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http断点续传简单实现(java)

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/* 8UANB]@Y}  
**SiteFileFetch.java @}^eyS$|!  
*/ p 7YfOUo k  
package NetFox; 5 1\N+  
import java.io.*; %N, P? ,U  
import java.net.*;  7z?r x  
I}@m6D|\  
)7j CEA03  
public class SiteFileFetch extends Thread { M-B-  
)^ky @V  
Js7D>GWP!  
SiteInfoBean siteInfoBean = null; //文件信息Bean ).Ei:/*j  
long[] nStartPos; //开始位置 .L X8ko  
long[] nEndPos; //结束位置 yM8<)6=  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 p^s k?E  
long nFileLength; //文件长度 )L%i"=<Bdy  
boolean bFirst = true; //是否第一次取文件 &>Ko}?w  
boolean bStop = false; //停止标志 J6) &b7  
File tmpFile; //文件下载的临时信息 =:!$'q:  
DataOutputStream output; //输出到文件的输出流 !/},k"p6  
PI~W6a7p  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) z z4.gkU  
public SiteFileFetch(SiteInfoBean bean) throws IOException mN9Uyz5G  
{ 7JedS  
siteInfoBean = bean; m#(tBfH[  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); WG_20JdJY  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); %Ny`d49&  
if(tmpFile.exists ()) #xopJaY  
{ ?B&@  
bFirst = false; MZ8jL,a^  
read_nPos(); S4jt*]w5b  
} l^F%fIRp)  
else ^rDT+ x  
{ rX*ATN  
nStartPos = new long[bean.getNSplitter()]; M99gDN  
nEndPos = new long[bean.getNSplitter()]; PKx ewd  
} SseMTw:  
&y}nd 7o  
gyI(O>e  
B3P#p^  
} LE|*Je3a  
a s{^~8B  
1xJc[q  
public void run() \I"UW1)B  
{ O@ GEl  
//获得文件长度 8%$Vj  
//分割文件 WB=pRC@  
//实例FileSplitterFetch C y b-}l  
//启动FileSplitterFetch线程 H8ws6}C  
//等待子线程返回 vlD!YNy  
try{ 9 pGND]tIi  
if(bFirst) 2ja@NT  
{ M =!RJ%6f  
nFileLength = getFileSize(); u7e g:0Y  
if(nFileLength == -1) e*Gm()Vu,  
{ e$E~@{[1)  
System.err.println("File Length is not known!"); (X rrnoz  
} ~9:ILCfX  
else if(nFileLength == -2) ,u^S(vxyz  
{ k+"+s bsW'  
System.err.println("File is not access!"); ',Mi D=_  
} l#FW#`f  
else vFK&63  
{ 7H-,:8  
for(int i=0;i<nStartPos.length;i++) o|s JTY  
{ <&?gpRK   
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Y}bJN%M  
} `>1"v9eF  
for(int i=0;i<nEndPos.length-1;i++) idC4yH42  
{ 2 NgEzY 5  
nEndPos = nStartPos[i+1]; LWB"}#vt  
} G36}4  
nEndPos[nEndPos.length-1] = nFileLength; U#O 6l-xe]  
} (;V=A4F-D  
} *ay>MlcV2=  
?,J N?  
Dj<]eG]  
//启动子线程 iI[Z|"a21  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; >@yHa'*9S  
for(int i=0;i<nStartPos.length;i++) 3&D;V;ON}_  
{ &=sVq^d@qe  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), R;P>_ei(LK  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), <"uT=]wZ=  
nStartPos,nEndPos,i); o@`& h} $  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); [mSK!Y@u  
fileSplitterFetch.start(); ^KU:5Bn  
} i>9/vwe  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), CjzfU*G  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); oRM,_  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", 3dnL\AqC  
nEndPos = " + nFileLength); g& y R-  
// fileSplitterFetch[nPos.length-1].start(); c3gy{:lb  
M-!eL<  
y(K?mtQ   
//等待子线程结束 zfE;)K^"  
//int count = 0; aW8Bx\q  
//是否结束while循环 ?-g=Rfpag  
boolean breakWhile = false; OQ$77]XtvL  
Jlw oSe:S  
wX6VapFboI  
while(!bStop) qAsZ,ik  
{ $X %GzrN  
write_nPos(); }2.^n{Y  
Utility.sleep(500); v hUn3|  
breakWhile = true; &(fB+VNrOH  
.,:700n+^  
Mj&f7IUO  
for(int i=0;i<nStartPos.length;i++) b9[KdVsT6^  
{ [_jTy;E  
if(!fileSplitterFetch.bDownOver) TqNEU<S/t  
{ yA%(!v5UT  
breakWhile = false; EO'[AU%~  
break; vgzNT4o  
} U9;C#9E  
} 5|ih>?C/(  
if(breakWhile) (Al.hEs'  
break; L&qzX)  
DRD%pm(  
R1z\b~@"  
//count++; }Po&6^  
//if(count>4) Yn,dM~|Cc  
// siteStop(); R/ 7G  
} "t+VF 4r  
?op6_a-wm  
uG\ +`[-{0  
System.err.println("文件下载结束!"); E+$vIYq:W  
} x.r~e)x=  
catch(Exception e){e.printStackTrace ();} t;9f7~  
} [R j=k)aBm  
<CL0@?*i9  
D"F5-s7  
//获得文件长度 jxL5L[  
public long getFileSize() byM/LE7)  
{ \oPW  
int nFileLength = -1; s> JmLtT  
try{ VdR5ZP  
URL url = new URL(siteInfoBean.getSSiteURL()); CTt3W>'=+  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 06I'#:]  
httpConnection.setRequestProperty("User-Agent","NetFox"); $|!VP'VI  
{A4"KX(U  
A%n l@`s,  
int responseCode=httpConnection.getResponseCode(); #.0^;M5Nh  
if(responseCode>=400) M'D;2qo  
{ c"%XE#D  
processErrorCode(responseCode); 2.Ym  
return -2; //-2 represent access is error hq/k}Y  
} 6hSj)  
SX|b0S,  
u0h {bu  
String sHeader; 2RKI M(~  
CD(2A,u)/  
6OMywGI[Z  
for(int i=1;;i++) $=n|MbFl  
{ /Cr0jWu _  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); j_SRCm~:  
//Utility.log(in.readLine()); h2+vl@X  
sHeader=httpConnection.getHeaderFieldKey(i); q>w@W:tZ  
if(sHeader!=null) #rzq9}9tB  
{ wH[@#UP3l  
if(sHeader.equals("Content-Length")) :{C#<g`  
{ GVZ/`^ndM  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); |_a E~_  
break; KYVB=14  
} DY?`Y%"  
} ]j0v.[SX  
else I ms?^`N  
break; ghJ81  
} o"t+G/M  
} -MoI{3a  
catch(IOException e){e.printStackTrace ();} RX:\@c&  
catch(Exception e){e.printStackTrace ();}  m2%uGqz  
N(Us9  
5xP\6Nx6&5  
Utility.log(nFileLength); *G$tfb(  
d c_^   
M cE$=Vv  
return nFileLength; k( 1rp|qf  
} ="3Hc=1?R  
BOn2`|oLuF  
UDV,co  
//保存下载信息(文件指针位置) {) 4D1  
private void write_nPos() :{%6< j  
{ O'U0Y8HN  
try{ MuYr?1<q  
output = new DataOutputStream(new FileOutputStream(tmpFile)); #"%oz^~\  
output.writeInt(nStartPos.length); `N}<lg(0#  
for(int i=0;i<nStartPos.length;i++) e{Pgz0sO Q  
{ L.lmbxn  
// output.writeLong(nPos); R3wK@D  
output.writeLong(fileSplitterFetch.nStartPos); X!,P] G  
output.writeLong(fileSplitterFetch.nEndPos); 0U ?1Yh7 m  
} mkTf}[O  
output.close(); |4pE"6A  
} Fs<kMT  
catch(IOException e){e.printStackTrace ();} -DhF> 4f  
catch(Exception e){e.printStackTrace ();} '0U+M{  
} J@(=#z8xS  
A/%K=H?  
c[?S}u|['  
//读取保存的下载信息(文件指针位置) nK1XJp  
private void read_nPos() l%.3hId-  
{ }m/aigA[1  
try{ 9*RfOdnNe  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); =(K;z9OR  
int nCount = input.readInt(); L{Epkay,{  
nStartPos = new long[nCount]; tTe\#o`  
nEndPos = new long[nCount]; &CF74AN#  
for(int i=0;i<nStartPos.length;i++) cysYjuI i  
{ F4>}mIA  
nStartPos = input.readLong(); ItHKpTe r  
nEndPos = input.readLong(); wx BQ#OE  
} ^o,Hu#  
input.close(); eI; %/6#  
}  gvYa&N  
catch(IOException e){e.printStackTrace ();} $ w:QJ~,s  
catch(Exception e){e.printStackTrace ();} #z-6mRB  
} Fe%Q8RIh_  
`,tv&siSA  
R*/%+  
private void processErrorCode(int nErrorCode) 3\|e8(bc  
{ oHB51< }  
System.err.println("Error Code : " + nErrorCode); `;*%5WD%  
} yPn5l/pDDr  
u2y?WcMv  
S%-L!V ,  
//停止文件下载 -4Zf0r1u  
public void siteStop() :,y V?E6]  
{ d%VGfSrKq  
bStop = true; W@AZ<(RI:  
for(int i=0;i<nStartPos.length;i++) 6GMQgTY^  
fileSplitterFetch.splitterStop(); CspY+%3$  
V /$qD  
8V`r*:\  
} oat*ORL  
} 'g^;_=^G  
//负责部分文件的抓取 9 Bz ~3  
**FileSplitterFetch.java BQ,]]}e43z  
*/ p82&X+v/p  
package NetFox; 8#2PJHl;  
.Gh-T{\V'  
thOQcOf0$  
import java.io.*; %A`f>v.7 c  
import java.net.*; f8L  
[{ K$sd  
F=Z|Ji#  
public class FileSplitterFetch extends Thread { ?Q="w5OOD  
8<Asg2]6  
O1Ey{2Q  
String sURL; //File URL Hwklk9U  
long nStartPos; //File Snippet Start Position [IF3 ,C  
long nEndPos; //File Snippet End Position '{QbjG%<P  
int nThreadID; //Thread's ID <tMiI)0%  
boolean bDownOver = false; //Downing is over sKB])mf]  
boolean bStop = false; //Stop identical |L.QIr,jCC  
FileAccessI fileAccessI = null; //File Access interface `Q<hL{AH  
<<6i6b  
5'?K(Jdmp  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException bT,]=h"0  
{ U P GS  
this.sURL = sURL; acdaDY  
this.nStartPos = nStart; M'$n".,p  
this.nEndPos = nEnd; lE`hC#m  
nThreadID = id; R"];`F(#  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 gsGwf[XdJ  
} o>311(:  
Eh#W*Bg  
\,!FL))yC  
public void run() 29z+<?K{  
{ epJVs0W  
while(nStartPos < nEndPos && !bStop) K;,n?Q w  
{ +IK~a9t  
7]@vPr;:  
y'*^ '  
try{ A/lxXy}D  
URL url = new URL(sURL);  [53rSr  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); 4M*UVdJ;  
httpConnection.setRequestProperty("User-Agent","NetFox"); b|u4h9  
String sProperty = "bytes="+nStartPos+"-"; I{ ;s.2  
httpConnection.setRequestProperty("RANGE",sProperty); q62TYg}  
Utility.log(sProperty); 79n,bb5  
R,x\VX!|  
GQ[: vX`  
InputStream input = httpConnection.getInputStream(); 36@)a5  
//logResponseHead(httpConnection); `S2YBKz,1  
m%m/#\J E  
qtnLQl"M  
byte[] b = new byte[1024]; |+mhYq|`  
int nRead; vo-n9Bj  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) '=G4R{  
{ )3=oS1p  
nStartPos += fileAccessI.write(b,0,nRead); xqmP/1=NO  
//if(nThreadID == 1) Xnt`7L<L  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); zq80}5%2CT  
} RvZi%)  
K%[Rv#>;q|  
vE;`y46&r  
Utility.log("Thread " + nThreadID + " is over!"); :[#HP66[O5  
bDownOver = true; r4@!QR<h  
//nPos = fileAccessI.write (b,0,nRead); f7)}A/$4+  
} "S(m1L?  
catch(Exception e){e.printStackTrace ();} &"BmCDOq  
} ?=dyU(  
} &Y\Vh}  
k`62&"T  
;gc Q9L  
//打印回应的头信息 ib/B!?/  
public void logResponseHead(HttpURLConnection con) ~QJD.'z  
{ !sfOde)$  
for(int i=1;;i++) 8E H# IiP  
{ sycN  
String header=con.getHeaderFieldKey(i); u3R0_8 _.w  
if(header!=null) "pa5+N&2-  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); +M$2:[xRT  
Utility.log(header+" : "+con.getHeaderField(header)); F[ N{7C3  
else sI, T"D?  
break; W#$ pt>h)  
} _&FcHwRy  
} C8}ujC  
=O?<WJoK  
>M<rr!|  
public void splitterStop() Q1mz~r  
{ d!{,[8&  
bStop = true; &[`p qX  
} |eAl!k  
:O-Y67>&  
\om$%FUP  
} 68V66:0  
vRp =L54z  
~P 1(%FZ  
/* K||9m+  
**FileAccess.java ^&am]W;T  
*//文件访问(定位,写) R9f*&lj  
package NetFox; - U!:.  
import java.io.*; K%P$#a  
iK#5HW{  
'IY?7+[  
public class FileAccessI implements Serializable{ _Ft4F`pM  
 Aa[p7{e  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 |Kky+*  
RandomAccessFile oSavedFile; UBs'3M  
long nPos; m]R< :_  
<%#M&9d)E  
F-k3'eyY  
public FileAccessI() throws IOException P6&@fwJ<  
{ PCF!Y(l  
this("",0); B4bC6$Lg  
} 8fKt6T  
ogbLs)&+a  
/@g D 8  
public FileAccessI(String sName,long nPos) throws IOException Z)<ljW  
{ _Isju S  
oSavedFile = new RandomAccessFile(sName,"rw"); SL zL/5s  
this.nPos = nPos; {"S"V  
oSavedFile.seek(nPos); &Ey5 H?U!  
} -'QvUHL|  
kzny4v[y  
?wt%e;  
public synchronized int write(byte[] b,int nStart,int nLen) @(Wx(3JR?}  
{ @G+Hrd6  
int n = -1; <f %JZ4p*  
try{ -"YQo  
oSavedFile.write(b,nStart,nLen); |'9%vtbM  
n = nLen; "toyfZq@  
} }dX[u`zQ  
catch(IOException e) ~McmlJzJG  
{ 7dyGC:YuTL  
e.printStackTrace (); -D?T0>  
} xQ\/6|  
kE;h[No&K  
kA1]o  
return n; |6'(yn  
} ?lW-NPr  
K:gxGRE  
Vz6p^kMB  
} GGo)k1T|)  
/) sA{q 4  
mnZ/rb  
/* ~B;kFdcVXn  
**SiteInfoBean.java 3[B*l@}j  
*/ _p<W  
package NetFox; FivgOa  
6d&dB  
-CtLL _I  
public class SiteInfoBean { ,l^; ZE  
}R4%%)j(Vj  
p \A^kX^5  
private String sSiteURL; //Site's URL o%XAw   
private String sFilePath; //Saved File's Path kW0|\  
private String sFileName; //Saved File's Name DP ,owk  
private int nSplitter; //Count of Splited Downloading File c ]M!4.  
~XQj0'  
fgIzT!fyz  
public SiteInfoBean() va F^[/ (g  
{//nSplitter的缺省值为5 = Ryh@X&  
//default value of nSplitter is 5 M]4qS('[  
this("","","",5); ,r~pf (nz  
} !`"@!  
OF J49X  
Kq#\P  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Fka&\9i  
{ /tR@J8pV  
sSiteURL= sURL; "| cNY_$&s  
sFilePath = sPath; Sm(X/P=z  
sFileName = sName; )'3(=F$+l  
this.nSplitter = nSpiltter; ATl.Qku@  
9Jd{HI=  
> 2_xRn<P  
} #=C!Xx&  
^kJ(bBY  
^0vK >  
public String getSSiteURL() z +,l"#Vv  
{ C1&~Y.6m  
return sSiteURL; p vone,y2  
} n6 D9f~8"  
1><@$kVMm~  
Lf0Y|^!S_u  
public void setSSiteURL(String value) 3Kuu9< 0  
{ &x6Z=|Ers  
sSiteURL = value; E0; }e  
} Br^4N9  
tS#=I.ET  
&XAG| #  
public String getSFilePath() hG51jVYtw  
{ L c4\i  
return sFilePath; ?# ~3%$>  
} lZ]x #v  
"2} {lu  
~,[-pZ <  
public void setSFilePath(String value) [Q+8Ku  
{ 2..b/  
sFilePath = value; u~SvR~OE  
} 4)MKYhm  
IxN0m7  
XgRrJ.  
public String getSFileName() Wm ri%  
{ >%Rb}Ki4  
return sFileName; EGpN@  
} >K:| +XbH  
/g$cQ=c  
yF2|w=!  
public void setSFileName(String value) tg =ClZ-  
{ Y'K+O  
sFileName = value; t8SvU  
} ]^aOYtKX  
/zxLnT; 5  
dJyf.VJ  
public int getNSplitter() X*f#S:kiNU  
{ ueI1O/Mi  
return nSplitter; Su" 9`  
} T%0vifoQ_$  
1,UeVw/  
v C,53g  
public void setNSplitter(int nCount) p5F=?*[}  
{ eh4`a<gC  
nSplitter = nCount; \"r84@<  
} 9vIqGz-o  
} Pnf|9?~$H  
udw>{3>  
+c4-7/kE  
/* q8&2M  
**Utility.java j"G1D-S:  
*/ 2cv!85  
package NetFox; g-G;8x'n  
\3nu &8d  
7oUecyoj  
public class Utility { kp F")0qr  
%LI[+#QE  
z}Y23W&sX  
public Utility() 3B*b d  
{ 4)- ?1?)  
Vyy;mEBg  
KmF" Ccc  
} ,q9nHZG^  
)9F o  
//线程睡眠 u7PtGN0r%  
public static void sleep(int nSecond) kH;DAphk  
{ =[A5qwyv  
try{ ai,\'%N  
Thread.sleep(nSecond); &8=wkG%  
} JSXJlau  
catch(Exception e) %@C(H%obWd  
{ V2Iq k]V%y  
e.printStackTrace (); FKYPkFB  
} +Cs[]~  
} u.\FNa  
;4(ULJ*  
//日志 *[VO03  
public static void log(String sMsg) eXs^YPi  
{ _:N+mEF  
System.err.println(sMsg); ub/Z'!  
} `.oWmBey\  
L@mNfLK  
h=?V)WSM  
public static void log(int sMsg) a7$]" T 7  
{ pFB^l|\ ]  
System.err.println(sMsg); fEv`iXZG  
} 31VDlcn E  
} " a&|{bv  
]81t~t9LQ  
4lM)ZDg  
/* .qd/ft2  
**TestMethod.java seQSDCsvw*  
*/ \,n|V3#G  
package NetFox; T[?wbYfW  
Uz4!O  
;`")3~M3*  
public class TestMethod { u& 4i=K'x8  
&*Sgyk o`  
;+ -@AYl  
public TestMethod() Fx@ovI- 5  
{ ///xx/weblogic60b2_win.exe g?7I7W~?`  
try{ kjj4%0"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); d#tqa`@~  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 7d m:L'0  
SiteFileFetch fileFetch = new SiteFileFetch(bean); QD8.C=2R  
fileFetch.start(); -RLY.@'d-M  
} %w$\v"^_Y  
catch(Exception e){e.printStackTrace ();} D,3Kx ^  
s0zN#'o]  
{th=MldJ?  
} pA%}CmrMq  
Ru&>8Ln0  
a- \M)}T  
public static void main(String[] args) 6%-RKQi  
{ L'Yg$9Vz  
new TestMethod(); |]M|I X8 o  
} )7aUDsu>4  
} *\-$.w)k  
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