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http断点续传简单实现(java)

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/* |_*O'#jx  
**SiteFileFetch.java =Ja]T~0A  
*/ y8L D7<1u  
package NetFox; 7/ysVWt  
import java.io.*; PMh^(j[  
import java.net.*; m-*i>4;  
];a=Pn-:}G  
l@H  
public class SiteFileFetch extends Thread { 0Lc9M-Lg  
Lz!,kwg  
Fzpfoz<N  
SiteInfoBean siteInfoBean = null; //文件信息Bean !*m5F8Qm?A  
long[] nStartPos; //开始位置 LuSLkLN  
long[] nEndPos; //结束位置 %Bn?n{ /  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 V|/NB  
long nFileLength; //文件长度 zb}9%.U  
boolean bFirst = true; //是否第一次取文件 :xD=`ib  
boolean bStop = false; //停止标志 v!Pb`LCqK  
File tmpFile; //文件下载的临时信息 /<}m? k\  
DataOutputStream output; //输出到文件的输出流 V9( @Y  
v:o({Y 1Aq  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) KgOqbSJ  
public SiteFileFetch(SiteInfoBean bean) throws IOException Mjfx~I27  
{ ~Ro9u p  
siteInfoBean = bean; s3O} 6  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); Q`D~5ci  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); YW`,v6  
if(tmpFile.exists ()) (TwnkXrR,  
{ "@d[h,TM  
bFirst = false; wsN?[=l{s  
read_nPos(); }YMy6eW4  
} t!x5fNo)  
else y[\VUzD*'  
{ m&\h4$[kql  
nStartPos = new long[bean.getNSplitter()]; l>{R`BZ/  
nEndPos = new long[bean.getNSplitter()]; +~roU{& o  
} ?~;:jz|9<'  
]dk8lZ;bo  
("+}=*?OF3  
kc @[9eV  
} zG9Y!SY\-  
!n$tr  
AvSM ^  
public void run() k RD%b[*d  
{ Zh*u(rO  
//获得文件长度 Z@&Dki  
//分割文件 Ucm :S-  
//实例FileSplitterFetch Nwt" \3  
//启动FileSplitterFetch线程 Bj}^\Pc;}  
//等待子线程返回 2eC(Ijq[a  
try{ !V\Q<So<  
if(bFirst) T G{k0cdOT  
{ t{FlB!jv  
nFileLength = getFileSize(); ;._7jFj.  
if(nFileLength == -1) 8&~~j7p,  
{ no] z1D  
System.err.println("File Length is not known!"); wUQw!%?>  
} 0iK;Egwm  
else if(nFileLength == -2) {h2TD P  
{ pT1[<X!<s  
System.err.println("File is not access!"); S_v'hlrrT  
} 9Xl5@%uz?z  
else & jczO-R^  
{ +|@rD/I6  
for(int i=0;i<nStartPos.length;i++) l)w Hl%p  
{ J.dLPKU;-  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); t|!j2<e  
} z=_Ef3`M  
for(int i=0;i<nEndPos.length-1;i++) \, &co  
{ .G(llA}  
nEndPos = nStartPos[i+1]; f0<%&2ym  
} ]oV{t<0a  
nEndPos[nEndPos.length-1] = nFileLength; QgD g}\P  
} P=+nB*hG  
} )aao[_ZS  
H_Kj7(=&>  
?wF'<kEH  
//启动子线程 |),'9  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; +sx 8t  
for(int i=0;i<nStartPos.length;i++) J}@z_^|"mJ  
{ VY"9?2?/  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), qYf |Gv  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), 7aYn0_NKp  
nStartPos,nEndPos,i); MXiQ1 x  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); C?=P  
fileSplitterFetch.start(); _s$_Sa ;  
} RZ7( J  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), mVsIAC$}8  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); drd/jH&  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", )r z+'|,  
nEndPos = " + nFileLength); *"98L+  
// fileSplitterFetch[nPos.length-1].start(); >,gvb5  
b}w C|\s  
k({\/t3i  
//等待子线程结束 c.f"Gv  
//int count = 0; { "xln/  
//是否结束while循环 :nS;W  
boolean breakWhile = false; }%`~T>/  
)T66<UDK|  
]I.n\2R]om  
while(!bStop) d90Z,nex  
{ 7GS V  
write_nPos(); G #T<`>T  
Utility.sleep(500); B_l{<  
breakWhile = true; m6yIR6H  
t"lyvI[  
p,<&zHb>K  
for(int i=0;i<nStartPos.length;i++) `)h6j)xiQ  
{ J~iBB~x.  
if(!fileSplitterFetch.bDownOver) p!V>XY'N^  
{ 9F- )r'  
breakWhile = false; 'snn~{hG  
break; 5,;`$'?a%  
} [;.`,/  
} a7/-wk  
if(breakWhile) \WrFqm#  
break; C"qU-&*v  
H:JLAK  
W85@v2b  
//count++; fiI $T:g.  
//if(count>4) w[-Fm+A>  
// siteStop(); e{9jn>\,a  
} j! NO|&k  
-/dEsgO  
1?Aga,~k:a  
System.err.println("文件下载结束!"); ph|ZG6:  
} Ei3zBS?J)  
catch(Exception e){e.printStackTrace ();} ia{c  
} vN OH&ja-s  
b*mKei  
>x@P|\  
//获得文件长度 lE ;jCN  
public long getFileSize() XC3Kh^  
{ '[(nmx'yVJ  
int nFileLength = -1; M4LktR-[  
try{ Gy Qm/I  
URL url = new URL(siteInfoBean.getSSiteURL()); }Y1>(U  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); w_4]xgS:  
httpConnection.setRequestProperty("User-Agent","NetFox"); =AEz9d ciS  
eL.7#SIr}  
NO K/<_/  
int responseCode=httpConnection.getResponseCode(); HFQR ;9]  
if(responseCode>=400) rJ'I>Q~x6  
{ o:dR5v  
processErrorCode(responseCode); i=32KI(%  
return -2; //-2 represent access is error V' 2EPYB  
} ^Ori| 4}'  
l  n }}5Q  
"%QD{z_L  
String sHeader; Y ?r po  
v)kEyX'K2d  
OAZ#|U   
for(int i=1;;i++) '69ZdP/xX  
{ tNmy& nsA  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ! sA_?2$  
//Utility.log(in.readLine()); yWHiw<  
sHeader=httpConnection.getHeaderFieldKey(i); @TA9V@?)  
if(sHeader!=null) +|%Sx  
{ kDYN>``biP  
if(sHeader.equals("Content-Length")) W;Jx<-#1  
{ `wTlyS3[  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); & Rz, J]  
break; npu6E;'l*  
} V5GkP1L  
} z&$/EP-  
else agOk*wH5  
break; i!dv0|_  
} \H5Jk$*  
} *sfD#Bi]  
catch(IOException e){e.printStackTrace ();} N<_Ko+VF  
catch(Exception e){e.printStackTrace ();} ` e{BId  
} i)$n(A)K  
gglQU"=g{  
Utility.log(nFileLength); dj[apuiF  
7/X"z=Q^|  
Zq ot{s  
return nFileLength; N\1/JW+  
} I]J*BD#n.  
/=#~  
;+I4&VieK  
//保存下载信息(文件指针位置) TQ1WVq }*  
private void write_nPos() Lg`Jp&Kg  
{ , Ut Hc]  
try{ [ij,RE7,T  
output = new DataOutputStream(new FileOutputStream(tmpFile)); r<L#q)]  
output.writeInt(nStartPos.length); 22KI]$D#f  
for(int i=0;i<nStartPos.length;i++) jV7&Y.$zF]  
{ >n7["7HHk  
// output.writeLong(nPos); z]$j7dp  
output.writeLong(fileSplitterFetch.nStartPos); vh>{_ #  
output.writeLong(fileSplitterFetch.nEndPos); {rkn q_;0  
}  8R69q:  
output.close(); af+}S9To  
} 8h?X!2Nq  
catch(IOException e){e.printStackTrace ();} 2 6:evid  
catch(Exception e){e.printStackTrace ();} 5>ST"l_ca  
} Ew^ @Aq  
dNV v4{S  
dTD5(}+J  
//读取保存的下载信息(文件指针位置) qq+MBW*  
private void read_nPos() }Pg' vJW  
{ 0v"&G<J  
try{ `:-J+<`  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); n*qN 29sx  
int nCount = input.readInt(); abY0)t  
nStartPos = new long[nCount]; cvAtwQ'  
nEndPos = new long[nCount]; }w!ps{*  
for(int i=0;i<nStartPos.length;i++) ":d*dl  
{ jgvh[@uB?  
nStartPos = input.readLong(); :?r*p>0$  
nEndPos = input.readLong(); (@ea|Fd#4  
} g^o_\ hp  
input.close(); `.k5v7!o  
} -%uy63LbHF  
catch(IOException e){e.printStackTrace ();} 5&4F,v[zp  
catch(Exception e){e.printStackTrace ();} yCM{M  
} <~%t$:  
zw:/!MS  
u2`xC4>c  
private void processErrorCode(int nErrorCode) 8g5V,3_6  
{ gB CC  
System.err.println("Error Code : " + nErrorCode); {>.>7{7  
} m(3);)d  
4IGxI7~27#  
T=? bdIl  
//停止文件下载 .{N\<01  
public void siteStop() )Ul&1UYA  
{ uaQ&&5%%J  
bStop = true; ,eELRzjl  
for(int i=0;i<nStartPos.length;i++) uU+s!C9r  
fileSplitterFetch.splitterStop(); O=O(3Pf>  
-"Gl 4)  
L/k40cEI^z  
} WX*cICb5  
} BpXEK.Xw  
//负责部分文件的抓取 HRRngk#lV  
**FileSplitterFetch.java f0F#Yi{fw  
*/ VA]ZR+m  
package NetFox; _XN~@5elrC  
F|]rA*2u  
9c5!\m1  
import java.io.*; oBUh]sR{.  
import java.net.*; &8Wlps`  
x9*ys;~w  
 g@(30{  
public class FileSplitterFetch extends Thread { CB@B.)E  
|,fh)vO  
x[m'FsR4  
String sURL; //File URL T^.{9F]*S  
long nStartPos; //File Snippet Start Position $wXih#7  
long nEndPos; //File Snippet End Position fle0c^=  
int nThreadID; //Thread's ID \2eFpy(  
boolean bDownOver = false; //Downing is over  'O1.6*K  
boolean bStop = false; //Stop identical )n7)}xy#z  
FileAccessI fileAccessI = null; //File Access interface 'o8\`\'H!  
n^Au*'  
7dhn'TW  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException k <}I<Or  
{ `]yKM0 Z  
this.sURL = sURL; qi[(*bFK7  
this.nStartPos = nStart; 'Fzuc^G(d  
this.nEndPos = nEnd; 5k`e^ARf  
nThreadID = id; s#Q _Gu  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 LsotgQ8   
} F0: &>'}  
bG1 ofsU  
d:$G|<uA  
public void run() zuj;T,R;  
{ I! ITM<Z$l  
while(nStartPos < nEndPos && !bStop) &.*T\3UO  
{ }-@I#9  
/kb$p8!C".  
\1khyF'  
try{ ]*h&hsS 0  
URL url = new URL(sURL); |x[$3R1@  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); r2)pAiTM*  
httpConnection.setRequestProperty("User-Agent","NetFox");  bn|DRy  
String sProperty = "bytes="+nStartPos+"-"; <lX:eR1  
httpConnection.setRequestProperty("RANGE",sProperty); ][ N) 2_^M  
Utility.log(sProperty); /op/g]O}  
9e76 pP(  
$@4e(Zrmo  
InputStream input = httpConnection.getInputStream(); l2M/ ,@G  
//logResponseHead(httpConnection); ;W4:#/~14  
a:xgjUt&5  
{N@Y<=+:  
byte[] b = new byte[1024]; JbVi1?c  
int nRead; 4jD\]Q="1  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %1@.7 uTN  
{ 0<"tl0p_  
nStartPos += fileAccessI.write(b,0,nRead); :=B[y D!  
//if(nThreadID == 1) nR#a)et  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); a#6,#Q"  
} A9.;>8!u  
+"G(  
/T4VJ{D  
Utility.log("Thread " + nThreadID + " is over!"); }W)Mwu'W  
bDownOver = true; _/8y1) I  
//nPos = fileAccessI.write (b,0,nRead); (T`q++  
} y#GCtkhi  
catch(Exception e){e.printStackTrace ();} )[RpZpd`*  
} D)RdOldr  
} >R) F}  
f@#w{W,3  
l+'`BBh*]  
//打印回应的头信息 AzW%+ LUD  
public void logResponseHead(HttpURLConnection con) /!o1l\i=5  
{ DD)mN) &T  
for(int i=1;;i++) IFkvv1S`  
{ ?RqTbT@~  
String header=con.getHeaderFieldKey(i); aq$62>[  
if(header!=null) Ld'EABM  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); F F(^:N  
Utility.log(header+" : "+con.getHeaderField(header)); G0^V!0I&O  
else AIf[W">\  
break; FW5*_%J  
} "&s9cO.H  
} -!JlM@  
" -<}C%C  
tzP@3+.w  
public void splitterStop() </2,2AV4q*  
{ ]VmzKA|h+  
bStop = true; +EQpD.  
} YGi/]^Nba  
23,%=U  
o7hH9iY  
} >zN" z)  
6qY\7R2+  
X~`.}  
/* z;``g"dSw  
**FileAccess.java [Ja(ArO3|[  
*//文件访问(定位,写) ,$ho2R),Fn  
package NetFox; U=_~{[/  
import java.io.*; =t ~+63)  
F?!};~$=Z  
fB@K'JQG  
public class FileAccessI implements Serializable{ nA|gQibA  
3/ yt*cr  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 -DbH6u3  
RandomAccessFile oSavedFile; GC,vQ\  
long nPos; ?T$*5d  
zLE>kK  
AD0ptHUBa  
public FileAccessI() throws IOException #%9oQ6nO  
{ *tIdp`xT/T  
this("",0); m[//_TFf]  
} UA1]o5K  
jcT{ugpq  
0m)-7@  
public FileAccessI(String sName,long nPos) throws IOException "{,\]l&o  
{ A?^A*e  
oSavedFile = new RandomAccessFile(sName,"rw"); yd{Y}.  
this.nPos = nPos; K*J4&5?/  
oSavedFile.seek(nPos); dVjcK/T<  
} MxFt;GgE8  
`ja`#%^\u  
#r78Ym'aI  
public synchronized int write(byte[] b,int nStart,int nLen) }D&"z8mP  
{ <yPq;#z(!  
int n = -1; j=!(F`/  
try{ 5e~ j  
oSavedFile.write(b,nStart,nLen); Ac*B[ywA3  
n = nLen; d;*OO xQV  
} )M&I)In'  
catch(IOException e) *B)Jv9  
{ v^FV t  
e.printStackTrace (); O?+tY y?  
} mgJ]@s}9  
;C7BoHB9  
Rh05W_?Js  
return n; 2^k^"<h5j  
} [esX{6,i  
uyS^W'fF  
{7j6$.7J$&  
} 3N)Ycf8  
:G6 xJlE|  
~_/<PIm  
/* \Nh^Ig   
**SiteInfoBean.java D]LFX/hlH  
*/ rH [+/&w5  
package NetFox; E.WNykF-  
9Y!0>&o  
c1Fru  
public class SiteInfoBean { k:(e79  
M+;!]tbc3  
Q8M:7#ySji  
private String sSiteURL; //Site's URL { c6DT  
private String sFilePath; //Saved File's Path troy^H  
private String sFileName; //Saved File's Name >qh>Qm8w  
private int nSplitter; //Count of Splited Downloading File ]ouUv7\  
)edU <1P  
xC=3|,U  
public SiteInfoBean() E@'CU9Fo  
{//nSplitter的缺省值为5 d=.n|rS4 W  
//default value of nSplitter is 5 jN5} 2 p*  
this("","","",5); ;OT#V,}r  
} 2:6Y83  
!`d832  
Hz;jJ&S  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) &zg$H,@Qp  
{ v3VLvh 2)n  
sSiteURL= sURL; \M3NasZ  
sFilePath = sPath; b> >=d)R  
sFileName = sName; A{u\8-u  
this.nSplitter = nSpiltter; ?*MV  ^IY  
C4X{Ps \  
}. Na{]<gh  
} C7c|\T  
o to wvm  
z wniS6R1  
public String getSSiteURL() k8t Na@H  
{ 0W<nE[U  
return sSiteURL; hD9' `SQ  
} 4BUK5)B  
iJynR [7  
pyb}ha  
public void setSSiteURL(String value) Pvb+   
{ 2)j#O  
sSiteURL = value; ^r?sgJ  
} ]Pg?(lr6)  
,~=z_G`R  
9< 0$mE^:  
public String getSFilePath() l#5k8+s  
{ \I o?ul}za  
return sFilePath; Sv^'CpQ  
} [> aoDJ  
K:lT-*+S  
sLpCWIy  
public void setSFilePath(String value) U K]{]-  
{ v#YS`];B  
sFilePath = value; vSHIl"h  
} "n2xn%t{  
?#{2?%_  
T\$^>@  
public String getSFileName() LF3GVu,  
{ >TJKH^7n  
return sFileName; ^VLUZ  
} |Bf:pG!  
Q1>Op$>h  
] l qFht  
public void setSFileName(String value) <=GzK:4L  
{ /{#_Um0.  
sFileName = value; #I{Yf(2Z  
} tRrY)eElS  
w _6Y+  
1{fwr1b  
public int getNSplitter() 6w`}+3  
{ (Q p] 0  
return nSplitter; ; 0_J7  
} ~ dI&> CL  
A1s=;qr  
; hRpAN  
public void setNSplitter(int nCount) owS@dbO  
{ C,e$g  
nSplitter = nCount; 576-X _a,  
} AB|VO4-?  
} p(b1I+!  
=g>7|?6>=  
D 5wR?O  
/* JV6U0$g_S  
**Utility.java r :MaAT<  
*/ @xM!:  
package NetFox; d}B_ll#j-  
:$Di.|l@7  
,I:m*.q  
public class Utility { sZP3xh[B  
hZ /  
`F`'b)  
public Utility() Vh[o[ U  
{ y2hFUq  
hm} :Me$[)  
"jN-Yd,z  
} $(mdz)Cfy  
=&g}Y  
//线程睡眠 aD3F!Sn  
public static void sleep(int nSecond) v]Q_  
{ (,9cCnvmYU  
try{ k)GuMw  
Thread.sleep(nSecond); \f Fy$  
} i I Nu`>I  
catch(Exception e) `h{mj|~  
{ bqwW9D(  
e.printStackTrace (); Mh/>qyS *2  
} "Ohpb!J9  
} x]01j4HJ  
48NXj\L[y  
//日志 6!D  
public static void log(String sMsg) o0+BQ&A)s*  
{ oX~$'/2v  
System.err.println(sMsg); %-p{?=:K  
} b0x0CMf  
^9f`3~!#bc  
6XCX#4'i%  
public static void log(int sMsg) 7D_kkhN  
{ &"6ktKrIg  
System.err.println(sMsg); bFxJ|  
} ex!w Y  
} Gy7x?  
adPU)k_j:  
Lj* =*V  
/* !!X9mI|2|  
**TestMethod.java teNQUIe-  
*/ I=Dk'M  
package NetFox; ymVd94L  
4bjp*1*]  
EKJ4_kkjM  
public class TestMethod { E/-Kd!|"  
W%ZU& YBc  
l*MUDT@M8\  
public TestMethod() W ]MJ!4  
{ ///xx/weblogic60b2_win.exe qvT+d l3#[  
try{ }Fe{s;  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); _<}5[(qu  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); &>B>+}'  
SiteFileFetch fileFetch = new SiteFileFetch(bean); )$N{(Cke2T  
fileFetch.start(); =WRU<`\  
} R6o<p<fTh  
catch(Exception e){e.printStackTrace ();} 5 9HaTq  
x9 L\"  
. pEeR  
} dnc!=Z89  
)7mJ+d[  
_q}%!#4  
public static void main(String[] args) l0 :xQV`  
{ y:zT1I@>  
new TestMethod(); L"<Eov6  
} A;HKR4p;8  
} TUYl><F5v=  
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