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(三)JDBC之使用Statement,PreparedStatement,ResultSet

2013-04-15 09:56 239 查看
1. 创建一个获取Connection对象和关闭资源的工具类

  在对数据库进行CRUD操作的时候,每一个操作都需要获取Connection对象,所以我们就可以把获取Connection对象的过程抽离到一个工具类当中,下面是具体代码。

  

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public class CRUD {

public static void main(String[] args) throws SQLException {
// create();
read();
// update();
// delete();
}

static void delete() throws SQLException {
Connection conn = null;
Statement st = null;
ResultSet rs = null;
try {
// 2.建立连接
conn = JdbcUtils.getConnection();
// conn = JdbcUtilsSing.getInstance().getConnection();
// 3.创建语句
st = conn.createStatement();

String sql = "delete from user where id>4";

// 4.执行语句
int i = st.executeUpdate(sql);

System.out.println("i=" + i);
} finally {
JdbcUtils.free(rs, st, conn);
}
}

static void update() throws SQLException {
Connection conn = null;
Statement st = null;
ResultSet rs = null;
try {
// 2.建立连接
conn = JdbcUtils.getConnection();
// conn = JdbcUtilsSing.getInstance().getConnection();
// 3.创建语句
st = conn.createStatement();

String sql = "update user set money=money+10 ";

// 4.执行语句
int i = st.executeUpdate(sql);

System.out.println("i=" + i);
} finally {
JdbcUtils.free(rs, st, conn);
}
}

static void create() throws SQLException {
Connection conn = null;
Statement st = null;
ResultSet rs = null;
try {
// 2.建立连接
conn = JdbcUtils.getConnection();
// conn = JdbcUtilsSing.getInstance().getConnection();
// 3.创建语句
st = conn.createStatement();

String sql = "insert into user(name,birthday, money) values ('name1', '1987-01-01', 400) ";

// 4.执行语句
int i = st.executeUpdate(sql);

System.out.println("i=" + i);
} finally {
JdbcUtils.free(rs, st, conn);
}
}

static void read() throws SQLException {
Connection conn = null;
Statement st = null;
ResultSet rs = null;
try {
// 2.建立连接
conn = JdbcUtils.getConnection();
// conn = JdbcUtilsSing.getInstance().getConnection();
// 3.创建语句
st = conn.createStatement();

// 4.执行语句
rs = st.executeQuery("select id, name, money, birthday  from user");

// 5.处理结果
while (rs.next()) {
System.out.println(rs.getObject("id") + "\t"
+ rs.getObject("name") + "\t"
+ rs.getObject("birthday") + "\t"
+ rs.getObject("money"));
}
} finally {
JdbcUtils.free(rs, st, conn);
}
}

}
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