【SpringMVC】07 接受请求参数 & 域数据的选择

时间：2020-05-07 14:41:41 阅读：73 评论：0 收藏：0 [点我收藏+]

这是在没有RestFul方式获取的

我们的控制器处理方法，

只需要参数列表的参数标识跟请求的参数标识一致的即可

技术分享图片

如果不一致，我们可以对参数列表的参数注解上@RequestParam

写上和请求参数一样的标识即可

技术分享图片

如果要处理方法的参数以一个封装的实体类实例作为接受的容器，也是可以的

只要请求的参数标识符和，实体类的字段标识符是11对应的，就可以被接收到

例如我的这个POST表单，就像正常方式一样提交，也不会把参数暴露在URL中

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<form action="http://localhost:8080/SpringMVC02/getData" method="post">
    <p>用户 <input type="text" name="user_name"></p>
    <p>密码 <input type="password" name="user_password"></p>
    <p><input type="submit"></p>
</form>


</body>
</html>

然后这是我们的控制器方法

package cn.dai.controller;

import cn.dai.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PostMapping;

/**
 * @author ArkD42
 * @file SpringMVC
 * @create 2020 - 05 - 07 - 13:55
 */
@Controller
public class FormController {

    @PostMapping("/getData")
    public void getFormData(User user){
        System.out.println(user);
    }

}

访问测试之后，被模板引擎跳转拼接了

技术分享图片

这没有关系，我们的数据确实让处理的方法接收到了

技术分享图片

SpringMVC的三个域数据

-　Model

-　ModelMap

-　ModelAndView

Model类源码，功能不多，一看是一个接口

实际对象应该是好几个实现类来完成

主要是存储数据功能，和原先的Request差不多

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.ui;

import java.util.Collection;
import java.util.Map;
import org.springframework.lang.Nullable;

public interface Model {
    Model addAttribute(String var1, @Nullable Object var2);

    Model addAttribute(Object var1);

    Model addAllAttributes(Collection<?> var1);

    Model addAllAttributes(Map<String, ?> var1);

    Model mergeAttributes(Map<String, ?> var1);

    boolean containsAttribute(String var1);

    Map<String, Object> asMap();
}

ModelMap,继承LinkeHashMap

也就是具有该父类全部方法，功能很多

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.ui;

import java.util.Collection;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import org.springframework.core.Conventions;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

public class ModelMap extends LinkedHashMap<String, Object> {
    public ModelMap() {
    }

    public ModelMap(String attributeName, @Nullable Object attributeValue) {
        this.addAttribute(attributeName, attributeValue);
    }

    public ModelMap(Object attributeValue) {
        this.addAttribute(attributeValue);
    }

    public ModelMap addAttribute(String attributeName, @Nullable Object attributeValue) {
        Assert.notNull(attributeName, "Model attribute name must not be null");
        this.put(attributeName, attributeValue);
        return this;
    }

    public ModelMap addAttribute(Object attributeValue) {
        Assert.notNull(attributeValue, "Model object must not be null");
        return attributeValue instanceof Collection && ((Collection)attributeValue).isEmpty() ? this : this.addAttribute(Conventions.getVariableName(attributeValue), attributeValue);
    }

    public ModelMap addAllAttributes(@Nullable Collection<?> attributeValues) {
        if (attributeValues != null) {
            Iterator var2 = attributeValues.iterator();

            while(var2.hasNext()) {
                Object attributeValue = var2.next();
                this.addAttribute(attributeValue);
            }
        }

        return this;
    }

    public ModelMap addAllAttributes(@Nullable Map<String, ?> attributes) {
        if (attributes != null) {
            this.putAll(attributes);
        }

        return this;
    }

    public ModelMap mergeAttributes(@Nullable Map<String, ?> attributes) {
        if (attributes != null) {
            attributes.forEach((key, value) -> {
                if (!this.containsKey(key)) {
                    this.put(key, value);
                }

            });
        }

        return this;
    }

    public boolean containsAttribute(String attributeName) {
        return this.containsKey(attributeName);
    }
}

ModelAndView

携带和转发视图，附加了集合类的功能

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//

package org.springframework.web.servlet;

import java.util.Map;
import org.springframework.http.HttpStatus;
import org.springframework.lang.Nullable;
import org.springframework.ui.ModelMap;
import org.springframework.util.CollectionUtils;

public class ModelAndView {
    @Nullable
    private Object view;
    @Nullable
    private ModelMap model;
    @Nullable
    private HttpStatus status;
    private boolean cleared = false;

    public ModelAndView() {
    }

    public ModelAndView(String viewName) {
        this.view = viewName;
    }

    public ModelAndView(View view) {
        this.view = view;
    }

    public ModelAndView(String viewName, @Nullable Map<String, ?> model) {
        this.view = viewName;
        if (model != null) {
            this.getModelMap().addAllAttributes(model);
        }

    }

    public ModelAndView(View view, @Nullable Map<String, ?> model) {
        this.view = view;
        if (model != null) {
            this.getModelMap().addAllAttributes(model);
        }

    }

    public ModelAndView(String viewName, HttpStatus status) {
        this.view = viewName;
        this.status = status;
    }

    public ModelAndView(@Nullable String viewName, @Nullable Map<String, ?> model, @Nullable HttpStatus status) {
        this.view = viewName;
        if (model != null) {
            this.getModelMap().addAllAttributes(model);
        }

        this.status = status;
    }

    public ModelAndView(String viewName, String modelName, Object modelObject) {
        this.view = viewName;
        this.addObject(modelName, modelObject);
    }

    public ModelAndView(View view, String modelName, Object modelObject) {
        this.view = view;
        this.addObject(modelName, modelObject);
    }

    public void setViewName(@Nullable String viewName) {
        this.view = viewName;
    }

    @Nullable
    public String getViewName() {
        return this.view instanceof String ? (String)this.view : null;
    }

    public void setView(@Nullable View view) {
        this.view = view;
    }

    @Nullable
    public View getView() {
        return this.view instanceof View ? (View)this.view : null;
    }

    public boolean hasView() {
        return this.view != null;
    }

    public boolean isReference() {
        return this.view instanceof String;
    }

    @Nullable
    protected Map<String, Object> getModelInternal() {
        return this.model;
    }

    public ModelMap getModelMap() {
        if (this.model == null) {
            this.model = new ModelMap();
        }

        return this.model;
    }

    public Map<String, Object> getModel() {
        return this.getModelMap();
    }

    public void setStatus(@Nullable HttpStatus status) {
        this.status = status;
    }

    @Nullable
    public HttpStatus getStatus() {
        return this.status;
    }

    public ModelAndView addObject(String attributeName, @Nullable Object attributeValue) {
        this.getModelMap().addAttribute(attributeName, attributeValue);
        return this;
    }

    public ModelAndView addObject(Object attributeValue) {
        this.getModelMap().addAttribute(attributeValue);
        return this;
    }

    public ModelAndView addAllObjects(@Nullable Map<String, ?> modelMap) {
        this.getModelMap().addAllAttributes(modelMap);
        return this;
    }

    public void clear() {
        this.view = null;
        this.model = null;
        this.cleared = true;
    }

    public boolean isEmpty() {
        return this.view == null && CollectionUtils.isEmpty(this.model);
    }

    public boolean wasCleared() {
        return this.cleared && this.isEmpty();
    }

    public String toString() {
        return "ModelAndView [view=" + this.formatView() + "; model=" + this.model + "]";
    }

    private String formatView() {
        return this.isReference() ? "\"" + this.view + "\"" : "[" + this.view + "]";
    }
}

【SpringMVC】07 接受请求参数 & 域数据的选择

原文：https://www.cnblogs.com/mindzone/p/12842827.html

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