JDBC2

1.JDBC鏈接池

public class JdbcTemplateDemo2 {

    //Junit單元測試，可讓方法獨立執行


    //1. 獲取JDBCTemplate對象
    private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());
    /**
     * 1. 修改1號數據的 salary 爲 10000
     */
    @Test
    public void test1(){

        //2. 定義sql
        String sql = "update emp set salary = 10000 where id = 1001";
        //3. 執行sql
        int count = template.update(sql);
        System.out.println(count);
    }

    /**
     * 2. 添加一條記錄
     */
    @Test
    public void test2(){
        String sql = "insert into emp(id,ename,dept_id) values(?,?,?)";
        int count = template.update(sql, 1015, "郭靖", 10);
        System.out.println(count);

    }

    /**
     * 3.刪除剛纔添加的記錄
     */
    @Test
    public void test3(){
        String sql = "delete from emp where id = ?";
        int count = template.update(sql, 1015);
        System.out.println(count);
    }

    /**
     * 4.查詢id爲1001的記錄，將其封裝爲Map集合
     * 注意：這個方法查詢的結果集長度只能是1
     */
    @Test
    public void test4(){
        String sql = "select * from emp where id = ? or id = ?";
        Map<String, Object> map = template.queryForMap(sql, 1001,1002);
        System.out.println(map);
        //{id=1001, ename=孫悟空, job_id=4, mgr=1004, joindate=2000-12-17, salary=10000.00, bonus=null, dept_id=20}

    }

    /**
     * 5. 查詢全部記錄，將其封裝爲List
     */
    @Test
    public void test5(){
        String sql = "select * from emp";
        List<Map<String, Object>> list = template.queryForList(sql);

        for (Map<String, Object> stringObjectMap : list) {
            System.out.println(stringObjectMap);
        }
    }

    /**
     * 6. 查詢全部記錄，將其封裝爲Emp對象的List集合
     */

    @Test
    public void test6(){
        String sql = "select * from emp";
        List<Emp> list = template.query(sql, new RowMapper<Emp>() {

            @Override
            public Emp mapRow(ResultSet rs, int i) throws SQLException {
                Emp emp = new Emp();
                int id = rs.getInt("id");
                String ename = rs.getString("ename");
                int job_id = rs.getInt("job_id");
                int mgr = rs.getInt("mgr");
                Date joindate = rs.getDate("joindate");
                double salary = rs.getDouble("salary");
                double bonus = rs.getDouble("bonus");
                int dept_id = rs.getInt("dept_id");

                emp.setId(id);
                emp.setEname(ename);
                emp.setJob_id(job_id);
                emp.setMgr(mgr);
                emp.setJoindate(joindate);
                emp.setSalary(salary);
                emp.setBonus(bonus);
                emp.setDept_id(dept_id);

                return emp;
            }
        });


        for (Emp emp : list) {
            System.out.println(emp);
        }
    }

    /**
     * 6. 查詢全部記錄，將其封裝爲Emp對象的List集合
     */

    @Test
    public void test6_2(){
        String sql = "select * from emp";
        List<Emp> list = template.query(sql, new BeanPropertyRowMapper<Emp>(Emp.class));
        for (Emp emp : list) {
            System.out.println(emp);
        }
    }

    /**
     * 7. 查詢總記錄數
     */

    @Test
    public void test7(){
        String sql = "select count(id) from emp";
        Long total = template.queryForObject(sql, Long.class);
        System.out.println(total);
    }

}

/**
 * Druid鏈接池的工具類
 */
public class JDBCUtils {

    //1.定義成員變量 DataSource
    private static DataSource ds ;

    static{
        try {
            //1.加載配置文件
            Properties pro = new Properties();
            pro.load(JDBCUtils.class.getClassLoader().getResourceAsStream("druid.properties"));
            //2.獲取DataSource
            ds = DruidDataSourceFactory.createDataSource(pro);
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 獲取鏈接
     */
    public static Connection getConnection() throws SQLException {
        return ds.getConnection();
    }

    /**
     * 釋放資源
     */
    public static void close(Statement stmt,Connection conn){
       /* if(stmt != null){
            try {
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        if(conn != null){
            try {
                conn.close();//歸還鏈接
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }*/

       close(null,stmt,conn);
    }


    public static void close(ResultSet rs , Statement stmt, Connection conn){


        if(rs != null){
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }


        if(stmt != null){
            try {
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }

        if(conn != null){
            try {
                conn.close();//歸還鏈接
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 獲取鏈接池方法
     */

    public static DataSource getDataSource(){
        return  ds;
    }

}

driverClassName=com.mysql.jdbc.Driver
url=jdbc:mysql:///db3
username=root
password=root
# 初始化鏈接數量
initialSize=5
# 最大鏈接數
maxActive=10
# 最大等待時間
maxWait=3000

2.JDBC druid鏈接池

/**
 * 使用新的工具類
 */
public class DruidDemo2 {

    public static void main(String[] args) {
        /*
         * 完成添加操做：給account表添加一條記錄
         */
        Connection conn = null;
        PreparedStatement pstmt = null;
        try {
            //1.獲取鏈接
            conn = JDBCUtils.getConnection();
            //2.定義sql
            String sql = "insert into account values(null,?,?)";
            //3.獲取pstmt對象
            pstmt = conn.prepareStatement(sql);
            //4.給？賦值
            pstmt.setString(1,"王五");
            pstmt.setDouble(2,3000);
            //5.執行sql
            int count = pstmt.executeUpdate();
            System.out.println(count);
        } catch (SQLException e) {
            e.printStackTrace();
        }finally {
            //6. 釋放資源
            JDBCUtils.close(pstmt,conn);
        }
    }

}

/**
 * Druid演示
 */
public class DruidDemo {
    public static void main(String[] args) throws Exception {
        //1.導入jar包
        //2.定義配置文件
        //3.加載配置文件
        Properties pro = new Properties();
        InputStream is = DruidDemo.class.getClassLoader().getResourceAsStream("druid.properties");
        pro.load(is);
        //4.獲取鏈接池對象
        DataSource ds = DruidDataSourceFactory.createDataSource(pro);
        //5.獲取鏈接
        Connection conn = ds.getConnection();
        System.out.println(conn);

    }
}

3.JDBC c3po鏈接池

/**
 * c3p0的演示
 */
public class C3P0Demo1 {
    public static void main(String[] args) throws SQLException {
        //1.建立數據庫鏈接池對象
        DataSource ds  = new ComboPooledDataSource();
        //2. 獲取鏈接對象
        Connection conn = ds.getConnection();

        //3. 打印
        System.out.println(conn);

    }
}

/**
 * c3p0的演示
 */
public class C3P0Demo1 {
    public static void main(String[] args) throws SQLException {
        //1.建立數據庫鏈接池對象
        DataSource ds  = new ComboPooledDataSource();
        //2. 獲取鏈接對象
        Connection conn = ds.getConnection();

        //3. 打印
        System.out.println(conn);

    }
}

 

<c3p0-config>
  <!-- 使用默認的配置讀取鏈接池對象 -->
  <default-config>
      <!--  鏈接參數 -->
    <property name="driverClass">com.mysql.jdbc.Driver</property>
    <property name="jdbcUrl">jdbc:mysql://localhost:3306/db4</property>
    <property name="user">root</property>
    <property name="password">root</property>
    
    <!-- 鏈接池參數 -->
    <!--初始化申請的鏈接數量-->
    <property name="initialPoolSize">5</property>
    <!--最大的鏈接數量-->
    <property name="maxPoolSize">10</property>
    <!--超時時間-->
    <property name="checkoutTimeout">3000</property>
  </default-config>

  <named-config name="otherc3p0"> 
    <!--  鏈接參數 -->
    <property name="driverClass">com.mysql.jdbc.Driver</property>
    <property name="jdbcUrl">jdbc:mysql://localhost:3306/db3</property>
    <property name="user">root</property>
    <property name="password">root</property>
    
    <!-- 鏈接池參數 -->
    <property name="initialPoolSize">5</property>
    <property name="maxPoolSize">8</property>
    <property name="checkoutTimeout">1000</property>
  </named-config>
</c3p0-config>