|`&~sme  
} S_J,[#&  
|xn#\epy@  
G6ayMw]OF  
/* m#tpbFAsc  
**SiteInfoBean.java >lrhHU  
*/ GL1'Zo  
package NetFox; JPEIT  
R{HV]o|qk  
}91*4@B7  
public class SiteInfoBean { AXs=1  e  
5iVQc-m&  
$9 K(F~/  
private String sSiteURL; //Site's URL pz{'1\_+9  
private String sFilePath; //Saved File's Path )zU:  
private String sFileName; //Saved File's Name ]*qU+&  
private int nSplitter; //Count of Splited Downloading File axmsrj W#  
7paUpQit  
`ncNEHh7K  
public SiteInfoBean() OTj,O77k  
{//nSplitter的缺省值为5 ._?V%/  
//default value of nSplitter is 5 %SAw;ZtQ:  
this("","","",5); `Oq M8U @  
} ;j{7!GeKa  
YTK^ijmU6x  
MaO"#{i  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) gH[,Xx?BN!  
{ Ojq]HM6f  
sSiteURL= sURL; zJ+3g!  
sFilePath = sPath; mzWP8Hlw  
sFileName = sName; \<~}o I  
this.nSplitter = nSpiltter; N2BI_,hI1  
Z|G/^DK!  
Us,)]W.S  
} t2- ^-g6  
 FZ F @  
[#Y' dFQ  
public String getSSiteURL() ciudRK63M  
{ `5q ;ssu  
return sSiteURL; yEq#Dr  
} *^] ~RhjB  
8TE>IPjm  
{CtR+4KD  
public void setSSiteURL(String value) d|XmasGN  
{ "xe=N  
sSiteURL = value; Mo D?2J  
} V|'1tB=;*1  
!nd*W"_gQ/  
>O#grDXb  
public String getSFilePath() 24u x  
{ iXFP5a>|  
return sFilePath; c pk^!@c  
} 9'nH2,_  
)0k']g5  
n2 {SV  
public void setSFilePath(String value) Pao%pA.<  
{ 2C$R4:Ssw)  
sFilePath = value; ?P/AC$:|I  
} 6BocGo({  
o%`Xa#*Ly  
im]g(#GnKh  
public String getSFileName() +pf5\#l?  
{ 6?qDdVR~]  
return sFileName; #DFV=:|~  
} <@G8ni  
rv>^TR*,!  
BQ/PGY>  
public void setSFileName(String value) \L # INP4~  
{ S{#cD1>.  
sFileName = value; }^-<k0A4?  
} 8 Ti G3  
P:C2G(V1AR  
w8Vw1wW  
public int getNSplitter() bc I']WgB-  
{ Hp Vjee  
return nSplitter; $g10vF3  
} D\1k.tI  
+*}{`L- :  
5GQLd  
public void setNSplitter(int nCount) e5?PkFV^a1  
{ a.@qGsIH  
nSplitter = nCount; :7g=b%;  
} T6#CK  
} WC,+Cn e  
?wb+L  
X^@ I].  
/* rJJ[X4$  
**Utility.java vUA0FoOp  
*/ Sv'y e  
package NetFox; 5D Y\:AF  
W_`A"WdT.  
l@JSK ;  
public class Utility { lFSe?X^  
h3* x[W  
\4d.sy0&>-  
public Utility() 0d^Z uTN  
{ ({^9<Us  
e>}}:Ud  
!#2=\LUC  
} ?GA&f2]a  
ORN6vX(1  
//线程睡眠 +7V{ABfGl  
public static void sleep(int nSecond) zYY$D.  
{ *sw7niw  
try{ L';MP^  
Thread.sleep(nSecond); CZ<~3bEF  
} &HW1mNF9  
catch(Exception e) X2|Y  
{ 3+Qxg+<  
e.printStackTrace (); en F:>H4  
} (1R?s>3o  
} qZv =  
laKuOx}  
//日志 Pmg)v!"  
public static void log(String sMsg) .@q-B+Eg  
{ iRV~Il#~!  
System.err.println(sMsg); FR[ B v  
} uX/$CM  
;%C'FV e]  
e({9]  
public static void log(int sMsg) @f+8%I3D  
{ oR1^/e  
System.err.println(sMsg); N2'qpxOLI  
} Z?P~z07  
} }[+!$#  
lv&mp0V+  
!$;a[Te  
/* YgUH'P-  
**TestMethod.java *l+OlQI0+  
*/ B/JO~;{  
package NetFox; -t2T(ha  
"9EE1];NT  
*OJ/V O  
public class TestMethod { -|k)tvAm  
LQ11ba  
WtulTAfN  
public TestMethod() [#Lc]$  
{ ///xx/weblogic60b2_win.exe #11NPo9  
try{ Uxfl_@lJ  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 57a2^  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 'ly?P8h  
SiteFileFetch fileFetch = new SiteFileFetch(bean); :<Y}l-x  
fileFetch.start(); >_dx_<75&  
} DZ7 gcC  
catch(Exception e){e.printStackTrace ();} $ ,SF@BhO  
{GDmVWG0q  
mR\`DltoV  
} :F,O  
FWue;pw3  
).` S/F  
public static void main(String[] args) W7"{r)7  
{ *[ #;j$m  
new TestMethod(); A1)wo^,  
} -oeL{9;  
} uwf 5!Z:>  
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