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http断点续传简单实现(java)

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/* < NlL,  
**SiteFileFetch.java iVAAGZ>am  
*/ atYe$Db  
package NetFox; -0:Equ?pz  
import java.io.*; "C'T>^qw*  
import java.net.*; #@8JYzMq%  
Msl8o c  
aZB$%#'vR  
public class SiteFileFetch extends Thread { ^rssZQKY[  
CI+@G XY  
vq-# %o  
SiteInfoBean siteInfoBean = null; //文件信息Bean D'Y=}I)8Dn  
long[] nStartPos; //开始位置 #"KaRh  
long[] nEndPos; //结束位置 GPLq$^AH  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 P{%R*hb]  
long nFileLength; //文件长度 AroYDR,3+  
boolean bFirst = true; //是否第一次取文件 ,l7',@6Y  
boolean bStop = false; //停止标志 L{uQ: ;w1  
File tmpFile; //文件下载的临时信息 L6n<h  
DataOutputStream output; //输出到文件的输出流 C)R#Om  
2{I+H'w8:  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) Z<W`5sop^  
public SiteFileFetch(SiteInfoBean bean) throws IOException r0j+P%  
{ 3w$Ib}7   
siteInfoBean = bean; ;|AyP  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); )Oix$B!-  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); !7y:|k,ac  
if(tmpFile.exists ()) f\h|Z*Bv  
{ SnFAv7_  
bFirst = false; N= {0A  
read_nPos(); E%vT(Kz  
} `VD7VX,rp*  
else ]5sU =\  
{ A`ScAzx5{  
nStartPos = new long[bean.getNSplitter()]; WNWtQ2]  
nEndPos = new long[bean.getNSplitter()]; n2;Vrs,<1&  
} ;`:A(yN]T  
SeIL   
#B &%Y6E5  
YJMaIFt  
} `z~L0h  
K~Z$NS^W&  
[28Vf"#]  
public void run() {D7v[P+  
{ I.hy"y2&  
//获得文件长度 08F~6e6a8  
//分割文件 uL9O_a;!  
//实例FileSplitterFetch B'!I{LC  
//启动FileSplitterFetch线程 eg(1kDMpn  
//等待子线程返回 Ys+NIV#Q  
try{ akV-|v_  
if(bFirst) I|R;)[;X  
{ mWX{I2  
nFileLength = getFileSize(); erdA ?  
if(nFileLength == -1) ;I!Vba  
{ (;cvLop  
System.err.println("File Length is not known!"); ">x"BP  
} $J!WuOz4^i  
else if(nFileLength == -2) 5"2pU{xmK  
{  RR[1mM  
System.err.println("File is not access!"); w'zSV1  
} <(W:Q3?s  
else `IH*~d]  
{ \<Di |X1  
for(int i=0;i<nStartPos.length;i++) -E>LB\[t)  
{ jWcfQ  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); p}(pIoyUF  
} VJOB+CKE  
for(int i=0;i<nEndPos.length-1;i++) uQO\vRh0  
{ [,Fu2j]  
nEndPos = nStartPos[i+1]; *:8,w?Nt  
} iPdR;O'  
nEndPos[nEndPos.length-1] = nFileLength; wrAcVR  
} yyc4'j+  
} `{  ` W-C  
`[F[0fY-  
Wh^wKF~%  
//启动子线程 L-VisZ-FK  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; m e2$ R>@  
for(int i=0;i<nStartPos.length;i++) &Rt^G  
{ .RN2os{  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), O>[B"mM t  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), KZ$^Q<d^  
nStartPos,nEndPos,i); k@^T<Ci  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); e7M6|6nb  
fileSplitterFetch.start(); ,Y`TP4Ip  
} _`+2e-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), npMPjknl  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); a 3C\?5  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", $aDkZj  
nEndPos = " + nFileLength); z@U5  
// fileSplitterFetch[nPos.length-1].start(); {C5-M!D{<  
I\P w`  
/TY=ig1z  
//等待子线程结束 q*7:L  
//int count = 0; 1)J' pDa  
//是否结束while循环 ,$bK)|pGV  
boolean breakWhile = false; Y3bZ&G)  
U?A3>  
%,f(jQfg_  
while(!bStop) mO&zE;/[  
{ `2,F!kCt  
write_nPos(); Vw+RRi(  
Utility.sleep(500); @o>3 Bv.  
breakWhile = true; ?6//'bO:%  
?<U">8cP  
xP $\ }  
for(int i=0;i<nStartPos.length;i++) $Go)Zs-bL?  
{ QSyPtjg]  
if(!fileSplitterFetch.bDownOver) V=)' CCi{  
{ FQM9>l@6)>  
breakWhile = false; {QVs[ J1  
break; =i>i,>bv  
} wVkRrFJ  
} VF:95F;@  
if(breakWhile) zR5KC!xc  
break; l09DH+  
I 8VCR8q  
A$-\Er+f  
//count++; r>g5_"FL  
//if(count>4) .~fov8  
// siteStop(); KN".0WU  
} *{dMo,.eI  
LN`Y`G|op  
<\oD4EE_  
System.err.println("文件下载结束!"); }s:~E2?In  
} @.} @K  
catch(Exception e){e.printStackTrace ();} fT.MglJcb  
} Zw_'u=r >  
naVbcY  
6rMNp"!  
//获得文件长度 |jb,sd[=S  
public long getFileSize() 0}N"L ml  
{ @|<qTci  
int nFileLength = -1; C sCH :>  
try{ :H>0/^Mg0  
URL url = new URL(siteInfoBean.getSSiteURL()); /]-a 1  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); }70A>JBw  
httpConnection.setRequestProperty("User-Agent","NetFox"); #3_ @aq*  
~8U0(n:^  
>tE6^7B*  
int responseCode=httpConnection.getResponseCode(); LvNulMEK  
if(responseCode>=400) C/MQY:X4  
{ Fb6d1I^wR  
processErrorCode(responseCode); X<&Y5\%F  
return -2; //-2 represent access is error d fSj= 4  
} #@J{ )  
MzE1he1  
QypUBf  
String sHeader; p{AX"|QM"  
A=r8_.@2@  
wY3| 5kbDj  
for(int i=1;;i++) p#6tKY;N  
{ +mC?.B2D  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); pj Md  
//Utility.log(in.readLine()); )j. .)o  
sHeader=httpConnection.getHeaderFieldKey(i); *gOUpbtXa  
if(sHeader!=null) bWJ&SR>  
{ @a,} k<@E  
if(sHeader.equals("Content-Length")) yw >Frb5p  
{ m]Mm (7v(  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); \LM.>vJ  
break; KBa0  
} *d9RD~Ee  
} !\!j?z=O8  
else +v< \l=  
break; ij?Ww'p9>  
} a}X. ewg  
} 0wt4C% .0  
catch(IOException e){e.printStackTrace ();} OR}+) n{  
catch(Exception e){e.printStackTrace ();} yB|1?L#  
xqfIm%9i}  
gv1y%(`|n(  
Utility.log(nFileLength);  Z>pZ|  
8vQR'<,  
Zgo%Jo  
return nFileLength; k; >Vh'=X  
} D"exI]  
} L _Zmi$  
\2CEEs'  
//保存下载信息(文件指针位置) Nh\o39=  
private void write_nPos() ;vy<!@Y;8  
{ z0Z1J8Qq6.  
try{ U$ ;UW3-  
output = new DataOutputStream(new FileOutputStream(tmpFile)); H4$f+  
output.writeInt(nStartPos.length); $W%-Mm  
for(int i=0;i<nStartPos.length;i++) fk!9` p'  
{ -A zOujSS  
// output.writeLong(nPos); ^PUB~P/  
output.writeLong(fileSplitterFetch.nStartPos); !j}L-1*{ l  
output.writeLong(fileSplitterFetch.nEndPos); J|vg<[  
} f Xh{ _>  
output.close(); P3nBxw"  
} )_Z^oH ]<  
catch(IOException e){e.printStackTrace ();} [LO=k|&R  
catch(Exception e){e.printStackTrace ();} L|B! ]}  
} X4{<{D`0t8  
}F"98s W  
z#1"0Ks&P  
//读取保存的下载信息(文件指针位置) xsiJI1/68  
private void read_nPos() q@tym5  
{ 1}Y3|QxF  
try{ .h\Py[h<^  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); O<E8,MCA[a  
int nCount = input.readInt(); .(3ec/i4CF  
nStartPos = new long[nCount]; g@T}h[  
nEndPos = new long[nCount]; aNA ]hl  
for(int i=0;i<nStartPos.length;i++) 9M5W4&  
{ fI1 9p Q  
nStartPos = input.readLong(); >|yP`m   
nEndPos = input.readLong(); sG)aw`_j  
} w)B ?j  
input.close(); r?!:%L  
} C!ch !E#  
catch(IOException e){e.printStackTrace ();} o\]U;#YD  
catch(Exception e){e.printStackTrace ();} *,IK4F6>:  
} QZIzddwp  
)(_NFpM  
E AZX  
private void processErrorCode(int nErrorCode)  !Q*w]  
{ 3z u6#3^  
System.err.println("Error Code : " + nErrorCode); r7L.W  
} h(<>s#=E  
\P")Eh =d  
L`X5\D'X  
//停止文件下载 t 7o4 aBl"  
public void siteStop() AI Kz]J0;  
{ kkWv#,qwU  
bStop = true; }WaZ+Mdg\  
for(int i=0;i<nStartPos.length;i++) aKWxLe  
fileSplitterFetch.splitterStop(); n:2._s T  
bX,#z,  
\$*CXjh3G  
} r-TrA$k  
} 4d cm)Xr  
//负责部分文件的抓取 +L`}(yLJ)9  
**FileSplitterFetch.java FO%pdLs,  
*/ E #B$.K  
package NetFox; dH PvVe/  
J"LLj*,0"  
ENIg_s4  
import java.io.*; d}':7Np  
import java.net.*; ES AX}uF  
[DH4iG5  
v_Sa0}K9  
public class FileSplitterFetch extends Thread { 7C 0xKF  
Z,e|L4&  
q,O_y<uw  
String sURL; //File URL f? @Qt<+k  
long nStartPos; //File Snippet Start Position BDvkY  
long nEndPos; //File Snippet End Position 6V%}2YE?X  
int nThreadID; //Thread's ID ^4+NPk  
boolean bDownOver = false; //Downing is over D 5n\h5  
boolean bStop = false; //Stop identical j1%8r*Jj  
FileAccessI fileAccessI = null; //File Access interface 'z AvQm  
WA~[) S0  
ix2i.wdD  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException gBv!E9~l  
{ q+9->D(6  
this.sURL = sURL; wbAwmOiZ  
this.nStartPos = nStart; zGR, }v%%  
this.nEndPos = nEnd; 5L[imOM0  
nThreadID = id; m~AAO{\:b  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 Nh}-6|M  
} el*|@#k}  
os"R'GYmf  
or3OLBf*Q  
public void run() H'zAMGZa  
{ Os'E7;:1h  
while(nStartPos < nEndPos && !bStop) ?D _4KFr  
{ d{JI] !  
N=Ct3  
jmwN1Se>  
try{ jq%<Z,rh  
URL url = new URL(sURL); +;lDU}$  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); @i!+Z  
httpConnection.setRequestProperty("User-Agent","NetFox"); )/@KdEA:  
String sProperty = "bytes="+nStartPos+"-"; #%k_V+o3  
httpConnection.setRequestProperty("RANGE",sProperty); Z9$pY=8^?  
Utility.log(sProperty); dxAGO(  
z2YYxJ c&w  
IC'+{3.m8  
InputStream input = httpConnection.getInputStream(); ejZ-A?f-K  
//logResponseHead(httpConnection); e8("G[P >  
#1E4 R}B  
gi,7X\`KQ  
byte[] b = new byte[1024]; -d'F KOD  
int nRead; /B?wn=][  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) !AE;s}v)0{  
{ 8%m\J:e R  
nStartPos += fileAccessI.write(b,0,nRead); j% 7Gje[  
//if(nThreadID == 1) r+ 8Tp|%  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); X,l7>>L{g  
} ^g6v#]&WA  
i*N2@Z[  
DSRc4 |L  
Utility.log("Thread " + nThreadID + " is over!"); W`9{RZ'  
bDownOver = true; 7QTS@o-  
//nPos = fileAccessI.write (b,0,nRead); v\6.#>NQ  
} 1$03:ve1  
catch(Exception e){e.printStackTrace ();} Y QC.jnb2  
} A"M;kzAfHM  
} ~3j +hN8<  
S y <E@1  
L]z8'n,  
//打印回应的头信息 s3JzYDpy  
public void logResponseHead(HttpURLConnection con) @JhkUGG]p  
{ _VdJFjY?zc  
for(int i=1;;i++) 33lh~+C  
{ jm<^WQ%Cc  
String header=con.getHeaderFieldKey(i); (Ud"+a  
if(header!=null) [DjlkA/Zg  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); Zj]tiN f\"  
Utility.log(header+" : "+con.getHeaderField(header)); h/\ Zq  
else !O!:=wq  
break; 4K:Aqqhds  
} {= &&J@:  
} i`l;k~rP  
6)YckxN^  
=3'B$PY  
public void splitterStop() U~yPQ8jD  
{ I_8 n>\u  
bStop = true; a] c03$fK  
} B]yO  
+pq=i  
nt>3i! l  
} 8~,zv_Pl  
sqhIKw@  
!U4YA1>>  
/* aj1g9 y  
**FileAccess.java uYlyU~M:D  
*//文件访问(定位,写) Jb> X$|N'%  
package NetFox; /<T{g0s  
import java.io.*; ?Mo)&,__  
\25EI]  
VgbT/v  
public class FileAccessI implements Serializable{ GKWsJO5 n  
~FAk4z=Ed  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `j'1V1  
RandomAccessFile oSavedFile; 3dZj<(.  
long nPos; R!"`Po  
% mPv1$FH  
[C-FJ>=S  
public FileAccessI() throws IOException ^ux'-/  
{ be-HF;lZe'  
this("",0); UnVa`@P^:G  
} ;=P!fvHk  
dhP")@3K;p  
fbdpDVmpU  
public FileAccessI(String sName,long nPos) throws IOException O`_, _  
{ #t Pc<p6m  
oSavedFile = new RandomAccessFile(sName,"rw"); W"\`UzOLQ  
this.nPos = nPos; ryz NM3  
oSavedFile.seek(nPos); Ht}?=ZzW  
} /ioBc}]  
b O}&i3.L;  
/9SoVU8  
public synchronized int write(byte[] b,int nStart,int nLen) 7NOF^/nU  
{ uTO%O}D N  
int n = -1; !w/fw Oo  
try{ EcytNYn  
oSavedFile.write(b,nStart,nLen); -~J5aG[@~>  
n = nLen; @|w/`!}9q  
} B )\;Ja  
catch(IOException e) 7z\ #"~(.  
{ ]d{lS&PRlg  
e.printStackTrace (); ON>l%Ae4G  
} hH05p!2  
3H>\hZ  
iN0'/)ar  
return n; b ettOg  
} BSr#;;\  
LV$Ko_9eA  
5TeGdfu @  
} ei}(jlQp  
muK.x7zyl  
 )L":I  
/* 5D7k[+6  
**SiteInfoBean.java 77+3CME{'  
*/ m9 c`"!  
package NetFox; ;/ |tU o$  
c;a<nTLn  
ESFJN}Q%0.  
public class SiteInfoBean { Ui1s ]R  
s`v$r,N0  
#tw_`yh  
private String sSiteURL; //Site's URL m' |wlI[lq  
private String sFilePath; //Saved File's Path kPAg *  
private String sFileName; //Saved File's Name O^ &m  
private int nSplitter; //Count of Splited Downloading File G%!i="/9  
>xF&>SDC  
"HH<5  M  
public SiteInfoBean() 6u`$a&dR'l  
{//nSplitter的缺省值为5 Qk|+Gj  
//default value of nSplitter is 5 7G Erh,  
this("","","",5); a>d`g  
} CQ{{J{pU"  
 3U!=R-  
*L Y6hph"  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) tt6GtYrC 1  
{ \W=Z`w3  
sSiteURL= sURL; FKhgUnw  
sFilePath = sPath;  #3RElI  
sFileName = sName; ug"4P.wI  
this.nSplitter = nSpiltter; X1[zkb  
t0/Ol'kgs  
>r}?v3QW  
} c@nh>G:y{&  
0pH$Mk Q  
ZnuRy:  
public String getSSiteURL() tWaGCxaE  
{ 0G Q8} r  
return sSiteURL; Ul 85-p  
} 6o(.zk`d  
<*/Z>Z_c2  
qwn EVjf  
public void setSSiteURL(String value) B T {cTj0W  
{ q@ wX=  
sSiteURL = value; Imclz4'8  
} RjrQDh|((  
8|L5nQ  
O9ro{ k  
public String getSFilePath() z 9WeOs  
{ R,OT\FQ<  
return sFilePath; &wu1Zz[qcz  
} p=i6~   
:w4N*lV-  
5 5Mtjqfp  
public void setSFilePath(String value) z-sq9Qp&x  
{ G$CSZrP.  
sFilePath = value; E4.A$/s8[  
} MFWkJbZV  
* {p:C  
]xJ. OUJy  
public String getSFileName() <'hoN/g  
{ D})12qB;u9  
return sFileName; OKu~Nb*  
} EW `WFBjj  
j*GS')Cm  
W58%Zz4a  
public void setSFileName(String value) mW,b#'hy  
{ 3mg:9]X9  
sFileName = value; *Z2Ko5&Y2  
} [W3sveqj&  
GI:!,9  
N+pCC  
public int getNSplitter() ) <w`:wD  
{ N6%L4v8-}X  
return nSplitter; [l<&eI&ln  
} *Aug7 HlS  
X_,R!$wbg:  
qHd7C3  
public void setNSplitter(int nCount) #hXvGon$?  
{ W}%[i+  
nSplitter = nCount; G)o:R iq  
} {/48n83n  
} r-]%R:U*  
n(SeJk%>9  
Fp]ErDan  
/* 2{oQ  
**Utility.java (eHTXk*V`  
*/ t2m7Yh5B  
package NetFox; qc' ;<  
X7tBpyi  
Q=#FvsF#z3  
public class Utility { >>8{N)c5E  
,,ML^ey  
)gAqWbkB  
public Utility() Q DKY7"H  
{ y!q`o$nK  
GSfU*@L3  
f<'D?d)L^  
} {)Shc;Qh  
^U,Dx  
//线程睡眠  <$K7f  
public static void sleep(int nSecond) ]A1'+!1$  
{ e ]{=#  
try{ \#F>R,  
Thread.sleep(nSecond); PM&NY8|Zy  
} Zv8_<>e  
catch(Exception e) Wo,93]  
{ :H:+XIgoR  
e.printStackTrace (); GBT219Z@8  
} \vS > jB  
} 2|NQ5OA0  
/R>YDout}  
//日志 6#a82_  
public static void log(String sMsg) ]M~ 7L[  
{ VAe[x `  
System.err.println(sMsg); Id8e%)  
} <KE%|6oER  
Fw#1?/K~  
Xc~BHEp  
public static void log(int sMsg) i8f+woZL  
{ %:OX^ ^i;  
System.err.println(sMsg); SQMtR2  
} b%0@nu4  
} XQtV$Lw  
vV"I}L  
+HgyM0LFg  
/* 0vMKyT3 c  
**TestMethod.java Mh{;1$j#  
*/  D@]/%;  
package NetFox; \c!e_rZ  
RS@G.|  
aa dw#90  
public class TestMethod { cxx8I  
@3~Wukc  
TKVS%//  
public TestMethod() Q:'r p  
{ ///xx/weblogic60b2_win.exe }?HWUAL\  
try{ A.RG8"  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); 8>xd  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); CdtCxy5  
SiteFileFetch fileFetch = new SiteFileFetch(bean); `B$Pk0>5r  
fileFetch.start(); 0oqOX  
} 0WyOORuK  
catch(Exception e){e.printStackTrace ();} =-qYp0sVP  
h<n2pz}  
_94R8?\_V7  
} 8A u W>7_  
_SH~.Mt_!  
-"XHN=H  
public static void main(String[] args) m/< @Qw  
{ @4Q /J$  
new TestMethod(); z(#dL>d$'  
} $bN_0s0:'  
} l%qh^0  
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