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JDBC系列教程之十一：其他的几个API

2019-03-28 00:11|来源: 领悟书生

其他的几个API

l PreparedStatement.getGeneratedKeys()

PreparedStatementps = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);

ps.executeUpdate();

ResultSetrs = st.getGeneratedKeys();rs.getInt(1);

l 批处理，可以大幅度提升大量增、删、改的速度。

PreparedStatement.addBatch();

PreparedStatement.executeBatch();

BatchTest.java

static void createBatch() throws SQLException {

Connection conn = null;

PreparedStatement ps = null;

ResultSet rs = null;

try {

conn = JdbcUtils.getConnection();

String sql = "insert into user(name,birthday, money) values (?, ?, ?) ";

ps = conn.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);

for (int i = 0; i < 100; i++) {

ps.setString(1, "name" + i);

ps.setDate(2, new Date(System.currentTimeMillis()));

ps.setFloat(3, 100f + i);

//批量

ps.addBatch();

}

int[] is = ps.executeBatch();

} finally {

JdbcUtils.free(rs, ps, conn);

}

l 可滚动的结果集

Statementst =

connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);

ResultSetrs = st.executeQuery(sql);

rs.beforeFirst();rs.afterLast();rs.first();rs.isFirst();rs.last();rs.isLast();

rs.absolute(9);rs.moveToInsertRow();

可滚动结果集与分页技术ScrollTest.java

package com.hyneng.jdbc;

import java.sql.Connection;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

/**

* 2010-10-08

* @author HuangYineng

public class ScrollTest {

public static void main(String[] args) throws SQLException {

scroll();

}

static void scroll() throws SQLException {

Connection conn = null;

Statement st = null;

ResultSet rs = null;

try {

// 2.建立连接

conn = JdbcUtils.getConnection();

st = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,

ResultSet.CONCUR_READ_ONLY);

// rs = st.executeQuery("select id, name, money, birthday from user where id<10");

//分页，从150条开始，取10条

rs = st.executeQuery("select id, name, money, birthday from user limit 150, 10");

while (rs.next()) {

System.out.println(rs.getObject("id") + "\t"

+ rs.getObject("name") + "\t"

+ rs.getObject("birthday") + "\t"

+ rs.getObject("money"));

}

System.out.println("------------");

//固定到哪一行

rs.absolute(150);

int i = 0;

while (rs.next() && i < 10) {

i++;

System.out.println(rs.getObject("id") + "\t"

+ rs.getObject("name") + "\t"

+ rs.getObject("birthday") + "\t"

+ rs.getObject("money"));

}

// if (rs.previous())

// System.out.println(rs.getObject("id") + "\t"

// + rs.getObject("name") + "\t"

// + rs.getObject("birthday") + "\t"

// + rs.getObject("money"));

} finally {

JdbcUtils.free(rs, st, conn);

}

l 可更新的结果集

conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,

ResultSet.CONCUR_UPDATABLE);

rs.updateString("colname", "new value");

rs.updateRow();

OtherApi---read()

static void read() throws SQLException, InterruptedException {

Connection conn = null;

Statement st = null;

ResultSet rs = null;

try {

// 2.建立连接

conn = JdbcUtils.getConnection();

// 3.创建语句

st = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,

ResultSet.CONCUR_UPDATABLE);

// 4.执行语句

rs = st.executeQuery("select id, name, money, birthday from user where id < 5");

// 5.处理结果

while (rs.next()) {

int id = rs.getInt("id");

System.out.println("show " + id + "...");

Thread.sleep(10000);

System.out.println(id + "\t" + rs.getObject("name") + "\t"

+ rs.getObject("birthday") + "\t"

+ rs.getObject("money"));

}

} finally {

JdbcUtils.free(rs, st, conn);

}

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