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JDBC.java
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485 lines (436 loc) · 13.3 KB
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public void save(Student stu){
String sql="INSERT INTO t_student(name,age) VALUES(?,?)";
Connection conn=null;
Statement st=null;
try{
// 1. 加载注册驱动
Class.forName("com.mysql.jdbc.Driver");
// 2. 获取数据库连接
conn=DriverManager.getConnection("jdbc:mysql:///jdbcdemo","root","root");
// 3. 创建语句对象
PreparedStatement ps=conn.prepareStatement(sql);
ps.setObject(1,stu.getName());
ps.setObject(2,stu.getAge());
// 4. 执行SQL语句
ps.executeUpdate();
// 5. 释放资源
}catch(Exception e){
e.printStackTrace();
}finally{
try{
if(st!=null)
st.close();
}catch(SQLException e){
e.printStackTrace();
}finally{
try{
if(conn!=null)
conn.close();
}catch(SQLException e){
e.printStackTrace();
}
}
}
}
// 删除学生信息
public void delete(Long id){
String sql="DELETE FROM t_student WHERE id=?";
Connection conn=null;
Statement st=null;
try{
// 1. 加载注册驱动
Class.forName("com.mysql.jdbc.Driver");
// 2. 获取数据库连接
conn=DriverManager.getConnection("jdbc:mysql:///jdbcdemo","root","root");
// 3. 创建语句对象
PreparedStatement ps=conn.prepareStatement(sql);
ps.setObject(1,id);
// 4. 执行SQL语句
ps.executeUpdate();
// 5. 释放资源
}catch(Exception e){
e.printStackTrace();
}finally{
try{
if(st!=null)
st.close();
}catch(SQLException e){
e.printStackTrace();
}finally{
try{
if(conn!=null)
conn.close();
}catch(SQLException e){
e.printStackTrace();
}
}
}
}
// 修改学生信息
public void update(Student stu){
String sql="UPDATE t_student SET name=?,age=? WHERE id=?";
Connection conn=null;
Statement st=null;
try{
// 1. 加载注册驱动
Class.forName("com.mysql.jdbc.Driver");
// 2. 获取数据库连接
conn=DriverManager.getConnection("jdbc:mysql:///jdbcdemo","root","root");
// 3. 创建语句对象
PreparedStatement ps=conn.prepareStatement(sql);
ps.setObject(1,stu.getName());
ps.setObject(2,stu.getAge());
ps.setObject(3,stu.getId());
// 4. 执行SQL语句
ps.executeUpdate();
// 5. 释放资源
}catch(Exception e){
e.printStackTrace();
}finally{
try{
if(st!=null)
st.close();
}catch(SQLException e){
e.printStackTrace();
}finally{
try{
if(conn!=null)
conn.close();
}catch(SQLException e){
e.printStackTrace();
}
}
}
}
//工具类
public class JdbcUtil {
private JdbcUtil() { }
static {
// 1. 加载注册驱动
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (Exception e) {
e.printStackTrace();
}
}
public static Connection getConnection() {
try {
// 2. 获取数据库连接
return DriverManager.getConnection("jdbc:mysql:///jdbcdemo", "root", "root");
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
//释放资源
public static void close(ResultSet rs, Statement st, Connection conn) {
try {
if (rs != null)
rs.close();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
if (st != null)
st.close();
} catch (SQLException e) {
e.printStackTrace();
} finally {
try {
if (conn != null)
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}
}
}
// 增加学生信息
public void save(Student stu) {
String sql = "INSERT INTO t_student(name,age) VALUES(?,?)";
Connection conn = null;
PreparedStatement ps=null;
try {
conn = JDBCUtil.getConnection();
// 3. 创建语句对象
ps = conn.prepareStatement(sql);
ps.setObject(1, stu.getName());
ps.setObject(2, stu.getAge());
// 4. 执行SQL语句
ps.executeUpdate();
// 5. 释放资源
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCUtil.close(null, ps, conn);
}
}
// 删除学生信息
public void delete(Long id) {
String sql = "DELETE FROM t_student WHERE id=?";
Connection conn = null;
PreparedStatement ps = null;
try {
conn=JDBCUtil.getConnection();
// 3. 创建语句对象
ps = conn.prepareStatement(sql);
ps.setObject(1, id);
// 4. 执行SQL语句
ps.executeUpdate();
// 5. 释放资源
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCUtil.close(null, ps, conn);
}
}
// 修改学生信息
public void update(Student stu) {
String sql = "UPDATE t_student SET name=?,age=? WHERE id=?";
Connection conn = null;
PreparedStatement ps = null;
try {
conn=JDBCUtil.getConnection();
// 3. 创建语句对象
ps = conn.prepareStatement(sql);
ps.setObject(1, stu.getName());
ps.setObject(2, stu.getAge());
ps.setObject(3, stu.getId());
// 4. 执行SQL语句
ps.executeUpdate();
// 5. 释放资源
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCUtil.close(null, ps, conn);
}
}
public Student get(Long id) {
String sql = "SELECT * FROM t_student WHERE id=?";
Connection conn = null;
Statement st = null;
ResultSet rs = null;
PreparedStatement ps=null;
try {
conn = JDBCUtil.getConnection();
// 3. 创建语句对象
ps = conn.prepareStatement(sql);
ps.setObject(1, id);
// 4. 执行SQL语句
rs = ps.executeQuery();
if (rs.next()) {
String name = rs.getString("name");
int age = rs.getInt("age");
Student stu = new Student(id, name, age);
return stu;
}
// 5. 释放资源
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCUtil.close(rs, ps, conn);
}
return null;
}
public List<Student> list() {
List<Student> list = new ArrayList<>();
String sql = "SELECT * FROM t_student ";
Connection conn = null;
Statement st = null;
ResultSet rs = null;
PreparedStatement ps=null;
try {
conn=JDBCUtil.getConnection();
// 3. 创建语句对象
ps = conn.prepareStatement(sql);
// 4. 执行SQL语句
rs = ps.executeQuery();
while (rs.next()) {
long id = rs.getLong("id");
String name = rs.getString("name");
int age = rs.getInt("age");
Student stu = new Student(id, name, age);
list.add(stu);
}
// 5. 释放资源
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCUtil.close(rs, ps, conn);
}
return list;
}
static {
// 1. 加载注册驱动
try {
ClassLoader loader = Thread.currentThread().getContextClassLoader();
InputStream inputStream = loader.getResourceAsStream("db.properties");
p = new Properties();
p.load(inputStream);
Class.forName(p.getProperty("driverClassName"));
} catch (Exception e) {
e.printStackTrace();
}
}
public static Connection getConnection() {
try {
// 2. 获取数据库连接
return DriverManager.getConnection(p.getProperty("url"), p.getProperty("username"),
p.getProperty("password"));
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
//查询统一模板
public static List<Student> query(String sql,Object...params){
List<Student> list=new ArrayList<>();
Connection conn = null;
PreparedStatement ps=null;
ResultSet rs = null;
try {
conn=JDBCUtil.getConnection();
ps=conn.prepareStatement(sql);
//设置值
for (int i = 0; i < params.length; i++) {
ps.setObject(i+1, params[i]);
}
rs = ps.executeQuery();
while (rs.next()) {
long id = rs.getLong("id");
String name = rs.getString("name");
int age = rs.getInt("age");
Student stu = new Student(id, name, age);
list.add(stu);
}
// 5. 释放资源
} catch (Exception e) {
e.printStackTrace();
} finally {
JDBCUtil.close(rs, ps, conn);
}
return list;
}
// 增加学生信息
public void save(Student stu) {
String sql = "INSERT INTO t_student(name,age) VALUES(?,?)";
Object[] params=new Object[]{stu.getName(),stu.getAge()};
JdbcTemplate.update(sql, params);
}
// 删除学生信息
public void delete(Long id) {
String sql = "DELETE FROM t_student WHERE id = ?";
JdbcTemplate.update(sql, id);
}
// 修改学生信息
public void update(Student stu) {
String sql = "UPDATE t_student SET name = ?,age = ? WHERE id = ?";
Object[] params=new Object[]{stu.getName(),stu.getAge(),stu.getId()};
JdbcTemplate.update(sql, params);
}
public Student get(Long id) {
String sql = "SELECT * FROM t_student WHERE id=?";
List<Student> list = JDBCTemplate.query(sql, id);
return list.size()>0? list.get(0):null;
}
public List<Student> list() {
String sql = "SELECT * FROM t_student ";
return JDBCTemplate.query(sql);
}
public interface IRowMapper {
//处理结果集
List rowMapper(ResultSet rs) throws Exception;
}
public static List<Student> query(String sql,IRowMapper rsh, Object...params){
List<Student> list = new ArrayList<>();
Connection conn = null;
PreparedStatement ps=null;
ResultSet rs = null;
try {
conn = JdbcUtil.getConnection();
ps = conn.prepareStatement(sql);
//设置值
for (int i = 0; i < params.length; i++) {
ps.setObject(i+1, params[i]);
}
rs = ps.executeQuery();
return rsh.mapping(rs);
// 5. 释放资源
} catch (Exception e) {
e.printStackTrace();
} finally {
JdbcUtil.close(rs, ps, conn);
}
return list ;
}
public Student get(Long id) {
String sql = "SELECT * FROM t_student WHERE id = ?";
List<Student> list = JdbcTemplate.query(sql,new StudentRowMapper(), id);
return list.size()>0? list.get(0):null;
}
public List<Student> list() {
String sql = "SELECT * FROM t_student ";
return JdbcTemplate.query(sql,new StudentRowMapper());
}
class StudentRowMapper implements IRowMapper{
public List mapping(ResultSet rs) throws Exception {
List<Student> list=new ArrayList<>();
while(rs.next()){
long id = rs.getLong("id");
String name = rs.getString("name");
int age = rs.getInt("age");
Student stu=new Student(id, name, age);
list.add(stu);
}
return list;
}
}
public static <T> T query(String sql,IRowMapper<T> rsh, Object...params){
Connection conn = null;
PreparedStatement ps=null;
ResultSet rs = null;
try {
conn = JdbcUtil.getConnection();
ps = conn.prepareStatement(sql);
//设置值
for (int i = 0; i < params.length; i++) {
ps.setObject(i+1, params[i]);
}
rs = ps.executeQuery();
return rsh.mapping(rs);
// 5. 释放资源
} catch (Exception e) {
e.printStackTrace();
} finally {
JdbcUtil.close(rs, ps, conn);
}
return null;
}
class StudentRowMapper implements IRowMapper<List<Student>>{
public List<Student> mapping(ResultSet rs) throws Exception {
List<Student> list=new ArrayList<>();
while(rs.next()){
long id = rs.getLong("id");
String name = rs.getString("name");
int age = rs.getInt("age");
Student stu=new Student(id, name, age);
list.add(stu);
}
return list;
}
}
public Long getCount(){
String sql = "SELECT COUNT(*) total FROM t_student";
Long totalCount = (Long) JdbcTemplate.query(sql,
new IRowMapper<Long>() {
public Long mapping(ResultSet rs) throws Exception {
Long totalCount = null;
if(rs.next()){
totalCount = rs.getLong("total");
}
return totalCount;
}
});
return totalCount;
}