基於MyBatis註解擴充，實現無需配置即可使用__MyBatis

一、使用篇

      如果項目本身基於SpringMVC+Mybatis構建，不需添加任何配置Mapper類只需繼承BaseMapper，即擁有增刪改方法操作，無需任何設定檔

1.

package com.springmvc.mapper;import org.springframework.stereotype.Repository;import com.nmtx.mybatis.ext.mapper.BaseMapper;import com.springmvc.model.User;@Repositorypublic interface UserMapper extends BaseMapper<User>{}

2.

package com.springmvc.service.impl;import javax.annotation.Resource;import org.springframework.stereotype.Service;import com.springmvc.mapper.UserMapper;import com.springmvc.model.User;import com.springmvc.service.UserService;@Servicepublic class UserServiceImpl implements UserService{        @Resource    private UserMapper userMapper;        public int insertUser(User user) {        return userMapper.insert(user);    }    @Override    public int updateUser(User user) {        return userMapper.update(user);    }    @Override    public int deleteUser(User user) {        return userMapper.delete(user);    }    @Override    public User findUser(User user) {        return userMapper.findFirst(user);    }}

3.

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.springmvc.mapper.UserMapper">         </mapper>

擴充原理基於Mybatis中 @InsertProvider，@DeleteProvider，@UpdateProvider，@SelectProvider註解，具體實現代碼如下

1.

package com.nmtx.mybatis.ext.mapper;import org.apache.ibatis.annotations.DeleteProvider;import org.apache.ibatis.annotations.InsertProvider;import org.apache.ibatis.annotations.Options;import org.apache.ibatis.annotations.SelectProvider;import org.apache.ibatis.annotations.UpdateProvider;import com.nmtx.mybatis.ext.common.SqlProvider;public interface BaseMapper<T> {    @InsertProvider(type = SqlProvider.class, method = "insert")    @Options(useGeneratedKeys=true)    public int insert(T bean);    @DeleteProvider(type = SqlProvider.class, method = "delete")    public int delete(T bean);    @UpdateProvider(type = SqlProvider.class, method = "update")    public int update(T bean);    @SelectProvider(type = SqlProvider.class, method = "findFirst")    public T findFirst(T bean);

2.

package com.nmtx.mybatis.ext.common;import java.lang.reflect.Field;import java.util.ArrayList;import java.util.List;import org.apache.commons.lang3.ArrayUtils;import org.springframework.util.StringUtils;import com.nmtx.mybatis.ext.common.table.TableFormat;import com.nmtx.mybatis.ext.common.table.annotation.Column;import com.nmtx.mybatis.ext.common.table.annotation.Table;import com.nmtx.mybatis.ext.common.table.impl.HumpToUnderLineFormat;public class SqlProvider {            private TableFormat tableFormat = new HumpToUnderLineFormat();    public String insert(Object bean) {        Class<?> beanClass = bean.getClass();        String tableName = getTableName(beanClass);        Field[] fields = getFields(beanClass);        StringBuilder insertSql = new StringBuilder();        List<String> insertParas = new ArrayList<String>();        List<String> insertParaNames = new ArrayList<String>();        insertSql.append("INSERT INTO ").append(tableName).append("(");        try {            for (int i = 0; i < fields.length; i++) {                Field field = fields[i];                Column column = field.getAnnotation(Column.class);                String columnName = "";                if (column != null) {                    if (!column.required())                        continue;                    columnName = column.value();                }                if (StringUtils.isEmpty(columnName)) {                    columnName = tableFormat.getColumnName(field.getName());                }                field.setAccessible(true);                Object object = field.get(bean);                if (object != null) {                    insertParaNames.add(columnName);                    insertParas.add("#{" + field.getName() + "}");                }            }        } catch (Exception e) {            new RuntimeException("get insert sql is exceptoin:" + e);        }        for (int i = 0; i < insertParaNames.size(); i++) {            insertSql.append(insertParaNames.get(i));            if (i != insertParaNames.size() - 1)                insertSql.append(",");        }        insertSql.append(")").append(" VALUES(");        for (int i = 0; i < insertParas.size(); i++) {            insertSql.append(insertParas.get(i));            if (i != insertParas.size() - 1)                insertSql.append(",");        }        insertSql.append(")");        return insertSql.toString();    }    public String update(Object bean) {        Class<?> beanClass = bean.getClass();        String tableName = getTableName(beanClass);        Field[] fields = getFields(beanClass);        StringBuilder updateSql = new StringBuilder();        updateSql.append(" update ").append(tableName).append(" set ");        try {            for (int i = 0; i < fields.length; i++) {                Field field = fields[i];                Column column = field.getAnnotation(Column.class);                String columnName = "";                if (column != null) {                    if (!column.required())                        continue;                    columnName = column.value();                }                if (StringUtils.isEmpty(columnName)) {                    columnName = tableFormat.getColumnName(field.getName());                }                field.setAccessible(true);                Object beanValue = field.get(bean);                if (beanValue != null) {                    updateSql.append(columnName).append("=#{").append(field.getName()).append("}");                    if (i != fields.length - 1) {                        updateSql.append(",");                    }                }            }        } catch (Exception e) {            new RuntimeException("get update sql is exceptoin:" + e);        }        updateSql.append(" where ").append(tableFormat.getId()+" =#{id}");        return updateSql.toString();    }    public String delete(Object bean) {        Class<?> beanClass = bean.getClass();        String tableName = getTableName(beanClass);        Field[] fields = getFields(beanClass);        StringBuilder deleteSql = new StringBuilder();        deleteSql.append(" delete from ").append(tableName).append(" where  ");        try {            for (int i = 0; i < fields.length; i++) {                Field field = fields[i];                Column column = field.getAnnotation(Column.class);                String columnName = "";                if (column != null) {                    if (!column.required())                        continue;                    columnName = column.value();                }                if (StringUtils.isEmpty(columnName)) {                    columnName = tableFormat.getColumnName(field.getName());                }                field.setAccessible(true);                Object beanValue = field.get(bean);                if (beanValue != null) {                    deleteSql.append(columnName).append("=#{").append(field.getName()).append("}");                    if (i != fields.length - 1) {                        deleteSql.append(" and ");                    }                }            }        } catch (Exception e) {            new RuntimeException("get delete sql is exceptoin:" + e);        }        return deleteSql.toString();    }    public String findFirst(Object bean) {        Class<?> beanClass = bean.getClass();        String tableName = getTableName(beanClass);        Field[] fields = getFields(beanClass);        StringBuilder selectSql = new StringBuilder();        List<String> selectParaNames = new ArrayList<String>();        List<String> selectParas = new ArrayList<String>();        selectSql.append("select ");        try {            for (int i = 0; i < fields.length; i++) {                Field field = fields[i];                Column column = field.getAnnotation(Column.class);                String columnName = "";                if (column != null) {                    if (!column.required())                        continue;                    columnName = column.value();                }                if (StringUtils.isEmpty(columnName)) {                    columnName = tableFormat.getColumnName(field.getName());                }                field.setAccessible(true);                Object object = field.get(bean);                selectSql.append(field.getName());                if (object != null) {                    selectParaNames.add(columnName);                    selectParas.add("#{" + field.getName() + "}");                }                if (i != fields.length - 1)                    selectSql.append(",");            }        } catch (Exception e) {            new RuntimeException("get select sql is exceptoin:" + e);        }        selectSql.append(" from ").append(tableName).append(" where ");        for (int i = 0; i < selectParaNames.size(); i++) {            selectSql.append(selectParaNames.get(i)).append("=").append(selectParas.get(i));            if (i != selectParaNames.size() - 1)                selectSql.append(" and ");        }        return selectSql.toString();    }    private String getTableName(Class<?> beanClass) {        String tableName = "";        Table table = beanClass.getAnnotation(Table.class);        if (table != null) {            tableName = table.value();        } else {            tableName = tableFormat.getTableName(beanClass.getSimpleName());        }        return tableName;    }    private Field[] getFields(Class<?> beanClass) {        Field[] beanFields = beanClass.getDeclaredFields();        Class<?> beanSuperClass = beanClass.getSuperclass();        Field[] beanSuperFields = beanSuperClass.getDeclaredFields();        return ArrayUtils.addAll(beanFields, beanSuperFields);    }}