java从mysql导出数据的具体实例

时间:2021-05-19

复制代码 代码如下:
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;


public class TestDB {

public static void main(String[] args) {


//Test(); // 生成测试数据
//Exp();
Exp(0);
//System.out.println(readText("/opt/id.txt"));
}

/**
* 导出数据
*/
public static void Exp() {

Connection Conn=null;

try {


Class.forName("com.mysql.jdbc.Driver").newInstance();
String jdbcUrl = "jdbc:mysql://127.0.0.1:3306/test?characterEncoding=GBK";
//String jdbcUsername = "root";
//String jdbcPassword = "mysql";
Conn = DriverManager.getConnection(jdbcUrl, "root", "mysql");

System.out.println("conn"+Conn);

Exp(Conn);

} catch (SQLException e) {
e.printStackTrace();
}
catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally
{

try {
Conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}

public static void Exp(int startid) {

Connection Conn=null;

try {

Class.forName("com.mysql.jdbc.Driver").newInstance();
String jdbcUrl = "jdbc:mysql://127.0.0.1:3306/test?characterEncoding=GBK";
String jdbcUsername = "root";
String jdbcPassword = "mysql";
Conn = DriverManager.getConnection(jdbcUrl, jdbcUsername, jdbcPassword);

System.out.println("conn"+Conn);

Exp(Conn,startid);

} catch (SQLException e) {
e.printStackTrace();
}
catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally
{

try {
Conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}

/**
* 导出从startid开始的数据
* @param conn
* @param start_id
*/
public static void Exp(Connection conn,int start_id) {

int counter = 0;
int startid=start_id;
boolean flag = true;
while (flag) {
flag = false;
String Sql = "SELECT * FROM t_test WHERE id>"
+ startid + " order by id asc LIMIT 50";

System.out.println("sql===" + Sql);
try {
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(Sql);

while (rs.next()) {
flag = true;
int id = rs.getInt("id");
String title = rs.getString("title");
startid = id ;

counter++;

writeContent(counter+"--id--"+id+"--title-"+title+"\r\n", "D:\\","log.txt",true);

System.out.println("i="+counter+"--id--"+id+"--title-"+title);

}
rs.close();
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

writeContent(""+startid, "D:\\","id.txt",false);

}

/**
* 导出一小时内的数据
* @param conn
*/

public static void Exp(Connection conn) {

int counter = 0;
//一小时内的数据
Long timestamp = System.currentTimeMillis() - (600 * 60 * 1000);
boolean flag = true;
while (flag) {
flag = false;
String Sql = "SELECT * FROM t_test WHERE createTime>"
+ timestamp + " LIMIT 50";

System.out.println("sql===" + Sql);
try {
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery(Sql);
while (rs.next()) {
flag = true;
int id = rs.getInt("id");
String title = rs.getString("title");
Long lastmodifytime = rs.getLong("createTime");
timestamp = lastmodifytime;

counter++;

System.out.println("i="+counter+"--id--"+id+"--title-"+title);

}
rs.close();
stmt.close();
} catch (SQLException e) {
e.printStackTrace();
}
}

}


public static void Test() {

Connection Conn=null;

try {

Class.forName("com.mysql.jdbc.Driver").newInstance();
String jdbcUrl = "jdbc:mysql://127.0.0.1:3306/test?characterEncoding=GBK";
String jdbcUsername = "root";
String jdbcPassword = "mysql";
Conn = DriverManager.getConnection(jdbcUrl, jdbcUsername, jdbcPassword);

System.out.println("conn"+Conn);

for(int i=1;i<=10000;i++)
{
add(Conn,"testTitle"+i+"-"+System.currentTimeMillis());
}

} catch (SQLException e) {
e.printStackTrace();
}
catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally
{

try {
Conn.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}

public static void add(Connection conn,String title)
{
PreparedStatement pstmt = null;
String insert_sql = "insert into t_test(title,createTime) values (?,?)";

System.out.println("sql="+insert_sql);
try {
pstmt = conn.prepareStatement(insert_sql);
pstmt.setString(1,title);
pstmt.setLong(2,System.currentTimeMillis());
int ret = pstmt.executeUpdate();

} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally{
try {
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}

/**
* 写入内容到文件
*
* @param number
* @param filename
* @return
*/
public static boolean writeContent(String c, String dirname,String filename,boolean isAppend) {

File f=new File(dirname);
if (!f.exists())
{
f.mkdirs();
}

try {
FileOutputStream fos = new FileOutputStream( dirname+File.separator+filename,isAppend);
OutputStreamWriter writer = new OutputStreamWriter(fos);
writer.write(c);
writer.close();
fos.close();
} catch (IOException e) {
e.printStackTrace();
return false;
}
return true;
}


/**
* 从文件读取内容
*
* @param filename
* @return
*/
public static String readText(String filename) {
String content = "";
try {
File file = new File(filename);
if (file.exists()) {
FileReader fr = new FileReader(file);
BufferedReader br = new BufferedReader(fr);
String str = "";
String newline = "";
while ((str = br.readLine()) != null) {
content += newline + str;
newline = "\n";
}
br.close();
fr.close();
}
} catch (IOException e) {
e.printStackTrace();
}
return content;
}
}

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