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http断点续传简单实现(java)

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/* ~v\hIm3=m  
**SiteFileFetch.java [?I/Uo8  
*/ Vrg3{@$  
package NetFox; JT#7yetk'  
import java.io.*; B0"0_n7-  
import java.net.*; O%VA)<  
'z-D%sCA  
h"8QeX:((  
public class SiteFileFetch extends Thread { VWD.J  
CrO`=\  
1vsu[n  
SiteInfoBean siteInfoBean = null; //文件信息Bean 6}STp_x  
long[] nStartPos; //开始位置 JaFUcpZk$  
long[] nEndPos; //结束位置 eQ\jZ0s;p  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 2/EK`S  
long nFileLength; //文件长度 gWi{\x8dt  
boolean bFirst = true; //是否第一次取文件 =1/q)b,p)  
boolean bStop = false; //停止标志 zv@bI~3~  
File tmpFile; //文件下载的临时信息 U3N(cFXn  
DataOutputStream output; //输出到文件的输出流 u{P~zyx  
,02w@we5  
//负责整个文件的抓取,控制内部线程(FileSplitterFetch类) (JU_8j!  
public SiteFileFetch(SiteInfoBean bean) throws IOException [G=:?J,P  
{ 5y}BCY2=/  
siteInfoBean = bean; KqK9X  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); jiq2x\\!  
tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); 7$#rNYa,z  
if(tmpFile.exists ()) ke^d8Z.  
{ *:[b'D!A  
bFirst = false; h(|;\~  
read_nPos(); Zd+>  
} =+4 _j  
else Hh@2m\HA  
{ "4RQ`.S R  
nStartPos = new long[bean.getNSplitter()]; o"\{OX  
nEndPos = new long[bean.getNSplitter()]; p>&S7M/9  
}  -tMA  
LGfmUb-{]  
jJ c07r']  
F:,#?  
} >"b[r  
8(^ ,r#Gy  
kJ__:rS(T_  
public void run() hm6pxFkX_  
{ 'mUI-1GkT  
//获得文件长度 jNIUsM 8e  
//分割文件 j6}$+!E  
//实例FileSplitterFetch %!yxC  
//启动FileSplitterFetch线程 D$mf5G &  
//等待子线程返回 DUhT>,~]  
try{ ",QPb3  
if(bFirst) >HX)MwAP  
{ _<3r'Y,  
nFileLength = getFileSize(); M_; w %FV  
if(nFileLength == -1)  VmYBa(  
{ Qi"'bWX@  
System.err.println("File Length is not known!"); j=\Mx6os  
} ,$ mLL  
else if(nFileLength == -2) _)q4I(s*  
{ HGb.656r  
System.err.println("File is not access!"); V>r j$Nc]  
} YLigP"*~^  
else LC76Qi;|k  
{ Y!aLf[x]  
for(int i=0;i<nStartPos.length;i++) 7g8B'ex J  
{ aTX]+tBoe  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); Bqp&2zg)@  
} w0X$rl1  
for(int i=0;i<nEndPos.length-1;i++) > R#9\/s  
{ d _uF Y:  
nEndPos = nStartPos[i+1]; g*28L[Q~  
} w~n kNqm  
nEndPos[nEndPos.length-1] = nFileLength; BPqwDj W  
} m3B \)2B  
} h)P]gT0f/  
'Nw6.5  
@E YK(QS-  
//启动子线程 (]}XLMi,|!  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; $M-NR||k  
for(int i=0;i<nStartPos.length;i++) Q Y@nE  
{ j $KM9  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), "s${!A)  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), p#z;cjfSt  
nStartPos,nEndPos,i); r.9 $y/5  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8>m1UONr  
fileSplitterFetch.start(); ;}f6Y['z  
} bYK]G+Ww  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), hg{ &Y(J!U  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); M{G$Pk8[  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", jXtLo,km  
nEndPos = " + nFileLength); o;%n,S8J|^  
// fileSplitterFetch[nPos.length-1].start(); unpfA#&!"  
YyG~#6aCh  
~ J%m  
//等待子线程结束 A=W5W5l(>  
//int count = 0; \ x:_*`fU  
//是否结束while循环 ~yd%~|  
boolean breakWhile = false; XQ4dohGCP  
c_t7RWV}  
2=Jmi?k  
while(!bStop) 7f[8ED[4  
{ z(#=tC|  
write_nPos(); aam1tm#Q  
Utility.sleep(500); -}N Ab^d  
breakWhile = true; 8.PXTOhVL  
Z5yt]-WN&  
'H|;%J6d>  
for(int i=0;i<nStartPos.length;i++) s!NisF  
{ )\(lg*?:  
if(!fileSplitterFetch.bDownOver) ~T;K-9R  
{ X4XFu  
breakWhile = false; e W9)@nVJ  
break; 9DmSs=A  
} t;oT {Hge  
} G[vUOEU ~O  
if(breakWhile) a pKa4nI  
break; g<0w/n!jmC  
Ja^7$WY  
J6= w:c  
//count++; 1k*n1t):  
//if(count>4) Hxj'38Y  
// siteStop(); O\3r%=TF  
} LR hP7D+A  
R%qX_m\0  
(R,NV3m?w  
System.err.println("文件下载结束!"); \ YjB+[.  
} 3x,Aczb  
catch(Exception e){e.printStackTrace ();} 4S^  
} XryQ)x(  
@"jmI&hYn  
5?D1][  
//获得文件长度 q#l.A?rK\  
public long getFileSize() X S6]C{  
{ f2BS[$oV4  
int nFileLength = -1; 2Zv,K-G  
try{ ;GiI'M  
URL url = new URL(siteInfoBean.getSSiteURL()); nLzX Z6JlU  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); V+P8P7y37B  
httpConnection.setRequestProperty("User-Agent","NetFox"); /QV [N  
'O!Z:-qE  
n$nne6|O  
int responseCode=httpConnection.getResponseCode(); TJeou# =/  
if(responseCode>=400) H9.oVF^~  
{ S(@*3]!q  
processErrorCode(responseCode); _G_ &Me0  
return -2; //-2 represent access is error kyp U&F  
} fQ2!sV  
GZxglU,3T  
2nG{>,#C:O  
String sHeader; Sn_z  
i=,B88ko  
~ra#UG\Y8  
for(int i=1;;i++) 6RR4L^(m  
{ e);bF>.~  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); 1\M"`L/  
//Utility.log(in.readLine()); ,Zf :R  
sHeader=httpConnection.getHeaderFieldKey(i); Y*]l|)a6_]  
if(sHeader!=null) =U)n`#6_j2  
{ > u'/$ k  
if(sHeader.equals("Content-Length")) > #Grf)@"6  
{ dqIZ#;:g  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); D}=/w+  
break;  |JirBz  
} j+z'  
} AAeQ-nbP  
else R^mu%dw)(%  
break; p~v2XdR  
} ,%"\\#3S  
} 2@"0} po#  
catch(IOException e){e.printStackTrace ();} ux" D ]P  
catch(Exception e){e.printStackTrace ();} I,?Fqg'sq  
9n06n$F  
P wt ?9I  
Utility.log(nFileLength); [)C)p*!Y)  
c,b`N0dOKL  
LAu+{'O\  
return nFileLength; 0KWy?6 X  
} 3n}s CEt=  
WHhR )$zC  
zLJ:U`uh\  
//保存下载信息(文件指针位置) I@y2HxM  
private void write_nPos() R#[QoyJ  
{ ?15POY ?Z  
try{ e/m'a|%:  
output = new DataOutputStream(new FileOutputStream(tmpFile)); y<IZ|f  
output.writeInt(nStartPos.length);  tH<9  
for(int i=0;i<nStartPos.length;i++) ovo?lE-a0  
{ H4,.H,PZ  
// output.writeLong(nPos); A?6{  
output.writeLong(fileSplitterFetch.nStartPos); / h 2*$  
output.writeLong(fileSplitterFetch.nEndPos); 2@=cqD7x  
} <;TP@-a  
output.close(); ;XKo44%  
} pqGf@24c<  
catch(IOException e){e.printStackTrace ();} c_D,MW\IC  
catch(Exception e){e.printStackTrace ();} )-TeDIfm  
} 3cV+A]i  
#XYLVee,  
Jq$6$A,f  
//读取保存的下载信息(文件指针位置) >8F{lbEe  
private void read_nPos() E980yXJR  
{ )Rm 'YmO  
try{ :yFTaniJ'.  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); eEg1-  
int nCount = input.readInt(); \( Gf+  
nStartPos = new long[nCount]; 7~%  
nEndPos = new long[nCount]; Uy_}@50"l  
for(int i=0;i<nStartPos.length;i++) LB64W ;#h  
{ P?3YHa^up  
nStartPos = input.readLong(); V5(tf'  
nEndPos = input.readLong(); OyG_thX  
} 7E\K!v_  
input.close(); jl 30\M7  
} {Vt^Xc  
catch(IOException e){e.printStackTrace ();} >? A `C!i  
catch(Exception e){e.printStackTrace ();} +QCU]Fozk  
} =ihoVA:|  
(c*7VO;  
O>o}<t7  
private void processErrorCode(int nErrorCode) k:+)$[t7  
{ Xdp`Z'g  
System.err.println("Error Code : " + nErrorCode); ]Gi+Z1q  
} 2y .-4?e  
hq&  
j 44bF/  
//停止文件下载 twJ|Jmd  
public void siteStop() >X\s[d&(  
{ [M8qU$&?]  
bStop = true; xTksF?u)  
for(int i=0;i<nStartPos.length;i++)  t3yQ/  
fileSplitterFetch.splitterStop(); %gne%9nn  
E=tx.h4xG~  
\ 3js}  
} 4LKs'$:A=  
} %RT6~0z  
//负责部分文件的抓取 J!TK*\a2  
**FileSplitterFetch.java `)( <g  
*/ {TxVRpiP{Z  
package NetFox; :vgh KI  
JK'_P}[]I  
HLyFyv\  
import java.io.*; tr9_bl&z  
import java.net.*; '@}?NV0  
wYcz\uV  
+y{93nl  
public class FileSplitterFetch extends Thread { 3Av(|<cR  
&:e}4/G  
@y~BYiKs  
String sURL; //File URL ]cGz~TN~  
long nStartPos; //File Snippet Start Position j O5:{%  
long nEndPos; //File Snippet End Position ym,Ot1  
int nThreadID; //Thread's ID `Hp.%G(  
boolean bDownOver = false; //Downing is over l)!woOt  
boolean bStop = false; //Stop identical #&`WMLl+8  
FileAccessI fileAccessI = null; //File Access interface &Ow?Hd0  
,j(p}t  
luxKgcU  
public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException +<9q]V  
{ $=QGua V  
this.sURL = sURL; lj SR?:\  
this.nStartPos = nStart; KiRt'  
this.nEndPos = nEnd; @)juP- o%  
nThreadID = id; SUnmp  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 r1az=$  
} >. nt'BQ  
"<n"A7e  
/x8C70W^  
public void run() *O}'2Ht6\  
{ M]/wei"X  
while(nStartPos < nEndPos && !bStop) .V)2Tz  
{ ??e#E[bI  
OTtanJ?  
vdFQf ^l  
try{ pil*/&pB  
URL url = new URL(sURL); h C`p<jp/  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); B| 0s4E  
httpConnection.setRequestProperty("User-Agent","NetFox"); j C1^>D  
String sProperty = "bytes="+nStartPos+"-"; jv#" vQ9A]  
httpConnection.setRequestProperty("RANGE",sProperty); aXid;v,  
Utility.log(sProperty); ht74h  
d&R\7)0  
 rgvc5p  
InputStream input = httpConnection.getInputStream(); t;f p<z7N.  
//logResponseHead(httpConnection); ?[4khQt  
s:Ql](/B#  
r1[T:B'  
byte[] b = new byte[1024]; n)?F 9Wap  
int nRead; o? xR[N-J  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) bHH}x"d[x  
{ WZ V*J&  
nStartPos += fileAccessI.write(b,0,nRead); {arjW3~M:  
//if(nThreadID == 1) o-i.'L)X  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); %?G.lej,x  
} K|J#/  
@j8L{FGnN  
&7kSLat+9{  
Utility.log("Thread " + nThreadID + " is over!"); sbiDnRf  
bDownOver = true; 3SB7)8Id1  
//nPos = fileAccessI.write (b,0,nRead); /z-C :k\  
} HE<%d  
catch(Exception e){e.printStackTrace ();} r-"`Abev  
} )Jjw}}$}Y  
} (pxz#B4  
&b]KMAo3  
Z 7ZMu  
//打印回应的头信息 :V1ZeNw  
public void logResponseHead(HttpURLConnection con) l0bT_?LhK  
{ ~)CU m[:oM  
for(int i=1;;i++) Nn4Kt,KY  
{ !I+u/f?TO7  
String header=con.getHeaderFieldKey(i); 7a.#F]`  
if(header!=null) 1Y0oo jD  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); ;8xn"G0}a  
Utility.log(header+" : "+con.getHeaderField(header)); `DY4d$!4  
else OZ]3OL,  
break; F^v{Jqc  
} eOmxA<h  
} W)P_t"'@L  
#7:9XID /  
 D)eKq!_  
public void splitterStop() ?lna8]t  
{ e&7}N Za  
bStop = true; v__Go kj-  
} (C[S?@S  
,&l*AB!  
lVBy&f  
} r ($t.iS  
',ybHW%D%i  
<6@NgSFz'  
/* Oua/NF)  
**FileAccess.java jM@I"JZ b  
*//文件访问(定位,写) 2"K~:Tm#w  
package NetFox; !g:G{b  
import java.io.*; O6 J<Lqgh  
(c7{dYV  
L ]'CA^N  
public class FileAccessI implements Serializable{ 2%%U)|39mB  
aRKG)0=  
//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 WC&Ltw8  
RandomAccessFile oSavedFile; ,<WykeC  
long nPos; lMf5F8  
, &f20o  
)8>f  
public FileAccessI() throws IOException O g~"+IGp  
{ {8Nd-WJ{  
this("",0); lGgKzi9VD  
} c{P`oB8  
W n mRRq^  
;rdLYmmx^  
public FileAccessI(String sName,long nPos) throws IOException ]lG\t'R  
{ &otgN<H9  
oSavedFile = new RandomAccessFile(sName,"rw"); i58CA?  
this.nPos = nPos; Yx/~8K_%M?  
oSavedFile.seek(nPos); .`=PE&xq  
}  } R6h  
j_<n~ri-  
D[y|y 3F  
public synchronized int write(byte[] b,int nStart,int nLen) 3&2q\]Y,  
{ P@? '@.e  
int n = -1; } dlNMW  
try{ ?uBC{KQ}Y  
oSavedFile.write(b,nStart,nLen); /Bu5k BC  
n = nLen; };sm8P{M  
} ~"B[6^sW  
catch(IOException e) s*WfRY*=V  
{ /T(~T  
e.printStackTrace (); k&;L(D  
} 6>A8#VT  
} ~bOP^'  
ar}759  
return n; -"L6^IH7  
} >k-poBw  
:Djp\ e6!  
SSC!BcC1  
} MUl+Oy>  
b=l}|)a  
]TOY_K8"z#  
/* VX%\_@  
**SiteInfoBean.java /L Tyiiz6  
*/ 6K0*?j{;"  
package NetFox; nClU 5  
&|;!St]!M  
xK ux5u _  
public class SiteInfoBean { ".Ug A\0  
wQ.zj`?$(  
Zt=X %M|aw  
private String sSiteURL; //Site's URL 9q{dRS[A  
private String sFilePath; //Saved File's Path |7fBiVo  
private String sFileName; //Saved File's Name XITQB|C??$  
private int nSplitter; //Count of Splited Downloading File u'> CU  
1 j8,Zrg1  
,:,|A/U  
public SiteInfoBean() 9] \vw  
{//nSplitter的缺省值为5 5+Ut]AL5  
//default value of nSplitter is 5 n|6yz[N  
this("","","",5); K.7gd1I  
} `9gx-')]\  
jm"xf7  
_v,n~a}&  
public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) g5[3[Z(.  
{ vt,X:3  
sSiteURL= sURL; Kwnu|8  
sFilePath = sPath; ~3 (>_r  
sFileName = sName; ^" -2fJ  
this.nSplitter = nSpiltter; ma~`&\xE  
"$Q Gifb  
^Pwq`G A  
} VGIc|Q=F  
>MH@FnUL  
"{lnSLk  
public String getSSiteURL() jL$X3QS:  
{ * PPFk.#x  
return sSiteURL; 1[ Pbsb  
} Q1yTDJ(2  
C5z4%,`f  
i/Z5/(zF  
public void setSSiteURL(String value) *UC^&5:  
{ na)_8r~  
sSiteURL = value; <^paRKEa+#  
} {HeMdGn9  
kOO2 ?L|Z  
cs)hq4-L`  
public String getSFilePath() 2]wh1)  
{ ]&>)=b!,  
return sFilePath; #96a7K  
} Y*f<\z(4  
LTHS&3% 2  
S;~_9i]upe  
public void setSFilePath(String value) F(r &:3!97  
{ V96BtV sB  
sFilePath = value; S"l&=J2dc  
} teb(\% ,  
 VM`."un]  
 f63q  
public String getSFileName() KtE`L4tW6  
{ /~:ztv\$M"  
return sFileName; 78wcMQNX9  
} Kt(p|  
q$P"o].EK  
_U %B1s3y  
public void setSFileName(String value) @z.!Dby  
{ t{9Ph]e  
sFileName = value; r%4:,{HF  
} "P~>AXcq  
CAO$Zt  
M=%p$\x  
public int getNSplitter() 6._):[_2  
{ .jU9{;[  
return nSplitter; H b.oKo$T  
} bmLNR  
A|^?.uIM  
u CXd% CzE  
public void setNSplitter(int nCount) :>=,sLfJ  
{  NNX/2  
nSplitter = nCount; _>.%X45xi  
} (,>`\\  
} bc-"If Z&  
_" n4SXhq  
|Cm}%sgR\0  
/* 4p]Y`];U  
**Utility.java %{Gqhb=u\  
*/ 5"+* c@L  
package NetFox; i~4Kek6,I  
S1."2AxO  
s*;~CH-[  
public class Utility { UOyP6ej  
HhO$`YZ%>  
8wOr`ho B  
public Utility() ]?2AFkF  
{ XB?!V|bno  
I`|>'$E[r  
4dO>L"  
} u4Sa4o  
v'uQ'CiH  
//线程睡眠 IKt9=Tx  
public static void sleep(int nSecond) D~<GVp5T  
{ fN9hBC@  
try{ 2-]m#}zbP  
Thread.sleep(nSecond); {)+/w"^.  
} >z2 {D7  
catch(Exception e) -v:Y\=[\  
{ ${?Px c{-  
e.printStackTrace (); ZISR]xay  
} ;-3M  
} W$y?~2  
"H({kmR  
//日志 x-"7{@lz  
public static void log(String sMsg) N4Ym[l  
{ eWFlJ;=  
System.err.println(sMsg); z}5XLa^  
} \%K6T)9  
9X-DR  
=LC5o2bLy  
public static void log(int sMsg) = #`FXO1C  
{ Q{%ow:;s*  
System.err.println(sMsg); lm+wjhkN  
} `bi5#xR  
} GRNH!:e  
yfU1;MI  
|1neCP@ng  
/* E^  rN)  
**TestMethod.java rkD(K G9E  
*/ %Z.!Bm:  
package NetFox; EV}%D9:  
Xd4~N:  
D=8=wT2 <  
public class TestMethod { f~53:;L/  
bY`k`3v  
E yNCky  
public TestMethod() /<n_X:[)  
{ ///xx/weblogic60b2_win.exe Fax73vl|^a  
try{ u`ZnxD>  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); =Vi+wH{xM  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); , vR4x:W  
SiteFileFetch fileFetch = new SiteFileFetch(bean); }\9qN!ol  
fileFetch.start(); Q5Wb)  
} ]UNmhF!W>u  
catch(Exception e){e.printStackTrace ();} 5EU3BVu&u  
B%,0zb+-L  
Aoj X)_"z  
} 4|~o<t8  
(|WqOwmoUt  
8.vD]hO  
public static void main(String[] args) ^*ZO@GNL  
{ 0_ ;-QAd  
new TestMethod(); |{$Vk%cUE  
} H.YntFtD'  
} #e=[W))  
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