PostgreSQL数据库 连接JAVA

1、导入jar包

https://jdbc.postgresql.org/download.html

在这个里面去下载你所需要的jar包；直接复制粘贴到eclipse里的WEB-INF下的lib里面。

2、连接数据库

package collection;

import java.sql.Connection;
import java.sql.DriverManager;

public class PostgreSQLJDBC {
	   public static void main(String args[]) {
		   //连接
	      Connection c = null;
	      try {
	    	  //加载数据驱动，数据库
	         Class.forName("org.postgresql.Driver");
	         //连接数据库地址、名称、密码
	         c = DriverManager
	            .getConnection("jdbc:postgresql://127.0.0.1:5432/demo",
	            "postgres", "xxx");
	      } catch (Exception e) {
	         e.printStackTrace();
	         //err是运行期异常和错误反馈的输出流的方向
	         System.err.println(e.getClass().getName()+": "+e.getMessage());
	         //调用exit(0)方法终止虚拟机也就是退出你的Java程序，括号里面的是参数，进程结束的返回值。
	         System.exit(0);
	      }
	      //输出 打开数据库成功
	      System.out.println("Opened database successfully");
	   }
	}

3、创建数据库

package collection;


import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;


/**
 * 创建表
 * @author Administrator
 *
 */
public class CreateTable {
	
	public static void main(String[] args) throws Exception {
		//连接数据库
		Connection c = null;
		//将 SQL 语句发送到数据库中
		Statement stmt = null;
		
		try {
			//加载数据驱动，数据库
			Class.forName("org.postgresql.Driver");
			//地址，用户名，密码
			c = DriverManager.getConnection(
					"jdbc:postgresql://127.0.0.1:5432/demo", "postgres", "xxx");	
			System.out.println("Opened database successfully");
			
			//Statement stmt = conn.createStatement();
			//将 SQL 语句发送到数据库中
	        stmt = c.createStatement();
	        //sql语句的输入
	        String sql = "CREATE TABLE BBQ " +
                    "(ID INT PRIMARY KEY     NOT NULL," +
                    " NAME           TEXT    NOT NULL, " +
                    " AGE            INT     NOT NULL, " +
                    " ADDRESS        CHAR(50), " +
                    " SALARY         REAL)";
	        stmt.executeUpdate(sql);
	        stmt.close();
	        c.close();
       } catch ( Exception e ) {
         System.err.println( e.getClass().getName()+": "+ e.getMessage() );
         System.exit(0);
       }
       System.out.println("Table created successfully");
     }
}

4、插入数据库

package collection;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;

public class InsertTable {
	
	public static void main(String[] args) throws Exception {
		Connection c = null;
		Statement stmt = null;
		
		try {
			//加载数据驱动，数据库
			Class.forName("org.postgresql.Driver");
			//连接数据库地址、名称、密码
			c = DriverManager.getConnection(
					"jdbc:postgresql://127.0.0.1:5432/demo", "postgres", "xxx");
			//当我们进行多条数据进行增删改的时候，一旦在一句sql中出现了错误，
			//就会出现有部分数据已经成功，而后面的数据就没有办法执行，这个时候，就会出现脏数据。
			//因此我们使用setAutoCommit方法，这个方法有一个参数，参数值为Boolean，
			//当true的时候可启用自动提交模式，false可禁用该模式。
			c.setAutoCommit(false);
			System.out.println("Opened database successfully");
			
			stmt = c.createStatement();
			String sql = 
					"INSERT INTO BBQ(ID,NAME,AGE,ADDRESS)" 
			+ "VALUES(1,'CXM',22,'bj');";
			stmt.executeUpdate(sql);
			
			sql = "INSERT INTO BBQ (ID,NAME,AGE,ADDRESS) "
	               + "VALUES (2, 'Allen', 25, 'Texas');";
	         stmt.executeUpdate(sql);

	         sql = "INSERT INTO BBQ (ID,NAME,AGE,ADDRESS) "
	               + "VALUES (3, 'Teddy', 23, 'Norway');";
	         stmt.executeUpdate(sql);

	         sql = "INSERT INTO BBQ (ID,NAME,AGE,ADDRESS) "
	               + "VALUES (4, 'Mark', 25, 'Rich-Mond ');";
	         stmt.executeUpdate(sql);

			stmt.close();
			c.commit();
			c.close();
		} catch (ClassNotFoundException e) {
			System.err.println( e.getClass().getName()+": "+ e.getMessage() );
	        System.exit(0);
		}
		
		 System.out.println("Records created successfully");
	}
	
}

5、更新数据库

package collection;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class UpdateTable {
	
	public static void main(String[] args) throws Exception {
		
		Connection c = null;
		Statement stat = null;
		
		try {
			//加载数据驱动，数据库
			Class.forName("org.postgresql.Driver");
			//连接数据库地址、名称、密码
			c= DriverManager
					.getConnection("jdbc:postgresql://127.0.0.1:5432/demo", "postgres", "xxx");
			c.setAutoCommit(false);
			System.out.println("Opened database successfully");
			
			stat = c.createStatement();
			String sql = "UPDATE BBQ SET AGE=15 WHERE ID=2 ;";
			stat.executeUpdate(sql);
			c.commit();
			
			//查询数据库
			ResultSet rs = stat.executeQuery("SELECT * FROM BBQ;");
			while ( rs.next() ) {
	            int id = rs.getInt("id");
	            String  name = rs.getString("name");
	            int age  = rs.getInt("age");
	            String  address = rs.getString("address");
	            System.out.println( "ID = " + id );
	            System.out.println( "NAME = " + name );
	            System.out.println( "AGE = " + age );
	            System.out.println( "ADDRESS = " + address );
	            System.out.println();
	         }
			rs.close();
			stat.close();
			c.close();
		} catch (ClassNotFoundException e) {
			System.err.println( e.getClass().getName()+": "+ e.getMessage() );
	        System.exit(0);
		}
		System.out.println("Operation done successfully");
	}

}

6、删除数据库

package collection;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class DeleteTable {
	public static void main( String args[] )
    {
		//连接数据库
		Connection c = null;
		//将 SQL 语句发送到数据库中
		Statement stmt = null;
      try {
    	  //加载数据驱动，数据库
    	  Class.forName("org.postgresql.Driver");
    	  //连接数据库地址、名称、密码
        c = DriverManager
           .getConnection("jdbc:postgresql://127.0.0.1:5432/demo",
	            "postgres", "xxx");
        c.setAutoCommit(false);
        System.out.println("Opened database successfully");

        stmt = c.createStatement();
        String sql = "DELETE from COMPANY where ID=2;";
        stmt.executeUpdate(sql);
        c.commit();

        //查询数据库表
        ResultSet rs = stmt.executeQuery( "SELECT * FROM BBQ;" );
        while ( rs.next() ) {
           int id = rs.getInt("id");
           String  name = rs.getString("name");
           int age  = rs.getInt("age");
           String  address = rs.getString("address");
           System.out.println( "ID = " + id );
           System.out.println( "NAME = " + name );
           System.out.println( "AGE = " + age );
           System.out.println( "ADDRESS = " + address );
           System.out.println();
        }
        //关闭
        rs.close();
        stmt.close();
        c.close();
      } catch ( Exception e ) {
        System.err.println( e.getClass().getName()+": "+ e.getMessage() );
        System.exit(0);
      }
      System.out.println("Operation done successfully");
    }

}

有参考其他的资料！！