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http断点续传简单实现(java)

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/* Q>/C*@  
**SiteFileFetch.java I *x[:)X8  
*/ '&.#  
package NetFox; :> D[n1v  
import java.io.*; #[zI5)Meh  
import java.net.*; ZZcEt  
R&|mdY8  
t<~$  
public class SiteFileFetch extends Thread { D|rFu  
g0>,%b  
SV:4GVf  
SiteInfoBean siteInfoBean = null; //文件信息Bean HHq_P/'  
long[] nStartPos; //开始位置 G2t;DN(  
long[] nEndPos; //结束位置 2R=DB`3  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 8'<-:KG  
long nFileLength; //文件长度 )t$,e2FY  
boolean bFirst = true; //是否第一次取文件 @fs`=lL/  
boolean bStop = false; //停止标志 v z^<YZMu  
File tmpFile; //文件下载的临时信息 q-]`CW]n  
DataOutputStream output; //输出到文件的输出流 *H?!;u=8  
,Y|^^?'j Q  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) bx]N>k J  
public SiteFileFetch(SiteInfoBean bean) throws IOException p3]_}Y D[#  
{ :T]o)  
siteInfoBean = bean; xEf'Bmebk  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ]xX$<@HR  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 0KMctPT]p  
if(tmpFile.exists ()) 9Xl`pEhC  
{ 356>QW'm  
bFirst = false; Cl ^\OZN\=  
read_nPos(); OH5>vV 'i  
} Lb;zBmwB  
else N@O8\oQG  
{ )dY=0"4Z  
nStartPos = new long[bean.getNSplitter()]; w" SoeU  
nEndPos = new long[bean.getNSplitter()]; D[_|*9BC  
} UilMv~0  
R,9[hNHWGs  
Row)hx8  
S+'rG+NJ  
} SfJ./ny  
}?z@rt^  
0Z0:,!  
public void run() 8zA=;~GHP  
{ ({JHZ6uZ  
//获得文件长度 4m*M,#mV  
//分割文件 6oLwfTy  
//实例FileSplitterFetch (9<guv  
//启动FileSplitterFetch线程 Q$:![}[(  
//等待子线程返回 ow0!%|fO  
try{ ;9~6_@,@o  
if(bFirst) yU8{i&w4  
{ IkrF/$r  
nFileLength = getFileSize(); hGbj0   
if(nFileLength == -1) VQ0fS!5'  
{ +hE(Ra#  
System.err.println("File Length is not known!"); hSFn8mpXT  
} ax{ ;:fW  
else if(nFileLength == -2) Y$Q|J4z  
{ y`$Q \}fS  
System.err.println("File is not access!"); FBpH21|/y  
} l5g$vh\aQ]  
else 1j:Wh  
{ *^RmjW1I  
for(int i=0;i<nStartPos.length;i++) J|X 6j&-  
{ $ &P >r  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); [5uRS}!  
} A |3tI  
for(int i=0;i<nEndPos.length-1;i++) 7zHh@ B:]  
{ jCrpL~tWT  
nEndPos = nStartPos[i+1]; H|ER  
} srYJp^sC  
nEndPos[nEndPos.length-1] = nFileLength; 7UL qo>j  
} nPs7c %  
} oyNSh8c7c  
zGc: @z  
n+BJxu?  
//启动子线程 3/b;7\M  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +,yK;^b  
for(int i=0;i<nStartPos.length;i++) zoDH` h_  
{ yuDZ~0]R  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), TYlbU<  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), {X*^s5{;H  
nStartPos,nEndPos,i);  ;b`[&g  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); K =wBpLB  
fileSplitterFetch.start(); XuD=E  
} rHf&:~   
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), +J{0 E  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); <JV"@H=  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", Kh4$ wwn  
nEndPos = " + nFileLength); +<}0|Xl&  
// fileSplitterFetch[nPos.length-1].start(); NM0tp )h  
ZxlAk+<]  
aB]m*~  
//等待子线程结束 <)\y#N  
//int count = 0; 7lS#f1E  
//是否结束while循环 p/2jh&  
boolean breakWhile = false; {@<J_ A  
&f7fK|}  
V\})3i8  
while(!bStop) 0]D{Va  
{ bJYda)  
write_nPos(); 6m VuyI  
Utility.sleep(500); t ^[8RhD  
breakWhile = true; xB@|LtdO9;  
xS7$%w['  
h.!}3\Y  
for(int i=0;i<nStartPos.length;i++) =56T{N  
{ pSm $FBW h  
if(!fileSplitterFetch.bDownOver) % , N<  
{ 0<8XI>.3D  
breakWhile = false; UjOB98Du  
break; }?&k a$rI  
}  Y!WG)u5  
} ,R$u?c0>'&  
if(breakWhile) <H0R&l\  
break; `'\t$nU  
4;HJ;0-ps  
dB+N\HBY  
//count++; n!')wIk  
//if(count>4) 5C"QE8R o  
// siteStop(); <5G{"U+ \  
} .`7cBsXH  
N`E-+9L)  
8/t$d#xHI  
System.err.println("文件下载结束!"); h'$QC )P  
} rJa$9B*^  
catch(Exception e){e.printStackTrace ();} "+zCS|   
} sP-^~ pp  
@]q BF]6  
XxDaz1  
//获得文件长度 _:+ KMR  
public long getFileSize() O:{U^K:*  
{ DAwqo.m  
int nFileLength = -1; gPu2G/Y  
try{ sHcTd>xS  
URL url = new URL(siteInfoBean.getSSiteURL()); ]`bQW?  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); MWNPPYww  
httpConnection.setRequestProperty("User-Agent","NetFox"); 11|Rdd+}  
 PlYm&  
L{E^?iX  
int responseCode=httpConnection.getResponseCode(); %L [&,a  
if(responseCode>=400) pA;-v MpMj  
{  e(NLX`  
processErrorCode(responseCode); `]LSbS  
return -2; //-2 represent access is error /XudV2P-CA  
} 4CQ"8k(S"  
w nTV|^Q  
lNv".Y=l  
String sHeader; $7QoMV8V  
zE)~0v4  
Fb/XC:AD  
for(int i=1;;i++) QI]Ih  
{ Sa"9^_.2#  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 'TTUN=y  
//Utility.log(in.readLine()); PyA&ZkX>  
sHeader=httpConnection.getHeaderFieldKey(i); ^1Xt]T`e  
if(sHeader!=null) }n7t h  
{ bu&t'?z x!  
if(sHeader.equals("Content-Length")) aF|d^  
{ `z0{S!  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); XE3'`D !  
break; ,Rx{yf]k  
} ?0_7?yTR/  
} .bVmqR`  
else _SACqamo5s  
break; JlKM+UE :  
} +,v-=~5  
} ubu?S%`  
catch(IOException e){e.printStackTrace ();} &TG5rUUg  
catch(Exception e){e.printStackTrace ();} 7O`o ovW$  
W23]Bx  
SEl#FWR  
Utility.log(nFileLength); u*7Z~R  
!GW ,\y  
aZKOY  
return nFileLength; r-kMLw/)  
} PY3ps2^K.  
>/<:Q  &  
0F#>CmD  
//保存下载信息(文件指针位置) 4f~["[*ea  
private void write_nPos() F?m?UQS'u  
{ zq1mmFIO  
try{ hh~n#7w~IR  
output = new DataOutputStream(new FileOutputStream(tmpFile)); 51# "3S  
output.writeInt(nStartPos.length); &x-TW,#Ks  
for(int i=0;i<nStartPos.length;i++) qn"D#K'&(  
{ `o79g"kxe  
// output.writeLong(nPos); !:LJzROh  
output.writeLong(fileSplitterFetch.nStartPos); o{*ay$vA]  
output.writeLong(fileSplitterFetch.nEndPos); CK_(b"  
} * n(> ^  
output.close(); _{jP;W  
} sA9 &/p/  
catch(IOException e){e.printStackTrace ();} ^MD;"A<  
catch(Exception e){e.printStackTrace ();} 8hA^`Y  
} Fg/dS6=n`?  
XYx 6V  
gPzL*6OS A  
//读取保存的下载信息(文件指针位置) h{ lDxOH*  
private void read_nPos() 44\>gI<  
{ 7@a 0$coP  
try{ 8u2+tB  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  n i  
int nCount = input.readInt(); }.)s%4p8  
nStartPos = new long[nCount]; cgC\mM4Nla  
nEndPos = new long[nCount]; z"DkFvA  
for(int i=0;i<nStartPos.length;i++) A>NsKWf{  
{ X E}H3/2  
nStartPos = input.readLong(); }<MR`h1  
nEndPos = input.readLong(); +:6Ii9G N  
} Lt#'W  
input.close(); 5j"1z1_&  
} S bsouGD,{  
catch(IOException e){e.printStackTrace ();} Ni*Wz*o  
catch(Exception e){e.printStackTrace ();} . BO<  
} RA a[t :|  
Bn]K+h\E  
7:h!Wj -a]  
private void processErrorCode(int nErrorCode) <-UOISyf  
{ J NC  
System.err.println("Error Code : " + nErrorCode); n,P5o_^:  
} Swtbl`,  
:9l51oE7  
\g-j9|0  
//停止文件下载 p4VqV6LwD  
public void siteStop() LF*Q!  
{ |0bc$ZY:  
bStop = true; 2aw&F Z?  
for(int i=0;i<nStartPos.length;i++) Bb Jkdt7  
fileSplitterFetch.splitterStop(); }tST)=M`  
^T4Ay=~{  
;52'}%5  
} Jf:,y~mV  
} km:nE: |  
//负责部分文件的抓取 H L<s@kEZ  
**FileSplitterFetch.java tn/T6C^)  
*/ Z\>, ),O  
package NetFox; cJn HW  
0)uYizJce  
}xn_6  
import java.io.*; }bB` (B,m  
import java.net.*; h3u1K>R)  
=Pe><k  
,:v&4x&=  
public class FileSplitterFetch extends Thread { @?B6aD|jE  
=G-N` 39  
6k])KlJ2;  
String sURL; //File URL 4ax|Vb)D  
long nStartPos; //File Snippet Start Position  W^g[L:s  
long nEndPos; //File Snippet End Position w,.qCpT$_  
int nThreadID; //Thread's ID ySdN;d:q  
boolean bDownOver = false; //Downing is over N:+ taz-  
boolean bStop = false; //Stop identical fW0$s`  
FileAccessI fileAccessI = null; //File Access interface wpPn}[a  
83 ]PA<R  
'bW5Fr>W  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException ]]iO- }  
{ qFR dg V>8  
this.sURL = sURL; 96|[}:+$&:  
this.nStartPos = nStart; y@vj;3:  
this.nEndPos = nEnd; 2%rLoL$Y2+  
nThreadID = id; &hZwZgV +3  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 B(HT.%r^A  
} p5 ]_}I`+2  
BQgoVnQo_c  
{_ V0  
public void run() "/x_>ui1F  
{ LZ~`29qw(  
while(nStartPos < nEndPos && !bStop) ~o15#Pfn/  
{ T|'&K:[TJ  
b#Kq[}  
(wt+`_6  
try{ =_=*OEgO]  
URL url = new URL(sURL); *:_~Nn9_R;  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); /Ic[N&  
httpConnection.setRequestProperty("User-Agent","NetFox"); OHp5z? z  
String sProperty = "bytes="+nStartPos+"-"; p6 xPheD  
httpConnection.setRequestProperty("RANGE",sProperty); v"1Po_`  
Utility.log(sProperty); BD;H   
zQuM !.  
H30OUrD  
InputStream input = httpConnection.getInputStream(); @Jv# fr  
//logResponseHead(httpConnection); #V 43=  
gT1P*N;v  
|'hLa  
byte[] b = new byte[1024]; jMpa?Jp1  
int nRead; SN]LeXesS  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) ,jh~;, w2  
{ -l*A  
nStartPos += fileAccessI.write(b,0,nRead); \aSz2lxEHn  
//if(nThreadID == 1) ZCiY,;c  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); o42`z>~  
} Pern*x9$  
{7#03k  
WfVMdwz=  
Utility.log("Thread " + nThreadID + " is over!"); K; kM_%9u  
bDownOver = true; C|e+0aW  
//nPos = fileAccessI.write (b,0,nRead); `1'5j "v  
} 9&jPp4qG  
catch(Exception e){e.printStackTrace ();} LdWc X`K  
} >BiRk%x  
} IcoowZZ   
70iH0j)  
>!BFt$sd  
//打印回应的头信息 TgaYt\"i[  
public void logResponseHead(HttpURLConnection con) <f%/px%1  
{ 9Q[>.):  
for(int i=1;;i++) -0|K,k  
{ W);W.:F  
String header=con.getHeaderFieldKey(i); xh'^c^1  
if(header!=null) #( uj$[o  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); <'*4j\*  
Utility.log(header+" : "+con.getHeaderField(header)); qZ\ L  
else @ ^. *$E5  
break; Ml`vx  
} %8D?$v"#Z  
} 1X@b?6  
A@ VaaX  
@l>Xnqx)  
public void splitterStop() 6"%qv`.Fp  
{ w~-X>~}  
bStop = true; ( pD7  
} vgk9b!Xd  
Vipp /WV  
~%P3Pp  
} e[4V%h  
Yo'K pdn  
(T;9us0  
/* T&/_e   
**FileAccess.java nLd~2qBuv  
*//文件访问(定位,写) &z ksRX  
package NetFox; 5P\N"Yjx'  
import java.io.*; _;G=G5r  
iwo$\  
/co%:}ln  
public class FileAccessI implements Serializable{ 3H'*?|Y(#  
FfXZ|o$;  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 `vEqj v  
RandomAccessFile oSavedFile; b`]M|C [5  
long nPos; *<dHqK`?C  
u+DX$#-n!]  
j |td,82.  
public FileAccessI() throws IOException 5B|,S1b  
{ \3j)>u,r  
this("",0); AfE%a-;:  
} ZY Kd  
G+C} <S}  
n_;S2KM  
public FileAccessI(String sName,long nPos) throws IOException 'z](xG<  
{ DPeVKyjU  
oSavedFile = new RandomAccessFile(sName,"rw"); {rfte'4;=  
this.nPos = nPos; Y-~;E3(  
oSavedFile.seek(nPos); ?Ccw4]YO,=  
} bX&e_Pd  
T/Q==Q{W:  
2fP~;\AP  
public synchronized int write(byte[] b,int nStart,int nLen) 9fCO7AE0#  
{ <?4cWp|i  
int n = -1; -pX|U~a[  
try{ jJ-d/"(  
oSavedFile.write(b,nStart,nLen); V0T<eH<  
n = nLen; U#"WrWj  
} g-eq&#  
catch(IOException e) T0?uC/7H  
{ nrbazyKm  
e.printStackTrace (); fp-m.d:|  
} I4ctxMVP  
3.~h6r5-  
9 P~d:'Ib  
return n; xH@'H?  
} tx)OJY  
 Q>[Ce3  
X\'E4  
} z.j4tc9F/5  
j88=f#<  
?q6Z's[  
/* 8E 9{ Gf  
**SiteInfoBean.java ?"u'#f_  
*/ )O -cw7 >  
package NetFox; 26}u4W$  
FdM<;}6T  
g~|y$T  
public class SiteInfoBean { R9q0,yQW  
;x16shH  
!c."   
private String sSiteURL; //Site's URL <L2GUX36#  
private String sFilePath; //Saved File's Path -O /T?H  
private String sFileName; //Saved File's Name *bU% @O  
private int nSplitter; //Count of Splited Downloading File uYabJqV  
]'6'<S  
<B=[hk!  
public SiteInfoBean() {9Xm<}%u]]  
{//nSplitter的缺省值为5 gu!](yEgl  
//default value of nSplitter is 5 [JZ  h*A  
this("","","",5); Eh {up  
} *F|i&2  
/Go>5 B>  
{sl~2#,}b1  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) avV mY|I  
{ wn{]#n=|l  
sSiteURL= sURL; InP[yFV-z  
sFilePath = sPath; ~@?"' !U  
sFileName = sName; ,,Jjr[A_j  
this.nSplitter = nSpiltter; /[6:LnaE  
[~!.a\[RW  
,5=kDw2  
} e7lo!( >#  
Yu1QcFuy  
cNx \&vpd  
public String getSSiteURL() i<J^:7  
{ i'Wcf1I-=  
return sSiteURL; 89db5Dx  
} LH,]vuXh  
E`(5UF*>  
VZt;P%1;h  
public void setSSiteURL(String value) \u{Jf'g  
{ R !Fx)xj  
sSiteURL = value; Kyu@>9Ok  
} An/>0 5|  
k"5`:qL  
\ hrBq^I  
public String getSFilePath() 4bPqmEE  
{ G 2!}R  
return sFilePath; ypgliq(  
} IN<:P  
>G<4R o"  
+jv }\Jt  
public void setSFilePath(String value) G2=F8kL  
{ D 8gQR Q  
sFilePath = value; ?U}sQ;c$  
} vwm|I7/w  
y9=t;qH@|  
)nJzSN=>$  
public String getSFileName() 1bT' u5&  
{ ]"C| qR*  
return sFileName; YGfA qI y  
} gHp'3SnS  
>c}:   
q|R+x7x  
public void setSFileName(String value)  ^8b~ZX  
{ ! Zno[R  
sFileName = value; QjehDwt|  
} c5Z;%v |y  
?OdV1xB  
UB5}i('L  
public int getNSplitter() 1d=0q?nH  
{ K3a>^g  
return nSplitter; L-`(!j  
} Q -M rH   
7ytm .lU  
9)ACgz&(  
public void setNSplitter(int nCount) aIQrb  
{ !&'# a  
nSplitter = nCount; k,a,h^{}j  
} Lr K9F^c  
}  =|^X$H  
q2[+-B)m  
BT&rp%NO6l  
/* }*xC:A%aS  
**Utility.java C<zx'lw!  
*/ Z'voCWCd  
package NetFox; 5Xp$ yX =  
9`OG  
,G916J*XA  
public class Utility { jK& Nkp  
iSnIBs9\  
Kh>?!` lL  
public Utility() 2q2p=H>&  
{ ju8',ZC  
& gY;`*<  
THrc H  
} (k7;  
EG'7}W  
//线程睡眠 i)A`Vpn  
public static void sleep(int nSecond) _Cu[s?,kS  
{ OI)&vQ5k  
try{ *=($r%)  
Thread.sleep(nSecond); ~5-~q0Ge  
} pP?<[ql[w  
catch(Exception e) ]s1TJw [B  
{ Se!gs>  
e.printStackTrace (); (1QdZD|  
} _Ym&UY.u#  
} *O"%tp6  
!X \Sp}  
//日志 c@0l-R{q  
public static void log(String sMsg) ek Y?  
{ nEjo,   
System.err.println(sMsg); aL_;`@4  
} ?AqrlR]5  
BZ]&uD|f  
7AZ5%o  
public static void log(int sMsg) 6Y0/i,d*  
{ ?7rmwy\  
System.err.println(sMsg); {jj]K.&  
} ;`X`c  
} J>,'P^  
fY| @{]rx  
v*vub#wP  
/* D'HL /[@`  
**TestMethod.java  ` 4s#5g  
*/ >=Rd3dgDG  
package NetFox; &-EyM*:u!  
B`'}&6jr.  
?M*C*/R  
public class TestMethod { 6/p]jN  
Yke<Wy1  
{[(W4NAlH  
public TestMethod() r9p?@P\:[  
{ ///xx/weblogic60b2_win.exe g7E`;&f  
try{ ONg<  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); mvW^P`nB  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); MY0[Oq cm=  
SiteFileFetch fileFetch = new SiteFileFetch(bean); +oxqS&$L  
fileFetch.start(); FvtM~[Q  
} jk WBw.(  
catch(Exception e){e.printStackTrace ();} K-g=td/@  
&;uGIk>s  
baO&n  
} VNOK>+  
LN,$P  
Zp% ""  
public static void main(String[] args) @E&X &F%  
{ f4@#pnJ3po  
new TestMethod(); RP ScP  
} #/& q  
} AOvH&9**  
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