一、原理:
1、做一个field注解,注解有两个参数:是否必填、toString之后的最大长度
2、对某个request类(或基类),使用注解标记某个字段的校验详情
3、通用的static方法,利用反射获取属性的值,并做校验。不通过则抛出特定的异常
二、上代码:
异常类:
package com.test;
/**
* 基础异常
* @author zyydd
* @date 2019/1/24 10:33
* @version 1.0.0
**/
public class BaseException extends RuntimeException {
/** 异常码 */
private String code;
/** 异常描述 */
private String desc;
public BaseException(){
}
public String getCode() {
return code;
}
private void setCode(String code) {
this.code = code;
}
public String getDesc() {
return desc;
}
private void setDesc(String desc) {
this.desc = desc;
}
public BaseException(String code, String desc) {
this(code, desc, new Throwable(desc));
}
public BaseException(String code, String desc, Throwable canse) {
super(new StringBuilder().append("code=").append(code).append(", desc=").append(desc).toString(), canse);
this.setCode(code);
this.setDesc(desc);
}
@Override
public String toString() {
return new StringBuilder().append(getClass().getName())
.append("{code=").append(this.getCode())
.append(", desc=").append(this.getDesc())
.append("}").toString();
}
}
测试的request类:
package com.test;
/**
* @author zyydd
* @date 2019/6/13 18:29
*/
public class TestChildRequest {
/**
* name
*/
@ParameterAttr(isNecessary = true, lengthLimit = 10)
private String name;
/**
* pin
*/
@ParameterAttr(lengthLimit = 15)
private String address;
@ParameterAttr(isNecessary = true)
private String school;
private String other;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getSchool() {
return school;
}
public void setSchool(String school) {
this.school = school;
}
public String getOther() {
return other;
}
public void setOther(String other) {
this.other = other;
}
}
field校验注解类:
package com.test;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* @author zyydd
* @date 2019/6/13 16:52
*/
@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ParameterAttr {
/**
* 是否必须,默认不必须
*
* @return
*/
boolean isNecessary() default false;
/**
* 属性toSring之后,最大长度
*
* @return
*/
int lengthLimit() default 0;
}
通用校验工具类及main测试方法:
package com.test;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
/**
* @author zyydd
* @date 2019/6/13 17:02
*/
public class ParameterCheckUtils {
private static Logger logger = LoggerFactory.getLogger(ParameterCheckUtils.class);
public static void commonCheck(Object obj) throws IllegalAccessException {
if (obj == null) {
logger.error("obj can not be null!");
throw new BaseException("9999", "obj can not be null!");
}
List<Field> fieldList = new ArrayList<Field>();
Class clazz = obj.getClass();
while (!Object.class.equals(clazz)) {
fieldList.addAll(Arrays.asList(clazz.getDeclaredFields()));
clazz = clazz.getSuperclass();
}
for (Field field : fieldList) {
field.setAccessible(true);
ParameterAttr attr = field.getAnnotation(ParameterAttr.class);
if (attr == null) {
continue;
}
Object paramObj = field.get(obj);
if (attr.isNecessary()) {
if (paramObj == null || StringUtils.isBlank(paramObj.toString())) {
logger.error("class={} field={} can not be null!", obj.getClass().getName(), field.getName());
throw new BaseException("9998", "field=" + field.getName() + " can not be null!");
}
}
if (attr.lengthLimit() > 0 && paramObj != null && StringUtils.isNotBlank(paramObj.toString())) {
if (paramObj.toString().length() > attr.lengthLimit()) {
logger.error("class={} field={} length is too long! limit={} but length={}", obj.getClass().getName(), field.getName(), attr.lengthLimit(), paramObj.toString().length());
throw new BaseException("9997", "field=" + field.getName() + " length is too long!");
}
}
}
logger.info("commonCheck success!");
}
public static void main(String[] args) throws IllegalAccessException {
//正常数据
TestChildRequest request1 = new TestChildRequest();
request1.setName("王钢蛋");
request1.setAddress("aabbccddeeaabbc");
request1.setSchool("北京市智障二中");
ParameterCheckUtils.commonCheck(request1);
//为空数据
try {
ParameterCheckUtils.commonCheck(null);
} catch (Exception e) {
logger.error("error1 ", e);
}
//必填没传的数据
try {
TestChildRequest request2 = new TestChildRequest();
request2.setName("王钢蛋");
request2.setAddress("aabbccddeeaabbc");
ParameterCheckUtils.commonCheck(request2);
} catch (Exception e) {
logger.error("error2 ", e);
}
//字段超长的数据
try {
TestChildRequest request3 = new TestChildRequest();
request3.setName("王钢蛋");
request3.setAddress("aabbccddeeaabbcc");
request3.setSchool("北京市智障二中");
ParameterCheckUtils.commonCheck(request3);
} catch (Exception e) {
logger.error("error3 ", e);
}
}
}
执行结果: