准备工作:
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1:数据库表
CREATE TABLE `t_permission` (
`id` int(11) NOT NULL AUTO_INCREMENT COMMENT '权限ID',
`type` int(11) NOT NULL COMMENT '权限类型',
`name` varchar(255) NOT NULL COMMENT '权限名称',
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=24 DEFAULT CHARSET=utf8 COMMENT='权限表';
2:准备实体类
public class TPermissionEntity {
@PrimaryKey //下面步骤2中自定义注解
private Integer id;//权限ID
private Integer type;//权限类型
private String name;//权限名称
//省略了get,set方法....
}
步骤1:编写工具类Tools:作用:用于驼峰和数据库字段的转换
因为类的名称用的是驼峰命名,所以这里需要转换一下
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/*
* 驼峰名称和下划线名称的相互转换
*/
public class Tool {
private static Pattern linePattern = Pattern.compile("_(\\w)");
/** 下划线转驼峰 */
public static String lineToHump(String str) {
str = str.toLowerCase();
Matcher matcher = linePattern.matcher(str);
StringBuffer sb = new StringBuffer();
while (matcher.find()) {
matcher.appendReplacement(sb, matcher.group(1).toUpperCase());
}
matcher.appendTail(sb);
return sb.toString();
}
private static Pattern humpPattern = Pattern.compile("[A-Z]");
/** 驼峰转下划线,效率比上面高 */
public static String humpToLine(String str) {
Matcher matcher = humpPattern.matcher(str);
StringBuffer sb = new StringBuffer();
while (matcher.find()) {
matcher.appendReplacement(sb, "_" + matcher.group(0).toLowerCase());
}
matcher.appendTail(sb);
return sb.toString();
}
}
步骤2:自定义两个注解,分别用于类字段的排除和字义主键
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface Exclude {
}
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
public @interface PrimaryKey {
String value() default "";
}
步骤3:自定义动态sql生成类BaseSqlProvider
作用:根据传入的对象动态获取表名和字段名生成动态的sql语句,再执行
@Insert,@Select,@update,@Delete是直接配置SQL语句，而@InsertProvider,@UpdateProvider,@SelectProvider,@DeleteProvider则是通过SQL工厂类及对应的方法生产SQL语句
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
import org.apache.ibatis.annotations.Options;
import org.apache.ibatis.jdbc.SQL;
import com.example.demo.common.utils.Tool;
public class BaseSqlProvider {
@Options
public String add(T bean) {
SQL sql = new SQL();
Class clazz = bean.getClass();
String tableName = clazz.getSimpleName();
String realTableName = Tool.humpToLine(tableName).replaceAll("_entity", "").substring(1);
sql.INSERT_INTO(realTableName);
List fields = getFields(clazz);
for (Field field : fields) {
field.setAccessible(true);
String column = field.getName();
System.out.println("column:" + Tool.humpToLine(column));
sql.VALUES(Tool.humpToLine(column), String.format("#{" + column + ",jdbcType=VARCHAR}"));
}
return sql.toString();
}
public String delete(T bean) {
SQL sql = new SQL();
Class clazz = bean.getClass();
String tableName = clazz.getSimpleName();
String realTableName = Tool.humpToLine(tableName).replaceAll("_entity", "").substring(1);
sql.DELETE_FROM(realTableName);
List primaryKeyField = getPrimarkKeyFields(clazz);
if (!primaryKeyField.isEmpty()) {
for (Field pkField : primaryKeyField) {
pkField.setAccessible(true);
sql.WHERE(pkField.getName() + "=" + String.format("#{" + pkField.getName() + "}"));
}
} else {
sql.WHERE(" 1= 2");
throw new RuntimeException("对象中未包含PrimaryKey属性");
}
return sql.toString();
}
private List getPrimarkKeyFields(Class clazz) {
List primaryKeyField = new ArrayList<>();
List fields = getFields(clazz);
for (Field field : fields) {
field.setAccessible(true);
PrimaryKey key = field.getAnnotation(PrimaryKey.class);
if (key != null) {
primaryKeyField.add(field);
}
}
return primaryKeyField;
}
private List getFields(Class clazz) {
List fieldList = new ArrayList<>();
Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
field.setAccessible(true);
Exclude key = field.getAnnotation(Exclude.class);
if (key == null) {
fieldList.add(field);
}
}
return fieldList;
}
public String get(T bean) {
SQL sql = new SQL();
Class clazz = bean.getClass();
String tableName = clazz.getSimpleName();
String realTableName = Tool.humpToLine(tableName).replaceAll("_entity", "").substring(1);
sql.SELECT("*").FROM(realTableName);
List primaryKeyField = getPrimarkKeyFields(clazz);
if (!primaryKeyField.isEmpty()) {
for (Field pkField : primaryKeyField) {
pkField.setAccessible(true);
sql.WHERE(pkField.getName() + "=" + String.format("#{" + pkField.getName() + "}"));
}
} else {
sql.WHERE(" 1= 2");
throw new RuntimeException("对象中未包含PrimaryKey属性");
}
System.out.println("getSql:"+sql.toString());
return sql.toString();
}
public String update(T bean) {
SQL sql = new SQL();
Class clazz = bean.getClass();
String tableName = clazz.getSimpleName();
String realTableName = Tool.humpToLine(tableName).replaceAll("_entity", "").substring(1);
sql.UPDATE(realTableName);
List fields = getFields(clazz);
for (Field field : fields) {
field.setAccessible(true);
String column = field.getName();
if (column.equals("id")) {
continue;
}
System.out.println(Tool.humpToLine(column));
sql.SET(Tool.humpToLine(column) + "=" + String.format("#{" + column + ",jdbcType=VARCHAR}"));
}
List primaryKeyField = getPrimarkKeyFields(clazz);
if (!primaryKeyField.isEmpty()) {
for (Field pkField : primaryKeyField) {
pkField.setAccessible(true);
sql.WHERE(pkField.getName() + "=" + String.format("#{" + pkField.getName() + "}"));
}
} else {
sql.WHERE(" 1= 2");
throw new RuntimeException("对象中未包含PrimaryKey属性");
}
System.out.println("updateSql:"+sql.toString());
return sql.toString();
}
}
步骤4:编写BaseMapper基类接口
public interface BaseMapper {
//新增一条数据
@InsertProvider(method = "add",type=BaseSqlProvider.class)
@Options(useGeneratedKeys=true)
public int add(T bean);
//根据主键删除一条数据
@DeleteProvider(method = "delete",type=BaseSqlProvider.class)
public int delete(T bean);
//根据主键获取一条数据
@SelectProvider(method = "get",type=BaseSqlProvider.class)
public T get(T bean);
//修改一条数据
@UpdateProvider(method = "update",type=BaseSqlProvider.class)
public int update(T bean);
}
说明：@InsertProvider注解中的type指明自定义的SQL工厂类，method是工厂类里对应的方法,方法返回的是对方的sql语句
到这里基类以及它的配置就完成了,接下来,可以使用了
举例:无锡看妇科的医院 http://www.ytsg120.cn/
编写一个TPermissionMapper接口,实现BaseMapper类,并传入一个泛型参数,此时这个TPermissionMapper接口已经具备了,BaseMapper中基本的增/删/改/查功能.同时TPermissionMapper还可以再写自己独有的方法和mapper.xml文件对功能进行扩展
public interface TPermissionMapper extends BaseMapper{
//List queryByPage();
}
在controller当中的应用:
@Controller
public class LoginController {
@Autowired
private TPermissionMapper tPermissionMapper;
//新增
@ResponseBody
@RequestMapping(value = "/add")
public Integer add() {
TPermissionEntity permissionEntiry = new TPermissionEntity();
permissionEntiry.setName("test");
permissionEntiry.setType(3);
Integer num = tPermissionMapper.add(permissionEntiry);
return num;
}
//修改
@ResponseBody
@RequestMapping(value = "/update")
public Integer update() {
TPermissionEntity permissionEntiry = new TPermissionEntity();
permissionEntiry.setId(23);
permissionEntiry.setName("test");
permissionEntiry.setType(3);
Integer num = tPermissionMapper.update(permissionEntiry);
return num;
}
//查询
@ResponseBody
@RequestMapping(value = "/query")
public TPermissionEntity query() {
TPermissionEntity tPermissionEntity = new TPermissionEntity();
tPermissionEntity.setId(23);
tPermissionEntity= (TPermissionEntity) tPermissionMapper.get(tPermissionEntity);
return tPermissionEntity;
}
//删除
@ResponseBody
@RequestMapping(value = "/delete")
public Integer delete() {
TPermissionEntity permissionEntiry = new TPermissionEntity();
permissionEntiry.setId(22);
Integer num = tPermissionMapper.delete(permissionEntiry);
return num;
}