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http断点续传简单实现(java)

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/* <KtL,a=2+  
**SiteFileFetch.java Het>G{  
*/ Il>o60u1  
package NetFox; 0~_I9|FN  
import java.io.*; RTbV!I  
import java.net.*; rx;;|eb,  
AqQ5L>:Gq  
9bRUN<  
public class SiteFileFetch extends Thread { /*e<r6  
6{udNv X  
5+Tx01 )  
SiteInfoBean siteInfoBean = null; //文件信息Bean 8[t*VIXI  
long[] nStartPos; //开始位置 hT_Q_1,  
long[] nEndPos; //结束位置 k^ fW /  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 -Jv3D$f]a  
long nFileLength; //文件长度 "".a(ZGg  
boolean bFirst = true; //是否第一次取文件 pZ[|Q2(  
boolean bStop = false; //停止标志 8 l= EL7  
File tmpFile; //文件下载的临时信息 yn@wce  
DataOutputStream output; //输出到文件的输出流 @`nG &U  
%dr*dA'  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) lTN^c?  
public SiteFileFetch(SiteInfoBean bean) throws IOException m+7%]$  
{ !B#lZjW#  
siteInfoBean = bean; x $[_Hix  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); ;.xKVH/@  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); ME!P{ _/  
if(tmpFile.exists ()) dblf , x  
{ ^jb;4nf  
bFirst = false; ndT_;==  
read_nPos();  !a\HdQ  
} 3}3b@:<  
else ;gu4~LQw  
{ |9.J?YP8 (  
nStartPos = new long[bean.getNSplitter()]; _I3"35a  
nEndPos = new long[bean.getNSplitter()]; /pU`-  
} B<Cg_C  
^.g-}r8,  
f-H"|9  
/B 3\e3  
} l_9ZzN  
&Qj1uf92.  
Ma(Q~G .  
public void run() 91yYR*  
{ `HYj:4v'  
//获得文件长度 2?:OsA}  
//分割文件 (d,O Lng  
//实例FileSplitterFetch 8yDsl  
//启动FileSplitterFetch线程 So~QZ%YA  
//等待子线程返回 Jy "\_Vv l  
try{ #h9Gl@|  
if(bFirst) t;PG  
{ 8'qlg|{!~  
nFileLength = getFileSize(); j"pyK@v2B  
if(nFileLength == -1) 5! +{JTXa  
{ n) D  
System.err.println("File Length is not known!"); rK}sQ4z=  
} /CKnXU;  
else if(nFileLength == -2) U1fqs{>  
{ CK|AXz+EN  
System.err.println("File is not access!"); ^5?|Dj  
} car|&b  
else p/7'r  
{ ]mNsG0r6  
for(int i=0;i<nStartPos.length;i++) uTJ z"c`F  
{ eLgq )  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); XDyo=A]  
} gcO$T`  
for(int i=0;i<nEndPos.length-1;i++) & @_PY  
{ Ku uiU= (L  
nEndPos = nStartPos[i+1];  xI#rnx*  
} p15dbr1  
nEndPos[nEndPos.length-1] = nFileLength; <}c7E3Uc  
} vpdPW%B  
} :f_oN3F p  
0yMHU[):~  
%z-so?gF  
//启动子线程 -byaV;T?"  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; n;vZY  
for(int i=0;i<nStartPos.length;i++) >o& %via}  
{ ?8< =.,r  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), I 0x;rP  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), $nIE;idk  
nStartPos,nEndPos,i); hcYqiM@8>  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); d1t_o2  
fileSplitterFetch.start(); +7 j/.R  
} 7(C)vtEO:  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), KjF8T7%  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); %gSmOW2.c^  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", !Z{7X ^  
nEndPos = " + nFileLength); Vu4LC&q  
// fileSplitterFetch[nPos.length-1].start(); \`2EfYJ{  
U#PgkP[4  
Fe$o*r,  
//等待子线程结束 ZJhI|wRwD  
//int count = 0; 9PG{>W$M  
//是否结束while循环 gVJh@]8)  
boolean breakWhile = false; "WXUz  
-?{g{6  
pX!T; Re;  
while(!bStop) Ad3TD L?  
{ $3ZQ|X[|+  
write_nPos(); ]]}iSw'  
Utility.sleep(500); Iue=\qUK^  
breakWhile = true; 2,Z@<  
K$:btWSm  
t@+e#3P!  
for(int i=0;i<nStartPos.length;i++) M _cm,|FF  
{ 4@mJEi{  
if(!fileSplitterFetch.bDownOver) Ik A~+6UY  
{ W>&*.3{v  
breakWhile = false; 8NE[L#k  
break; H<g8u{ $  
} |DVFi2   
} o"P)(;  
if(breakWhile) @(N} {om  
break; s9+lC!!  
j b'M  
"qZTgCOY2  
//count++; [ws;|n h  
//if(count>4) I.~=\%Z {  
// siteStop(); ,qV7$u  
} loBW#>  
QC] <`!  
zJUT<%[U  
System.err.println("文件下载结束!"); m@L>6;*  
} :iQJ9Hdz  
catch(Exception e){e.printStackTrace ();} <1x u&Z7  
} :8N by$#V  
vtK.7AF  
V;)+v#4{  
//获得文件长度 L7xiq{t`Y  
public long getFileSize() k{|> !(Ax  
{ h:FN&E c}  
int nFileLength = -1; !Zc#E,  
try{ B7[#z{8'#  
URL url = new URL(siteInfoBean.getSSiteURL()); <RH%FhT  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); LUpkO  
httpConnection.setRequestProperty("User-Agent","NetFox"); 4[%_Bnv#AJ  
LRS,bl3}/  
.+u r+" i  
int responseCode=httpConnection.getResponseCode(); 2'Kh>c2  
if(responseCode>=400) #BH]`A J  
{ X_rv}  
processErrorCode(responseCode); eE\T,u5:  
return -2; //-2 represent access is error g@?R"  
} ]S@DVXH  
t)O]0) s  
'*&V7:  
String sHeader; wLE|J9t%Ea  
W>b\O">  
v=&xiwz}  
for(int i=1;;i++) _ KyhX|  
{ Ar_Yl|a  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); p-!/p#  
//Utility.log(in.readLine()); )lUocm  
sHeader=httpConnection.getHeaderFieldKey(i); q8R,#\T*  
if(sHeader!=null) ! 8Ro5),  
{ q 4Ok$~"I  
if(sHeader.equals("Content-Length")) }h3[QUVf%  
{ *kj+6`:CPs  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ox";%|PP1  
break; K,P`V &m?  
} ~0Zy$L/D  
} N!\1O,  
else EVLDP\w{  
break; KO[T&#y'  
} R.GDCGAL  
} =*6H!bzX  
catch(IOException e){e.printStackTrace ();} 9Nz}'a;?>  
catch(Exception e){e.printStackTrace ();} 4>B=k  
(Bpn9}F-V.  
DD>n-8M@>  
Utility.log(nFileLength); <p` F/p-  
Dv^M/z2&[  
k@>(sXs  
return nFileLength; lx ~C{tl2  
} ys7 Tq+  
y^ st T^  
XF@34b5(  
//保存下载信息(文件指针位置) DoICf1  
private void write_nPos() [8acan+ 2l  
{ 9sv#TT5V  
try{ 9El{>&Fs4  
output = new DataOutputStream(new FileOutputStream(tmpFile)); yU~w Zjw  
output.writeInt(nStartPos.length); a'>n'Y~E  
for(int i=0;i<nStartPos.length;i++) 4O{,oN~7  
{ D7jbo[GgS  
// output.writeLong(nPos); #B_H/9f(  
output.writeLong(fileSplitterFetch.nStartPos); jPc,+?  
output.writeLong(fileSplitterFetch.nEndPos); :C&6M79k  
} Cw5 B p9  
output.close(); nLrCy5R:  
} lgb q^d  
catch(IOException e){e.printStackTrace ();} srKEtd"  
catch(Exception e){e.printStackTrace ();} a:1$idj  
} 6mxzE3?G  
ClPE_Cfw~  
52'6wwv6?  
//读取保存的下载信息(文件指针位置) }Cb-7/  
private void read_nPos() @FRas00)|  
{ I(/*pa?m{  
try{ q[. p(6:  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));  -f<}lhmQ  
int nCount = input.readInt(); =C7<I   
nStartPos = new long[nCount]; "837b/>/  
nEndPos = new long[nCount]; scE#&OWF%  
for(int i=0;i<nStartPos.length;i++) ? a/\5`gnN  
{ I&% Z*H  
nStartPos = input.readLong(); ^i@0P}K<  
nEndPos = input.readLong(); eK\i={va  
} 6r h#ATep  
input.close(); x-q_sZ^8  
} +7y#c20  
catch(IOException e){e.printStackTrace ();} pqohLA  
catch(Exception e){e.printStackTrace ();} O6\c1ha  
} @$~;vS  
))7CqN  
bq}`jP~#  
private void processErrorCode(int nErrorCode) Vw&# Lo  
{ )3 '8T>^<K  
System.err.println("Error Code : " + nErrorCode); -O $!sFmY  
} E$v!Z;A  
I 6L3M\+-  
pMf ?'l  
//停止文件下载 ]#'& x%m  
public void siteStop() ahN8IV=+Gm  
{ ;[:IC^9fv  
bStop = true; .k,,PuP  
for(int i=0;i<nStartPos.length;i++) *(Z\ "o!  
fileSplitterFetch.splitterStop(); GgtYO4,  
Vf$$e)  
~bw=;xF{3  
} wF*9%K'E  
} :=:m4UJb  
//负责部分文件的抓取 AO(z l*4  
**FileSplitterFetch.java v&sl_w/tn  
*/ T#&X7!4  
package NetFox; 7GJcg7s*T  
NBw{  
4Q,|7@  
import java.io.*; @J'tPW<$  
import java.net.*; j@/p: fk  
xg'xuz$U  
79+i4(H  
public class FileSplitterFetch extends Thread { l4& l)4Rx  
.OlPVMFt  
R I:kp.V  
String sURL; //File URL }LoMS<O-[  
long nStartPos; //File Snippet Start Position NE| Q0g  
long nEndPos; //File Snippet End Position }V 4u`=  
int nThreadID; //Thread's ID 8\+DSA  
boolean bDownOver = false; //Downing is over `~N jBtQ  
boolean bStop = false; //Stop identical ehZ/J5  
FileAccessI fileAccessI = null; //File Access interface vPrlRG6  
D8WKy  
@z`eqG,']  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException @=BApuer+  
{ cG1iO:  
this.sURL = sURL; x+[ATZ([  
this.nStartPos = nStart; #[Rs&$vQm  
this.nEndPos = nEnd; rrG}; A  
nThreadID = id; RW<4",  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 &<- S-e  
} R_ )PbFw  
m!3D5z]n9  
uF[~YJ>  
public void run()  +&<k}Mz  
{ 7zowvE?#  
while(nStartPos < nEndPos && !bStop) 60WlC0Y~u  
{ fk\]wFj  
ONF x -U]  
mRxeob  
try{ tY#Zl 54~{  
URL url = new URL(sURL); `w)yR>lqh  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); XI,=W  
httpConnection.setRequestProperty("User-Agent","NetFox"); CQ7NQ^3k  
String sProperty = "bytes="+nStartPos+"-"; ?[)V  
httpConnection.setRequestProperty("RANGE",sProperty); 7/)0{B4U'  
Utility.log(sProperty); =JxEM7r  
Z=]ujlD  
; FHnu|  
InputStream input = httpConnection.getInputStream(); 7t/Y5Qf  
//logResponseHead(httpConnection); h\+8eeIl  
`$vf9'\+  
\$gA2r  
byte[] b = new byte[1024]; =>@ X+4Kb  
int nRead; 8T Tj<T!N  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) \~  l"  
{ PO ,zP9  
nStartPos += fileAccessI.write(b,0,nRead); 35:RsL  
//if(nThreadID == 1) zT93Sb  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); .eyJ<b9  
} f*VXg[&\\F  
JkKbw&65  
8fK/0u^`d  
Utility.log("Thread " + nThreadID + " is over!"); gu&W:FY  
bDownOver = true; |\94a  
//nPos = fileAccessI.write (b,0,nRead); n3$u9!|P  
} 3#eAXIW[  
catch(Exception e){e.printStackTrace ();} 3EE_"}H>  
} t[MM=6|Wb  
} "6v_<t`q"  
n$E$@  
w}e_ 17A  
//打印回应的头信息 E%a&6W  
public void logResponseHead(HttpURLConnection con) l8e)|MSh  
{ $f>(TW  
for(int i=1;;i++) ^)h&s*  
{ +{#Z^y6&  
String header=con.getHeaderFieldKey(i); ;j+*}|!  
if(header!=null) xc7Rrh]}  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); dV-6l6  
Utility.log(header+" : "+con.getHeaderField(header)); T&}KUX~Q/  
else b~(S;1NS'  
break; ({D>(xN   
} 6P)DM  
} ,k(B>O~o  
fUZCP*7>  
(0rcLNk{|  
public void splitterStop() 8G3.bi'q   
{ )}Cf6 m}  
bStop = true; yw1Xxwc  
} '$5d6?BC`3  
}g:'K  
XXeDOrb  
} U /xzl4m6  
L@f&71  
] v:"    
/* fA=Lb^,M  
**FileAccess.java ezri9\Ju  
*//文件访问(定位,写) Q5_,`r`  
package NetFox; 15%6;K?b  
import java.io.*; w{N8Y ~O  
Pon0(:#1  
L=P8;Gj)  
public class FileAccessI implements Serializable{ dCLNZq h6  
/+WC6&  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 %ofq  
RandomAccessFile oSavedFile; ,wy;7T>ODd  
long nPos; Y@qugQM>  
^N`KT   
yN06` =  
public FileAccessI() throws IOException L x iN9  
{ e)3Mg^  
this("",0); GoPMWbI7  
} @gQ?cU7  
\x5>H:\Y  
ZT`" {#L  
public FileAccessI(String sName,long nPos) throws IOException MJa` 4[/  
{ "#iO{uMWb  
oSavedFile = new RandomAccessFile(sName,"rw"); TJB4N$-}A  
this.nPos = nPos; e-.(O8  
oSavedFile.seek(nPos); 1f?Fuw  
} uzLm TmM+  
`m$,8f%j6_  
$U(D*0+o/  
public synchronized int write(byte[] b,int nStart,int nLen) mxe\+j#  
{ <TS ps!(#  
int n = -1; !>&G+R+k  
try{ J%fJF//U  
oSavedFile.write(b,nStart,nLen); a FWTm,)  
n = nLen; g;:3I\ L  
} G/w@2lYx  
catch(IOException e) OT"jV  
{ B%o%%A8*g  
e.printStackTrace (); =PnNett}a  
} dkSd Y+Q  
)]Sf|@K]  
PTTUI  
return n; ]{I>HA5[  
} y{XNB}E  
*$/Go8t4u  
$jBi~QqOf  
} {xP-p"?p  
*Tmqs@L  
gLx?0eBBA  
/* T>&dPVmG,  
**SiteInfoBean.java u!fZ>kS  
*/ 6.a>7-K}%  
package NetFox; ^{NN-  
VRHS 4  
x_l8&RIB*  
public class SiteInfoBean { nppSrj?  
R/6 v#9m7  
A}3E)Qo=G  
private String sSiteURL; //Site's URL r\y\]AmF  
private String sFilePath; //Saved File's Path ZY;g)`E1  
private String sFileName; //Saved File's Name ")NQwT}  
private int nSplitter; //Count of Splited Downloading File KCqz]  
7JY9#+?p>  
:JXcs39  
public SiteInfoBean() -vt6n1A&b  
{//nSplitter的缺省值为5 UA#=K+2  
//default value of nSplitter is 5 xx?0Ftuq  
this("","","",5); <YWu/\{KT  
} ol_&epG;ST  
3;!a'[W&p  
/N@NT/.M<  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) mmMiA@0  
{ Yt r*"-  
sSiteURL= sURL; MJK PpQ(,  
sFilePath = sPath; .&K?@T4l  
sFileName = sName; XD[9wd5w8  
this.nSplitter = nSpiltter; lHu/pSu@k  
9(bbV5}  
GW9,%}l^;  
} 'n?"f|G  
w}29#F\]R  
HS1{4/  
public String getSSiteURL() kC'm |Y@T  
{ %,d+jBM  
return sSiteURL; U:$`M,762Z  
} ubsx NCqD  
= @FT$GQ  
u4[JDB7tH  
public void setSSiteURL(String value) XW{cC`&  
{ #O'g*]j  
sSiteURL = value; YKx+z[A/p  
} \;"S>dg  
F<)f&<5E-  
@Z96902<t  
public String getSFilePath() 6$fwpW  
{ gX* &RsF  
return sFilePath; cr^R9dv  
} "7?xaGh8  
1+tPd7U  
^SwU]e  
public void setSFilePath(String value) @*$"6!3s5  
{ 7 S%`]M4;  
sFilePath = value; % <h2^H\O  
} V. o*`V  
J!'IkC$>  
w *o _s  
public String getSFileName() **ls 4CE<  
{ zXd#kw;  
return sFileName; YIYuqtnSJ  
} e"2x!(&n(  
u5,vchZ  
d-]!aFj|U  
public void setSFileName(String value) b_@bS<wsF}  
{ F<,"{L  
sFileName = value; t 9_&n.z  
} `oE.$~'  
fl*49-d  
Ba n^wX  
public int getNSplitter() =1mIk0H`  
{ 3LVL5y7|  
return nSplitter; &2W`dEv]?  
} f{'N O`G  
JJP!9<  
y<y9'tx  
public void setNSplitter(int nCount) QW%xwV?8  
{ QX9['B<  
nSplitter = nCount; 6 %T_;"hb  
} -"xC\R  
} -}Rh+n`  
_%aT3C}k  
H]Gj$P=k  
/* hud'@O"R+  
**Utility.java ,9 .NMFn  
*/ 0fR?zT?  
package NetFox; G<t _=j/r  
z'EphL7r   
V>Nw2u!!  
public class Utility { 1sfs!b&E  
' PmBNT  
~hU^5R-%  
public Utility() 'W[Nr  
{ CWnRRZ}r  
JZD&u6tB   
 /?6  
} ;7!u(XzN  
T{ /\q 5  
//线程睡眠 zc>LwX}<  
public static void sleep(int nSecond) m] @o1J  
{ J5\2`U_FZ  
try{ FsfP^a  
Thread.sleep(nSecond); W1UqvaR  
} N3Z6o.k  
catch(Exception e) (m=F  
{ W-vEh  
e.printStackTrace (); ~G~:R  
} L4Si0 K  
} cA+O]",}  
}4xz,oN  
//日志 $ 2k9gO  
public static void log(String sMsg) rE.z.r"O  
{ 2iWxx:e  
System.err.println(sMsg); g0RfvR  
} Il<ezD{  
\J{ %xW>  
=]sM,E,n  
public static void log(int sMsg) 4)d#dy::\  
{ .A <n2-  
System.err.println(sMsg); ':T6m=yv  
} 0 oHnam  
} 7p,!<X}%  
m?<5-"hz  
&$_#{?dPt  
/* P.]O8r  
**TestMethod.java IZ+ZIR@}ci  
*/ {>>Gc2UT  
package NetFox; x% Eu.jj  
p87VJ}  
<(2,@_~@r  
public class TestMethod { 'FGf#l<  
8x<; AL|`  
|'12Kv]#Xa  
public TestMethod() </7?puVR  
{ ///xx/weblogic60b2_win.exe 0'^zIL#.  
try{ V?Ye^ -29  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); K#'{Ko  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); 8'Bik  
SiteFileFetch fileFetch = new SiteFileFetch(bean); {;Y2O.lV  
fileFetch.start(); tje   
} A(qy>x-BI  
catch(Exception e){e.printStackTrace ();} e/V8lo  
GAcU8  MD  
{@`Z`h" N  
} ik|iAWy  
KN zm)O  
4krK CD>|G  
public static void main(String[] args) o_ SR  
{ qi-!iT(fe  
new TestMethod(); h8tKYm  
} wr;8o*~  
} F /% 5 r{  
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